Inhibition of cumene oxidation by polyarylenes

Abstract

AbstractThe kinetics of the initiated cumene oxidation at 60°C in the presence of polyarylenes (polyanthracene (PA), polynaphthalene (PN), copolymers of benzene with anthracene (AB), and naphthalene (NB) has been investigated. The initial oxidation rate dependence upon the initial concentration of inhibitor has been described by the equation obtained for inhibition mechanism which defines the radical attaching to a molecule of inhibitor as the rate limiting step of the reaction, rather than the reversible complex formation. Radical reactivity of polyarylenes increases in the order NB < PN < PA < AB, that is, it is consistent with the increase of reactivity of repeating units of polymer molecules. Reactivity of PA (calculated per repeating unit) is unaffected by the increase of molecular weight. The total quantity of radicals consumed by one molecule of inhibitor is calculated to be equal to 0.29; 1.4; 7.6 and 11 for NB, PN, PA, and AB, respectively. The most active centers in the reaction of inhibition are shown to be paramagnetic centers. Conjugation degree in polyarylene molecules diminishes during the course of the reaction. The main products of PA transformation are PA molecules having 1,4‐anthraquinone units.