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Platinum addition initiated

Tlie effect of platinum on the trap and in the fuel, in absence of any other additive, is significant. The minimum temperature is approximately 75 K lower as a result of the platinum. If the platinum additive is used in combination with an untreated EX80 filter the balance point decreases from an initial 750 K to 675 K after several days, provided that the temperature in the filter has been occasionally high, for example during regenerations. If the temperature in the filter was kept low, the filter was less active. [Pg.358]

Platinum electrodes do not give products continuously in CO2 reduction in aqueous media under 1 atm as shown in Table 3. Platinum electrodes initially reduce CO2 to reduced 002 . The entity of the reduced CO2 is CO strongly adsorbed on the Pt electrode, as revealed by Beden et al. by means of infrared spectroscopy. Tills fact is later confirmed by other workers. " In addition to linearly bonded CO as the major adsorbed species, small amounts of bridged and multibonded CO, COH and HCOO species are also detected on Pt electrode surface. The presence of reduced CO2 on Pt electrode practically inhibits further reduction of CO2 in aqueous media. The formation of reduced CO2 proceeds as below in the potential region in which adsorbed hydrogen is stably present. [Pg.144]

Copland, E. (2005) Thermodynamic Effect of Platinum Additions to -NiAl An Initial Investigation, NASA/CR-2005-21330. Cleveland, OH NASA. [Pg.1178]

Co-ordination of monoalkenes to complexes of the type [PdQifacXallyl)] occurs rapidly and reversibly in solution at room temperature. However, the introduction of strain into the alkene promotes a ready insertion of the alkene into allyl-palladium and -platinum bonds. Initial rapid and reversible formation of [Pd(hfac)(rate-determining step again involving migration of a (7-allylic group from palladium to the co-ordinated alkene via a concerted cis-exo addition of Pd—C across the double bond. [Pg.333]

Examples of perfluoroalkyl iodide addition to the triple bond include free radical addition of perfluoropropyl iodide to 1 -heptyne [28] (equation 21), thermal and free radical-initiated addition of lodoperfluoroalkanesulfonyl fluorides to acetylene [29] (equation 22), thermal addition of perfluoropropyl iodide to hexa-fluoro 2 butyne [30] (equation 23), and palladium-catalyzed addition of per-fluorobutyl iodide to phenylacetylene [31] (equation 24) The E isomers predominate in these reactions Photochemical addition of tnfluoromethyl iodide to vinylacetylene gives predominantly the 1 4 adduct by addition to the double bond [32] Platinum catalyzed addition of perfluorooctyl iodide to l-hexyne in the presence of potassium carbonate, carbon monoxide, and ethanol gives ethyl () per fluorooctyl-a-butylpropenoate [JJ] (equation 25)... [Pg.763]

Substantially more work has been done on reactions of square-planar nickel, palladium, and platinum alkyl and aryl complexes with isocyanides. A communication by Otsuka et al. (108) described the initial work in this area. These workers carried out oxidative addition reactions with Ni(CNBu )4 and with [Pd(CNBu )2] (. In a reaction of the latter compound with methyl iodide the complex, Pd(CNBu )2(CH3)I, stable as a solid but unstable in solution, was obtained. This complex when dissolved in toluene proceeds through an intermediate believed to be dimeric, which then reacts with an additional ligand L (CNBu or PPh3) to give PdL(CNBu )- C(CH3)=NBu I [Eq. (7)]. [Pg.31]

Subsequent to the initial report by Badley et al. two communications appeared, which reported structural investigations on several products obtained from PtCl4 , methyl isocyanide, and hydrazine 33, 117) these compounds had previously been identified (incorrectly) as six-coordinate platinum(II) species 90). In addition, synthesis work in this area was extended somewhat further by these groups. The details of this work presented in these communications and in later full papers 34, 117) are summarized hy Eqs. (17). [Pg.43]

