Catalytic conversion of fructose, glucose, and sucrose to 5-(hydroxymethyl)furfural and levulinic and formic acids in gamma-valerolactone as a green solvent

Qi, Long and Mui, Yiu Fung and Lo, See Wing and Lui, Matthew Y. and Akien, Geoffrey R. and Horvath, Istvan T. (2014) Catalytic conversion of fructose, glucose, and sucrose to 5-(hydroxymethyl)furfural and levulinic and formic acids in gamma-valerolactone as a green solvent. ACS Catalysis, 4 (5). pp. 1470-1477. ISSN 2155-5435

Abstract

The conversion of fructose, glucose, and sucrose to 5-(hydroxymethyl)furfural (HMF) and levulinic acid (LA)/formic acid (FA) was investigated in detail using sulfuric acid as the catalyst and gamma-valerolactone (GVL) as a green solvent. The H2SO4/GVL/H2O system can be tuned to produce either HMF or LA/FA by changing the acid concentration and thus allowing selective switching between the products. Although the best yields of HMF were around 75%, the LA/FA yields ranged from 50% to 70%, depending on the structure of the carbohydrates and the reaction parameters, including temperature, acid, and carbohydrate concentrations. While the conversion of fructose is much faster than glucose, sucrose behaves like a 1:1 mixture of fructose and glucose, indicating facile hydrolysis of the glycosidic bond in sucrose. The mechanism of the conversion of glucose to HMF or LA/FA in GVL involves three intermediates: 1,6-anhydro-beta-D-glucofuranose, 1,6-anhydro-beta-D-glucopyranose, and levoglucosenone.