Reaction Pathways and the Role of Solvent in the Hydrogenation of Chloronitrobenzenes

• Published in: Collection of Czechoslovak chemical communications Vol. 68; no. 10; pp. 1819 - 1832
• Main Authors: Krátky, Vieroslav, Králik, Milan, Kaszonyi, Alexander, Stolcová, Magdaléna, Zalibera, Lubomír, Mecárová, Miroslava, Hronec, Milan
• Format: Journal Article
• Language: English
• Published: 01-01-2003
• ISSN: 0010-0765; 1212-6950
• DOI: 10.1135/cccc20031819

Liquid phase hydrogenation of chloronitrobenzenes to corresponding chloroanilines over Pd on carbon (Pd/C) under mild reaction conditions was studied. On the basis of
1
H,
13
C NMR, GC-MS and HPLC analyses of reaction mixtures, the reaction pathways were evaluated. The reduction of substrates proceeds
via
the formation of chloronitrosobenzenes and
N
-(chlorophenyl)hydroxylamines and mainly results in the formation of the chloroanilines and aniline. Aniline is formed by hydrogenolysis of chlorine (dechlorination) in benzene ring. Other compounds (mono- and disubstituted azobenzenes and azoxybenzenes) were also detected by GS-MS and HPLC (<3 mole %). The used solvent influences the reaction mixture composition and catalyst activity.