Abstract: Hydrotreating catalyst containing one or more metal oxides and/or sulphides selected from Group VI-B and Group VIII of the Periodic Table supported on a porous refractory carrier, wherein the catalyst being in form of an angular extrudate with rounded edges.

Abstract: A presulfurization method of hydrogenation catalyst comprises mixing an olefin-containing component, elemental sulfur and a promoter, heating the resultant mixture at 100-120° C. for more than 0.5 hours, wherein the mole number of elemental sulfur is at least not less than that of double bonds of the olefin, and the amount of the promoter used is 10-80% weight of the amount used of elemental sulfur, and said promoter is selected from an organic promoter used usually in rubber curing; the elemental sulfur-incorporated catalyst is impregnated with the product obtained, and heated at 100-300° C. in an inert atmosphere for more than 1 hour; wherein the volume amount of said product used is at least 60% of the pore volume of the catalyst. In the case of a little amount of the promoter being used, the presulfurization method can improve greatly the sulfur retention degree of the catalyst.

Abstract: The invention relates to a novel rhodium sulfide catalyst for the reduction of oxygen in industrial electrolyzers. The catalyst is highly resistant towards corrosion and poisoning by organic species, thus resulting particularly suitable for use in aqueous hydrochloric acid electrolysis, when technical grade acid containing organic contaminants is employed.

Abstract: The present invention pertains to a process for sulfiding a catalyst composition comprising at least one hydrogenation metal component of Group VI and/or Group VIII of the Periodic Table, and an organic additive wherein the catalyst composition is first contacted with an organic liquid, followed by the catalyst being contacted with hydrogen and a sulfur-containing compound in the gaseous phase, wherein less than about 40%, preferably less than about 35%, more preferably less than about 25%, most preferably less than about 15%, of the sulfur present in the sulfided catalyst is added with the organic liquid. The process of the present invention makes it possible to use additive-containing catalysts without loss of activity in units which cannot effect gas phase start-up or are required to carry out a pressure test. The organic liquid may be a hydrocarbon with a boiling range of about 150-500° C., preferably gasoline, white spirit, diesel, gas oil, mineral lube oil, or white oil.

Abstract: The present invention pertains to a process for sulfiding a catalyst composition comprising at least one hydrogenation metal component of Group VI and/or Group VIII of the Periodic Table, and an S-containing organic additive wherein the catalyst composition is first contacted with an organic liquid, followed by the catalyst being contacted with hydrogen and a sulfur-containing compound in the gaseous phase. The invention also pertains to the sulfided catalyst composition and its use in hydrotreating. Catalysts sulfided by the process according to the invention show a higher activity than the same catalysts which have not been sulfided. It is preferred to carry out the process according to the invention ex situ, where it solves the problem of difficult start-up and the formation of undesirable side products in the hydrotreating unit. The organic liquid may be a hydrocarbon with a boiling range of about 150-500° C., preferably white oil, gasoline, diesel, gas oil, or mineral lube oil.

Abstract: The present invention pertains to a process for sulfiding a catalyst composition comprising at least one hydrogenation metal component of Group VI and/or Group VIII of the Periodic Table, and an S-containing organic additive wherein the catalyst composition is contacted with hydrogen and a sulfur-containing compound in the gaseous phase, characterized in that the process is carried out ex situ. By carrying out the process ex situ, the formation of undesirable side compounds in the hydrotreating unit is prevented. Additionally, the reactor suffers less downtime, and the start-up of the reactor may be simplified. The S-containing organic additive preferably is a mercapto-compound, more preferably a mercaptocarboxylic acid represented by the general formula HS—R1-COOR, wherein R1 stands for a divalent hydrocarbon group with 1-about 10 carbon atoms and R stands for a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or a linear or branched alkyl group having 1 to about 10 carbon atoms.

