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Platinum Metals Rev., 1968, 12, (3), 115

NEW PATENTS: July 1968

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METALS AND ALLOYS

Manufacture of Precious Metal Spheres and Spheroids

international nickel ltd. British Patent 1,103,396

Small spheres or spheroids of alloys of Ru, Rh, Os and Ir are used for points of moving elements, e.g. in compasses, and fountain pen nibs. They are produced by heating a powder of one of these four metals with a matrix mixture of Pd or Pt with Au or Ag above the melting point of the matrix but below that of the four metals, forming the product into spheres, cooling and leaching out the matrix.

Niobium Alloys

birmingham small arms co. ltd. British Patent 1,103,724

The strength of Nb-W alloys, with or without Ta, is improved by the addition of one or more of Ru, Os and Ir. The range claimed is at least 30% Nb, 10−25% W, 0−40% Ta and 0.1−10% Pt metal. Small amounts of Hf and Zr may also be present.

Preparation of Finely Divided Metals

international nickel ltd. British Patent 1,109,890

Finely divided Ir or Ru is produced by thermally decomposing a halogen-free Ir or Ru compound at up to 400°C in non-oxidising conditions, the Ir or Ru atom being in a complex with NH3 and/or oxalate groups, the other groups in the compound leaving no residue on decomposition. A typical compound is (NH4)3[Ru(CO)3(C2O4)].

Manufacturing Non-Magnetic, Elastic Metallic Materials

zaidan hojin denki jiki zairyo kenkyusho British Patent 1,110,045

These materials are produced from metallic Pd or an alloy of 30−100 wt% Pd and 70−0 wt% Au by heating the metal or alloy at above 600°C but below its melting point for more than one minute and then slowly cooling it to achieve annealing. It is permissible for 0−5% of a variety of other alloying elements to be present.

Reorientation of Stabilised Platinum

johnson, matthey & co. ltd. Italian Patent 787,630

French Patent 1,504,716

Mechanical properties of a strengthened metal or alloy are improved by cold-working and annealing. The cold-working causes recrystallisation during annealing with a grain structure elongated in the direction of working. Pt and Rh-Pt are strengthened prior to treatment by the inclusion of a dispersed carbide.

Platinum Claddings for Refractory Metals

johnson, matthey & co. ltd. Italian Patent 794,340

Articles comprise refractory metal cores, such as Nb, Ta, Cr, or an alloy thereof, or Mo, which do not form volatile oxides at the operating temperature nor form alloys with the Pt or Pt alloy cladding at melting points below this temperature. A barrier layer between core and cladding consists of a compatible refractory carbide, silicide, boride, sulphide, nitride, or oxide, e.g. a rare earth metal oxide, carbide or nitride. This corresponds to Belgian Patent 697,292.

CHEMICAL COMPOUNDS

Production of Platinum and Palladium Oxides

matthey bishop inc. U.S. Patent 3,357,904

These oxides are made by electrolysis using an electrode comprising or containing Pt and/or Pd in a bath of molten alkali metal hydroxide.

ELECTROCHEMISTRY

Electrodes for Cells

central electricity generating board British Patent 1,104,374

Electrodes for electrolytic cells particularly for the direct electrolysis of sea water to produce hypochlorite is based on a cheaper anode material which is covered with a Pt-Ni alloy containing not less than 30% Pt covered with a pure Pt film.

ELECTRODEPOSITION AND SURFACE COATINGS

Surface Treatment of Titanium

imperial metal industries (kynoch) ltd. British Patent 1,105,388

Before plating Pt on to Ti surfaces, they are pretreated with an oxalic acid solution at elevated temperature. The adherence of the Pt electro-deposit is improved.

Platinum Plating of Titanium

ste ugine U.S. Patent 3,357,858

A Pt group metal plated deposit adheres well to articles with a Ti or Ti alloy surface when the surface is pretreated with a mixture of HCl and HNO3 and the deposit is heated at 300°C.

