Preparation of Biodiesel Based on Alkaline Ionic Liquid [Bmim]OH Catalyzed Castor Oil

Abstract

In this experiment, a new basic ionic liquid [Bmim]OH was synthesized from 1-methylimidazole and sodium hydroxide, which was used to catalyze the preparation of biodiesel from castor oil. The catalyst of [Bmim]OH was compared with KOH and tetrabutylammonium hydroxide during the study. The experimental results showed that the latter two were better than the latter two. The orthogonal experimental design scheme was used to optimize the process conditions. The optimized catalytic conditions of alkaline ionic liquid [Bmim]OH were as follows: the catalyst dosage was 1%, the molar ratio of alcohol to oil was 6:1, the reaction temperature was 40 °C, and the reaction time was 60min. Under the optimized conditions, the crude methyl ester mixture yield is higher than 97%, the castor oil is more than 95% converted to the product methyl ester, and the catalyst of [Bmim]OH is used for six times without significant consumption, and the catalytic performance is stable.