Showing papers on "Noble metal published in 1972"

Preparation of a silver salt of a fatty acid

Abstract: A process for preparing a silver salt of a fatty acid in finely divided form comprising (a) adding an aqueous solution of a water-soluble noble metal salt to a colloidal dispersion comprising the ammonium or alkali metal salt of the fatty acid, (b) optionally adding an acidic solution to the resulting reaction mixture to convert unreacted ammonium or alkali metal salt to the free fatty acid, and (c) recovering the noble metal salt of the fatty acid, provides noble metal salts of fatty acids which can be used in photographic materials.

Noble metal catalysts

Abstract: THE PRESENT INVENTION IS CONCERNED WITH CATALYSTS IN WHICH THE ACTIVE COMPONENTS ARE HIGHLY DISPERSED AND STABLE NOBLE METALS. IN ONE SPECIFIC ASPECT, THE INVENTION DEALS WITH CATALYST USEFUL IN THE REDUCTION OR ELIMINATION OF NOXIOUS COMPONENTS IN AUTO EXHAUST GASES. IN ANOTHER SPECIFIC ASPECT, THE INVENTION DEALS WITH THE STABILIZATION OF NOBLE METALS BY SELECTED SUPPORTS.

Process for separation of unsaturated hydrocarbons

Abstract: There is described the separation of aliphatically unsaturated hydrocarbons from mixtures by the combined use of liquid barrier permeation and metal complexing techniques. The liquid barrier is in contact with a film membrane, and the barrier contains complex-forming metal ions in aqueous solution. The metal ions may be, for example, noble metal, mercuric, cuprous or other metal ions, and mixtures of these metal ions, with or without other cations, may be used. The separation of ethylene from ethane and methane is of particular interest.

Process for the production of vinyl esters

Abstract: IMPROVEMENT IN A PROCESS FOR THE PRODUCTION OF VINYL ESTERS BY REACTING ETHYLENE, LOWER CARBOXYLIC ACIDS WITH 2 TO 4 CARBON ATOMS AND OXYGEN IN THE GAS PHASE AT ELEVATED TEMPERATURE AND NORMAL OR ELEVATED PRESSURE, IN THE PRESENCE OF SUPPORTED CATALYST CONSISTING ESSENTIALLY OF PALLADIUM, GOLD AND AN ALKALI METAL ACETATE ON A SILICIC ACID SUPPORT, WHICH IMPROVEMENT COMPRISES PREPARING THE CATALYST BY TREATING THE SUPPORT, SIMULTANEOUSLY OR SUCCESSIVELY OR IN COMBINATION WITH A SOLUTION A DND A SOLUTION B, THE SOLUTION A CONTAINING DISSOLVED SALTS OF PALLADIUM AND GOLD AND THE SOLUTION B CONTAINING COMPOUNDS WHICH ARE ABLE TO REACT ON THE CATALYST SUPPORT WITH THE NOBLE METAL SALTS OF THE SOLUTION A TO FORM WATER-IN-SOLUBLE NOBLE METAL COMPOUNDS WHICH ARE SUBSTANTIALLY FREE OF HALOGEN, SULPHUR AND NITROGEN, IMPREGNATING THE CATALYST SUPPORT WITH THE SOLUTIONS A AND B IR WITH THE COMBINED SOLUTION OF A AND B IN QUANITIES WHICH CORRESPOND TO FROM 1 TO 110% OF THE ABSORPTIVE CAPACITY OF THE CATALYST SUPPORT FOR THESE SOLUTIONS: SUBJECTING THE CATALYST SUPPORT IMPREGNATED WITH THE SOLUTIONS A AND B TO A TIME/ TEMPERATURE-TREATMENT WHICH IS SUCH THAT 95% AT LEAST OF THE IMTHE IMPREGNATED PALLADIUM AND 95% AT LEAST OF THE IMPREGNATED GOLD IS TRANSFORMED INTO WATER-INSOLUBLE NOBLE METAL COMPOUNDS, TREATING THE WATER-INSOLUBLE NOBLE COMPOUNDS WITH A REDUCING AGENT TO COVEY THESE COMPOUNDS SUBSTANTIALLY INTO THE CORRESPONDING NOBLE METALS AND REMOVING THE WATER-SOLUBLE COMPOUNDS WHICH ARE CONTAINED IN THE CATALYST BY WASHING, AND APPLYING AN ALKALI METAL COMPOUND BEFORE OR AFTER THE TREATMENT WITH THE REDUCIING AGENTS, THE ALKALI METAL COMPOUNDS CONSISTING OF ALKALI METAL CARBOXYLATES OR OF ALKALI METAL COMPOUNDS WHICH ARE WHOLLY OR IN PART TRANSFORMED INTO ALKALI METAL CARBOXYLATES UNDER THE REACTION CONDITIONS.

