Continuous production of 5-hydroxymethylfurfural: A catalyst-free approach using non-toxic solvents for pharmaceutical applications

This work aimed to develop the continuous 5-HMF production process from cane syrup for pharmaceutical applications. A catalyst-free process and a non-toxic solvent were implemented to achieve a cost-effective production process with considerations of safety and environmental impacts. This work studied the roles and influences of various non-toxic organic solvents on production performance and cost. The most common effective solvent (methyl isobutyl ketone) was used as a benchmark. The effects of various operating conditions on the 5-HMF yield and 5-HMF productivity were investigated and optimized based on an experimental design using the most suitable solvent selected. The 5-HMF yield of 66.8 % and 5-HMF production rate of 9.35 × 10⁻⁶ kg/h were achieved under the reaction temperature of 190 °C, residence time of 80 min, syrup feed concentration of 25 g/L, and organic-to-aqueous volumetric ratio of 1:1. The satisfactory 5-HMF yield and reasonable 5-HMF production were observed when compared to other processes obtained from the literature. The feasibilities for improving this process was also discussed.