Process for the preparation of azo dyestuffs

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.sub.3, CN, NO.sub.2, COR.sub.6, or SO.sub.2 R.sub.6 ;
• and wherein
• R.sub.6 is C.sub.1 -C.sub.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.sub.1 is H;
• C.sub.1 -C.sub.4 -alkyl;
• C.sub.1 -C.sub.4 -alkyl monosubstituted by OH, Cl, OCOR.sub.5, OCO.sub.2 R.sub.5, OCONH.sub.2, OCONHR.sub.5, CN, or OR.sub.5 or phenyl-C.sub.1 -C.sub.4 -alkyl;
• R.sub.2 is R.sub.1, cyclohexyl or phenyl;
• R.sub.3 is H, CH.sub.3, OCH.sub.3 or OC.sub.2 H.sub.5 ;
• R.sub.4 is H, CH.sub.3, Cl, OCH.sub.3, OC.sub.2 H.sub.5, CN, NHCOR.sub.5, NHCO.sub.2 R.sub.5, NHSO.sub.2 R.sub.5, NHCONH.sub.2 or NHCONHR.sub.5 ;
• and
• R.sub.5 is C.sub.1 -C.sub.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.