| abstract |
Process for preparing 2-naphthylamino-6,8-disulfonic acidnacid by Bucherer reactionnso that they react with ammonia in the presencensulfite or bisulfite anionsnat a temperature of 140 to 195 ° C and a pressure of 1 ° Cnup to 4 MPa is subjected to a 2-naphthol-6,8-disulfonic double-ammonium saltnacid, withnthe molar ratio of the 2-naphthol-6,8-disulfonic divalent saltnacid and ammonia 1: 3nto 9, and preferably 1: 5.n2-naphthylamino-6,8-disulfonic acidnused as a dye intermediate. |