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This work describes the carbonylation of hex-1-ene, cyclohexene, 2,3-dimethyl-but-1-ene and 2-methyl-pent-2-ene, their quaternary mixture and a real Venezuelan naphtha, catalyzed by a rhodium(I) [Rh(cod)(4-picoline)2](PF6) (cod = 1,5-cyclooctadiene) complex immobilized on poly(4-vinylpiridine) (P(4-VP)) in contact with methanol under carbon monoxide atmosphere. The conversion (%) of olefins to carbonylated products for the individual olefins decreases in the order: hex-1-ene (63) > cyclohexene (58) > 2,3-dimethyl-but-1-ene (50) > 2-methyl-pent-2-ene (31), under the following conditions: 0.5 g of P(4-VP) for [Rh] = 2 wt.% (1 × 10−4 mol), 10 mL of CH3OH, [olefin] = 1 × 10−2 mol, S/C = 100, P(CO) = 33 atm at 110 °C for 24 h. Other products such as H2 and CO2 coming from the catalysis of the water–gas shift reaction are observed. In this work, the carbonylation of hex-1-ene, cyclohexene, 2,3-dimethyl-but-1-ene and 2-methyl-pent-2-ene, their quaternary mixture and a real Venezuelan naphtha, catalyzed by a rhodium(I) [Rh(cod)(4-picoline)2](PF6) (cod = 1,5-cyclooctadiene) complex immobilized on poly(4-vinylpiridine) (P(4-VP)) in contact with methanol under carbon monoxide atmosphere is described.

In aqueous solution of tetrabutylammonium hydrogensulfate (N(C4H9)4HSO4), rhodium complexes like cis-[Rh(CO)2(amine)2](PF6) (amine = pyridine, 4-picoline, 3-picoline, 2-picoline, 3,5-lutidine or 2,6-lutidine) promote the carbonylation of 1-hexene to heptanoic acid and heptanal under carbon monoxide atmosphere. Gaseous by-products (H2 and CO2) from the catalysis of the water–gas shift reaction (WGSR) are also observed. The catalytic activities for heptanoic acid and heptanal production depend on the nature of the coordinate amine to the rhodium center for [Rh] = 1 × 10−4 mol, [1-hexene] = 0.05 mol, 40 mL of water (2.2 mol); 2.4 g of N(C4H9)4HSO4 (5.6 wt.%), S/C = 500, P(CO) = 22 atm at 150 °C. Analyses of kinetic results for the Rh/4-picoline system (one of the more active and the most stable catalyst among tested) towards the carbonylation reaction for the organic products formation show a nonlinear dependence on total rhodium concentration and on N(C4H9)4HSO4 amount in the range of studies. The last result suggested that the salty medium stabilize the ionic Rh catalytic species formed under the reaction conditions, therefore enhancing the reactivity. The increase in P(CO) is accompanied by improvement in the catalytic activities of oxygenated products, then reaches a maximum and starts decreasing at higher P(CO). These data are discussed in terms of catalytic cycles bearing a common Rh–H catalytic species.

The rhodium(I) complexes, cis-[Rh(CO)2(amine)2](PF6) (amine = pyridine, 2-picoline, 3-picoline, 4-picoline, 3,5-lutidine or 2,6-lutidine) dissolved in methanol under carbon monoxide atmosphere are effective catalysts for the hydroesterification and hydroformylation–acetalization of 1-hexene. In the presence of these soluble complexes, 1-hexene, CO and methanol give methyl-heptanoate and 1,1-dimethoxy-heptane as major products, and minor amounts of heptanal. The acetal product comes from the nucleophilic addition reaction of the methanol with the formed heptanal. Gaseous by-products (H2 and CO2) from the catalysis of the water–gas shift reaction (WGSR) are also observed. The reaction products distribution depends on the nature of the coordinated amine to the rhodium center. The effects of the reaction variables such as CO pressure, temperature, catalyst concentration, 1-hexene/Rh molar ratio and reaction medium, were also examined. These data are discussed in terms of catalytic cycles, and it is concluded that common Rh–H catalytic species are involved.

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.

