Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-I-16KINETICS IN THE HYDROGENATION OF β-SITOSTEROLTO β-SITOSTANOL OVER DIFFERENT Pd CATALYSTSP. Mäki-Arvela, G. Martin, A. Tokarev, N. Kumar, J. Hemming, B. Holmbom,T. Salmi, D.Yu. MurzinProcess Chemistry Centre, Åbo Akademi University, FI-20500 Turku/Åbo, FinlandIntroductionNowadays, one of the most important problem for human health is high concentration offats in food. Therefore, a lot of attention has been devoted to β-sitostanol, which was proved toinhibit cholesterol absorption [1], and is thus a constituent of some margarines available on theconsumer market. The aim of the present work was to evaluate the catalytic activity of severalmaterials in the hydrogenation of β-sitosterol, which is a product from pulping industry, in orderto achieve a high selectivity towards β-sitostanol and to determine the reaction kinetics over themost promising catalyst. The main reaction scheme is presented in Fig 1.C 2H 5C 2H 5Fig. 1. Reaction scheme for β-sitosterol hydrogenation.ExperimentalThe kinetic experiments were performed in a shaking reactor using 1-propanol as asolvent. The volume of the liquid phase was 110 mL and the pressure was set to4 bar. The raw material according to results obtained from GC-MS analysis were:82 wt.% β-sitosterol, about 7 wt.% campesterol, 9 wt.% β-sitostanol and 1 wt.% campestanol.The β-sitosterol hydrogenation was carried out in the presence of 1-propanol, and severalsupported Pd catalysts. The samples were withdrawn periodically from the reactor whichoperated at 60°C to 80°C. After addition of an internal standard solution consisting ofheneicosanoic acid and betulinol, the reaction mixture was evaporated under nitrogen andsilylated at 60°C for 45 min with BSTFA-TMCS-pyridine solution and analyzed by a GCequipped with an HP-1 column. Several catalyst characterization methods (COchemisorption,nitrogen adsorption, XRD) were applied. Furthermore, rapid UV analyseswere applied for the reaction mixtures, being prior calibrated using GC analyses.56