Dehydration of Glucose to 5-Hydroxymethylfurfural Using LaOCl/Nb2O5 Catalysts in Hot Compressed Water Conditions

The dehydration of fructose and glucose to 5-hydroxymethylfurfural was studied using LaOCl/Nb2O5 in hot compressed water conditions. The catalysts were prepared by impregnation of LaCl3 on Nb2O5 with different loadings. The solids were characterized by EDX, XRD, TGA and N-2 physisorption at 77 K and pyridine and CO2 adsorption followed by FTIR; the strength of acidity and basicity was determined by NH3-TPD and CO2-TPD, respectively. The use of acid-base systems for HMF production mainly from glucose requires weak basic sites and moderate acidity condition that is reached with LaOCl/Nb2O5 as was confirmed by acidity and basicity analyses. The presence of Nb2O5 increase HMF yield (> 50%) and prevented the formation of undesirable products in hot compressed water conditions, similar results could be obtained with DMSO.