Microwave synthesis of alkyl levulinates using a Keggin heteropolyacid from the cellulose of Eichhornia crassipes

Abstract

Alkyl levulinates were synthesized directly from cellulose derived from water hyacinth (Eichhornia crassipes) using a Keg-gin heteropolyacid under microwave-assisted hydrolysis. The pretreatment method to obtain cellulose was identified as a keyfactor to achieve higher yields of butyl levulinate. Hydrothermal pretreatment with H2SO4 resulted in the highest celluloseyield, with minimal hemicellulose and lignin content, the highest crystallinity index, and reduced water adsorption, all con-tributing to an increased yield of butyl levulinate. Additionally, the use of longer-chain alcohols, such as pentanol, furtherenhanced the yield, indicating that solvent polarity significantly impacts on alkyl levulinate production.