ZrOCl2·8H2O： An Efficient and Cheap Catalyst for Esterification of Free Fatty Acids to Methyl Esters

The esterification of lauric acid with methanol could be efficiently catalyzed by ZrOCl2·8H2O, and this reactionwas studied to develop a green method for biodiesel production. The influencing factors, such as amount of catalyst, reactiontime and molar ratio of acid to methanol, were investigated. The results indicated that the ZrOCl2·8H2O catalyst showedhigh catalytic activity, and gave a 97.0% methyl laurate conversion rate under the following optimized conditions, viz.： alauric acid/methanol molar ratio of 1：10, a catalyst dosage of 4%, and a reaction duration of 2 h at methanol refluxing temperature.The catalyst could be easily recovered while its activity could be well retained after three cycles. The ZrOCl2·8H2Ocatalyst also exhibited excellent catalytic activity for the esterification of different free long-chain fatty acids （including nonedibleoils with high acid value） with different short carbon chain alcohols. Therefore, the ZrOCl2·8H2O catalyst has goodpotential for the synthesis of biodiesel from low-cost feedstocks such as waste vegetable oils and non-edible oils.