Journal of Catalysis, Vol.313, 159-167, 2014
Alternating copolymerization of CO2 and propylene oxide catalyzed by C-2V-porphyrin cobalt: Selectivity control and a kinetic study
Some C-2V, (C-S)-porphyrin cobalt complexes have been devised, synthesized and utilized as efficient catalysts in combination with dimethylaminopyridine for the alternating copolymerization of propylene oxide and carbon dioxide. The C-2V-catalyst [5,15-diphenylporphyrin]cobalt(III) chloride (1d) has demonstrated excellent reactivity and selectivity under optimized conditions. The axial counterions and the substituents of these metalloporphyrins exhibited distinct infection on the catalytic activity and selectivity. Synchronously, preliminary kinetic investigations of this reaction were achieved by using two catalyst systems illustrating the activation energies of copolymerization and coupling reaction, respectively. A competition mechanism between the polymerization and cycloaddition of propylene oxide and CO2 has been carefully proposed according to our experimental results. (C) 2014 Elsevier Inc. All rights reserved.