To produce a diarysulfonic acid that is useful as a modifier or intermediate for various resins, such as polyamides, polyesters, polyimides and polysulfons, efficiently at a low cost.
This diarysulfonic acid of formula I (Ar is benzene or naphthalene; X and Y are each a 1-20C alkyl, nitro, amino etc.; (m) and (n) are each an integer of 0-3), e.g. 3,3',4,4'-tetramethyldiphenylsulfon, is obtained by a condensation reaction of an aromatic compound of the formula of (X)m-Ar-(Y)n with sulfuric acid or an aromatic sulfonic acid of formula II in the presence of a catalyst. The aromatic compound distilled off in the process of the condensation and/or the aromatic compound to be additionally fed are vaporized and the vapor of the aromatic compound is fed into the reaction liquid.
TAKATAKE MASAHIRO
NISHIUCHI AKIHIRO
TAKATSUJI SHIGEO
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