The influence of the initial and catalyst concentrations on the dehydration of d-fructose

Abstract

The dehydration at 95° of d-fructose (0.25 m-1.0 m) to 5-hydroxymethyl-2-furaldehyde (HMF) and the rehydration of HMF (0.25-1.0 m) to levulinic and formic acids in 0.5-2 m HCl has been studied. The conversion rate of d-fructose was proportional to the Hammett activity. The acidity had a smaller influence on the conversion rate of HMF, although it was not proportional to the catalyst concentration. The rehydration of HMF was faster in the presence of d-fructose. The yield of levulinic acid was independent of the catalyst concentration, but was lower at higher initial concentrations of d-fructose and HMF, and a kinetic model has been derived. The formation of humin was of an overall order 1.3 in an intermediate between d-fructose and HMF, and of an order 1.7 in an intermediate between HMF and levulinic acid.