反应详情

Since almost no water is contained in the reaction mixture, it is preferable that 4,4′-dihydroxydiphenylsulfone is separated by crystallization by adding phenol to the reaction mixture. The amount of the crystallized 4,4′-dihydroxydiphenylsulfone to provide the content of 2,4′-dihydroxydiphenylsulfone greater than the content of 4,4′-dihydroxydiphenylsulfone in the filtrate obtained by the crystallization of 4,4′-dihydroxydiphenylsulfone, followed by the filtration, can be calculated, and the amount of the added phenol can be obtained based on the solubility using the amount obtained by the calculation. The filtrate having a content of 2,4′-dihydroxydiphenylsulfone greater than the content of 4,4′-dihydroxydiphenylsulfone can be obtained as follows: phenol is added to the reaction mixture; the resultant mixture is heated until the entire fluid becomes homogeneous; the heated fluid is cooled, and crystals of 4,4′-dihydroxydiphenylsulfone are allowed to grow sufficiently and then separated by filtration. Since the crystals of 4,4′-dihydroxydiphenylsulfone separated by the filtration contains phenol and phenolsulfonic acid, it is preferable that the crystals are washed with hot water and dried. The obtained 4,4′-dihydroxydiphenylsulfone has a purity of 95% by weight or greater.

1. customis separated by crystallization
2. additionby adding phenol to the reaction mixture