| 摘要 |
PURPOSE:To produce 2,4'-dihydroxydiphenyl sulfones useful as a developer for heat-sensitive paper in high selectivity and good yield. CONSTITUTION:The objective method for producing 2,4'-dihydroxydiphenyl sulfones comprises allowing at least one selected from phosphonic acid, phosphinic acid and salts thereof to exist in the reactional system as a catalyst, carrying out reaction in the absence or presence of an aromatic hydrocarbon solvent having 130-200 deg.C boiling point under ordinary pressure in mixing phenols with sulfuric acid, then heating the resultant mixture and producing the objective 2,4'-dihydroxydiphenyl sulfones. |
