STUDY OF THE APPLICATION OF Mo/SBA-15 AND Ni/SBA-15 CATALYSTS, PREPARED BY MICROWAVE HEATING, IN THE SYNTHESIS OF BIODIESEL

Abstract

This work aimed to produce 5% (w/w) molybdenum and nickel catalysts, supported in SBA-15 molecular sieve, and evaluate their application in the synthesis of biodiesel. The catalysts were prepared by physical dispersion and were characterized by X-ray diffraction, X-ray energy dispersion spectrophotometry, and N2 adsorption-desorption. Transesterification reactions were carried out to evaluate the activity of the catalyst. The synthesis was effected by using a system comprised of a polytetrafluoroethylene batch reactor jacketed with a piece of stainless steel working at 600 rpm. The reactions were conducted at 473K for 4 hours, using a soybean oil/ethanol molar ratio of 1/12, and 5% of catalyst based on the mass of oil used. After characterization, the catalysts were subjected to catalytic tests to check the reaction conversion parameters obtained by gas chromatography. The kinematic viscosity and density of the biodiesel samples were then determined. The chromatography results were not satisfactory for the test with SBA-15 (pure silica). The conversion to esters obtained was 5%, which can be due to the formation of silanol groups (Si-OH) on the silica surface, which are considered Bronsted acidic sites. However, in terms of strength, the acidity of silanol is usually either low or moderate. Mo/SBA15 and Ni/SBA-15 catalysts yielded conversions to biodiesel as high as 96.57% and 84.67%, respectively.