Synthesis of Cyclic Carbonates from CO2 and Epoxide Catalyzed by Co, Ni and Cu Complexes in Ionic Liquids

A series of first row metal complexes (Co, Ni and Cu) containing commercial nitrogen ligands were synthetized and used as catalyst in the cycloaddition of CO2 to epoxides. The reaction was carried out in ionic liquids based on 1-n-butyl-3-methylimidazolium as solvents. Best catalytic results were achieved with Co catalysts in 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIm.BF4). Under optimized reaction conditions cyclic carbonates were selectively obtained with good to excellent yields, presenting a reliable alternative to synthetize the product using low cost and abundant catalytic system containing a common ligand as ethylenediamine. Finally, macrocycle effects where studied in each case comparing the conversion rates obtained by using ethylenediamine and 1,4,8,11-tetraazacyclotetradecane.