Abstract: Presulfurization of a catalyst used, e.g., for hydrocarbon conversion, wherein a polysulfide is employed as the sulfurization agent. In the first stage of the presulfurization, phosphorous, a halogen, or compounds thereof are introduced.

Abstract: The instant invention relates to a method for converting phosphorus containing polymers from a two dimensional layered structure into a three dimensional structure by crosslinking such layers. The method and the resulting crosslinked polymers may be used to encapsulate active materials such as catalysts, pesticides, etc. by intercalating such active materials between the layers prior to crosslinking. Thus, the egress of said active materials into the environment during use may be hindered or prevented.

Abstract: A process for preparing a metal oxide catalyst for a fluidized bed process, which comprises adjusting the pH of an aqueous slurry containing an iron compound, an antimony compound, a phosphorus compound, and a silica carrier material as essential elements, with the atomic ratio of phosphorus to antimony being at least 0.1:1, to a pH of 3 or less, spray drying the slurry, and calcining the resulting particles; which catalyst exhibits excellent activity and physical properties suitable for use in a fluidized bed process and can be obtained with good reproducibility.

Abstract: A catalyst for the hydrotreatment of a hydrocarbon oil comprises a carrier of an inorganic oxide and an active component supported on the carrier and formed of at least one member selected from the group consisting of water-soluble compounds of molybdenum, tungsten, and the metal of Group 8 in the Periodic Table of Elements and at least one mercapto (--SH) group-containing organic compound selected from the group consisting a mercaptocarboxylic acids represented by the general formula:HS--(CH.sub.2).sub.n --COOR(wherein n stands for an integer in the range of 1 to 3 and R for a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or a linear or branched naphthenic alkyl group having 1 to 10 carbon atoms), amino-substituted mercaptans represented by the general formula:H.sub.

Abstract: The instant invention relates to a method for converting phosphorus containing polymers from a two dimensional, layered structure into a three dimensional structure by crosslinking such layers. The method and the resulting crosslinked polymers may be used to encapsulate active materials such as catalysts, pesticides, etc. by intercalating such active materials between the layers prior to crosslinking. Thus, the egress of said active materials into the environment during use may be hindered or prevented. The crosslinked polymers, themselves, may also be used as catalysts or as selective sorbents.

Abstract: A catalyst suitable for use as a three-way catalyst having low H.sub.2 S emissions for emission control and with substantially no ceria present is made with a refractory oxide particle or powder support having deposited thereon about 0.5-20% by weight of a non-rate earth oxide stabilizer, at least 0.5 to about 5% by weight of an alkali metal oxide as a promoter, and a catalytically-effective amount of one or more platinum group metals. The preferred refractory oxide is alumina and the non-rare earth oxide stabilizer can be an oxide such as ZrO.sub.2, MgO, CaO, SnO, CaO, Y.sub.2 O.sub.3, TiO.sub.2, ZnO, B.sub.2 O.sub.3, P.sub.2 O.sub.5, SnO.sub.2, Bi.sub.2 O.sub.3, or SiO.sub.2 with the preferred oxide being zirconia.

Abstract: Catalytic materials are modified by adding one or more electropositive and/or electronegative elements thereto in amounts sufficient to adjust the resultant geometric mean electronegativity to a value within a desired or predetermined range. The invention is particularly suited to the preparation of hydrocarbon hydroprocessing catalysts, particularly with respect to hydrodesulfurization catalysts comprising a support material containing a porous refractory oxide. With such catalysts, not only is the geometric mean electronegativity adjusted to a desired value, but if the electropositive or electronegative element added to the catalyst has pore growth promotion properties, the average pore size of the resultant catalyst is increased while its surface area, and usually also its total pore volume, is decreased.

Abstract: This invention relates to a process for disproportionation of hydrocarbon olefins by contacting said hydrocarbon at disproportionation conditions with a catalyst prepared by incorporating a metals solution containing cobalt, an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a phosphorus-containing compound, into an alumina hydrogel.

