Characteristics of chromium based mixed oxide catalyst in biodiesel production

Abstract

Renewable energy from biodiesel or fatty acid methyl ester (FAME) has become important in recent decades as one of the promising alternative for petroleum-derived fuel. In this study, chromium based mixed oxide catalysts which are Cr/Ca oxide and Cr/Zn oxide were synthesized via precipitation method and used in the transesterification of cooking palm oil to produce FAME. The reactions were conducted in a batch reactor at temperature of 60 °C, methanol:oil molar ratio of 6:1 and catalyst loading of 1wt%. The characterization through N2 adsorption-desorption showed BET-surface area, pore volume and pore size of Cr/Ca oxide are 3.6915 m2/g, 0.00684 cm3/g and 93.919Å, respectively while for Cr/Zn oxide are 3.9897 m2/g, 0.00630 cm3/g and 80.113Å, respectively. Both catalysts showed similar type isotherm which are type IV and hysterisis loop H3. The catalyst Cr/Ca oxide is found to be more active in the transesterication whereby FAME content of 27.8% was achieved compared to 7.4% by utilizing Cr/Zn oxide. The results showed that Cr/Ca oxide catalyst and Cr/Zn oxide have potential as heterogeneous catalyst to produce FAME from palm oil.