High temperature process for preparing fiber reactive dyes

A process for preparing a monoazo dye of the formula:

• ##STR7## wherein the amino linking group may be in the 6, or 7 ring position on the naphthalene ring;
• the moiety D represent a phenylene or naphthylene group;
• R.sub.1 and R.sub.2 are independently selected from hydrogen, sulfo, phosphato, carboxy, hydroxy, C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.4 alkoxy, aryl and halogen;
• R.sub.3 and R.sub.4 are independently selected from hydrogen and C.sub.1 to C.sub.4 alkyl and n and n' are independently an integer from 1 to 3;
• X is selected from chloro, fluoro or --NHCN;
• Y is --CH.dbd.CH.sub.2 or --CH.sub.2 --CH.sub.2 --Z wherein Z represent a leaving group capable of being split off in an alkaline medium which comprises contacting a diazonium salt of an aromatic amine and a coupling component of an amino-4-hydroxy-2-naphthalene sulfonic acid derivative at a temperature from 60.degree. to 85.degree. C. wherein said diazonium salt has the formula:
• (R.sub.1 .sub.n --D--N.sup.+ .tbd.N
• wherein D, R.sub.1 and n are defined above;
• and wherein said a coupling component has the formula:
• ##STR8## wherein R.sub.2, R.sub.3, R.sub.4, X, Y and n' are defined above.