Showing papers on "Noble metal published in 1974"

Noble metal catalysis. III. Preparation of dialkyl oxalates by oxidative carbonylation

Abstract: Die Synthese von Diathyloxalat (IV) in Alkoholen unter Zusatz von Edelmetallkatalysatoren und Oxidationsmitteln wird untersucht.

High superconducting transition temperatures in the palladium-noble metal-hydrogen system

Abstract: High superconducting transition temperatures, Tc, of 16.6, 15.6 and 13.6 K have been observed in Pd-(Cu, Ag and Au) alloys, charged with large amounts of H by means of ion implantation at liquid Helium-temperatures. A peculiar phase-transition indicates that weak phonon modes might be responsible for the high Tc-values. The difference between the maximum Tc-values can be described as a type of isotope effect Tc∞M−1/2.

Determination of the noble metals in geological materials by neutron activation analysis

Abstract: Gold, ruthenium, palladium, osmium, iridium, and platinum were determined in geological materials using thermal neutron irradiation, selective adsorption of the noble metal group on Srafion NMRR ion exchange resin, and high- resolution gamma spectrometry. The method was used to analyze three USGS standard rocks, a meteorite, and a lunar soil sample. (auth)

Dry plasma process for etching noble metal

Abstract: There is disclosed a process for etching noble metals, particularly for removing selected areas of thin films of electrically conductive noble metals, by contacting exposed areas of noble metal with a plasma that must include both fluorine and chlorine and may, optionally, also contain oxygen.

Steam Reforming of Hydrocarbons on Noble Metal Catalysts (Part 1)

Abstract: The catalytic activity of Group VIII transition metals except Os for methanesteam reaction under atmospheric pressure at 350∼600°C was investigated. The following activity sequence was obtained: Ru∼Rh>Ni>Ir>Pd∼Pt>>Co∼Fe.Ru and Rh were found to possess high and stable activity over a wide range of steam/methane ratio. The rate of reaction on a Rh-silica catalyst was found to be of the zeroth and 0.5th order with respect to methane and steam, respectively.

Metal recovery method

Abstract: The present invention is a method of treating sea or land carbonaceous ore or reconstituted, formerly carbonaceous ore to recover therefrom noble metal values. If sea ore is used, noble metal containing composite organic material is first separated from any shells or sand that may be present. Flotation techniques are then utilized to form a carbonaceous concentrate, which is next mixed with a strong oxidizing agent. The mixture may either be heated to provide autogenously ignition or ignition may alternatively be accomplished by compounding the mixture into electrodes and using electric arc. If stoichiometric quantities of the oxidizing agent are used, the oxidation-reduction reaction, which consumes all carbon present, is of sufficient energy to drive the noble metals and/or their compounds into the vapor phase forming a particulate plasma, from which the elemental metals or their compounds may be condensed and/or precipitated. If non-stoichiometric quantities of oxidant are used, recovery of the sought metals may be had from the ash by techniques well known to those skilled in the art.

Method of fabricating a carbon - polytetrafluoroethylene electrode - support

Abstract: An electrode substrate is described which is suitable for supporting noble metal electrodes in fuel cells and similar electrochemical cells It is composed of fine graphite particles enmeshed in a web of fibers of polytetrafluoroethylene (PTFE) produced by forming a homogeneous mixture of graphite particles and PTFE powder in an organic liquid, removing the liquid, and milling the mixture in a series of steps to form a thin, porous, electrically conductive sheet of graphite-PTFE which is an excellent support for thin film metallic electrodes and which is resistant to corrosive electrolytes

Resins for separating heavy metals consisting of thiourea-group-containing macroporous vinyl aromatic crosslinked matrixes

Abstract: The invention concerns new, crosslinked, macroporous, vinyl-aromatic plastic materials containing thiourea groups, to processes for their production and to their use for adsorbing metal compounds, especially noble metal and mercury compounds.

