Liquid chromatographic study of brominated alkylphenols and investigation of product formation in the coulometric bromination of some alkyl-substituted phenols

Abstract

Straight- and reversed-phase liquid chromatography (LC) have been used to study product formation in the coulometric bromination of phenol, 4-alkylphenols and 2,4- and 2,6-dialkyl-substituted phenols. The coulometric method yields predictable, unambiguous products by exchange of hydrogen for bromine in free ortho- and para-positions. The introduction of bromine into an alkylphenol results in an increase in retention on the reversed-phase LC system and there is a linear correlation between the capacity factors for the brominated and non-brominated phenols. In the straight-phase LC system the introduction of bromine into the ortho-positions of 2,4- and 4-alkylphenols results in a marked decrease in retention, while para-substitution of 2,6-alkylphenols causes an increase. Combination of LC and coulometric bromination can be used for the separation of isomeric alkylphenols, e.g., 3- and 4-alkylphenols.