CARDOSO, R. K. P.; http://lattes.cnpq.br/9692883856349091; CARDOSO, Raquel Kethy Patrício.
Résumé:
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.