Displacement Reaction Dynamics of Fluorine Atoms with Vinyl Bromide Molecules

Article abstract of DOI:10.1021/j100066a017

Reactive scattering of F atoms with C2H3Br molecules leading to both H and Br atom displacement has been studied at an initial translational energy E ca. 40 kJ mol^-1 using a supersonic beam of F atoms seeded in He buffer gas.The center-of-mass angular distribution of C2H3F reactive scattering shows a sharp forward peak with a lower backward peak of relative intensity ca. 0.5.The product translational energy distribution peaks at a low fraction f'_pk ca. 0.1 of the total available energy with a tail extending up to higher energy.The branching ratio ca. 10 strongly favors Br atom displacement.The H atom displacement pathway occurs in competition with F atom migration in the FCH2CHBr^. radical formed by F atom addition to the C=C double bond.The Br atom displacement occurs in the ^.CH2CHBrF radical formed either by F atom migration from FCH2CHBr^. or directly from F atom addition to the C=C double bond.In either case, Br atom displacement occurs rapidly compared with the rate of F atom migration over the potential energy barrier in the bridged configuration, resulting overall in a short-lived collision complex mechanism for the formation of C2H3F reaction products.