Challenges of phosphate and carbonate salts as catalysts for biodiesel synthesis

The catalytic activity of tribasic phosphate and dibasic carbonate supported on treated silica or alumina was studied. A simple method was developed for facilitating the dispersion of solid catalyst particles in the reaction mixture. Fatty acid methyl esters (FAMEs) was undertaken based on a common procedure. Methyl esters were included in the starting mixture to serve as an emulsifier. An emulsifier was chosen to facilitate catalyst and oil contact. Tribasic phosphate and dibasic carbonate salts proved sufficiently basic for the conversion. The tests also revealed that these active salts are slightly soluble in the reaction mixture. The silica and alumina supports were used as received and were also subjected to two pretreatments to promote catalyst bonding, heat treatment and acid washing.