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Carbon on platinum

Another important potential appHcation for fuel cells is in transportation (qv). Buses and cars powered by fuel cells or fuel cell—battery hybrids are being developed in North America and in Europe to meet 2ero-emission legislation introduced in California. The most promising type of fuel cell for this appHcation is the SPEC, which uses platinum-on-carbon electrodes attached to a soHd polymeric electrolyte. [Pg.173]

Du Pont uses a Hquid-phase hydrogenation process that employs a palladium —platinum-on-carbon catalyst. The process uses a plug-flow reactor that achieves essentially quantitative yields, and the product exiting the reactor is virtually free of nitroben2ene. [Pg.231]

Hydroxylamines ordinarily do not accumulate in the reduction of aromatic nitro compounds for, with some exceptions, most systems in competition will reduce the hydroxylamine function preferentially. Nonetheless, systems have been found that afford the intermediate aromatic hydroxylamine in excellent yield. With hydrogen gas as a reductant and platinum-on-carbon or -on-alumina and about I wt % of DMSO based on nitro compound as a modifier, aromatic hydroxylamines can be formed in 90% yield under mild conditions. The reduction slows markedly after absorption of the second mole of hydrogen and should be stopped at this stage (80). [Pg.106]

Phenylhydroxylamine rearranges in sulfuric acid to give mainly p-aminophenol. Industrial routes to this compound have been developed in which phenylhydroxylamine, formed by hydrogenation of nitrobenzene in sulfuric acid over platinum-on-carbon, is rearranged as it is formed. Conditions are adjusted so that the rate of rearran ment is high relative to the rate of hydrogenation of hydroxylamine to aniline (15,17,86). An easy way to obtain a favorable rate ratio is to carry out the reduction with about 1% DMSO present in the sulfuric acid (79,81). [Pg.107]

The platinum concentrations in the platinized carbon blacks are reported to be between 10 and 40% (by mass), sometimes even higher. At low concentrations the specific surface area of the platinum on carbon is as high as lOOm /g, whereas unsupported disperse platinum has surface areas not higher than 10 to 15m /g. However, at low platinum concentrations, thicker catalyst layers must be applied, which makes reactant transport to reaction sites more difficult. The degree of dispersion and catalytic activity of the platinum depend not only on its concentration on the carrier but also on the chemical or electrochemical method used to deposit it. [Pg.365]

GustavssonM, Fredriksson H, Kasemo B, Jusys Z, Jun C, Behm RJ. 2004. Nanostructured platinum-on-carbon model electrocatalysts prepared by colloidal lithography. J Electroanal Chem 568 371-377. [Pg.457]

Introducing Engelhard s New, Low-Dispersed, Edge-Coated, Platinum-on-Carbon Powder Catalysts, Engelhard New Product Bulletin, 2001. [Pg.122]

Ignition occurred when methanol was charged into an unpurged autoclave containing platinum-on-carbon catalyst. [Pg.1894]

The original patent uses platinum as the catalyst and calls for temperatures of 100-300° and pressures of 45-115 psi(47). We found that such rigorous conditions are not required for the hydrosilation reaction with most commercial sources of platinum on carbon. Usually vigorous stirring at slightly elevated temperatures, 40-80°, at 15 psi will give moderate yields of the product. The rates and yields are usually highly dependent on the method of preparation of the catalyst. However, ultrasound permits the reaction to occur at a useful rate at 30° at atmospheric pressure(48) ... [Pg.221]

Platinum on carbon did almost exactly the same thing but required a temperature of about 100°C to do so. With excess acetylene, only III formed. With tcrt-butylacetylene no II formed, probably because of steric hindrance, but I and III formed readily. 3-Hexyne reacted more slowly, required heat with chloroplatinic acid, and formed exclusively c/s-3-di-chlorosilyl-3-hexene. Trichlorosilane with platinum on carbon also added (57) to 1-alkynes or to phenylacetylene exclusively by cis addition to give only trans adducts. Later works (55) indicate that chloroplatinic acid and other soluble catalysts also give exclusively cis addition with a wide variety of Si—H compounds. [Pg.444]

The first metallic catalyst used for dehydrocyclization of alkanes (/) was platinum on carbon (10-40 w/w% metal). It is typically used around atmospheric pressure and temperatures not exceeding 300°C. Such catalysts are inadequate for praetical purposes. This is the reason for commercial dual-function catalysts—typically platinum on silica-alumina—having been developed 32). [Pg.278]

C5 Cyclization of various alkanes 38, 38a) over platinum on carbon was first observed in 1954. Barron et al. 15a) postulated the formation of a surface C5 cyclic intermediate, which may desorb as a cyclopentanic hydrocarbon or may produce skeletal isomers without desorption. [Pg.292]

Kazansky et al. reported (over platinum on carbon under identical conditions) about 5% C5 cyclic yield from -alkanes 38), 12% from 3-ethylpentane (79), and 35% from 2,2,4-trimethylpentane 38a, 80). The Cj cyclization of 2,5-dimethylhexane did not take place, presumably because the end methyl group removes carbon atom No. 2 from the surface 81) (Scheme VII). The... [Pg.295]

Catalyst 15% platinum on carbon T = 320°C flow system, space velocity, 0.2 hr (for hydrocarbon, no space velocity is given for hydrogen). Analysis data are related to liquid products. [Pg.310]

Kazansky et al. (5) estimated the role of C5 cyclic intermediates in aromatization to be about 5% over platinum on carbon. Dautzenberg and Platteeuw found about 11% C5 cyclic pathway with nonacidic platinum on alumina (23). 2,2,4-Trimethylpentane is forced to produce aromatics via C5 cyclization because of its structure here the quaternary carbon atom facilitates ring enlargement (5, 23). [Pg.315]

