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

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%。

Sulfonic acid functionalized MIL-101(Cr) catalysts with tunable Lewis acid and Brönsted acid sites for glucose dehydration to 5-HMF

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.