Efficient pathway for CO2 transformation to cyclic carbonates by heterogeneous Cu and Zn salen complexes

A series of silica supported Salen type Zn(II) and Cu(II) complexes were prepared and characterized. The obtained materials were characterized by X-ray diffraction (XRD), sorption measurement (BET), Fourier transform infrared spectroscopy (FT-IR), atomic absorption spectroscopy (AAS), atomic force microscopy (AFM), scanning electron micrograph (SEM), thermal and elemental analysis. The chemical fixation of CO2 to form cyclic carbonates in the presence of a Lewis base was efficiently performed by this heterogeneous catalyst system. Very high yield and conversions were obtained at 1.0 MPa CO2 atmosphere without an addition of any solvent. The active heterogeneous Cu-DTBSA was efficiently transformed CO2 into cyclic carbonates while the reusability of the Cu-DTBSA is eight times with minimal decrease in yield.