Activation of Glass before Chemical Plating

international business machines corp. U.S. Patent 3,370,973

Glass is coated with an organic solution of nickel chloropalladate and then heated at elevated temperature to convert the coating to a Ni-Pd film. This film catalysed subsequent chemical (electroless) plating baths.

Coatings on Easily Oxidised Metals

international nickel ltd. French Patent 1,500,545

Bodies formed of Ir, Ru, Mo, W or their alloys with noble metals are protected against oxidation at high temperatures by coating with a ternary alloy containing Au and Pt or Pd.

Platinum Metal Plating

deutsche gold- & silber-scheideanstalt German Patent 1,261,367

Refractory metals are coated by applying a sulphur-free chelate of a Pt metal dissolved in an organic solvent, allowing the solvent to evaporate and then decomposing the metal chelate at a temperature up to 400°C. Aliphatic dinitriles and decarboxylic acids are suitable chelating agents.

JOINING

Brazing Methods for Porous Refractory Metals

t.r.w. inc. U.S. Patent 3,363,306

Porous W is bonded to other refractory metals, such as Mo or massive W, using a thin layer of Rh which wets the metal surfaces and forms an alloy on heating.

Refractory Ceramic to Metal Seal

north american philips co. U.S. Patent 3,366,466

Ceramics are metallised with a spongy layer of Mo and/or W, the pores of the spongy layer are filled with a Ta-Rh, Rh-Mo or Mo-Ru alloy which also covers the surface and then a braze containing a Ta or Nb alloy is applied. See also British Patent 1,108,764.

HETEROGENEOUS CATALYSIS

Production of Unsaturated Mononitriles

farbwerke hoechst a.g. British Patent 1,103,046

Acrylonitrile and related compounds are produced by reacting an olefin with HCN and O2 at an elevated temperature in the presence of a Pt metal catalyst, especially a supported Pd catalyst.

Production of Vinyl Acetate

knapsack a.g. British Patent 1,103,125

Vinyl acetate is produced from C2H4, CH3COOH and O2 in the gas phase using a carrier catalyst containing 0.1−6 wt% (preferably 0.5−2%) metallic Pd, 0.01−10 wt% (preferably 0.03−1%) metallic Au and 1−20 wt% (preferably up to 5 wt%) alkali metal formate or acetate. See also British Patent 1,107,495.

Hydrocracking Process

esso research & engineering co. British Patent 1,103,393

The activity of catalysts made by depositing a Pt metal on a base-exchanged zeolite with 6−15Å pore openings is maintained and increased by adding halogens or a halogen source to the hydrocarbon feed for hydrocracking. See also British Patent 1,106,338.

Preparing Cyclohexane

stamicarbon n.v. British Patent 1,104,275

C6H6 containing more than 0.5 mg/l of S may be successfully hydrogenated in two stages using Pt metal catalysts: in the first stage all S compounds are converted to H2S but only some C6H6 is converted while in the second stage the remaining C6H6 is hydrogenated. Pt/Al2O3 is a suitable catalyst.

Production of Allyl Chloride

farbwerke hoechst a.g. British Patent 1,104,361

Allyl chloride or methallyl chloride is produced by contacting O2 and a mixture of a 3−4C olefin and HCl and/or a 3−4C monochloroparaffin with Ru, Pd, Ir, Pt, or PtO as catalyst.

Preparation of Piperidine

rhone-poulenc s.a. British Patent 1,106,168

Piperidine is produced by reacting glutaric acid or its anhydride with NH3 and H2 at elevated temperature and pressure in the presence of a hydrogenation catalyst. The preferred catalyst is based on Ru, e.g. Ru/C.

Production of Vinyl Acetate

farbwerke hoechst a.g. British Patent 1,106,236

CH3COOH is reacted with C2H4 and O2 in the gaseous phase in the presence of a solid catalyst containing Pd, Pt, Ru, Rh or Ir in elementary form together with a Mn compound on a support.

