Cadmium Compounds as Catalysts for Biodiesel Production

Abstract

Divalent cadmium compounds, particularly CdO, were used as Lewis-acid catalysts in the hydrolysis, esterification, and transesterification of pure triacylglycerides or fatty acids obtained from neutralized soybean oil, as well as mixtures of these substrates. In more than one step, reaction yields of up to 98% in fatty acids or fatty acid methyl esters were achieved. To study the use of these reactions for the development of technologies for biodiesel production from low-grade starting materials, a study was also carried out using a real sample with a high content of free fatty acids from the Brazilian savanna palm-tree oil called Macauba (Acrocomia sclerocarpa M.). Using multistep, sequential, or combined (one-pot) reaction processes, it was possible to obtain an overall reaction yield of up to 98% in methyl esters.