Synthesis and Application of Heterogeneous Catalysts Based on Heteropolyacids for 5-Hydroxymethylfurfural Production from Glucose

This study aimed to evaluate the synthesis and application of heterogeneous catalysts based on heteropolyacids for 5-hydroxymethylfurfural (HMF) production from glucose. Initially, assays were carried out in order to establish the most favorable catalyst synthesis conditions. For such purpose, calcination temperature (300 or 500 degrees C), type of support (Nb2O5 or Al2O3), and active phase (H3PW12O40-HPW or H3PMo12O40-HPMo) were tested and combined based on Taguchi's L-8 orthogonal array. As a result, HPW-Nb2O5 calcined at 300 degrees C was selected as it presented optimal HMF production performance (9.5% yield). Subsequently, the reaction conditions capable of maximizing HMF production from glucose using the selected catalyst were established. In these experiments, different temperatures (160 or 200 degrees C), acetone-to-water ratios (1:1 or 3:1 v/v), glucose concentrations (50 or 100 g/L), and catalyst concentrations (1 or 5% w/v) were evaluated according to a Taguchi's L-16 experimental design. The conditions that resulted in the highest HMF yield (40.8%) consisted of using 50 g/L of glucose at 160 degrees C, 1:1 (v/v) acetone-to-water ratio, and catalyst concentration of 5% (w/v). Recycling tests revealed that the catalyst can be used in four runs, which results in the same HMF yield (approx. 40%).