Avaliação do efeito das razões Si/Mo e óleo/álcool na produção de biodiesel a partir do óleo de soja.

Abstract

Biodiesel is a biofuel obtained from renewable sources that emerged as an alternative to the use of petroleum diesel for internal combustion engines. It can be obtained by the transesterification reaction of triglycerides present in vegetable oils, animal fats and oleaginous plants, and short-chain alcohols via homogeneous or heterogeneous catalysis. This reaction is carried out in the presence of acidic, basic or enzymatic catalysts. Heterogeneous catalysts are efficient and reduce operating costs in the production processes of this biofuel. Therefore, this work aimed to evaluate the influence of the reaction conditions oil/alcohol and Si/Mo ratios on the biodiesel yield obtained by transesterification of soybean oil using a new catalyst (x_Mo-KIT-6). The x_Mo-KIT-6 catalysts were obtained by direct hydrothermal synthesis using different Si/Mo molar ratios (10, 20, 30). A 22

+ 3PtCt factorial design was used to evaluate the influence of oil/alcohol and Si/Mo ratios on biodiesel yield. The diffractograms showed an increase in the unit cell parameter (a0) with increasing molar ratio (Si/Mo) and that a smaller amount of molybdenum results in the formation of a well-organized cubic symmetry catalyst. The FTIR spectra of the catalysts indicated different stretching vibrations of molybdenum. The textural properties of 20_Mo-KIT-6 catalyst are more stable. ANOVA statistical analysis shown that Si/Mo ratio was the most significant variable. The factorial design showed that the optimal conditions for maximizing the biodiesel yield are: using the 10_Mo-KIT-6 catalyst, and an oil/alcohol ratio of 1/20 at 150 oC for 3 hours. However, using the 20_Mo-KIT-6 catalyst with an oil/alcohol ratio of 1/15, the biodiesel yield is close to the maximum yield, having the advantage of using a lower amount of methanol, which means that the alcohol separation of non-reacted alcohol will consume less energy.