Efficient synthesis of biodiesel over a recyclable catalyst comprising a monolacunary silicotungstate and zeolite Hβ

Abstract

This paper presents a study of esterification of oleic acid as well as transesterification of soybean oil with methanol over a solid acid catalyst comprising a monolacunary silicotungstate anchored to zeolite Hβ. The optimization of the reaction parameters were carried out to get the maximum conversion. The 3.5 wt% catalyst charge at 60 °C showed 82% conversion of oleic acid with a 1 : 20 mole ratio of acid to alcohol in 10 h whereas the 4 wt% catalyst charge at 65 °C showed 96% conversion of soybean oil with a ratio of oil to alcohol of 1 : 4 (w/w) in 8 h. The catalyst was found to be readily reusable and exhibited consistency in activity upon reuse four times without appreciable loss in the conversion.