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Hydrogen kinetics

Hydrogen kinetic acidity ol thiazolium ions and thiazole has received much attention since Breslow (419,420) and Ingraham and Westheimer... [Pg.113]

See also Biofuels Capital Investment Decisions Hydrogen Kinetic Energy, Historical Evolution of the Use of Methanol Natural Gas, Processing and Conversion of. [Pg.69]

J.-P. Mikkola, R. Sjoholm, T. Salmi and P. Maki-Arvela, Xylose hydrogenation kinetic and NMR studies of the reaction mechanisms. Catalysis Today 48 (1999) 73. [Pg.116]

German ED, Kuznetsov AM (1981) Dependence of the hydrogen kinetic isotope effect on the reaction free energy. J Chem Soc, Faraday Trans 1 77 397—412... [Pg.265]

The pyridine-catalysed lead tetraacetate oxidation of benzyl alcohols shows a first-order dependence in Pb(OAc)4, pyridine and benzyl alcohol concentration. An even larger primary hydrogen kinetic isotope effect of 5.26 and a Hammett p value of —1.7 led Baneijee and Shanker187 to propose that benzaldehyde is formed by the two concurrent pathways shown in Schemes 40 and 41. Scheme 40 describes the hydride transfer mechanism consistent with the negative p value. In the slow step of the reaction, labilization of the Pb—O bond resulting from the coordination of pyridine occurs as the Ca—H bond is broken. The loss of Pb(OAc)2 completes the reaction with transfer of +OAc to an anion. [Pg.836]

These reactions proceed through symmetrical transition states [H H H] and with rate constants kn,HH and kH,DH, respectively. The ratio of rate constants, kH,HH/kH,DH> defines a primary hydrogen kinetic isotope effect. More precisely it should be regarded as a primary deuterium kinetic isotope effect because for hydrogen there is also the possibility of a tritium isotope effect. The term primary indicates that bonds at the site of isotopic substitution the isotopic atom are being made or broken in the course of reaction. Within the limits of TST such isotope effects are typically in the range of 4 to 8 (i.e. 4 < kH,HH/kH,DH < 8). [Pg.314]

Secondary hydrogen kinetic isotope effects are further classified as alpha, beta, etc. depending on the distance of the isotopically substituted atom from the bond(s) that is (are) being made or broken (a = 1 bond, 3 = 2 bonds, etc.). Consider the simple Sn2 reaction between hypochlorite anion and ethyl chloride ... [Pg.320]

J. Wang, A.D. Ebner, T. Prozorov, R. Zidan, J.A. Ritter, Effect of graphite as a co-dopant on the dehydrogenation and hydrogenation kinetics of Ti-doped sodium aluminum hydride , J. Alloys Compd. 395 (2005) 252-262. [Pg.284]

A more detailed description of the use of a pseudo-elementary step for the treatment of hydrogenation kinetic data and derivatization of the kinetic equations can be found elsewhere [30-32]. [Pg.377]

This zinc metalloenzyme [EC 1.1.1.1 and EC 1.1.1.2] catalyzes the reversible oxidation of a broad spectrum of alcohol substrates and reduction of aldehyde substrates, usually with NAD+ as a coenzyme. The yeast and horse liver enzymes are probably the most extensively characterized oxidoreductases with respect to the reaction mechanism. Only one of two zinc ions is catalytically important, and the general mechanistic properties of the yeast and liver enzymes are similar, but not identical. Alcohol dehydrogenase can be regarded as a model enzyme system for the exploration of hydrogen kinetic isotope effects. [Pg.43]

It was shown that the AB5/ABS composite tolerated the hydrogenation effects on metal particles, with no losses in hydrogenation kinetics. The results indicated that the compositions are suitable for metal hydride based hydrogen storage devices. [Pg.243]

Because electron-spectroscopic and ion-scattering methods yield information about the first seven atom layers, applying these techniques to metal-hydrogen kinetic problems requires incorporating depth-profiling capability. That is, an argon-sputtering gun must be incorporated into the analysis system to remove undesired surface material up to several nanometers deep. [Pg.390]

