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果糖催化脱水制5-羟甲基糠醛(5-HMF)是生物质转化制高附加值化合物过程中的一个重要反应。采用自制的介孔SBA-15,浸渍法制备了Nb/SBA-15催化剂,再经磷酸化处理制得Nb-P/SBA-15催化剂,研究了该催化剂在果糖脱水制5-HMF反应中的性能。SEM、TEM、BET和XRD表征结果表明,Nb/SBA-15和Nb-P/SBA-15完好地保留了SBA-15的微观结构,其内孔道直径为10 nm,铌酸在孔内表面分布均匀;负载铌和磷酸化后,孔壁变薄。NH3-TPD结果显示,Nb/SBA-15经磷酸预处理后,不仅弱酸性位有所增加,而且产生了中强酸和强酸性位,使得在含水两相体系果糖脱水反应中,Nb-P/SBA-15比Nb/SBA-15具有更高的催化活性和5-HMF选择性。同时考察了反应温度、溶剂比例、反应时间对果糖脱水的影响,结果表明,以水/MIBK(V/V=1/2)为溶剂时,160℃下反应1.5 h,果糖转化率和5-HMF收率分别高达96.1%和92.6%。Nb-P/SBA-15经循环使用四次后仍具有较好的催化活性,表明该催化剂具有较高的耐水稳定性。
The catalytic dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) is an important reaction in biomass conversion to high value added compounds. The Nb-P / SBA-15 catalyst was prepared by the self-made mesoporous SBA-15 and impregnation method, and then the catalyst was prepared by phosphating. The effects of the catalyst on the 5-HMF reaction performance. The results of SEM, TEM, BET and XRD indicated that the microstructure of SBA-15 remained intact in Nb / SBA-15 and Nb-P / SBA-15 with an inner pore diameter of 10 nm. Even; niobium and phosphorylation load, pore wall thinning. NH3-TPD results showed that not only the weakly acidic sites but also the strong acids and strong acidic sites of Nb / SBA-15 pretreated with phosphoric acid make Nb-P / SBA-15 has higher catalytic activity and 5-HMF selectivity than Nb / SBA-15. The effects of reaction temperature, solvent ratio and reaction time on the dehydration of fructose were investigated. The results showed that under the conditions of water / MIBK (V / V = 1/2) HMF yield as high as 96.1% and 92.6%. Nb-P / SBA-15 still has good catalytic activity after being recycled for four times, indicating that the catalyst has high water stability.