Process for treating automotive exhaust

Abstract: FOR USE IN THE TREATMENT OF AUTOMIBILE EXHAUST GASES, A CATALYST COMBINATION HAVING BOTH OXIDATION AND REDUCTION CAPABILITY IS EMPLOYED IN A FIRST CONVERTER, THE CATALYST HAVING A RUTHENIUM CONTAINING SECTION FOLLOWED BY A SECTION CONTAINING ANOTHER NOBLE METAL, E.G., RHODIUM. NITROGEN OXIDES ARE REMOVED WITH LITTLE PRODUCTION OF AMMONIA.

Oxalic acid (ester) prepn - from carbon monoxide and oxygen

Abstract: Oxalic acid (esters) are prepd by oxidn of CO in aq or alcoholic phase with O2 under press at elevated temp and using a catalyst system formed from a salt or a complex cpd of a Pt metal and a salt or a complex of a further metal which is more electropositive than the noble metal and which can occur in several oxidn states

Nickel-free, all metal, catalyst element

Abstract: An all metal, high temperature resistant, catalyst element is provided by plating or depositing a noble metal comprising platinum and/or palladium onto a base material which comprises primarily aluminum, chromium and iron. The nickel-free, aluminum containing base material appears to be of advantage for at least certain all metal catalyst element operations and also results in substantially lower first cost catalyst units.

Catalyst systems for the reduction of the oxides of nitrogen

Abstract: Devices and processes are disclosed for the treatment of waste gases, particularly automotive exhaust gases, to remove the oxides of nitrogen therefrom Mixed noble metal catalysts consisting essentially of platinum or palladium and at least one other noble metal selected from the group consisting of ruthenium, rhodium, and iridium are employed in combination with layered oxide support coatings to eliminate ammonia formation during the removal process

Process for producing a catalyst

Abstract: A film of a noble metal is deposited on the surface of a carrier without substantial penetration of the carrier by immersing the carrier first in a dilute solution of a salt of the noble metal, removing the carrier and heating and drying it to produce precipitation cores of the noble metal on the surface of the carrier, and then immersing the carrier with the precipitation cores in a solution of a noble metal salt which also contains a reducing agent for the salt and a stabilizer for the solution. The film of noble metal thus produced on the surface is adherent thereto and is highly active as a catalyzer for removing pollutants from the exhaust gas of an automobile.

Production of benzene

Abstract: ALKYL AROMATIC HYDROCARBONS, FOR EXAMPLE, TOLUENE ARE DEALKYLATED TO YIELD BENZENE AND HYDROGEN IN THE PRESENCE OF STEAM AND, OPTIONALLY, HYDROGEN OVER A GROUP VIII NOBLE METAL CATALYST SUPPORTED ON ALPHA-ALUMINA. THE HYDROGEN GENERATED IS USED TO SUPPLY AT LEAST PART OF THE HYDROGEN REQUIREMENT FOR A HYDRODEALKYLATION PROCCESS, OPTIONALLY CARRIED OUT STIMULTANEOUSLY WITH THE STEAM DEALKYLATION PROCESS IN A COMMON REACTOR.

