Kinetics of the Decomposition of α-Phenylethyl Hydroperoxide in the Presence of N,N,N′,N′-Tetramethyl-para-Phenylenediamine

Abstract

It is found that the tertiary amine N,N,N′,N′-tetramethyl-para-phenylenediamine (TMPD) causes the decomposition of α-phenylethyl hydroperoxide (ROOH), and the interaction between the components occurs in accordance with a complicated rate law. It is demonstrated that more than 30 hydroperoxide molecules (n) can be degraded at a molecule of TMPD; this fact suggests that the amine has a catalytic effect on the process. The value of n increases with the [ROOH]0/[TMPD]0 ratio. The initial rates of consumption of ROOH and TMPD linearly increase with the initial concentrations of both of the reactants. The apparent rate constant of the reaction is k = 0.4 l mol−1 s−1 (393 K), as calculated from the initial rates of ROOH consumption. As a result of the interaction, TMPD is converted into an inhibitor. The rate constant of the reaction of this inhibitor with ethylbenzene peroxy radicals is about 2 × 104 l mol−1 s−1.