胺化聚(苯乙烯-异丙烯膦酸)-磷酸氢锆轴向负载手性salen Mn(Ⅲ)的制备及其对α-甲基苯乙烯不对称环氧化反应的催化

Preparation of Aminated ZPS-IPPA Axial Coordinated Chiral Salen Mn(Ⅲ) and its Catalysis for α-Methylstyrene Asymmetric Epoxidation Reaction

以聚(苯乙烯-异丙烯膦酸)-磷酸氢锆(ZPS-IPPA)为载体,通过对载体进行氯甲基化、胺化修饰后与手性Salen Mn(Ⅲ)轴向配位,合成了一种新的固载型手性Salen Mn(Ⅲ)催化剂。采用FTIR、DRUV-Vis、XPS、SEM、TEM等测试技术对催化剂进行表征。以次氯酸钠和间氯过氧苯甲酸为氧化剂,考察了固载催化剂对α-甲基苯乙烯不对称环氧化反应的催化性能。结果表明,固载型催化剂的催化活性比相应均相催化剂略低,但对映体选择性明显提高。在NaClO/PPNO氧化剂体系中0℃反应24h,α-甲基苯乙烯环氧化反应的转化率达68%,对映选择性e.e.值达99%,循环使用8次后催化效果无明显降低。

Chiral Salen Mn（Ⅲ） complex was axially coordinated on diamine or polyamines modified Zirconi- um poly （styrene-isopropenyl phosphonate）-phosphates （ZPS-IPPA） by a covalent grafting method. All the supported heterogeneous chiral Salen Mn （Ⅲ） complexes prepared were characterized by FF-IR, diffusion reflection UV-Vis, XPS, SEM and TEM. The supported catalyst was applied to the enantioselective epoxidation of α-methylstyrene with NaC10 and m-CPBA as oxidants. The results confirm that the activity of the supported catalyst was lower than that of the homogeneous chiral Salen Mn （Ⅲ）. However, its enantioselectivity was higher than that of the homogeneous one. A conversion of 68% and an e. e. of 99% of epoxide were obtained when α-methylstyrene was oxidized by NaCIO for 24 h at 0℃ in the presence of 4-PPNO. The catalysts were easily recovered by filtration and could be reused for at least eight times with little loss of activity and enantioselectivity.