N-Butyl levulinate synthesis using lipase catalysis: comparison of batch reactor versus continuous flow packed bed tubular microreactor

Abstract

Levulinic acid and its derivatives have applications in the synthesis of various organic chemicals because of the presence of carboxylic acid and ketone functional groups in the same moiety. Levulinate esters have potential applications in biodiesel as blending components, and fragrance and flavor industries. In the present work, n-butyl levulinate was synthesized by different commercial immobilized lipases such as Rhizomucor miehei lipase (RM IM), Thermomyces lanuginosus lipase (TL IM) and Novozym 435 using a continuous flow packed bed tubular microreactor and also a stirred tank batch reactor. Novozym 435 was the best catalyst. The continuous flow tubular microreactor gave 85% conversion of levulinic acid in 2 min at 60 °C when mole ratio 1: 3 of levulinic acid to n-butanol was used in methyl tert-butyl ether (MTBE) as solvent. The batch reactor needed 2 h to achieve the same conversion thereby proving superiority of the continuous flow reactors.