Stabilized automotive exhaust gas catalyst

Abstract: A process for preparing an ultra stable catalyst capable of converting the noxious components in exhaust gases to innocuous entities is described. The catalyst is made by applying a solution of a salt of a noble metal such as palladium or platinum to a specially prepared support followed by activation at 1,800 DEG -2,100 DEG F. The special support is prepared by activating and stabilizing common support materials such as alumina with cerium oxide at high temperatures prior to application of the noble metal. The catalyst is stable to 2,100 DEG F.

Method of cleaning air containing carbon monoxide

Abstract: Polluted air containing carbon monoxide can be cleaned by passing at ambient temperature the polluted air, firstly through a filter for adsorbing materials capable of reducing at ambient temperature the oxidation activity of a noble metal catalyst and then through a catalyst layer, which is composed of the noble metal catalyst supported by active carbon and contains 20 to 50% by weight of water based on the weight of total weight of the noble metal catalyst and the active carbon.

Process for recovering noble metal

Abstract: A process for recovering a Group VIII noble metal with a high yield from an organic solvent solution containing a soluble complex of the noble metal and an organophosphorus compound comprising burning the organic solvent solution in a combustion zone, introducing the combustion product immediately into the aqueous absorbing solution to catch in the aqueous solution the particles of the noble metal and phosphorus oxide formed in the combustion, and recovering the noble metal particles from the aqueous solution.

Hydrogenation of coal

Abstract: The invention relates to the hydrogenation of coal which comprises extracting the coal with a solvent at temperatures and pressures above the critical temperature and pressure of the solvent in the presence of hydrogen and an effective amount of catalyst comprising a salt or oxide of a metal which is not a noble metal and which is liquid or solid at the extraction temperature. The gas phase solvent may then be separated from the solid residue and the hydrogenated products condensed therefrom by cooling.

Hydrocarbon conversion processes utilizing rejuvenated zeolite catalysts

Abstract: Siliceous zeolite catalysts comprising zeolitic mono- and/or divalent metal cations and a non-zeolitic Group VIII noble metal hydrogenating component supported thereon, which catalysts have undergone damage by thermal and/or hydrothermal stresses resulting in a maldistribution of the metal components, are rejuvenated in activity by a first treatment with a volumetric excess of aqueous ammonium hydroxide, followed by a second treatment with an extractive proportion of an aqueous ammonium salt solution. The combined treatments have a twofold effect of bringing about a desirable redistribution of the Group VIII noble metal, and of exchanging out at least a portion of undesired zeolitic mono- and/or divalent metal ions. A highly advantageous procedure for carrying out the rejuvenation involves simply neutralizing the ammonium hydroxide-catalyst mixture from the first treatment with a suitable acid to give the ammonium salt desired for the second treatment. Hydrocarbon conversion processes utilizing the rejuvenated catalysts are also disclosed.

Process for redispersion of noble metal catalysts using fluorine

Abstract: This invention relates to the treatment of Group VIII, noble metal, catalysts, wherein said noble metal is present on a refractory support and where said noble metal exists as large agglomerated crystallites, e.g., greater than 50 A, which comprises contacting said catalyst with fluorine at a temperature and for a time sufficient to disperse said crystallites to crystallites having substantially smaller particle size. The noble metals which may be dispersed by this process include Pt, Pd, Ru, Ir and Rh. This invention is especially suitable for redispersing iridium-containing catalysts. In a preferred embodiment of the instant invention, an iridium containing reforming catalyst which has become at least partially deactivated because of the presence of carbonaceous deposits is regenerated by contacting, serially, (1) with an oxygen-containing gas at a temperature and for a time sufficient to substantially remove said carbonaceous deposits (2) with hydrogen at a temperature and for a time sufficient to convert said iridium substantially to its metallic form, and (3) with a fluorine-containing gas at a temperature of less than 300°C. for a time sufficient to yield a catalyst wherein the iridium is present in crystallites of relatively small average particle size, e.g., less than 50 A.

Virtual bound states in dilute transition metal and noble metal based disordered alloys

Abstract: The virtual bound d-density of states arising from small concentrations of d resonant impurities in transition metal and noble metal based disordered alloys is calculated, using a slightly modified version of the theory of Riedinger. With this information, the changes in specific heat, residual resistivity, thermoelectric power and optical absorption on alloying, may be obtained. The d component of the local density of states is given. From this follows the degree of localization of the impurity charge and the impurity contribution to the soft X-ray L amd M emission spectra. Results are presented for CuNi, CuCo and CuFe alloys and compared with known experimental values.

