Patent ID: 7371324

Claim:
A process for extracting from aqueous solution the alkali metal or ammonium salt of a phenol, naphthol, anthrol or phenanthrol or the corresponding thiol, comprising: a) (i) providing a preformed aqueous alkaline or neutral solution of the alkali metal or ammonium salt of the phenol, naphthol, anthrol or phenanthrol or the corresponding thiol; or (ii) preparing an aqueous alkaline or neutral solution of the alkali metal or ammonium salt of the phenol, naphthol, anthrol or phenanthrol or the corresponding thiol by treating the phenol, naphthol, anthrol or phenanthrol or the corresponding thiol with an alkali metal hydroxide in water; b) dissolving an alkali metal or ammonium fluoride, chloride, bromide, hydroxide, nitrate, nitrite, sulphate, sulphite, sulphide, thiosulphate, phosphate, hydrogen phosphate, carbonate, bicarbonate, cyanate, cyanide, thiocyanate, borate, chlorate, chlorite, hypochlorite, perchlorate, chromate, dichromate or permanganate in the aqueous alkaline or neutral solution of the salt of the phenol, naphthol, anthrol or phenanthrol or the corresponding thiol; c) adding a partially water-miscible organic solvent to the aqueous alkaline or neutral solution so as to transfer the aqueous salt of the phenol, naphthol, anthrol or phenanthrol or corresponding thiol into the solvent while retaining separate aqueous and solvent phases; d) stirring or otherwise agitating the resultant two-phase system until no further salt of the phenol, naphthol, anthrol or phenanthrol or the corresponding thiol is extracted into the solvent phase; e) separating the solvent phase from the aqueous phase; the ratio of solvent to water in the separated solvent phase being from 0.5:1 to 10:1 w/w.