A Study of the Solvent Effect in the Copolymerization of N-Phenylethylenimine with β-Propiolactone

Abstract

Abstract The effect of the solvent on the copolymerization of N-phenylethylenimine with β-propiolactone has been studied quantitatively. The copolymerization rates for the various solvents used increase in the order: diethyl ether > toluene < carbon tetrachloride < methyl acetate < N,N-dimethylacetamide < anisole < dioxane < acetone < ethylene dichloride < acetonitrile < acetophenone < nitrobenzene < dimethyl sulfoxide < nitroethane. The rates in solvents with high dielectric constants are much larger than those in solvents with low dielectric constants. However, in the case of solvents with similar dielectric constants, the rates decrease with an increase in the nucleophilicity of the solvent; moreover, the dependency of the copolymerization rate on the nucleophilicity of the solvents is much larger in the solvents with high dielectric constants than in those with low dielectric constants. The rate of the consumption of N-phenylethylenimine is markedly affected by the nucleophilicity of the solvents in solvents with high dielectric constants, but it is little affected in solvents with low dielectric constants. Although there is no effect of the nucleophilicity of the solvents on the consumption rate of β-propiolactone, the rate of the consumption of β-propiolactone varies with the electrophilicity of the solvent in solvents with high dielectric constants. On the other hand, the β-propiolactone content in the copolymer increases in proportion to the nucleophilicity of the solvents with high dielectric constants, whereas the β-propiolactone content in solvents with low dielectric constants is almost constant regardless of the electric nature of the solvents.