Platinum Metals Rev., 1973, 17, (4), 155
NEW PATENTS: October 1973
METALS AND ALLOYS
Hydrogen Diffusion Membranes
n. r. d. c. U.S. Patent 3,713,270
H2 is separated from gas mixtures using membranes made from an alloy of Pd with lanthanides, (not La or Pr), e.g. 8·5%Y–Pd or 10%Ce–Pd.
comptoir lyon-alemand louyot&cie. French Patent 2,133,178
Spinnerets for synthetic fibre production are made from an alloy of 80.5−90% Au, 10−19.5% Pt and 0−3% of at least one of Rh, Ir, Ru, Os and Re.
Platinum Group Metal Cladding
philip morris inc. British Patent 1,318,713
Electrochemical cells using a fluoride electrolyte have Au or Pt metal cathodes.
Hydrogen Absorption in Electrochemical Cells
union carbide corp. British Patent 1,321,853
Pd is used with MnO2 in a binder to form a device absorbing and oxidising H2.
p.p.g. industries inc. British Patent 1,323,756
Electrolysis electrodes have a Ti or similar metal base plated with a Pt group metal from an organic bath containing a highly ionisable electrolyte. A typical bath contains 0.78g H2PtCl6, 75ml absolute EtOH, 15 ml H2SO4, 20 ml toluene and 20 ml acetone.
p.p.g. industries inc. U.S. Patent 3,718,551
The electrolysis of brines is effected with a Ti base electrode coated with a mixture of amorphous TiO2 and Ru or RuO2.
ELECTRODEPOSITION AND SURFACE COATINGS
international nickel ltd. British Patent 1,322,175
Os is electroplated at a temperature of at least 50°C from a hexachlorosmate bath (preferably (NH4)2OsCl6) containing sulphamic or sulphuric acid to give a pH of 0–4.
LABORATORY APPARATUS AND TECHNIQUES
esso research&engineering co. British Patent 1,320,954
A gas stream containing a low concentration of hydrocarbons is analysed by passing it over a heated noble metal or noble metal alloy wire whose heating voltage is sequentially varied. A Pt or Pd wire is preferred.
Oxygen Control Cell
Hydrocarbon Conversion Catalyst
universal oil products co. British Patent 1,323,913
An exceptionally active and resistant catalyst for hydrocarbon conversion contains Pt, Sn and Ge on a support. In one example 0.2% Ge, 0.375% Sn and 0.375% Pt are used on an Al2O3 carrier.
Motor Fuel Production
sun oil co. of pennsylvania U.S. Patent 3,719,586
Light naphtha is reformed, mixed with heavy naphtha and then hydrocracked over a Pd-zeolite catalyst to yield a motor fuel.
Exhaust Gas Catalysts
esso research&engineering co. U.S. Patent 3,719,739
Nitrogen oxides are removed from engine exhaust gases over catalysts consisting of 10−60% Ir and 40−90% Ru, as metals and/or oxides, on a conductive support such as stainless steel or chromium steel.
f.c. wilhelm U.S. Patent 3,725,304
A Pt-Sn catalyst for hydrocarbon conversion is obtained by impregnating Al2O3 or another support with a trichlorostannate chloroplatinate anionic complex and calcining.
Phthalic Acid Purification
standard oil co. U.S. Patent 3,726,915
The alloying of Cu with Pd on C in a Cu:Pd ratio of less than 0.5:1 enhances the activity of the Pd when used for reduction purposes, especially the selective reduction of formyl benzoic acid in crude phthalic acid.
cie. franÇaise de raffinage French Patent 2,130,881
A new hydrorefining catalyst contains 0.02−2% Pt, 0.02−2% Ir and 0.02−2% Sn on a support.
johnson matthey&co. ltd. French Appl. 2,140,599
A graphite or carbon article is purged with a gaseous fluid and is then impregnated using a solution or suspension of an Ru compound or metallic Ru in a solvent which is then evaporated.
johnson matthey&co. ltd. German Offen. 2,231,296
A core of inert material such as a ceramic is coated with an intermediate layer containing a rare-earth oxide, and then with a mixture of alloy of Pt, Rh and optionally a base metal. The Rh represents 1−50% and the base metal, if present, 0.01−25% of the total metal. The catalyst can be used for hydrocarbon oxidation and nitrogen oxide reduction reactions.
NOx Removal Catalyst
ford-werke a.g. German Offen. 2,241,582
Nitrogen oxides are removed from I.C.E. exhaust gases over a Pt and/or Pd catalyst which also oxidises CO and unburnt hydrocarbons.
