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Platinum hydrogenation

Figure 7.3 Plot of the platinum (hydrogen plus anion) charge density versus the charge density associated with the adatom redox process (Bi or Te, as indicated) on a Pt(l 11) electrode in 0.5 M H2SO4 solution. Straight lines represent the expected behavior for the stoichiometry indicated in the figure. Figure 7.3 Plot of the platinum (hydrogen plus anion) charge density versus the charge density associated with the adatom redox process (Bi or Te, as indicated) on a Pt(l 11) electrode in 0.5 M H2SO4 solution. Straight lines represent the expected behavior for the stoichiometry indicated in the figure.
Hydrosilylation turned out to be a unique method in organosilicone chemistry, but in some cases it suffers from severe side reactions. An explanation is provided by the generally accepted reaction mechanism known as "Chalk-Harrod mechanism" described elsewhere [7]. Included in this series of reaction steps is an insertion of olefmic ligands into a platinum-hydrogen bond. Since the metal may be bonded to either of the unsaturated carbon atoms and the reaction is also an equilibrium, alkenes may result which are in fact isomerized starting material. Isomeric silanes are to be expected as well (Eq. 1), along with 1-hexylsilane, which is by far, the main compound produced. [Pg.254]

An interesting correlation exists between the work function of a metal and its pzc in a particular solvent. Consider a metal M at the pzc in contact with a solution of an inert, nonadsorbing electrolyte containing a standard platinum/hydrogen reference electrode. We connect a platinum wire (label I) to the metal, and label the platinum reference electrode with II. This setup is very similar to that considered in Section 2.4, but this time the metal-solution interface is not in electronic equilibrium. The derivation is simplified if we assume that the two platinum wires have the same work function, so that their surface potentials are equal. The electrode potential is then ... [Pg.29]

Chiral-Modified Platinum Hydrogenation Catalysts and Related Systems.510... [Pg.493]

The use of equation (3.2) to study the behaviour of catalysts is known as solid electrolyte potentiometry (SEP). Wagner38 was the first to put forward the idea of using SEP to study catalysts under working conditions. Vayenas and Saltsburg were the first to apply the technique to the fundamental study of a catalytic reaction for the case of the oxidation of sulfur dioxide.39 Since then the technique has been widely used, with particular success in the study of periodic and oscillatory phenomena for such reactions as the oxidation of carbon monoxide on platinum, hydrogen on nickel, ethylene on platinum and propylene oxide on silver. [Pg.14]

In the infrared (IR) spectrum the v(Pl H) of the terminal platinum hydrogen stretching vibration appears as a sharp band of medium intensity at 2160 cm-1. The v(Pl D) band of the corresponding deuteride occurs at 1580 cm-1. [Pg.137]

The inefficiency of the platinum/hydrogen reduction system and the dangers involved with the combination of molecular oxygen and molecular hydrogen led to a search for alternatives for the reduction of the manganese porphyrin. It was, for example, found that a rhodium complex in combination with formate ions could be used as a reductant and, at the same time, as a phase-transfer catalyst in a biphasic system, with the formate ions dissolved in the aqueous layer and the manganese porphyrin and the alkene substrate in the organic layer [28]. [Pg.154]

Abstract The primary method for pH is based on the measurement of the potential difference of an electrochemical cell containing a platinum hydrogen electrode and a silver/silver chloride reference electrode, often called a Harned cell. Assumptions must be made to relate the operation of this cell to the thermodynamic definition of pH. National metrology institutes use the primary method to assign pH values to a limited number of primary standards (PS). The required comparability of pH can be ensured only if the buffers used for the calibration of pH meter-electrode assemblies are traceable to... [Pg.206]

The primary method for pH is based on the measurement of the potential difference of the electrochemical cell without a liquid junction involving a selected buffer solution, a platinum hydrogen gas electrode and a silver/silver chloride reference electrode, often also referred to as a Harned cell. [Pg.207]

Secondary pH reference materials can be derived from the PS buffer solutions by different measurement procedures, which provide results for pH(SS) of the same nominal composition as pH(PS) pH(SS) of different composition pH(SS) not compatible with platinum hydrogen electrodes. [Pg.210]

To achieve highest metrological quality, it is strongly recommended to derive SSs from PSs of nominally the same chemical composition. Liquid junction potentials are largely minimised when buffer solutions of nominally the same chemical composition are separated from one another in a strictly isothermal cell (II) containing two platinum hydrogen cells at exactly the same hydrogen pressure [19]. [Pg.210]

Use of a catalyst that is in a separate phase from the reactants. For example, a platinum hydrogenation catalyst is a solid, a separate phase from the liquid alkene. (p. 356)... [Pg.384]

Ruthenium and rhodium are more susceptible to inhibition by hydrogen halides than are platinum and palladium. Under mild conditions ruthenium is inhibited even by acetic acid, which is generally a good solvent for hydrogenations over rhodium, palladium, and platinum. Hydrogen chloride may become an inhibitor for rhodium-catalyzed hydrogenations. Freifelder has shown that hydrochloric acid is a strong in-... [Pg.54]

