The Reactions of Methyl Radicals with the Hydrogen Isotopes

Abstract

The photolysis of acetone has been studied in the temperature range 130–420°C. Measurements have been made of the rates of most of the possible reactions of CH3 and CD3 radicals with hydrogen, deuterium, and deuterium hydride. The following activation energies for the abstraction of a hydrogen or deuterium atom have been found: CH3+acetone, 9.7; CD3+d acetone, 11.6; CH3+D2, 11.8; CD3+H2, 11.1; CH3+HD→CH4, 10.0; CH3+HD→CH3D, 11.3; CD3+HD→CD3H, 10.7; CD3+HD→CD4, 10.7 kcal. The steric factors are all of the order of 10−3. The results are discussed in terms of isotope effects with particular reference to the deuterium hydride reactions.