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Showing papers on "Noble metal published in 1976"



Journal ArticleDOI
TL;DR: In the presence of noble metal salts, indoline reduced aromatic nitro-compounds to the corresponding aromatic amines under mild reaction conditions as mentioned in this paper, and indoline was shown to reduce amine compounds to indoline under mild conditions.
Abstract: In the presence of noble metal salts, indoline reduced aromatic nitro-compounds to the corresponding aromatic amines under mild reaction conditions.

37 citations


Patent
01 Jun 1976
TL;DR: A support material for platinum, platinum alloys, or other noble metal catalyst is made from carbon particles by heat treating the carbon until it is at least partially graphitized, depositing a metal on the heat treated carbon particles which will catalyze the oxidation of graphite in an oxidizing atmopshere, and oxidizing the surfaces of the heat-treated carbon particles at the sites of the catalyst crysals to pit or etch the surfaces at these sites.
Abstract: A support material for platinum, platinum alloys, or other noble metal catalyst, is made from carbon particles by heat treating the carbon until it is at least partially graphitized, depositing a metal on the heat treated carbon particles which will catalyze the oxidation of graphite in an oxidizing atmopshere, and oxidizing the surfaces of the heat treated carbon particles at the sites of the catalyst crysals to pit or etch the surfaces at these sites. When this material is used as a support for platinum it reduces the rate of platinum migration when the supported platinum catalyst is heated in the presence of a liquid, thereby reducing the loss of platinum surface area which often occurs under these conditions.

34 citations


Patent
09 Mar 1976
TL;DR: In this paper, a process for preparing active noble-metal catalysts on a carbon carrier is described, which involves adsorbing a salt of the catalytically active metal onto the carbon in an aqueous medium, and then hydrolyzing said salt to the oxide or hydroxide, by employing a basic reagent.
Abstract: The invention relates to a process for preparing active noble-metal catalysts on a carbon carrier. In particular, the process comprises adsorbing a salt of the catalytically active metal onto the carbon in an aqueous medium; hydrolyzing said salt to the oxide or hydroxide, by employing a basic reagent; and reducing said oxide or hydroxide to the metal.

32 citations


Journal ArticleDOI
K. Grob1
TL;DR: In this paper, the inner surface of tubings of Pt and other noble metals may, under certain conditions, become strongly active, such that the activity may increase to such an extent that severe band broadening, tailing, and even total disappearing of organic substances of various classes (not just polar ones) are caused.
Abstract: According to the experimental evidence reported in this paper, the inner surface of tubings of Pt and other noble metals may, under certain conditions, become strongly active. The activity may increase to such an extent that severe band broadening, tailing, and even total disappearing of organic substances of various classes (not just polar ones) are caused. Typically, noble metals constantly adapt their surface to the actual ambient conditions. It is not possible to maintain their surface in a given, preselected state. The most significant variable parameter influencing the surface is the nature of the effluent from a GC column. Upon column interchange, drastic changes in the surface characteristics of noble metal tubings can be observed. In contrast, a glass surface can be permanently inactivated and is not affected by varying effluents when columns are interchanged.

30 citations


Patent
06 Dec 1976
TL;DR: In this article, a method of bonding two crystals together is disclosed, where a bond enhancing material such as chromium (Cr) is vaporized on one crystal, and on this is vaporised a noble metal such as gold (Au).
Abstract: A method of bonding two crystals together is disclosed. A bond enhancing material such as chromium (Cr) is vapor deposited on one crystal, and on this is vapor deposited a noble metal such as gold (Au). On the other crystal a low melting point metal such as tin (Sn) or indium (In) is vapor deposited. In the case of In this can either be directly on the crystal or on a layer of bond enhancing material; in the case of Sn this must be on a bond enhancing material. On top of the low melting point metal a layer of the same noble metal is deposited to prevent oxidation thereof. The noble metal layers are brought into contact with each other in vacuum or inert atmosphere and pressure applied thereto at a temperature of 100° C to 150° C in the case of In and 100° C to 200° C in the case of Sn. The low melting point metal will diffuse into the noble metals and across the interface causing a bond to form by elimination of the boundary between the crystals.

