Polymerization of 2-vinyl-1,3-dioxolane

When 2-vinyl-1,3-dioxolane was treated at low temperature (?78 or ?130°C.) with cationic catalysts, oily or semi-solid polymer was produced. The result of alkaline hydrolysis showed that the polymeric product contained ester units whose amount was about 2 to 15 mole-% of the total units. The remaining part of the polymer consisted of units containing the dioxolane ring. In the alkaline alcoholysis of the polymer with ethanol ethyl δ-hydroxyvalerate was formed. These findings indicate that in the low temperature cationic polymerization of 2-vinyl-1,3-dioxolane the ester unit, ? O(CH₂)₄CO? , is formed in addition to the unit of vinyl polymerization. A mechanism for the formation of the ester unit has been proposed, in which the process of hydride-shift is followed by ring-opening of the resulting carbonium ion species of dioxolane.