Neopentane radical attack

Traces of hydrocarbons have been added to slowly reacting H2 + 02 mixtures in aged boric-acid-coated vessels at 480°-500°C. Measurements of hydrocarbon loss and H20 formation have enabled relative velocity constants for the attack of the radicals H, O, OH, and H02 on the additive to be assessed for CH,t and C2H6. With CHhy the results also show that CHS radicals react at almost equal rates with H2 and 02 at 500 mm. Hg pressure, and that the reaction with 02 appears to have both second- and third-order components. Detailed analyses of the reaction products obtained with ethane and neopentane enable the reactions of the radical produced in the primary attack to be elucidated, and mechanisms to account for the various products are given. 

The N-haloimide halogenations are also controlled partially by the fact that Cl or the iV-succinimidyl radical are much more reactive than Br in hydrogen abstracting reactions and, towards a hydrocarbon of low reactivity such as neopentane, a bromine atom chain would be quite ineffective. With mixtures of NBS and CI2, halogenation occurs to form the alkyl bromides but with the selectivity expected for chlorine atom attack Apparently ClBr is formed and reacts with the alkyl radical to form RBr and a chlorine atom. A similar situation exists for the bromination of alkanes using a mixture... 

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