Study On The Synthesis Of Chiral Salen Mn (Ⅲ) Immobilized Onto Aminated Zirconium Phosphonate By Axial Coordination And Catalytic Asymmetric Epoxidation Of Olefins

In recent years, the heterogeneous asymmetric catalysis has received considerable attention in the field of catalysis. The suitable type of catalyst support for chiral ligand is the key importance for obtaining the high catalytic properties in the heterogeneous asymmetric catalysis. In this paper, chiral Salen Mn (Ⅲ) complex was successfully immobilized onto the aminated zirconium phosphonate by axial coordination with different linkage arm lengths.In the paper, chiral Salen Mn (Ⅲ) immobilized onto aminated zirconium phosphonate by axial coordination including 5a～e had been synthesised. The structure and morphorlogy of these catalysts had been characterized by using FT-IR, TG, N2-sorption, AAS, and the mount of chiral Salen Mn(Ⅲ) complex had been determined.In the catalytic reaction of the asymmitric epoxidation of unfunctionalized olefins, the NaClO and m-CPBA were used as oxidants for asymmetric epoxidation of styrene,α-methylstyrene and indene respectively. It was noted that the supported chiral Salen Mn (Ⅲ) such as 5e, which was immobilized onto aminated zirconium phosphonate by axial coordination, gave the higher catalytic properties (conversions 98.8% and 79.5%e.e.) than the corresponding homogeneous Mn (Ⅲ) Salen complex in the asymmetric epoxidation of a-methylstyrene. After the reuse five times, and the supported chiral Salen Mn (Ⅲ) 5e could also give the conversions 63.5% and 51.4% e.e., which was also higher than the corresponding homogeneous catalyst.