GB739907A - Recovery of phenols - Google Patents

Abstract

A process for the production of resorcinol by the catalytic cleavage of a reaction mixture containing meta-di-isopropylbenzene hydroperoxide derived from the oxidation of meta-di-isopropylbenzene comprises decomposing by the action of heat the material contained in the cleavage reaction product which is less volatile than resorcinol and recovering the additional quantities of resorcinol and the meta-isopropenylphenol so formed. The heat treatment may be conducted in presence of an acid catalyst or, alternatively, the cleavage reaction product is treated to remove or neutralize cleavage catalysts and stripped of low-boiling materials before being subjected to heat treatment. The heat treatment is also preferably conducted at 200-400 DEG C. at super- or sub-atmospheric pressures and in presence of a high-boiling inert diluent (preferably boiling at or above 200 DEG C., e.g. tri-isopropyl- or 1 : 2 : 4-trichlorobenzene; isopropyl-, methyl-, chloro- or bromonaphthalene; a gas oil fraction; or a mixture thereof), the heat-treated cleavage reaction product being distilled and the resorcinol and meta-isopropenylphenol recovered from the distillate preferably by crystallization and filtration, or by distilling directly into water. The heat treatment and distillation are preferably conducted simultaneously, and the proportion of high-boiling inert diluent is preferably adjusted so that the distillate is not saturated with respect to resorcinol while still above the temperature at which crystallization takes place. Further quantities of resorcinol may be recovered from solution in the inert diluent mother-liquors by extraction with water; meta-isopropenylphenol is also recovered by extracting the resorcinol-free inert diluent with an aqueous alkaline solution. Mixed resorcinol/meta-isopropenylphenol phases are separated (1) by extraction with a solvent, e.g. benzene, toluene, methyl-naphthalene, chloroform or carbon tetrachloride; or (2) by partition between two immiscible solvents, e.g. water and one of the solvents in (1). The resorcinol, after separation from the meta-isopropenyl phenol, may be further purified by redistillation, or by sublimation.