5‐Hydroxymethylfurfural (HMF). A Review Focussing on its Manufacture

Abstract The acid‐catalysed dehydration of hexoses results in the formation of 5‐hydroxymethylfurfural (HMF). Fructose and inulin are especially good starting materials. A review is given of the many methods to produce HMF. The reaction kinetics are dealt with in the sections: raw material, hydrolysis and reversion, catalysts, reaction temperature and time, the concentration and the risk of polymerization and the solvent and HMF stability. Manufacturing processes are illustrated for fructose as the starting material: aqueous systems with homogeneous acid catalysis or those using ion‐exchangers as catalyst, systems using dimethyl sulfoxide as the solvent and those using other organic solvents. A short treatment is given on processes starting with glucose, work up procedures and the formation of levulinic acid and other in situ ‐formed HMF‐derivatives.