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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.

Rhodium(I) complexes, cis-[Rh(CO)2(amine)2](PF6) (amine = 4-picoline, 3-picoline, 2-picoline, pyridine, 3,5-lutidine or 2,6-lutidine) dissolved in an aqueous solution of tetrabutylammonium hydrogensulfate (N(C4H9)4HSO4), catalyze the water-gas shift reaction (WGSR). The role of the coordinated amine on the catalytic activity was examined.

The synthesis, characterization, and catalytic properties of the zero-valent, group six metal complex formed by the reaction of [Mo(CO)3(CH3CN)3] and poly(4-vinylpyridine) (P(4-VP)) is described in this work. The pyridyl groups of the organic polymer are covalently bonded to the Mo centers as suggested by X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and Fourier transform infrared (FT-IR) techniques. The polymer-immobilized metal catalyst was also characterized by DTA–TGA, differential scanning calorimetry (DSC) analysis and its morphology and elemental analyses were studied by scanning electron microscopy/energy dispersive X-ray (SEM/EDX) techniques. In the presence of 2-ethoxyethanol the solid is an active catalyst for the heterogeneous hydrogenation of styrene to ethyl benzene.

Catalytic activity for reduction of nitrobenzene to aniline (98%) and azobenzene (2%) using a poly(4-vinylpyridine)-immobilized Cu catalyst [Cu(II)/P(4-VP)] under a CO atmosphere in aqueous 2-ethoxyethanol was studied as a function of the various reaction parameters ([Cu], P(CO), T, and nitrobenzene/Cu molar ratio). Reaction rates were first-order in [Cu]tot over 1.0–12.0 wt.% range and in P(CO) over the 6.8–27.2 atm range. The catalytic activity proved to be non-linear in nitrobenzene/Cu ratio over 41–500 molar ratio range. These results suggest that the rate-limiting step is preceded by reversible coordination of nitrobenzene to a carbonyl–Cu(I) immobilized species. A catalytic mechanism consistent with the data is proposed.

The complex, [Rh(COD)(4-picoline)2](PF6) (COD = 1,5-cyclooctadiene), immobilized on poly(4-vinylpyridine) in contact with methanol catalyzes the hydroesterification and hydroformylation-acetalization of 1-hexene to methylheptanoate, heptanal and 1,1-dimethoxyheptane, respectively. The by-product, 1,1-dimethoxyheptane comes from the nucleophilic addition of methanol over the heptanal formed. Also, H2 and CO2 from the water gas shift reaction (WGSR) are observed. The catalytic activity for the hydroformylation and the WGSR proved to be non-linear in the rhodium total concentration range 0.9-5.0 wt.%.

The hydrodechlorination of chlorobenzene to benzene and biphenyl was studied using poly(4-vinylpyridine)-immobilized Cu catalysts under CO in basic (NaOH, N(C 2 H 5 ) 3 or Na(CH 3 CO 2 )) aqueous 2-ethoxyethanol medium. This Cu system also catalyzed the water gas shift reaction. The catalytic activities for hydrodechlorination of chlorobenzene to benzene were studied as functions of the reaction parameters (nature of the base, reaction time, [Cu], P(CO), T, and S/C). Among the different base studied activity is maximum for NaOH. The rate of benzene formation displays a first-order dependence on [Cu] over the range 1.25 12.50 wt%. This observation was interpreted in terms of the presence of active species having the same nuclearity. The catalytic activity towards benzene formation proved to be first order dependence on P(CO) over the range 5-35 atm. The kinetics behavior with respect to P(CO) leads to the proposal that CO addition to the catalytic species precedes the rate-limiting step. The catalytic activity proved to be non-linear in chlorobenzene/Cu content, over the range 50-400 molar ratio. The results suggest that the rate-limiting step is preceded by reversible oxidative addition of chlorobenzene to Cu immobilized species.

This work describes the catalytic hydroesterification and hydroformylation of 1-hexene by [Rh(cod)(amine) 2 ](PF 6 ) complexes (cod = 1,5-cyclooctadiene; amine = pyridine, 2-picoline, 3-picoline, 4-picoline, 3,5-lutidine or 2,6-lutidine) immobilized on poly(4-vinylpyridine) in contact with methanol under carbon monoxide atmosphere. In the presence of these immobilized complexes, 1-hexene, CO and methanol give methyl-heptanoate and 1,1-dimethoxy-heptane as the main reaction products and minor amounts of heptanal. The acetal by-product comes from the nucleophilic addition reaction of the methanol with the formed heptanal. Other products, such as H 2 and CO 2 coming from the catalysis of the water–gas shift reaction are observed. The reaction products distribution depends on the nature of the coordinated amine to the rhodium center and the reaction parameters.

