Concentrated, aqueous solutions of salts of acetoacetylamino-arylsulphonic acids and method of forming concentrated solutions of azo dyestuffs therefrom

Claim 1

Process for the preparation of a concentrated dyestuff solution substantially free from foreign ions comprising (a) reacting a compound of the formula H.sub.2 N--R--(SO.sub.3 H).sub.m wherein R is benzene or naphthalene unsubstituted or substituted with fluorine, chlorine, bromine, C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy, C 1 -C 4 -alkylcarbonylamino, C 1 -C 4 -alkylsulphonylamino, phenylazo, naphthylazo, or phenylazo or naphthlazo substituted by methyl, methoxy, chloride, or nitro or is benzene substituted with carboxylcarbonylamino; and m is 1, 2 or 3; with diketene in an aqueous or aqueous-organic solvent while maintaining a reaction pH>3 by adding an amine of the formula ##STR16## wherein R 1 is hydroxyalkyl, alkoxyalkyl or --(C 2 H 4 O) n --R 4 ; R 2 and R 3 are alkyl, hydroxyalkyl, alkoxyalkyl or --(C 2 H 4 O) n --R 4 , or, together with the N atom, are pyrrolidine, morpholine, or piperazine; or by adding an ammonium hydroxide containing a cation of the formula ##STR17## wherein R 1 , R 2 and R 3 are as defined above and R 5 is R 2 or R 3 , to form a concentrated salt solution substantially free from foreign ions of the coupling component of the formula .sub.m (Me.sup.⊕⊖ O.sub.3 S)--R--NHCO--CH.sub.2 --CO--CH.sub.3 wherein Me is ##STR18## (b) reacting the resultant concentrated salt solution with a diazotized amine of the formula A--NH.sub.2 wherein A is the radical of a diazo component to form a concentrated solution of the corresponding azo dyestuff.