Immobilization of Chiral Mn III (Salen) on Phenoxyl Group Modified Zirconium Poly (Styrene-Isopropenyl Phosphonate)-Phosphate and Catalytic Performance for Epoxidation of Styrene

A series of chiral Mn Ⅲ (Salen) catalysts that were axially supported onto zirconium poly (styrene-isopropenyl phosphonate)-phosphate(ZPS-IPPA) through phenoxyl linkers have been developed, and their performance as catalysts for the epoxidation of styrene has been evaluated. The catalytic results indicated that the substituents at the o -positions of the phenoxyl linkers have a critical impact on the catalytic activity, in that the o - t -Bu group provided higher levels of enantioselectivity than the o -H and o -CH 3 groups of the phenoxyl linker. At the same time, two linkages (-NH-C 6 H 4 -NH-, -O-C 6 H 4 -O-) with similar length were compared, the results demonstrated that the linkage of -O-C 6 H 4 -O- have more positive effect than the use of -NH-C 6 H 4 -NH-in absence of NMO in m -CPBA oxidant systems on the catalytic efficiency. Furthermore, the catalysts could be recycled up to five times without any significant reduction in their catalytic activity or enantioselectivity.