KARAKTERISASI DAN AKTIVITAS KATALITIK BERBAGAI VARIASI KOMPOSISI KATALIS Ni DAN ZnBr2 DALAM ?-Al2O3 UNTUK ISOMERISASI DAN HIDROGENASI (R)-(+)-SITRONELAL

ED Iftitah, Muchalal -, W Trisunaryanti, R Armunanto

Abstract


Pengaruh sifat dan karakter berbagai variasi komposisi katalis Ni dan ZnBr2 yang terimpregnasi dalam ?-Al2O3 terhadap aktivitas dan selektivitasnya untuk reaksi isomerisasi dan hidrogenasi (R)-(+)-Sitronelal telah dilakukan. Dalam penelitian ini, terdapat tiga jenis variasi komposisi Ni dan ZnBr2 dalam ?-Al2O3, yaitu: A1=Ni/ZnBr2/?-Al2O3 (3:2), A2=Ni/ZnBr2/?-Al2O3 (1:1) dan A3=Ni/ZnBr2/?-Al2O3 (2:3). Katalis dikarakterisasi menggunakan X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, dan SEM-EELS. Luas area permukaan spesifik dan porositasnya ditentukan berdasarkan adsorption-desorption gas nitrogen pada 77 K. Distribusi dan volume pori ditentukan dengan desorption isotherm pada P/Po ? 0,3. Hasil yang didapat menunjukkan bahwa terdapat hubungan antara karakter dan sifat katalis dengan aktivitas katalitiknya terhadap produk isomerisasi dan hidrogenasi (R)-(+)-Sitronelal. Uji aktivitas dilakukan dalam sebuah reaktor mini dengan 0,5 g katalis dan 3 mL (R)-(+)-Sitronelal menggunakan atmosfir gas N2 dan/atau H2 dalam waktu 5 dan 24 jam masing-masing pada suhu 90 dan 120 C. Komposisi katalis, pemilihan jenis atmosfir gas dan suhu sangat berpengaruh terhadap aktivitas dan selektivitas pembentukan produk isomerisasi dan hidrogenasi. Konversi (R)-(+)-Sitronelal tertinggi ditunjukkan oleh katalis A3=Ni/ZnBr2/?-Al2O3 (2:3) dengan kondisi reaksi selama 5 jam (4 jam N2 + 1 jam H2) pada suhu 90 Cdan 24 jam (4 jam N2 + 20 jam H2) pada suhu 120 C.

The influence of catalyst properties and characteristics of Ni and ZnBr2 catalysts impregnated in ?-Al2O3 on the activity and selectivity of (R)-(+)-Citronellal isomerisation and hydrogenation has been done. In this study, there were three sets of Ni and ZnBr2 in ?-Al2O3 with various composition, they were A1=Ni/ZnBr2/?-Al2O3 (3:2), A2=Ni/ZnBr2/?-Al2O3 (1:1), A3=Ni/ZnBr2/?-Al2O3 (2:3). The catalysts were characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area and SEM-EELS. The catalysts spesific surface area and porosity determined by adsorption-desorption of dinitrogen at 77 K. Pore distribution and volume were determined by the desorption isotherm at P/Po ? 0.3. The result showed that there was correlation between the catalyst characteristics and catalytic activity to (R)-(+)-Citronellal isomerisation and hydrogenation product. The activity test were performed in a mini fixed bed reactor with 0.5 g of catalyst and 3 mL of (R)-(+)-Citronellal using N2 and/or H2 gas atmosphere in 5 and 24 hours at each temperature 90 and 120 oC. The catalyst composition of the choice of gas atmosphere and temperature greatly influenced the activity as well as the selectivity of isomerisation and hydrogenation product formation. The highest conversion was achieved for A3=Ni/ZnBr2/?-Al2O3 (2:3) with complete conversion of (R)-(+)-Citronellal were obtained when it was running in 5 hours (4 hours N2 + 1 hour H2) at 90 oC and 24 hours (4 hours N2 + 20 hour H2) at 120 oC.


