2-Methylene-4-phenyl-1,3-dioxolane(I) was prepared as before. The radical copolymerization of I with acrylonitrile was performed in benzene with AIBN at 60℃ The copolymer obtained revealed that I was copolymerized with acrylonitrile with only small extent (6.8%) of ring opening. Most of I was incorporated into the copolymer via conventional vinyl polymerization mode, exhibiting also the tendency to alternate. The copolymer composition was 49.6% I to 50.4% acrylonitrile.
The copolymerization of I with ethyl α-cyanoacrylate (ECA) gave complicated mixtures of products. This complication was found to be caused by the adduct formation between I and ECA. This adduct, which was identified to be 2-phenyl-7-ethoxy-8-cyano-1,4,6-trioxaspiro [4,5] dec-7-ene(II), was formed in high yield at -20℃ but isomerized to the more stable IV at room temperature. Methanol could open the cyclic ortho ester I giving another ortho ester V.
The adduct II did not polymerize radically but polymerized well with cationic initiators such as $BF_3$ at -30℃ giving soluble polymer (III). Spectral data showed that polymer III is a head-to-head alternating copolymer of I and ECA having I copolymerized without ring opening.