In the preliminary stages of this study, some difficulty was experienced in obtaining stable potentials with the silver-silver chloride electrode in H20/NMA mixtures at a mole fraction of NMA of 0.5. However, the emf of cells with platinized platinum-hydrogen electrodes and silver-silver bromide electrodes reached values which were constant over a period of at least 4 to 5 hr, making this cell appear suitable for a study of the thermodynamics of HBr in H20/NMA mixtures with mole fraction NMA (x2) up to at least 0.50. [Pg.254]

Reduction. Kornbium found that reduction of (—)-2-nitrooctane to the amine by iron and acetic acid proceeds with at least 82% retention of optical purity. Platinum hydrogenation in acetic acid was somewhat less satisfactory, and platinum hydrogenation in absolute ethanol led to 90% racemization. Reduction with L1AIH4 was attended with complete racemization. [Pg.993]

The reduction of cis- and frrw.s-l,4,4a,6,7,8,9,lla-octahydropyrido[2,l-h]quinazolin-l 1-one with platinum/hydrogen has also been described39. [Pg.906]


See other pages where Platinum hydrogenation is mentioned: [Pg.560]    [Pg.160]    [Pg.510]    [Pg.6]    [Pg.18]    [Pg.357]    [Pg.97]    [Pg.31]    [Pg.530]    [Pg.222]    [Pg.188]    [Pg.29]    [Pg.392]    [Pg.312]    [Pg.81]    [Pg.264]    [Pg.339]    [Pg.74]    [Pg.250]    [Pg.231]    [Pg.530]    [Pg.24]    [Pg.168]    [Pg.560]    [Pg.71]   
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See also in sourсe #XX -- [ Pg.8 , Pg.418 ]

See also in sourсe #XX -- [ Pg.281 , Pg.352 ]

See also in sourсe #XX -- [ Pg.8 , Pg.418 ]

See also in sourсe #XX -- [ Pg.505 ]




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1,3-Butadiene, hydrogenation over platinum

Catalytic hydrogenation sodium borohydride/platinum

Five-coordinate platinum complexes hydrogen bonds

Hydrogen Adsorption on Binary Platinum Metal Alloys

Hydrogen Evolution on Platinum

Hydrogen absorption into platinum

Hydrogen adsorbed on platinum

Hydrogen adsorbed platinum

Hydrogen adsorption on platinum

Hydrogen dissociation on platinum

Hydrogen evolution reaction platinum

Hydrogen peroxide reaction with platinum

Hydrogen peroxide, addition platinum complexes

Hydrogen platinum

Hydrogen platinum

Hydrogen platinum catalyst

Hydrogen thermal desorption, platinum

Hydrogen, adsorption, platinum metal

Hydrogen, adsorption, platinum metal reduction

Hydrogen, on platinum

Hydrogen-platinum bond, polarization

Hydrogen/deuterium reaction with platinum

Hydrogenation over Platinum

Hydrogenation over platinum catalyst

Hydrogenation palladium/platinum catalyst

Hydrogenation platinum complexes

Hydrogenation platinum hydride complexes

Hydrogenation, apparatus for highpressure over platinum

Hydrogenation, of a double bond over platinum

Hydrogenations Using Platinum

Oxidation of hydrogen on platinum

Platinum Catalyst Poisoning by Traces of Co in the Hydrogen

Platinum aldehyde hydrogenation

Platinum black, hydrogenation catalyst

Platinum catalysis hydrogenation

Platinum catalyst hydrogen overvoltage

Platinum catalyst hydrogen-oxygen reaction

Platinum catalyst, hydrogen adsorptivity

Platinum catalysts supported, hydrogen chemisorption

Platinum colloidal, hydrogenation catalyst

Platinum complexes hydrogen-deuterium exchange

Platinum dioxide, hydrogenation

Platinum dioxide, hydrogenation catalyst

Platinum electrocatalytic hydrogenation

Platinum electrode hydrogen adsorption

Platinum for hydrogen

Platinum hydrogen abstraction

Platinum hydrogen adsorption

Platinum hydrogen bonding interactions

Platinum hydrogen cell

Platinum hydrogen dissociation

Platinum hydrogen electrode

Platinum hydrogen reaction

Platinum hydrogenation of pyridines

Platinum in hydrogenation

Platinum in photoproduction of hydrogen from water

Platinum ketone hydrogenation

Platinum oxide hydrogenation catalyst

Platinum oxides in photoproduction of hydrogen from water

Platinum powders, hydrogen

Platinum reaction with hydrogen

Platinum sponge, hydrogenation catalyst

Platinum spontaneous hydrogen reaction

Platinum, and hydrogenation

Platinum, asymmetric hydrogenations

Platinum-iridium clusters hydrogen

Platinum-rhenium catalysts hydrogen

Platinum-rhodium oxide, hydrogenation

Platinum-rhodium oxide, hydrogenation aromatic rings

Platinum-rhodium oxide, hydrogenation ketones

Platinum-silica hydrogenation, olefins

Platinum/zeolite hydrogenation, selective

Platinum: hydrogenation catalyst

Reduction hydrogenation over platinum

Surface Structure on Hydrogen Adsorption at Platinum

The Hydrogen-Evolution Reaction on Platinum

The adsorption of hydrogen on platinum

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