Showing papers on "Noble metal published in 1971"

Area Relationships in Galvanic Corrosion

Abstract: The effect of variations of the area of two metals in a galvanic couple is discussed for three common cases. In Case 1, it is assumed that the only significant process on the more active metal (A) at the galvanic potential (ϕg) is metal oxidation (dissolution), while the only significant process on the more noble metal (C) is reduction of the oxidizer (H+, H2O, O2) and Tafel behavior is observed. Various possibilities to present the galvanic current as a function of electrode areas, which might have lead to some confusion in the literature, are discussed. In Case 2, it is assumed that metal (A), the anode in the galvanic couple, is polarized only slightly from its corrosion potential. It is shown that in this case the galvanic current density (igA) is not equal to the dissolution rate (idA) of the anode. A correlation between these two values is given. In Case 3, it is assumed that the cathodic process on both metals is entirely diffusion controlled. In this case, the dissolution rate of the anod...

Process for the production of catalysts for making vinyl esters

Abstract: HIGHLY ACITIVE CATALYSTS FOR THE PREPARATION OF CATALYSTS SUITABLE FOR VINYL ESTER, E.G., VINYL ACETATE, PRODUCTION ARE PREPARED BY TREATING A CATALYST SUPPORT, SIMULTANIOUSLY OR IN EITHER SEQUENCE, WITH OR WITHOUT INTERMEDIATE DRYING, WITH: (A) A SOLUTON OF NOBLE METALS CONTAINING AT LEAST SALTS OF PALLADIUM AND GOLD, AND (B) A SOLUTION CONTAINING COMPOUNDS, E.G., GASES SUCH AS SODIUM HYDROXIDE, WHICH ARE ABLE TO REACT WITH THE NOBLE METAL SALTS OF THE SOLUTION (A) TO FORM WATER INSOLUBLE NOBLE METAL COMPOUNDS; IMPREGNATING THE CATALYST SUPPORT WITH SUCH QUANTITIES OF SOLUTIONS (A) AND (B) CORRESPONDING TO FROM 10 TO 110% OF THE ABSORPTIVE CAPACITY OF THE CATALYST SUPPORT FOR THESE SOLUTIONS; SUBJECTING THE IMPREGNATED CATALYST SUPPORT TO A TIME TEMPERATURE TREATMENT SUCH THAT AT LEAST 95% OF THE IMPREGNATED PALLADIUM AND GOLD ARE TRANSFORMED INTO WATER INSOLUBLE NOBLE METAL COMPOUNDS; REDUCING THE METAL COMPOUNDS TO THE NOBLE METAL WITH A REDUCING AGENT, E.G., ETHYLENE OR HYDRAZINE; REMOVING THE WATER-SOLUBLE COMPOUNDS WHICH ARE CONTAINED IN THE CATALYST BY WASHING BEFORE OR AFTER THE REDUCTION STEP; AND OPTIONALLY TREATING THE RESULTING CATALYST WITH AN ALKALI METAL CARBOXYLATE, E.G., ACETATE, BEFORE OR AFTER THE TREATMENT WITH THE REDUCING AGENT.

Noble metal determination in meteorites.

