Study on the conversion of carbohydrates to 5-hydroxymethylfurfural using catalysts bearing Brønsted and Lewis acid in green chemistry conditions

Abstract

5-Hydroxymethylfurfural (HMF) serves as a prospective intermediary in the synthesis of biofuels. In recent years, researchers have sought environmentally friendly methodologies and appropriate catalysts for the synthesis of HMF under green chemistry conditions. In this study, we synthesized three ionic liquids containing Brønsted acid/Lewis acid centers and one biomass-derived catalyst with Brønsted acid groups from biomass. The efficacy of two types of catalysts was utilized in the procedure for converting carbohydrates into HMF. The research examined the effects of temperature, catalyst mass, recovery, and reuse to identify optimal conditions for the synthesis of HMF. The findings indicated that the 1-(4-sulfonic acid) butyl-3-methylimidazolium zinc chloride (IL3) catalyst exhibited enhanced activity relative to alternative catalysts, achieving a reaction yield of around 88% HMF in 2 hours using EMIMCl as a solvent. The Brønsted acid-based solid catalyst achieved a reaction yield of 52% HMF using 5 mg CA-SO₃H for a duration of 5 hours. This study illustrates the feasibility of synthesizing HMF from fructose utilizing green catalysts (ionic liquids or carbon-based solid acid ), suitable for large-scale production and particularly as a foundational platform for generating biomass-derived biofuels under green chemistry principles.