Production of Metallic Oxide Catalysts

johnson, matthey & co. ltd. British Patent 1,106,814

Electrolytic production of oxides of Pt and/or Pd or oxides of Pt and/or Pd mixed with oxides of other metals not harmful to the catalytic properties of the Pt and/or Pd oxides by electrolysing the appropriate Pt, Pd, Pt alloy or Pd alloy anode in a molten bath of alkali metal halide and nitrate.

Catalyst

ste francaise des produits pour catalyse British Patent 1,107,276

Al2O3 is treated with aqueous solutions of fluoboric and H2PtCl6 in molar proportions of 3.5–4.5 mols fluoboric acid per mol H2PtCl6. The catalyst is especially for catalytic reforming.

Production of Phenols

imperial chemical industries ltd. British Patent 1,108,256

An aromatic compound is oxidised to a phenol using an O2-containing gas in a liquid phase containing HCOOH and a transition metal catalyst, especially Pd, Rh, Ir or other noble metal.

Catalytic Oxidation of Alcohols

imperial chemical industries ltd. British Patent 1,109,228

Primary and secondary aliphatic alcohols are oxidised to aldehydes, ketones and/or acids by contact with O2 in the presence of Ir. The Ir is preferably unsupported and is best precipitated from an iridate or iridite.

Isomerisation of a Hydrocarbon Fraction

shell internationale research mij. n.v. British Patent 1,110,170

Normal paraffins and naphthenes in a 5–7 C hydrocarbon fraction are hydrogenated in the presence of 100–5000 ppm S and a noble metal catalyst composited with a halogenated SiO2 cracking component to bring about isomerisation. The catalyst is preferably Pd or Pt on SiO2 containing F.

Production of Hydrogen Cyanide

e.i. du pont de nemours & co. U.S Patent 3,360,335

Pt and Pt-Rh gauze catalysts, used in the oxidation of an NH3/hydrocarbon mixture, are treated with aqua regia to activate or reactivate the catalyst.

Hydrocracking Process

union oil co. of california U.S. Patent 3,360,458

Feedstocks containing both polycyclic and non-polycyclic hydrocarbons are cracked using a mixture of crystalline zeolite catalyst and an amorphous cogel catalyst, the zeolite containing a higher proportion of Group VIII noble metal catalyst metal. Pt, Pd, Rh and Ir are the preferred metals.

Platinum Metal Catalyst Activation

esso research & engineering co. U.S. Patent 3,360,481

A catalyst consisting of a Pt metal, especially Pd, on a zeolite support is activated using dry H2 at up to 300°F until activation is partly complete and then with wet H2 at a temperature above 300°F.

Cyclohexylamine Production

abbott laboratories U.S. Patent 3,364,261

The reaction of C6H5OH, NH3 and H2 at low pressure is catalysed by Rh metal.

Catalytic Gasoline Reforming

universal oil products co. U.S. Patent 3,365,392

A gasoline is reformed to high octane fuel and LPG by mixing it with H2 and S and passing it at 800−1100°F over a platinised or palladised zeolite.

Hydrogenation of Benzylic Compounds

continental oil co. U.S. Patent 3,366,695

Phenyl carbinol, phenyl alkyl carbinol, phenyl alkyl ketone, benzyl alkyl ethers and benzyl alkanoates are reduced to the corresponding cyclohexyl compounds using a catalyst consisting of a porous support carrying Rh or Ru and promoted with an alkali metal base.

Exhaust Gas Combustion Catalyst

universal oil products co. U.S. Patent 3,367,888

The catalytic activity of noble metal catalysts, e.g. Pt/Al2O3, in burning exhaust gases is promoted by incorporating 0.1−1.5 wt% of thiomalic, thioglycolic or mercaptopropionic acid.

Acyclic Olefin Isomerisation

ethyl corp. U.S. Patent 3,367,988

α-Olefins are isomerised to internal olefins using a Pt metal on an inert support and an alcohol as promoter, e.g. Pd/C and n-octanol.

Cyclododecene Production

geigy chemical corp. U.S. Patent 3,369,052

Cyclododecatriene is selectively reduced to cyclododecene in good yield in the absence of solvent, using H2 and Pd catalyst, e.g. Pd black or PdO.