Abstract: gefunden werden, wie bei der Wismutmetall-Fällung beobachtet wird. Dennoch steht das Ergebnis im Einklang mit qualitativen Angaben von 0 . H A H N , L. M E I T N E B und F. STRASSMANN [ 3 ] , denn im Filtrat ist das Eka-Rhenium bevorzugt vorzufinden. Auch die übrigen Ergebnisse dieser Autoren werden voll bestätigt. Das Verhalten der Spaltprodukte bei den Trennversuchen, ermittelt anhand charakteristischer y-Piks, geht aus Tab. 4 hervor. Die Anund Abreicherung der Elemente entspricht weitgehend dem erwarteten Verhalten, wenn man berücksichtigt, daß die Spaltprodukte trägerfrei vorlagen. Sie erklärt aber auch qualitativ die Anund Abreicherung des „Eka-Rheniums\" gegenüber dem „Eka-Osmium\" bei denselben Trennversuchen, Tab. 3. Berücksichtigt man nämlich, daß laut Tab. 2 das 16min „Eka-Rhenium\" hauptsächlich aus Molybdän-, Technetiumund Antimon-Isotopen, das 59-min „Eka-Osmium\" hingegen hauptsächlich aus Tellurund Jodisotopen besteht, so wird sowohl die starke Anreicherung der 16-min Komponente im Nitronperrhenat als auch ihr Fehlen im Rheniumsulfid und an der Platin-Wasserstoffelektrode klar. Ebenso wird verständlich, daß die Fällung von Wismutmetall und von Hydroxiden keine so starke Fraktionierung ergab, denn hier verhalten sich die Hauptbestandteile jener beiden „Transurane\" verschiedenartig. Mehr als ein solcher qualitativer Vergleich dürfte nicht angebracht sein, denn es erscheint durchaus möglich, daß zur /?-Aktivität verschiedener, in Tab. 3 erfaßter Fraktionen Spaltprodukte beitrugen, die bei den γspektrometrischen Analysen der Tab. 4 nicht berücksichtigt wurden.

Polymerization of ethylene with a supported palladium catalyst

Abstract: HYDROCARBON OLEFINS ARE CONVERTED TO HIGHER BOILING PRODUCTS COMPRISING POLYMERS AND OLIGOMERS OF THE OLEFIN AND ALKYLATES OF THE OLEFIN WITH PARAFFINIC HYDROCARBONS IN THE PRESENCE OF A GROUP VIII NOBLE METAL DISTENDED ON A SYNTHETIC ZEOLITE, I.E., AN ALUMINOSILICATE MOLECULAR SIEVE, THAT HAS BEEN PRETREATED WITH HYDROGEN AT CONDITIONS TO IMPART SELECTIVE POLYMERIZATION OR ALKYLATION ACTIVITY THERTO. IN A SPECIFIC EMBODIMENT, ETHYLENE IS POLYMERIZED TO LOW BOILING OLIGOMERS COMPRISING DIMERS, TRIMERS, TETRAMERS, ETC. BY CONTACTING THE ETHYLENE UNDER POLYMERIZATION CONDITIONS WITH A PALLADIUM CATALYST PREPARED BY IMPREGNATION OF A PALLADIUM SALT OR ION EXCHANGE OF PALLADIUM FROM A PALLADIUM SALT ONTO A Y MOLECULAR SIEVE THAT HAS BEEN PRETREATED WITH HYDROGEN AT A TEMPERATURE FROM ABOUT 200* TO 900*F. OR IS POLYMERIZED TO SOLID POLYMER WHEN THE HYDROGEN TREATMENT IS PERFORMED AT A TEMPERATURE FROM 0* TO 100*F. THE ETHYLENE IS ALSO REACTED UNDER ALKYLATION CONDITIONS WITH A PARAFFIN HYDROCARBON BY CONTACTING THE OLEFIN AND PARAFFIN UNDER ALKYLATION CONDITIONS WITH A PALLADIUM DEPOSITED ON A Y MOLECULAR SIEVE THAT HAS PRETREATED BY CONTACTING WITH HYDROGEN AT A TEMPERATURE OF FROM 100* TO ABOUT 200*F.

Chelated metal-polyphosphoric acid catalysts,method of preparation and isomerization process utilizing the same

Abstract: NOVEL CATALYSTS ARE PREPARED BY CHELATING IONS OF A GROUP VIII NOBLE METAL, E.G., PLATINUM, WITH A POLYPHOSPHORIC ACID AND DEPOSITING THE CHELATE ON A POROUS SUPPORT. THE CATALYST IS ESPECIALLY USEFUL FOR ISOMERIZING HYDROCARBONS.

