Natural Rubber Conversion To Limonene by Vacuum Pyrolysis in Presence of Solid Catalyst [PDF]

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NATURAL RUBBER CONVERSION TO LIMONENE BY VACUUM PYROLYSIS IN PRESENCE OF SOLID CaO/SiO2 CATALYST



A THESIS Submitted in Fulfillment of the Requirements for the Degree of Magister Teknik (M.T.) in Chemical Engineering Program Faculty of Engineering University of Sriwijaya



By: HAERANI YULIYATI ID. 03122803002



ENGINEERING FACULTY SRIWIJAYA UNIVERSITY AUGUST 2014 APPROVAL PAGE



2



Title of Thesis



: Natural Rubber Conversion to Limonene by Vacuum Pyrolysis in Presence of Solid CaO/SiO2 Catalyst



Name



: Haerani Yuliyati



Student ID. No.



: 03122803002



Program



: Master of Chemical Engineering



Academic Major



: Energy/Environmental Technology and Management



Approved by:



Advisor I



Advisor II



Dr. Ir. Hj. Sri Haryati, DEA NIP. 195610241981032001



Prof. Dr. Ir. H. M. Djoni Bustan, M.Eng NIP. 195603071981031010



Head of Chemical Engineering Master Program



Dr. Ir. Hj. Sri Haryati, DEA NIP. 195610241981032001



Dean of Engineering Faculty



Prof. Dr. Ir. H. M. Taufik Toha, DEA NIP. 195308141985031002



DATE OF GRADUATION:



JULY 25th, 2014



STATEMENT PAGE



3



Name



: Haerani Yuliyati



Date of Birth



: July 27th, 1987



Program



: Master of Chemical Engineering



Academic Major



: Energy/Environmental Technology and Management



Student ID. No.



: 03122803002



Tittle of Thesis



: Natural Rubber Conversion to Limonene by Vacuum Pyrolysis in Presence of Solid CaO/SiO2 Catalyst



Hereby states that: 1. All data, information, interpretation and declaration in the discussion and conclusion presented herein, except for the ones mentioned by the source are the result of my observation and thought with guidance of my advisors. 2. The thesis that I wrote is original and has never been handed in for any academic degree, neither at Sriwijaya University nor other universities. I certify that these statements are true, and if one day an evidence of violation for these statements is found within this work, I am willing to accept the sanction of academic degree cancellation that I received by this thesis.



Palembang,



August 2014



Haerani Yuliyati ID. 03122803002



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ACKNOWLEDGEMENTS



In the name of Allah, the Most Beneficent and the Most Merciful, writer would like to hail all praise to Allah SWT for His blessing throughout the whole compiling process of NATURAL RUBBER CONVERSION TO LIMONENE BY VACUUM PYROLYSIS IN PRESENCE OF SOLID CaO/SiO2 CATALYST thesis report. Writer would also like to utter sholawat and salaam for her beloved prophet Muhammad SAW. This page is opened with a sincere and deep gratitude from writer, expressed for Dr. Ir. Hj. Sri Haryati, DEA and Prof. Dr. Ir. H.M. Djoni Bustan M.Eng as her advisors for their superb supports, encouragements and guidance during the research and writing process. A tender love and respect to writer’s dearest parents and siblings for their outstanding and irreplaceable roles. Last but not least, appreciations toward other parties involved in the nearly two years of the writer’s study as follows: 1. National Education Ministry which has provided the scholarship for Master program. 2. The Head of Chemical Engineering Master Program, Dr. Ir. Hj. Sri Haryati, DEA. 3. Lecturers of Energy/Environment program and academic staff in Chemical Engineering Graduate Program. 4. Mr. I Made Swetra at Palembang Police Forensic Laboratory who has been extremely helpful. 5. Fellow colleagues of Double Degree Program and other individuals that contribute ingenuously in the working process that may not be written one by one. Final words to round off are that the writer personally wishes that this work may be helpful for future study of the same research theme. Nevertheless, critics and suggestions for further improvement are also very welcomed and fully considered by the writer. Palembang,



August 2014



Writer



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ABSTRACT Natural rubber latex transforms to a very valuable asset when technology is able to change it into varied industry goods. Moreover, natural rubber is known as the potential source of many valuable compounds. Limonene in particular, is a very valuable chemical compound that may be used in the formulation of industrial solvents, resins, adhesives, a dispersing agent for pigments and a feedstock for the production of fragrances and flavorings. Therefore, it is necessary to design optimum conditions to selectively produce a narrow range of hydrocarbons by studying the effect of catalyst activity and temperature. Using 80 grams of natural rubber as fixed variable, catalytic vacuum pyrolysis experiment was conducted. The experiment varied natural rubber to CaO/SiO 2 catalyst weight ratio and reaction temperature. 80, 100 and 120 grams of catalyst were used in pyrolysis with varying temperature from 325, 350, 375 and 400oC. Pyrolytic oils produced were analyzed qualitatively using GC/MS. The highest limonene content was found in pyrolytic oil that used 120 grams of CaO/SiO 2 catalyst with pyrolysis temperature at 400oC, as much as 14.89% area.



Keywords: natural rubber, CaO catalyst, pyrolysis, limonene



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TABLE OF CONTENTS ACKNOWLEDGEMENTS..................................................................................................... ii TABLE OF CONTENTS......................................................................................................... iii LIST OF FIGURES.................................................................................................................. iv LIST OF TABLES ................................................................................................................... v LIST OF APPENDIX............................................................................................................... vi CHAPTER I



INTRODUCTION....................................................................................... 1.1. Background........................................................................................... 1.2. Problem Statement................................................................................ 1.3. Objectives............................................................................................. 1.4. Benefits.................................................................................................



CHAPTER II



LITERATURE REVIEW............................................................................. 5 2.1. Development on Natural Rubber Conversion to Limonene-Containing Pyrolytic Oil Technologies.................................................................... 5 2.2. Basic Theory......................................................................................... 8 2.3. Description Process of Previous Researches........................................ 47 2.4. Reaction Mechanism............................................................................. 51



CHAPTER III



RESEARCH CONCEPT DESIGN.............................................................. 53 3.1. Materials............................................................................................... 53 3.2. Catalyst Preparation.............................................................................. 54 3.3. Experimental Process Description........................................................ 56



CHAPTER IV



RESULTS AND DISCUSSION................................................................... 59 4.1. Catalyst Characterization...................................................................... 59 4.2. Pyrolytic Oil Characterization.............................................................. 60



CHAPTER V



CONCLUSION............................................................................................ 68



REFERENCES APPENDIX



1 1 3 4 4



................................................................................................................... 69 ...................................................................................................................... 73



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LIST OF FIGURES Figure 2.1. cis-1,4-polyisoprene Chemical Structure................................................................8 Figure 2.2. Isoprene Chemical Structural................................................................................16 Figure 2.3. Limonene Chemical Structure...............................................................................20 Figure 2.4. Limonene Derivation.............................................................................................22 Figure 2.5. Structure of faujasite..............................................................................................26 Figure 2.6. T:O and T:O:T arrangements in clays....................................................................29 Figure 2.7. Simplified Diagrams Summarizing Methods of Blending, Transforming and Mounting Catalytic Components...........................................................................33 Figure 2. 8. Schematic Diagram of Experimental Apparatus..................................................47 Figure 2. 9. Fixed Bed Reactor Schematic...............................................................................48 Figure 2.10. Schematic Diagram of the Pyrolysis Installation................................................50 Figure 3.1. Catalyst Preparation Steps.....................................................................................54 Figure 3.2. Catalytic Vacuum Pyrolysis Reaction of Natural Rubber Conversion Apparatus. 56 Figure 3.3. Catalytic Pyrolysis Reaction of Natural Rubber Conversion Apparatus...............57 Figure 4.1. SEM analysis of CaO/SiO2 catalyst.......................................................................59 Figure 4.2. Effect of Temperature on Pyrolytic Oil Percent Area for Catalytic Pyrolysis Reaction with 80 gram Catalyst and 80 gram Natural Rubber..............................61 Figure 4.3. Effect of Temperature on Pyrolytic Oil Percent Area for Catalytic Pyrolysis Reaction with 100 gram Catalyst and 80 gram Natural Rubber............................62 Figure 4.4. Effect of Temperature on Pyrolytic Oil Percent Area for Catalytic Pyrolysis Reaction with 120 gram Catalyst and 80 gram Natural Rubber............................63 Figure 4.5. Effect of Natural Rubber to Catalyst Ratio and Temperature on Limonene Peak Area in Pyrolytic Oil..............................................................................................64 Figure 4.6. Effect of Natural Rubber to Catalyst Ratio and Temperature on Naphthalene Peak Area in Pyrolytic Oil..............................................................................................65 Figure 4.7. Effect of Natural Rubber to Catalyst Ratio and Temperature on Aromatic Compounds Peak Area in Pyrolytic Oil.................................................................66



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LIST OF TABLES Table 1.1. Rank of Countries in the World with Higher Rubber Plantation Production............2 Table 2.1. Natural Rubber Characteristic.................................................................................10 Table 2.2. Degradation and Solubility Temperature of Some Rubber Type.............................13 Table 2.3. Isoprene Chemical Properties..................................................................................17 Table 2.4. Limonene Chemical Properties...............................................................................21 Table 2.5. Si/Al ratios for four types of zeolite (Source : E. B. M. Daesburg, 1993)..............27 Table 3.1. Natural Rubber Composition...................................................................................53 Table 4.1. Product Distribution of Natural Rubber from Varied Pyrolysis Condition.............60



LIST OF APPENDIX GCMS ANALYSIS OF PYROLITIC RESULTS..................................................................... 73 ANALYSIS SAMPLE COMPOSITION................................................................................. 79 EXPERIMENTAL APPARATUS............................................................................................ .....................................................................................................................................104



CHAPTER I INTRODUCTION



1.1. Background Natural rubber latex transforms to a very valuable asset when technology is able to change it into varied industry goods. Unfortunately, the price of natural rubber is dependent to buyer countries instead of the natural rubber producer countries. Several countries then start to develop rubber plant as their plantation commodity. Indonesia for



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instance, whose rubber plantation area reaches over 3 million acre, is also supposedly sees this issue as an opportunity. Unfortunately, this large plantation area hasn’t received optimum production; in the other words it doesn’t give major effect to world’s natural rubber marketing. As it can be seen from the fact that Malaysia and Thailand whose rubber plantation area are smaller than that of Indonesia’s are able to compete with Indonesia’s natural rubber production. It’s not only production number, but also the low quality and quantity of Indonesia natural rubber production in world market. Indonesia has been widely known as one of the largest producers of natural rubber plant in the world. Other than acts as Indonesia’s income source and society welfare or economy growth booster of new rural area around natural rubber plantation, this commodity gives significant contribution as the country’s income, natural rubber plantation does not achieve decent attention, considering 84% of Indonesia’s natural rubber production is exported in the form of raw rubber while domestic rubber consumption only reach 16%. Natural rubber is one of Indonesia’s plantation commodities that hold a very important role in Indonesia economy. Along with palm tree, rubber plants are the biggest income source from plantation sector. In the last five years, rubber plant contributes 25% to 40% of total plantation product export. Indonesia is the largest natural rubber producer country after Thailand, where in 2012 Indonesia natural rubber production reached 3.27 million ton and, together with Thailand, takes over ± 27% and ± 30% world’s need of natural rubber. World’s natural rubber consumption has reached 10.94 milliom ton. As revealed by Rubber Research Center representative, Sinung Hendratno, there are five natural rubber major producer countries in the world. Table 1.1. Rank of Countries in the World with Higher Rubber Plantation Production Country



Rubber Production



10



Thailand



3.393.800



Indonesia



2.982.000



Malaysia



996.200



India



892.700



Vietnam



811.600



1. Thailand. Thailand’s natural rubber production is the largest in the world. In 2011, it has managed to fulfil 30.80% of world’s natural rubber need. 2. Indonesia. Indonesia is the second largest producer of natural rubber, where it contributes 27.06% to world’s natural rubber production. Yet, Indonesia productivity is still very weak, that is only 986 kg per acre a year. 3. Malaysia. Malaysia contributes 9.04% to world’s natural rubber production. Total plantation area in Malaysia is 1.020.000 acre with 93.7% is public owned. This plantation area produce 1.450 kilogram per acre per year. 4. India In 2011, the natural rubber production of India contribute as much as 8.10% to the world’s natural rubber production.



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5. Vietnam Based on 2011 production data, Vietnam’s natural rubber production reaches 811.600 ton. Therefore, it contributes as many as 7.37% to world’s natural rubber production. Expert’s studies showed the tendencies that world’s natural rubber consumption gives a good prospect. Thus, Indonesia is supposed to take this opportunity to maximize natural rubber production. Moreover, natural rubber is known as the potential source of many valuable compounds, such as benzene, toluene, xylene, naphthalene, limonene, other aromatic compounds and their derivatives. These chemical products have high value and wide industrial applications. Limonene in particular, is a very valuable chemical compound that may be used in the formulation of industrial solvents, resins, adhesives, a dispersing agent for pigments and a feedstock for the production of fragrances and flavorings (Hanson, et al. 1999), not to mention its expensive market price. Besides, limonene is biodegradable, environmentally safe with excellent solvency, rinsability and high wetting penetration (Hanson, et al. 1999). Therefore, it is necessary to design optimal conditions to selectively produce a narrow range of hydrocarbons, such as dl-limonene (Zhang, et al. 2008). 1.2. Problem Statement Natural rubber abundant production from Indonesia rubber plantation is a very great opportunity that it is very unfortunate to be missed. Moreover, when technologies are able to transforms natural rubber from lower value compound to higher value compounds.



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There have been many researches conducted to put an added value to natural rubber, such as natural rubber pyrolysis to limonene. Unfortunately, the result yield of limonene from those researches can not be satisfactory for industry scale. Some researchers used additives or catalyst to improve limonene yield and found out that catalytic activity was limited on producing limonene. It is the obvious reason why most researchers use high temperature reaction. Therefore, it is not preferable regarding the cost production 1.3. Objectives 1. To study the effect of catalyst activity by varying CaO/SiO 2 to natural rubber weight ratio on limonene content in pyrolitic oil. 2. To investigate temperature role on the formation of limonene from the catalytic reaction of natural rubber conversion. 1.4. Benefits This research is expected to conveniently contribute: 1. As a reference for the development of other researches in natural rubber conversion to more valuable compounds. 2. As the base for pilot plant scale research which is to be upgraded from laboratory scale research.



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CHAPTER II LITERATURE REVIEW



2.1. Development on Natural Rubber Conversion to Limonene-Containing Pyrolytic Oil Technologies There have been some experiments conducted regarding valuable hydrocarbon compounds production from natural rubber based materials over the years by many scientists all over the world. In majority, they utilized waste or scrap tires that have been designated as a priority waste stream by the European Commission and as such are subject to recycling target and recommendations regarding environmentally acceptable treatment and disposal methods. An alternative technology to dispose waste tires is pyrolysis that is the thermal degradation of the tire in an inert atmosphere (Bajus and Olahova 2011). Pyrolysis is an environmentally friendly process that converts waste tires to flammable gas, pyrolytic oil, and carbon black, all of which are potentially recyclable. The flammable gas can provide energy for the pyrolysis process, while carbon black can be used as a low-grade carbon black and pyrolytic oil can be used as liquid fuel after extracting chemical materials, such as benzene, toluene, xylene, and dl-limonene. These chemical products have high value and wide industrial applications. To enhance the value of waste tire pyrolysis process, optimal conditions should be designated to selectively produce a narrow range of hydrocarbons, such as dl-limonene, benzene and derivatives (Zhang, et al. 2008). A number of different natural and synthetic rubbers and rubber formulation are used to produce tires (Bajus and Olahova 2011). It is well known that natural rubber decomposes to form oligomers of isoprene, ranging from the monomer unit up to



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hexamers. The major compound is usually dipentene, also known as limonene, which represents the dimmer (Hall, Zakaria and Williams 2009). Polyisoprene or natural rubber composes approximately 50-60% of tire formulation; both represent the ideal source of limonene. Tire elastomers other than polyisoprene are not the main source of dl-limonene (Pakdel, Pantea and Roy 2001). Processing of waste rubber by pyrolysis has been intensively investigated in recent years, particularly with regard to scrap tires. The pyrolysis of natural rubber has also been investigated, as has the pyrolysis of natural rubber’s main constituent, polyisoprene (Hall, Zakaria and Williams 2009). Significant research has been performed in the field of chemical recycling of rubbers by pyrolysis in 2009 by Zhang et. al. who studied the influence of temperature and two additives, i.e. natrium hydroxide (NaOH) and natrium carbonate (Na2CO3) on the yields of the pyrolysis products, as well as the formation mechanism and variation of dl-limonene content in the pyrolysis oil. The experiment results indicated that NaOH additive use in vacuum pyrolysis of waste tire could lower pyrolysis temperature and slightly increase dl-limonene content in pyrolytic oil in experiment run at the same temperature. However, though the addition of Na 2CO3 additive gave the same trend to increase dl-limonene content, it did not promote the pyrolysis reaction. Zhang et. al. experiment also showed that limonene content as the main component in pyrolytic naphtha under vacuum pyrolysis conditions was greater than that in other atmospheric pyrolyis process. Another investigation of catalytically upgrading pyrolysis process of natural rubber was conducted by Hall et. al. in 2009. They passed rubber gloves that were manufactured from natural rubber over Y-zeolite catalyst before they exited reactor. The samples were pyrolized in a fixed bed reactor at either 380 oC or 480oC. Even though the introduction of catalyst increased the concentration of aromatics in pyrolytic oil, it caused



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a large decrease in the yield of limonene. It fell from 108.8 mg/g sample to 0.9 mg/gsample when the reaction temperature is 380oC and from 120.5 mg/gsample to 2.2 mg/gsample for pyrolysis at 480oC. Pyrolysis is limited by heat and mass transfer between the particle and, consequently, as particle size is decreased the apparent kinetic constant increases. According to Bajus and Olahova, pyrolysis oil characteristics strongly depend on pyrolysis process characteristics, process temperature and nature of the raw material used. In 2011, they converted scrap tires with the aim to study the experimental conditions that maximized liquid yields. Maximum liquid component obtained as much as 9.0%wt is d, l-limonene, produced at reaction temperature of 450 oC. Yet, with the increasing temperature to 570oC it dropped to 4.6%wt along with other aromates C 7-C10. This behaviour of aromatic fraction is due to Diels-Alder reactions that promote the formation of aromatic compounds from Olefins (Bajus and Olahova 2011). In addition to pyrolysis conversion technology, there is another approach to utilize carbonaceous waste, called co-pyrolysis. Onenc et. al. for instance, who co-pyrolized scrap tires and oily waste from ships to liquid fuels or chemical feedstock in the presence and absence of catalysts. Their work was aimed to see the influence of catalyst use and reaction temperature. It is reported that there was no influence of temperature on the product distribution over 500oC in scrap tires pyrolysis. The catalyst showed similar activity but Red Mud catalyst left fewer residues than that compared to ReUS-Y faujisite catalyst. Nevertheless, both catalysts had great effect on the distribution of compounds in the pyrolysis oils of scrap tires-oily waste mixture, particularly in D-limonene amount. In accordance to review of some researches conducted over the last three decades, oil yields fluctuated with both temperatures and heating rates with no discernible trend (Quek and Balasubramanian 2013). It is also stated that low pyrolysis temperature and



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pressure as well as short vapour residence time increased the limonene yield (Pakdel, Pantea and Roy 2001). As when catalysts, such as HZSM-5, HY and HBeta zeolites were occupied in reaction, gas yield and light aromatic hydrocarbon increase at the expense of the decreasing limonene yield (Quek and Balasubramanian 2013). The production of limonene from natural rubber has always been done in high operating conditions affecting the operational cost. This phenomenon obviously is not favourable for industrial scale application of limonene production. Therefore, it is necessary to investigate the required operating conditions in the method to obtain high yield of limonene with proportional operating cost. The role of catalyst may also take part in the process, so that either limonene decomposition into lighter hydrocarbon compounds or the formation of higher hydrocarbon compounds than limonene can be prohibited. This ability can be determined by catalyst activity provided by the ratio of natural rubber as feedstock and catalyst weight ratio used in the fixed bed reactor. 2.2. Basic Theory 2.2.1.



