Separation of close boiling substituted phenols by dissociation extraction

Abstract

Some mixtures of substituted phenols, which are difficult to separate by established methods such as distillation, crystallisation, etc., have been separated by dissociation extraction. Di- n-butyl ether was found to be an excellent solvent for the systems: phenol- o-chlorophenol; p-chlorophenol-2,4-dichlorophenol; o-cresol-6-chloro-o-cresol. In the case of m-cresol-2,6-xylenol and p-cresol-2,6-xylenol, benzene was found to be a good solvent. For the system: 4-chloro-m-xylenol-2,4-dichloro-m-xylenol dissociation extraction in a solid-liquid system without a solvent gave higher values of separation factor than a liquid-liquid system. In all the cases, agreement between the experimental and theoretical values of separation factors was found to be reasonable.