Kinetika reaksi hidroksilasi epoksi minyak jarak pagar menggunakan katalis bentonit
Abstract
Hydroxylation kinetics of jatropha oil epoxy using bentonite catalyst.
Based on chemical properties such as fatty acid compositions and iodium value, jatropha curcas oil can potentially be applied as lubricant. Unsaturation of this oil decreases its oxidative stability. Improvement of this property may be done by chemical modification involving epoxidation and oxirane ring opening with bentonite catalyst, forming polyol by hydroxylation. The purpose of this research is to characterize the products and kinetics of the oxirane ring opening reaction. The results of chemical analysis by titration for residual oxiranes and hydroxyl formed in the reaction system, was showed using ir spectroscopy. Their effects were to reduce epoxy groups at 824-842 cm−1 and appearance of hydroxyl groups at the oh characteristic absorption peak from 3450-3800 cm−1. The oxirane number of epoxidized jatropha oil was reduced from 4.7% to 0.05% by ring opening. The kinetics of the oxirane ring opening of epoxidized jatropha curcas oil by methanol with bentonite was studied at 50, 60, and 65 oc. The oxirane ring opening analyzed by the pseudo-homogeneous approach followed a pseudo-first order kinetics. From the temperature dependence of the rate, reaction enthalpy (δh) and activation energy (δea) were found to be 8,27 kcal mol−1 and 7,63 kcal mol−1, respectively.
Keywords: epoxidized jatropha curcas, hydroxyl, oxirane, bentonite, kinetic
Abstrak
Berdasarkan sifat-sifat komposisi asam lemak dan bilangan iodium, minyak jarak pagar (Jatropha curcas) berpotensi menjadi bahan dasar pelumas. Meskipun demikian, kandungan ikatan tidak jenuh minyak ini menurunkan kestabilan oksidasinya. Kestabilan oksidasi ini dapat diperbaiki melalui modifikasi kimiawi dengan reaksi epoksidasi yang menghilangkan ikatan rangkap. Ini dilakukan melalui reaksi hidroksilasi dengan membuka ikatan gugus oksirana epoksi. Tujuan penelitian ini adalah mengkarakterisasi produk, serta mempelajari kinetika reaksi pembukaan cincin oksirana oleh metanol dengan katalis bentonit untuk membentuk poliol. Hasil analisis FTIR produk reaksi menunjukkan penurunan intensitas gugus epoksi pada bilangan gelombang 824-842 cm−1 dan munculnya gugus hidroksil pada bilangan gelombang 3450-3800 cm−1. Bilangan oksirana epoksi jarak pagar berkurang dari 4,7% menjadi 0,05% setelah pembukaan cincin. Bilangan hidroksil poliol adalah sebesar 165,77. Pengukuran kinetika pembukaan cincin pada gugus oksirana dari epoksi jarak pagar dilakukan pada 50, 60, dan 65oC. Analisis data laju reaksi yang dianalisis dengan pendekatan sistem pseudohomogen menunjukkan bahwa reaksi mengikut kinetika orde-1 semu. Dari perubahan laju reaksi terhadap temperatur diperoleh nilai entalpi reaksi dan energi aktivasi sebesar masing-masing 8,27 kkal mol-1 dan 7,63 kkal mol-1.
Kata kunci: epoksi jarak pagar, hidroksil, oksirana, bentonit, kinetika
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Bargaya, F. A.; Criz, M. I.; Gatineau, L.; Fripiat, J. J., Adsorption of alcohol by smectites: IV. Models, Clay Minerals, 1981, 16(1), 115-122.
Campanella, A.; Baltanás, M. A., Degradation of oxirane ring of epoxidized vegetable oils in liquid-liquid heterogeneous reaction systems, Chemical Engineering Journal, 2006, 118(3), 141-152.
Chauhan, B. S., Principles of Biochemistry and Biophysics; University Science Press: New Delhi, 2008; hlm. 146.
El-Diwani, G.; El Rafei, S.; Hawash, S.; Khalil, A. A., Recovery of phorbol from oil of an egyptian jatropha, Asian Journal of Plant Sciences, 2012, 11(3), 117-123.
Hwang, H. S.; Erhan, S. Z., Synthetic lubricant basestocks from epoxidized soybean oil and Guerbet alcohols, Industrial Crops and Products, 2006, 23(3), 311-317.
Hodar, F. J. M., Heterogeneous Catalysis, Lecture, Advanced Catalysis and Organometallic Chemistry Intensive Programs (IP) Lifelong Learning Program Erasmus, Camerino, Italy, 2009.
Kaurav, M. S., Engineering Chemistry with Laboratory Experiments; PHI Learning Private Limited: New Delhi, 2011; hlm. 209.