In general, the use of Langmuir-Hinshelwood-Hougen-Watson (LHHW)-type of rate equation for representing the hydrogenation kinetics of industrial feedstocks is complicated, and there are too many coefficients that are difficult to determine. Therefore, simple power law models have been used by most researchers to fit kinetic data and to obtain kinetic parameters. [Pg.441]

These findings do not support the suggestion by Thomson and Webb (241) that the similarities in hydrogenation kinetic parameters during catalysis by a wide range of different transition metals could be understood if the reaction involved the participation of similar hydrocarbon residues in all cases. On the other hand, it is clear that at higher hydrocarbon/H2 ratios, relatively unreactive hydrocarbon species (mostly ethylidyne) do indeed accumulate on the surface in all cases. [Pg.71]

Unusually large hydrogen kinetic isotope effects might, therefore, be better regarded in the first instance as diagnostic of a mechanism involving a transient intermediate, and the simplest case is illustrated in Scheme 9.18. Application of the steady-state assumption to the intermediate I yields the expressions shown for the pseudo-first-order rate constants for disappearance of the reactant R (kR) and formation of products PA and PB (kpA and kPB). The expressions for the kinetic isotope effects for formation of each product (superscripts L and H refer to light and heavy isotopes) are also shown. [Pg.255]

Mukhopadhyay, S., Rothenberg, G., Wiener, H. and Sasson, Y. (1999) Palladium-catalyzed aryl-aryl coupling in water using molecular hydrogen kinetics and process optimization of a solid-liquid-gas system. Tetrahedron, 55, 14, 763. [Pg.36]

Fig. 4. Rectification plot for isobutane dehydrogenation and isobutylene hydrogenation kinetic data over Pt/Sn/Si02. Adapted from (38). Fig. 4. Rectification plot for isobutane dehydrogenation and isobutylene hydrogenation kinetic data over Pt/Sn/Si02. Adapted from (38).
Table IV is a concise summary of the effect of the number of aromatic rings and their configurational arrangement on the hydrogenation kinetics of relevant polynuclear... Table IV is a concise summary of the effect of the number of aromatic rings and their configurational arrangement on the hydrogenation kinetics of relevant polynuclear...
Table IV. Summary of the effect of the number and configurational arrangement of aromatic rings on the hydrogenation kinetics of aromatic model compounds (54)... Table IV. Summary of the effect of the number and configurational arrangement of aromatic rings on the hydrogenation kinetics of aromatic model compounds (54)...
Abstract. The alloys with low grain sizes were determined to have the best hydrogenation kinetics. The additives of intermetallide La(Mm)Ni5 were found to enhance the rate of hydrogen uptake and to decrease the temperature of dehydrogenation. [Pg.341]

Keywords Alloy Composite Hydrogen Intermetallide Ternary eutectic Hydrogenation kinetics Mechanochemical treatment Hydrogen sorption... [Pg.341]


See other pages where Hydrogen kinetics is mentioned: [Pg.107]    [Pg.108]    [Pg.130]    [Pg.383]    [Pg.386]    [Pg.822]    [Pg.565]    [Pg.1590]    [Pg.322]    [Pg.375]    [Pg.379]    [Pg.379]    [Pg.383]    [Pg.476]    [Pg.25]    [Pg.28]    [Pg.590]    [Pg.385]    [Pg.1082]    [Pg.194]    [Pg.201]    [Pg.328]    [Pg.284]    [Pg.285]   
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See also in sourсe #XX -- [ Pg.115 ]

See also in sourсe #XX -- [ Pg.302 , Pg.303 ]

See also in sourсe #XX -- [ Pg.115 ]

See also in sourсe #XX -- [ Pg.302 , Pg.303 ]

See also in sourсe #XX -- [ Pg.139 , Pg.145 ]




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Aldehydes hydrogenation kinetics

