123-72-8Relevant articles and documents
Supported homogeneous catalyst makes its own liquid phase
Kaftan, Andre,Sch?nweiz, Andreas,Nikiforidis, Ioannis,Hieringer, Wolfgang,Dyballa, Katrin M.,Franke, Robert,G?rling, Andreas,Libuda, J?rg,Wasserscheid, Peter,Laurin, Mathias,Haumann, Marco
, p. 32 - 38 (2015)
A catalyst designed for homogeneous catalysis is shown to generate its own liquid phase if deposited onto a support. In this way, a macroscopically heterogeneous catalyst generates a microscopically homogeneous catalytic environment by self-organization. 2,2′-((3,3′-di-tert-butyl-5,5′-dimethoxy-[1,1′-biphenyl]-2,2′-diyl)-bis(oxy))bis(4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane) modified rhodium complexes molecularly adsorbed onto porous silica powder show surprisingly high activity and regioselectivity in the gas-phase hydroformylation of propene to butanal, with no sign of deactivation. Operando IR investigations combined with density functional theory calculations confirm a side reaction: the aldol condensation of the butanal products. These heavier by-products accumulate inside the pores of the catalytic material. IR and gas chromatography show a direct relation between formation of enones, products of the aldol condensation, performance, and stability of the catalytic system. This demonstrates that the aldol condensation products generated in situ act as a solvent providing an ideal environment to the impregnated homogeneous catalyst.
Electrochemical Reduction of Carbon Dioxide to 1-Butanol on Oxide-Derived Copper
Chen, Stuart Tze-Jin,García-Muelas, Rodrigo,López, Núria,Martín, Antonio J.,Pérez-Ramírez, Javier,Pablo-García, Sergio,Peng, Yujie,Per, Edwin Yu Xuan,Ting, Louisa Rui Lin,Veenstra, Florentine L. P.,Yeo, Boon Siang
, p. 21072 - 21079 (2020)
The electroreduction of carbon dioxide using renewable electricity is an appealing strategy for the sustainable synthesis of chemicals and fuels. Extensive research has focused on the production of ethylene, ethanol and n-propanol, but more complex C4 molecules have been scarcely reported. Herein, we report the first direct electroreduction of CO2 to 1-butanol in alkaline electrolyte on Cu gas diffusion electrodes (Faradaic efficiency=0.056 %, j1-Butanol=?0.080 mA cm?2 at ?0.48 V vs. RHE) and elucidate its formation mechanism. Electrolysis of possible molecular intermediates, coupled with density functional theory, led us to propose that CO2 first electroreduces to acetaldehyde-a key C2 intermediate to 1-butanol. Acetaldehyde then undergoes a base-catalyzed aldol condensation to give crotonaldehyde via electrochemical promotion by the catalyst surface. Crotonaldehyde is subsequently electroreduced to butanal, and then to 1-butanol. In a broad context, our results point to the relevance of coupling chemical and electrochemical processes for the synthesis of higher molecular weight products from CO2.
Effect of Sodium Cation Addition on the Hydroformylation of Propene over Silica-supported Group VIII Metal Catalysts
Naito, Shuichi,Tanimoto, Mitsutoshi
, p. 1403 - 1404 (1989)
Addition of a sodium cation to silica-supported Rh, Pd, Pt, and Ni catalysts markedly lowers the activation energy of the hydroformylation process without affecting the regioselectivity of the products and facilitates the CO insertion into propyl intermediates.
Mechanistic study of ethanol dehydrogenation over silica-supported silver
Sushkevich, Vitaly L.,Ivanova, Irina I.,Taarning, Esben
, p. 2367 - 2373 (2013)
A silica-supported Ag catalyst has been shown to be an efficient heterogeneous catalyst for the oxidant-free dehydrogenation of ethanol into acetaldehyde. The reaction mechanism has been investigated by insitu FTIR spectroscopy. The kinetic isotope effects for proton and hydride abstraction have been studied by using CH3CD2OH and CH3CH2OD as labeled reactants. The results indicate that O-H bond activation and the formation of a hydrogen-bonded complex take place on the silica support and that the Ag particles are necessary for the activation of the C-H bond. The kinetic isotope effect (kH/kD) is 1.9 for CH3CD2OH and 1.8 for CH3CH2OD. The concerted mechanism of C-H cleavage on the Ag sites and proton abstraction on the silica sites is proposed to account for the results of the spectroscopic and kinetic experiments.
Kinetics and Mechanism of the Oxidation of Butane-2,3-Diol by Alkaline Hexacyanoferrate (III), Catalyzed by Ruthenium Trichloride
Balado, A. Mucientes,Jimenez, F. Santiago,Martin, F. J. Poblete,Castellanos, R. Varon
, p. 1 - 8 (1997)
The kinetics of oxidation of butane-2,3-diol by alkaline hexacyanoferrate (III), catalyzed by ruthenium trichloride has been studied spectrophotometrically.The reaction rate shows a zero-order dependence on oxidant, a first-order dependence on T, a Michaelis-Menten dependence on , and a variation complicated on ->.A reaction mechanism involving the existence of two active especies of catalyst, Ru(OH)2+ and Ru(OH)3, is proposed.Each one of the active species of catalyst forms an intermediate complex with the substrate, which disproportionates in the rate determining step.The complex disproportionation involves a hydrogen atom transfer from the α-C-H of alcohol to the oxygen of hydroxo ligand of ruthenium, to give Ru(II) and an intermediate radical which is then further oxidized.