Abstract: The present invention relates to a shaped solid acid catalyst for the isomerization of hydrocarbons and so on, which has a high activity and is excellent in strength and easily handleable, and processes for the preparation thereof. This catalyst comprises a support comprising portions of zirconia having a tetragonal form and portions of alumina, and a sulfureous component and, if necessary, a Group 8, 9 or 10 metal component both being supported on the support, and has a specific surface area of 150 m2/g or above. The catalyst can be prepared by kneading aluminum hydroxide, zirconium hydroxide and a sulfureous compound, shaping the kneaded mixture, calcining the shaped material at such a temperature as to form tetragonal zirconia and, if necessary, supporting a Group 8, 9 or 10 metal component on the calcined material and calcining the resulting molding at 300 to 700° C.

Abstract: The invention concerns a process for sulphurizing supported catalysts containing at least one element selected from group IIIB, including the lanthanides and actinides, group IVB, group VB and group VIB, said process being characterized in that said catalyst is pre-reduced with at least one reducing gas other than hydrogen before sulphurizing said catalyst. The invention also concerns the sulfide catalysts obtained by the process of the present invention as well as the use of the sulfide catalyst in a process for hydrocracking and hydrotreatment of hydrocarbon-containing feeds.

Abstract: For the presulphurization of catalysts based on metal oxides, intended especially for the hydrotreating of hydrocarbon feedstocks, at least one tertiary mercaptan (for example tert-dodecyl mercaptan) is employed as sulphurizing agent. This tertiary mercaptan can be employed alone or combined with another sulphur-donor compound. The presulphurization according to the invention may be carried out in situ or ex situ.

Abstract: In a process for preparing a catalyst comprising at least one support, at least one metal from group VIII of the periodic table and at least one additional element M selected from the group formed by germanium, tin, lead, rhenium, gallium, indium and thallium, metal M is introduced in an aqueous solvent in the form of at least one organometalic compound comprising at least one carbon-M bond.

Abstract: An exhaust-gas-purifying catalyst is made by depositing on a support iridium serving as a catalyst active substance, sulfur for improving the catalyst activity of iridium and, if necessary, platinum. The sulfur is preferably contained as a sulfate. The exhaust-gas-purifying process of the present invention is a process in which exhaust gas from an internal combustion engine is allowed to pass through the exhaust-gas-purifying catalyst with the exhaust-gas temperature being set in the range of 200° C. to 700° C. at the inlet of the exhaust-gas-purifying catalyst. The above-mentioned composition and process provide an activity for purifying exhaust gas, especially for eliminating nitrogen oxides in an oxidizing atmosphere, in a wide temperature range, allow high heat-resistance and durability, and consequently, are superior in practical use.

Abstract: A catalytic converter for cleaning exhaust gas includes a heat-resistant support, and a catalytic coating formed on the heat-resistant support. The catalytic coating contains Pd-carrying particles of a cerium complex oxide, Pt & Rh-carrying particles of zirconium complex oxide, and particles of a heat-resistant inorganic oxide.

Abstract: The invention concerns a process for sulphurising supported catalysts containing at least one element selected from group IIIB, including the lanthanides and actinides, group IVB and group VB, said process being characterized in that said catalyst is sulphurised using a mixture containing at least one source of elemental sulphur and at least one source of carbon in an autogenous or inert atmosphere. Also disclosed are sulphurised catalysts obtained by the process of the invention, the use of the catalysts in processes for hydrocracking and hydrotreatment of hydrocarbon-containing feeds.

Abstract: An exhaust-gas-purifying catalyst is made by depositing on a support iridium serving as a catalyst active substance, sulfur for improving the catalyst activity of iridium and, if necessary, platinum. The sulfur is preferably contained as a sulfate. The exhaust-gas-purifying process of the present invention is a process in which exhaust gas from an internal combustion engine is allowed to pass through the exhaust-gas-purifying catalyst with the exhaust-gas temperature being set in the range of 200° C. to 700° C. at the inlet of the exhaust-gas-purifying catalyst. The above-mentioned composition and process provide an activity for purifying exhaust gas, especially for eliminating nitrogen oxides in an oxidizing atmosphere, in a wide temperature range, allow high heat-resistance and durability, and consequently, are superior in practical use.