Noble metals solvation agents-hydroxyketones and iodine and iodide

Abstract: PROCESSES FOR AND COMPOSITIONS UTILIZED IN THE RECOVERY OF NOBLE METALS FROM NOBLE METAL CONTAINING SUBSTANCES BY SUBJECTING SUCH SUBSTANCES-PREFERABLY IN COMMINUTED FORM-TO THE ACTION OF A SOLVENT PREFERABLY COMPRISING DIACETONE ALCOHOL AS A MAJOR COMPONENT, WATER, MINOR AMOUNTS OF GLACIAL ACETIC ACID, POTASSIUM IODIDE AND ELEMETAL IODINE. SOLVATION OF THE NOBLE METAL OCCURS DURING AGITATION AND HEATING OF THE SLURRY. THE NOBLE METAL CONTANTS ARE REMOVED FROM THE NOBLE METAL PREGNANT SOLUTION BY DISPLACEMENT ONTO A NON-NOBLE METAL SURFACE. THE SOLID NOBLE METAL CONTAINING RESIDUE IS TREATED WITH SUFFICIENT AQUEOUS HYDROXIDE SOLUTION TO CONVERT EXCESS NON-NOBLE METAL INTO ITS WATER-SOLUBLE SALT. THE REMAINING INSOLUBLE MATERIAL CONTAINING THE NOBLE METAL RECOVERED IS RINSED TO REMOVE ANY REMAINING UNREACTED ALKALI AND THE SOLUBLE SALTS AND IS THEN DIGESTED WITH CONCENTRATED SULFURIC ACID TO DISSOLVE ANY REMAINING ACID SOLUBLE IMPURITIES, THE REMAINING ACID INSOLUBLE RESIDUE IS RINSED, DRIED AND COMPRISES SUBSTANTIALLY PURE NOBLE METAL.

Method of preparing a catalyst of a group viii noble metal and tin

Abstract: CATALYSTS CONTAINING GROUP VIII NOBLE METALS AND TIN ON A CARRIER ARE PREPARED BY DEPOSITING TIN ON THE CARRIER WITH AN AQUEOUS INORGANIC SALT SOLUTION HAVING TIN PRESENT IN THE ANION.

Process for depositing noble metal catalysts on oxide carriers

Abstract: 1. IN A PROCESS FOR DEPOSITING A NOBLE METAL CATALYST ON A REFRACTORY METAL OXIDE CARRIER WHICH COMPRISES THE STEP OF CONTACTING THE REFRACTORY METAL OXIDE CARRIER WITH A SOLUTION CONTAINING A FORMIC ACID REDUCTANT AND NOBLE METAL IONS SELECTED FROM THE GROUP CONSISTING OF PALTINUM, PALLADIUM, RHODIUM, GOLD, SILVER AND MIXTURES THEREOF, THE IMPROVEMENT WHICH COMPRISES THE ADDITION OF UREA TO THE SOLUTION IN AN AMOUNT RANGING ABOUT 1-110% BY WEIGHT THEREOF.

Relaxation time effects in the stacking fault energy of noble metal alloys

Abstract: The stacking fault energy, γ, in noble metal alloys can be expressed as a sum of two terms: δufe, the contribution due to the conduction electrons; and δuc, the contribution due to thed electrons. For noble metals and alloys δuc 〉 δufe while for multivalent normal metals δufe 〉 δuc. The theory is first discussed in terms of recent calculations of the pseudopotential form factors of the noble metals (Moriarty) and some of the typical solutes (Shaw). The theory is then extended in a phenomenological fashion to include the effects of a finite relaxation time, τ, of the conduction electrons. It is shown that, for concentrated noble metal alloys with the electron-to-atom ratio,Z 〉 1.14 and multivalent normal metals, δufe and hence γ will be dependent on both temperature and deformation through their effects on τ. An increase in τ results in a decrease in the magnitude of δufe. In the case of concentrated noble metal alloys this results in an increase in γ with increasing t while for multivalent normal metals γ decreases with increasing τ.

Process for separating gas by diffusion

Abstract: There is described the separation of aliphatically-unsaturated hydrocarbons of two to four carbon atoms from gaseous mixtures by the combined use of liquid barrier permeation and metal complexing techniques. The liquid barrier is in contact with a film membrane, and the barrier contains complex-forming metal ions in aqueous solution. The film membrane is contacted with a swelling agent to increase the selectivity of the separation and, preferably, increase permeation by the aliphatically unsaturated hydrocarbon to be separated. The metal ions in the liquid barrier may be, for example, noble metal, nickel, mercurous, cuprous or other metal ions, and mixtures of the metal ions, with or without other cations, may be used. The separation of ethylene from ethane and methane is of particular interest.