Catalyst for Nitric Acid Production
deutsche gold&silber-scheideanstalt German Offen. 2,145,842
HNO3 is produced from NH3 by oxidation over a fine gauze consisting of 40−75% Pd, 1−8% Rh and/or Ru, remainder Pt.
johnson matthey&co. ltd. German Offen. 2,248,811
A support suitable for a Pt catalyst consists of a layer of heat resistant cord made from compressed tube or gauze, which has a substantially uniform thickness and at least one flat surface, attached to a gauze plate.
ford-werke a.g. German Offen. 2,251,615
Nitrogen oxides are reduced in a first catalyst zone and then the products are passed over an Ru catalyst to remove any NH3 present.
NOx Removal Catalyst
johnson matthey&co. ltd. German Offen. 2,253,070
Nitrogen oxides are removed from exhaust gases over a catalytic mixture of 5−75% Ru, 0−30% base metal and remainder (not less than 5%) Pt on a suitable support. Examples of base metals which may be present are Co, Ni, V, Fe, Cr and Re. This is equivalent to Dutch Appl. 72.14540.
johnson matthey&co. ltd. German Offen. 2,256,195
An oxidation-reduction catalyst consists of an alloy or mixture of 5−55% Ru, 1−20% Rh, 0−20% base metal and remainder Pt. This is equivalent to Dutch Appl. 72.15560.
johnson matthey&co. ltd. German Offen. 2,257,228
An oxidation-reduction catalyst, e.g. for treating I.C.E. exhaust gases, consists of an inert carrier such as zircon-mullite carrying a mixture of Pt and Rh, the Rh representing up to 20% of the total metal. This is equivalent to Dutch Appl. 72.15719.
Catalytic Exhaust Gas Treatment
Ethylene Dicarboxylic Acid
denki kagaku kogyo k.k. British Patent 1,323,619
Acetylene and CO are reacted to give ethylene dicarboxylic acid in the presence of a Pd salt of a strong acid, an amino acid and a solvent.
Polynuclear Aromatic Compounds
hughes aircraft co. British Patent 1,314,238
Pd p -toluene sulphonate is a suitable nucleation-inducing compound in a nucleating medium for photographic purposes.
Flame Retardants for Elastomers
general electric co. U.S. Patent 3,711,520
The fire resistance of a silicone elastomer stock is improved by adding Pt or Pt compounds and a Group II metal oxide. In an example the Pt source added is a reaction product of chloroplatinic acid and a tetravinyl tetramethyl cyclotetrasiloxane.
Photoreducible Palladium Compounds
eastman kodak co. U.S. Patent 3,719,490
Physical development of Ag latent images is catalysed by light sensitive Pd compounds able to generate metal nuclei. These compounds have the formula (PdLx)yAz. Where L is a halogen, carboxylic acid, aryl, N, As, Sb or P ligand, A is H, anion or metal cation, x is 0–4, y is 1–4 and z is 0–2, e.g. potassium palladium oxalate.
Rhodium in Silver Halide Emulsions
Platinum in Optical Glass Filters
v.e.b. jenaer glaswerk schott&gen. British Patent 1,317,395
About 0.0001–0.01 at.% Pt is added to glass for optical filters to provide centres for crystallites.
ELECTRICAL AND ELECTRONIC ENGINEERING
plessey co. ltd. British Patent 1,317,494
A capacitor has a cathode of inert material coated on the face wetted by the electrolyte with a Pt group metal paint. A ceramic paint containing Pt and Ir or Au and Pd is suggested.
Thick Film Resistors
r.c.a. corp. British Patent 1,320,625
The resistivity of screen printed resistors produced using Ag-Pd is adjusted by allowing a certain dwell time at room temperature between printing and firing.
r.c.a. corp. British Patent 1,321,034
An intermetallic contact is produced in an opening on a semiconductor by applying a metal such as Pt, Pd or Rh which is able to alloy with the semiconductor.
western electric co. inc. British Patent 1,323,828
Avalanche breakdown is avoided by using a Pt Schottky barrier with extensive overhang.
r.c.a. corp. U.S. Patent 3,714,521
W semiconductor interconnections are coated with Pt where leads are to be attached.
general electric co. U.S. Patent 3,717,503
The electron emission of a cathode is increased selectively by placing a control grid above the cathode and evaporating Os or Ir through the openings on to the cathode.
Magnetic Recording Medium
fuji photo film co. ltd. U.S. Patent 3,717,504
A magnetic recording medium has a magnetisable surface layer coated with thin Ni and Rh layers.
Palladium Circuits in Alumina
american lava corp. U.S. Patent 3,723,176
A green sheet is produced from prefired Al2O3. This is screen printed with a circuit using a Pd ink. The circuit is covered with more Al2O3 and contacts provided. The second layer of Al2O3 is also screen printed with a Pd ink and the whole unit fired.
westinghouse electric corp. U.S. Patent 3,727,091
An electric lamp containing halogen has a Pt-coated Ni or nichrome fuse wire.