Method of producing A 2,4'-dihydroxydiphenylsulfone

A method of producing in high purity the 2,4'-isomer of the dihydroxydiphenylsulfone which comprises producing a crude 2,4'-dihydroxydiphenylsulfone by by reacting a phenol or a mixture of phenols with sulfuric acid, in the presence of at least one of phosphonic acid, phosphinic acid and salts thereof and in the absence of a solvent or in the presence of an aromatic hydrocarbon solvent having a boiling point at atmospheric pressure of 130.degree. to 200.degree. C. and purifying the crude 2,4'-isomer thus produced by selective solution in a mixed solvent containing 5 to 20 weight % of at least one lower aliphatic alcohol and 95 to 80 weight % of at least one aromatic hydrocarbon which does not contain halogen, cooling the solvent mixture to precipitate the thus-purified 2,4'-isomer therefrom and separating the precipitated 2,4'-isomer from the solvent mixture.

A method of producing in high purity the 2,4'-isomer of a dihydroxydiphenylsulfone which comprises producing a crude 2,4'-dihydroxydiphenylsulfone by reacting a phenol or a mixture of phenols with sulfuric acid, in the presence of at least one of phosphonic acid, phosphinic acid and salts thereof and in the absence of a solvent or in the presence of an aromatic hydrocarbon solvent having a boiling point at atmospheric pressure of 130.degree. to 200.degree. C. and purifying the crude 2,4'-isomer thus produced by selective solution in a mixed solvent containing 10 to 40 weight % of at least one ketone and 90 to 60 weight % of at least one aromatic hydrocarbon which does not contain halogen, cooling the solvent mixture to precipitate the thus-purified 2,4'-isomer therefrom and separating the precipitated 2,4'-isomer from the solvent mixture.

A method of producing in high purity the 2,4'-isomer of a dihydroxydiphenylsulfone which comprises producing a crude 2,4'-dihydroxydiphenylsulfone by reacting a phenol or a mixture of phenols with sulfuric acid, in the presence of at least one of phosphonic acid, phosphinic acid and salts thereof and in the absence of a solvent or in the presence of an aromatic hydrocarbon solvent having a boiling point at atmospheric pressure of 130.degree. to 200.degree. C. and purifying the crude 2,4'-isomer thus produced by selective solution in a mixed solvent containing 10 to 40 weight % of at least one ester of acetic acid and 90 to 60 weight % of at least one aromatic hydrocarbon which does not contain halogen, cooling the solvent mixture to precipitate the thus-purified 2,4'-isomer therefrom and separating the precipitated 2,4'-isomer from the solvent mixture.