Influence of the milling process on the structure and morphology of ZnAl₂O₄ and catalytic performance in the methyl transesterification reaction of soybean oil

This work aimed to evaluate the effect of milling time over the structure and morphology of ZnAl₂O₄, synthesized by combustion reaction, and study the effect of milled samples over the methyl transesterification reaction of soy bean oil. ZnAl₂O₄ was synthesizing, by means combustion reaction, using a electrical resistance plate. The powder was milled over 15, 30, 45 and 60 minutes and the samples were characterized by X-ray diffraction, scanning electron micrograph, particle size distribution and N₂ adsorption isotherms. Milling process promoted changes over the agglomerate size and textural characteristics of the samples. Catalytic tests were conducted at 160 deg C, with 1% of catalyst, with molar ratio oil:methanol of 1:6 and reaction time of 1 hour. According the results, the sample milled over 30 minutes showed the highest conversion. (author)