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

### **Jéssica Siqueira Mancilha Nogueira 1, João Paulo Alves Silva 1, Solange I. Mussatto 2 and Livia Melo Carneiro 1,\***


Received: 22 December 2019; Accepted: 26 January 2020; Published: 4 February 2020

**Abstract:** 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 ◦C), type of support (Nb2O5 or Al2O3), and active phase (H3PW12 O40—HPW or H3PMo12 O40—HPMo) were tested and combined based on Taguchi's L8 orthogonal array. As a result, HPW-Nb2O5 calcined at 300 ◦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, di fferent temperatures (160 or 200 ◦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 L16 experimental design. The conditions that resulted in the highest HMF yield (40.8%) consisted of using 50 g/<sup>L</sup> of glucose at 160 ◦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%).

**Keywords:** 5-hydroxymethylfurfural; glucose; heteropolyacid catalysts