An FT IR Study of the Isomerization and O2 Reaction of n-Butoxy Radicals
Niki, H.,Maker, P. D.,Savage, C. M.,Breitenbach, L. P.
, p. 2698 - 2700 (1981)
Using the long path FT IR method, we made product studies of the photolysis of n-butyl nitrite (n-C4H9ONO) in ppm concentrations at 700 torr of air and 298 +/- 2 K.Unidentified HO-containing compounds as well as n-butyraldehyde (n-C3H7CHO) were detected.The results provide further evidence for the occurence of the following competitive uni- and bimolecular reaction paths for the ensuing n-butoxy radicals: intramolecular hydrogen-shift isomerization CH3CH2CH2CH2O. -> CH2CH2CH2CH2OH (1), and O2 reaction CH3CH2CH2CH2O. + O2 -> CH3CH2CH2CHO + HO2 (2).From the observed yield of n-C3H7CHO, the relative rate k2/k1 has been determined to be 0.23 +/- 0.03 (2?) at 700 torr of air.
Hydroformylation of propene heterogeneously catalyzed by HRh(CO)(PPh 3)3 encapsulated in to hexagonal mesoporous silica - Parametric variation and mass transfer study
Sudheesh,Parmar, Jaydeep N.,Shukla, Ram S.
, p. 124 - 131 (2012)
An in situ encapsulated HRh(CO)(PPh3)3 in to the pores of hexagonal mesoporous silica (HMS) acting as nanophase reactors, was investigated for the catalytic hydroformylation of propene. The encapsulated catalyst (Rh-HMS) was synthesized and characterized by PXRD, FT-IR, surface area measurements and TEM. The catalyst was effectively active with 99% conversion of propene and 100% selectivity to aldehydes. The effects of reaction parameters: temperature, partial pressure of CO and H2, amount of catalyst and HRh(CO)(PPh3)3 to TEOS ratio on conversion, selectivity and rates were investigated in detail. The rates determined in term of the formation of aldehydes were found to be first order with respect to hydrogen pressure. Catalyst showed first order dependence towards its lower amount. CO pressure variation showed positive order towards lower pressure and inhibition at higher pressures. The investigated mass transfer effects on the kinetics indicated that the reaction runs with negligible mass transfer limitations. The heterogenized Rh-HMS catalyst was effectively recycled for six times.
Palladium-Catalyzed Oxidative N-Dealkylation/Carbonylation of Tertiary Amines with Alkynes to α,β-Alkynylamides
Mane, Rajendra S.,Bhanage, Bhalchandra M.
, p. 4974 - 4980 (2016)
The first highly effective Pd/C-catalyzed oxidative N-dealkylation/carbonylation of various aliphatic as well as cyclic tertiary amines with alkynes has been described. The selective sp3 C-N bond activation of tertiary amines at the less steric side using O2 as a sole oxidant and a plausible reaction pathway for the reaction are discussed. The general and operationally simple methodology provides an alternative for the synthesis of a wide range of alk-2-ynamide derivatives under mild conditions. The present protocol is ecofriendly and practical, and it shows significant recyclability.
Two new fatty acid derivatives from the stem bark of alchornea laxiflora (euphorbiaceae)
Sandjo, Louis Pergaud,Poumale, Hervé M. Poumale,Siwe, Xavier Noudou,Ntede, Hippolyte Nga,Shiono, Yoshihito,Ngadjui, Bonaventure Tchaleu,Krause, Rui M. W.,Ndinteh, Derek Tantoh,Mbafor, Joseph Tanyi
, p. 1153 - 1159 (2011)
Euphorbiaceae is a family of plants used in traditional remedies in central Africa to treat selected diseases. Some of the phytochemical components in the stem bark of Alchornea laxiflora that have biochemical activity were identified. A number of novel compounds were isolated, including a new fatty acid ester, (1) a new ceramide, (2) some triterpenoids, (3-5), ellagic acid (6) and its derivatives (7, 8) were isolated. The structures of these compounds were determined on the basis of spectroscopic methods as well as HR-ESI-TOF-MS analysis, chemical transformation and by comparison of their physical and spectral data with those reported in the literature. The cytotoxicity of some isolated compounds was investigated against human promyelocytic leukaemia (HL60) cell line by using the MTT method. Compounds 1, 4 and 5 showed a cytotoxic activity with IC50 at 58.7, 6.6 and 6.8 μM, respectively.
Copper(I) complexes with polymeric 2,2′-biquinoline-containing ligands as electrocatalysts for selective oxidation of the secondary hydroxy group in 3,24-dihydroxy-5β-cholane with oxygen
Magdesieva,Dolganov,Latyshev,Yakimanskii,Goikhman,Podeshvo,Lukashev
, p. 62 - 65 (2011)
Indirect electrocatalytic selective oxidation of the secondary hydroxy group in 3,24-dihydroxy-5β-cholane was performed using atmospheric oxygen in the presence of copper(I) complex with a polymeric 2,2′-biquinoline- containing ligand as catalyst. The reaction was characterized by a high yield (85%), 100% selectivity, and mild conditions, the CuII/CuI redox potential being -0.55 V relative to Ag/AgCl/KCl.
