Characterization and Efficiency of ZnAl_2O_4 Spinel Synthesized by Combustion Reaction on the Esterification and Transesterification of Soybean Oil

摘要

This paper proposes to assess the efficiency of ZnAl_2O_4 obtained by combustion reaction on the process of esterification and transesterification of soybean oil to biodiesel production. In the synthesis it was used three heating conditions: spiral resistance, muffle furnace, and microwave oven. In order to investigate the influence of the heating source on the structure, morphology, and on the catalytic activity, the samples were characterized by XRD, FTIR, granulometric analysis, TGA, carbon content, TEM, and gas chromatography. The results showed that it was possible to obtain the ZnAl_2O_4 cubic phase with traces of ZnO. The ZnAl_2O_4 monophasic was just obtained by the synthesis carried out in the microwave oven and in the electrical resistance. All the samples showed a typical morphology of dense agglomerates and low carbon content. The samples also presented low catalytic activity in the esterification and transesterification process under the adopted conditions.