L 酸/B 酸可调的磺酸功能化 MIL-101（Cr）材料催化葡萄糖脱水制备5-羟甲基糠醛

摘要

A series of Cr-terephthalates metal-organic frameworks functionalized by sulfonic acid group (−SO3H) [MIL-101(Cr)-SO3H], featuring varied ratios of Lewis acid site to Brönsted acid site, were synthesized by hydrothermal reaction method starting from Cr(NO3)3·9H2O and sodium 2-sulfoterephthalate under various conditions of temperature and reaction time. The catalysts were characterized by techniques of PXRD, EDX, SEM, ICP-AAS and BET surface area, and the catalytic performances for glucose conversion to 5-HMF were evaluated. It showed that, in terms of the catalysis kinetics, Cr3+ serves as the Lewis acid sites of MIL-101(Cr)-SO3H for glucose isomerization, and sulfonic acid group, the Brönsted acid site for the fructose dehydration. The highest HMF selectivity of 47.15% and the highest HMF yield of 46.0% was achieved under conditions of molar ratio of Brönsted acid site to Lewis acid site of 1.1, 150℃ for 2 h.%以九水合硝酸铬和单磺酸钠对苯二甲酸为原料，水为溶剂，采用水热法合成系列磺酸功能化 MIL-101(Cr)，通过调节反应温度和时间，合成不同 Lewis/Brönsted 催化位点比例的磺酸功能化 MIL-101(Cr)，采用 PXRD、EDX、SEM、ICP-AAS 及 BET 比表面积分析等技术对材料进行综合表征，并研究磺酸功能化 MIL-101(Cr)催化葡萄糖脱水制备5-羟甲基糠醛的催化活性。催化反应动力学研究结果表明，MIL-101(Cr)-SO3H 中的 Cr(Ⅲ)作为葡萄糖异构化反应的 Lewis 酸位点，－SO3H 作为果糖脱水反应的 Brönsted 酸催化位点，当催化剂的 Brönsted 酸和 Lewis 酸的摩尔比为1.1时，150℃下反应，5-羟甲基糠醛的选择性最高可以达到47.15%，5-羟甲基糠醛的产率最高达到46.0%。