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.