Atomic Energy of Canada Limited

John H Rolston

John P Butler

Fred W Molson

James Den Hartog

Linda M Paterson

John W Goodale

Sieghard E Wanke

William H Stevens

James Denhartog

Ivo G Dalla Lana

Fred D Otto

Huseni A Rangwala

Edward A Symons

Michel J Clermont

A crystalline, silica platinum catalyst structure is provided by soaking a hydrophobic, high surface area, crystalline silica (SiO.sub.2) lattice essentially free of aluminum oxide in the SiO.sub.2 lattice, such as silicalite in an aqueous solution of Pt(NH.sub.3).sub.4 Cl.sub.2 and then, drying, reducing and cooling the crystalline silica to leave, catalyst crystallites of platinum on the crystalline silica and in the pores thereof, and then providing an outer, porous, membrane coating of high molecular weight, organic polytetrafluoroethylene, polymeric material on the coated crystallites. The platinized, crystalline silica may be slurried with, polytetrafluoroethylene and a ceramic support coated with the slurry, so that a water repellent, water vapor and hydrogen or oxygen gas permeable, polytetrafluoroethylene matrix is provided on the support with the platinized, crystalline silica dispersed in the matrix. The catalyst has a high platinum content and high platinum dispersion and is particularly useful for hydrogen isotope exchange between liquid water and gaseous hydrogen or for such exothermic reactions as combining hydrogen and oxygen.

Method of manufacturing a crystalline silica/platinum catalyst structure

Hydrogen isotope (e.g. deuterium) exchange from liquid water to a gaseous halohydrocarbon (e.g. fluoroform, CF.sub.3 H--CF.sub.3 D) is obtained at an operating temperature in the range 0.degree. to 100.degree. C. using a catalytically active mass comprising a porous anion exchange resin in the hydroxide ion form and enriched gaseous halohydrocarbon stream is decomposed by isotope selective photo-decomposition into a first, gaseous stream enriched in the hydrogen isotope, which is removed as a product, and a depleted gaseous halohydrocarbon stream, which is recirculated for enrichment again. The catalytically active mass may, for example, be in the form of resin particles suspended in a fluidized bed or packed as resin particles between sheets wound into a roll. One of the sheets may be corrugated and have open interstices to form a packing in a column which permits countercurrent gas and liquid flow past the resin. Preferably the wound sheets are hydrophilic to retard flooding by the liquid water. The liquid water stream may contain dimethyl sulfoxide (DMSO) added as co-solvent.

Process for the exchange of hydrogen isotopes between streams of liquid

For the exchange of hydrogen isotopes between streams of gaseous hydrogen and liquid water, wherein the streams are at a temperature in the range 273 to 573K are brought into contact with one another and a catalytically active mass, an improved catalytically active mass is provided comprising an inherently hydrophotic, porous, polytetrafluoroethylene matrix and partially platinized carbon particles dispersed throughout the whole of the porous polytetrafluoroethylene matrix in the weight ratio of 1:1 to 3:1 of polytetrafluoroethylene to partially platinized high surface area carbon particles. The inherently hydrophobic, porous, polytetrafluoroethylene matrix allows the catalytically active metal to catalyze the hydrogen isotope exchange reaction between hydrogen gas and water vapor in the presence of liquid water while retarding loss of activity of the catalytically active metal by contact of the metal catalyst with liquid water. This catalyzed chemical isotope exchange proceeds simultaneously with isotope exchange from water vapor to liquid water by a non-catalyzed, physical evaporation and condensation exchange reaction. The efficient coupling of these two isotopic transfer steps which results in a rapid overall isotopic exchange between hydrogen and liquid water without a pronounced loss of activity of the catalytically active mass is dependent upon the weight ratio of the catalytically active platinized carbon to the polytetrafluoroethylene matrix being in the above mentioned range of 1:1 to 3:1.

Catalytically active mass for the exchange of hydrogen isotopes between

A process for the exchange of hydrogen isotopes between streams of gaseous hydrogen and liquid water is described, wherein the streams at a temperature in the range 273 to 573 K are brought into contact with one another and a catalytically active mass comprising an inherently hydrophobic, porous, polytetrafluoroethylene matrix and partially platinized carbon particles dispersed throughout the whole of the porous polytetrafluoroethylene matrix in the weight ratio of 1:1 to 3:1 of polytetrafluoroethylene to partially platinized high surface area carbon particles. The inherently hydrophobic, porous polytetrafluoroethylene matrix allows the catalytically active metal to catalyze the hydrogen isotope exchange reaction between hydrogen gas and water vapor in the presence of liquid water while retarding loss of activity of the catalytically active metal by contact of the metal catalyst with liquid water. This catalyzed chemical isotope exchange proceeds simultaneously with isotope exchange from water vapor to liquid water by a non-catalyzed, physical evaporation and condensation exchange reaction. The efficient coupling of these two isotopic transfer steps which results in a rapid overall isotopic exchange between hydrogen and liquid water without a pronounced loss of activity of the catalyst is dependent upon the weight ratio of the catalytically active platinized carbon to the polytetrafluoroethylene matrix being in the above mentioned range of 1:1 to 3:1.

Process for the exchange of hydrogen isotopes between streams of gaseous

A process for the exchange of hydrogen isotopes between streams of gaseous hydrogen and liquid water, wherein the streams are brought into contact with one another and a catalyst assembly at a temperature in the range 0.degree.-300.degree. C. The catalyst is an inherently hydrophobic material such as polytetrafluoroethylene, polyethylene, polystyrene, polymethacrylate, polypropylene or carbon black carrying a catalytically active metal, for example, platinum, rhodium and nickel. The inherently hydrophobic support allows the catalytically active metal to catalyze the hydrogen isotope exchange reaction between hydrogen gas and water vapor in the presence of liquid water while retarding loss of activity of the catalytically active metal by contact of the metal catalyst with liquid water. This catalyzed chemical isotope exchange proceeds simultaneously with isotope exchange from water vapor to liquid water by a non-catalyzed, physical evaporation and condensation exchange reaction to effect an overall rapid catalytic isotopic exchange between streams of hydrogen gas and liquid water.

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Deep River, Canada

John H Rolston