Product Yield vs Chain Length in γ-Radiolysis of Normal Saturated Fatty Acids

G-Yields of hydrocarbons resulting from60Co γ-irradiation of normal saturated${\rm C}_{12},\ {\rm C}_{14},\ {\rm C}_{16},\ {\rm C}_{18},\ {\rm C}_{20}$, and${\rm C}_{30}$fatty (carboxylic) acids in the crystalline state (and of the C16and C18acids in the liquid state) have been determined.${\rm G}_{{\rm RH}}$values obtained are in substantial agreement with${\rm G}_{{\rm CO}_{2}}$values recently reported for the same substances (excepting the${\rm C}_{30}$homolog) by Jones (1-3), and his observation that${\rm G}_{{\rm CO}_{2}}$(and hence${\rm G}_{{\rm RH}}$) is, in general, inversely related to chain length is confirmed. Contrary to earlier claim (4), melissic acid (triacontanoic acid, the${\rm C}_{30}$homolog) behaves normally in this regard. Departures from the inverse chain-length relationship are compatible with and may be rationalized by consideration of an additional inverse effect of the density of the irradiated material.