Cycloaddition of carbon dioxide to propylene oxide catalysed by tetra-t-butylphthalocyaninatoaluminium(III) chloride

Cyclic propylene carbonate was obtained from propylene oxide in the presence of 1-methylimidazole with atmospheric carbon dioxide at room temperature using tetra-t-butylphthalocyaninatoaluminium (III) chloride as catalyst. The reaction proceeded via insertion of propylene oxide and carbon dioxide between the aluminium(III) ion and the axial ligand. Coordination of the base such as 1-methylimidazole to the aluminium(III) weakens the bonding between the aluminium(III) and the axial ligand, promoting the insertion of carbon dioxide.