Vinyl ether end-groups in poly(ethylene glycol)s from the Na2CO3-promoted degradation of 1,3-dioxolan-2-one polymers

The Na2CO3-promoted polymerization of 1,3-dioxolan-2-one (I) to afford poly (ethylene glycol)III was reinvestigated. The reaction appeared to involve a nucleophilic attack against the carbonyl and methylene groups of I to affo rd poly(carbonate) II with poly(ethylene glycol) Linkages and ethylene oxid e IV as a side product (10-22%). As the reaction progressed, poly(carbonate ) If decreased and poly(ethylene glycol) III increased. Under some conditio ns, poly(ethylene glycol)s V and VI with vinyl ether terminal groups were f ormed unexpectedly. The formation of unsaturated products during the polyme rization of I/EO (ethylene oxide) has not been reported in the literature. We believe that vinyl ethers were formed from the degradation of poly(carbo nate)s and were accompanied by a reduction in molecular weight. The structu res of vinyl ethers V and VI were confirmed by hydrogenation of the double bond into the ethyl ether group in VIT and Vm, respectively. (C) 2000 John Wiley & Sons, Inc.