Electrolytic cell including titanium hydride cathodes and noble-metal coated titanium hydride anodes

Abstract: Electrolytic cells for the electrolysis of aqueous alkali metal chlorides are disclosed. Further disclosed are electrodes for use in combination with said cells, the said electrodes having titanium hydride cathodic members and noble metal coated titanium hydride anodic members. The noble metal coatings on the anodic members are gold, silver, platinum, palladium, iridium, ruthenium, osmium, and rhodium. In one exemplification, the electrolytic cell is of bipolar configuration and has a bipolar electrode of titanium hydride with a titanium hydride cathodic surface, and a noble metal anodic surface.

Silver image stabilization with noble metal compounds and alpha,beta-enediol developer

Abstract: THE PRESENT INVENTION RELATES TO A NOVEL PHOTOGRAPHIC FILM UNIT ADAPTED TO PROVIDE SILVER IMAGES OF ENHANCED IMAGE STABILITY WHICH COMPRISES PHOTOSENSITIVE SILVER HALIDE, A NOBLE METAL COMPOUND CONTAINING A NOBLE METAL ION BELOW SILVER IN THE ELECTROMOTIVE FORCE SERIES OF ELEMENTS, AND A SILVER HALIDE DEVELOPING AGENT WHOSE OXIDATION PRRODUCT IS SUBSTANTIALLY NONOXIDATIVE TO THE THUS-FORMED SILVER IMAGE FOR A TIME SUFFICIENT TO ENABLE THE NOBLE METAL ION TO CONTACT SAID SILVER IMAGE TO PROVIDE SUSTAINED AND LONG-LASTING STABILIZATION EFFECTS.

Purification of terephthalic acid

Abstract: A PROCESS FOR PURIFYING TEREPHTHALIC ACID (OBTAINED FROM CRUDE TEREPHTHALIC ACID AND CONTAINING SMALL AMOUNTS OF 4-CARBOXYBENZALDEHYDE AND OTHER IMPURITIES BY A REDUCTIVE TREATMENY OF AN AQUEOUS SOLUTION WHICH CONTAINS FROM 5 TO 45% BY WEIGHT KOF FROMIC ACID AT ACID AND FROM 0.0003 TO 3% BY WEIGHT OF FORMIC ACID AT ELEVAED TEMPERATURE AND IN THE PRESENCE OF A NOBLE METAL CATALYST OF THE EIGHT GROUP OF THE PERIODIC TABLE. THE AQUEOUS MIXTURE IS HEATED TO A TEMPERATURE OF AT LEAST 230*C.

Dehydrogenation process over platinum on lithiated mordenite

Abstract: Normal alkanes containing from six to 16 carbon atoms are selectively dehydrogenated to mono-alkenes and side reactions are minimized by contacting a hydrocarbon feedstock with a noble metal catalyst supported on a lithiated synthetic mordenite in the presence of hydrogen under appropriate dehydrogenation conditions.

Reforming catalyst and preparation

Abstract: HYDRATED ALUMINA GEL, HAVING A SMALL AMOUNT OF GROUP V-B METAL OXIDE UNIFORMLY DISTRIBUTED THEREIN, IS CALCINED, LEACHED WITH ACETIC ACID, RECALCINED, HUMIDIFIED, AND IMPREGNATED WITH A GROUP VIII NOBLE-METAL-CONTAINING COMPOSITION. REDUCTIVE TREATMENT OF SUCH MATERIAL TO PROVIDE SUPPORTED METALLIC GROUP VIII NOBLE METAL RESULTS IN HIGHLY ACTIVE, STABLE, HARD REFORMING CATALYST HAVING VERY LOW BULK DENSITY.

