Hydrogen exchange in heterolytic reactions. Exchange of hydrogen atoms in the replacement of iodine in alkyl iodides

Abstract

1. The possibility of applying the hydrogen-exchange reaction in the study of the, mechanism of heterolytic reactions was investigated. A study was made of hydrogen exchange a) in the hydrolysis of tertiary alkyl iodides (tert-C4H9I and tert-C5H11I) with water enriched with deuterium oxide, and b) during the exchange of iodine for another iodine atom in alkyl iodides (C2H5I, i-C3H7I, tert-C4H9I, and tert-C5H11I) in reaction with 56% HI enriched with deuterium iodide. 2. It was shown that hydrogen exchange in C-H bonds is observed in those reactions which, according to kinetic investigations, proceed by a unimolecular mechanism, i.e. with intermediate formation of carbonium ions. It was shown, in particular, that the hydrolysis of tertiary alkyl iodides (C4H9I and C5H11I) and replacement of iodine by iodine in tertiary alkyl iodides, which proceed by an SN1 mechanism, are accompanied by hydrogen exchange reactions of secondary and primary alkyl iodides, which permits us to assume a bimolecular mechanism for these reactions.