The pinanes are preferably attacked at the tertiary C‐H bond in 2‐position, but products of the oxidative attack at the secondary C‐H bonds in 3‐ and 4‐position are also found. At 100°C cis‐pinane is attacked more easily than trans‐pinane (kcis : ktrans = 6.4), the relative rates of attack at the secondary C‐H bonds in positions 3 and 4 with respect to the tertiary C‐H bond in 2‐position were also determined (in cis‐pinane ksec: ktert = 0.027; in trans‐pinane ksec : ktert = 0.20). After the attack at the 2‐C‐H bond the radical formed can either react with oxygen to form the corresponding cis‐ and trans‐peroxy radicals and further to give cis‐ and trans‐2‐hydroperoxy pinane or fragmentate to the monocyclic radical derived from α‐terpinene, giving as final products α‐terpinene hydroperoxide and the bicyclic 8‐hydroperoxy 4,4,8‐trimethyl 2,3‐dioxabicyclo[3.3.1]nonane. The corresponding alcohols were found after reduction with sodium sulphite. The oxidation at position 2 of the pinanes delivers not only the cis‐ and trans‐hydroperoxide but also, as shortlived intermediates, the corresponding 2‐pinanyloxy radicals. These radicals fragmentate forming a carbon radical with cyclobutane structure whose oxidation products were identified. Besides fragmentation of the 2‐pinanyloxy radical also an intramolecular H‐transfer from the methyl group in 9‐position to the oxygen of the trans‐2‐pinanyloxy radical takes place leading to 9‐hydroperoxy trans‐pinane‐2‐ol.

Relative rates of oxidative attack at the CH bonds in α‐position to the aromatic nucleus were determined for 10 simple alkylaromatic hydrocarbons. The results obtained by competitive oxidations of binary mixtures were shown to be consistent. From these results and the regioselectivity data already published, relative reactivities referring to the tertiary CH bond of cumene were calculated for all CH bonds of the hydrocarbons studied. As expected, p‐alkyl groups increase the reactivity of CH bonds in α‐position to the aromatic nucleus. On the other hand, large alkyl groups, bound to the α‐C atoms, decrease the reactivity of the α‐CH bonds.

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The products of the autoxidation of various simple alkyl aromatic hydrocarbons were reduced by LiAlH4, and the alcohols formed were determined by gas chromatography. In the cases of 2‐phenylbutane, 3‐phenylpentane, and 2‐p‐tolylbutane a considerable fragmentation of the intermediate tertiary alkoxy radicals was proved. On the basis of the analytical results relative reaction rates of the various C–H‐bonds in the hydrocarbons studied were calculated. It is shown that the attack at C–H bonds which are not activated by the aromatic nucleus cannot be neglected and may be of great importance for the kinetics of the oxidation of alkyl aromatic hydrocarbons.

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