Abstract:

Chiral Salen Mn(III) complex axial coordination immobilized on diamine or ployamines modified Zirconium poly (styrene-isopropenyl phosphonate)-phosphate(ZPS-IPPA),were prepared by a covalent grafting method. All the supported heterogeneous chiral Salen Mn(III) complexes prepared were characterized by FT-IR,diffusion reflection UV–vis,XPS,SEM,TEM and TG. The supported catalyst was applied to the enantioselective epoxidation of a-methylstyrene using NaClO and m-CPBA as oxidants. The result s confirmed that the activity of the supported catalyst was lower than that of the homogeneous chiral Salen Mn ( Ⅲ) . However,it s enantioselectivity was higher than that of the homogeneous one. A conversion of 68 % and ee of 99% of epoxide were obtained when a-methylstyrene was oxidized by NaClO for 24 h at 20 ℃ in the presence of the 4-PPNO. The catalysts were easily recovered by filtration and could be reused at least eight times with little loss of activity and enantioselectivity.

Key words: Zirconium poly (styrene-isopropenyl phosphonate)-phosphate, chiral Salen Mn ( Ⅲ), axial coordination supported catalyst, asymmetric epoxidation, a-methylstyrene