Process for manufacturing aromatic diamines

DETAILED DESCRIPTION What is claimed is: 1.
Process for preparing an aromatic diamine having the formula ##STR5## wherein R is an alkyl or alkoxy group having up to 6 carbon atoms which comprises contacting in the presence of a solvent selected from the group consisting of aniline, O-toluidine and m-toluidine a dinitro compound of the formula ##STR6## wherein R is as defined above with hydrogen in the presence of a catalyst containing at least one metal of period 5 or 6 of Group VII of the Periodic Table, said catalyst being present in an amount of 0.
0005 to 0.
1% by weight metal, based upon the amount of dinitro compound being reacted.
2.
Process of claim 1 wherein the metal is palladium.
3.
Process of claim 1 wherein the metal is palladium and said palladium is deposited on active charcoal.
4.
Process of claim 1 wherein the amount of catalyst is 0.
005 to 0.
02% by weight of nobel metal based on the amount of dinitro compound employed.
5.
Process of claim 1 wherein the solvent is selected from the group of, O-toluidine and m-toluidine.
6.
Process according to claim 1 wherein the solvent is O-toluidine.
7.
Process according to claim 1 wherein the solvent is m-toluidine.




Description:
BACKGROUND This invention relates to a process for the manufacture of aromatic diamines by catalytic hydrogenation of the corresponding dinitro compounds.
The catalytic reduction of dinitro compounds is a problem which has remained unsolved in many cases.
The processes known in individual cases can in general not be applied with equal success to other starting compounds (German Pat.
No.
948,784).
SUMMARY It has now been found that aromatic diamines of the formula ##STR3## in which R denotes a alkyl or alkoxy radical with up to 6 C atoms Are obtained in good yield when dinitro compounds of the formula ##STR4## in which R has the abovementioned meaning are treated with hydrogen in the presence of one or more noble metals of periods 5 and 6 of Group VIII of the Periodic Table (as shown on the end page of "Advanced Inorganic Chemistry," Cotton & Wilkinson, 1966, 2nd Edition, Interscience), as the catalyst and of optionally substituted aniline as the solvent