Syntheses of cyclic carbonates from carbon dioxide and epoxides with metal phthalocyanines as catalyst

Various cyclic carbonates from epoxides and carbon dioxide were prepared with the binary catalytic systems of aluminum phthalocyanine (PcAlCl) and base cocatalysts, such as tributylamine, 1-methylimidazole and triphenylphosphine. Under employed conditions, cyclic carbonates were produced nearly quantitatively from CO2 and the corresponding epoxides. The reaction appeared to be temperature dependent and was affected by the amount of base cocatalyst in the binary catalytic systems. The catalyst was not overly sensitive to air and water and could be subjected to utilization for several recycles without the obvious loss of activity. In contrast to PcAlCl, other divalent metal phthalocyanines (MtPc) used did not show high catalytic activities towards the reaction. Their activities were in the order: PcAlCl>MgPc>FePc>>NiPc or CoPc. Some plausible mechanisms are also discussed. (C) 2000 Elsevier Science B.V. All rights reserved.