Glucose conversion to 5-hydroxymethylfurfural- pH enhanced product formation using CrCl2 in liquid water

The effect of liquid water pH on the conversion of glucose to 5- hydroxymethylfurfural (HMF) catalysed by CrCl2, CoCl2, CuCl2, SnCl2 and FeCl3 respectively has been studied at 373 K using UV/Vis Spectrophotometry. Absorbance values of HMF in the different study solutions were used for its quantification. Best yields of HMF were obtained with CrCl2 and CuCl2 with absorbance values of 0.687 and 0.284 respectively. The effect of liquid water pH using CrCl2 as catalyst for glucose conversion to HMF gave a geometric increase in HMF yield above pH of 9. This result suggests that optimum conversion of glucose to HMF in liquid water is effective in alkalinemedia using CrCl2. Studies on the kinetics of the reaction at pH12 using CrCl2 as catalyst, gave maximum product yield in 40 minutes at the study conditions. The rate data obtained indicated that the reaction is a unimolecular first order process with rate constant 6.5 10-6 s-1.