改性丝光沸石催化果糖脱水制备5-羟甲基糠醛

Dehydration of Fructose to 5-Hydroxymethylfurfural Catalyzed by Modified Mordenite

分别采用酸处理、碱处理及氨基化处理对丝光沸石(HMOR)进行改性后制备了系列HMOR催化剂,采用X射线衍射(XRD)、氨程序升温脱附(NH 3-TPD)、傅里叶红外光谱(FT-IR)、X射线荧光(XRF)等手段对HMOR进行表征,并采用间歇式不锈钢高压反应釜考察其催化果糖脱水生成5-羟甲基糠醛(HMF)反应性能。结果表明:改性后催化剂仍保持丝光沸石的晶体结构,酸中心强度与酸量有改变,硅烷化试剂3-氨丙基三乙氧基硅烷(APTES)中的氨基基团成功嫁接到丝光沸石表面;得到了较优反应条件:N 2压力2.0 MPa,反应温度150℃,果糖质量1.0 g,催化剂质量0.2 g,助剂聚乙烯吡咯烷酮质量0.06 g,反应时间180 min。在此反应条件下,以氨基化处理改性制备的NH 2-MOR 0.5为催化剂时,果糖转化率84.1%,HMF产率78.6%,HMF选择性93.4%;与其他催化剂相比,虽果糖转化率略微下降,但HMF选择性明显提高。

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(NH 3-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 NH 2-MOR 0.5 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.