Collect. Czech. Chem. Commun.
2003, 68, 1819-1832
https://doi.org/10.1135/cccc20031819
Reaction Pathways and the Role of Solvent in the Hydrogenation of Chloronitrobenzenes
Vieroslav Krátkya, Milan Králikb, Alexander Kaszonyia, Magdaléna Stolcováa, Lubomír Zaliberac, Miroslava Mecárováa and Milan Hroneca,*
a Department of Organic Technology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovak Republic
b VÚCHT a.s., Nobelova 34, 836 03 Bratislava, c/o Department of Organic Technology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovak Republic
c Department of Physical Chemistry, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovak Republic
Abstract
Liquid phase hydrogenation of chloronitrobenzenes to corresponding chloroanilines over Pd on carbon (Pd/C) under mild reaction conditions was studied. On the basis of 1H, 13C 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.
Keywords: Reaction pathways; Chloronitrobenzenes; Catalyst activity; Selectivity; Deactivation; Catalyst surface hydrophobicity; Solvent effects; Heterogeneous catalysis; Reductions; Palladium.
References: 20 live references.
