Synergetic oxidative esterification of 5-hydroxymethylfurfural using Pd-Au bimetallic nanocomposite under mild conditions

Abstract

An innovative Pd and Au nanoparticles (NPs) supported polymeric matrix (PdAu@PS) as stable, heterogeneous and recyclable nanocomposite was developed for oxidative esterification of 5-hydroxymethylfurfural (5-HMF) to dimethyl-2,5-furandicarboxylate (DMFC) and methyl-5-(hydroxymethyl)furan-2-carboxylate (MHFC). The prepared nanocomposite offered DMFC (48% selectivity) and MHFC (50% selectivity) in maximum 94% conversion with 98% overall selectivity at 35 °C temperature under mild reagent conditions. In this catalytic conversion, the inter-electronic interactions existing between Pd and Au metals were proved to be responsible for extraordinary stability, reactivity and recyclability of the catalyst. The identification of intermediates through mass spectrometry and the insight of control experiments helped us in concluding the possible reaction pathway. Importantly, the bimetallic catalyst was excellently recycled for six cycles with slight loss in conversion and selectivity.