30 citations


Patent
22 Nov 1976
TL;DR: In this article, the authors describe a catalyst capable of inducing reduction in nitrogen oxide pollutants of exhaust gases from internal combustion engines and industrial plants, which is formed from a mixture of catalytically active aluminum oxides and a mixture with at least two metal oxides, one which is chromium oxide and the other is an oxide of an element of the First Transition Series.
Abstract: A catalyst is described capable of inducing reduction in nitrogen oxide pollutants of exhaust gases from internal combustion engines and industrial plants. The catalyst composition is formed from a mixture of catalytically active aluminum oxides and a mixture of at least two metal oxides, one which is chromium oxide and the other is an oxide of an element of the First Transition Series, impregnated with about 1% by weight of an impregnant comprising a catalytically active noble metal compound. An optional constituent of the catalyst compositions includes 0.5-10% by weight of beryllium, magnesium, calcium, strontium or barium in the mixed oxide composition.

29 citations



Patent
Ludec Joel Le1
08 Mar 1976
TL;DR: In this paper, a process for the production of hydroxybenzaldehydes, especially salicylaldehyde, from the oxidation of the corresponding hydroxylbenzyl alcohol, with oxygen in an aqueous alkaline medium, in the presence of a noble metal catalyst, such as platinum or palladium, and a co-catalyst containing bismuth.
Abstract: A process is provided for the production of hydroxybenzaldehydes, especially salicylaldehyde, from the oxidation of the corresponding hydroxybenzyl alcohol, especially orthohydroxybenzyl alcohol, with oxygen in an aqueous alkaline medium in the presence of a noble metal catalyst, such as platinum or palladium, and in the presence of a co-catalyst containing bismuth.

25 citations


Patent
30 Jan 1976
TL;DR: A photographic silver halide emulsion capable of forming on exposure an internal latent image can be formed having a desired characteristic curve by providing a first photographic luminous emulsion comprised of silver halides internally sensitized with a combination of middle chalcogen and noble metal sensitizers as mentioned in this paper.
Abstract: A photographic silver halide emulsion capable of forming on exposure an internal latent image can be formed having a desired characteristic curve by providing a first photographic silver halide emulsion comprised of silver halide grains internally sensitized with a combination of middle chalcogen and noble metal sensitizers capable of forming on exposure an internal latent image and blending therewith a second, higher contrast photographic silver halide emulsion comprised of silver halide grains internally sensitized with a relatively lower proportion of middle chalcogen to noble metal sensitization. Both the first and second photographic silver halide emulsions are sensitized with the same middle chalcogen and noble metal sensitizers.

23 citations


Journal ArticleDOI
TL;DR: In the presence of noble metal salts, especially Pd(II) salts, the carbon-halogen bond of aryl halides underwent hydrogenolysis with organic hydrogen donors such as indoline and tetrahydroquinoline.
Abstract: In the presence of noble metal salts, especially Pd(II) salts, the carbon–halogen bond of aryl halides underwent hydrogenolysis with organic hydrogen donors such as indoline and tetrahydroquinoline, and the corresponding aryl compounds and hydrogen halides were formed. The addition of bases promoted the hydrogenolysis.

Journal ArticleDOI
TL;DR: In this article, the effects of TEL and halide compounds, such as ethylene dibromide and ethylene dichloride, on Pt and Pd oxidation catalysts were investigated in the laboratory.
Abstract: The separate and combined effects of TEL and the halide compounds, ethylene dibromide and ethylene dichloride, on Pt and Pd oxidation catalysts were investigated in the laboratory. Automobile exhaust was simulated by controlled combustion of isooctane. Of the two scavengers, only ethylene dibromide decreases catalyst activity. Deactivation is especially severe for catalysts containing Pd. Pure isooctane restores activity completely. Scavengers alone do not enhance shrinkage of the noble metal surface. TEL causes permanent deactivation and irreversible loss of the Pt-Pd surface area. Total lead deposit, residual noble metal surface, and catalyst activity are not a simple function of the lead deposit, but depend on the combination of the additives. (auth)


