Kinetics of Decomposition of the 1-Methyl-1-nitroso-3-phenylurea Derivatives

Abstract

The kinetics of decomposition of the 3-substituted-phenyl-1-nitroso-1-methylureas was studied under a certain pH and various temperatures. It was observed that the rate of decomposition is first order in concentration of the nitroso compound under the constant pH and that the more the electron withdrawal of the ring substituent, the larger is the rate of decomposition. From the temperature dependence of the rate, the apparent enthalpy and entropy of activation were determined. The sequence of the rate of decomposition of this series of compounds was found to be governed largely by the variation of the entropy rather than that of the enthalpy of activation.