Transformation of 5-Hydroxymethylfurfural (HMF) to Maleic Anhydride by Aerobic Oxidation with Heteropolyacid Catalysts

Abstract

Developing novel technologies to utilize renewable biomass as the source of energy and carbon to partially replace the fossil resources has been well recognized by the global governments and both industrial and academic communities. This work explored a catalytic transformation of biomass-based 5-hydroxymethylfurfural to maleic anhydride and maleic acid through aerobic oxidation with vanadium-substituted heteropolyacid. Under the optimized conditions, total yields of 64% for maleic anhydride and maleic acid could be achieved. Mechanistic studies with control experiments excluded 2, 5-furandicarboxylic acid, 2, 5-diformylfuran, 5-formyl-2-furancarboxylic acid, and 5-hydroxymethyl-2-furancarboxylic acid as the intermediates in the pathway of 5-hydroxymethylfurfural oxidation to maleic anhydride. Alternatively, a new mechanism initialized by the C–C bond cleavage between the hydroxymethyl group and furan sketch of HMF by heteropolyacid has been proposed for MA formation, in which several intermediates have b...