Dehydration of Fructose to 5-Hydroxymethylfurfural Catalyzed by Modified Mordenite
A series of catalysts were prepared by modifying mordenite(HMOR)with acid,base and amination treatment.Then the HMOR catalyst was characterized by X-ray diffraction(XRD),ammonia temperature programmed desorption(NH3-TPD),Fourier transform infrared spectroscopy(FT-IR),and X-ray fluorescence(XRF).The catalytic performance of HMOR catalyst for fructose dehydration to 5-hydroxymethylfurfural(HMF)was investigated in an intermittent stainless steel high-pressure reactor.The characterization results show that the modified catalyst still maintains the crystal structure of mordenite,with changes in acid center strength and acid content.The amino groups in the silylation reagents(3-aminopropyltriethoxysilane,APTES)are successfully grafted onto the surface of mordenite.Under the optimal reaction conditions:nitrogen pressure 2.0 MPa,reaction temperature 150 ℃,fructose 1.0 g,catalyst 0.2 g,cocatalyst polyvinylpyrrolidone 0.06 g,and reaction time 180 min,using NH2-MOR0.5 modified by amination treatment as catalyst,the fructose conversion,HMF yield and HMF selectivity are 84.1%,78.6%and 93.4%,respectively.Compared with other catalysts,although fructose conversion slightly decreases,HMF selectivity is significantly improved.