Natural Rubber Natural rubber, as initially produced, consists of polymers of the organic



compound isoprene, with minor impurities of other organic compounds plus water. Forms of polyisoprene that are useful as natural rubbers are classified as elastomers. The major compound that composed natural rubber is cis-1,4-polyisoprene, polymer of isoprene with high molecular weight (Heinz-Hermann 2000).



Figure 2.1. cis-1,4-polyisoprene Chemical Structure



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Currently, rubber is harvested mainly in the form of the latex from certain trees. The latex is a sticky, milky colloid drawn off by making incisions into the bark and collecting the fluid in vessels in a process called “tapping”. The latex then is refined into rubber ready for commercial processing. Natural rubber is used extensively in many applications and products, either alone or in combination with other materials. In most of its useful forms, it has large stretch ratio, high resilience, and is extremely waterproof (Heinz-Hermann 2000). The major commercial source of natural rubber latex is the Para rubber tree (Hevea brasiliensis), a member of the spurge family, Euphorbiaceae. This species is widely used because it grows well under cultivation and a properly managed tree responds to wounding by producing more latex for several years (Heinz-Hermann 2000). Many other plants produce forms of latex rich in isoprene polymers, though not all produce usable forms of polymer as easily as the Para rubber tree does; some of them require more elaborate processing to produce anything like usable rubber, and most are more difficult to tap. Some produce other desirable materials, for example gutta-percha (Palaquium gutta) and chicle from Manilkara species. Others that have been commercially exploited, or at least have shown promise as sources of rubber, include the rubber fig (Ficus elastica), Panama rubber tree (Castilla elastica), various spurges (Euphorbia spp.), lettuce (Lactuca species), the related Scorzonera tausaghyz, various Taraxacum species, including common dandelion (Taraxacum officinale) and Russian dandelion (Taraxacum kok-saghyz) and guayule (Parthenium argentatum). The term gum rubber is sometimes applied to the tree obtained version of natural rubber in order to distinguish it from synthetic version (Heinz-Hermann 2000).



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Typically natural rubber contains a few percent of other materials, such as proteins, fatty acids, resins, and inorganic materials. Some natural rubber sources, called gutta percha, are composed of trans-1,4-polyisoprene, a structural isomer that has similar, but not identical, properties (Heinz-Hermann 2000). Table 2.1 shows the characteristics of Natural Rubber. Table 2.1. Natural Rubber Characteristic No. 1. 2. 3. 4. 5.



Characteristic Chemical composition SPGR Elasticity Tensile strength Abrasion resistant



6. Solubility 7. Physical appearance



Details Mainly cis-polyisoprene 0.915 Ranging from temperature 10-60oC Low Low Insoluble in water, alcohol, acetone, dilute acids, and alkalis Soluble in ether, carbon disulphide, carbon tetrachloride, petrol and turpentine Pure rubber is transparent, amorphous solid (Forrest 2001)



Rubber exhibits unique physical and chemical properties. Rubber’s stressstrain behaviour exhibits the Mullins effect and the Payne effect, and is often modelled as hyperelastic. Due to the presence of a double bond in each repeat unit, natural rubber is susceptible to vulcanisation and sensitive to ozone cracking (Heinz-Hermann 2000). On a microscopic scale, relaxed rubber is a disorganized cluster of erratically changing wrinkled chains. In stretched rubber, the chains are almost linear. The restoring force is due to the preponderance of wrinkled conformations over more linear ones. Cooling below the glass transition temperature still permits local conformational changes but a reordering is practically impossible because of the larger energy barrier for the concerted movement of longer chains. “Frozen” rubber’s



19



elasticity is low and strain results from small changes of bond lengths and angles. This caused the Challenger disaster, where flattened o-rings failed to relax to fill a widening gap. The glass transition is fast and reversible: the force resumes on heating (HeinzHermann 2000). The parallel chains of stretched rubber are susceptible to crystallization. This take some time because turns of twisted chains have to move out of the way of the growing crystallites. Crystallization has occurred, for example, when, after days, an inflated toy balloon is found withered at a relatively large remaining volume. Where it is touched, it shrinks because the temperature of the hand is enough to melt the crystals (Heinz-Hermann 2000). Vulcanization of rubber creates disulfide bond between chains, which limits the degrees of freedom and results in chains that tighten more quickly for a given strain, thereby increasing the elastic force constant and making the rubber harder and less extensible (Heinz-Hermann 2000). Polyisoprene can also be created synthetically, producing what is sometimes referred to as “synthetic natural rubber”, but the synthetic and natural routes are completely different (Heinz-Hermann 2000). Natural rubber is an elastomer and a thermoplastic. Once the rubber is vulcanized, it will turn into a thermoset. Most rubber in everyday use is vulcanized to a point where it shares properties of bot; i.e., if it is heated and cooled, it is degraded but not destroyed. The final properties of a rubber item depend not just on the polymer, but also on modifiers and fillers, such as carbon black, factice, whiting and a host of others (Heinz-Hermann 2000). Rubber particles are formed in the cytoplasm of specialized latex-producing cells called laticifiers within rubber plants (Ohya and Koyama 2001). Rubber particles



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are surrounded by a single phospholipid membrane with hydrophobic tails pointed inward. The membrane allows biosynthetic proteins to be sequestered at the surface of the growing rubber particle, which allows new monomeric units to be added from outside the biomembrane, but within the lacticifer. The rubber particle is an enzymatically active entity tat contains three layers of material, the rubber particle, a biomembrane, and free monomeric units. The biomembrane is held tightly to the rubber core due to the high negative charge along the double bonds of the rubber polymer backbone (Paterson-Jones, Gilliland and Van Staden 1990). Free monomeric units and conjugated proteins make up the outer layer. The rubber precursor is isopentenyl pyrophosphate (an allylic compound), which elongates by Mg2+-dependent condensation by the action of rubber transferase. The monomer adds to the pyrophosphate end of the growing polymer (Paterson-Jones, Gilliland and Van Staden 1990). The process displaces the terminal high-energy pyrophosphate. The reaction produces a cis polymer. The initiation step is catalyzed by prenyltransferase, which converts three monomers of isopentenyl pyrophosphate into farnesyl pyrophosphate. The farnesyl pyrophosphate can bind to rubber transferase to elongate a new rubber polymer (Xie, et al. 2008). The required isopentenyl pyrophosphate is obtained from the mevalonate pathway, which is derives from acetyl-CoA in the cytosol. In plants, isoprene pyrophosphate can also be obtained from 1-deox-D-xyulose-5-phosphate/2-C-methylD-erythritol-4-phosphate pathway within plasmids (Casey and Seabra 1996). The relative ratio of the farnesyl pyrophosphate initiator unit and isoprenyl pyrophosphate elongation monomer determines the rate of new particle synthesis versus elongation of existing particles. Though rubber is known to be produced by only one enzyme,



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extracts of latex have shown numerous small molecular weight proteins with unknown function. The proteins possibly serve as cofactors, as the synthetic rate decreases with complete removal (Kang, Kang and Han 2000). The two main solvents for rubber are turpentine and naphta (petroleum). The former has been in use since 174 when Francois Fresnau made the discovery. Giovanni Fabbroni is credited with the discovery of naphtha as a rubber solvent in 1779. Because rubber does not dissolve easily, the material is finely divided by shredding prior to its immersion. An ammonia solution can be used to prevent the coagulation of raw latex while it is being transported from its collection site (HeinzHermann 2000). Existing varied types of rubber have different degradation and solubility temperature based on the constituent compounds of each type, which was summarized in Table 2.2. Table 2.2. Degradation and Solubility Temperature of Some Rubber Type No . 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.



Rubber Type Polyurethane Natural rubber and polyisoprene Butadiene and styrene-butadiene Nitrile and polychloroprene Butyl styrene Silicone Chlorosulphonate polyetheylene Nitrile Fluorocarbon Polychloroisoprene Styrene-butadiene Ethylene-propylene



Maximum Temperature (oC) 80 80 100 120 130 above 100.000 above 100.000 above 100.000 above 100.000 above 100.000 above 500.000 above 500.000 (Forrest 2001)



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Even though the amount of natural rubber production and consumption is under that of synthetic rubber, its role still remains irreplaceable, considering the fact that tire production reasonably needed natural rubber. According to several studies, natural rubber content in vehicle tire can not be less than 35%, meaning that it is impossible to produce tire without natural rubber. As a result, nearly 70% of world’s natural rubber production is used to manufacture tire, while the rest is utilize in other product manufacturing. Natural rubber as raw material is an indispensable thing for downstream industries manufacturing process, since it can not be replaced 100% by synthetic rubber, which has many weak characteristics compared to that of natural rubber characteristic (Balitbang 2013). Rubber latex is extracted from rubber trees. The economic life period of rubber trees in plantations is around 32 years-up to 7 years of immature phase and about 25 years of productive phase. The soil requirement of the plant is generally well-drained, weathered soil consisting of laterite, lateritic types, sedimentary types, nonlateritic red, or alluvial soils (Cecil, et al. 2013). The climatic conditions for optimum growth of rubber trees are: 1. Rainfall of around 250 cm evenly distributed without any marked dry season and with at least 100 rainy days per year. 2. Temperature range of about 20 to 34oC, with a monthly mean of 25 to 28oC. 3. High atmospheric humidity of around 80%. 4. Bright sunshine amounting to about 2000 hours per year at the rate of six hours per day throughout the year.



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5. Absence of strong winds. Many high-yielding clones have been developed for commercial planting. These clones yield more than 2,000 kg of dry rubber per hectare per year, when grown under ideal conditions (Cecil, et al. 2013). Natural rubber excellence properties that can not be vied when compared to synthetic rubber are (Badri 2013): 1. Perfect elasticity and resilience 2. Good plasticity making it easier to be treated 3. High wear resistance 4. Low heat build up 5. High groove cracking resistance 6. Able to be formed with low heat 7. High glutinous to many kinds of material These excellence properties make natural rubber difficult to be compared with synthetic rubber, causing natural rubber as the highest component contained in off road and aeroplane tire manufacturing (Balitbang 2013). Natural rubber can also be used either as an intermediate or raw material for other rubber based materials production. There are some widely known natural rubber varieties, such as (Badri 2013):



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a. b. c. d. e. f. g.



Rubber material (plantation latex, wind sheet, thin slab, fresh lump) Conventional rubber (RSS, white crepes, and pale crepe) Thick latex Block rubber (SIR 5, SIR 10 and SIR 20) Crumb rubber Tire rubber Reclaimed rubber Latex is generally processed into either latex concentrate for manufacture of



dipped goods or it can be coagulated under controlled, clean conditions using formic acid. The coagulated latex can then be processed into the higher-grade, technically specified block rubbers such as SVR 3L or SVR CV or used to produce Ribbed Smoke Sheet grades (Dick 2003). Naturally coagulated rubber (cup lump) is used in the manufacture of TSR10 and TSR20 grade rubbers. The processing of the rubber for these grades is a size reduction and cleaning process to remove contamination and prepare the material for the final stage of drying. The dried material is then bales and palletized for storage and shipment in various methods of transportation (Dick 2003). 2.2.2. Isoprene The polyisoprene part of natural rubber thermally decomposes through a βscission mechanism to an isoprene intermediate radical. It is then transformed to isoprene (depropagation) (Pakdel, Pantea and Roy 2001). Isoprene that is also known as 2-methyl-1,3-butadiene, is a common organic compound with the formula CH2=C(CH3)CH=CH2. It is a colorless volatile liquid and one of the most important non-methane hydrocarbons in the atmosphere (Guenther, et al. 2006).



Figure 2.2. Isoprene Chemical Structural



25



Isoprene is produced and emitted by many species of trees into the atmosphere, which major producers are oaks, poplars, eucalyptus, and some legumes. Its emissions from vegetation constitute ~40% of the total mass of non-methane hydrocarbon compounds emitted to the atmosphere. The yearly production of isoprene emissions by vegetation



is



around



600



million



tonnes,



with



half



of



that



coming



from tropical broadleaf trees and the remainder coming from shrubs (Guenther, et al. 2006). This is about equivalent to methane emission into the atmosphere and accounts for approximately one-third of all hydrocarbons released into the atmosphere. After release, isoprene is converted by free radicals (like the hydroxyl (OH) radical) and to a lesser extent by ozone into various species, such as aldehydes, hydroperoxides, organic nitrates, and epoxides, which mix into water droplets and help create aerosols and haze. Atmospheric reactions of isoprene involve several thousand subsequent reactions and hundreds of intermediate species (Daily 2009). Table 2.3. Isoprene Chemical Properties Properties Molecular formula C5H8 Molar mass 68.12 g/mol Density 0.681 g/cm3 Melting point -143.95oC Boiling point 34.067oC *Except where noted otherwise, data are given for materials in their standard state (at 25oC (77oF), 100 kPa) A second major effect of isoprene on the atmosphere is that in presence of nitric oxides (NOx) it contributes to the formation of tropospheric (lower atmosphere) ozone, which is one of the leading air pollutants in many countries. Isoprene itself is normally not regarded as a pollutant, as it is one of the natural products from plants.



26



Formation of tropospheric ozone is only possible in presence of high levels of NOx, which comes almost exclusively from industrial activities. In fact, isoprene can have the opposite effect and quench ozone formation under low levels of NOx.Isoprene is made through the methyl-erythritol 4-phospate pathway (MEP pathway, also called the non-mevalonate pathway) in the chloroplasts of plants. One of the two end products of MEP pathway, dimethylallyl diphosphate (DMADP), is catalyzed by the enzyme isoprene synthase to form isoprene. Therefore, inhibitors such as fosmidomycin that block the MEP pathway also blocks isoprene formation. Isoprene emission increases dramatically with temperature and maximizes at around 40°C. This has led to the hypothesis that isoprene may protect plants against heat stress. Emission of isoprene is also observed in some bacteria and this is thought to come from non-enzymatic degradations from DMADP. Isoprene emission in plants is controlled both by the availability of substrate (DMADP) and by enzyme (isoprene synthase) activity. In particular, light, CO2 and O2 dependencies of isoprene emission are controlled by substrate availability, whereas temperature dependency of isoprene emission is regulated both by substrate level and enzyme activity. The emission of isoprene appears to be a mechanism that trees use to combat abiotic stresses. It was proposed that isoprene emission was specifically used by plants to protect against large fluctations in leaf temperature (Sharkey, Wiberley and Donohue 2007). Isoprene is incorporated into and helps stabilize cell membranes in response to heat stress, conferring some tolerance to heat spikes. Isoprene also confers resistance to reactive oxygen species (Vickers, et al. 2009). The amount of isoprene released from isoprene-emitting vegetation depends on leaf mass, leaf area, light (particularly photosynthetic photon flux density, or PPFD), and leaf temperature. Thus, during the night, little isoprene is emitted from tree leaves, whereas daytime emissions are



27



expected to be substantial during hot and sunny days, up to 25 μg/(g dry-leafweight)/hour in many oak species (Benjamin, et al. 1996). Isoprene also exist in other living organism, as an example it is the most abundant hydrocarbon measurable in the breath of humans, The estimated production rate of isoprene in the human body is 0.15 µmol/(kg·h), equivalent to approximately 17 mg/day for a person weighing 70 kg. Isoprene is also common in low concentrations in many foods (Gelmont, Stein and Mead 1981). The isoprene skeleton can be found in naturally occurring compounds called terpenes, but these compounds do not arise from isoprene itself. Terpenes can be viewed as multiples of isoprene subunits, and this perspective is the cornerstone of the "isoprene rule". The precursor to isoprene units in biological systems are dimethylallyl diphospate (DMADP) and its isomer isopentenyl diphosphate (IDP). The plural “isoprenes” is sometimes used to refer to terpenes in general. Isoprene chains are commonly found in numerous biologically active oligomers such as Vitamin A (HeinzHermann 2000). In industrial production, isoprene was first isolated by thermal decomposition of natural rubber (Williams 1860). It is most readily available industrially as a byproduct of the thermal cracking of naphta or oil, as a side product in the production of ethylene. About 800,000 tonnes are produced annually. About 95% of isoprene production is used to produce cis-1,4-polyisoprene—a synthetic version of natural rubber (Heinz-Hermann 2000). Isoprene is a common structural motif in biological systems. The isoprenoids (for example, the carotenes are tetraterpenes) are derived from isoprene. Also derived from isoprene are phytol, retinol (vitamin A), tocopherol (vitamin E), dolichols, and squalene. Heme A has an isoprenoid tail, and lanosterol, the sterol



28



precursor in animals, is derived from squalene and hence from isoprene. The functional isoprene units in biological systems are dimetyhlallyl diphosphate (DMADP) and its isomer isopentenyl diphosphate (IDP), which are used in the biosynthesis of naturally occurring isoprenoids such as carotenoids, quinones, lanosterol derivatives (e.g. steroids) and the prenyl chains of certain compounds (e.g. phytol chain of chlorophyll) (Heinz-Hermann 2000). Treatment of isoprene (2-methyl-1,3-butadiene) with catalytic amounts of acid leads to a variety of oligomeric products, one of which is limonene: Two molecules of isoprene may also be converted into limonene by a completely different mechanism, which takes place in the strict absence of catalysts of any kind. 2.2.3. Limonene Diels-Alder mechanism is postulated for the formation of dl-limonene, which will decompose above 450oC if it is not quickly removed from the reaction zone (Pakdel, Pantea and Roy 2001). Limonene is a colourless liquid hydrocarbon classified as a cyclic terpene. The more common D-isomer possesses a strong smell of oranges. It is used in chemical synthesis as a precursor to carvone and as a renewably based solvent in cleaning products (Guenther, et al. 2006).



