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.