Abstract: The invention relates to an acid catalyst containing a substantial quantity of supported or mass sulfated zirconia and at least one hydrogenating transition metal. This catalyst is characterized by the fact that the sulfated zirconia is in crystallized form and that it shows a specific surface area greater than or equal to 150 m2/g, a pore volume greater than or equal to 0.20 cm3/g and an average pore diameter greater than or equal to 20 Angstroms (20×10−10 m). The invention also relates to methods of making this catalyst and to the uses of this catalyst in hydrocarbon transformation chemical reactions requiring the use of an acid type catalyst, such as for example, isomerization, alkylation, oligomerization reactions or even light hydrocarbon dehydration reactions, and also heavier hydrocarbon hydrocracking and hydroisomerization reactions.

Abstract: Solid superacid catalysts, in the form of spheres or microspheres, consisting of a mixed sulfated oxide of zirconium and of at least one other element selected from those of group 3, group 4, group 5, group 6, group 7, group 8 group 9, group 10, group 11, group 12, group 13, group 14, group 15 and those of the series of lanthanides, alone or combined with each other, are characterized in that they are obtained by means of a sol-gel process comprising the following steps: preparing a zirconium sol, mixed with a thickening agent and optionally with the element or elements selected; adding, only when microspheres are to be obtained, a non-ionic surface-active agent, to the sol; dripping, obtaining spheres, or atomising, obtaining microspheres, the sol into a basic gelation bath; ageing the spheres or microspheres of gel thus obtained; washing the spheres or microspheres with water up to pH=9; and draining them without drying them; impregnating the spheres or microspheres of gel with an aqueous soluti

Abstract: The oxidation catalyst system of the invention is composed of (A) a ruthenium compound and (B) a dioxybenzene or its oxidant. The ruthenium compound (A) includes dichlorotris(triphenylphosphine)ruthenium (II) and other ruthenium complexes and Ru/C. The dioxybenzene or its oxidant (B) includes hydroquinone. The oxidation of an alcohol by molecular oxygen in the presence of the oxidation catalyst system can give the corresponding carbonyl compound in high yield. A primary alcohol is more selectively oxidized than a secondary alcohol.

Abstract: The invention relates to a novel rhodium sulfide catalyst for the reduction of oxygen in industrial electrolyzers. The catalyst is highly resistant towards corrosion and poisoning by organic species, thus resulting particularly suitable for use in aqueous hydrochloric acid electrolysis, when technical grade acid containing organic contaminants is employed.

Abstract: A catalyst system, in particular for carrying out cross-coupling reactions is obtainable by reactinga) a palladium(II) compound withb) a water-soluble phosphine ligand andc) a sulfoxide or polyhydric alcohol.

Abstract: A catalyst for exhaust gas purification characterized by high catalytic activity, heat resistance, and toxin resistance includes a metal oxide and at least one alkali metal sulfate or at least one alkaline earth metal sulfate. The process for producing the catalyst includes mixing the metal oxide with an aqueous solution of the sulfate, evaporating the mixture to dryness, and heat-treating the resultant mixed powder. An exhaust gas purifying apparatus includes an exhaust gas purifying filter having a high exhaust gas purification rate and an excellent durability. The filter includes a ceramic filter with a heat-resistant coating layer thereon for support of the catalyst.

Abstract: The present invention relates to a shaped solid acid catalyst for the isomerization of hydrocarbons and so on, which has a high activity and is excellent in strength and easily handleable, and processes for the preparation thereof. This catalyst comprises a support comprising zirconia having a tetragonal form and alumina, and a sulfureous component and, if necessary, a Group 8, 9 or 10 metal component, both being supported on the support, and has a specific surface area of 150 m.sup.2 /g or above. The catalyst can be prepared by kneading aluminum hydroxide, zirconium hydroxide and a sulfureous compound, shaping the kneaded mixture, calcining the shaped material at such a temperature as to form tetragonal zirconia and, if necessary, supporting a Group 8, 9 or 10 metal component on the calcinedmaterial and calcining the resulting molding at 300 to 700.degree. C.

