We study the nonequilibrium effects in an adiabatic system with thermally activated reactions
A+AB+BC+C. The results of a simple phenomenological theory which assumes that temperatures of reagents may be different from the temperature of the system as a whole are compared with results of molecular dynamics simulations. We show that the nonequilibrium effects caused by one reaction may be magnified as well as reduced by the presence of the other processes. Good agreement between theory and simulations has been obtained.