Terrestrial heat flow in Great Britain

In the kinetics of their gas phase oxidations primary and some secondary chloro-paraffins are generally similar to the corresponding hydrocarbons. The rate is strongly affected by the pressure of the organic reactant and nearly independent of oxygen. (With tertiary chlorocompounds an oxygen-catalyzed pyrolysis obscures the direct oxidation.) For the oxidation a mechanism analogous to that proposed for hydrocarbons is assumed, namely one in which the rate is governed by branching chains whose development depends upon the breaking of an unstable $\chembond{1,0} $O$\chembond{1,0} $O$\chembond{1,0} $ link. Previous work on the influence of hydrocarbon structure is interpreted with the aid of the hypothesis that methyl groups exert a specific stabilizing effect (and that relatively rapid oxidation demands a point of attack in the molecule sufficiently remote from a methyl group). In the light of this hypothesis the influence of chlorine atoms is compared with that of methyl groups. The chlorine accelerates the oxidation (a) by impairing the symmetry of a methyl group into which it is introduced, and (b) by a direct inductive effect of its own. The opposite effects of chlorine and of methyl are consistent with the view that the $\chembond{1,0} $O$\chembond{1,0} $O$\chembond{1,0} $ links are stabilized by electron accession and weakened by electron recession.