Procatalyse

Rhone-Poulenc Chimie

Rhone-Poulenc Industries

Societe Francaise Des Produits Pour Catalyse 'Procatalyse'

Jean-Pierre Brunelle

Michel Prigent

Gilbert Blanchard

Philippe Courty

Eric Quemere

Emmanuel Goldenberg

Patrice Nortier

Richard Doziere

Bernard Raynal

The desulfurization of industrial gases by the catalytic conversion of contaminating sulfur values therein, comprising, e.g., either Claus process or hydrolysis of organosulfur compounds, is carried out in the presence of an effective amount of a cerium oxide-based catalyst.

CeO catalytic desulfurization of industrial gases

A pollution control catalyst for a catalytic converter in the exhaust system of an internal combustion engine, which catalyst comprises a support impregnated with (i) at least one platinum group precious metal, and with (ii) cerium base metal, or a combination of cerium and at least one other base metal, is facilely prepared by (1) impregnating a catalyst support with precursor compounds of said cerium base metal, or of said cerium base metal and of at least one other base metal, (2) activating said impregnated support, under a neutral or oxidizing atmosphere, at a temperature ranging from 120.degree. to 800.degree. C., (3) impregnating said catalyst support with precursor compounds of said at least one platinum group precious metal, together with a delayed-action organic reducing agent, inactive under cold conditions, which effects reduction of said platinum group precious metal precursor compounds, but not of any cerium or other base metal precursor compounds, under the conditions of the step (4) below, and (4) activating said impregnated catalyst, also under a neutral or oxidizing atmosphere, at a temperature ranging from 300.degree. to 800.degree. C.

Process for the preparation of a pollution control catalyst for internal

Provided is an improved catalyst and a process employing same in the treatment of exhaust gases generated by internal combustion engines. The catalyst comprises a support and an active phase comprising copper, cerium and/or iron, at least one metal selected from the group consisting of platinum and palladium, and at least one metal selected from the group consisting of iridium and rhodium. The catalyst is particularly active in the removal of carbon monoxide, unburned hydrocarbons and nitrogen oxides generally present in the exhaust gases of an internal combustion engine.

Catalyst and use thereof in treating internal combustion engine exhaust

A pollution control catalyst for a catalytic converter within the exhaust system of an internal combustion engine is facilely prepared by (i) coating/impregnating a catalyst support with palladium and at least one base metal catalyst, (ii) activating the step (i) catalyst, (iii) next coating/impregnating the step (ii) activated catalyst with at least one platinum group precious metal other than palladium, or combination of palladium and at least one other platinum group precious metal, and (iv) then activating the step (iii) catalyst.

Pollution control catalyst for internal combustion engine exhaust

The exhaust gases from internal combustion engines are catalytically oxidized/reduced, to remove CO, unburned hydrocarbons and NO.sub.x therefrom, utilizing an improved stable and long-lived catalyst which comprises (1) a support substrate, e.g., a monolithic or particulate support, and (2) an active phase deposited thereon, said active phase (2) comprising (i) cerium, (ii) iron, (iii) at least one of the metals gallium and/or yttrium, (iv) at least one of the metals platinum and/or palladium, and (v) at least one of the metals iridium and/or rhodium.

Catalyst for treatment of exhaust gases from internal combustion engines

A pollution control catalyst for a catalytic converter comprising the exhaust system of an internal combustion engine, said catalyst including a refractory oxide support, and an activated phase therefor comprised of 0.3 to 7% by weight cerium based upon the weight of said support, 0.1 to 3.5% by weight iron, also based upon the weight of said support, at least one platinum or palladium metal, and at least one iridium or rhodium metal.

A non-polluting oxyhydrochlorination process is provided in which the residual gaseous effluents are purified by catalytic oxidation in the presence of a catalyst comprising platinum and/or iridium deposited on a special alumina support of eta crystallographic structure and then washing the effluent before being discharged into the atmosphere. The process of the invention is particularly applicable to a residual effluent containing essentially carbon monoxide, carbon dioxide, ethylene, 1,2-dichloroethane, and at least one chlorinated hydrocarbon from among the group consisting of chloroform, carbon tetrachloride, ethyl chloride, 1,1-dichloroethane, 1,1,1- and 1,1,]-trichloroethanes, 1,1,2,2- and 1,1,1,2- tetrachloroethanes, vinyl chloride, 1,1- and 1,2-dichloroethylenes, trichloroethylene, perchloroethylene and chloral.

Non-polluting oxyhydrochlorination process

A process for hydrodealkylating alkyl-substituted aromatic hydrocarbons, e.g., toluene, by reaction with hydrogen in the absence of water vapor under relatively mild reaction conditions, and a catalyst therefor are disclosed. The process is effected at a temperature of from about 450.degree. to 650.degree. C., preferably from about 520.degree. to 620.degree. C., and pressures of from about 1 to about 30, preferably from about 5 to about 20 bar, and a liquid hourly space velocity of from about 1 to about 10, preferably from about 3 to about 8, in the presence of a catalyst which comprises a noble metal component comprising rhodium and a support comprising a metal aluminate having a spinel structure and corresponding to the empirical formula M Al.sub.2 O.sub.4.X Al.sub.2 O.sub.3, wherein X represents a value of from 0 to about 200 and M represents a metal selected from the group consisting of nickel, cobalt, copper, zinc, iron, and magnesium. Preferably, the support comprises an active alumina bearing a surface layer of said aluminate.

Hydrodealkylation of alkylaromatic hydrocarbons

A process for hydrodealkylating alkyl-substituted aromatic hydrocarbons, e.g., toluene, by reaction with hydrogen in the absence of water vapor under relatively mild reaction conditions, and a catalyst therefor are disclosed. The process is effected at a temperature of from about 450.degree. and 650.degree. C., preferably from about 520.degree. to 620.degree. C., and pressures of from about 1 to about 30, preferably from about 5 to about 20 bar, and a liquid hourly space velocity of from about 1 to about 10, preferably from about 3 to about 8, in the presence of a catalyst which comprises a metal combination of rhodium and at least one metal selected from the group consisting of copper, nickel, cobalt, iron, and zinc, and a support comprising activated alumina having a specific surface of between about 100 and about 350 m.sup.2 /g and a total pore volume of from about 0.5 to about 0.8 cm.sup.3 /g. The activated alumina support may comprise agglomerates of active alumina obtainable by dehydrating alumina hydrate in a stream of hot gas. The agglomerates also may be previously autoclaved in an acid or neutral aqueous medium.

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Saint-Brice sous Foret, France

Jean-Pierre Brunelle