The Reactions of Methyl Radicals. IV. The Abstraction of Hydrogen Atoms from Cyclic Hydrocarbons, Butynes, Amines, Alcohols, Ethers, and Ammonia

The photolysis of acetone in the presence of various compounds has been investigated between 70°C and 340°C. If the reaction $${\mathrm{CH}}_3+{\mathrm{CH}}_3={\mathrm{C}}_2{\mathrm{H}}_6$$ has no activation energy, then the activation energies in kcal for the reactions of the type $${\mathrm{CH}}_3+\mathrm{RH}={\mathrm{CH}}_4+\mathrm{R}$$ are cyclopropane 10.3, cyclobutane 9.3, cyclopentane 8.5, cyclohexane 8.3, benzene 9.2, toluene 8.3, 1‐butyne 9.1, 2‐butyne 8.6, methanol 8.2, ethanol 8.7, iso‐propanol 7.3, methyl ether 9.5, iso‐propyl ether 7.3, monomethyl amine 8.4, dimethyl amine 7.2, trimethyl amine 8.8, and ammonia 10.0. The collision theory steric factors are of the order of 10⁻³ or less for all these reactions. A table is presented summarizing the results so far obtained on methyl radical reactions by the photolysis of acetone in the presence of other compounds. The accuracy of the method and some of the general implications of the results are discussed.