Patent
15 Sep 1976
TL;DR: An improved gas permeable hydrophobic electrode and its method of manufacture is provided in this paper, which includes a current collecting grid formed of an electrically conductive metal, e.g. platinum, gold, stainless steel, nickel-clad iron, nickel wire mesh, expanded nickel, or expanded silver.
Abstract: An improved gas permeable hydrophobic electrode and its method of manufacture is provided. The electrode includes (a) a current collecting grid formed of an electrically conductive metal, e.g. platinum, gold, stainless steel, nickel-clad iron, nickel wire mesh, silver wire mesh, expanded nickel, or expanded silver; (b) a noble metal catalyst, e.g. silver, platinum or palladium catalyst deposited on, and adhered to, both side faces of the current collecting grid, e.g. the nickel grid, such noble metal catalyst, e.g. silver, having been deposited in situ on a fugitive substrate, e.g. aluminum foil, from a paste of an aqueous suspension of a water-soluble metal salt, e.g. silver salt, a fluorocarbon polymer, e.g. polytetrafluoroethylene, a wetting agent, e.g. octyl phenoxpolyethoxyethanol and activated carbon, which is subsequently dried and cured at a temperature not exceeding about 150° C.; and (c) a hydrophobic semi-permeable membrane, e.g. a fibrous polytetrafluoroethylene membrane or a microporous polypropylene membrane on one side of such coated grid. The improved method of manufacture involves applying the above-noted paste to a fugitive substrate and then drying and curing such paste at a temperature not exceeding about 150° C.

Patent
05 Nov 1976
TL;DR: In this article, the authors proposed a noble metal hydrogenation component for the conversion of a Bronsted acid containing fluorine to a hydrocarbon feedstock, in the presence of molecular hydrogen and under suitable regeneration conditions.
Abstract: Hydrocarbon conversion catalysts comprising a metal halide in combination with a Bronsted acid containing fluorine that have become deactivated or partially deactivated by the formation of allyl and alkylaromatic carbonium ion complexes with the acid during contact with a hydrocarbon feedstock may be regenerated by contacting said catalyst, in the presence of molecular hydrogen and under suitable regeneration conditions, with a noble metal hydrogenation component. A preferred catalyst comprises tantalum pentafluoride and hydrogen fluoride. Palladium is the preferred noble metal hydrogenation component.

Journal ArticleDOI
TL;DR: In this article, the kinetics of oxygen sorption by vapour-deposited films of twelve metals, Ag, Cu, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ni and Fe, have been determined between 77 and 400 K by an identical volumetric technique.

Patent
01 Nov 1976
TL;DR: An improvement in a process for the preparation of chlorinated aromatic amines by hydrogenation of the corresponding chlorinated nitro-aromatic compounds in the presence of a noble metal catalyst on a carbon support was described in this article.
Abstract: An improvement in a process for the preparation of chlorinated aromatic amines by hydrogenation of the corresponding chlorinated nitro-aromatic compounds in the presence of a noble metal catalyst on a carbon support and in the presence of a sulfur compound, the improvement residing in that the sulfur compound is a thio-ether. Preferably the reaction is carried out in a weakly basic medium.

Journal ArticleDOI
TL;DR: In this article, the authors combined results of electromodulated reflectometric and ellipsometric measurements may provide better diagnostic criteria in the analysis of the growth of very thin films on metal electrodes.