Preparation of carbon supported promoted noble metal catalysts

Abstract: CARBON SUPPORTED PROMOTED NOBLE METAL CATALYSTS HAVING INCREASED ACTIVITY MAY BE PREPARED BY ADDING A BASIC COMPOUND TO A SLURRY OF A SOLUBLE NOBLE METAL COMPOUND, A SOLUBLE METALLIC PROMOTER AT A HIGH VALENCY STATE AAND PARTICULATE CARBON TO DEPOSIT A NOBLE METAL COMPOUND AND A HIGH VALENCY METALLIC PROMOTER ONTO THE PARTICULATE CARBON AND THEN CO-REDUCING THE NOBLE METAL COMPOUND TO A METALLIC FORM AND THE HIGH VALENCY METALLIC PROMOTER TO A LOW VALENCY METALLIC PROMOTER

Hydrogenation of polystyrene

Abstract: A PROCESS FOR THE HYDROGENATION OF ETHYLENICALLY UNSATURATED AROMATIC POLYMERIC COMPOSITIONS, WHICH PROCESS COMPRISED INTRODUCING SAID POLYMERIC COMPOSITIONS DISPERSED IN A SUITABLE SOLVENT THEREFOR CONCURRENTLY WITTH HYDROGEN INTO A CONTACT WITH A NOBLE METAL CONTAINING CATALYST AT A TEMPERATURE OF 100 TO 350* C. AND AT AN LHSV OF 0.1 TO 10.

Use of polymeric complex for recovering metals

Abstract: A PROCESS FOR RECOVERING NOBLE METALS FROM A SOLUTION CONTAINING NOBLE METAL IONS BY TREATING SAID SOLUTION WITH A COMPLEX OF A CROSS-LINKED POLYMERIC N-VINYLAMIDE AND A POLYHYDROXYARYL COMPOUND.

Process for the production of halogen-substituted aromatic amines

Abstract: Halogen substituted aromatic amines are prepared by reducing the corresponding nitro compounds at a temperature of from 80* 130* C, under hydrogen pressure of from 10 - 150 atmospheres and at a pH of from 7 - 12 in an amount of watermisicible solvent sufficient to maintain a homogeneous phase during the reaction in the presence of from 1 to 25 percent by weight of a noble metal catalyst supported on active carbon, which catalyst has been used at least once in a catalytic hydrogenation reaction.

Redox Potential Measurements in Microbiological Media and Some Applications

Abstract: An apparatus has been designed and used to investigate the behavior of different type of “inert electrodes” of noble metals (platinum, gold) in model and microbiological media, in weak buffer solutions. These noble metal electrodes cannot be recommended for the determination of oxidation potentials in these systems. Glass electrodes are recommended for such experiments. The suitability of these electrodes for work in weak buffer systems has been evaluated and the influence of oxygen and of hydrogen ions determined. It has been established that within physiological limits the electrode redox-function does not depend on changes in the oxygen content of the medium or on the hydrogen ion activity. The potential of a redox-electrode in a weak buffer culture is considered (from an instrumental point of view) as a stationary potential. The absolute value of the stationary potential has been determined by Potentiometric titration, and examples of this determination are given. The interdependence of the potential with other parameters such as pH, content of dissolved oxygen, amount of micro-organism, and limiting concentration of substrate etc. is illustrated,

Process for adding cadmium to supported noble metal dehydrogenation catalyst

Abstract: Cadmium or zinc is added to a supported noble metal dehydrogenation catalyst by contacting the catalyst with an inert gas containing metallic cadmium or zinc vapors.

Aromatic hydrogenation process

Abstract: A process for hydrogenating hydrocarbons and mixtures of hydrocarbons utilizing a catalytic composite of a porous carrier material, a rhenium component, a germanium component and a Group VIII noble metal component. A specific example of one such process involves the hydrogenation of benzene to produce cyclohexane.

