Mechanisms of the thermal decay of chlorpropham

► Chlorpropham is predicted to be unstable under the conditions of its application. ► Decomposition of chlorpropham is predicted to occur via ester pyrolysis. ► Experimental data indicate that ester pyrolysis takes place at T > 500 °C. ► At lower temperature, chlorpropham is found to decay into m-chlorophenylisocyanate. ► Highly toxic m-chloroaniline is the final product of chlorpropham decomposition.