Abstract: A process for presulfurizing a hydrocarbon treatment catalyst and/or for preconditioning a catalyst, comprising one or two stages of incorporating sulfur into the pores of a hydrocarbon conversion catalyst conducted off-site in at least one zone that contains a catalyst, preferably in motion, and with either suilirated hydrogen (H.sub.2 S), sulfur, or a sulfur compound capable of evolving nascent suilirated hydrogen.

Abstract: Self-heating characteristics of a spontaneously combustible catalyst are reduced by treating spontaneously combustible catalysts with oxygen-containing hydrocarbons having at least 12 carbon atoms. The treatment is particularly suitable for reducing the self-heating characteristics of sulfidable metal oxide(s)-containing catalysts, presulfurized catalysts, presulfided catalysts or reduced catalysts. When applied to sulfur-containing catalysts, the treatment gives a catalyst that has suppressed self-heating properties without substantially compromising sulfur retention or activity. Further, a method of safely unloading a catalyst from a reactor is provided where the catalyst in the reactor is treated with a liquid mixture containing oxygen-containing hydrocarbon having at least 12 carbon atoms to wet the catalyst.

Abstract: Chiral diphosphines are constituted by an aromatic pentatomic biheterocyclic system, suitable to act as chiral ligands and complexes between the diphosphines and transition metals. They may be utilized as chiral catalysts in stereocontrolled reactions, such as diastereo- and enantioselective reduction reactions. Process is for the preparation of these chiral diphosphines; and process is for the preparation of these complexes and for their utilization as chiral catalysts in stereocontrolled reactions.

Abstract: A photocatalyst, represented by Formula IIPt(a)/Zn[M(b)]S IIwherein character "a" represents a percentage by weight of Pt in the photocatalyst, ranging from 0.1 to 3.5; character "M" is an element selected from the group consisting of Co, Fe, Ni and P; character "b" represents a mole % of M/Zn, ranging from 0.05 to 30. It can be active in the range of the visible light, live a semi-permanent life and produce hydrogen at a high yield without using any oxygen-containing organic compound as a hydrogen-producing promotor.

Abstract: Unsaturated cyclic ethers of the formula I ##STR1## whereZ is --(CHR.sup.4).sub.q -- or --(CHR.sup.4).sub.q --O--,q is 0, 1, 2 or 3 andR.sup.1,R.sup.2,R.sup.3,R.sup.4 are hydrogen or C.sub.1 -C.sub.4 -alkylare prepared by reacting diols of the formula II ##STR2## where Z, R.sup.1, R.sup.2 and R.sup.3 are as defined above, in the liquid phase at from 150 to 300.degree. C. in the presence of a cobalt-containing supported catalyst which has not been activated by reduction before use and comprises cobalt and a noble metal selected from the group consisting of platinum, palladium, rhodium, iridium, ruthenium, osmium, rhenium or a mixture thereof applied by sol impregnation on an inert support, wherein the supported catalyst is doped with sulfur. Sulfur-doped supported catalysts comprising cobalt and noble metals are also provided.

Abstract: A superacid catalyst comprising zirconium oxide having a purely tetragonal crystalline phase structure and whose surface has sulfate groups thereon in a quantity corresponding to the total coverage of the surface of the zirconium oxide by a monolayer of said sulfate groups, the zirconium oxide having a porosimetric distribution consisting of at least 70% of pores having a diameter ranging from 1-4 nm.

