Preparation of 2,6-dinitroanilines

A method for the manufacture of a compound of the formula:

• ##STR18## wherein Y is alkyl C.sub.1 -C.sub.4, halogen or CF.sub.3 ;
• Z is hydrogen, halogen, alkyl C.sub.1 -C.sub.4, alkoxy C.sub.1 -C.sub.4, monohaloalkyl C.sub.1 -C.sub.4, or monoalkoxy (C.sub.1 -C.sub.4) alkyl (C.sub.1 -C.sub.4);
• R.sub.1 represents alkyl C.sub.1 -C.sub.6, cycloalkyl C.sub.4 -C.sub.6, monohaloalkyl C.sub.1 -C.sub.4 or alkoxyalkyl where the alkyl group is C.sub.1 -C.sub.4 and the alkoxy group is C.sub.1 -C.sub.4 ;
• R.sub.2 is hydrogen or one of the groups of R.sub.1 ;
• comprising reacting an N-alkylated aniline of the formula:
• ##STR19## wherein R.sub.1, R.sub.2, Y and Z are as defined above and W and V are hydrogen or nitro provided W and V are not both nitro;
• with a three-component nitrating agent having a composition with the following limits:
• 60% HNO.sub.3, 8% H.sub.2 SO.sub.4, 32% H.sub.2 O;
• 50% HNO.sub.3, 35% H.sub.2 SO.sub.4, 15% H.sub.2 O;
• 2% HNO.sub.3, 68% H.sub.2 SO.sub.4, 30% H.sub.2 O;
• 2% HNO.sub.3, 20% H.sub.2 SO.sub.4, 78% H.sub.2 O;
• at a temperature in the range of from 0.degree. C. to 70.degree. C.;
• further characterized in that, when W and V are hydrogen in the N-alkylated aniline, from 2.2 to 5.0 moles of nitric acid are employed per mole of the N-alkylated aniline and, when one of W and V in the N-alkylated aniline is nitro, the moles of nitric acid per mole of N-alkylated aniline is in the range of 1.2 to 4.0 moles and when a compound of the formula:
• ##STR20## wherein R.sub.1 Y and Z are as defined above is formed in the reaction mixture denitrosating the reaction mixture.