Hydroxyl Functionalized Methacrylic Terpolymers as Supports for Mn(Ⅲ) Salen Catalysts and Their Application in Asymmetric Epoxidation

摘要

Hydroxyl functionalized gel type resins derived from 2-hydroxyethyl, 2-hydroxypropyl and 2-hydroxy-3-phenoxypropyl methacrylates were applied to covalent immobilization of Mn(salen) complexes via glutarate and carbonate linkers. The obtained catalysts were characterized by FTIR and DR UV-Vis methods and elemental analysis. It was found that the activity of polymeric catalysts obtained in this way depended on both the nature of the functional and cross-linking monomers and the degree of the cross-linking of polymer matrices and the way of complex immobilization. The highest activity was observed for the complexes immobilized on the HEMA resins cross-linked with 3%-mol of diethylene glycol dimethacrylate. For instance, in the presence of the catalysts with (S,S)-salen ligand S-epoxystyrene and (IS, 2R)-epoxyindene could be obtained with 46% and 69% ee, respectively. Attempts have also been made to recycle the selected catalyst. However, a rapid fall off in the activity was observed, although the selectivity was similar in which three cycles.