Reactivities and NMR spectra of vinyl ethers

Copolymerizations of n ‐butyl vinyl ether (M 1 ) with other vinyl ethers were carried out in toluene at −78°C with EtAlCl 2 catalyst and the monomer reactivity ratios were determined. It was found that the relative reactivity of alkyl vinyl ether log 1/ r 1 is higher when the alkyl group is more electron‐donating and the reactivity correlates linearly with the Taft σ * of alkyl group in the monomer. The NMR spectra of vinyl ethers and of vinyl ether–trialkylaluminum complexes were investigated. Close correlations were found between the spectral characteristics and the relative reactivity of vinyl ether in the copolymerization. The degree of resonance contribution in alkyl vinyl ether was also discussed on the basis of NMR data.