Alkali-hydrogen exchange kinetics

Asymmetric hydrogenation kinetic studies

Catalytic kinetic resolution and directed hydrogenation

Cyclohexene hydrogenation kinetics

Desorption kinetics, hydrogen/silicon

Disordered proteins hydrogen exchange kinetics

Dynamic kinetic asymmetric hydrogenation

Dynamic kinetic resolution asymmetric transfer hydrogenation

Dynamic kinetic resolution hydrogenation

Electrochemical behaviour of hydrogen peroxide oxidation kinetics and mechanisms

Ethene, hydrogenation kinetics

Heterogeneous Electron Transfer Kinetics at Hydrogen- Versus Oxygen-Terminated Electrodes

Histidine hydrogen exchange kinetics

Hydrogen Langmuir-Hinshelwood kinetics

Hydrogen Peroxide Dissociation Kinetics and the Mechanism

Hydrogen Sorption Kinetics

Hydrogen absorption kinetics

Hydrogen atom abstraction atomic transfer kinetics

Hydrogen atom kinetic energy

Hydrogen bond breaking kinetics

Hydrogen bonds transfer kinetics

Hydrogen desorption kinetics

Hydrogen evolution reaction kinetics

Hydrogen exchange kinetics

Hydrogen exchange mixed) kinetics

Hydrogen kinetic curves

Hydrogen kinetic isotope effect studie

Hydrogen kinetic isotope effects

Hydrogen kinetic parameters

Hydrogen kinetic properties

Hydrogen oxidation kinetics

Hydrogen oxidation reaction kinetic activity

Hydrogen permeation kinetics

Hydrogen peroxide decomposition chemical kinetics

Hydrogen reduction kinetics

Hydrogen structures atomic transfer kinetics

Hydrogen sulfide kinetics parameters

Hydrogen-deuterium kinetic isotope effect

Hydrogen-tritium kinetic isotope effects

Hydrogen/deuterium reaction with kinetic isotope effect

Hydrogenation catalysis kinetics

Hydrogenation kinetic equations, substrate concentration

Hydrogenation kinetic parameters

Hydrogenation kinetic resolution

Hydrogenation kinetic results

Hydrogenation kinetics

Hydrogenation kinetics

Hydrogenation kinetics, liquid phase

Hydrogenation reactions kinetics

Hydrogenation/dehydrogenation kinetics

Hydrogen—deuterium kinetic data

Kinetic Analysis of Peptide-Averaged Hydrogen Exchange

Kinetic Isotope Effect for Metals with High Hydrogen Overpotentials

Kinetic Parameters of the Hydrogen Oxidation Reaction

Kinetic heterogeneously catalyzed hydrogenation

Kinetic isotope effect hydrogen isotopes

Kinetic isotope effects carbon-hydrogen insertions

Kinetic isotope effects hydrogen shifts

Kinetic isotope effects primary hydrogen-deuterium

Kinetic isotope effects secondary alpha hydrogen-deuterium

Kinetic isotope effects secondary hydrogen-deuterium

Kinetic parameters hydrogen electrode process

Kinetic studies of substituent effects in electrophilic aromatic hydrogen exchange

Kinetically Significant Hydrogen

Kinetics and thermodynamics of hydrogenation reactions

Kinetics hydrogen activation energy

Kinetics of Aromatic Ring Hydrogenation

Kinetics of CO hydrogenation

Kinetics of Catalytic Hydrogenations in the Liquid Phase

Kinetics of Hydrogen Exchange in Disordered Proteins

Kinetics of Hydrogenation

Kinetics of hydrogen

Kinetics of hydrogen evolution

Kinetics of the Hydrogen Oxidation Reaction

Kinetics phenol hydrogenation

Kinetics, hydrogen peroxide-sulfur

Kinetics, hydrogen peroxide-sulfur reaction

Olefins hydrogenation kinetics

Primary kinetic hydrogen isotope effects

Ru-catalyzed hydrogenation of racemic 2-substituted aldehydes via dynamic kinetic resolution

Surface kinetics, effect upon hydrogen

Temperature dependence hydrogen atom transfer kinetics

Toluene, hydrogenation kinetic parameters

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