Abstract: A process comprises providing a catalyst comprising a support, a microwave absorption material, and a catalytically active phase; heating the catalyst with a source of microwave energy which is absorbed by said microwave absorption material to increase the temperature of the catalyst to a desired temperature; and contacting said heated catalyst with a hydrocarbon feedstock for upgrading same.

Abstract: Self-heating characteristics of a spontaneously combustible catalyst are reduced by treating spontaneously combustible catalysts with oxygen-containing hydrocarbons having at least 12 carbon atoms. The treatment is particularly suitable for reducing the self-heating characteristics of sulfidable metal oxide(s)-containing catalysts, presulfurized catalysts, presulfided catalysts or reduced catalysts. When applied to sulfur-containing catalysts, the treatment gives a catalyst that has suppressed self-heating properties without substantially compromising sulfur retention or activity. Further, a method of safely unloading a catalyst from a reactor is provided where the catalyst in the reactor is treated with a liquid mixture containing oxygen-containing hydrocarbon having at least 12 carbon atoms to wet the catalyst.

Abstract: A process for the production of a catalyst for preparing vinyl acetate in the gas phase from ethylene, acetic acid and oxygen or oxygen-containing gases which catalyst comprises palladium and/or its compounds, gold and/or its compounds and also alkali metal compounds on a particulate, porous support obtained bya) impregnating the support with soluble palladium and gold compounds,b) converting the soluble palladium and gold compounds into insoluble palladium and gold compounds by addition of an alkaline solution to the support,c) reducing the insoluble palladium and gold compounds on the support with a reducing agent in the liquid or gaseous phase,d) impregnating the support with at least one soluble alkali metal compound ande) finally drying the support at a maximum of 150.degree. C.,wherein the catalyst is brought into contact with at least one peroxidic compound in step b).

Abstract: The invention relates to the use of intramolecularly stabilized organometallic compounds as components in coordination catalyst systems, corresponding coordination catalyst systems and processes for the preparation of polymers by coordination polymerization of unsaturated hydrocarbons by catalysed metathesis of alkenes and alkynes using such coordination catalyst systems.

Abstract: A catalyst for the dehydrogenation of C6.sub.6 -C.sub.15 paraffins is disclosed. The catalyst contains, on a support, at least one platinum group component, at least one promoter component from the group tin, germanium and lead, and at least one additional modifier. The additional modifier contains at least one alkaline earth metal. The stability of the catalyst is essentially higher than that achieved by conventional use of an alkali metal.

Abstract: A process for the preparation of a hydrogenation catalyst by reduction of platinum in an oxidation stage of not less than 2 in an aqueous medium in the presence of a carboniferous support, optionally following partial poisoning with a sulfur, arsenic, tellurium, or antimony-containing compound, using a reducing agent, in which the reducing agent used is an ammonium or phosphonium salt of the general formula I?XR.sup.4 !.sub.n Y Iin which X stands for N or P, R stands for hydrogen, C.sub.1 --C.sub.18 alkyl, C.sub.5 --C.sub.10 cycloalkyl, phenyl radical, and also a C.sub.1 --C.sub.4 alkyl radical substituted by phenyl, the phenyl radicals being mono-to tri-substituted by C.sub.1 --C.sub.6 alkyl, halogen, nitro or amino, if desired, provided that the radicals R may be the same or different but cannot simultaneously denote hydrogen, if X is P, n is an integer of 1 to 3, and Y is an organic anion which can reduce platinum in an oxidation stage other than zero to platinum in the oxidation stage of zero.

Abstract: Methods for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physisorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics.

Abstract: The invention relates to an improved method of presulfurizing a sulfidable metal oxide(s)-containing catalyst which minimizes sulfur stripping upon start-up of a reactor and improves catalyst activity. The method consists of contacting a sulfidable metal oxide(s)-containing catalyst with elemental sulfur at a temperature such that said elemental sulfur is substantially incorporated in the pores of said catalyst by sublimation and/or melting and heating the sulfur-incorporated catalyst in the presence of a liquid olefinic hydrocarbon at a temperature greater than about 150.degree. C.

