Process for the preparation of azo dyestuffs

Claim 1

Process for the preparation of an azo dyestuff free from sulfonic acid groups comprising a. diazotizing an amine which is not diazotizable in dilute aqueous mineral acids of the formula: ##STR9## wherein X is Cl, Br, or I; and Y is F, Cl, Br, CF 3 , CN, NO 2 , COR 6 , or SO 2 R 6 ; and wherein R 6 is C 1 -C 4 -alkyl, cyclohexyl, phenyl, chlorophenyl, tolyl or methoxyphenyl; in a lower aliphatic carboxylic acid nitrile or in tetrahydrothiophene-1,1-dioxide or derivative thereof; b. adding the resulting solution or dispersion of the diazonium salt to an aniline of the formula: ##STR10## wherein R 1 is H; C 1 -C 4 -alkyl; C 1 -C 4 -alkyl monosubstituted by OH, Cl, OCOR 5 , OCO 2 R 5 , OCONH 2 , OCONHR 5 , CN, or OR 5 or phenyl-C 1 -C 4 -alkyl; R 2 is R 1 , cyclohexyl or phenyl; R 3 is H, CH 3 , OCH 3 or OC 2 H 5 ; R 4 is H, CH 3 , Cl, OCH 3 , OC 2 H 5 , CN, NHCOR 5 , NHCO 2 R 5 , NHSO 2 R 5 , NHCONH 2 or NHCONHR 5 ; and R 5 is C 1 -C 4 -alkyl, cyclohexyl, phenyl, chlorophenyl, tolyl or methoxyphenyl in a solvent consisting essentially of a neutral organic dipolar aprotic solvent to effect a coupling reaction and form an o-halogenazodyestuff; and c. effecting a nucleophilic halogen exchange of an o-halogen atom of the resultant o-halogen azo dyestuff in the resultant reaction medium after neutralization thereof without intermediate isolation of the dyestuff.