Cyclocopolymerization of diallyl ether with sulfur dioxide in acetone

The radical polymerization of diallyl ether (DAE) with sulfur dioxide produced soluble copolymers whose composition was between 1:1 and 2:1 in SO₂. The overall rate was maximum at a 2:1 feed composition in SO₂. A cyclocopolymerization scheme, which was based on cross propagations and the intramolecular cyclization of DAE radical, was applied. The energy of activation was larger for the uncyclized DAE radical in undergoing the cross propagation with SO₂ than in undergoing the intramolecular cyclization with the pendent allylic group by 40 kJ/mol. Formation of rings made of DAE and SO₂ and 3,4-disubstituted-tetrahydrofuran rings by the cyclized DAE units on the main chain was proposed on the basis of the ¹H-NMR spectra.