Packaging System

air products & chemicals inc. U.S. Patent 3,369,859

Traces of O2 in a package filled with inert gas containing H2 are eliminated by catalytic combination on a cylindrical pellet of refractory oxide carrying 0.1−1% Pd or Pt.

Finely Divided Metals

esso research & engineering co. U.S. Patent 3,369,886

Finely divided metals, especially Pt, are obtained by precipitating the metal from its salts while simultaneously precipitating Al(OH)3. The Pt is then freed from Al2O3 with KOH to give a catalyst of high surface area.

Halogen Exchange Process

universal oil products co. U.S. Patent 3,370,096

The exchange of halogen in a hydrocarbon with the halogen of a Friedel-Crafts metal halide in the presence of H2 is catalysed by a Group VIII metal, preferably Pt/Al2O3.

Hydrocarbon Conversion Process

universal oil products co. U.S. Patent 3,371,126

Catalytic reforming with a Pt catalyst, and hydrodealkylation are used to produce aromatic hydrocarbons and town gas.

Platinum Coating and Impregnating Method

johnson, matthey & co. ltd. Dutch Appln. 67.02,039

A PtO2 or a mixture of such an oxide with up to 50% of oxides of Rh, Ru, Ir and/or Pd is reacted with a dispersing medium containing a 2–5 C aliphatic alcohol to form a Pt dispersion. This dispersion is applied to a support and the Pt salted out on to the support. The organic material present is then oxidised and the water expelled.

Selective Catalytic Reduction

johnson, matthey & co. ltd. Italian Patent 787,791

Reduction of a ketone or of an aromatic aldehyde to the corresponding alcohol uses H2 and Pd/charcoal catalyst in the presence of a primary aromatic amine, e.g. C6H5NH2, p -toluidine or benzylamine, or of a heterocyclic tertiary amine, e.g. C5H5N or quinoline.

Mixed Noble/Base Metal Oxide Catalyst

johnson, matthey & co. ltd. Italian Patent 787,819

The catalyst consists of a 3:1 intimate homogeneous mixture of a Pt metal oxide, e.g. oxides of Pt or Pd, with a base metal oxide, e.g. at least one of Fe, Co, Ni, and Cu. The catalyst mixture is prepared by mixing Pt metal and base metal salts and heating or treating them in the presence of a reactant such as NaNO3.

HOMOGENEOUS CATALYSIS

Organosilicon Compositions

dow corning corp. British Patent 1,104,117

A liquid curable system consists of a siloxane, a liquid terminal diene and a catalytic amount of Pt, especially H2PtCl6.

Production of Alkyl Vinyl Ethers

imperial chemical industries ltd. British Patent 1,105,293

In this multistage process, the first stage consists of reacting C2H4 with H2O in the presence of a Pd salt or coordination compound and the usual acetate ions, O2, Cu salt, etc., to give vinyl acetate. In the second stage an identical or similar catalyst (e.g. PdCl2) is used to give the alkyl vinyl ether from the vinyl acetate.

Production of Acetaldehyde

eastman kodak co. British Patent 1,109,483

C2H4 is contacted with an aqueous oxidising composition, at pH 0.5–3.5, containing CuCl2 and a catalytically active Pd compound such as PdCl2 to form a complex which is then hydrolysed.

Producing Vinyl Acetate

asahi kasei k.k.k. British Patent 1,110,663

C2H4, CH3COOH, O2 and a small amount of HCl are reacted in the presence of a catalyst consisting of (a ) Pt, Pd, Rh, Ru, Ir or their chlorides or oxides, hydroxides and salts which readily provide the chlorides of these metals and (b ) Cu, Ag, Zn, Cd, Sn, Pb, Cr, Mo, W, Fe, Ni or their chlorides or oxides, hydroxides and salts which readily provide these metal chlorides.

