Non-halogen catalysts for propylene carbonate synthesis from CO2 under supercritical conditions

Cesium–phosphorous–silicon mixed oxide (Cs–P–Si oxide), a typical acid–base bifunctional catalyst, efficiently catalyzes propylene carbonate synthesis from CO2 and propylene oxide under supercritical conditions (8–10 MPa). This catalyst contains no halogens and requires no additional solvents. A portion of the catalyst was eluted into the product solution during catalysis. It was also found that Cs3PO4, one of the species that may be eluted from the Cs–P–Si oxide, is an effective non-halogen homogeneous catalyst.