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The polymerization of isobutyl vinyl ether by trifluoroacetic acid

1980; Wiley; Volume: 181; Issue: 4 Linguagem: Inglês

10.1002/macp.1980.021810407

0025-116X

Frederick Bolza, F. E. Treloar,

Chemical Reactions and Mechanisms

Abstract The polymerization of isobutyl vinyl ether (IBVE) initiated by trifluoroacetic acid (TFA) in 1,2‐dichloroethane and in 1,2‐dichloroethane/carbon tetrachloride mixtures has been studied over the temperature range −2,5°C to 35°C. Provided that the ratio [IBVE]/[TFA] did not exceed 88 and that 2·10 −4 mol·1 −1 < [TFA] < 4·10 −3 mol·1 −1 polymerization was the only detectable reaction, and the initial rate of reaction R 0 was equal to k [IBVE] 2 [TFA]. The activation energy of the rate = (34 ± 2) kJ · mol −1 and the activation energy of the molecular weight = − (11,9 ± 0,5) kJ · mol −1 . When [TFA] < 1·10 −4 mol/l, no reaction was detectable. The polymers produced had molecular weights less than 4400; the only transfer is by monomer and this is the main chain‐breaking step. The reaction was unaffected by the addition of water for [H 2 O] < [TFA]. The rate depended on the solvent dielectric constant, but in a manner suggestive of a dipole‐dipole reaction. A mechanism is proposed for the reaction in which the reactive intermediates are trifluoroacetate esters solvated by monomer.