Process for the manufacture of nuclear-sulphonated compounds

Process for the manufacture of nuclear-sulfonated aromatic compounds which comprises reacting (1) at most tricyclic homocyclic aromatic amino compounds with 1 or 2 amino groups directly bonded to the aromatic ring system and which compounds contain as further substituents halogen, alkyl, halogenoalkyl, alkoxyalkyl, carboxyalkyl, alkoxy, alkoxyalkoxy, carboxyl, alkoxycarbonyl, carbamoyl, nitrile, nitro, alkylsulphonyl, phenylsulphonyl, sulpho, sulphamoyl, alkylmercapto, phenylmercapto or phenoxy where alkyl contains 1 to 8 carbon atoms with (2) a sulfonating agent of the formula ##EQU4## wherein M is hydrogen, the ammonium cation or an ammonium ion of the formula R R.sub.1 NH.sub.2 --.sup.+, R is hydrogen, alkyl with 1 to 8 carbon atoms or cycloalkyl with 5 or 6 carbon atoms, and R.sub.1 is hydrogen or alkyl with 1 to 8 carbon atoms in the presence of (3) a catalyst which is N-methyl-pyrrolid-2-one, .SIGMA.-caprolactam, or N-methyl-piperid-2-one in an aprotic solvent at temperatures between 20.degree. and 250.degree.C.