PROCESS FOR THE CATALYTIC REDUCTION OF NITRO-AROMATIC COMPOUNDS

摘要

There is described a process for the catalytic reduction of nitro-aromatic compounds by the transfer of hydrogen from alcohols to nitro-aromatic compounds said reduction being catalyized by iridium complexes, in which a primary or secondary alcohol of formula (I) or a glycol: < IMG > (I) is reacted with a nitro-aromatic compound of formula (II): Ar - (NOy)x (II) wherein: R and R1, which may be the same or Different, each represent a hydrogen atom or a hydrocarbon group having up to 30 carbon atoms or together represent a carboxcylic or heterocylic group, which groups may be substituted by groups inert under the reaction conditions; Ar represents an aryl or hetero-aryl group, which may be substituted by groups inert under the reaction conditions; x and y, which may be the same or different, represent 1 or 2, in the presence of a complex catalyst of iridium having the formula (III) or (IV): ¢Ir Chel (L-L)! X and Ir Chel (L)2Y (III) (IV) wherein: Chel represents a chelating bivalent nitrogeneous compound; L-L represents a molecule of a diolefine, preferably non-conjugated; L represents a mono-olefine molecule; X? represents an anion selected from Cl?, Br?, I?, PF?, BF?, C10?, B(C6H5)?, OH?, < IMG > wherein R and R1 have the aforesaid meanings; and Y is halogen, preferably Cl, Br or I; and optionally with a mineral alkaline compoind, at a temperature between about 20.degree.C and the boiling temperature of the reaction mass. The compounds thus obtained are derivatives of the partial or total hydrogenation of the nitro-aromatic starting compounds constituted by anilines or aryl-amines in general, aryl-hydroxylamines, aryl-hydrazo compounds and aryl-azo compounds. These compounds are useful as intermediates for organic syntheses in general, in the field of fine chemicals.