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.

The stability of Ni/g-Al 2 O 3 catalyst in dry reforming of methane was found to be improved by the addition of MgO into the catalyst, probably due to the formation of out-layer MgAl 2 O 4 spinels, which can effectively suppress the phase transformation to form NiAl 2 O 4 spinel phases, stabilize the tiny Ni crystallites and suppress carbon deposition in dry reforming of methane.

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.

The preparation, characterization and catalytic properties of Rh 2 (CO) 4 Cl 2 immobilized on poly(4-vinylpyridine) are reported. The polymer-immobilized Rh catalyst in contact with 80% aqueous 2-ethoxyethanol is active for the water gas shift reaction and nitrobenzene reduction to azoxybenzene under carbon monoxide at 100 °C. The polymer-immobilized Rh complex was found to be reusable. The Rh complex was coordinatively bonded to the pyridine groups of the organic polymer as suggested by UV–Vis/diffuse reflectance (UV–Vis/DR), Fourier transform infrared (FT-IR), and electron paramagnetic resonance (EPR) spectroscopies. The morphology and the elemental analysis of the immobilized catalyst were studied by scanning electron microscopy–energy dispersive X-ray (SEM–EDX) technique.

Reported here is the influence of the reaction conditions variation (1-hexene/rhodium content (S/C) = 16 - 105, temperature (T) = 70 - 110 °C and carbon monoxide pressure (P(CO)) = 0.6 - 1.8 atm) on the catalytic hydroformylation of 1-hexene to aldehydes (heptanal and 2-methyl-hexanal) by the rhodium(I) complex, [Rh(COD)(2-picoline)2]PF6 (COD = 1,5-cyclooctadiene)immobilized on poly(4-vinylpyridine) in contact with 10 mL of 80% aqueous 2-ethoxyethanol, under water gas shift reaction condition.

Homogeneous catalysts for the water gas shift reaction prepared from Rh2(μ-Pz)2(COD)2 (Pz = pyrazolate ion and COD = 1,5-cyclooctadiene) in aqueous organic solvent media (pyridine, 4-picoline or 2-ethoxyethanol) and Rh2(μ-Pz)2(CO)2(TPPMS)2 (TPPMS = meta-sulfonatophenyl-diphenyldiphosphine) in acidic aqueous media under mild conditions are described. In situ FT-IR, 1H and 13C NMR spectroscopic studies of the Rh2(μ-Pz)2(COD)2 catalytic system reveal the presence of hydrido-Rh complexes with linear and bridging carbonyls. These complexes also catalyze the reduction of nitrobenzene to aniline.

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.

In this work, a mechanistic study of the hydroxycarbonylation of 1-hexene to heptanoic acid and the water gas shift reaction (WGSR) catalyzed by the rhodium(I) complexes, [Rh(COD)(amine)2](PF6) (COD = 1,5-cyclooctadiene, amine = 4-picoline, 3-picoline, 2-picoline, pyridine, 3,5-lutidine or 2,6-lutidine) immobilized on poly(4-vinylpyridine) in contact with water under CO is discussed. Catalytic cycles for these reactions bearing common Rh-H catalytic species are proposed.

This paper describes the catalytic activation studies of the reduction of some 2-substituted-5-nitrofuran compounds by [Rh(COD)(2-picoline)2](PF6) (COD = 1,5-cyclooctadiene) anchored on poly(4-vinylpyridine) in contact with 80% aqueous 2-ethoxyethanol at 100 º C under carbon monoxide atmosphere. The effect of varying the nature of the 2-substituents of the furan ring was evaluated. The importance of the present catalysis studies can be emphasized, because the potential activity against bacteria of the 2-substituted-5-nitrofuran compounds could be monitored by determining the facility of catalytic reduction of the nitro group

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 are the in situ FT-IR and 13C-NMR spectroscopic studies of the complex cis-[Ir(CO)2(py)2](PF6 ) (py = pyridine) dissolved in 80% aqueous pyridine used as a precursor in the homogeneous catalysis of the water gas shift reaction (WGSR, CO + H2O AE CO2 + H2). These spectroscopy studies reveal the presence of aminocarbonyliridium complexes with linear and bridging carbonyls groups as reaction intermediates. The WGSR catalysis by Ir4(CO)12 complex dissolved in 80% of aqueous 4-picoline or pyridine under 1.9 atm of CO at 100 C and the FT-IR and 1H-NMR in situ studies of the pyridine promoted disproportionation of Ir4(CO)12, are also described

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