Separation and determination of chlorobenzoic acid isomers by salting-out chromatography

Abstract

A method of separation of o-, m- and p-chlorobenzoic acids by salting-out chromatography and of their determination by U. V. spectrophotometry has been presented, in which the stationary phase is weak-acid resin Amberlite CG-50 (sodium form), the mobile phase is acidic aqueous salt solution of varying concentrations, and the salting-out agent is aqueous or alcoholic aqueous solution of sodium chloride. The distribution coefficients of three isomers increased with increasing sodium chloride concentration and with decreasing pH over the range 2.05.0. That of m-isomer also increased with increasing concentration of ethyl alcohol over the range 05%.
Quantative separation of the three isomers has been accomplished by a column of φ 10 mm × 150 mm and 2 M aqueous solution of sodium chloride of pH 3.5 containing 5% ethy J alcohol.