Figure 2.3. Limonene Chemical Structure



29



Limonene takes its name from the lemon, as the rind of the lemon, like other citrus fruits, contains considerable amounts of this compound, which contributes to their odor. Limonene is a chiral molecule, and biological sources produce one enantiomer: the principal industrial source, citrus fruit, contains D-limonene ((+)limonene), which is the (R)-enantiomer (CAS number 5989-27-5, EINECS number 227-813-5). Racemic limonene is known as dipentene. D-Limonene is obtained commercially from citrus fruits through two primary methods: centrifugal separation or steam distillation (Simonsen 1947). Table 2.4. Limonene Chemical Properties



Properties IUPAC name



1-methyl-4-(1-methylethenyl)-cyclohexene



Other name



4-isopropenyl-1-methylcyclohexene



Molecular Formula



C10H16



Molar Mass



136.23 g/mol



Density



0.8411 g/cm3



Melting Point



-74.35oC, -101.83oF, 198.80 K



Boiling Point



176oC, 349oF, 449 K



Chiral Rotation [α]D



87o-102o



Hazards R-phrases



Flammable, Irritating to Skin, May Cause Sensitisation by Skin, Very Toxic to Aquatic Organisms, May Cause Long-term Adverse Effects



30



in the Aquatic Environment



S-phrases



Keep Out of the Reach of Children, Avoid Contact with Skin, Wear Suitable Gloves, This Material and Its Container Must be Disposed of as Hazardous Waste, Avoid Release to the Environment, Refer to Special Instructions/Safety Data Sheet



Flash Point



50oC, 122oF, 323 K



*Except where noted otherwise, data are given for materials in their standard state (at 25oC (77oF), 100 kPa)



Limonene is a relatively stable terpene and can be distilled without decomposition, although at elevated temperatures it cracks to form isoprene (Pakdel, Pantea and Roy 2001). It oxidizes easily in moist air to produce carveol, carvone, and limonene oxide. With sulfur, it undergoes dehydrogenation to p-cymene. Limonene occurs naturally as the (R)-enantiomer, but racemizes to dipentene at 300°C. When warmed with mineral acid, limonene isomerizes to the conjugated diene α-terpinene (which can also easily be converted to p-cymene). Evidence for this isomerization includes the formation of Diels-Alder adducts between α-terpinene adducts and maleic anhydride (Karlberg, Magnusson and Ulrika 1992). It is possible to effect reaction at one of the double bonds selectively. Anhydrous hydrogen chloride reacts preferentially at the disubstituted alkene, whereas epoxidation with MCPBA occurs at the trisubstituted alkene. In another synthetic method Markovnikov addition of trifluoroacetic acid followed by hydrolysis of the acetate gives terpineol. Limonene is formed from geranyl pyrophosphate, via



-H+ geranyl pyrophosphate



31



cyclization of a neryl carbocation or its equivalent as shown. The final step involves loss of a proton from the cation to form the alkene (Mann, et al. 1994).



OPP



Figure 2.4. Limonene Derivation The most widely practiced conversion of limonene is to carvone. The three step reaction begins with the regioselective addition of nitrosyl chloride across the trisubstituted double bond. This species is then converted to the oxime with base, and the hydroxylamine is removed to give the ketone-containing carvone (Fahlbusch, et al. 2003). Limonene is common in cosmetic products. As the main odor constituent of citrus (plant family Rutaceae), D-limonene is used in food manufacturing and some medicines, e.g. as a flavouring to mask the bitter taste of alkaloids, and as a fragrant in perfumery; it is also used as botanical insecticide, particularly the (R)-(+)enantiomer is most active as an insecticide. It is added to cleaning products such as hand cleansers to give a lemon-orange fragrance (see orange oil) and because of its ability to dissolve oils. In contrast, L-limonene has a piney, turpentine-like odor. In natural and alternative medicine, D-limonene is marketed to relieve gastroesophageal reflux disease and heartburn (Sun 2007). Limonene is increasingly being used as a solvent for cleaning purposes, such as the removal of oil from machine parts, as it is produced from a renewable source (citrus oil, as a byproduct of orange juice manufacture). It is used as a paint



32



stripper and is also useful as a fragrant alternative to turpentine. Limonene is also used as a solvent in some model airplane glues. All-natural commercial air fresheners, with air propellants, containing limonene are used by philatelists to remove self-adhesive postage stamps from envelope paper (Butler 2010). Limonene is also finding increased use as a solvent for filament-fused 3D printing. Printers can print the plastic of choice for the model, but erect supports, and binders from HIPS, a polystyrene plastic, that are easily solvable in Limonene. As it is combustible, limonene has also been considered as a biofuel (Congress 2007). In preparing tissues for histology or histopathology, D-limonene is often used as a less toxic substitute for xylene when clearing dehydrated specimens. Clearing agents are liquids miscible with alcohols (such as ethanol or isopropanol) and with melted paraffin wax, in which specimens are embedded to facilitate cutting of thin sections for microscopy. Limonene is adenosine agonist which may explain its antistress and sedative properties (Wynnchuk 1994). Limonene and its oxidation products are skin and respiratory irritants, and limonene-1,2-oxide (formed by aerial oxidation) is a known skin sensitizer. Most reported cases of irritation have involved long-term industrial exposure to the pure compound, e.g. during degreasing or the preparation of paints. However, a study of patients presenting dermatitis showed that 3% were sensitized to limonene (Cancer 1999). Although high doses have been shown to cause renal cancer in male rats, limonene is considered by some researchers to be a potential chemopreventive agent with value as a dietary anti-cancer tool in humans (Tsuda, et al. 2004). There is no evidence for carcinogenicity or genotoxicity in humans. The IARC classifies Dlimonene as a Group 3 carcinogen: not classifiable as to its carcinogenicity to humans.



33



No information is available on the health effects of inhalation exposure to D-limonene in humans, and no long-term inhalation studies have been conducted in laboratory animals. D-Limonene is biodegradable, but due to its low flash point, it must be treated as hazardous waste for disposal (Cancer 1999). 2.2.4. Catalyst and Support Material A. Catalyst A catalyst is defined as a material that accelerates a chemical reaction but remains unchanged chemically in the process. For a reaction to be possible, the process must be accompanied by a decrease of free energy. The reduction in activation energy is achieved by the catalyst providing an alternative pathway of lower energy for the reaction. Often products are formed in addition to those that are desired. The selectivity of a catalyst is a measure of the catalyst’s ability to direct the conversion to the desired products. The greater the stability of a catalyst, the lower the rate at which the catalyst loses its activity or selectivity or both. Generally, catalysts consist of two or more components: the support and one or more active phases. The phase is principally responsible for the catalytic activity, whilst the support provides a vehicle for the active phase. The activity of a catalyst has been related to the number of active (acid) sites on the catalyst surface. Strong acids come in two fundamental types, Brønsted and Lewis acids. Brønsted acidity is provided by the very active hydrogen ion (H+), which has a high positive charge density and seeks out negative charge, such as pi-electrons in aromatic centres. Brønsted acids can add to an olefinic double bond to form a carbocation. Lewis acids have high positive charge densities and can abstract a hydride ion from a saturated hydrocarbon, forming a carbenium ion. Catalysts employed in the petrochemical industry include amorphous silica-alumina (SiO2/Al2O3), zeolites, acid-activated clays, and aluminium chloride (AlCl3), amongst others. B. Support Material



34



1.



Aluminosilicates Aluminium is about the same size as silicon and readily substitutes for the latter in nature. However, since aluminium is a 3+ ion and silicon is 4+, an additional cation is required for charge balance. Thus, a Si4+ in the silicate framework can be substituted by the combination of an Al3+ with an additional (non-framework) ion. Aluminosilicates incorporating aluminium (Al), silicon (Si) and oxygen (O) find wide



2.



application as industrial catalysts. Zeolites Zeolites consist of atoms or ions arranged in a periodic array and are structurally unique in having cavities or pores with molecular dimensions, as part of their crystalline structures, which bear catalytic sites. In zeolite ZSM-5, some of the silicon atoms in the SiO4 tetrahedral are replaced by Al atoms. The tetrahedral are linked to form a chain-type building block, which are then connected to other chains. Rings consisting of 10 oxygen atoms provide access to a network of intersecting pores within the crystal. Many molecules are small enough to penetrate into this intracrystalline pore structure, where they may be catalytically converted. The aluminosilicate structure is ionic, incorporating Si 4+, Al3+ and O2- ions. When some of the Si4+ ions in the SiO4 tetrahedra are replaced by Al3+ ions, an excess negative charge is generated. To compensate for this negative charge, positive ions (cations) must be added to the framework Si4+ and Al3+. These non-framework cations play a central role in determining the catalytic nature of the zeolite. Faujasites consist of 12-membered oxygen rings (0.74 nm apertures) and a three dimensional pore structure, and are able to admit hydrocarbon molecules larger than naphthalene. For this reason, faujasites have applications in the catalytic cracking of petroleum molecules into smaller gasoline-range molecules. Faujasites are made of sodalite cages – twenty-four primary building blocks of SiO 4 and AlO4 tetrahedral in a truncated octahedron – arranged in a regular array. Each sodalite cage is connected to



35



four other sodalite cages, with each connecting unit made of six bridging oxygen ions linking the hexagonal faces of two sodalite units. The supercage in faujasites, surrounded by 10 sodalite units, is large enough to contain a sphere of diameter 1.2 nm. Figure 2.5. displays the structure of faujasite.



Figure 2.5. Structure of faujasite a.



Adsorption in Zeolites The void spaces in the crystalline structures of zeolites provide a high capacity for adsorbates. Chemisorption of polar molecules is influenced strongly by the nature of the cations and the interactions between the cations and guest molecules. Guest molecules can change the configuration of the aluminosilicate framework slightly. Adsorption in the pores cannot take place unless the guest molecules are small enough



b.



to fit through the apertures, and can be hindered by the cations. Aluminium Content The ion exchange capacity of a zeolite is equal to the concentration of Al 3+ ions, therefore the structures with low Si/Al ratios are able to have higher concentrations of catalytic sites than the zeolites with high Si/Al ratios. However, the stability of the crystal framework increases with increasing Si/Al ratios. Table 2.5. lists the Si/Al ratios for four different types of zeolites. Table 2.5. Si/Al ratios for four types of zeolite Zeolites



Name



Si/Al Ratio



Zeolite A



LTA



1



36



c.



Zeolite Y



FAU



≈ 2.5



Mordenite



MOR



≈5



ZSM-5



MFI



> 12



Acidity of Zeolites Both Brønsted and Lewis acid sites occur in zeolites. The hydrogen form zeolite contains protons (H+) that are mobile within the structure. OH groups located near AlO4- tetrahedra are thought to be strong Brønsted acids, but are said to have a wide distribution of proton donor strengths (Cejka, Zones and Corma 2010). Zeolites with low densities of proton donor groups, such as HZSM-5 and ultra-stable HY, have been found to have high proton donor strengths, with the highest strengths associated with AlO4- tetrahedra having the smallest number of Al neighbours. When a hydrogen form zeolite is heated to high temperatures, water is driven off and coordinatively unsaturated Al3+ ions are formed. These are strong Lewis acids, with one Lewis acid



d.



site formed from two Bronstedt acid sites. Selectivity of Zeolites Zeolite catalysts often have a high selectivity for the following class of reaction: olefins + cycloparaffins → paraffins + aromatics which is accounted for by hydrogen (hydride and proton) transfers. This makes zeolites important catalysts in the cracking of heavier petroleum fractions into smaller paraffins and olefins that boil in the gasoline range. Chatterjee et al. (1999) studied the interaction energy between organic molecules (reactant and product) and the zeolite host lattice to locate the reason for the selectivity order. It was found that the positive charges in the molecules have ionic interactions with the basic oxygen of the zeolite framework, allowing adsorption inside the zeolite void volume. The void dimensions of the zeolite were said to control product yield, whilst the electronic interactions played a vital role in the mechanism of the organic reaction.



37



(Woo, Lee and Lee 1996) investigated the catalytic skeletal isomerisation of nbutenes to iso-butene over a natural clinoptilolite zeolite. It was found that proton exchange was essential for the zeolite to have isomerisation activity. The exchange created strong acid sites, with a zeolite of Si/Al ratio of 20 exhibiting greater activity than a zeolite with Si/Al ratio of 10. Buchanan studied the effects of adding ZSM-5 to fluid catalytic cracking (FCC) units. The zeolite was found to catalyse C 5+ olefin isomerisation, with ZSM-5 prepared with higher silica/alumina ratio exhibiting higher gasoline selectivity.



3.



Clays Clay minerals are found in soils, sediments and rocks and are classified as phyllosilicates (hydrous aluminosilicates). Generally, they are said to be composed of particles less than 2 μm in size. The vast majority of clays are aluminosilicates or magnesiosilicates, and consist of repeating layers of silicate [SiO 4]4- sheets (tetrahedral) and metal oxide sheets (octahedral) bonded together via shared oxygen atoms and combined in T:O (1:1) or T:O:T (2:1) arrangements, as shown in Figure 2.6. below.



Figure 2.6. T:O and T:O:T arrangements in clays



38



The 1:1 arrangement of alternating tetrahedral and octahedral sheets uses hydrogen bonds between the —OH on one layer and a bridging —O— on the next layer as the main bonding force between layers. Smectities (e.g. montmorillonite) are composed



of



the



2:1



arrangement



of



repeating



units



of



tetrahedral:octahedral:tetrahedral layers. If the layers are neutral and are simply held together by van der Waals forces (e.g. talc), then the layers can easily slip over one another.



C. The Heating of Catalysts In a zeolite, the aluminosilicate framework and the separate water molecules are held together by strong bonds, but the bond between the water molecules and the framework is relatively weak. Consequently, on heating to temperatures of approximately 100°C, water molecules are lost from the zeolite, without affecting the framework structure. Liengme and Hall (1966) stated that maximum activity for the zeolite was achieved when all residual hydroxyl groups associated with catalytically active sites were removed. Uytterhoeven, Christner and Hall (1965) found that during this process, both Brønsted and Lewis sites were present on the silica-alumina surface, with Brønsted sites making up only a small portion of the surface hydroxyl groups. On heating a clay, desorption of H2O on exterior surfaces and dehydration of interlayer H2O occurs at low temperatures (< 100°C) (Guggenheim and Koster van Groos 2001). This endothermic effect is accompanied by a loss of mass as the absorbed water is removed. The second endothermic effect involves the removal of the hydroxyl groups from the lattice of the mineral in the form of water vapour. For montmorillonite, this is said to occur from 670°C to 710°C. On heating, kaolinite was found to show an



39



endothermic effect at 560°C and two exothermic effects with maxima at 960°C and 1,250°C, with a total weight loss of 14% (Korneva and Yusupov 1976). Heating a clay is known to increase the Brønsted and Lewis acidity. However, care must be taken when dehydrating the clay as heating can cause layer collapse through layer crosslinking, along with elimination of water (ceramification). Depending on the degree of order, hydrogen bonding and layer spacing, ceramification of a clay occurs between 300°C and 700°C. D. Catalyst Preparation Catalytic materials exist in various forms and their preparation involves different protocols with a multitude of possible preparation schemes, many times larger than the number of known catalysts. Moreover, preparation of any catalyst involves a sequence of several complex processes, many of them not completely understood. As a result, subtle changes in the preparative details may result in dramatic alteration in the properties of the final catalyst (Schwarz 1995). The goal of a catalyst manufacturer is to produce and reproduce a commercial product which can be used as a stable, active, and selective catalyst. To achieve this goal, the best preparative solution is sought which results in sufficiently high surface area, good porosity, and suitable mechanical strength. The first of these, surface area, is an essential requirement in that reactants should be accessible to a maximum number of active sites. The properties of a good catalyst for industrial use may be divided, at least for the purpose of easy classification, into two categories (Schwarz 1995): 1. Properties which determine directly catalytic activity and selectivity, here such factors as bulk and surface chemical composition, local microstructure, and phase composition are important



40



2. Properties which ensure their successful implementation in the catalytic process, here thermal and mechanical stability, porosity, shape, and dimension of catalyst particles enter. The requirements which are fundamental for catalyst performance generally require a compromise in order to produce a material which meets the contradictory demands imposed by industrial processes. An acceptable solution is typically ascertained by a trial-and-error route. Catalytic materials become catalysts when they are used in industrial processes. A way this can be realized occurs when the variety of methods used to prepare catalytic materials are viewed in relation to their successful implementation in commercial applications (Schwarz 1995). Figure 2.7. is a simplified diagram which summarizes the traditional methods used for the preparation of heterogeneous catalysts. The vertical ordering takes into account the fact that the final catalyst is a solid phase with new properties which have to be acquired and stabilized during the preparation process while the horizontal delineation depicts the various methods for “blending“ and “mounting” to produce the catalytic material. A noticeable discontinuity does develop here, however, because some preparative procedures can fit into both cases. In Figure 2.7. two preparation routes define the extremes of traditional procedures used in catalyst preparation: precipitation (with the variant of coprecipitation) and impregnation (with such variants as ion exchange, deposition, and grafting). In the precipitation route, a new solid phase is obtained by the "blending of proper reagents (precipitating agents) from a liquid medium; the resulting precipitate is transformed in subsequent preparation stages into the active catalyst. During these transformations, both the mechanical properties of the catalyst and those intrinsically related to the catalysts' performance have to be considered simultaneously. In contrast, in the impregnation route, a solid phase



41



preformed in a separate process is used as a support, and the catalytically active material is "mounted" and stabilized on it. In this way, at least a part of the mechanical properties of the final catalyst'are controlled by the preexisting support, and the preparation process is basically focused on the introduction of the catalytic compound(s) (Schwarz 1995).