Lower Saturated Aliphatic Nitriles

asahi kasei k.k.k. British Patent 1,110,687

Lower saturated aliphatic nitriles (especially propionitrile and normal and iso-butyronitrile) are produced by the reaction of C2H4 and/or C3H6 and HCN in catalytic addition at 200−450° in the presence of Pd and/or Rh and/or one of their compounds. See British Patent 1,110,682.

Preparation of Alkenyl Esters

shell oil co. U.S. Patent 3,358,016

Vinyl esters are produced from a 2−4C unsaturated vinylic halide and a Na, Cu or Fe 2−18C monocarboxylate in the presence of DMF, dimethoxyethane and PdCl2 but in the absence of free carboxylic acid.

Redox Catalytic Oxidation of Olefins to Aldehydes and Ketones

union carbide corp. U.S. Patent 3,365,498

The catalyst consists of a Pd, Pt, Ir, Rh, Ru or Au inorganic or organic salt or a diketo complex and a similar compound of a transition metal.

Oxidation of Olefins to Ketones

gulf research & development co. U.S. Patent 3,365,499

A 6−40 C olefin is oxidised by a mixture of a quinone or other oxidising agent and an aprotic solvent with a Pt metal catalyst, e.g. PdCl2.

Hydrogenation of Unsaturated Compounds

shell oil co. U.S. Patent 3,366,646

Non-aromatic C-C unsaturation is hydrogenated over a tris(tertiary phosphine or arsine)rhodium nitrosyl.

Polymerisation of Bicycloheptene Compounds

uniroyal inc. U.S. Patent 3,367,924

Olefins containing a bicyclo (2,2,1)–hept–2–ene ring system are polymerised in aqueous emulsion using a catalyst based on an Ir or Ru compound (e.g. IrCl3) and a reducing agent.

Peroxide-bleaching of Wood Veneers

dr. kurt herberts & co. German Patent 1,259,088

The H2O2 bleaching of wood veneers can be activated by a metal colloid sol, e.g. an ammoniacal Pt sol containing 2.2% Pt. The bleached wood is free from traces of peroxide.

Carbonylation of Olefins and Acetylenes

badische anilin- & soda -fabrik a.g. German Patent 1,261,509

Carbonylation is catalysed by a deacidified solution containing Pd salt complexed with organic phosphine, e.g. bis(tritolylphosphine)PdCl2.

Hydrogenation of Water-Soluble Compounds

johnson, matthey & co. ltd. Belgian Patent 701,238

Dutch Appln. 67.09,685

Certain new hydridopentaminorhodium compounds of formula (HRhX5)++, where X is 5 mols of NH3 or 4 mols of NH3 and 1 mol H2O, are very suitable hydrogenation catalysts, especially for carboxylic acids and other compounds dissolved in H2O.

FUEL CELLS

Catalyst Composition

esso research & engineering co. British Patent 1,108,317

A catalyst for use in electrochemical reaction is made from a mixture of Pt, Re and Ru, each metal being relatively inactive when used alone. The proportions claimed are 40−70% Pt, 1−40% Re and 1−40%Ru, by weight and especially active catalysts are obtained with an atomic ratio of 68.5:15:16.5 (Pt:Re:Ru) where CH3OH is fuel.

Fuel Cells

esso research and engineering co. British Patent 1,108,776

A fuel cell producing current from fuel anodic oxidation, having hydrophobic portions, e.g. Pt black on ptfe, is operated with a fluorocarbon sulphonic or carboxylic acid electrolyte.

Rhodium Catalyst for Fuel Cells

american cyanamid co. U.S. Patent 3,357,863

An inexpensive multimetal H2 fuel cell electrode consists of a mixture of 0−47.5% Pt, 40−95% Rh and 5−20% W oxide, where the amount of Pt is not more than 50% the amount of Rh.

Platinum-Rhodium Fuel Cell Catalyst

american cyanamid co. U.S. Patent 3,357,863

A H2 fuel cell used a four-component catalyst mixture of (a ) 15−35% Pt, (b ) 15−35% Rh, (c ) 5−35% W oxide and (d ) 5−35% Mo oxide.

