Microstructure of copolymer and catalyst species in the copolymerization of 3,3‐bis (chloromethyl) oxacyclobutane and β‐propiolactone with boron trifluoride etherate

In the studies of the BF3·Et2O catalyst copolymerization of 3,3‐bis(chlormethyl)oxacyclobutane and β‐propiolactone, there have been obtained several observations suggesting that a reaction between the BF3·Et2O catalyst and the monomers occurs in the course of copolymerization to produce different catalyst species, which also induce copolymerizations of different character. Consequently there exist at least two kinds of catalyst species in this copolymerization system. Therefore, the copolymerization parameters obtained by a conventional technique are merely apparent and are not reasonably referred to in the quantitative discussion of monomer reactivity and of monomer unit distribution in the produced copolymer. The (deviation of the monomer unit distribution from the one calculated by statistical treatment has been ascribed to the multiplicity of catalyst species.)