Schiff base Cu(II) complexes as catalysts in the transformation of CO2 to cyclic carbonates at both high and atmospheric pressure

A stable and readily synthesized catalyst system from Schiff base Cu(II) complexes was developed for the efficient transformation of CO2 and oxiranes to cyclic carbonates. After seeing the high catalytic conversion of different forms of the synthesized Schiff base Cu(II) complexes, the effect of epoxide, base, temperature, CO2 pressure, and reaction time were investigated for these catalysts. Also, the reaction was carried out both at high pressure and atmospheric pressure. The Schiff base Cu(II) complex (2) showed high catalytic activity (at 100 °C and 1 atm of CO2 pressure) for the carboxylation of epichlorohydrin at atmospheric ambient. The Schiff base Cu(II) complex would even be carried out under atmospheric pressure, giving carbonates in good yield. The best conversion in atmospheric ambient was performed in the presence of 2 catalyst and DMAP as co-catalyst, with a %99.2 yield and %99.6 selectivity at 100 °C, 6 h, and 1 atm of CO2 pressure.