Abstract: A sulfated solid catalyst is provided which comprises (1) oxide or hydroxide of Group III or Group IV element, e.g. zirconium, and (2) a first metal comprising a metal or combination of metals selected from the group consisting of platinum, palladium, nickel, platinum and rhenium, and platinum and tin. The catalyst may further comprise (3) a second metal selected from the group consisting of Group VIII elements, e.g. iron. One embodiment of the invention further comprises (4) a third metal selected from the group consisting of Group V, VI and VII elements, e.g. manganese. The catalyst of the invention is useful for the isomerization of normal alkanes having 4 to 40 carbon atoms per molecule, for the naphtha upgrading of a hydrocarbon feedstock and for the hydrocracking of a hydrocarbon feedstock.

Abstract: A difunctional catalyst is disclosed which is constituted by:(a) silica particles partially coated with zirconia, acidified by means of the introduction of sulfate moieties,(b) one or more metal(s) from Group VIIIA.The preparation of said catalyst and its use in wax hydroisomerization are disclosed as well.

Abstract: A catalyst is disclosed comprising a thin outer shell of catalytic material bonded to an inner core of catalytically inert material. The catalyst is made by coating a catalytically inert core such as alpha alumina, with a thin layer of finely divided catalytically active material in a slurry of colloidal boehmite/pseudo boehmite then calcining to convert the boehmite/pseudo boehmite into .gamma. alumina thereby bonding it to the inert core. Catalysts made by this technique containing an outer shell of platinum on fluorided alumina in an inert core of alpha alumina .gamma. are attractive isomerization catalysts.

Abstract: For the impregnation into the pores of a hydrocarbon treatment catalyst of a sulfurizing agent chosen from element sulfur and organic polysulfides with the aid of a solvent, the impregnation process totally or partially comprises a constituent of the olefin or olefin fraction type, e.g., of the vegetable oil type, or a similar constituent. The use of such a constituent makes it possible to significantly reduce the exothermal effect which occurs during presulfurization, compared with the exothermal effects obtained without using such a constituent.

Abstract: The invention relates to an unproved method of presulfurizing a sulfidable metal oxide(s)-containing catalyst which minimizes sulfur stripping upon start-up of a reactor and improves catalyst activity. The method consists of contacting a sulfidable metal oxide(s)-containing catalyst with elemental sulfur at a temperature such that said elemental sulfur is substantially incorporated in the pores of said catalyst by sublimation and/or melting and heating the sulfur-incorporated catalyst in the presence of a liquid olefinic hydrocarbon at a temperature greater than about 150.degree. C.

Abstract: This invention relates to a hydrorefining catalyst containing ruthenium sulphide and cobalt and/or nickel sulphide on a refractory oxides support. These catalysts are only very slightly inhibited by polyaromatic compounds or hydrogen sulphide.

Abstract: Tin modified platinum-iridium catalysts provide high yields of C.sub.5 +liquid reformate in catalytic reforming, concurrent with high activity. In particular, the tin modified platinum-iridium catalysts are of unusually high selectivity, as contrasted with known iridium promoted platinum catalysts. The high selectivity is manifested in reforming a naphtha feed in a reactor charged to capacity with the catalyst, but particularly when used in the dehydrocyclization zone, or tail reactor of a series of reactors, while the lead reactors of the series contain a non tin-containing platinum catalyst, especially a platinum-iridium, or a platinum-rhenium catalyst. The tin modified platinum-iridium catalysts are also highly active, with only moderate loss in the high activity for which iridium stabilized platinum catalysts are known.

Abstract: A supported catalyst and a method of making a supported catalyst useful in the dehydrogenation of light paraffins. This catalyst comprises 0.3 to 5 wt. % Ga and 0.1 to 5 wt. % Pt on a spinel type support material characterized by the formula Mg.sub.x Al.sub.2 O.sub.3+x where x is a number from about 0.1 to 1.1. The improvement comprises the incorporation of a water soluble Mg salt into said support prior to the impregnation of Pt and Ga.

