Intramolecular H-transfer reactions during the Decomposition of Alkylhydroperoxides in hydrocarbons as the solvents

Abstract

Eight defined primary and secondary alkylhydroperoxides were decomposed in n-alkanes as the solvent, mostly in the presence of manganese stearate. In all cases the corresponding alcohols and carbonyl compounds were formed as the main products with yields of 60–90%. Besides, difunctional products were formed by an intramolecular H-transfer in the alkoxy radicals corresponding to the starting hydroperoxides. Products possibly formed by an intramolecular H-transfer in the corresponding alkylperoxy radical could be found only in the case of 4-methyl-2-hydroperoxy pentane. The amount of products formed by intramolecular H-transfer depended on the nature of the C-H bond in δ-position to the original hydroperoxy group and lay between 4% (primary C-H in the case of 4-hydroperoxy heptane) and 13% (tertiary C-H in the case of 2-hydroperoxy-5-methyl hexane) with respect to the starting hydroperoxide. The amount of products formed by oxidative attack of the alkoxy and alkylperoxy radicals at the normal paraffins used as the solvents was unexpectedly low (always less than 10% with respect to the starting hydroperoxide). An increment system is proposed for the calculation of 13C-nmr shifts in alkyl hydroperoxides.