TRANSFORMING MOUNTING



BLENDING



ACTIVE PRECURSOR



LIQUID



LIQUID of SOLID SOLID



LIQUID



IN VAPORS SOLUTION SOLID PHASE SOLID



SOLID



Precipitation



Co-Precipitation



Complexion



Gelatin



Firing



Kneading



Heating



Evaporating



Metals Deposition Chemical Reaction Thin Films



Colloidal Adsorption Grafting



Bulk



Amorphous Ion exchange



Crystallization INCIPIENT SOLID FORMATION



SOLVENT REMOVAL (optional) and SOLID STATE REACTIONS



REACTIONS ON THE SURFACE OF PREFORMED SUPPORT



MECHANICAL PROCEDURES (optional)



ACTIVATION BY THERMOCHEMICAL PREFORMED SUPPORT PROCEDURES



FINAL CATALYST



Figure 2.7. Simplified Diagrams Summarizing Methods of Blending, Transforming and Mounting Catalytic Components Between these two extremes there lies methods which are best characterized as solid transformation. Here physical and chemical processes are used to reconstruct a



42



solid into a form that meets the demands imposed by the processes in which they will be used (Schwarz 1995). There are only two main routes for the preparation of almost all catalysts. These can be divided into the two categories: methods in which the catalytically active phase is generated as a new solid phase by either precipitation or a decomposition reaction, and methods in which the active phase is introduced and fixed onto a preexisting solid by a process which is intrinsically dependent on the surface of the support (Schwarz 1995). The simplest kinds of catalysts, from a structural point of view, are single phase catalysts, such as bulk metals and alloys, bulk oxides, sulfides, carbides, borides, and nitrides. These materials are, more or less, uniform solids at the molecular level that exhibit catalytic properties on their external surface. Therefore, these materials are preferably used in a physical form which allows for a maximum development of contact of the surface of the material with its environment. To this end, preparation methods are selected which avoid excessive heat treatments which would result in the system acquiring a more stable lower surface energy state at the expense of its active surface (Schwarz 1995). Bulk oxide catalysts, either single metal or multimetal, used in industrial processes are usually in the form of powders, pellets, or tablets, with either amorphous or polycrystalline structure. The most common method used for preparation of bulk oxide catalysts is the (co)precipitation of a precursor phase, followed by thermal transformation that leads to the oxidic phase. The ceramic method involving grinding and firing mixtures of oxides is not very convenient for preparation of oxide catalyst because of the high temperatures needed. Thus, the trend in the development of preparation methods has witnessed efforts to eliminate the high-temperature treatments of the coprecipitated materials (such as calcination of mixtures of



43



hydroxides and decomposition to oxides) which affect the solid state reactions that produce the intimately mixed oxide phase that acts as a catalyst. Several alternative preparation routes that enable a better mixing of the components have been proposed (Schwarz 1995). A method of continuous homogeneous precipitation was developed, wherein the precipitating agent (hydroxyl ions in the classical coprecipitation method) is slowly and continuously generated in the synthesis medium by a controlled hydrolysis process (such as hydrolysis of urea). The advantage of slow precipitation is a more efficient mixing of the components in the precipitated product. The solgel method, although related to the coprecipitation method, provides better control of the texture of the resulting catalyst and ensures an increased uniformity of the product. The method consists in formation of a colloidal dispersion of the metal constituents, usually by hydrolysis of metal alkoxides. The colloidal solution is then subjected to gelation by either changing the pH, the temperature, or the electrolyte. The resulting gel is then heat treated to remove the solvent. Decomposition of coordination compounds, including polynuclear compounds, is another preparative route that starts from a precursor where the metallic elements are intimately mixed at the molecular or at the atomic level. Among the metal complexes that can be decomposed at relatively low temperatures are oxalates, formates, citrates, and carbonyls (Schwarz 1995). Bulk sulfide catalysts and mixed sulfide catalysts are prepared most commonly by either direct sulfidation (i.e., reaction with hydrogen sulfide) of oxides, halides, or other metal salts. The direct method may require the use of high temperatures. A second variant is the decomposition of a sulfur-containing precursor, such as a thiosalt, which is obtained by low-temperature precipitation. A type of low-temperature coprecipitation is homogeneous sulfide precipitation, wherein the mixing of the metal salts is made before any addition of the precipitant. Recently, a new genre of single



44



phase catalysts has emerged in which the entire solid rather than just the external surface is involved in catalysis. The new materials are crystalline solids which contain active sites uniformly distributed throughout their bulk at the intracrystalline level. This family of uniform heterogeneous catalysts, generally referred to as molecular sieves, includes microporous zeolites, aluminium phosphates, with metal- and siliconsubstituted analogs, layered compounds such as clays and their pillared variants, layered oxides with perovskite structures, and heteropolyacids with a liquid-like behaviour (Schwarz 1995). The possibilities for preparation of materials in this class are vast since they exploit the virtually unlimited number of ways to link together atomic units in a crystalline or polymeric structure. Their methods of preparation consist of a combination of chemical (precipitation, leaching) and physical (supercritical crystallization) procedures. The common features of all the preparation methods summarized above for bulk catalytic materials is the use of traditional methods and techniques from preparative chemistry, such as precipitation, hydrolysis, and thermal decomposition. The chemistry involved during these preparation steps does not differ much from that taught in classical handbooks of analytical or inorganic chemistry. These processes involve mixing of solutions, blending of solids, precipitation, filtration, drying, calcination, granulation, tableting, and extrusion. In other words, the chemistry involved is three dimensional with the meaning that it is isotropic with respect to the container in which it is done (Schwarz 1995). The method of precipitation is the best known and most widely used procedure for synthesis of both monometallic and multimetallic oxides. Precipitation results in a new solid phase (precipitate), that is formed discontinuously (i.e., with phase separation) from a homogeneous liquid solution. A variety of procedures, such as addition of bases or acids, addition of complex-forming agents, and changes of



45



temperature and solvents, might be used to form a precipitate. The term coprecipitation is usually reserved for preparation of multicomponent precipitates, which often are the precursors of binary or multimetallic oxidic catalysts. The same term is sometimes improperly used for precipitation processes which are conducted in the presence of suspended solids (Schwarz 1995). Depending on the particular application, the newly formed solid phase may be further subjected to various treatments, such as aging and hydrothermal transformation, washing, filtration, drying, grinding, tableting, impregnation, mixing, and calcination. During all these preparative steps, physicochemical transformations occur which can profoundly affect the structure and composition of the catalyst surface and even its bulk composition. If the adage the catalyst “remembers” how it was prepared, even after being subjected to various heat treatments at elevated temperatures is valid, then any cause-and effect correlations that can eventually be made between the precipitation procedures and the final characteristics of the catalyst becomes significant (Schwarz 1995). a. Precipitation The formation of the precipitate from a homogeneous liquid phase may occur as a result of physical transformations (change of temperature or of solvent, solvent evaporation) but most often is determined by chemical processes (addition of bases or acids, use of complex forming agents). In almost all cases, the formation of a new solid phase in a liquid medium is resulted from two elementary processes which occur simultaneously or sequentially (Schwarz 1995): (1) nucleation, i.e., formation of the smallest elementary particles of the new phase which are stable under the precipitation conditions (2) growth or agglomeration of the particles



46



It is stressed in the importance of supersaturation, among other factors such as pH, temperature, nature of reagents, presence of impurities, and method of precipitation in determining the morphology, the texture and the structure of the precipitates. For example, under conditions of high supersaturation, the rate of nucleation of solid particles is much higher than the rate of crystal growth and leads to the formation of numerous but very small particles. Under the condition when the critical nucleation size is very small, only a metastable and poorly organized phase can develop; this may further change to a more stable phase during the hydrothermal treatment of the precipitates. Obtaining high supersaturation conditions is a difficult task in practice because of the natural evolution of the system toward a decrease of supersaturation by nucleation of solid particles and consumption of reagents. High levels of supersaturation can only be obtained for a short time and within limited volumes of solution. The problem of obtaining a homogeneous precipitate with respect to the size and structure of the particles reduces to that of achieving a uniformly high level of supersaturation throughout the liquid before the nucleation starts, which may be quite difficult because of mass and heat transport imitations. The chemical and physical properties of the precipitates kept in contact with their mother liquor may change, often substantially, due to secondary processes taking place in the suspension. One of these processes, known as Ostwald ripening, leads to an increase in the particle size of a precipitate. Because the solubility increases with decreasing particle size, small particles begin to dissolve and large crystals continue to grow (Schwarz 1995). Another process which takes place during aging of precipitates is agglomeration of colliding particles as a result of either Brownian motion or imposed mechanical forces. The most common catalysts derived from precipitation are aluminas. In order to emphasize the significance of the variables described above on the physicochemical



47



properties of the finished material, we will devote some effort to outline the procedures used to formulate aluminas. Because of its industrial importance, the preparation of aluminas of controlled porosity and surface area continues to be the focus of a large number of investigations (Schwarz 1995). Studies on the preparation of alumina in the absence of additives showed that the pore size distribution and the surface area are determined mainly by conditions of precipitation and aging. Development of these properties is due to the interconversion of amorphous hydroxide, pseudoboehmite, and bayerite formed during precipitation. Washing and drying were found to have little influence on texture for samples precipitated from ammonia and aluminum nitrate but contributed to the enlargement of pores when NaOH was used in precipitation. More control is possible by the use of additives. Alcohols added before precipitation of aluminum hydroxides only had an effect on the pore size when their adsorption on the precipitate was strong enough to replace the “solvent barrier” at the surface of precipitates. With these additives, the solubility of precipitates is decreased, leading to decreased Ostwald ripening and thus encouraging aggregation by particle bridging. Alcohol washing after precipitation produces higher surface areas and higher mesoporosity due to lower surface tension and less pore collapse during calcination (Schwarz 1995). The thermal and physical characterization of the conversion of pseudoboehmite to γ-Al2O3 were reviewed: and the relationship with the manufacturing route of the pseudoboehmite powder was shown. In general, physical properties like particle size and shape, crystallinity, and porosity have a distinct influence on the thermal behavior of pseudoboehmite powders. Better characterization of thermal and physical properties has allowed one to improve catalyst manufacturing at the industrial level. Unit operations



48



such as mix-mulling, extrusion, drying, and calcination are clearly affected by powder characteristics (Schwarz 1995). The calcination step may induce further changes in the texture of the finished supports. Under conventional operation conditions, γ-Al2O3 is stable, but at temperatures between 1250 and 1350 K a phase transformation through metastable δ- and Ɵ-Al2O3 leads to formation of α-Al2O3. The process is accelerated by steamll and results in a drastic drop in surface area which is caused by sintering of primary particles. The versatility of alumina to be produced with a broad range of surface areas and pore size distributions is in part due to the phase transformations during calcination. A systematic study of aluminum oxides obtained by heat treating of γ-Al 2O3 showed that a monodisperse structure is preserved below 1375 K, with a slight increase in the average pore radius. Formation of the α-Al2O3 phase is related to the generation of a new system of wider pores that again becomes monodispersed when the α-phase is completely formed. A relationship between porosity and mechanical strength was proposed for alumina catalyst (Schwarz 1995). A number of studies report methods to increase the thermal stability of γ-Al 2O3 particles by introducing various additives. The subject was recently reviewed in relation to preparation of stable materials for high temperature combustion. For example, it was reported that several ions (In3+, Ga3+, and Mg2+) have an accelerating influence while others (Zr4+,Ca2+, Th4+, La3+) have an inhibiting action during the transformation of aluminas to the α-phase. The effect of thermal stabilizing modifiers is due to surface nucleation of stable compounds, which by interaction with the underlying alumina, results in the formation of an aluminate surface layer which prevents transformation of γ to α alumina but may also modify the Lewis acidity of alumina. According to other results, addition of alkaline earth metals (Ca, Sr, Ba) increased the ability to preserve a high



49



surface area (≥5 m2 g-l) after calcination at 1700 K. Since small BaO.6Al2O3 crystallites prepared through a coprecipitation route had a similar sintering resistance, it was concluded that formation of barium hexaaluminate is a promising option for stabilizing combustion catalyst supports (Schwarz 1995). An alternate method to achieve the thermal stabilization of alumina without foreign additives was also reported. Since the transition of metastable phases to α-Al2O3 occurs predominantly at the contact between primary particles, the key for suppressing the rate of sintering without additives is preparing active aluminas in a morphological state in which the area of contact between primary particles is minimized. Alumina prepared by fume pyrolysis of sols consists of fibrillar boehmite, approximately 100 nm in length and 10 nm in diameter. After calcination at 1473 K for 30 h, the material maintained a surface area of 50 m2 g-l and still consisted of fibrils. This was ascribed to the suppression of the phase transformation to α-Al2O3. In the case of Mg(OH)2 as the starting reagent, washing with alcohol of the hydroxide precipitate leads to a drastic decrease in surface area of the calcined MgO. The effect was ascribed to formation of surface alkoxides and induction of particle-particle bridges through surface condensation reactions. This process favors the development of order in the precipitate. The bridges formed during washing were maintained through the calcination step. Also, the morphology of Mg(OH)2 precipitates was found to be dependent on whether the pH during precipitation and aging was above or below the isoelectric point (pH = 12). This demonstrates the influence of the electric charge of primary particles on their tendency toward aggregation (Schwarz 1995). b. Coprecipitation In the synthesis of multicomponent systems, the problems are even more complex. Coprecipitation rarely allows one to obtain good macroscopic homogeneity. In a system with two or more metallic compounds, the composition of the precipitate depends on the



50



differences in solubility between the components and the chemistry occurring during precipitation. Generally, under the conditions of either a slow precipitation rate or poor mixing within the reaction medium, coprecipitation is selective and the coprecipitate is heterogeneous in composition. Subsequent to formation of the coprecipitate, hydrothermal treatments which transform amorphous precipitates to crystalline materials with improved thermal stability and surface acidity may be carried This procedure is widely applied to prepare molecular sieves. Depending on the composition of the precipitate formed, two chemical routes should be distinguished in the coprecipitation procedures. The simplest case is that of sequential precipitation of separate chemical compounds. This occurs whenever there is a large difference in the solubility products of the compounds involved. The so-called “coprecipitates” of hydroxides, hydroxo carbonates, oxalates, and formats containing two or more different metals are generally non-homogeneous in composition and only very seldom generate a homogeneous mixed oxide by solid phase reactions at high calcination temperature. Doping or substitution of ions in these precipitates is difficult because of the different reactivities involved. The second possibility is the formation by coprecipitation of a well-defined chemical compound which might serve as a chemical precursor from which the final catalyst is obtained. The intermediate compound must be easily decomposed under mild calcination. This route is preferred whenever a better intimate mixing of the catalyst components is desired. The metal ratio in the precursor compound is, however, restricted to a quite rigid stoichiometry. Crystalline stoichiometric precipitates formed by several metal oxyanions (vanadates, chromates, tungstates, and molybdates) and a second metal cation may be further used to obtain an intimate interdispersion of the two metals. As an example, the activity of Cu/Cr catalysts depends on the amount of copper chromate, CuCrO4, formed during their preparation, and this is the precursor of the most active sites of the final catalyst (Schwarz 1995).



51



Other intermediates extensively studied as catalyst precursors comprise the class of mixed-metal hydrated hydroxo carbonates with a layered structure. Thus, during preparation of active copper catalysts used for synthesis of hydrocarbons or methanol by hydrogenation of CO the copper phase must be obtained highly interdispersed with at least one other oxide component. This structure stabilizes the very small CuO particles and favors further interaction of copper with the host oxide. A high degree of homogeneity at the atomic level for this class of catalysts may be achieved by decomposition of single phase precursors, such as either the hydroxo carbonates with the aurichalcite structure, (Cu,Zn)5(C02)2-(OH)6, from which binary Cu,Zn catalysts are prepared or with the lamellar hydrotalcite-type crystalline for preparation of highly active ternary catalysts, Cu Zn/(Al,Cr,Ga,Sc) (Schwarz 1995). The details of precipitation of these single phase precursors involve a careful control of pH and the rate of precipitation; the morphology of the precursor may influence the degree of interdispersion of the final multiphase catalyst. In these systems, because all elements are homogeneously distributed in the hydrotalcite phase, no surface segregation is observed and pseudomorphic thermal decomposition leads to a spinel-type oxide. The limits between which the ratio of metals in the catalyst may be varied depends on the stoichiometry and structure of the single phase precursor: for the Cu/Zn binary aurichalcite, it may be changed between quite large limits (0.02 to 0.301, while the structure of the ternary hydrotalcite allows the Cd Zn/Me ratio to be varied within much narrower limits; a typical value for single phase precursors of copper-based catalysts is 30/45/25. The hydrotalcite like coprecipitated precursors were recently used as intermediates for the preparation of other nonstoichiometric spinel-type catalysts, with the general formula M1+yCr2-2y/3O4 (M = Zn, Cu, Co); they are employed as catalysts for specific hydrogenation reactions (Schwarz 1995).