Galvanic corrosion resulting from rupture of a protective metallic coating

Abstract: A treatment of corrosion of galvanic couples in which the area of one metal greatly exceeds that of the other has been carried out using mixed potential theory. A ruptured metallic coating on a metal substrate is encompassed by the treatment, as is a metal containing inclusions of a second metal as impurity. Two cases are examined. In the first, exemplified by zinc-plated steel, three reactions are considered: dissolution of the coating and reduction of the oxidizing agent on each metal. In this case, the result of the rupture is often a very marked increase in the corrosion of the coating, leading to an autocatalytic effect. The second case treats an active metal protected by a coating of a more noble metal. The following reactions are considered: both directions of the redox couple generated by the oxidizing agent, and the dissolution of the substrate. It is demonstrated that in the second case the corrosion rate is maximal at vanishingly small porosities. In both cases, variations of the corrosion potential can be used as a measure of porosity.

Process for preparing ultra stable exhaust catalyst of improved activity

Abstract: 1. A PROCESS FOR PREPARING AN ULTRA-STABLE CATALYST FOR THE CONVERSION OF THE NOXIOUS COMPONENTS OF EXHAUST GASES TO INNOCUOUS ENTITIES CONSISTING ESSENTIALLY OF: (A) IMPREGNATING A SUPPORT SELECTED FROM THE GROUP CONSISTING OF ALUMINA, MULLITE, SILICA, CORDIERITE, AND SILICA-ALUMINA OF SUFFICIENT SURFACE AREA WITH A SOLUTION OF A SOLUBLE SALT OF CERIUM WHICH UPON CALCINATION PROVIDES CERIUM OXIDE ON THE SUPPORT, (B) CALCINING THE IMPREGNATED SUPPORT IN AIR BY HEATING TO A TEMPERATURE OF ABOUT 1000* TO 2000*F. TO CONVERT THE CERIUM TO OXIDE FORM, (C) CONTACTING THE IMPREGNATED SUPPORT WITH A SUFFICIENT QUANTITY OF A SOLUTION OF A SALT OF A NOBLE METAL SELECTED FROM THE GROUP CONSISTING OF PLATINUM, PALLADIUM AND MIXTURES THEREOF, AND A SOLUBLE CERIUM SALT TO IMPART A NOBLE METAL CONTENT OF 0.01 TO 5 PERCENT AND A FINAL CERIUM OXIDE CONTENT OF 2 TO 90 PERCENT WITH RESPECT TO THE SUPPORT, (D) CALCINING TO ABOUT 900* TO 1200*F. FOR ABOUT 2-6 HOURS, AND (E) RECOVERING THE CATALYST PRODUCT.

Ammoniacal etching solution and method utilizing same

Abstract: An aqueous ammoniacal etching solution for metallic surfaces contains, at makeup, ammonium haloacetate, ammonium hydroxide, and a promoter selected from the group consisting of soluble iodide, bromide and noble metal compounds; preferably, the solution also contains a soluble cupric compound. The solution may be used for spray or immersion etching of copper, cadmium, zinc, aluminum and alloys of such metals.

Thermotransport of Noble Metal Impurities in Lead

Abstract: Abstract Steady-state distributions of Au, Ag and Cu tracers in Pb wafers subjected to temperature gradients have been determined. The effective heats of transport were + 5.8 ± 1.1 for Ag, - 0.5 ± 0.3 for Au, and of the order of + 35 for Cu (all in kcal/mole, positive values denoting the impurity migrating to the cold side of the Pb wafer). No significant temperature dependence of the heats of transport could be detected. The results are difficult to reconcile with existing theories of the intrinsic and electronic contribution to the heat of transport.

Sorption agent for nonsolid metals

Abstract: 1. A METHOD OF COLLECTING A LIQUID METAL SELECTED FROM THE GOUP CONSISTING OF MERCYRY, GALLIUM, ROSE''S METAL, AND WOOD''S METAL WHICH COMPRISES CONTACTING SAID LIQUID METAL WITH A SOLID, ABSORBENT CARRIER IMPREGNATED WITH A WATER-SOLUBLE SALT OF A METAL MORE NOBLE THAN SAID LIQUID METAL UNTIL SAID LIQUID METAL REACTS WITH SAID SALT OF THE MORE NOBLE METAL TO FORM A SALT OF SAID LIQUID METAL, AND THE FORMED SALT IS ABSORBED BY SAID CARRIER.

Production of catechol

Abstract: Catechol is produced by the controlled dehydrogenation of dihydrocatechol Dihydrocatechol is added at a gradual rate to a slurry of a noble metal catalyst and a refluxing solvent The gradual addition of the dihydrocatechol to the slurry and the refluxing of the solvent serve to minimize the formation of undesirable by-products