Microwave-assisted catalytic upgrading of bio-based furfuryl alcohol to alkyl levulinate over commercial non-metal activated carbon

A cheap and commercially available non-metal activated carbon (AC) as an efficient catalyst for the alcoholysis of furfuryl alcohol (FA) to alkyl levulinate (AL) under microwave assistance was firstly investigated. The catalyst gave an impressive methyl levulinate (ML) yield of 78% in only 5 min at 170 °C in the presence of FA (0.2 M, 3 mL) and AC (100 mg). Various reaction parameters in dependence of time such as temperature, catalyst and feedstock loadings as well as solvent types have been optimized. The re-utilization experiments of the catalyst showed that the activity related to the acidic groups of the catalysts, and the deactivation was due to the leaching of acidic specie, which was easily extracted by the solvent. Note that extremely low concentration of the active species extracted from AC (less than 1 wt %) could also give 62% ML yield. The present study provided a promising way for AL synthesis over cheap, commercially available and environmentally benign catalyst.