52



With a proper selection of metals and complexing agents, precipitation of mixedmetal polynuclear coordination compounds is possible. The use of coordination compounds as raw materials is a nonconventional procedure to prepare mixed oxides by a mild thermal decomposition. Recent literature in inorganic chemistry often makes reference to synthesis and characterization of several types of binuclear coordination compounds with molecularly organized structures that contain metals of interest for preparation of catalysts. For example, mixed metal complexes in the general series {NBu4[MCr-(ox)3]}x (where NBu4+ = tetrabutylammonium ion, ox2- = oxalate ion, and M = Mn2+, Fe2+, Co2+, Ni2+, form a three dimensional structure comprised of alternate arrays of Cr(III) and M(II) metals. Also in the series of µ-oxo-trinuclear mixed metal carboxylate complexes. [M2IIIMIIO(ac)6L3]. nL, where MIII = Fe, Co, Cr, M II = Fe, Co, Ni, Zn, Mn, Mg, and L= py, H2O, the molecular structure is composed of trinuclear, oxo-centered M 2IIIMIIO units (Schwarz 1995). It is known that thermal decomposition of polynuclear coordination compounds of the latter type yields mixed oxides with spinel structure. This suggests the use of other coordination compounds such as those mentioned above as potential precursors for the binary mixed oxides in the system CuO-ZnO-Cr 2O3. For the moment, preparation of ternary mixed-metal compounds remains a more difficult task. Polynuclear mixed metal complexes deserve more attention as precursors for the preparation of catalysts. This methodology has the advantage that the component metal ions are intimately bound in the molecular structure of the polynuclear compound and a homogeneous mixed-oxide phase or a composite oxide is more easily formed after either a mild decomposition or a hydrothermal treatment at moderate temperatures (Schwarz 1995). Finally, a new approach to the precipitation method is the use of organic solvents as precipitation media. The colloid chemistry is not easily extrapolated from the aqueous



53



phase to organic systems. In addition, organic solvents pose practical problems to catalyst manufacturing, but these difficulties can be offset by the special properties of catalysts precipitated from organic so1vents (Schwarz 1995). It is conceivable that the catalyst obtained in organic media has more accessible active sites than the catalyst obtained from the aqueous route. The difference in the texture corresponds to a high-performance catalyst which has found commercial recognition. In this example, the precursor acts as an improved matrix for the crystalline growth of the oxide active phase during the topotactic transformation. The properties that the solid will develop as a final catalyst are strongly affected by all structural and morphological changes which occur during the topotactic transformation (Schwarz 1995). E. Catalyst Deactivation Physical changes in a catalyst can lead to decay in performance. The five main causes of deactivation are poisoning of the active sites, fouling by coke deposits, thermal degradation, mechanical damage and corrosion/leaching by the reaction mixture. Poisoning occurs by adsorption of impurities in the feed, whilst fouling involves the covering of a surface with a deposit such as coke. If an impurity is not too strongly adsorbed on the catalyst and no reconstruction of the active site has occurred, regeneration of the catalyst may be possible. Many catalytic processes form carbonaceous deposits or ‘coke’ on the catalysts and this is the most common type of poisoning caused by reactants or products. Coke is produced by unwanted polymerisation and dehydrogenation (condensation) of organic molecules present in the feed or formed as a product. The reactions leave a layer of highly hydrogen deficient carbonaceous material on the catalyst surface, making the active sites inaccessible. Holdeman and Botty (1959) carried out electron microscopy studies to characterise the carbon deposits of silica-alumina catalysts. The results indicated that



54



the coke deposited was a finely divided, highly dispersed phase present within the ultimate pore structure of the catalyst. Holmes et al., (1997) carried out sorption studies on a sample of ZSM-5 to locate coke within the zeolitic pores and to differentiate between poisoning and blockage of the active sites. The coke formation was found to involve two major steps. The initial cracking reaction generated alkenes, which then underwent secondary reactions (cyclisation, dehydrogenation) to form substituted benzenes and naphthalenes. These smaller aromatics then underwent further cyclisation and dehydrogenation to form larger insoluble aromatic compounds. The coke was found to be located on both the external surface and within the zeolite pores. Hopkins et al., (1996) investigated the acidity and cracking activity during coke deactivation of ultrastable Y zeolite. Compared to a fresh USY zeolite, coke deactivated H-USY did not show significant changes in the acid strength distribution, number of acid sites, fraction of Brønsted and Lewis acid sites or pore size distribution. However, rapid loss in activity was observed and was said to be due to deposition of coke on active sites near the external crystal surface. Active sites in the inner portion of the zeolite particles were said to have remained unaffected by the coke. 2.3. Description Process of Previous Researches 2.3.1. Vacuum Pyrolysis of Waste Tires with Basic Additives Xinghua Zhang et. al. conducted an experiment of pyrolyzing Chinese car tires rubber with NaOH and Na2CO3 additives in a vacuum condition. The experiment was run at different temperature in order to selectively obtained valuable chemicals such as dl-limonene.



55



Figure 2. 8. Schematic Diagram of Experimental Apparatus (1) Pyrolysis Reactor (2) Electrical Furnace (3) Primary Condenser



(4) Liquid Collector (5) Secondary Condenser (6) Safe-buffer



(7) Vacuum Relay (8) Electromagnetic Valve (9) Vacuum Pump



Tire granules were sieved to a size range of 20-60 mesh and manually mixed with the powder anhydrous Na2CO3 and NaOH. The pyrolysis was performed in a stainless steel pyrolysis reactor equipped with several stainless steel plates to strengthen heat transfer. In the entire process the pyrolysis pressure was maintained at 3.5-4.0 kPa with temperature range from 450-600oC. With the increasing pyrolysis temperature, the yield of oil increased and the residue decreased correspondingly. NaOH presence in the process resulted in the highest value of oil yield at the same temperature reaction, 49.7 wt% at 480oC. 2.3.2. Pyrolysis of Latex Gloves in the Presence of Y-Zeolite In 2009, William J. Hall et. al. pyrolyzed two different brands of commercial rubber gloves in a fixed bed reactor (FBR). They occupied Y-zeolite catalyst in the process that was in the form of pellet and was activated at 550 oC for 2 hours. Y zeolite catalyst used in this study was composed of SiO2/Al2O3 ratio of 80.



Figure 2. 9. Fixed Bed Reactor Schematic



56



Two rubber gloves were mixed together and pyrolized in a fixed bed reactor. The pyrolysis temperature was either 380oC or 480oC. In the absence of catalyst, the pyrolyis oil consisted of dimmers, trimers, tetramers, pentamers, and hexamers, with limonene (dimer) being the most abundant compound. The Y-zeolite catalysed the formation of aromatic compounds such as toluene, xylene, ethyltoluenes, and naphthalenes, including naphthalene itself. It is also eliminated limonene and the polyisoprene oligomers that were present in the noncatalytic oil. 2.3.3. Thermal Conversion of Scrap Tyres Bajus and Olahova investigate the pyrolysis of both car and truck tires in a vacuum condition to find out the experimental conditions that can maximized liquid yields. Initially, scrap tyres were decomposed thermally in a batch reactor in an inert atmosphere for around 100 minutes. The final temperature of thermal degradation is 450oC with heating rate 16.5oC/min to 350oC, 8 minutes temperature stabilization; heating rate 9oC/min up to 44oC, heating rate of 7.5oC/min up to 480oC. The gas samples were taken at temperature 400oC, 450oC, and one hour after reaching the temperature 450oC in the first experiment and on reaching the temperature 570oC in the second experiment. The results show that the production of aromates C7-C10 decreased with the increasing temperature. This behaviour of aromatic fraction is due to Diels-Alder reactions that promote the formation of aromatic compounds from olefins. Isoprene and Benzene with temperature and the yield of aromatic C7-C10 fraction decreases, which is due to thermal cracking and secondary reactions at high temperatures. Meanwhile, Limonene is very unstable at high temperatures and operating under these conditions its yield undergoes a reduction to 4.6 wt. % at 570oC from 9.0 wt % at 450oC. 2.3.4. Copyrolysis of Scrap Tires with Oily Wastes In addition to pyrolysis conversion technology, there is another approach to utilize carbonaceous waste, called co-pyrolysis. Onenc et. al. for instance, who co-



57



pyrolized scrap tires and oily waste from ships to liquid fuels or chemical feedstock in the presence and absence of catalysts. Their work was aimed to see the influence of catalyst use and reaction temperature. It is reported that there was no influence of temperature on the product distribution over 500oC in scrap tires pyrolysis. The catalyst showed similar activity but Red Mud catalyst left fewer residue than that compared to ReUS-Y faujisite catalyst. Nevertheless, both catalyst had great effect on the distribution of compounds in the pyrolysis oils of scrap tires-oily waste mixture, particularly in D-limonene amount.



Figure 2.10. Schematic Diagram of the Pyrolysis Installation 2.3.5. Liquefaction of Waste Tires by Pyrolysis for Oil and Chemicals – A Review In accordance to review of some researches conducted over the last three decades, oil yields fluctuated with both temperatures and heating rates with no discernible trend (Quek and Balasubramanian 2013). It is also stated that low pyrolysis temperature and pressure as well as short vapour residence time increased the limonene yield (Pakdel, Pantea and Roy 2001). As when catalysts, such as HZSM5, HY and HBeta zeolites were occupied in reaction, gas yield and light aromatic hydrocarbon increase at the expense of the decreasing limonene yield (Quek and Balasubramanian 2013). 2.4. Reaction Mechanism



58



Natural rubber conversion to limonene goes under a chain reaction, as illustrated below: A



B



A+B



C



A+C



D



Therefore, to get to limonene compound, natural rubber has to take several stages. The mechanism of natural rubber monomer dimerization to limonene is as stated as:



Due to the given heat from thermal degradation process, polymer of isoprene breaks forming radical ion.



Empty s orbital ion H+ later forms temporary bonds with two end C atom. This phenomenon is known as Markownikoff’s rule.



With the presence of two positively charged H atom, the reactive radical forms a reactive 2-methyl-1-butene compound.



59



Atom C in radical ion attacks positively charged atom C in reactive 2-methyl-1butene, to form limonene.



By releasing one H+ atom, electron from CH3 bond with C+H2 resulting in 1methyl-4-(1-methylethenyl)-cyclohexene compound, also known as limonene.



CHAPTER III RESEARCH CONCEPT DESIGN



Limonene production from natural rubber is carried on two steps processes, which are catalyst preparation and catalytic reaction.



60



3.1. Materials 3.1.1. Natural Rubber Bulk natural rubber is supplied by PT. Sri Trang Lingga Indonesia of Palembang branch. Table 3.1 provides its composition analysis that is based on Indonesia National Standard (SNI). Table 3.1. Natural Rubber Composition



1. 2. 3. 4. 5. 6.



Parameter Dirt (%) Ash (%) Volatile Matter N2 Po PRI



Analysis Result 0.074 0.450 0.200 0.320 36 72 (SNI 06-1903-2000)



The pyrolysis reaction performed for limonene production uses fixed natural rubber mass of 80 gram for each run. 3.1.2. Catalyst There is barely any literature review available for using catalyst in the formation of limonene from rubber based material. Commercial catalysts used in those researches apt to produce oil with lower limonene content. In order to have a catalyst that may help to increase limonene content in the reaction, it is decided to leave commercial catalyst use and turn to self-produce it. The catalyst used for natural rubber conversion is initially prepared through precipitation method from CaO (calcium oxide) compound as main catalyst and SiO 2 (silica dioxide) as support catalyst. Powdered CaO supplied by PT Maju Agung Lestari has 90% purity, while SiO 2 supplied by PT. Sinergi Bersama Sukses has 99% purity. Due to SiO2 insolubility with various solvent other than hot base solution, Natrium hydroxide (NaOH) is used to dissolve it. Meanwhile, Hydrochloric acid



61



(HCl) is used to dissolve CaO and activate the catalyst. The CaO/SiO 2 catalyst is then used in reactor with varied bed volume of 80, 100, 120 gram. 3.2. Catalyst Preparation Precipitation method is used to prepare catalyst from CaO as main catalyst source and SiO2 as support catalyst that is to be used in catalytic pyrolysis reaction of natural rubber conversion. Figure 3.1 depicts the preparation stages to derive activated CaO/SiO 2 catalyst.



S A W D C A itg a r a c O CaO ih y li v in HCl at room rn Dissolved temperature i c a rg a ien id g n C n F a g tta e i in n y g g t



Dissolved in hot NaOH at 100oC



s t



i t g n d



At 100oC for 1 hour



At 30-35oC for 24 hours



i



t l



l



r s



At 110oC for 12 hours



At 500oC for 4 hours



Figure 3.1. Catalyst Preparation Steps The catalyst preparation step is initiated by having 98 gram silica dioxide (SiO 2) dissolved in 860 mL base solution of natrium hydroxide (NaOH) at 100 oC. Then, liquid silicate is mixed and stirred with 72 gram calcium oxide (CaO) which is dissolved in 51 mL hydrochloric acid (HCl) at room temperature prior to mixing. The mixing of both



62



main catalyst calcium oxide (CaO) dissolved in hydrocholoric acid (HCl) and silica dioxide (SiO2) support catalyst is intended to generate catalyst complex with hydrocholoric acid (HCl) as the activator. The precursor catalyst complex is stirred at temperature 100oC for 1 hour. It is then left for 24 hours at room temperature for aging. The resulting precipitate from aging stage is washed with deionized water then simultaneously filtered. After filtering, it was then dried at 110 oC for 12 hours. The drying is intended to remove the physisorbed water and not the chemisorbed water (Carlsson, et al. 2012). Finally, the CaO/SiO 2 catalyst is calcined at 500oC for 4 hours to have an activated catalyst. Calcination is also aimed to increase the catalyst support strength which goes along with the increasing calcination temperature (Carlsson, et al. 2012). After the activated catalyst is prepared, it is then used to evaluate its performance in the production of limonene from natural rubber. In a vacuum pyrolysis process, the catalyst is placed in the fix bed reactor to be in contact with reactant. In addition, the CaO/SiO2 catalyst characterization is performed by using SEM (Scanning Electron Microscopy) method.



3.3. Experimental Process Description



63



Figure 3.2. Catalytic Vacuum Pyrolysis Reaction of Natural Rubber Conversion Apparatus



64



Figure 3.3. Catalytic Pyrolysis Reaction of Natural Rubber Conversion Apparatus Degradation of polyisoprene along with the formation of pyrolytic oil goes under a catalytic reaction as described in Figure 3.2. As feed material, 80 gram of natural rubber is fed to the raw material tank (2) to be heated at varied temperature from 325, 350, 375 and 400oC. Prior to heating, vacuum pump (1) is used to evacuate air from raw material tank (2) to make sure that no air or oxygen exists during the heating process. Meanwhile, pressure indicator control is occupied to monitor gas pressure resulted from natural rubber cracking in the raw material tank. The resulting gas is channeled through gas valve to gas storage tank (3) in order to maintain low pressure condition. There is also a pressure indicator control installed at gas storage tank (3) to record the pressure of gas reactant. Gas reactant from gas storage tank (3) will then flowed to the fixed bed reactor (4) with existing CaO/SiO 2 catalyst inside. Catalyst mass used in pyrolysis reaction is varied 80, 100, and 120 gram. Both gas reactant and powdered catalyst are contacted in fixed bed reactor (4) at temperature that is set to be the same as temperature at raw material tank (2). Gas product out from reactor (4) is temporarily expanded in flash tank (5) before entering condenser (6). Pressure at fixed bed reactor (4) as well as pressure at flash tank (5) is also monitored. The gas product that flows out from flash tank (5) and enters condenser (6) is cooled down by the cooling water provided from water tank (7). A centrifugal pump (8) is used to circulate water from water tank (7) into and out from condenser (6) to cool gas product inside condenser tube. Thus, liquid sample as the result of condensed gas product was collected. This sample is then to be analyzed further by Gas Chromatography/Mass



65



Spectrometry (GC/MS) to observe quantitatively the oil content in it, limonene in particular.



CHAPTER IV RESULTS AND DISCUSSION



4.1. Catalyst Characterization CaO/SiO2 catalyst that is used in this work was analyzed through SEM (Scanning Electron Microscopy) method.



Figure 4.1. SEM analysis of CaO/SiO2 catalyst



66



SEM analysis of CaO/SiO2 catalyst with 22500 times magnifying as depicted in Figure 4.1. showed its irregular shape and pore size. From four spots that were measured, the catalyst pore size was ranged between 98-647 nm. The catalyst used in this experiment is vulnerable to coking, since it is used in reaction with polymer reactant. Polyisoprene as the main component of natural rubber forms other compounds beside limonene from its monomers. Too many chemical compounds formed may cause the desired product is blocked from entering catalyst active sites resulting in an ineffective catalyst activity. 4.2. Pyrolytic Oil Characterization Natural rubber conversion to limonene through vacuum pyrolysis produced both solid residue and pyrolytic oil. The detailed product distribution is as listed in Table 4.1. Table 4.1. Product Distribution of Natural Rubber from Varied Pyrolysis Condition



No.



Catalyst Mass (gr)



1.



Reaction Temperature (oC) 325



2.



350 80



3.



375



4.



400



5.



325



6.



350 100



7.



375



8.



400



9. 10.



120



325



Pressure (bar) 3.0 2.2 3.2 2.7 2.2 2.8 1.0 1.9 2.2



350



Pyrolytic Oil (ml) 5.2 5.8 8.0 9.4 7.6 15.0 15.5 17.0 9.5



Solid Residue (gr) 1.03 1.79 3.01 8.42 2.48 3.97 4.19 1.79 9.06



6.8 1.8



1.35



67



11.



375



12.



400



2.2 2.0



12.0 11.0



5.53 3.26



Overall assessment shows that temperature plays an important role in the increasing of pyrolytic oil. In majority, pyrolytic oil produced increases along with the increasing temperature. Although, some result doesn’t show that tendency due to other factors that may cause improper measurement. This is possible due to the leakage of reactant gas during the running process. Other pattern is to see the influence of pressure to the achieved pyrolytic oil. It can be seen that, for reaction run at the same temperature condition yet lower pressure, the resulting yield reached higher value than the one that run at higher reaction pressure. Furthermore, GC/MS analysis showed that the content of oil produced from the catalytic pyrolysis of natural rubber can be simplified for classification as follow: 1. Limonene, as the main purpose of the experimental project is to produce high content of limonene in oil yield. 2. Naphthalene along with its isomer and derivatives, as the prominent compounds found in the pyrolytic oil. 3. Other aromatic compounds, since the rest compounds formed in pyrolitic oil are classified as aromatic.



68



90 80 70 60 50 Percent Area (% ) 40 Limonene 30



Naphthalene



Other Aromatic Compounds



20 10 0 300



325



350



375



400



Temperature (oC)



Figure 4.2. shows the effect of pyrolytic temperature to the content of limonene, naphthalene and other aromatic compounds for 80 gram CaO/SiO 2 catalyst and 80 gram natural rubber used.



Figure 4.2. Effect of Temperature on Pyrolytic Oil Percent Area for Catalytic Pyrolysis Reaction with 80 gram Catalyst and 80 gram Natural Rubber



425



69



70 60 50 40 Percent Area (% ) 30 Limonene



Naphthalene



Other Aromatic Compounds



20 10 0 300



325



350



375



400



Temperature (oC)



The figure shows that limonene line gives insignificant increase at 375 oC and 400oC, though the amount initially decreased at 350oC. The highest value that it reached was 5.29% area for catalytic pyrolysis at 400oC. Meanwhile, the figure shows as if naphthalene and other aromatics other than limonene and naphthalene are influencing each other.