Abstract: This invention relates to a process for disproportionation of hydrocarbon olefins by contacting said hydrocarbon at disproportionation conditions with a catalyst prepared by incorporating a metals solution containing cobalt and an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a phosphorus-containing compound into an alumina hydrogel. The final calcined catalysts have surface areas greater than about 225 m.sup.2 /g and more than about 50% of their pore volume in pores having diameters less than about 70 .ANG..

Abstract: A catalyst for use in a process for oxidatively coupling methane to C.sub.2 and other hydrocarbons, including aromatic hydrocarbons, which is an iron-phosphorus-oxide catalyst having an iron to phosphorus ratio of from 0.1:1.0 to 2.0:1.0 is used.

Abstract: Method for preparing a biologically active 2-substituted succinic acid derivative involving asymmetrically catalytically hydrogenating the corresponding 2(E)-alkylidene succinate derivative in the presence of a rhodium complexed (R,R)-bisphosphine compound.

Abstract: A method for producing a lactone by hydrogenating a dicarboxylic acid, a dicarboxylic acid anhydride and/or a dicarboxylic acid ester in the presence of a catalyst, wherein the hydrogenation reaction is conducted in the liquid phase in the presence of (1) ruthenium, (2) an organic phosphine and (3) a compound of a metal selected from the group consisting of Groups IVA, VA and IIIB in the Periodic Table.According to the present invention, for the production of a lactone by hydrogenating a dicarboxylic acid, a dicarboxylic acid anhydride and/or a dicarboxylic ester, the reaction is conducted in a homogeneous liquid phase reaction by using the ruthenium, organic phosphine and compound of a metal selected from the group consisting of Groups IVA, VA and IIIB, of the present invention as the catalyst, whereby the desired lactone product can be obtained at high selectivity under a mild condition as compared with the conventional methods.

Abstract: A catalyst composition for decomposition of methanol comprising a substantially aluminum-free precipitate composed of a copper compound and a nickel compound, a phosphate salt of aluminum and an alkali metal compound, the content of the alkali metal being 1 to 100 atoms per 100 atoms in total of copper and nickel in the precipitate.

Abstract: Hydrocracking processes are disclosed using catalysts comprising silicoaluminophosphates of U.S. Pat. No. 4,440,871 characterized in the calcined form by an adsorption oxygen of at least 4 isobutane of at least 2 percent by weight at a partial pressure of 500 torr and a temperature of 20.degree. C.

Abstract: A process for the manufacture of catalysts for the reduction of nitrogen oxides in exhaust gases or for chemical air cleaning processes, in which catalyst moldings are produced from a mixture of solid primary materials which include iron oxide or mixtures of iron oxide and chromium oxide and/or manganese oxide, which are reduced to grain sizes less than 2 mm, with the use of inorganic binders and sulfuric acid, and with the possible addition of activating additives, wherein:(a) either the mixture of the solid primary materials is reacted with sulfuric acid, a mixture of sulfuric acid and phosphoric acid or mixtures of sulfuric acid and phosphoric acid containing sulfate, hydrogen sulfate, phosphate or hydrogen phosphate of ammonium, aluminum, iron, vanadium, manganese, molybdenum, chromium, copper and/or cobalt, and moldings are formed from this mixture, or the mixture of the solid primary materials is formed into moldings after the addition of fluid and/or phosphoric acid and/or phosphates, and these molding

Abstract: This invention relates to a process for the manufacture of catalysts for the reduction of nitrogen oxides in exhaust gases or for chemical air cleaning processes, in which catalyst moldings are produced from iron oxide or mixtures of iron oxide and chromium oxide and/or manganese oxide, which are reduced to grain sizes less than 2 mm, with the use of inorganic binders and sulfuric acid, and with the possible addition of activating additives.

Abstract: A method for producing a lactone by hydrogenating a dicarboxylic acid, a dicarboxylic acid anhydride and/or a dicarboxylic acid ester in the presence of a catalyst, wherein said catalyst is a ruthenium catalyst comprising (1) ruthenium, (2) an organic phosphine and (3) a conjugate base of an acid having a pKa of less than 2.