Electrolysis of dilute brine

Abstract: DILUTE BRINES ARE ELECTROLYZED TO PRODUCE CHLORINE, SODIUM HYDROXIDE AND HYDROGEN IN A DIAPHRAGM TYPE CHLOR-ALKALI CELL EQUIPPED WITH ANODES HAVING AN ACTIVE SURFACE ON AN ELECTRICALLY CONDUCTIVE SUBSTRATE METAL. APPLICABLE SUBSTRATE METALS ARE THOSE METALS AND METAL ALLOYS WHICH ARE PASSIVATED WHEN POLARIZED ANODICALLY AND REMAIN PASSIVE WELL BEYOND THE ANODIC POTENTIAL NEEDED TO CONVERT A CHLORIDE ION TO CHLORINE. THE ACTIVE SURFACE ON THE SUBSTRATE METAL IS A NOBLE METAL, ALLOYS THEREOF OR NOBLE METAL OXIDES ALONE OR IN COMBINATION WITH A NOBLE METAL. THE PRESENCE OF RELATIVELY HIGH CONCENTRATIONS OF IMPURITIES SUCH AS SODIUM SULFATE IN THE DILUTE BRINE CAN BE TOLERATED WITHOUT THE CHARACTERISTIC ANODE CURRENT EFFICIENCY LOSS WHICH ATTENDS THE USE OF GRAPHITE ANODES UP TO ABOUT 50 PERCENT OF THE DILUTE FEED BRINE CAN BE CONVERTED TO CAUSTIC CELL LIQUOR AND STILL OBTAIN ACCEPTABLE PERFORMACE OF THE CELL. THE ELECTROLYTIC DIAPHRAGM CELL EQUIPPED WITH ANODES HAVING AN ACTIVE SURFACE ON AN ELECTRICALLY CONDUCTIVE SUBSTRATE METAL WILL OPERATE WITH HIGH ANODE CURRENT EFFICIENCIES (ABOVE ABOUT 93%) ON VERY DILUTE CELL FEED BRINE IN COMPARISON TO CELLS EQUIPPED WITH GRAPHITE ANODES.

Method of melting laser glass in a noble metal container in a controlled reducing atmosphere

Abstract: This invention provides methods for melting glass laser compositions to provide glass laser rods with a minimum of noble metal inclusions and a minimum of dissolved noble metal content. The process comprises melting the laser glass in a noble metal container that is preferably platinum in a controlled reducing atmosphere in which the partial pressure of oxygen is between about 10 2 and 10 50 atmospheres.

Process for making catalytic noble metal complexes

Abstract: AS IMPROVEMENT IS DISCLOSED IN THE REACTION OF A HETEROAROMATIC NITROGEN COMPOUND WITH A ALKALI MEAAL-HALOGENOUS NOBLE METAL DERIVATIVE TO FORM A COMPLED. THE IMPROVEMENT RESIDES IN CONTROLLING THE PH OF THE REACTION MIXTURE WITHIN THE RANGE OF ABOUT 2.0-5.0 IN ORDER TO MINIMIZE NOBLE METAL LOSSES AND MAXIMIZE COMPLEX YIELD. THE PRODUCT COMPLEX IS OF UTILITY IN CATALYZING THE REACTION OF CATBON MONOXIDE WITH AROMATIC NITRO COMPOUNDS TO FORM AAOMATIC ISOCYANATES.

Continuous process for the purification of monochloroacetic acid

Abstract: DI- AND TRICHLOROACETIC ACID CONTAINED AS IMPURITTIES IN CRUDE MONOCHLOROACETIC ACID ARE PARRTIALLY DEHALOGENATEDD AND TRANSFORMED IN MONOCHLOROACETIC ACID AT A TEMPERATURE OF FROM 110 TO 145*C. IN A CONTINUOUS PROCESS IN THE PPRESENCE OF HYDROGEN WHILE TRICKLING THROUGH A CATALYST LAYER THE ACTIVE CONSTITUENT OF WHICH IS A NOBLE METAL OF SUBGROUP VIII OF THE PERIODIC TABLE.