In this work the results of the study of the catalytic activity of the dinuclear gem-dithiolato-bridged rhodium complex [Rh2(μ-S2CBn2)(cod)2] (Bn = benzyl; cod = 1,5-cyclooctadiene) for the hydroformylation of hex-1-ene in CO/H2O, are presented. Under the best conditions for hydroformylation [P(CO) = 22 atm at 80 °C, in 24 h, toluene/H2O = 8/2, v/v, hex-1-ene (3 mmol), [Rh] = 0.01 mmol, hex-1-ene/[Rh] = 15 molar ratio] the only organic products observed (detected by GC and GC-MS) were heptanal and 2-methylhexanal and traces of 2-hexene (isomerization product). In addition, the products of the water gas shift reaction, H2 and CO2, were also obtained as competitive reaction of the hydroformylation process., This work was supported by FONACIT (S1-2002000260) and CDCH-UCV (PG. 03-00-6928-2007). The authors are gratefully to CYTED: Red V-D and Project V-9, and Ministerio de Educación y Ciencia (MEC/FEDER) Project CTQ2006-03973/BQU.

The catalytic reduction of nitrobenzene by rhodium(I) complexes of the type cis-[Rh(CO) 2 (amine) 2 ](PF 6 ) (amine = 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, or 2,6-dimethylpyridine) in methanol under an atmosphere of carbon monoxide is described. A single organic product, aniline, is seen in the post-reaction mixture. The amount of product formed depends upon the nature of the amine coordinated to the rhodium center.

The catalysis of the hydroesterification and hydroformylation-acetalization of 1-hexene by rhodium(I), cis-[Rh(CO)2(amine)2](PF6) complexes (amine = pyridine, 2-picoline, 3-picoline, 4-picoline, 3,5-lutidine or 2,6-lutidine) dissolved in 10 mL of ethanol or 10 mL of 80% aqueous ethanol, 0.4 mL (3 x 10-3 mol) of 1-hexene, [Rh] = 5 x 10-5 mol, 1-hexene/Rh = 64 under P(CO) = 0.9 atm at 100 °C for 4 h, is described in this work. The mayor products are ethyl-heptanoate, heptanal and 1,1-diethoxyheptane coming from the hydroesterification, hydroformylation reactions and the nucleophilic addition reaction of the ethanol over the formed heptanal, respectively. The reaction product distribution depends on the nature of the coordinate amine to the rhodium center

Reported here is the catalytic studies of the hydroformylation and the isomerization of 1-hexene to aldehydes (heptanal and 2-methyl-hexanal) and 2-hexene, respectively by [Rh(COD)(amine)2]PF6 complexes (COD = 1,5-cyclooctadiene, amine = 4-picoline, 2-picoline or 2,6-lutidine) immobilized on poly(4-vinylpyridine) in contact with 10 mL of 80% aqueous 2-ethoxyethanol, under CO atmosphere (0.9 atm at 100 C). The results of these studies show the following reactivity order defined as Turnover Frequencies for aldehydes production: 2-picoline {2.9} > 4-picoline {2.6} > 2,6-lutidine {2.4}. The electronics and steric effects induced by the amine ligands apparently influence on the observed catalytic activities. The [Rh(COD)(2-picoline)2]PF6/poly(4-vinylpyridine) system also catalyzed the hydroformylation and isomerization of 1-octene

Kinetic studies of the water gas shift reaction have been carried Æt in the presence of [Rh(COD)(4-picoline)2]P F6, (COD = 1,5-cyclooctadiene) as catalyst, immobilized on poly(4-vinylpyridine) 2% cross linked with divinylbenzene in contact with a mixture of 80% aqueous 2-ethoxyethanol. The rhodium complex was anchored to the pyridine groups of the organic polymer. Analyses of kinetic results show a first order dependence on carbon monoxide pressure, a nonlinear dependence on rhodium total concentration and a segmented Arrhenius plot. These data are discussed in terms of a possible mechanism. Estudios cinéticos de la reacción de desplazamiento del gas de agua se llevaron a cabo en presencia del complejo [Rh(COD)(4-picolina)2]P F6, (COD = 1,5-ciclooctadieno) como catalizador, inmovilizado en poli(4-vinilpiridina) entrecruzado con 2% de divinilbenceno en contacto con una mezcla de 80% de 2-etoxietanol acuoso. El complejo de rodio fue anclado a los grupos piridínicos del polímero orgánico. Los análisis de los resultados de los estudios cinéticos muestran que la reacción en el sistema heterogenizado sigue una dependencia de primer orden con respecto a la presión de monóxido de carbono, una dependencia no lineal con respecto a la concentración de rodio total y muestra una curva de Arrhenius segmentada. Estos resultados son discutidos en términos de un posible mecanismo