Comments on a potentially useful new monomer: 4-Vinylbenzylcyclopentadiene

Synthesis of a new vinyl monomer based on cyclopentadiene (CP) has been attempted with the ultimate aim of exploiting the ability of CP to function as both a diene and a dienophile. It was considered that incorporation of the new monomer as a component of a copolymer could, in principle, promote cross-linking by the Diels-Alder (DA) reaction, and breakdown of cross-linking on heating could occur via the retro-DA reaction. This type of reaction is of relevance to the creation of functional polymers such as those needed in flexographic plate development, in the fabrication of novel printable sub-strates and in the formulation of curable coatings. In this work, a solution of sodium-CP was prepared and treated at 0°C under nitrogen with a solution of 4-vinyl benzyl chloride. After removal of the precipitated sodium chloride, the isolated liquid product was analysed by several techniques to disclose the presence of the new monomer 4-vinylbenzylcyclopentadiene (VBCP), its dimer and divinylbenzene-substituted CP. The content of VBCP plus its isomers was approximately 41%. Attempts to effect complete purification were not successful.