Process for preparing ferromagnetic alloy powder

Abstract: A process for preparing a ferromagnetic alloy powder comprising reducing salts of ferromagnetic metals in an aqueous solution containing an acicular fine powder in the presence of hypophosphite ion is disclosed. The aqueous solution can be subjected to the action of a magnetic field or ultrasonic waves during the reaction if desired, and the rate of the reaction can be increased by the addition to the aqueous solution of a noble metal ion.

Metal, particularly gold, recovery from adsorbed cyanide complexes

Abstract: The invention provides a method of recovering transition or noble metal values, particularly gold and silver values, from a support having absorbed thereon the metal values in the form of an ionic complex, particularly a cyanide ionic complex, by desorbing the metal values with water of low cation concentration such as deionized or softened water. When the cation of the complex is an alkaline earth metal cation then the support is preferably subjected to a pre-treatment with an alkali metal salt solution to effect an exchange reaction before the desorption step.

Catalyst for hydrogenation and dehydrogenation of hydrocarbons

Abstract: A novel catalytic composite comprising a Group VIII noble metal component, an alkalinous metal component and a Group VII-B metal component, having an atomic number greater than 25, on an alumina carrier is utilized in the hydrogenation of aromatic hydrocarbons to the corresponding cycloparaffins and in the dehydrogenation of normal paraffins to the corresponding mono-olefins. With respect to the former, there is negligible yield loss to both gaseous waste material and to acyclic hydrocarbons as a result of ringopening; in the latter, there is afforded a significant decrease in the quantity of non-normal hydrocarbons in the product stream. The particularly preferred catalytic composite comprises a platinum or palladium component, a lithium or potassium component and a rhenium component.

Method of making a semi-permeable, essentially water-insoluble, hydrophilic nylon membrane and resultant product

Abstract: There is described the preparation of hydrophilic, semi-permeable film membranes having an increase in pores and containing complex-forming metals. The films can be formed from solutions having film-forming material and pore-forming material dissolved in a solvent. The films can be useful for separating a component, e.g. an aliphatically-unsaturated hydrocarbon, from mixtures by the combined use of liquid barrier permeation and metal complexing techniques. The liquid barrier is at least partially within the hydrophilic film membrane during use, and the barrier contains complex-forming metal ions in aqueous solution. The metal ions may be, for example, noble metal, nickel, mercurous, cuprous or other metal ions, and mixtures of these metal ions, and the aqueous solution may contain other cations. The separation of ethylene from ethane and methane is of particular interest.

Cobalt-manganese titanate noble metal combination catalysts

Abstract: Noble metal-containing cobalt-manganese titanate catalysts active for carbon monoxide and hydrocarbon oxidation and the use of these catalysts in catalytic devices for the treatment of combustion exhaust gases such as automotive exhaust gases are described

Process for the recovery of noble metals

Abstract: A process for the recovery of noble metals emanating from the surface of catalysts used in high pressure gas reactions involving absorbing the noble metal dispersed in the reaction gas in an intercepting bed formed of acid-soluble metal oxides in which the external boundary surface of the intercepting bed is 1.5 to 20 times the cross-sectional area of the catalyst bed surface, the thickness of the intercepting bed, in the direction of gas flow through the material thereof, is 20 to 40 mm., and the flow of the reaction gases in the intercepting bed is in a direction parallel to the plane of the supporting base of the bed.

Process for the manufacture of unsaturated esters of carboxylic acids

Abstract: of the Disclosure Unsaturated esters of carboxylic acids are prepared by reacting olefins or cycloolefines with carboxylic acids and oxygen in the gaseous phase in the presence of a catalyst containing noble metal salts or noble metals of the VIIIth group of the Periodic System and alcali metal salts and/or alcaline earth metal salts, as activators the content of noble metal being in the range of from 1.2 to 5% by weight and the proportion of the metal fraction of each individual activator to the noble metal content being in the range of from 0.5 to 1 to 3 : 1.