Abstract: Y(acae)₃-H₂O-Al(i-Bu)₃ was used for homopolymerization of epichlorohydrin(ECH) and copolymerization of ECH with propylene oxide(PO) or ethylene oxide(EO). The molecular weight distribution of PECH determined by GPC showed that the number of the active species in the catalyst depends on the method of catalyst preparation. For copolymerization the monomer reactivity ratios obtained by NMR as follows: 2.08/0.21 for PO/ECH, 11.9/0.21 for EO/ECH.

Key words: yttrium acetylacetonate, epichlorohydrin, propylene oxide, ethylene oxide polymerization, copolymerization