The thermal reactions of ethylene at 500°C in the presence and absence of small quantities of oxygen

Initial rates of formation of primary products have been measured in the pyrolysis of ethylene at 500°C, and a mechanism for the reaction is proposed based on the isomerization of the n−hexyl radical. Additions of oxygen in amounts less than 0.1% markedly increased the rate of formation of all products, but oxygen was not completely consumed in the reaction. It is shown that secondary initiation processes are important at very low conversions, and butene‐1 is the most reactive product. Bimolecular reactions between olefins and with oxygen are important steps in the mechanism.