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Journal Archive

Platinum Metals Rev., 1974, 18, (1), 41

NEW PATENTS: January 1974

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METALS AND ALLOYS

Novel Platinum-Rhodium-Tungsten Alloy

united states atomic energy commission U.S. Patent 3,737,309

A new alloy composition comprising 25−30% Rh, 6−10% W with the remainder Pt, is useful for encapsulating radioisotope fuels. It has a melting point of 1980−2050°C.

Wrought Dispersion Strengthened Metals by Powder Metallurgy

international nickel co. inc. U.S. Patent 3,738,817

Powder metallurgy is used to produce Pt-based alloys by dispersion hardening with uniform distribution of the dispersed agent transversely and longitudinally.

Metal Atomisation

johnson, matthey & co. ltd. French Appl. 2,148,349

Metal articles are produced by arc, flame or plasma spraying metal droplets at a cold target to form a coherent layer of individual particles which are then mechanically worked to a mass. The metal is particularly a Pt-group metal or alloy, e.g. an alloy of 49% Pt, 50% Au and 1% Rh.

Alloy for Metering Instruments

f.a. carl haas German Offen. 2,206,397

Suspension strips for meters are made from Pd and/or Pt containing small amounts of at least one Group III–VI element to increase corrosion resistance and deformability. Au, Ag and Cu may also be present.

CHEMICAL COMPOUNDS

Rhodium Molybdenum Oxide

solvay & cie. British Patent 1,330,589

A new oxide for use as an electrolysis electrode, oxidation catalyst and composite semiconductor is a mixed oxide of formula Rh2MoO6 formed from hydrated rhodium trichloride and molybdic oxide.

Silyl Metal Complexes

dow corning corp. German Offen. 2,260,215

Disilanes and hydrosilanes having Cl substituents are reacted with Pd or Pt phosphine complexes to give silyl complexes of the type Pd(SiPhCl2)(PBu3)2Br.

ELECTRODEPOSITION AND SURFACE COATINGS

Chemical Plating Process

united kingdom atomic energy authority British Patent 1,324,653

Insulators such as glass and plastics are chemically plated by ion bombardment to produce an activated surface which is then contacted with a suitable plating bath. The examples show the use of positive Pd ions for bombardment.

Ruthenium Alloy Electroplating

sel-rex corp. British Patent 1,328,928

Stress in Ru electroplated coatings may be reduced by the co-deposition of another Pt-group metal and optionally a Group IIIB metal such as Ga, In or Ti. The bath used contains 0.5−50 g/l Ru as (NH4)3(Ru2Cl8(H2O)2N) and 0.5−20 g/l of other Pt-group metal as a water-soluble salt, e.g. Na2PtCl6.

Rhodium Plating

american chemical & refining co. inc. U.S. Patent 3,729,396

An aqueous acidic Rh plating bath contains Rh ions, Al ions, SO4 ions and a polycarboxylic organic acid. Optionally PO4 ions are also present.

Electrolyte for Rhodium Deposition

american chemical & refining co. inc. French Appl. 2,150,988

An electrolyte for the deposition of Rh, in the manufacture of jewellery and ornaments, comprises 1.0−30.0 g/l Rh ions, 0.05−5.0 g/l Al ions, 50.0−400.0 g/l sulphate ions and 1.0−25.0 g/l of an organic polyacid, e.g. azelaic, oxalic, maleic acids. The pH is within the range 0.1−2.0. The electrolyte may also include 10.0−70.0 g/l PO4 radicals.

Ruthenium Plating Bath

international nickel ltd. German Offen. 2,261,944

Bright flash coatings of Ru are obtained using baths of pH4 or lower containing a N-bridged Ru complex and at least 1.5 g/l SO4 ion. [Ru2N (H2O)2Cl8]3− is a suitable complex.

HETEROGENEOUS CATALYSIS

Paraffin Hydrocracking and Isomerisation

texaco development corp. British Patent 1,324,480

Control over catalyst activity and selectivity when using fluorided Pt, Pd, Rh, Ru or Re catalysts on Al2O3 supports is achieved by adding an oxide of C.

Organosiloxane Composition

dow corning corp. British Patent 1,324,964

Adhesives are produced from a mixture of organosiloxane and vinyl triacetoxysilane in the presence of a Pd catalyst.

NOx Abatement

johnson, matthey & co. ltd. British Patent 1,330,841

Tail gas from HNO3 plants is mixed with excess CH4 or other gaseous reducing fuel and passed over a layer of Pt-Rh deposited on a wash-coated ceramic honeycomb. The metallic layer contains 20−50% Rh-Pt.

