A Facile Synthesis Route to AuPd Alloys for the Selective Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Furandicarboxylic Acid

Abstract

AbstractSynthesis of 2,5‐furandicarboxylic acid (FDCA) can be achieved via catalytic oxidation of 5‐hydroxymethylfurfural (5‐HMF), in which both base and catalyst play important roles. This work presents the development of a simple synthesis method (based on a commercial parent 10 wt.% Pd/C catalyst) to prepare the bimetallic AuPd alloy catalysts (i. e., AuPd/C) for selective 5‐HMF oxidation to FDCA. When using the strong base of NaOH, Pd and Au cooperate to promote FDCA formation when deployed either separately (as a physical mixture of the monometallic Au/C and Pd/C catalysts) or ideally alloyed (AuPd/C), with complete 5‐HMF conversion and FDCA yields of 66 % vs 77 %, respectively. However, NaOH also promoted the formation of undesired by‐products, leading to poor mass balances (<81 %). Comparatively, under weak base conditions (using NaHCO3), an increase in Au loading in the AuPd/C catalysts enhances 5‐HMF conversion and FDCA productivity (due to the enhanced carbonyl oxidation capacity) which coincides with a superior mass balances of >97 %. Yet, the excessive Pd content in the AuPd/C catalysts was not beneficial in promoting FDCA formation.