The Reactions of Ethyl Radicals

Abstract

The photochemical investigation of the decompositions of diethyl zinc and diethyl mercury has established that the products in each case consist principally of ethane, ethylene, and butane, with smaller amounts of hydrogen and butylene. The composition of the product varies with the alkyl, but does not change markedly with temperature from 45° to 250°. An examination of the effects of varying the concentration, intensity of radiation, packing of reaction vessel, and inert gas pressure leads to the conclusion that butane is formed by the combination of two ethyl radicals produced in the primary process, while ethane and ethylene arise from a reaction between ethyl radicals and metal alkyl molecules. The reaction between ethyl radicals and hydrogen becomes measurable at about 160°, and by analogy with the corresponding process with methyl radicals may be assigned an activation energy of 9±2 kcal. The reaction C₂H₅+H=2CH₃ proceeds rapidly at 100°. The investigation of the photolysis of ethyl iodide in the presence of mercury vapor and the mercury photosensitized hydrogenation of ethylene supports the conclusions based on the metal alkyl studies.