Synthesis and Polymerization of Spiroorthoesters

Vacuum sublimation (0.01 mm Hg) gives a product with an m.p. 137-141 °C (purity was not determined). 

9-Dimethylene-l,5,7,ll-tetraoxaspiro 5.5 undecane is a spiroorthocarbonate containing two double bonds. It may be prepared starting from cyclopentadiene and acrolein with 40 % yield54). 

The monomer obtained in 86 % yield after purification by recrystallization from hexane and sublimation, melted at 61-62 °C. 

Bulk and solution (methylene chloride, benzene) polymerization with BF3 OEt2 or SnCl4 initiators at 25 °C gave after 48 hrs 70-90 % conversion to polymer with an intrisic viscosity of 0.09-0.12 dl/g (CHClj, 25 °C)9). 

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