A series of 2-azido-4'-R-azobenzenes has been prepared and the rate of their thermal decomposition to give 2-(4-R-pheny1) benzotriazoles has been determined in anisole. The effect of substituents was small, showing a slight acceleration by electron withdrawing groups. The reaction exhibited an isokinetic region at 77 f 20" C. In several cases, rates were observed on each side of the isokinetic temperature. The enthalpy of activation varied ...