Oxidation of Methane

johnson, matthey & co. ltd. British Patent 1,330,842

A gaseous compound of C is mixed with O2 and passed over a Pt-Rh alloy deposited on a wash coated ceramic honeycomb. The alloy contains 20−50% Rh-Pt. The feed gases may be C-enriched HNO3 tail gases or engine exhaust gases.

Azole Derivatives

merck patent g.m.b.h. British Patent 1,331,408

In the synthesis of azole derivatives the hydrogenation of nitro to amine and the hydrogenolysis of benzyl groups may be catalysed by Pd catalysts.

Benzotriazoles

rhein-chemie rheinau g.m.b.h.

British Patent 1,331,606

Benzotriazoles can be hydrogenated smoothly and rapidly in the presence of Pd, Pt or Rh catalysts to give the hitherto unknown 4, 5, 6, 7-tetrahydrobenzotriazoles in good yields.

Cyclohexanone Production

v.e.b. leuna-werke walter ulbricht British Patent 1,332,211

The hydrogenation of phenol to cyclohexanone is catalysed by an Al2O3-supported mixture of 0.1−5% Pt-group metal and 5−50% alkaline earth metal hydroxide and/or alkaline earth metal oxide. The catalyst must have a specific area of 110 m2/g and at least 40% of the pores in the range 100Å−500Å.

Hydrogenation Catalysts

esso research & engineering co. British Patent 1,332,483

The activity of supported catalysts is increased by treating the supports before impregnation with a Group I–III metal alkyl, aryl, etc. For example 0.6% Pt can be deposited on an alcoholate alumina pretreated with AlEt3.

Hydroformylation

johnson, matthey & co. ltd. British Patent 1,332,894

Catalysts suitable for hydrogenation, hydroformylation and carbonylation may be prepared by absorbing into the pores of a solid porous support solutions of hydrido carbonyl complexes of Rh such as RhH(CO)(PR3)3, RhH(CO)(PR3)2 or RhH(CO)2(PR3)2 where R is an organic substituent.

Methane Production

clarke chapman-john thompson ltd. British Patent 1,333,251

CH4 is produced from CO and H2 in the presence of a Ru, Pt, Co or Ni catalyst, stripped of H2O and then the reaction is repeated to increase the yield.

Paraffin Hydrocracking and/or Isomerisation

texaco development corp. British Patent 1,324,209

Control over temperature and reaction during hydrocracking and/or isomerisation over a Pt/Al2O3 catalyst containing Cl2 is achieved by introducing CO during the reaction.

Lubricating Oils

shell oil co. U.S. Patent 3,730,877

Lubricating oils are produced by the treatment of paraffinic-naphthenic oils with hydrogen over a Pt/Al2O3 catalyst containing up to 4% alkali or alkaline earth metal.

Palladium-Gold Catalyst

knapsack a.g. U.S. Patent 3,743,607

An improved catalyst for the catalytic vapour phase production of CH3COOCHCH2 from C2H4, CH2COOH and O2 is disclosed. A catalyst for the synthesis reaction is metallic Pd and an alkali metal acetate or formate supported on a carrier activated by metallic Au.

Ammonia Oxidation Catalyst

johnson, matthey & co. ltd. French Appl. 2,148,525

Gas reactions, e.g. NH3 oxidation for HNO3 production, are catalysed by two sets of gauzes. The reactant gases first come into contact with noble metal gauzes (e.g. 10% Rh-Pt alloy, and then with less volatile catalytic gauzes such as austenitic 21% Ni, 23% Cr stainless steel or a Pt-Ni-Cr alloy.

Ring Hydrogenation of Arylamides

uniroyal inc. Dutch Appl. 73.02459

N -alicyclic polyamides are produced from N -aryl polyamides by hydrogenation in the presence of a catalyst such as Rh, Ru, Pd, Os, Ir, Ni or Co.

Hydrocarbon Conversion Catalyst

shell internationale research mij. n.v. Dutch Appl. 73.07241

Petrols containing straight chain paraffins are treated to raise the octane number by selective hydrocracking using a catalyst, e.g. Pt deposited on a porous support with a pore diameter of 0.42−0.58 μ and a C content of at least 2.5%, especially a zeolite.

HOMOGENEOUS CATALYSIS

Nitro Compound Reduction

american cyanamid co. U.S. Patent 3,729,512

Nitro compounds are reduced to amines with CO/H2 in the presence of Ru carbonyls or their precursors.

Rhodium Based Catalysts for Diene Synthesis

e. i. du pont de nemours & co. U.S. Patent 3,742,080

Improved catalysts are provided for the synthesis of 1,4-dienes from a-monoolefins and conjugated dienes. The catalysts are Rh(III) salts in combination with amides, phosphoramides, phosphine oxides, or water. The improved catalysts allow control of the trans-cis ratio of the 1,4-diene formed and are operable at useful rates in a wide range of solvent systems, both protonic and aprotic.