Patent
17 Dec 1976
TL;DR: A support material for platinum, platinum alloys, or other noble metal catalyst is made from carbon particles by heat treating the carbon until it is at least partially graphitized, depositing a metal on the heat treated carbon particles which will catalyze the oxidation of graphite in an oxidizing atmosphere, and oxidizing the surfaces of the heat-treated carbon particles at the sites of the catalyst crystals to pit or etch the surfaces at these sites as mentioned in this paper.
Abstract: A support material for platinum, platinum alloys, or other noble metal catalyst, is made from carbon particles by heat treating the carbon until it is at least partially graphitized, depositing a metal on the heat treated carbon particles which will catalyze the oxidation of graphite in an oxidizing atmosphere, and oxidizing the surfaces of the heat treated carbon particles at the sites of the catalyst crystals to pit or etch the surfaces at these sites. When this material is used as a support for platinum it reduces the rate of platinum migration when the supported platinum catalyst is heated in the presence of a liquid, thereby reducing the loss of platinum surface area which often occurs under these conditions.

Patent
06 Dec 1976
TL;DR: In this article, a process for improved three-way emissions control comprising the steps of contacting the emissions stream with a first catalyst consisting of rhodium supported on a refractory substrate to effect the selective chemical reduction of nitric oxide to nitrogen, was described.
Abstract: A process for improved three-way emissions control comprising the steps of contacting the emissions stream with a first catalyst consisting of rhodium supported on a refractory substrate to effect the selective chemical reduction of nitric oxide to nitrogen, said rhodium being present in an amount of at least about 0.002% by weight of the catalyst, said emissions stream being then contacted with a second catalyst consisting of at least one of the noble metals selected from the group of platinum and palladium, said noble metal being present in a small but effective amount to accomplish the oxidation of the hydrocarbons and carbon monoxide left in said emissions stream, said process being accomplished without the addition of oxygen to said emissions stream.

Book ChapterDOI
TL;DR: After closing of the electric circuit in the beginning of a PO2-measurement with a bare noble metal electrode, the primary current is high but decreases rapidly in form of a first steep, then gradually flattening curve and approaches a decisively lower value finally.
Abstract: After closing of the electric circuit in the beginning of a PO2-measurement with a bare noble metal electrode, the primary current is high but decreases rapidly in form of a first steep, then gradually flattening curve and approaches a decisively lower value finally (fig. 1).

Journal ArticleDOI
H. Kohlmüller1
TL;DR: In this article, it was shown that the intermetallic compound Pt3Pb exhibited an activity approximately ten times higher than pure platinum in the anodic oxidation of ethylene glycol to oxalic acid.

Patent
14 Jul 1976
TL;DR: In this paper, a stabilised ion-conducting solid electrolyte (A) with electrode layers sintered on both sides, >= 1 of which is a single layer 10-500 um thick are made from a mixt. Amt. of noble metal powder (B) and powder form.
Abstract: Probes consisting of a stabilised ion-conducting solid electrolyte (A) with electrode layers sintered on both sides, >=1 of which is a single layer 10-500 um thick are made from a mixt. of noble metal powder (B), and (A) in powder form. Amt. of (A) in the mixt. is 5-75 wt.%. The probes can be used for measuring oxygen concn. of exhaust gases of vehicles. The electrode layer has good adhesion, with no loosening or peeling from the solid electrolyte body in service. It has excellent catalytic properties with long life, and can be made with high productivity and low cost.

Patent
16 Jul 1976
TL;DR: In this article, a common metal contact material which forms, in an oxygen-containing atmosphere or in air, non-porous insulating oxides, is coated with a porous noble metal or noble metal alloy cover layer, the pores or regions not covered by the noble metals or nobel metal alloy being permitted to oxidize to form a protective common metal oxide, the noble metal regions in contact with the underlying contact material providing for the electrical connection.
Abstract: To reduce costs and permit use of a smaller amount of noble metals in nobel metal contacts, a common metal contact material which forms, in an oxygen-containing atmosphere or in air, non-porous insulating oxides, is coated with a porous noble metal or noble metal alloy cover layer, the pores or regions not covered by the noble metal or nobel metal alloy being permitted to oxidize to form a protective common metal contact material oxide, the noble metal regions in contact with the underlying contact material itself providing for the electrical connection. Preferably, the porous cover layer has a thickness of between about 0.1 to 0.2 μm, and the contact material, separately or applied to a carrier, has a thickness of between 2 to 100 μm, preferably about 10 μm, and comprises aluminum, titanium, niobium, chromium, silicon, zirconium or tantalum, the noble metal preferably being gold or a gold alloy, applied under exclusion of oxygen to the underlying contact material after any oxide skin thereon has been removed.