Although the above reactions are written in terms of the global species, no specific mention has been made about how the reaction proceeds. For example, each reaction can be broken down into single electron-transfer reactions, and the gas probably dissolves into the membrane that is covering the electrocatalyst sites (e.g., platinum on carbon). Some more comments about this can be found in section 4.4. Adding eqs 1 and 2 yields the overall reaction... [Pg.447]

The kinetic expressions result in transfer currents that relate the potentials and currents in the electrode (platinum on carbon) and electrolyte (membrane) phases as well as govern the consumption and production of reactants and products. To simplily the equations and approaches for the case of one ionically and one electronically conducting phase, it is useful to use the relation... [Pg.463]

The monosubstituted double bond in 4-vinylcyclohexene is hydrogenated over P-1 nickel in preference to the disubstituted double bond in the ring, giving 98% of 4-ethylcyclohexane [73]. Similarly in limonene the double bond in the side chain is reduced while the double bond in the ring is left intact if the compound is treated with hydrogen over 5% platinum on carbon at 60° and 3.7 atm (yield 97.6%) [348]. [Pg.42]

Selective reduction of the nitrile group in 87% yield without the reduction of the carbonyl was achieved by stannous chloride [1153]. Oximes of keto nitriles are reduced preferentially at the oximino group by catalytic hydrogenation in acetic anhydride over 5% platinum on carbon (yield 85%)... [Pg.175]

According to the figure below, reacting 2,6-dimethylanilme with the acid chloride of pyridine-carboxylic acid first gives the 2,6-xylidide of a-picoUnic acid (2.2.4). Then the aromatic pyridine ring is reduced to piperidine by hydrogen in the presence of a platinum on carbon catalyst. [Pg.15]

The resulting 2,6-xylidide a-pipecolinic acid (2.2.5) is methylated to mepivacaine using formaldehyde with simultaneous reduction by hydrogen in the presence of platinum on carbon catalyst [15]. [Pg.15]

Phenylpropanolamine Phenylpropanolamine, D,L-erythro-1 -phenyl-2-methylamino-propanol-1 (11.3.7), is synthesized from propiophenone by nitrosation into an isonitroso derivative (11.3.6). Reduction of this by hydrogen in hydrochloric acid while simultaneously using two catalysts, palladium on carbon and platinum on carbon, gives norephedrine (11.3.7) [56-59]. [Pg.157]

Labetalol Labetalol, 2-hydroxy-5-[l-hydroxy-2-[(l-methyl-3-phenylpropanol)amino)] ethyl] benzamide (12.1.12) is synthesized by the WaUcylation of iV-benzyl-Af(4-phenyl-2-butyl)amine 5-bromacetylsalicylamide and forming aminoketone (12.1.11), which is further debenzylated by hydrogen using a palladium-platinum on carbon catalyst into labetalol (12.1.12) [28-30]. [Pg.166]

Methylfluorene has been prepared by cleavage of ethyl 9-methyl-9-fluorenylglyoxylate,4 by the decarboxylation of 9-methylfluorene-9-carboxylic acid,4 by the decarboxylation of 9-fluorenylacetic acid,6 by the cleavage of 9-methyl-9-acetyl-fluorene with alcoholic potassium hydroxide or soda-lime,6 by the reduction of 9-methyl-9-fluorenol with hydriodic acid in acetic acid,7 by the reaction of 9-fluorenyllithium 8 or -sodium 9 with methyl iodide or methyl sulfate,9 by the cyclization of diphenylmethyl carbinol over platinum-on-carbon at 300°,10 by the reaction of ethyl 9-methoxymcthyl-9-fluorcnylcarboxylate,11 by the diazotization and heating of 2-ethyl-2-aminobiphenyl,12 by the dehydration and then reduction of 9-mcthyl-9-fluorcnol,13... [Pg.45]

The following commercial powder catalysts (all from Degussa) were used in the screening runs rhodium-platinum oxide (45,65% Rh, 19,8% Pt), rhodium oxide (58,2% Rh), platinum oxide (80,6% Pt), palladium-on-carbon (5% Pd) and platinum-on-carbon (5% Pt). [Pg.210]

Dibutylamine, piperidine, N-ethylcyclohexylamine, N-ethyldicyclohexylamine, and the ketones were reagent grade chemicals. The 5% palladium on carbon, 5% platinum on carbon, sulfided 5% platinum on carbon and sulfided 5% rhodium on carbon catalysts were obtained from Engelhard Industries. The 20% molybdenum sulfide on alumina (Girdler T-318) was obtained from the Chemetron Corp. Palladium chloride was obtained from Matheson, Coleman and Bell. Ruthenium trichloride was obtained from Ventron. [Pg.353]


See other pages where Carbon on platinum is mentioned: [Pg.36]    [Pg.97]    [Pg.570]    [Pg.444]    [Pg.87]    [Pg.291]    [Pg.295]    [Pg.317]    [Pg.321]    [Pg.295]    [Pg.306]    [Pg.312]    [Pg.313]    [Pg.10]    [Pg.39]    [Pg.119]    [Pg.74]    [Pg.537]    [Pg.36]    [Pg.354]    [Pg.355]   
See also in sourсe #XX -- [ Pg.275 ]

See also in sourсe #XX -- [ Pg.982 ]




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Carbon monoxide on platinum

Carbon monoxide on platinum metals

Carbon monoxide oxidation, on platinum

Metal catalysts platinum-on-carbon

On platinum

Platinum carbon

Platinum on activated carbon

Platinum on carbon black

Platinum on carbon catalysts

Platinum sulfide-on-carbon

The oxidation of carbon monoxide on platinum

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