Carboxylic Acid or Anhydride Production

monsanto co. Dutch Appl. 73.02968

Carboxylic acids are produced by the reaction of olefins and CO in the presence of an Ir complex of an arsine, phosphine and/or stibine, e.g. HRh(CO)(PPh3)3.

FUEL CELLS

Electrochemical Cells

national research development corp. British Patent 1,332,295

A cell for operating a cardiac pacemaker or the like uses Pt-black in an O2 proof seal as one electrode.

CHEMICAL TECHNOLOGY

Noble Metal Image Stabilisation

polaroid corp. U.S. Patent 3,730,716

Noble metals below Ag in the electromotive series, e.g. Pt-group metal, are used to enhance Ag halide image stability.

Chemical Plating of Fibres

coppertech inc. U.S. Patent 3,733,213

Fibres or fabric are degreased with solvent, oxidised and then sensitised using Pd and Sn solutions.

Silver Halide Grains Sensitised with a Rhodium Salt

eastman kodak co. U.S. Patent 3,737,313

Rh salts are used to sensitise Ag-halide emulsions used in non-destructive testing.

Sensitising Composition

nauchno-issledovatelski technochemicheskii institut German Offen. 2,206,150

Photographic compositions are sensitised with a mixture of organic dyestuff, a water-soluble Pt or Pd salt and a complexing agent.

GLASS TECHNOLOGY

Coating Refractory Metals

johnson, matthey & co. ltd. U.S. Patent 3,736,109

Articles for use at high temperature, for example in the glass industry, have a refractory core made from Nb, Ta, Cr, Zr, V, Hf, Re or their alloys, a barrier layer of MgO and a sheath of a Pt-group metal. The oxides of the core metal or alloy are chosen to be less volatile than the oxides of Mo at operating temperature within the range 1100° to 1500°C.

ELECTRICAL AND ELECTRONIC ENGINEERING

Electric Lamps

thorn electrical industry ltd. British Patent 1,327,363

Heat is conducted away from a lamp seal by the use of a contact cap arrangement having a high thermal conductivity. A Cu sleeve is brazed to Pt-clad Mo conductors by a high Ag-content Cu brazing alloy, which also serves to protect the embedded ends of the conductors from oxidation.

Monolithic Capacitors

n.l. industries inc. British Patent 1,327,902

A fired capacitor has stacked alternating layers of Bi-containing barium titanite and electrode layers, inert to bismuth, consisting of up to 90% Pd with the remainder Au and/or Pt.

Memory Discs

philips electronic & associated industries ltd. British Patent 1,328,016

Improved performance memory discs have a Co-P layer applied to a disc over an intermediate layer of Pt.

Electrical Lead Structures

international standard electric corp. British Patent 1,329,050

External leads on vidicon tubes are eliminated by placing the leads, e.g. of Pt, in grooves formed internally in the envelope and then sealing with a melted glass frit.

Circuit Patterns

western electric co. inc. British Patent 1,329,287

A layer between a circuit pattern and the substrate has a discontinuous, etch resistant portion of Pd which is highly adherent to the base. A thicker layer of easily etched material, such as Au, Cu or Ni is then applied. The resulting composite has good adhesion and can be easily etched.

Electroless Deposition

r.c.a. corporation British Patent 1,332,000

An apertured colour TV selection mask is produced by first depositing a pattern of catalytic material such as Pd and then depositing enough metal chemically on the pattern to form the opaque pattern required.

Sandwiched Eutectic Reaction Anticompromise Circuits

u.s. secretary of the navy U.S. Patent 3,745,227

An anticompromise circuit has a thin film circuit sandwiched between two eutectic reaction films separated by electrical insulating films. The eutectic reaction films consist of a mixture of Pd and Al and are adapted to be coupled to a switched electrical source to produce a eutectic reaction to destroy the thin film circuit.

Schottky Diode

signetics corp. German Offen. 2,264,322

A Schottky diode is produced by the application of a Pt-Ni-Si alloy layer to a Si block.

Grid Electrodes

brown, boveri & cie. Dutch Appl. 72.17592

Grid electrodes for discharge tubes have an intermetallic layer, such as ZrPt3, coated with a noble metal layer such as Pt.

TEMPERATURE MEASUREMENT

Platinum Resistance Temperature Sensors

rosemount eng. co. ltd. British Patent 1,325,451

A Pt resistance temperature sensor is described which does not deteriorate in stability, provided that the pressure is prevented from rising substantially within the sheath.

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