Figure 4.3. Effect of Temperature on Pyrolytic Oil Percent Area for Catalytic Pyrolysis Reaction with 100 gram Catalyst and 80 gram Natural Rubber



425



70



Nearly the same as the result shown in Figure 4.2., Figure 4.3 also shows that initially limonene percent area drop at 350 oC. It topped at 400oC for as much as 12.96% area. The interesting one is that, unlike Figure 4.2., Figure 4.3 shows that the changing of limonene is parallel to that of other aromatics compounds, and conversely to that of naphthalene. It seems that by having bigger catalyst ratio to natural rubber, both limonene and naphthalene content in pyrolytic oil is affected, conversely. In pyrolysis reaction using 100 gram catalyst and 80 gram natural rubber, limonene percent area content to the total compound found in the pyrolytic oil increases at 400 oC significantly in comparison with the one that used 80 gram catalyst and 80 gram natural rubber.



60 50 40



Percent Area (% ) Limonene



30 20



Naphthalene



Other Aromatic Compounds



10 0 300



325



350



375



Temperature (oC)



400



425



71



Figure 4.4. Effect of Temperature on Pyrolytic Oil Percent Area for Catalytic Pyrolysis Reaction with 120 gram Catalyst and 80 gram Natural Rubber Figure 4.4. rounds off the conclusion that limonene percent area is always dropped at 350oC from that of the amount at 325oC and continue to increase and reach the largest value at 400oC. Limonene percent area content for the pyrolysis reaction using catalyst CaO/SiO2 peaks at 14.89% for reaction using 120 gram catalyst and 80 gram natural rubber at 400oC. In contrast with limonene amount that increases along with the catalyst mass used, naphthalene content seems to decrease. Meanwhile, other aromatics compounds content seems to give different pattern. It tends to be independent from both limonene and naphthalene content in the pyrolitic oil, either judging from temperature factor or catalyst mass used in the experiment. Figure 4.5. to Figure 4.7. shows the effect of temperature and natural rubber to catalyst ratio on each group’s peak area. Limonene, naphthalene and other aromatics compounds percent area change is shown in Figure 4.5, Figure 4.6 and Figure 4.7, respectively. The ratio of natural rubber to catalyst ratio used in the experiment is growing smaller. Initially, the ratio is 1:1 for natural rubber and catalyst used. For the second variation, the amount of catalyst used is increased while natural rubber is fixed. This variation change the ratio of natural rubber to catalyst be 4:5. Meanwhile, the last variation is to have the smallest of all three variations. Catalyst mass is added to have natural rubber to catalyst weight ratio used in the experiment is 2:3.



72



20 18 16 14 12 Percent Area (% )



10 8 1:1



4:5



2:3



6 4 2 0 300



325



350



375



400



Temperature (oC)



Figure 4.5. Effect of Natural Rubber to Catalyst Ratio and Temperature on Limonene Peak Area in Pyrolytic Oil As it can be seen from Figure 4.5, limonene content reached its peak at 400oC for reaction that occupied smaller natural rubber to catalyst ratio. For each ratio, limonene content is found to drop at 350oC before it slowly rises at 375oC. Although the conclusion may not be fully agreed due to the significant different pattern showed by the result achieved from samples that run using 4:5 natural rubber to catalyst ratio.



425



73



Leakage may be the factor that gives the unsatisfying result drawn off by samples of catalytic pyrolysis using 4:5 ratio of natural rubber to catalyst. Despite that, it is concluded that temperature does influences the formation of limonene from natural rubber main component monomer’s, isoprene. 60 50 40 Percent Area (% )



30 1:1 20



4:5



2:3



10 0 300



325



350



375



400



425



Temperature (oC)



In contrast to limonene content that increases along with the decreasing ratio of natural rubber to catalyst, naphthalene content tend to drop at the maximum temperature attempted in this experiment.



74



Figure 4.6. Effect of Natural Rubber to Catalyst Ratio and Temperature on Naphthalene Peak Area in Pyrolytic Oil Figure 4.6 clearly showed that naphthalene content gives no rising for experiment that uses smallest natural rubber to catalyst ratio. Even though, it increases along with temperature at other natural rubber to catalyst ratio variations, naphthalene content drops at the highest temperature attempt for every ratio varied. It reached its peak at 375oC for samples that uses 1:1 ratio or 80 gram of natural rubber with 80 gram of catalyst. This maximum content of naphthalene reached 8.42% of total compound found in that sample read at minute 8.77 by GC/MS. As for aromatic compound other than naphthalene and limonene, Figure 4.7 depicts its percent area of total compound contained in the pyrolitic oil obtained. It is obvious that more aromatic compound is to be found from the samples that occupied higher temperature. This is due to the tendency of polymer to crack and form other compounds with lower carbon content when subjects to high temperature condition. 100 80 60 40 Percent Area (% ) 20 1:1 4:5 0



2:3



325375425 300350400 Temperature (oC)



75



Figure 4.7. Effect of Natural Rubber to Catalyst Ratio and Temperature on Other Aromatic Compounds Peak Area in Pyrolytic Oil As it can be concluded from Figure 4.7, other aromatics compounds content increase for each natural rubber to catalyst ratio variation at 400 oC. The first two variations cause aromatics content to decrease up to trial with 375oC of reaction temperature. However, a different result is given by samples that use 2:3 natural rubber to catalyst ratio. It steadily increases along with the increasing temperature. Natural rubber is very unstable after heated, it may then form many compounds which composed of shorter carbon chain. This fact explains the graphic trends which decreases and increases at certain temperature. Limonene was found to start composed at 300oC and mainly found at 370oC-450oC (Pakdel, Pantea and Roy 2001). It is consented to the result that shows at temperature 350oC as in Figure 4.2 through 4.4, limonene content decreases as other compound such as naphthalene increases. It means, that at that operating condition, though the formation of limonene has started, other aromatic compounds are also formed, and the previous limonene formed at 325 oC is degraded to lower aromatic compound due to its unstable characteristic (Pakdel, Pantea and Roy 2001). The trend that is shown at Figure 4.5 to Figure 4.7 is the decreasing content of naphthalene and the increasing content of limonene and other aromatic compounds along with the decreasing ratio of natural rubber to catalyst weight. The catalyst used in this process is intended to utilize a metal compound which provides higher free Gibbs energy in the formation of limonene. Based on the reaction mechanism of limonene formation from natural rubber, the process needs metal compound that is able to donate more



76



electrons. Thus, the active site of CaO/SiO2 catalyst used provides more metal compound to aid the dimerization of isoprene which increases along with the increasing catalyst weight used than natural rubber weight as the source of isoprene.



CHAPTER V CONCLUSION



Natural rubber conversion to limonene by vacuum pyrolysis using CaO/SiO 2 catalyst experiment is intended to find the optimum condition in order to obtain high limonene content with lower cost production. There are some factors to be considered to achieve that goal; among them are the use of catalyst and optimum operating condition. From the experiment conducted, it can be concluded that: 1. The variation of natural rubber to catalyst weight ratios influence the amount of limonene produced, as it is increased along with lower ratio implemented. For the same operating condition, samples that used lower ratio produce higher limonene content. As in 400oC, limonene content increases from 5.32% to 12.96% to 14.89% for the use of ratio 1, 0.8 and 0.6, respectively. 2. Increasing operating temperature generally increases the chance of limonene formation for the same natural rubber to catalyst ratio occupied. Limonene content increases from 10.96% to 14.89% for 0.6 natural rubber to catalyst ratio at 325 oC to 400oC.



77



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Woo, H. C., J. S. Lee, and K. H. Lee. "Catalytic Skeletal Isomerization of N-Butenes to Isobutene Over Natural Clinoptilolite Zeolite." Applied Catalysis A: General 134 (1996): 147-158. Wynnchuk, Maria. "Evaluation of Xylene Substitutes for A Paraffin Tissue Processing." Journal of Histotechnology, no. 2 (1994): 143-9. Xie, W., et al. "Initiation of Rubber Synthesis: In Vitro Comparisons of BenzophenoneModified Diphosphate Analogues in Three Rubber Preducing Species." Phytochemistry, 2008: 2539-2545. Zhang, Xinghua, Tiejun Wang, Longlong Ma, and Jie Chang. "Vacuum Pyrolysis of Waste Tires with Basic Additives." Waste Management 28, 2008: 2301-2310.



APPENDIX GCMS ANALYSIS OF PYROLITIC RESULTS



81



82



83



84



85



86



APPENDIX II ANALYSIS SAMPLE COMPOSITION SAMPLE 1 : 80 g, 3250C No



Retention Time



Tentative Assigment



Percent Area (%)



1 2



2.09 3.74



0.08 0.16



3 4 5 6 7 8 9 10



4.75 4.84 4.93 4.93 5.19 5.19 5.41 5.41



11 12 13 14



5.7 5.85 5.85 5.96



Hexane Toluene Cyclohexane, 1,3,5 - trimethyl-, alpha., 3.alpha.,5.beta. Ethylbenzene p- xylene o-xylene benzene, 1,3 - dimethyl p- xylene 2,4,6 - Octatriene, 2,6 - dimethylCyclopentane, 2- methyl - 1- methylene -3-(1methylenyl)1,3,6 - heptatriene , 2,5,6 - triemethyl D- Limone Cyclohexene, 4 - ethenyl -1,4 - dimethylBenzene , 1,3,5 - triemethyl-



0.06 0.19 2.32 2.32 0.61 0.61 0.12 0.12 0.19 0.62 0.62 0.97



87



15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36



6.08 6.21 6.26 6.26 6.26 6.47 6.47 6.49 6.54 6.71 6.79 6.79 6.79 7.04 7.04 7.04 7.07 7.07 7.07 7.11 7.11 7.11



37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60



7.34 7.34 7.34 7.41 7.41 7.41 7.61 7.61 7.66 7.66 7.66 7.8 7.84 7.88 7.93 7.93 8.14 8.43 8.43 8.43 8.89 8.89 9.28 9.28



Benzene, 1- ethyl - 3 - methyl Benzene, 1,3,5 - triemethyl Benzene, 1-ethenyl - 3 - methyl Benzene, cyclopropyl Benzene, 2- propenyl Cyclohexene, 1- mrthyl - 4 - (1-methyletyl)-, Benzene, 2- ethyl - 1, 3 - dimethylBenzene, 1,2 - diethyl Limonene Indene Benzene, 2-ethyl - 1,4 - dimethyl Benzene, 1 - ethyl - 3, 5 - dimethyl Benzene, 1- ethyl- 2, 4 - dimethyl Benzene, 1 - methyl - 2 - (1 - methylethyl)Benzene, 2 - ethyl - 1, 4 - diethyl Benzene, 1 - ethyl -2, 3 - dimethyl Benzene, 1 - methyl - 4 - (1 - methylethenyl) o – Isopropenyltoluene Benzene, (2 - methyl - 1 - propenyl) Benzene, 1- thenyl - 3, 5 - dimethyl benzene, 4 - ethenyl -1 , 2 - dimethyl Bicyclo (4.2.0) 0cta -1, 3, 5 triene, 2, 4 dimethyl Benzene, 1,2,4,5 - tetramethyl Benzene, 1,2,3,5 - tetramethyl Benzene, 1,2,3,5 - tetramethyl Benzene, (1 - methyl - 1 - propenyl ) - (E) Benzene, 4 - ethenyl -1, 2 - dimethyl Benzene , 2 - ethenyl - 1,3 - dimethyl 1,4 - Dihydronapthalene Benzene , 1 - methyl - 1, 2 - propadienyl 2 – Methylindene Benzene, 1- butynyl 1H Indene, 1 - methyl Benzene, 2 - ethenyl - 1, 3, 5 - triemethyl 1H - Indene, 1,1 - dimethyl 1H - Indene, 1,3 - dimethyl Napthalene Azulene 1 - o Tolylprop - 2 - en - 1 - one 1H -Indene , 1,3 - dimethyl ( 1 - Methylenebut -2 - enyl ) benzene (1 - Methylbuta - 1, 3, - dienyl) benzene Napthalene, 1 - methyl Napthalene, 2 - methyl 1,2,3 - Trimethylindene 1H - Indene , 1,1,3, - trimethyl -



0.34 3.04 0.5 0.5 0.5 0.48 0.48 2.08 4.17 0.49 1.38 1.38 1.38 0.53 0.53 0.54 0.87 0.87 0.87 0.53 0.53 0.53 1.37 1.37 1.37 0.47 0.47 0.47 1.47 1.47 1.49 1.49 1.49 0.38 0.34 0.41 6.08 6.08 0.51 0.59 0.59 0.59 2.06 2.06 0.64 0.64



88



61 62 63 64 65 66 67 68 69 70 71 72 73 74



9.33 9.33 9.52 9.52 9.52 9.62 9.62 9.65 9.65 9.65 9.76 9.76 9.78 9.85



75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106



10.02 10.02 10.16 10.16 10.43 10.43 10.43 10.46 10.46 10.46 10.54 10.54 10.7 11.48 11.87 11.87 11.93 11.93 11.93 12.03 12.23 12.23 12.23 12.47 12.47 12.47 12.51 12.51 12.55 12.64 12.64 12.64



Biphenyl Napthalene, 2 - ethenyl Napthalene, 1, 6 - dimethyl Napthalene, 1,5 - dimethyl Napthalene, 1, 7 - dimethyl Napthalene, 2,7 - dimethyl Napthalene, 1,6 - dimethyl Napthalene, 2,7 - dimethyl Napthalene, 2,6 - dimethyl Napthalene, 1,6 - dimethyl Napthalene, 2,6 - dimethyl Napthalene, 1,3 - dimethyl Napthalene, 2,6 - dimethyl 1H - Benzocycloheptene, 2,4a,5,6,7,8 hexahydro -3,5,5,9 -tetramethyl-, (R)1,1 ' - Biphenyl, 3 - methyl 1,1' - Biphenyl, 4 - methyl Napthalene, 1,4,5 - trimethyl Napthalene, 1- (1- methylethyl)Napthalene, 1,6,7 - trimethyl Napthalene, 1,4,6 - trimethyl Napthalene, 2,3,6 - trimethyl Napthalene, 1,6,7 - trimethyl Napthalene, 1,4,6 - trimethyl Napthalene, 2,3,6 - trimethyl Napthalene, 1,6,7 - trimethyl Azulene, 4,6,8 - trimethyl Fluorene 3H - Benz (e) indene, 2 - methyl Anthracene Penantrhere Anthracene Penantrhere 2 - Cyclopropen - 1 - one, 2,3 - diphenyl Phenanthrene, 9,10- dihydro - 1 - methyl Dibenzo (a,e) cyclooctane Anthracene, 9 - ethenyl Napthalene , 1- phenyl Anthracene, 1 - methyl Anthracene, 2 - methyl Penantrhene, 2- methyl Penantrhene, 2- methyl Anthracene, 1 - methyl Anthracene, 1 - methyl Penantrhene, 2- methyl Penantrhene, 1- methyl Penantrhene, 4- methyl -



1.47 1.47 1.44 1.44 1.44 1.17 1.17 1.09 1.09 1.09 0.33 0.33 0.48 0.74 0.65 0.65 0.28 0.28 0.24 0.24 0.24 0.17 0.17 0.17 0.19 0.19 0.3 0.21 1.1 1.1 0.39 0.39 0.39 0.21 0.36 0.36 0.36 0.28 0.28 0.28 0.63 0.63 0.31 0.35 0.35 0.35



89



107 108 109 110 111 112 113 114 115 116 117



12.83 13.2 13.2 13.2 13.35 13.35 13.62 13.64 13.64 14.42 15.73



118 119



15.73 15.73



Napthalene, 2 - Phenyl 9,10 - Dimethylanthracene Penanthrene, 2,5 - Dimethyl di-p-Tolylacetylene Fluoranthene Pyrene Pyrene Pyrene Fluorenthene Pyrene, 1- methyl 1,2 - Benzenedicarboylic acid, mono ( 2 ethylhexyl) ester 1,2 - Benzenedicarboylic acid, diissooctyl ester Di - n - octyl phthalate



0.41 0.14 0.14 0.14 0.25 0.25 0.32 0.22 0.22 0.13 0.98 0.98 0.98



SAMPLE 2 : 80 g, 3500C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23



Retention Time 3.74 4.92 4.92 5.19 5.19 5.19 5.84 5.84 5.89 5.89 5.96 5.96 6.08 6.21 6.21 6.21 6.26 6.26 6.49 6.49 6.53 6.71 6.79



Tentative Assigment Toluena p-Xylene o-Xylene Benzene, 1,3-dimethyl o-Xylene p-Xylene Limonene D-Limonene Benzene, 1-ethyl -2-methyl Benzene, 1-ethyl -3-methyl Benzene, 1,2,3-trimethyl Benzene, 1,3,5-trimethyl Benzene, 1,3,5-trimethyl Benzene, 1,2,3-trimethyl Benzene, 1,2,4-trimethyl Benzene, 1,3,5-trimethyl Benzene, 2-propenyl Benzene, 1-propenyl Benzene, 1,2-diethyl Benzene, 1,4-diethyl Limonene Benzene, 1-propynyl Benzene, 1-ethyl-3,5-dimethyl



Percent Area (%) 0.10 0.82 0.82 0.18 0.18 0.18 0.29 0.29 0.62 0.62 0.25 0.25 0.07 0.83 0.83 0.83 0.11 0.11 0.58 0.58 1.74 0.13 0.35



90



24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70



6.79 6.79 6.79 7.03 7.03 7.03 7.07 7.07 7.23 7.23 7.30 7.34 7.38 7.41 7.41 7.61 7.66 7.66 7.80 7.80 7.93 7.98 8.14 8.20 8.20 8.89 8.89 9.33 9.44 9.44 9.44 9.52 9.52 9.52 9.62 9.62 9.65 9.65 9.69 9.76 9.76 9.76 9.78 9.78 10.08 10.08 10.16



