Highly efficient procedure for biodiesel synthesis using polypyrrole functionalized by sulfonic acid

A novel polypyrrole functionalized by sulfonic acid was synthesized by the polymerization of N-butanesulfonic acid pyrrole using chemical oxidation. The catalytic activity of the solid acid was investigated in the transesterification of rapeseed oil. The results showed that the solid acid was very efficient in this reaction with a yield of 99%. Both the free fatty acids and triglycerides could be transformed to the methyl esters using the solid acid. Moreover, the water content in the raw material had little effect on the catalytic activity of the solid acid. The solid acid was characterized by operational simplicity, low cost, high acidity and good catalytic activity, indicating potentiality for using in “green” chemistry.