Abstract: The invention relates to an improved method of presulfurizing a sulfidable metal oxide(s)-containing catalyst which minimizes sulfur stripping upon start-up of a reactor and improves catalyst activity. The method consists of contacting a sulfidable metal oxide(s)-containing catalyst with elemental sulfur at a temperature such that said elemental sulfur is substantially incorporated in the pores of said catalyst by sublimation and/or melting and heating the sulfur-incorporated catalyst in the presence of a liquid olefinic hydrocarbon at a temperature greater than about 150.degree. C.

Abstract: A catalyst is disclosed comprising a thin outer shell of catalytic material bonded to an inner core of catalytically inert material. The catalyst is made by coating a catalytically inert core such as alpha alumina, with a thin layer of finely divided catalytically active material in a slurry of colloidal boehmite/pseudo boehmite then calcining to convert the boehmite/pseudo boehmite into .gamma. alumina thereby bonding it to the inert core. Catalysts made by this technique containing an outer shell of platinum on fluorided alumina in an inert core of alpha alumina .gamma. are attractive isomerization catalysts.

Abstract: The invention relates to a process making it possible when a refining catalyst is subject preferably in situ to the conventional activation reaction in the presence of hydrogen (generally at above 100.degree. C.) to carry out, as a result of the in situ presence of hydrogen, the sulphurization at the required stoichiometric or non-stoichiometric level of the active metal or metals in the composition of the catalyst. In the absence of hydrogen, the process consists of incorporating into the porosity of the new or regenerated catalyst at least one sulphurizing agent of general formula:R--S(n)--R'in which n is an integer from 3 to 20 and R represents an organic radical.The invention is characterized in that a critical elementary sulphur quantity is added to the sulphurizing agent.

Abstract: Ex situ presulfidation of hydrotreating catalysts comprising impregnating the catalysts with an aqueous solution of an organic sulfur compound, e.g. the diammonium salt of 2,5-dimercapto-1,3,4-thiadiazole and 2,2'-dithiodiethanol, followed by drying of the impregnated material. The dried material is activated by contacting it with hydrogen gas at elevated temperature.

Abstract: Tin modified platinum-iridium catalysts provide high yields of C.sub.5 + liquid reformate in catalytic reforming, concurrent with high activity. In particular, the tin modified platinum-iridium catalysts are of unusually high selectivity, as contrasted with known iridium promoted platinum catalysts. The high selectivity is manifested in reforming a naphtha feed in a reactor charged to capacity with the catalyst, but particularly when used in the dehydrocyclization zone, or tail reactor of a series of reactors, while the lead reactors of the series contain a non tin-containing platinum catalyst, especially a platinum-iridium, or a platinum-rhenium catalyst. The tin modified platinum-iridium catalysts are also highly active, with only moderate loss in the high activity for which iridium stabilized platinum catalysts are known.

Abstract: Disclosed is a catalyst composition for reforming a naphtha feed, which composition is composed of the metals, platinum, rhenium, and iridium on a refractory porous inorganic oxide support material, wherein the concentration of each of the metals platinum and rhenium is at least 0.1 percent and iridium at least 0.15 percent, and at least one of the metals is present in a concentration of at least 0.3 percent, and the sum-total concentration of the metals is greater than 0.9 percent.

Abstract: A process for producing hydroxylammonium salts of hydrogenating nitrogen monoxide in an acidic medium in the presence of a catalyst which is prepared by subjecting a platinum compound to a first reductive treatment with a thiosulfate or a thiosulfate combined with an alkali metal sulfide in the presence of a catalyst carrier, and a second reductive treatment with a reductant selected from the group consisting of formic acid, hydrogen, hydrazine and sodium borohydride at a temperature of 50.degree. C. to 150.degree. C.