Benzene, 4-ethyl-1,2-dimethyl Benzene. 2-ethyl-1,4-dimethyl Benzene, 4-ethyl-1,2-dimethyl Benzene, 1-ethyl-3,5-dimethyl Benzene, 1-methyl-2-(1-methylethenyl) Benzene, 2-ethyl-1,4-dimethyl Benzene, 1-methyl-4-(1-methylethenyl) Benzene, (2-methyl-1,propenyl) Benzene, 1-methyl-2-(1-methylethenyl) Benzene, 1,2,4,5-tetramethyl Benzene, 1,2,3,4-tetramethyl Benzene, 1,2,4,5-tetramethyl Benzene, 2-ethenyl-1,4-dimethyl Benzene, 2-ethenyl-1,4-dimethyl Benzene, 2-ethenyl-1,3-dimethyl Benzene, 1-methyl-4-(1-methylethenyl) Benzene, 1-butynyl Benzene, (1-methyl-2-clclopropen-1-yl) Benzene (3-methyl-3-butenyl) Benzene, 2-ethenyl-1,3,5-trimethyl Naphthalene Naphthalene Naphthalene, 1,2,3,4-tetrahydro-5-methyl Benzene, (3-methyl-2-butenyl) Naphthalene, 1,2,3,4-tetrahydro-5-methyl Naphthalene, 2-methyl Naphthalene, 1-methyl Naphthalene, 2-ethenyl Naphthalene, 2,3-dimethyl Naphthalene, 2,7-dimethyl Naphthalene, 1-ethyl Naphthalene, 2,7-dimethyl Naphthalene, 2,6-dimethyl Naphthalene, 1,4-dimethyl Naphthalene, 1,6-dimethyl Naphthalene, 1,4-dimethyl Naphthalene, 2,6-dimethyl Naphthalene, 2,7-dimethyl Naphthalene, 2-ethenyl Naphthalene, 1,3-dimethyl Naphthalene, 1,4-dimethyl Naphthalene, 2,7-dimethyl Naphthalene, 2,6-dimethyl Naphthalene, 1,3-dimethyl Naphthalene, 2-(1-methylethenyl) Naphthalene, 1-(2-propenyl) Naphthalene, 1,4,6 - trimethyl



0.35 0.35 0.35 0.12 0.12 0.12 0.22 0.22 0.11 0.11 0.19 0.45 0.13 0.13 0.13 0.52 0.51 0.51 0.15 0.15 5.33 0.34 0.23 0.17 0.17 1.82 1.82 0.45 0.72 0.72 0.72 1.86 1.86 1.86 1.39 1.39 1.50 1.50 0.49 0.56 0.56 0.56 0.66 0.66 1.26 1.26 0.48



91



71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 10 0



10.16 10.16 10.29 10.29 10.28 10.44 10.44 10.46 11.93 12.23 12.47 12.47 12.55 12.55 12.64 12.83 13.33 13.61 13.93 14.17 14.22 14.22 14.36 14.36 14.36 14.41 16.53 16.53 18.58



Naphthalene, 2,3,6- trimethyl Naphthalene, 1,6,7 - trimethyl Benzene, [1-(2,4-cyclopentadien-1-ylidine) ethyl Naphthalene, 1,4,6 - trimethyl Naphthalene, 1,6,7 - trimethyl Naphthalene, 1,6,7 - trimethyl Naphthalene, 2,3,6- trimethyl Naphthalene, 1,6,7 - trimethyl Anthracene Naphthalene, 1-phenyl Anthracene, 2-methyl Anthracene, 1-methyl Anthracene, 2-methyl Anthracene, 1-methyl Anthracene, 2-methyl Naphthalene, 2-phenyl Pyrene Pyrene Pyrene, 1-methyl Pyrene, 2-methyl Pyrene, 1-methyl Pyrene, 2-methyl Pyrene, 4-methyl Pyrene, 2-methyl Pyrene, 1-methyl Pyrene, 1-methyl Benz [a] anthtracene, 1-methyl Benz [a] anthtracene, 7-methyl Benzo [e] pyrene



0.48 0.48 0.50 0.50 0.50 0.43 0.43 0.35 1.52 0.93 0.69 0.69 0.61 0.61 0.68 1.59 1.54 1.96 0.19 0.19 0.25 0.25 0.12 0.12 0.12 0.29 0.22 0.22 0.44



19.76



Benzo [e] pyrene



0.34



92



SAMPLE 3 : 80 g, 3750C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24



Retention Time 4.84 4.92 5.85 5.89 5.96 6.08 6.21 6.25 6.53 6.71 6.79 6.97 7.03 7.07 7.12 7.23 7.30 7.34 7.38 7.66 7.80 8.43 8.51 8.77



Tentative Assigment Ethylbenzene o-Xylene 1-ethenyl-1,4-dimethyl-Cyclohexene 1-ethyl-2-methyl-Benzene 1,3,5-trimethyl-Benzene 1-ethyl-3-methyl-Benzene 1,2,3-trimethyl-Benzene 1-ethenyl-3-methyl-Benzene D-Limonene Indene 1-ethyl-3,5-dimethyl-Benzene 1-ethyl-2,4-dimethyl-Benzene 2-ethyl-1,4-dimethyl-Benzene o-Isopropenyltoluene Bicyclo[4.2.0]octa-1,3,5-triene,4-dimethyl 4-ethyl-1,2-dimethyl-Benzene 1,2,4,5-tetramethyl-Benzene 1,2,3,5-tetramethyl-Benzene 1-methyl-4-(2-propenyl)-benzene 1-methyl-1H-indene 2-ethenyl-1,3,5-trimethyl-Benzene 1,3-dimethyl-1H-indene 2,3-dimethyl-1H-indene 1-methyl-Naphthalene



Percent Area (%) 0.10 1.92 0.39 1.71 0.90 0.18 2.72 0.42 2.59 0.80 1.18 0.39 0.40 0.60 0.31 0.21 0.29 1.17 0.22 1.37 0.14 0.42 0.65 8.42



93



25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71



8.89 9.29 9.33 9.44 9.52 9.63 9.65 9.76 9.78 10.02 10.16 10.30 10.33 10.44 10.46 10.54 10.64 10.70 10.73 10.90 11.38 11.48 11.87 11.93 12.00 12.03 12.23 12.46 12.51 12.55 12.64 12.83 13.01 13.06 13.09 13.16 13.34 13.61 13.93 14.08 14.17 14.22 14.36 14.41 14.74 15.54 15.63



1-methyl-Naphthalene 1,2,3-trimethyilidene Biphenyl 1-ethyl-Naphthalene 2,7-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 2,6-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 3-methyl-1,1'-biphenyl 2,3,6-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 1,4,6-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 3,3’-Dimethylbiphenyl Fluorene 3,4’-Dimethyl-1,1’-biphenyl 4,4’-Dimethylbiphenyl 1-methyl-9H-Fluorene 2-methyl-9H-Fluorene Anthracene Anthracene 2,3-dimethyl-9H-Fluorene 9,10-dihydro-1-methyl-phenantrene 1-phenyl-Naphthalene 2-methyl-Anthracene 2-methyl-phenanthrene 1-methyl-Anthracene 1-methyl- phenanthrene 2-phenyl-Naphthalene 9,10-dimethylanthracene 3,6-dimethyl- phenanthrene di-p-tolylacetylene 9,10-dimethylanthracene Flouranthene Pyrene 1-methyl-pyrene 11H-benzo[b]fluorene 1-methyl-pyrene 1-methyl-pyrene 4-methyl-pyrene 1-methyl-pyrene 1,3-dimethyl-pyrene Triphenylene Triphenylene



4.39 0.52 1.42 0.61 3.52 2.59 2.38 0.82 0.65 0.98 0.46 0.83 1.11 0.46 0.54 0.33 0.11 0.87 0.36 0.31 1.07 0.42 2.31 0.80 0.35 0.30 0.44 0.53 0.92 0.47 0.50 0.62 0.14 0.17 0.11 0.34 1.00 0.59 0.18 0.32 0.16 0.22 0.11 0.22 0.10 0.34 0.87



94



72 73



16.53 16.63



1-methyl-chrysene 1-methyl-benz[a] anthracene



0.28 0.22



SAMPLE 4 : 80 g, 4000C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24



Retention Time 4.92 5.18 5.84 5.89 5.96 6.07 6.21 6.26 6.54 6.71 6.79 6.98 7.03 7.07 7.34 7.51 7.61 7.66 7.80 8.77 8.89 9.28 9.33 9.52



Tentative Assigment p-Xylene 1,3-dimethyl-Benzene D-Limonene 1-ethyl-2-methyl-Benzene 1,2,3-trimethyl-Benzene 1-ethyl-3-methyl-Benzene 1,2,3-trimethyl-Benzene 1-ethenyl-3-methyl-Benzene Limonene Indene 1-ethyl-3,5-dimethyl-Benzene 1-ethyl-2,4-dimethyl-Benzene 1-methyl-4-(1-methylethyl)-Benzene 1-methyl-4-(1-methylethenyl)-Benzene 1,2,3,5-tetramethyl-Benzene 1-methyl-4-(2-propenyl)-benzene 1-butynyl-benzene 1-methylindene 2-ethenyl-1,3,5-trimethyl-Benzene 1-methyl-Naphthalene 1-methyl-Naphthalene 1,2,3-trimethyilidene Biphenyl 2,7-dimethyl-Naphthalene



Percent Area (%) 0.95 0.29 0.62 1.66 0.79 0.23 2.64 0.46 5.32 0.88 1.29 0.57 0.52 0.91 1.43 1.17 1.67 1.62 0.30 7.85 4.00 0.71 1.51 3.07



95



25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58



9.63 9.65 9.76 9.79 10.02 10.16 10.29 10.33 10.43 10.46 10.54 10.70 11.38 11.42 11.87 11.93 12.00 12.23 12.47 12.50 12.55 12.64 12.83 13.01 13.07 13.16 13.34 13.61 14.07 14.22 15.54 15.62 15.73 16.53



1,3-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 3-methyl-1,1'-biphenyl 1,4,6-trimethyl-Naphthalene 1,4,6-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene Fluorene 2-methyl-9H-Fluorene 1-methyl-9H-Fluorene Anthracene Phenantrene 2,3-dimethyl-9H-Fluorene 1-phenyl-Naphthalene 2-methyl-phenanthrene 2-methyl- Anthracene 1-methyl-Anthracene 1-methyl- phenanthrene 2-phenyl-Naphthalene 9,10-dimethylanthracene 3,6-dimethyl- phenanthrene 9,10-dimethylanthracene Flouranthene Pyrene 2-methyl- Flouranthene 1-methyl-pyrene Triphenylene Triphenylene 1,2-Benzenedicarboxylicacid,mono ester 7-methyl-benz[a] anthracene



2.19 2.12 0.76 0.51 1.06 0.40 0.73 0.95 0.37 0.44 0.26 0.78 0.79 0.38 2.10 0.67 0.14 0.33 0.59 0.91 0.47 0.50 0.63 0.15 0.19 0.36 0.65 0.99 0.36 0.25 0.41 1.01 1.14 0.28



96



SAMPLE 5 : 100 g, 3250C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25



Retention Time 5.85 5.85 6.55 4.92 4.92 5.19 5.19 5.19 5.89 5.89 5.96 5.96 6.08 6.08 6.08 6.21 6.21 6.21 6.26 6.26 6.26 6.50 6.50 6.50 6.72



Tentative Assigment Limonene D-Limonene Limonene o-Xylene p-Xylene o-Xylene Benzene,1,3-dimethylp-Xylene Benzene,1-ethyl-3-methylBenzene,1-ethyl-2-methylBenzene,1,2,3-trimethylBenzene,1,2,5-trimethylBenzene,1-ethyl-2-methylBenzene,1,2,4-trimethyl Benzene,1,2,3-trimethylBenzene,1,2,3-trimethylBenzene,1,2,4-trimethyl Benzene,1,3,5-trimethyl Benzene,1-ethenyl-4methyl Benzene,1-propenyl Benzene,cyclopropyl Benzene, 1,2-diethyl Benzene,1-ethyl-2,3-dimethylBenzene,4-ethyl-1,2-dimethylBenzene,1-ethynyl-4-methyl-



Percent Area (%) 1.75 1.75 11.97 2.14 2.14 0.62 0.62 0.62 3.23 3.23 1.45 1.45 0.47 0.47 0.47 4.42 4.42 4.42 0.95 0.95 0.95 4.07 4.07 4.07 1.40



97



26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72



6.72 6.79 6.79 6.79 6.98 6.98 6.98 7.00 7.00 7.04 7.04 7.04 7.07 7.07 7.23 7.23 7.23 7.30 7.34 7.34 7.52 7.61 7.61 7.66 7.66 7.93 7.98 8.76 8.76 9.33 9.45 9.45 9.45 9.52 9.52 9.62 9.62 9.65 9.65 10.29 10.29 10.33 10.33 11.87 11.93 12.23 12.47



Benzene,1-propynyl Benzene,4-ethyl-1,2-dimethylBenzene,1-ethyl-3,5-dimethylBenzene,1-ethyl-2,4-dimethylBenzene,1-ethyl-2,4-dimethylBenzene,1-methyl-3-(1-methylethyl)Benzene,1-methyl-2-(1-methylethyl)Benzene,1-methyl-4-(1-methylethenyl)Benzene,4-ethenyl-1,2-dimethylBenzene,4-ethyl-1,2-dimethylBenzene,2-ethyl-1,4-dimethylBenzene,1-methyl-2-(1-methylethyl)Benzene,1-methyl-4-(1-methylethenyl)Benzene,(2-methyl-1-propenyl)Benzene,1-methyl-4-(1-methylpropyl)Benzene,2-ethyl-1,4-dimethylBenzene,1,2,4,5-tetramethylBenzene,1,2,4,5-tetramethylBenzene,1,2,4,5-tetramethylBenzene,1,2,3,5-tetramethylBenzene,1-methyl-2-(2-propenyl)Benzene,1-methyl-1,2-propadienylBenzene,1-butynyl Benzene,1-methyl-4-(1-propynyl)Benzene,1-butynyl Naphthalene Naphthalene Naphthalene,1-methylNaphthalene,2-methylNaphthalene,2-ethenylNaphthalene,1-ethylNaphthalene,2-ethylNaphthalene,1,3-dimethylNaphthalene,2,6-dimethylNaphthalene,2,7-dimethylNaphthalene,1,6-dimethylNaphthalene,1,5-dimethylNaphthalene,2,7-dimethylNaphthalene,2,6-dimethylNaphthalene,2,3,6-trimethylNaphthalene,1,6,7-trimethylNaphthalene,1,6,7-trimethylNaphthalene,2,3,6-trimethylAnthracene Anthracene Naphthalene,1-phenylAnthracene



1.40 1.94 1.94 1.94 1.51 1.51 1.51 0.44 0.44 0.80 0.80 0.80 1.81 1.81 0.62 0.62 0.62 0.62 1.74 1.74 1.07 1.63 1.63 1.25 1.25 11.18 0.74 5.26 5.26 1.25 0.27 0.27 0.27 1.43 1.43 0.92 0.92 0.99 0.99 0.39 0.39 0.56 0.56 2.56 0.77 0.37 0.56



98



73 74 75 76 77 78 79 80 81



12.51 12.55 12.55 12.61 12.61 12.64 12.83 13.35 13.62



Anthracene,2-methylAnthracene,1-methylAnthracene,2-methylAnthracene,1-methylAnthracene,2-methylAnthracene,2-methylNaphthalene,2-phenylPyrene Pyrene



0.88 0.38 0.38 0.45 0.45 0.38 0.69 1.00 1.45



SAMPLE 6 : 100 g, 3500C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27



Retention Time 3.74 4.84 4.93 4.93 5.19 5.19 5.19 5.51 5.51 5.51 5.85 5.85 5.89 5.89 5.96 5.96 5.96 6.08 6.08 6.21 6.21 6.21 6.26 6.26 6.37 6.49 6.49



Tentative Assigment Toluene Ethylbenzene p-Xylene o-Xylene o-Xylene p-Xylene Benzene,1,3-dimethylBenzene,1-ethyl-2-methylBenzene,(1-methylethyl)Benzene,1-ethyl-3-methylD-Limonene Limonene Benzene,1-ethyl-2-methylBenzene,1-ethyl-3-methylBenzene,1,3,5-trimethylBenzene,1,2,3-trimethylBenzene,1,3,5-trimethylBenzene,1,3,5-trimethylBenzene,1,2,4-trimethylBenzene,1,2,3-trimethylBenzene,1,2,4-trimethylBenzene,1,3,5-trimethylBenzene, 2-propenylBenzene,1-ethenyl-4-methylBenzenemethanol,4-ethylBenzene,1,4-diethylBenzene,1,2,-diethyl-



Percent Area (%) 0.63 0.23 3.87 3.87 1.08 1.08 1.08 0.28 0.28 0.28 1.31 1.31 2.70 2.70 1.32 1.32 1.32 0.41 0.41 3.72 3.72 3.72 0.76 0.76 0.59 2.69 2.69



99



28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74



6.54 6.62 6.62 6.71 6.76 6.79 6.79 6.79 6.96 6.96 6.96 6.98 6.98 6.98 7.03 7.03 7.03 7.07 7.07 7.23 7.23 7.23 7.30 7.34 7.34 7.52 7.52 7.61 7.66 7.66 7.93 8.76 8.76 8.89 8.89 9.33 9.44 9.44 9.52 9.52 9.52 9.62 9.62 9.62 9.65 9.65 9.65



Limonene Benzene,cyclopropylBenzene, 1-propenylBenzene,1-propenylBenzene,1-methyl-4-propylBenzene,4-ethyl-1,2-dimethylBenzene,1-ethyl-4-dimethylBenzene,1-ethyl-3,5-dimethylBenzene,2-ethyl-1,4-dimethylBenzene,1-methyl-2-(1-methylethyl)Benzene,1-ethyl-3,5-dimethylBenzene,1-methyl-2-(1-methylethyl)Benzene,1-ethyl-2,4-dimethylBenzene,1-methyl-3-(1-methylethyl)Benzene,4-ethyl-1,2-dimethylBenzene,1-ethyl-2,3-dimethylBenzene,2-ethyl-1,4-dimethylBenzene,1-methyl-4-(1-methylethenyl)Benzene,(2-methyl-1-propenyl)Benzene,1-methyl-4-(1-methylpropyl)Benzene,1-methyl-2-(1-methylethyl)Benzene,2-ethyl-1,4-dimethylBenzene,1,2,4,5-tetramethyl-1,3,8-pBenzene,1,2,4,5-tetramethylBenzene,1,2,3,5-tetramethylBenzene,(1-methyl-1-propenyl)-,E Benzene,(1-methyl-1-propenyl)-,Z Benzene,1-butynylBenzene,1-butynylBenzene,1-methyl-4-(1-propynyl)-2Naphthalene Naphthalene,2-methyl Naphthalene,1-methyl Naphthalene,1-methyl Naphthalene,2-methyl Naphthalene,2-ethenyl Naphthalene,2,3-dimethyl1-NaphthalenepropionicacidNaphtalene Naphthalene,2,7-dimethylNaphthalene,1,5-dimethylNaphthalene,1,7-dimethylNaphthalene,1,5-dimethylNaphthalene,1,3-dimethylNaphthalene,1,4-dimethylNaphthalene,2,6-dimethylNaphthalene,2,7-dimethylNaphthalene,1,5-dimethyl-



