Preparation of Schiff base metal catalyst and its catalytic synthesis of propylene carbonate from CO2

Abstract

In recent years, research on the conversion of CO2 into fine chemical products has emerged as a prominent and dynamic area of study. In this study, four ligands were synthesized using salicylaldehyde, o-phenylenediamine, ethylenediamine, hexanediamine, and 2,6-diaminopyridine as precursors. Subsequently, these ligands were reacted with cobalt nitrate, zinc chloride, and aluminum chloride to synthesize 12 Schiff base metal complexes, which were employed as catalysts for the synthesis of propylene carbonate from CO2 and epichlorohydrin. The findings reveal that the SF-L/Co catalyst demonstrated superior performance, potentially attributed to the robust chelating capability of Co, leading to the provision of more acidic metal centers. Characterization of SF-L/Co was conducted utilizing scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) techniques. Process conditions were optimized, resulting in the achievement of a 100% yield and selectivity of propylene carbonate under optimal reaction conditions, without the generation of any by-products. Furthermore, the catalyst exhibited remarkable reusability, demonstrating consistent catalytic activity over five successive cycles without a substantial decrease in performance.