Halogenated meso-phenyl Mn(III) porphyrins as highly efficient catalysts for the synthesis of polycarbonates and cyclic carbonates using carbon dioxide and epoxides

Identifier:  PC:2700

Handle: https://hdl.handle.net/20.500.11797/PC2700

Authors:  Cuesta-Aluja, L.; Castilla, J.; Masdeu-Bultó, A.M.; Henriques, C.A.; Calvete, M.J.F.; Pereira, M.M.

Abstract:
Introduction of halogen electron withdrawing atoms (chloro and fluoro) in the ortho position of the aryl groups of meso-tetraphenylporphyrin manganese(III) complexes increased their activity as catalysts in the reaction of carbon dioxide with epoxides, when compared with the meso-tetraphenylporphyrin manganese(III) counterpart, even in the absence of co-catalysts. In the polymerization reaction of carbon dioxide and cyclohexene oxide, almost ten-fold increase of the TOF was observed when 5,10,15,20-tetra(2,6-dichlorophenyl)porphyrinatomanganese(III) acetate or 5,10,15,20-tetra(2,6 difluorophenyl)porphyrinatomanganese(III) acetate complexes were used as catalysts. Under similar conditions, when terminal epoxides were used as substrates, the selective cycloaddition of CO2 with styrene oxide, epichlorohydrin, propylene oxide, and 1,2-epoxytetradecane yielded exclusively the corresponding cyclic carbonates (conversion 54-98 %).