Influence of the Molecular Environment on the Three-Center versus Four-Center Elimination of HBr from Vinyl Bromide: A Theoretical Approach

Abstract

The dynamics of dissociative reactions of vinyl bromide was investigated by Langevin molecular dynamics method in the absence and in the presence of frictional interaction between the molecule and its environment. The results show a redistribution of the vibrational energy on the bonds of vinyl bromide under the effect of frictional interaction. This redistribution can modify the reaction rates of vinyl bromide dissociation channels. Increasing the frictional coupling between vinyl bromide and its environment, the vibrational energy redistribution increases the transition probability on the four-center HBr elimination channel. This environment-induced change on the rate of reaction pathways demonstrates that the existence of friction may not guarantee statistical behavior of the dissociation processes of vinyl bromide.

Solvent Switched Weak Interaction of a 4-Quinazolinone with a Cavitand Derivative

“…In our previous studies we found several cases when the kinetic energy shows inhomogeneous and temperature-dependent distribution on the molecules, which is raised by the solute-solvent interactions [8,9].…”

Facile Preparation of BaClxFy for the Catalytic Dehydrochlorination of 1-Chloro-1,1-Difluoroethane to Vinylidene Fluoride

“…Consistent with XRD and TEM results, the XPS spectra of spent catalysts confirm the formation of BaClF during the catalytic pyrolysis of HCFC-142b ( Figure S5). In addition to the composition of catalysts, reaction temperature [40], reaction pressure and environment [41] play an important role in the catalytic performance of the pyrolysis process. These issues will be addressed in the future studies after the optimization of the catalysts.…”

Unexpected reactivity difference between iodo-alkene moieties of steroids possessing remote lactame or cycloalkane structural units: a theoretical approach

“…Our recent examinations regarding some special reactions of vinyl bromide [17] and of the whole vinyl-halogenid serie [18] pointed out the decisive role of vibrational energy distribution and induced redistribution on the dissociation reaction rate. Therefore, the methodology described there [17,18] was followed to examine the backgrounds of the unexpected reactivity difference of 1, 2 and 3 predicted by the experiments.…”

“…Therefore, the methodology described there [17,18] was followed to examine the backgrounds of the unexpected reactivity difference of 1, 2 and 3 predicted by the experiments.…”

“…This is accomplished by adding a random force (to model the effect of collisions) and a frictional force (to model dissipative losses) to each atom at each time step during the simulation. Application of this method for the investigation of the C-X (X=F, Cl, Br, I) bond-breaking of halo-ethene was described elsewhere recently [17,18]. The results of the Langevin dynamic calculations show the decrease of vibrational energy localized on the idodovinyl site (reduced to 12% and 9% in case of 2 and 3, respectively).…”