Produção de ésteres etílicos de ácidos graxos através da reação de esterificação

Abstract

Biodiesel is a renewable and less toxic alternative, produced mainly by the transesterification of refined vegetable oils, to reduce production costs with a raw material, other sources of oils are being studied. The great difficulty in producing biodiesel from alternative raw materials is like high concentrations of free fatty acids (FFA), which makes the use of alkaline catalysts unfeasible. Homogeneous alkaline catalysts, which are being widely used in the production of biodiesel, are toxic, highly flammable and corrosive, and in the use of low quality oils with high content of fatty acids, cause reaction saponification, reducing the yield of reaction. Thus, heterogeneous catalysts can be used to replace homogeneous catalysts, preventing the formation of soaps separated by filtration, reducing environmental damage. The aim of this work is the production of ethyl esters of fatty acids (biodiesel), through the conversion of the free fatty acids from the soybean oil distillation, using the ethanol for an esterification reaction and Amberlyst® 15 as a catalyst, a design of experiments completed 23 was realized. The experiment at 90 °C, 1:1 molar ratio and 3% catalyst was the one that obtained a better conversion, of 24.94% conversion of the FFA, already experiment conducted at 90 °C, 1:5 e 3% of catalyst presented 22.80%, presenting values slightly lower than the experiment both in 2 h of reaction. The variables, catalyst and temperature, and an interaction between them showed significant influence on the esterification reaction.