Microwave Assisted Synthesis of 5-Hydroxymethylfurfural from Starch in AlCl3•6H2O/DMSO/[BMIM]Cl System

A successful protocol has been developed for the microwave assisted conversion of corn starch into 5-hydroxymethylfurfural (HMF): utilizing aluminum chloride hexahydrate (AlCl3 center dot 6H(2)O) and 1-butyl-3-methylimidazolium chloride ([BMIM] Cl) ionic liquid. HMF yield as high. as 59.8 wt % was achieved at 150 degrees C within a short reaction time of 20 min. The dimethyl sulfoxide (DMSO)/[BMIM]Cl system was found to be tolerant to optimal water content which influenced the product distribution. Levulinic acid was detected in negligible quantities, and humin content could be controlled by varying different process parameters. Satisfactory results were achieved when waxy corn starch (HMF yield 64.9 wt %) and high amylose corn starch (HMF yield 51.1 wt %) were compared as potential feedstock alternatives to fructose and glucose. The work provided significant insight into the synthesis of HMF in a microwave environment from sustainably sourced biomass such as starch having high amylopectin content.