Platinum Metals in Fuel Cell Electrodes

union carbide corp. U.S. Patent 3,364,074

C-containing electrodes for fuel cells are impregnated with Pt, Pd, Rh or Ir and simultaneously waterproofed by the application of a complex of one of these metals and a suitable diketone, e.g. Pd or Pt acetylacetonate.

CHEMICAL TECHNOLOGY

Mounting of Foils Permeable Only to a Specific Gas

prototech co. British Patent 1,106,876

In order to be able to use thinner, cheaper foils (especially Pd alloy foils permeable to H2), the foil is sinter-bonded to a support of sufficient rigidity which is made of metal at least on the side facing the foil.

Structures Incorporating Thin Metal Membranes

energy conversion ltd. British Patent 1,107,811

H2 permeable membranes, for example, are produced from a perforated support which is bonded to a gas permeable metal or alloy which seals off the holes in the support. Thus in an example a Ni disc is indented on one side, plated on this side with Pd and then Ag and finally abrasive used to remove the projecting material from the reverse side. This leaves holes covered with a Pd-Ag membrane.

Hydrogen Purification Apparatus

t. eguchi et al. U.S. Patent 3,368,329

H2 is purified by diffusion through a bundle of Pd or Pd alloy tubes in a diffusion chamber.

Hydrogen Diffusion Tubes

johnson, matthey & co. ltd. German Patent 1,245,921

A closing plug for sealing the open end of Pd or Pd-Ag alloy H2 diffusion tubes consists of material with approximately the same coefficient of thermal expansion and dimensioned to fit tightly with a projecting, threaded spigot of smaller diameter than the tube and used to form a means for attachment of or for stabilising an internal support for the tube. This corresponds to British Patent 1,009,326.

Hydrogen Diffusion Tubes

johnson, matthey & co. ltd. Dutch Patent 123,628

A diffusion tube used for separation of H2 from gaseous mixtures, made of Pd or of 25 wt.% Ag-Pd, is made more robust and its life is prolonged by incorporating stainless steel or Ni coil springs or metal or ceramic rods as stiffening members to prevent flattening of the tube walls yet permit free passage of gas. This corresponds to British Patent 966,122.

ELECTRICAL AND ELECTRONIC ENGINEERING

Platinum-Platinum Oxide Electrodes

continental oil co. British Patent 1,103,413

Oxide electrodes for detecting corrosive attack are produced by immersing a rod of Pt metal in fused alkali metal nitrate at a temperature of about 400°C and for a period of at least one hour. The oxide layer obtained consists essentially of 3–7 parts monoxide and 1 part dioxide by weight. See also 1,103,414.

Tailoring of Resistors

international business machines corp. British Patent 1,107,788

A film resistor consisting of an oxide semiconductor material with a noble metal additive (e.g. PdO with Au or Ag) is tailored by subjecting a portion of the resistor to electromagnetic radiation to reduce its resistance.

Spark Plugs

robert bosch g.m.b.h. British Patent 1,110,255

A spark plug using less Pt in its construction has a Pt head formed as a plate or disc-like flange which is pressed into the insulator bore so that it deforms and seals the opening of the bore. The opening and the bore portion then form a casting chamber for the remainder of the electrode.

Iridium and Rhodium Semiconductors

american cyanamid co. U.S. Patent 3,356,464

New semiconductors claimed ate IrAsSb, IrPAs, RhAsSb and RhPAs, although the text covers a slightly larger range of compounds such as RhSb2 and IrP. The semiconductors can be used in thermoelectric devices.

Ductile Ruthenium Alloy

international nickel co. ltd. U.S. Patent 3,362,799

Ru powder is mixed with 0.1−25 wt% Re powder and processed in the usual way to give a ductile alloy, e.g. for sparking plugs.

Gold-Palladium Alloy with High Specific Resistance

deutsche gold- & silber-scheideanstalt German Patent 1,262,021

The alloys of German Patent 1,236,207 consisting of 18−75% Au, 75−20% Pd, 2−15% Fe and 0.4−1.2% Al are modified by replacing some or all of the Al by B, Ga and/or In.

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