Abstract: A catalyst useful for hydroprocessing a hydrocarbon-containing oil contains at least one hydrogenation component on an amorphous, porous refractory oxide. The catalyst is prepared by impregnating support particles having a narrow pore size distribution and a mode pore diameter from about 70 to 80 angstroms with a solution containing a precursor of the hydrogenation components, followed by drying and calcining. The catalyst is useful for promoting a number of hydrocarbon hydroprocessing reactions, particularly hydrogenative desulfurization, dedemetallization and denitrogenation, and most particularyl, hydrodesulfurization of residuum-containing oils.

Abstract: Dewaxing processes for hydrocarbon feedstocks are disclosed using novel catalysts comprising non-zeolitic molecular sieves, such as the silicoaluminophosphates of U.S. Pat. No. 4,440,871. The products of the instant dewaxing processes are characterized by lower pour points than the hydrocarbon feedstock.

Abstract: This invention relates to a new catalyst composition. The catalyst composition comprises a catalytic component and a support comprising an amorphous combination of lanthana, alumina and aluminum phosphate, and may be characterized after calcination by a pore size distribution including about 5 to 20 vol. % within the pore size diameter range of 50 to 100 Angstroms, about 10 to 35 vol. % within the pore size diameter range of 100 to 150 Angstroms, about 15 to 50 vol. % within the pore size diameter range of 150 to 200 Angstroms and about 10 to 50 vol. % within the pore size diameter range of 200 to 400 Angstroms.

Abstract: Hydrocracking processes are disclosed using catalysts comprising silicoaluminophosphates of U.S. Pat. No. 4,440,871 characterized in the calcined form by an adsorption of oxygen of at least 4 percent by weight at a partial pressure of 100 torr and a temperature of -186.degree. C.

Abstract: The additional of redox-active metal components and ligands, alternatively or simultaneously, results in increased conversion and selectivity in the palladium-catalyzed oxidation of olefins to carbonyl products in the presence of polyoxoanions. In preferred modes, heteropolyoxoanions and Isopolyoxoanions containing tungsten, molybdenum and vanadium, individually or in combination, are described. The use of copper as the redox-active metal component shows reduced allylic reactivity. The elimination of chloride from the catalyst system provides substantial engineering advantages over the prior art, particularly, the reduction of corrosion and chloro-organic by-product formation. The use of redox-active metal components and/or ligands makes the palladium-polyoxoanion catalyst system industrially practicable.

Abstract: The instant invention relates to a method for converting phosphorus containing polymers from a two dimensional, layered structure into a three dimensional structure by crosslinking such layers. The method and the resulting crosslinked polymers may be used to encapsulate active materials such as catalysts, pesticides, etc. by intercalating such active materials between the layers prior to crosslinking. Thus, the egress of said active materials into the environment during use may be hindered or prevented. The crosslinked polymers, themselves, may also be used as catalysts or as selective sorbents.

Abstract: A process for the preparation of oxo-alkanedioic acids or diesters thereof by reacting an alkenoic acid or an ester thereof, at least one of the C atoms of the carbon carbon double bond carrying a H atom, with CO and H.sub.2 in the presence of a catalytic system prepared by combining:a. Pd and/or a Pd compound,b. a compound containing an anion of an acid having a pKa of less than 2, except hydrohalogenic acid and carboxylic acids, andc. a bidentate ligandR.sup.1 R.sup.2 --M--R--M--R.sup.3 R.sup.4wherein M is P, As or Sb, R is a divalent organic bridging group having at least two C atoms in the bridge, and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are optionally substituted hydrocarbon groups.

Abstract: Amorphous, porous metallo phosphates wherein the metal is Al, Ti, Ba, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mg, Sc, Cu, Fe and La or mixtures thereof, having average pore diameter from about 5 Angstroms to about 50 Angstroms that are useful as catalysts and catalyst supports.