Kiatsimkul, P.; Suppes, G. J.; Hsieh, F.; Lozada, Z.; Tu Y. C., Preparation of high hydroxyl equivalent weight polyols from vegetable oils, Industrial Crops and Products, 2008, 27(3), 257-264.
Levenspiel, O., Chemical Reaction Engineering; John Wiley & Sons: New York, 2006.
Lathi, P. S.; Mattiasson, B., Green approach for the preparation of biodegradable lubricant base stock from epoxidized vegetable oil, Applied Catalysis B: Environmental, 2006, 69 (3-4), 207-212.
Lin, B.; Yang, L.; Dai, H.; Yi, A., Kinetic studies on oxirane cleavage of epoxidized soybean oil by methanol and characterization of polyols, Journal of the American Oil Chemists’ Society, 2008, 85(2), 113-117.
Liu, Y. H.; Liu, Q. S.; Zhang, Z. H., Amberlyst-15 as a new and reuseable catalyst for regioselective ring-opening reactions of epoxides to β-alkoxy alcohols, Journal of Molecular Catalysis A: Chemical, 2008, 296 (1), 42-46.
Olebunne, F. L.; Igbokwe, P. K.; Onyelucheya O. E.; Osoka, E. C.; Ekeke, I. C., Mechanistic modeling of clay-catalysed liquid-phase esterification of acetic acid, Journal of Emerging Trends in Engineering and Applied Sciences, 2011, 2(4), 631-635.
Megawati; Sediawan, W. B.; Sulistyo, H.; Hidayat, M., Pseudo-homogeneous kinetic of dilute-acid hydrolysis of rice husk for ethanol production: effect of sugar degradation, International Journal of Engineering and Applied Sciences, 2010, 6(1), 135-140.
Nugrahani, R. A., Perancangan Proses Pembuatan Pelumas Dasar Sintetis dari Minyak Jarak Pagar (Jatropha Curcas L.): Hasil Modifikasi, Disertasi Doktor, Institut Pertanian Bogor, 2008.
Nugrahani, R. A.; Firdaus, F. E.; Widyawati, Y.; Firginia, H.; Purnama, R., Kondisi Optimum Reaksi Hidroksilasi terhadap Epoksi Jarak Pagar (Jatropha curcas L.) Menggunakan Asam Asetat Glasial dengan Katalis Resin, Prosiding Seminar Nasional Teknik Kimia Indonesia dan Musyawarah Nasional APTEKINDO, Jakarta, 20-21 September 2012, 839-846.
Nugrahani, R. A.; Mangunwidjaja, D.; Suryani, A.; Machfud; Sudradjat, R., Optimasi proses dan kinetika reaksi epoksidasi minyak jarak pagar (Jatropha curcas L.) dengan hidrogen peroksida, Jurnal Teknologi Industri Pertanian, 2007, 18(2), 66-70.
Nzikou, J. M.; Matos, L.; Mbemba, F.; Ndangui, C. B.; Pambou-Tobi, N. P. G.; Kimbonguila, A.; Silou, Th.; Linder, M.; Desobry, S., Characteristics and composition of Jatropha curcas oils, variety congo-brazzaville, Research Journal of Applied Sciences, Engineering and Technology, 2009, 1(3), 154-159.
Okieimen, F. E.; Bakare, O. I.; Okieimen, C. O., Studies on the epoxidation of rubber seed oil, Industrial Crops and Products, 2002, 15(2), 139-144.
Petrovic, Z.; Guo, A.; Javni, I., Process for the Preparation of Vegetable Oil-Based Polyols and Electroinsulating Casting Compounds Created from Vegetable Oil-Based Polyols, U.S. Patent 6,573,354, 3 Juni 2003.
Purwanto, E., The Synthesis of Polyol from Rice Bran Oil (RBO) through Epoxidation and Hydroxylation Reactions, Tesis Magister, University of Adelaide, 2010.
Rustamaji, H.; Sulistyo, H.; Budiman, A.; Pemodelan dan simulasi kinetika reaksi alkoholisis minyak jarak pagar (Jatropha curcas) dengan katalisator zirkonia tersulfatasi, Jurnal Rekayasa Proses, 2010, 4(1), 19-24.
Zeng, Z., Cui, L.; Xue, W.; Chen, J.; Che, Y; Recent Developments on the Mechanism and Kinetics of Esterification Reaction Promoted by Various Catalysts; dalam Chemical Kinetics, Ed. Vitek Patel, 2012, http://www.intechopen. com/books/chemical-kinetics/recent-develop ments-on-the-mechanism-and-kinetics-of-est erification-reaction-promoted-by-various-cat (akses 2012).
DOI: http://dx.doi.org/10.5614/jtki.2013.12.2.5
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