2017 Volume 96 Issue 1 Pages 1-7
It is reported that high quality biodiesel named HiBD, which are the mixture of aliphatic hydrocarbons, can be obtained by catalytic cracking of oils and fats through decarboxylation reactions of triglycerides and fatty acids over MgO/SiO2 and MgO/carbon catalysts. In this study, in order to make clear effect of carrier materials and MgO loading several MgO catalysts were prepared using different type of carrier materials and loadings, and examined catalytic performance for HiBD production. Selectivity to hydrocarbons of diesel fraction increased with increasing specific surface area and volume of SiO2 support. Extent of the secondary cracking of the hydrocarbons generated was influenced by the particle size of SiO2; larger particle size inhibited the reaction. It is suggested that formation of ketones, as possible intermediates from fatty acids to hydrocarbons, should be suppressed over SiO2 supports with pore sizes smaller than 30 nm. Higher selectivity to the diesel fraction was obtained over carbon supported catalysts with higher specific surface area. Also higher decarboxylation activity was observable, which suggests that carbon support itself has the catalytic activity with different reaction mechanisms. Higher loading of MgO promoted the direct decarboxylation as well as ketone generation from the fatty acids, and the maximum selectivity to hydrocarbons and CO2 yield were obtained with a loading of 30 wt% over SiO2-supported catalysts.
