Determination of absolute rate constants for olefinic oxidations by measurement of photochemical pre- and after-effects. Part I. - At "high" oxygen pressures

Abstract

Photochemical pre- and after-effects arising from the free radical chain character of olefinic oxidations are analyzed theoretically and simple expressions permitting the propagation and termination rate constants to be separately evaluated are derived. In practice, the theoretical equations are modified by important experimental correcting terms; these are discussed and a method of obtaining the required ratio of the constants without evaluating the corrections is described. The values of the constants for dihydromyrcene and ethyl linoleate thus obtained agree closely with those determined via the rotating sector technique. In addition, we have now examined oct-1-ene, digeranyl, gutta-percha and rubber, and the relevant results, together with our earlier results (for eight olefins in all) are summarized, and attention directed towards certain notable features.