Zr-MOF空心纳米球固载离子液体对CO2环加成反应的催化性能

通过后合成修饰方法(PSM)构筑了空心纳米球(Void@UiO-66-Ⅰ)和实心块(UiO-66-Ⅰ) 2种形貌的季铵盐功能化UiO-66-NH₂(Zr), 得到兼具酸碱活性位点和氢键给体的新型功能化金属-有机框架材料. 通过一系列表征证明2种催化剂的成功合成, 并将它们用于催化转化CO₂和氧化苯乙烯的环加成反应. 由于Void@UiO-66-Ⅰ催化剂的季铵盐部分含有大量的羟基和卤素阴离子, 可以通过氢键和亲核攻击与环氧化合物连接, 诱导环氧化合物开环, 促使反应顺利进行, 且催化剂的中空结构有利于物质进出催化剂, 起到加快反应速率的作用, 使得该催化剂在CO₂与氧化苯乙烯环加成反应中表现出比实心块UiO-66-Ⅰ催化剂更好的催化性能. Void@UiO-66-Ⅰ催化剂在120 ℃, CO₂压力为1.2 MPa, 反应时间为6 h, 无溶剂和助催化剂的反应条件下, 碳酸苯乙烯酯的收率和选择性分别为85.5%和95%.

Zr-MOF Hollow Nanospheres Supported Ionic Liquid for CO2 Cycloaddition Reaction

Hollow nanosphere Void@UiO-66-Ⅰ and bulk UiO-66-Ⅰ were designed and prepared by post- synthetic modification（PSM） technique. Such two Zr-MOFs functionalized by quaternary ammonium salt possessed acid-base active sites and hydrogen bond donors. A series of characterization results demonstrated that the two catalysts were successfully synthesized and could be used to catalyze the cycloaddition reaction of CO₂ and styrene oxide. Due to the quaternary ammonium salt of Void@UiO-66-Ⅰ with a large number of hydro-xyl groups and halogen anion， it could induce the epoxide ring-opening by hydrogen bond and nucleophilic attack of the iodide， promoting the reaction proceed smoothly. Moreover， the hollow structure of Void@UiO-66-Ⅰ was conducive to the mass transport. Therefore， it showed better catalytic performance than bulk UiO-66-Ⅰ catalyst for the reaction of CO₂ and styrene oxide cycloaddition. Under optimal reaction conditions（120 ℃， initial CO₂ pressure 1.2 MPa， 6 h）， without solvent and co-catalyst， the yield and selectivity of styrene carbonate（SC） were 85.5% and 95.2%， respectively.