Keywords


catalitic activity; isomerisation and hydrogenation of (R)-(+)-Citronellal; Ni/ZnBr2/?-Al2O3 characterization

Full Text:

PDF

References


Arvela PM, Kumar N, Nieminen V, Sjoholm R, Salmi T & Murzin DY. 2004. Cyclization of citronellal over zeolites and mesoporous materials for production of isopulegol. J Catal 225: 155-169

Chuah GK, Liu SH, Jaenicke S & Harrison LJ. 2001. Cyclisation of Citronellal to Isopulegol Catalysed by Hydrous Zirconia and Other Solid Acids. J Catal 200: 352-359

Corma A & Renz M. 2004. Sn-Beta zeolite as diastereoselective water-resistent heteregeneous Lewis-acid catalyst for carbon-carbon bond formation in the intramolecular carbonyl-ene reaction. Chem Commun 2004: 550-551

Iftitah ED. 2010. One pot transformation of citronellal to menthol over Ni/?-Al2O3, J Appl Sci Res 7(5): 680-689

Iftitah ED. 2011. A tandem cyclization and hydrogenation of ()-Citronellal to Menthol over mixed ZnBr2/?-Al2O3 and Ni/?-Al2O3 catalysts. J Basic Appl Sci Res 1(7): 777-781

Iosif F, Coman S, Parvulescu V, Grange P, Delsarte S, de Vos D & Jacobs P. 2004. Ir-Beta zeolite as a heterogeneous catalyst for the one-pot - of citronellal to menthol. Chem Commun 2004: 1292-1293

Kropp PJ, Breton GW, Craig SL, Crawford SD, Durland WF, Jones JE & Raleigh JS. 1995. Surface-mediated reactions. 6. effects of silica gel and alumina on acid-catalyzed reactions. J Org Chem 60: 4146-4152

Mertens P, Verpoort F, Parvulescu AN, & De Vos D. 2006. Pt/H-beta zeolite as productive bifunctional catalysts for the one step citronellal-to-menthol conversion. J Catal 243: 7-13

Milone C, Gangemi C, Ingoglia R, Neri G & Galvagno S. 1999. Role of the support in the hydrogenation of citronellal on ruthenium catalysts. Appl Catal A: General 184: 89-94

Milone C, Gangemi C, Neri G, Pistone A & Galvagno S. 2000. Selective one step synthesis of (-)-menthol from (+)-citronellal on Ru supported on modified SiO2. Appl Catal A: General 199: 239-244

Milone C, Perri A, Pistone A, Neri G & Galvagno S. 2002. Isomerisation of (+)-citronellal over Zn(II) supported catalysts. Appl Catal A: General 233: 151-157

Nakatani & Kawashima. 1978. Synthesis of Isopulegol. Japan Patent Application. No. JP-A-53-116348

Nie Y, Chuah GK & Jaenicke S. 2006. Domino-cyclisation and hydrogenation of citronellal to menthol over bifunctional Ni/Zr-Beta and Zr-beta/Ni-MCM-41 catalysts, Chem Commun 2006: 790-792

Ravasio N, Poli N, Psaro R, Saba M & Zaccheria F. 2000. Bifunctional copper catalysts. Part II. Stereoselective synthesis of (-)-menthol starting from (+)-citronellal. Topic Catal 13: 195-199

Ravasio N, Zaccheria F, Fusi A & Psaro R. 2006. One pot selective hydrogenation and dynamic kinetic resolution over Cu/Al2O3: A way to (-)-menthol starting from low value mint oils. Appl Catal A : General 315: 114-119

Da Silva KA, Robles-Dutenhefner PA, Sousa EMB, Kozhevnikova EF, Kozhevnikov IV & Gusevskaya EV. 2004. Cyclization of (+)-citronellal to (-)-isopulegol catalyzed by H3PW12O40/SiO2. Catal Comm 5: 425-429

Yongzhong Z, Yuntong N, Jaenicke S & Chuah GK. 2005. Cyclisation of citronellal over zirconium zeolite beta, a highly diastereoselective catalyst to ()-isopulegol. J Catal 229: 404-413


Refbacks

  • There are currently no refbacks.