Solid superacid catalyzed fatty acid methyl esters production from acid oil

A solid superacid catalyst was evaluated for the production of fatty acid methyl esters (FAMEs) from acid oil containing about 60 wt.% free fatty acids. It was demonstrated that SO42-/ZrO2–TiO2/La3+ was an effective catalyst for simultaneous transesterification and esterification. The optimization of reaction parameters was performed, showing that maximum yield of above 90% could be obtained under the conditions that molar ratio of alcohol/oil was 15:1, catalyst amount was 5 wt.%, temperature was 200 °C and duration was 2 h. The catalyst was finally recycled and utilized for five times repeatedly with little loss in activity. The final products purified by molecular distillation were detected by GC–MS. The content of FAMEs reached 96.24%.