Since the initial report on the addition reactions of palladium(II) and platinum(II) isocyanide complexes by Badley et al. (S), a rather substantial number of further examples have been reported. These are summarized in Table II. [Pg.45]

AXB) shows time courees of amounts of evolved hydrogen and decalin conversions with caibon-supported platinum-based catalysts unda" supeiheated liquid-film conditions. Enhancement of dehydrogenation activities for decalin was realized by using fiiese composite catalysts. The Pt-W / C composite catalyst exhibited the hipest reaction rate at the initial stage, whereas the Pt-Re / C composite catalyst showed the second highest reaction rate in addition to low in sensitivity to retardation due to naphthaloie adsorbed on catalytic active sites [1-5], as indicated in Fig. 2(A) ). [Pg.179]

The additivity principle was well obeyed on adding the voltammograms of the two redox couples involved even though the initially reduced platinum surface had become covered by a small number of underpotential-deposited mercury monolayers. With an initially anodized platinum disk the catalytic rates were much smaller, although the decrease was less if the Hg(I) solution had been added to the reaction vessel before the Ce(lV) solution. The reason was partial reduction by Hg(l) of the ox-ide/hydroxide layer, so partly converting the surface to the reduced state on which catalysis was greater. [Pg.8]

Scheme 5-10 Radical-initiated (Eq. 1) and platinum-catalyzed (Eq. 2) addition of PH3 to ethyl acrylate... Scheme 5-10 Radical-initiated (Eq. 1) and platinum-catalyzed (Eq. 2) addition of PH3 to ethyl acrylate...
Anderson and Kemball (35) examined the reaction between gaseous deuterium and benzene catalyzed by evaporated films of iron, nickel, palladium, silver, tungsten, and platinum. The order of reactivity (estimated from the temperature at which the addition reaction achieved an initial rate of 1% per minute for a 10 mg film at certain specified reactant... [Pg.135]

Initially we tried the standard approach, reduction of NiL, NiB, or NiC with 2.0 equivalents of potassium in refluxing THF. Finely divided black nickel powders were obtained however, they showed rather limited reactivity toward oxidative addition with carbon-halogen bonds. Similar results were found for palladium and platinum. [Pg.230]

Intermolecular bis-silylation of unactivated alkenes has been achieved initially with a zerovalent platinum catalyst such as Pt(PPh3)4 (Equations (30) and (31)).101 1,2-Difluorotetramethyldisilane undergoes addition to ethylene and norbornene in the presence of Pt(PPh3)4 catalyst at 150 °G to give the corresponding adducts in 95% and 26% yields, respectively. For the addition of 1,2-diphenyltetramethyldisilane to ethylene, Pt(PMe3)4 (33% yield) was found to be more active than Pt(PPh3)4 (4% yield). [Pg.738]

Kubica et al45 also investigated the effect of platinum-modified zeolites on the decalin reaction. They found that the addition of Pt enhances the catalyst activity. The initial isomerization was increased 3 times, which can be interpreted in terms of a change in the reaction initiation. In addition to initiation by a PC step over Bronsted acid sites, as proposed for H-form zeolites, a bifunctional initiation path... [Pg.49]


See other pages where Platinum addition initiated is mentioned: [Pg.63]    [Pg.336]    [Pg.77]    [Pg.55]    [Pg.158]    [Pg.32]    [Pg.6]    [Pg.11]    [Pg.41]    [Pg.39]    [Pg.216]    [Pg.41]    [Pg.178]    [Pg.57]    [Pg.108]    [Pg.53]    [Pg.347]    [Pg.121]    [Pg.705]    [Pg.32]    [Pg.115]    [Pg.251]    [Pg.383]    [Pg.444]    [Pg.451]    [Pg.462]    [Pg.201]    [Pg.248]    [Pg.306]    [Pg.255]    [Pg.254]    [Pg.186]    [Pg.225]    [Pg.66]   


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Initial addition

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