Efficient Solvent-free Synthesis of Chloropropene Carbonate from the Coupling Reaction of CO2 and Epichlorohydrin Catalyzed by Magnesium Porphyrins as Chlorophyll-like Catalysts

Highly efficient solvent-free coupling reaction of carbon dioxide (CO2) and epichlorohydrin catalyzed by meso-tetraphenyl porphyrin magnesium (MgTPP) in the presence of triethylamine as co-catalysts is reported. As a chlorophyll-like catalyst, MgTPP showed excellent activity for the coupling reaction of CO2 and epichlorohydrin to chloropropene carbonate, in which the turnover number could reach up to 9200. Moreover, different factors including the amount of catalyst, reaction temperature, pressure and time were systematically investigated and the optimal reaction conditions were obtained (epichlorohydrin 50 mmol, MgTPP 5.0×10−3 mmol, triethylamine 6.25(10−3 mmol, 140 °C, 1.5 MPa, 8 h). A plausible two-pathway mechanism for the coupling reaction of CO2 and epichlorohydrin is proposed to propound the catalysis of MgTPP.