Kinetic studies on the homogeneous hydrogenation of fumaric and maleic acid catalysed by bis(dimethylglyoximato)cobalt(II)

1984 ◽  
Vol 93 (2) ◽  
pp. 73-81
Author(s):  
S. Vasanthkumar ◽  
S. Vancheesan ◽  
J. Rajaram ◽  
J. C. Kuriacose
Keyword(s):  
Maleic Acid ◽  
Kinetic Studies ◽  
Homogeneous Hydrogenation

KINETIC STUDIES OF CHLORO COMPLEXES OF RHODIUM AS HYDROGENATION CATALYSTS

1966 ◽  
Vol 44 (2) ◽  
pp. 233-242 ◽  
Author(s):  
B. R. James ◽  
G. L. Rempel
Keyword(s):  
Maleic Acid ◽  
Kinetic Studies ◽  
Homogeneous Catalyst ◽  
Ferric Ion ◽  
Homogeneous Hydrogenation ◽  
Acid Complex ◽  
Olefinic Bond ◽  
Hydrogenation Catalysts ◽  
Chloro Complexes ◽  
Anionic Complexes

The anionic complexes [RhCl6]3−, [Rh(H2O)Cl5]2−, and [Rh(H2O)2Cl4]− activate molecular hydrogen for the reduction of ferric ion in aqueous acid solution; the catalytic activity increased with increasing number of chloride ligands present. Cationic and neutral chloroaquorhodium(III) complexes did not homogeneously catalyze the reduction of ferric ion, the complexes themselves being reduced to metallic rhodium, a powerful heterogeneous catalyst.Chloro complexes of rhodium(III) and rhodium(I) were not effective catalysts in aqueous solution for the homogeneous hydrogenation of the olefinic bond in maleic acid. Anionic chlororhodate(III) complexes were reduced by hydrogen to the univalent state, this state being stabilized against further reduction to the metal by complexing with the maleic acid present. Preliminary studies indicate that in dimethylacetamide solution rhodium (III) trichloride is an effective homogeneous catalyst for the reduction of maleic acid to succinic acid by hydrogen, the reaction proceeding through a rhodium (I) – maleic acid complex.

Homogeneous Hydrogenation of Unsaturated Carboxylic Acids Using Chlororhodate(I) Complexes and Rhodium(I) Diethylsulfide Complexes

1975 ◽  
Vol 53 (6) ◽  
pp. 797-804 ◽  
Author(s):  
Brian R. James ◽  
Flora T. T. Ng
Keyword(s):  
Carboxylic Acids ◽  
Rate Constants ◽  
Maleic Acid ◽  
Activation Parameters ◽  
Kinetic Studies ◽  
Homogeneous Hydrogenation ◽  
Chloride Solutions ◽  
Rate Determining Step ◽  
Square Planar ◽  
Unsaturated Carboxylic Acids

N,N-Dimethylacetamide solutions of the cyclooctene complex [Rh(C8H14)2Cl]2, in the presence of excess chloride or diethylsulfide, are effective for the homogeneous hydrogénation of unsaturated carboxylic acids at ca. 80 °C and 1 atm H2. Kinetic studies on the hydrogenation of maleic acid are consistent with a rate determining step involving oxidative addition of H2 to square planar rhodium(I) olefin species. Rate constants and activation parameters agree with those determined previously from similar studies using corresponding rhodium(III) complexes and give confirmation that rhodium(I) catalysts are involved in the rhodium(III) systems. Discussion of the systems is limited by the somewhat uncertain nature of the catalysts; however, chlororhodate(I) species are involved in the chloride solutions, and bis(diethylsulfide) complexes appear likely in the sulfide systems.

Kinetic Studies on the Conformational Transition of the Copolymer of Styrene and Maleic Acid in Aqueous Salt Solution

1974 ◽  
Vol 7 (6) ◽  
pp. 961-963 ◽  
Author(s):  
Shintaro Sugai ◽  
Nobumichi Ohno ◽  
Katsutoshi Nitta
Keyword(s):  
Salt Solution ◽  
Maleic Acid ◽  
Conformational Transition ◽  
Kinetic Studies ◽  
Aqueous Salt Solution

Flavin radicals, conformational sampling and robust design principles in interprotein electron transfer: the trimethylamine dehydrogenase-electron-transferring flavoprotein complex

2004 ◽  
Vol 71 ◽  
pp. 1-14
Author(s):  
David Leys ◽  
Jaswir Basran ◽  
François Talfournier ◽  
Kamaldeep K. Chohan ◽  
Andrew W. Munro ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Kinetic Studies ◽  
Molecular Assembly ◽  
Conformational Sampling ◽  
Trimethylamine Dehydrogenase ◽  
Key Residues ◽  
Electron Transferring Flavoprotein ◽  
Electron Transfer Complex

TMADH (trimethylamine dehydrogenase) is a complex iron-sulphur flavoprotein that forms a soluble electron-transfer complex with ETF (electron-transferring flavoprotein). The mechanism of electron transfer between TMADH and ETF has been studied using stopped-flow kinetic and mutagenesis methods, and more recently by X-ray crystallography. Potentiometric methods have also been used to identify key residues involved in the stabilization of the flavin radical semiquinone species in ETF. These studies have demonstrated a key role for 'conformational sampling' in the electron-transfer complex, facilitated by two-site contact of ETF with TMADH. Exploration of three-dimensional space in the complex allows the FAD of ETF to find conformations compatible with enhanced electronic coupling with the 4Fe-4S centre of TMADH. This mechanism of electron transfer provides for a more robust and accessible design principle for interprotein electron transfer compared with simpler models that invoke the collision of redox partners followed by electron transfer. The structure of the TMADH-ETF complex confirms the role of key residues in electron transfer and molecular assembly, originally suggested from detailed kinetic studies in wild-type and mutant complexes, and from molecular modelling.

2-methylpentane catalytic reactions on Pt(3%wt)-HNaβ-zeolite. Kinetic studies

1998 ◽  
Vol 95 (3) ◽  
pp. 536-560 ◽  
Author(s):  
S. Siffert ◽  
F. Garin
Keyword(s):  
Kinetic Studies ◽  
Catalytic Reactions
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