Effect of electron density on the catalysts for copolymerization of propylene oxide and CO2

Abstract

Copolymerization of propylene oxide and carbon dioxide (CO2) has been studied using different R-salophenCoOBzF5 (OBzF5 = pentaflorobenzoate, R = CH3, H, Cl, Cl2) based catalysts. The central moiety of the catalysts R-salophenCoOBzF5 has been kept the same and effect of the catalyst electron density on the copolymerization reaction has been studied. It has been observed that introduction of an electron withdrawing group (like Cl, Cl2) on the o-phenylenediamine backbone moiety of the catalyst makes it more selective for poly(propylene carbonate) synthesis. On the other hand, introduction of an electron donating group (like CH3) makes the catalyst selective for cyclic carbonate conversion. The effect of different type of co-catalysts has also been investigated using tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, [PPN]+Cl− ([PPN]+ = bis(triphenylphosphine)iminium), DMAP and tetrabutyl ammonium bromide. © 2016, Springer Science+Business Media Dordrecht.