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Catalytic Reduction of 4-Nitrobenzoic Acid by cis-[Rh(CO)2(Amine)2](PF6) Complexes Under Water–Gas Shift Reaction Conditions: Kinetics Study
- Source :
- CATALYSIS LETTERS, Artículos CONICYT, CONICYT Chile, instacron:CONICYT
- Publication Year :
- 2004
- Publisher :
- Springer Science and Business Media LLC, 2004.
-
Abstract
- Rhodium(I) complexes of the type, cis-[Rh(CO)2(amine)2](PF6) where (amine = 3-picoline, 2-picoline, pyridine, 2,6-lutidina or 3,5-lutidine) dissolved in 80% aqueous amine solutions catalyzed the selective reduction of 4-nitrobenzoic acid to 4-aminobenzoic acid under CO atmosphere. The importance of these catalytic systems is their high chemo selectivity for the aromatic nitro group of the 4-nitrobenzoic acid with respect to the carboxylic group, allowing the production of the desired aromatic amine in high yields. The 4-aminobenzoic acid production depends on the nature of the coordinated amine. The Rh/3,5-lutidine system, the most active catalyst among tested, displays turnover frequencies for 4-aminobenzoic acid production of about 173 moles per mole Rh per day for [Rh] = 1 × 10−4 mol, [4-nitrobenzoic acid] = 3.82 × 10−3mol, 10 mL of 80% aqueous 3,5-lutidine, P(CO) = 0.9 atm at 100 °C. Analyses of kinetic results for the Rh/3,5-lutidine system show a first order dependence on 4-nitrobenzoic acid concentration, a non-linear dependence on CO pressure, a segmented Arrhenius plot and dependence on the nature of the reducing gas agent. These data are discussed in terms of a possible mechanism.
Details
- ISSN :
- 1011372X
- Volume :
- 95
- Database :
- OpenAIRE
- Journal :
- Catalysis Letters
- Accession number :
- edsair.doi.dedup.....dad92c128b87b7a687313f131a827023
- Full Text :
- https://doi.org/10.1023/b:catl.0000027287.78214.bf