A highly active catalytic system for CO2/(propylene oxide) copolymerization was prepared based on the concept of a system containing a Lewis acidic metal center and quarternary ammonium salts units. The catalytic system showed high activity (TON >20000; TOF >20000 h-1) even at high temperature and high [epoxide]/[catalyst] ratio and selectively producing a very high molecular-weight copolymer (Mn, 300,000). The catalyst can be easily separated by filtration through a short pad of silica gel to obtain polymer containing negligible amounts of metal residue (1-2 ppm). The separated catalyst can be reused without significant loss in catalytic performance.
