Studies of radiation-induced reactions of ethylene in aqueous solution I. Reactions in the absence of oxygen

Abstract

Studies have been made of the effect of 60 Co y-radiation on dilute aqueous solutions of ethylene. The influence on the products of dose, ethylene pressure, pH of the solution and additives has been systematically investigated. In neutral and acid solutions of pure ethylene, polymerization is the main process, although small amounts of hydrogen peroxide and C 2 —C 4 aldehydes are formed simultaneously. Formation of polymer is largely inhibited in the presence of added Fe 3+ ions or hydrogen peroxide. The velocity constant ( k ) for the reaction of the solvated electron with ethylene has been determined directly by a pulse radiolysis technique and this reaction has been shown to proceed slowly if at all ( k < 2.5 x 10 6 1. mole -1 s -1 ). It may, therefore, not be involved to any appreciable extent in the radiolysis of ethylene. The results obtained enable deductions to be made as to the principal elementary stages involved in the reaction. It is shown that hydrogen atoms and hydroxyl radicals are the main species which initially attack ethylene and that vinyl, ethyl and β -hydroxyethyl radicals all probably play an important part as intermediates in the reaction mechanism.