Polyoxometalate as co-catalyst of tetrabutylammonium bromide in polyethylene glycol (PEG) for coupling reaction of CO2 and propylene oxide or ethylene oxide

The coupling reaction of CO2 and propylene oxide or ethylene oxide to produce corresponding cyclic carbonate in the presence of a catalytic system composed of n-Bu4NBr, α2-(n-Bu4N)9P2W17O61(Co2+ · Br) (abbreviated as P2W17Co) and PEG (MW 400) has been investigated. The experimental results indicated that the synthesis of propylene carbonate (PC) or ethylene carbonate (EC) achieved with over 98% yield and 100% selectivity within 1 h at 120 °C by using the above catalyst system. When the catalyst system was recycled, the catalytic activity slowly diminished. Moreover, a plausible mechanism was proposed.