Journal ArticleDOI
TL;DR: In this paper, the η 1 component of hydrogen overpotential at palladium-black-coated electrodes of palladium, palladium/platinum alloys, niobium and tantalum in hydrogen-saturated acidic solutions was investigated.

Patent
05 Apr 1976
TL;DR: An electrode, for use in electrolytic processes, comprises a valve metal substrate, such as titanium, a coating thereon of conductive tin oxide, and an outer coating of a noble metal or noble metal oxide as discussed by the authors.
Abstract: An electrode, for use in electrolytic processes, comprises a valve metal substrate, such as titanium, a coating thereon of conductive tin oxide, and an outer coating of a noble metal or noble metal oxide.

01 Jan 1976
TL;DR: In this paper, a copper chromite ZrO/sub 2/ honeycomb honeycomb catalyst has been evaluated in the laboratory and to a limited extent on vehicles and the results showed that the performance of this catalyst was comparable to that of a high catalyst loading base metal catalyst.
Abstract: A copper chromite ZrO/sub 2/ honeycomb catalyst has been evaluated in the laboratory and to a limited extent on vehicles. When 650 to 850 grams of this catalyst (1.4 to 1.9 lbs) is dispersed on two honeycombs and used to catalytically treat the exhaust of a 4500 lb, 400 in/sup 3/ Torino, the percent oxidation of CO and hydrocarbons during the Federal Test Procedure are close to, but less than that produced by present noble metal production catalysts. The total active catalyst surface area available with copper chromite ZrO/sub 2/ catalyst is somewhat marginal and this leads to pronounced susceptibility to lead deactivation during durability even at very low lead levels if the peak catalyst operating temperature is high (900/sup 0/C). It is desirable to operate below 700 to 750/sup 0/C. Catalyst operating temperatures greater than 550 to 600/sup 0/C are necessary to suppress sulfur deactivation without special operating procedures so that this leaves only a narrow temperature range of operation if the catalyst activity is to be preserved. Catalysts containing a low level of palladium appear to offer a competitive alternate to the use of a high catalyst loading base metal catalyst. The problem of a limited total activemore » catalyst surface area and susceptibility to lead are still present but other constraints are eased.« less

Patent
29 Mar 1976
TL;DR: In this article, a method for preparing gamma-chloromethyl-gamma-butyrolactone is described, which consists of contacting 4-pentenoic acid with air or oxygen and a catalyst comprising a noble metal halide, a variable valence transition metal, and an alkali metal, at a temperature between 50° and 200° C and superatmospheric pressure.
Abstract: A method for preparing a gamma-chloromethyl-gamma-butyrolactone which comprises contacting 4-pentenoic acid with air or oxygen and a catalyst comprising a noble metal halide, a variable valence transition metal halide and an alkali metal halide at a temperature between 50° and 200° C and superatmospheric pressure.

Patent
07 Aug 1976
TL;DR: In this paper, the authors proposed a method to recover efficiently high pusity noble metals by combining the process, which contains adsorption of the noble metal s to ion exchange resin from the specified extraction liquid containing the noble metals extracted from waste catalyzer and the reduction recovery, with the recovering process of the ion substitution etc.
Abstract: PURPOSE: To recover efficiently high pusity noble metals by combining the process, which contains adsorption of the noble metal s to ion exchange resin from the specified extraction liquid containing the noble metals extracted from waste catalyzer and the reduction recovery, with the recovering process of the ion substitution etc. in the waste liquid. COPYRIGHT: (C)1978,JPO&Japio