Catalytic dehydration of glucose to 5-HMF using heterogeneous solid catalysts in a biphasic continuous-flow tubular reactor

This work aimed to produce 5-hydroxymethylfurfural (5-HMF) from glucose in a biphasic continuousflow tubular reactor with various heterogeneous solid acid catalysts or combined solid acid-base catalysts. Among the catalysts tested, niobium phosphate (NbP) was found to be the most active catalyst for glucose dehydration with a maximum 5-HMF yield of 45% at 150 degrees C. The higher activity of NbP was attributed to its higher total number of acid sites and BET surface area, as well as the presence of both Lewis acid and Bronsted acid sites. The effects of different operating conditions such as aqueous to organic (A/O) phase ratio, reaction temperature and feeding flow rate on the activity of some selected catalysts were studied. Reducing A/O ratio by increasing the extracting organic phase flow rate and increasing the reaction temperature (up to 150 degrees C) were found to positively affect 5-HMF production from glucose in the presence of NbP. Kinetics study demonstrated that the overall reaction of glucose dehydration to 5-HMF over the NbP catalyst is a first-order reaction with the reaction rate constants (k) determined as 0.06, 0.21 and 0.6 min(-1) at 110, 130 and 150 degrees C, respectively, and the apparent activation energy (Ea) calculated to be 77 kJ/mol. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

This study aimed to produce 5-HMF from glucose using NbP catalyst in a biphasic continuous flow reactor, achieving high yield and demonstrating the benefits of reducing A/O ratio and increasing reaction temperature for the catalytic reaction. The kinetics study showed that the glucose dehydration reaction to 5-HMF over NbP catalyst is a first-order reaction.