Abstract: The invention concerns a method for regenerating a working solution for producing hydrogen peroxide 30%, in which the working solution is contacted with alumina at a temperature of approximately 40-160.degree. C.

Abstract: The invention features a method for treating a supported catalyst with a sulphur compound based active phase and a mercury compound contaminated mineral support. This method consists in implementing the following steps: the said catalyst is contacted with a basic aqueous solution of at least one sulphide selected among alkaline metal sulphides, alkaline-earth metal sulphides or ammonium sulphide; then the catalyst is separated from the basic aqueous solution. At the end of this process, the treated catalyst shows the same characteristics as before its contamination by mercury.

Abstract: Spent lead catalysts containing contaminating amounts of arsenic values, e.g., mixed oxides of lead and arsenic, are regenerated and rendered suitable for reuse by heat-treating same at a temperature of at least 550.degree. C. in the presence of a gas mixture which comprises an inert gas, e.g., Ar, N.sub.2 or He, and at least 2% by volume of at least one reducing gas, e.g., H.sub.2, CO or CH.sub.4.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.