Preparation of Supported Phosphotungstic Acid Catalysts and Their Activity In Fructose Dehydration to 5-hydroxymethylfurfural

Using MCM-41、 HZSM-5 and mordenite(MOR) as carriers,phosphotungstic acid as active components,a set of molecular sieve supported phosphotungstic acid catalysts were prepared by a wet impregnation method.The supported phosphotungstic acid catalysts was characterized by Fourier-transform infrared spectroscopy、 X-ray diffraction,low temperature nitrogen adsorption-desorption technique and NH3-Temperature Programmed Desorption respectively.The results indicated that the frameworks of the carriers were not destroyed during loading,PW was highly dispersed on the surface of the carriers with amorphous structure,strong interaction was occurred between PW and the carriers.The supported phosphotungstic acid catalysts were evaluated as catalysts for the dehydration of fructose to 5-hydroxymethylfurfural(5-HMF),due to its more acid amount and appropriate pore size,the catalyst of PW/HZSM-5 shows superior catalyst activity and selectivity to 5-HMF comparing to the others supported phosphotungstic acid catalysts.With PW/HZSM-5 catalyst,fructose conversion of 96.5% with selectivity to 5-HMF of 79.9% were attained at 120 ℃ for 80 min reaction time in dimethylsulfoxide.