8.26 0.62 0.62 1.04 0.32 1.45 1.45 1.45 0.53 0.53 0.53 0.65 0.65 0.65 0.64 0.64 0.64 1.13 1.13 0.55 0.55 0.55 0.55 1.45 1.45 1.10 1.10 1.59 1.36 1.36 8.65 7.41 7.41 3.66 3.66 1.62 0.70 0.70 2.76 2.76 2.76 1.85 1.85 1.85 1.90 1.90 1.90



100



75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102



9.76 9.76 9.76 10.09 10.30 10.30 10.33 10.33 10.33 10.44 10.44 10.57 10.57 10.57 11.87 11.93 12.23 12.23 12.47 12.51 12.55 12.61 12.64 12.84 13.20 13.35 13.62 15.73



Naphthalene,1,3-dimethylNaphthalene,1,4-dimethylNaphthalene,2,3-dimethylNaphthalene,2-(1-methylethenyl)Naphthalene,1,6,7-trimethylNaphthalene,2,3,6-trimethylNaphthalene,1,6,7-trimethylNaphthalene,1,4,6-trimethylNaphthalene,2,3,6-trimethylNaphthalene,1,4,6-trimethylNaphthalene,1,6,7-trimethylNaphthalene,1,6,7-trimethylNaphthalene,2,3,6-trimethylNaphthalene,1,4,5-trimethylAnthracene Anthracene Anthracene,9-ethenylNaphthalene,1-phenylAnthracene,2-methylAnthracene,2-methylAnthracene,2-methylAnthracene,2-methylAnthracene,1-methylNaphthalene,2-phenyl Anthracene,1,4-dimethylPyrene Pyrene 1,2-Benzenedicarboxylicacid,mono ester



0.66 0.66 0.66 0.89 0.63 0.63 0.78 0.78 0.78 0.31 0.31 0.34 0.34 0.34 2.02 0.85 0.29 0.29 0.54 0.84 0.44 0.53 0.57 0.44 0.46 0.51 0.62 0.83



101



SAMPLE 7 : 100 g, 3750C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28



Retention Time 3.74 4.92 5.18 5.84 5.89 5.96 6.07 6.21 6.54 6.71 6.79 6.98 7.00 7.03 7.07 7.34 7.41 7.61 7.66 7.80 7.90 7.92 8.43 8.46 8.51 8.76 8.89 9.20



Tentative Assigment Toluene o-Xylene 1,3-dimethyl-Benzene Limonene 1-ethyl-2-methyl-Benzene 1,2,3-trimethyl-Benzene 1,3,5-trimethyl-Benzene 1,2,3-trimethyl-Benzene Limonene Indene 1-ethyl-3,5-dimethyl-Benzene 1-ethyl-2,4-dimethyl-Benzene 1-methyl-4-(1-methylethenyl)-Benzene 1-ethyl-2,3-dimethyl-Benzene (2-methyl-1-propenyl)-benzene 1,2,4,5-tetramethyl-Benzene (1-methyl-1-propenyl)-benzene 1-butynyl-benzene 2-methylindene 2-ethenyl-1,3,5-trimethyl-Benzene 1,2,3,4-tetrahydro-1-methyl-naphthalene Naphthalene 1,3-dimethyl-1H-indene 1,3-dimethyl-1H-indene 2,3-dimethyl-1H-indene 2-methyl-Naphthalene 1-methyl-Naphthalene 1,2,3-trimethyilidene



Percent Area (%) 0.16 1.72 0.58 0.54 1.87 0.73 0.25 2.47 3.90 0.92 1.18 0.93 0.24 0.61 0.98 1.21 0.38 2.16 1.61 0.26 0.62 3.60 1.22 2.14 1.37 5.28 3.07 0.60



102



29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58



9.52 9.63 9.65 9.77 9.99 10.02 10.16 10.30 10.34 10.44 10.46 10.54 10.57 11.38 11.42 11.48 11.87 11.93 12.00 12.03 12.23 12.47 12.50 12.55 12.64 12.83 13.07 13.16 13.61 15.73



2,7-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 1,2-dihydro-3,5,8-trimethyl-Naphthalene 3-methyl-1,1'-biphenyl 2,3,6-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 1-methyl-9H-Fluorene 2-methyl-9H-Fluorene 2-methyl-9H-Fluorene Anthracene Anthracene 1-methyl-2-(2-phenylethenyl)-benzene 9,10-dihydro-1-methyl-phenantrene 1,4-dihydro-1,4-ethenoanthracene 2-methyl-phenanthrene 2-methyl-Anthracene 1-methyl-Anthracene 1-methyl-Anthracene 2-phenyl-Naphthalene 9,10-dimethylanthracene 9,10-dimethylanthracene pyrene mono (2-ethylhexyl) ester 1,2benzenedicarboxylic acid



3.61 2.33 2.55 0.96 0.33 0.87 0.82 0.97 1.81 0.67 0.63 0.61 0.66 0.62 0.36 0.29 1.66 0.69 0.28 0.18 0.12 0.45 0.66 0.36 0.43 0.31 0.13 0.26 0.59 0.29



103



SAMPLE 8 : 100 g, 4000C No 1 2 3 4 5 6 7



Retention Time 3.73 4.93 5.19 5.41 5.85 5.89 5.96



8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29



6.46 6.54 6.58 6.71 6.79 6.96 6.98 7.07 7.34 7.42 7.61 7.66 7.89 7.92 8.42 8.47 8.51 8.75 8.88 9.28 9.33 9.52



Tentative Assigment Toluene p-Xylene p-Xylene 1,2,6,6-tetramethyl-1,3-cyclohexadiene Limonene 1-ethyl-3-methyl-Benzene 1,2,3-trimethyl-Benzene 1-methyl-4-(1-methylethyl)-,(R)cyclohexene Limonene 5-ethylidene-1-methyl-cycloheptene Indene 4-ethyl-1,2-dimethyl-Benzene 1-methyl-2-(1-methylethyl)-benzene 1-methyl-2-(1-methylethyl)-benzene o-isopropenyltoluene 1,2,4,5-tetramethyl-Benzene 1-methyl-2-(2-propenyl)-benzene 1-butynyl-benzene 2-methylidene 2,3-dihydro-1,6-dimethyl-1H-Indene Naphthalene 1,3-dimethyl-1H-indene 1,3-dimethyl-1H-indene 2,3-dimethyl-1H-indene 2-methyl-Naphthalene 1-methyl-Naphthalene 1,2,3-trimethyilidene biphenyl 2,6-dimethyl-Naphthalene



Percent Area (%) 1.84 6.82 1.91 0.51 2.54 4.51 1.32 1.05 12.96 0.59 1.43 1.84 0.40 0.92 1.64 1.58 0.40 2.25 1.56 0.49 5.52 0.73 1.38 0.84 5.68 2.77 0.53 0.67 1.91



104



30 31 32 33 34 35 36 37 38 39 40



9.62 9.64 10.02 10.29 10.33 11.38 11.87 11.93 12.47 12.51 13.62



1,3-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 3-methyl-1,1'-biphenyl 1,6,7-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 2-methyl-9H-Fluorene Anthracene phenanthrene 1-methyl-phenanthrene 2-methyl-phenanthrene Pyrene



1.24 1.32 0.30 0.34 0.61 0.32 1.50 0.49 0.51 0.69 0.82



SAMPLE 9 : 120 g, 3250C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29



Retention Time 5.84 5.89 5.96 6.21 6.46 6.53 6.71 6.79 6.97 7.07 7.34 7.61 7.66 7.92 7.98 8.42 8.47 8.75 8.88 9.28 9.34 9.52 9.62 9.65 9.76 10.30 10.33 10.44 10.71



Tentative Assigment D-Limonene 1-ethyl-3-methyl-Benzene 1,3,5-trimethyl-Benzene 1,3,5-trimethyl-Benzene 1-methyl-4-(1-methylethyl)-,(R)-cyclohexene Limonene Indene 2-ethyl-1,4-dimethyl-Benzene 1-ethyl-2,4-dimethyl-Benzene 1-methyl-4-(1-methylethenyl)-Benzene 1,2,4,5-tetramethyl-Benzene 1-butynyl-benzene 1-methyl-1H-indene Azulene Naphthalene 1,3-dimethyl-1H-indene 1,1-dimethyl-1H-indene 1-methyl-Naphthalene 1-methyl-Naphthalene 1,2,3-trimethyilidene biphenyl 2,6-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene Fluorene



Percent Area (%) 0.85 2.25 1.28 4.39 0.54 10.96 1.03 2.05 1.20 1.45 2.31 2.86 2.61 7.01 1.02 0.76 1.83 1.47 6.59 0.76 0.93 5.05 3.47 4.60 1.47 0.79 1.87 0.64 0.68



105



30



11.89



Anthracene



0.35



SAMPLE 10 : 120 g, 3500C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30



Retention Time 4.92 5.19 5.85 5.89 5.96 6.10 6.21 6.25 6.46 6.54 6.71 6.79 6.98 7.00 7.07 7.34 7.51 7.66 7.80 7.92 8.42 8.47 8.51 8.54 8.76 8.89 9.28 9.33 9.52 9.62



Tentative Assigment p-Xylene o-Xylene D-Limonene 1-ethyl-2-methyl-Benzene 1,3,5-trimethyl-Benzene 2,6-dimethyl-2,4,6-octatriene 1,3,5-trimethyl-Benzene 1-ethenyl-4-methyl-Benzene 1-methyl-4-(1-methylethyl)-,(R)-cyclohexene Limonene Indene 1-ethyl-2,4-dimethyl-Benzene 2-ethyl-1,3-dimethyl-Benzene 1-methyl-4-(1-methylethenyl)-benzene (2-methyl-1-propenyl)-benzene 1,2,4,5-tetramethyl-Benzene 1-methyl-2-(2-propenyl)-benzene 2-methylidene 2-ethenyl-1,3,5-trimethyl-Benzene Naphthalene 4,7-dimethyl-1H-indene 1,3-dimethyl-1H-indene 4,7-dimethyl-1H-indene 2,3-dimethyl-1H-indene 1-methyl-Naphthalene 1-methyl-Naphthalene 1,2,3-trimethyilidene biphenyl 2,7-dimethyl-Naphthalene 1,5-dimethyl-Naphthalene



Percent Area (%) 1.53 0.45 1.16 2.04 0.87 1.00 2,92 0.50 0.67 9.54 0.98 1.57 1.06 0.26 1.13 1.62 1.06 1.57 0.26 8.21 0.94 1.80 1.22 0.64 7.92 4.15 1.03 1.38 3.59 2.43



106



31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54



9.65 9.76 9.78 10.02 10.16 10.29 10.33 10.43 10.45 10.54 10.70 11.37 11.41 11.87 11.93 12.47 12.50 12.55 12.61 12.63 12.83 13.16 13.35 13.61



2,7-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 1,4-dimethyl-Naphthalene 3-methyl-1,1'-biphenyl 1,4,6-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 1,4,6-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene Fluorene 2-methyl-9H-Fluorene 1-methyl-9H-Fluorene Anthracene Anthracene 2-methyl-Anthracene 2-methyl-Anthracene 1-methyl-Anthracene 1-methyl-phenanthrene 1-methyl-Anthracene 2-phenyl-Naphthalene 2,5-dimethyl-phenanthrene Flouranthene Pyrene



2.60 0.91 0.57 0.67 0.46 0.56 1.14 0.41 0.42 0.24 0.74 0.59 0.25 1.75 0.50 0.67 0.94 0.52 0.94 0.63 0.46 0.31 0.50 0.97



107



SAMPLE 11 : 120 g, 3750C No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30



Retention Time 3.74 4.83 4.93 5.19 5.41 5.85 5.89 5.96 6.22 6.25 6.55 6.71 6.79 6.98 7.00 7.03 7.07 7.30 7.34 7.51 7.61 7.66 8.42 8.47 8.51 8.76 8.89 9.28 9.33 9.52



Tentative Assigment Toluene Ethylbenzene p-Xylene p-Xylene 1,2,6,6-tetramethyl-1,3-cyclohexadiene D-Limonene 1-ethyl-3-methyl-Benzene 2-ethyl-1,4-dimethyl-Benzene 1,2,3-trimethyl-Benzene Cyclopropyl-benzene Limonene Indene 1-ethyl-2,4-dimethyl-Benzene 1-ethyl-2,4-dimethyl-Benzene 1-methyl-4-(1-methylethenyl)-Benzene 1-ethyl-2,4-dimethyl-Benzene o-Isopropenyltoluene 1,2,4,5-tetramethyl-Benzene 1,2,3,5-tetramethyl-Benzene 1-methyl-2-(2-propenyl)-benzene 1-butynyl-benzene 1-butynyl-benzene 1,3-dimethyl-1H-indene 1,3-dimethyl-1H-indene 4,7-dimethyl-1H-indene 1-methyl-Naphthalene 1-methyl-Naphthalene 1,2,3-trimethyilidene biphenyl 2,7-dimethyl-Naphthalene



Percent Area (%) 0.73 0.45 5.62 1.48 0.33 1.97 4.53 2.05 5.45 0.92 11.59 1.26 2.03 1.11 0.27 0.75 1.06 0.28 1.51 0.54 1.92 1.47 0.52 1.14 0.99 6.57 3.52 0.44 0.69 2.80



108



31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53



9.62 9.65 9.76 9.78 10.02 10.15 10.29 10.33 10.43 10.45 10.70 11.37 11.42 11.87 11.93 12.47 12.50 12.55 12.63 12.83 13.16 13.61 15.73



2,7-dimethyl-Naphthalene 2,6-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 1,4-dimethyl-Naphthalene 3-methyl-1,1'-biphenyl 2,3,6-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 1,4,6-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 2,3,6-trimethyl-Naphthalene Fluorene 1-methyl-9H-Fluorene 1-methyl-9H-Fluorene Anthracene 9-methylene-9H-Fluorene 2-methyl-phenanthrene 2-methyl-phenanthrene 1-methyl-Anthracene 1-methyl-phenanthrene 2-phenyl-Naphthalene 9,10-dimethylanthracene pyrene mono (2-ethylhexyl) ester 1,2benzenedicarboxylic acid



1.96 1.95 0.49 0.31 0.52 0.43 0.54 1.14 0.42 0.29 0.38 0.49 0.23 1.20 0.34 0.53 0.73 0.40 0.50 0.32 0.41 0.39 0.85



109



SAMPLE 12 : 120 g, 4000C No 1 2 3 4 5 6 7 8 9 10 11



Retention Time 3.73 4.83 4.92 5.19 5.41 5.85 5.89 5.96 6.10 6.21 6.25



12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29



6.47 6.54 6.58 6.62 6.71 6.79 6.98 7.03 7.07 7.30 7.34 7.61 7.66 7.80 7.92 8.42 8.46 8.51



Tentative Assigment Toluene Ethylbenzene o-Xylene 1,3-dimethyl-Benzene 1,2,6,6-tetramethyl-1,3-cyclohexadiene D-Limonene 1-ethyl-2-methyl-Benzene 1,3,5-trimethyl-Benzene 3,4-dimethyl-2,4,6-octatriene 1,2,3-trimethyl-Benzene 1-ethenyl-3-methyl-Benzene 1-methyl-4-(1-methylethyl)-,(R)cyclohexene Limonene 5-ethylidene-1-methyl-cycloheptene 5-ethylidene-1-methyl-cycloheptene Indene 1-ethyl-3,5-dimethyl-Benzene 1-methyl-2-(1-methylethyl)-benzene 2-ethyl-1,4-dimethyl-Benzene 1-methyl-4-(1-methylethenyl)-Benzene 1,2,4,5-tetramethyl-Benzene 1,2,3,5-tetramethyl-Benzene 1-butynyl-benzene 2-methylidene 2-ethenyl-1,3,5-trimethyl-Benzene Naphthalene 1,3-dimethyl-1H-indene 1,3-dimethyl-1H-indene 4,7-dimethyl-1H-indene



Percent Area (%) 0.85 0.35 4.24 1.16 0.33 2.32 3.81 1.29 2.04 5.07 0.99 1.04 14.89 0.57 1.01 1.63 2.35 1.91 0.88 1.52 0.71 1.89 2.42 1.76 0.23 5.17 0.59 1.18 1.05



110



30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51



8.76 8.89 9.28 9.33 9.52 9.62 9.65 9.76 9.87 10.02 10.16 10.30 10.33 10.43 10.46 10.70 11.37 11.87 12.47 12.51 12.61 13.62



2-methyl-Naphthalene 1-methyl-Naphthalene 1,2,3-trimethyilidene biphenyl 2,7-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 2,7-dimethyl-Naphthalene 1,3-dimethyl-Naphthalene 2,3-dimethyl-Naphthalene 3-methyl-1,1'-biphenyl 2,3,6-trimethyl-Naphthalene 1,6,7-trimethyl-Naphthalene 1,4,6-trimethyl-Naphthalene 1,4,5-trimethyl-Naphthalene 1,4,6-trimethyl-Naphthalene Fluorene 2-methyl-9H-Fluorene Anthracene 2-methyl-Anthracene 2-methyl-Anthracene 1-methyl-phenanthrene Pyrene



5.33 2.67 0.38 0.51 2.48 1.76 1.85 0.58 0.68 0.37 0.58 0.40 0.82 0.29 0.31 0.48 0.24 0.56 0.29 0.39 0.11 0.18



111



APPENDIX III EXPERIMENTAL APPARATUS



1. Raw Material



Natural Rubber



CaO dissolved in HCl



CaO, Silica



Silica dissolved in NaOH



Aging



112



Drying 2. Product



Pyrolitic oil



CaO/SiO2 Catalyst



113