Abstract: Supported catalysts for hydrotreating hydrocarbons comprise (a) at least one member selected from the group consisting of oxides of metals in Groups IV and VIII of the Periodic Table, and (b) at least one organic compound having a mercapto radical or radicals (--SH) selected from the group consisting of mercapto-carboxylic acids, including alkali metal, alkaline earth metal and ammonium salts thereof and esters thereof, bivalent mercaptans, amino-substituted mercaptans, and thiocarboxylic acids. These catalysts can be easily activated by treatment in the presence of hydrogen gas at a temperature in the range from room temperature to 400.degree. C. show higher activity than catalysts activated by conventional methods.

Abstract: A carbon monoxide oxidizing catalyst for removing carbon monoxide from an air comprises a porous carrier, and on said carrier, a palladium salt and a copper salt as main active components and a vanadium compound or a vanadium compound and a phosphorous compound as a promotor.

Abstract: A process for producing a cyclic amine represented by the general formula ##STR1## wherein each of R and R' is selected from hydrogen, a methyl group and an ethyl group, and n is an integer of 2 to 5, which comprises vapor-phase intramolecular dehydration reaction of an alkanolamine represented by the general formula ##STR2## wherein R, R' and n are as defined above, said reaction being carried out in the presence of, as a catalyst, an oxide composition represented by the following formulaX.sub.a P.sub.b Y.sub.c O.sub.dwherein X is at least one element selected from transition metal elements of Groups I through VIII, lanthanide elements, actinide elements and elements of Group IIIA in the periodic table, Si, Ge, Sn, Pb, Sb and Bi, P is phosphorus, Y is at least one element selected from alkali metal elements and alkaline earth metal elements, O is oxygen, the suffixes a, b, c and d are the atomic ratios of the elements X, P, Y and O respectively, and when a=1, b=0.01-6, preferably 0.

Abstract: A paraffin or mixture of paraffins having from 2 to 5 carbon atoms is oxidatively dehydrogenated in the presence of a cobalt based catalyst composition which has been calcined in the absence of oxygen. The catalyst composition comprises cobalt; phosphorus; at least one promoter selected from the group consisting of zinc, titanium, zirconium, niobium, indium, lead and bismuth; at least one alkali metal and oxygen. The catalyst composition may also contain sulfur and/or a halogen. If the feed to the oxidative dehydrogenation process contains paraffins having more than two carbon atoms, some cracking of such paraffins will also occur at the conditions at which the oxidative dehydrogenation process is carried out.

Abstract: Catalytic materials are modified by adding one or more electropositive and/or electronegative elements thereto in amounts sufficient to adjust the resultant geometric mean electronegativity to a value within a desired or predetermined range. The invention is particularly suited to the preparation of hydrocarbon hydroprocessing catalysts, particularly with respect to hydrodesulfurization catalysts comprising a support material containing a porous refractory oxide. With such catalysts, not only is the geometric mean electronegativity adjusted to a desired value, but if the electropositive or electronegative element added to the catalyst has pore growth promotion properties, the average pore size of the resultant catalyst is increased while its surface area, and usually also its total pore volume, is decreased.

Abstract: A process for producing a high octane gasoline from a hydrocarbon feedstock in which the feedstock is contacted in the presence of hydrogen under hydrocracking conditions, preferably ammonia-rich hydrocracking conditions, with a hydrocracking catalyst comprising at least one hydrogenation metal component in combination with a cracking component. The preferred cracking components are Y zeolites and the catalyst preferably contains a nickel hydrogenation metal component, particularly in an amount greater than 13 weight percent, calculated as NiO. The catalyst may also contain a Group VIB metal component, such as a molybdenum component, particularly in a mole ratio greater than about 2 to 1, calculated as NiO to Group VIB metal trioxide. It has been found that such a process produces gasoline fractions having substantially increased research and motor octane numbers.

Abstract: A method is disclosed which provides improved control over the noble-metal exchange of zeolite catalyst by using bulky organic bases to control pH during the metal loading step.

Abstract: This invention relates to a process for preparing highly active hydrotreating catalysts prepared by incorporating an element selected from the group consisting of nickel, cobalt and mixtures thereof, a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof, into a phosphated alumina hydrogel. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g, at least about 20% of the pore volume in pores having diameters greater than about 350 .ANG. and at least about 20% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: This invention relates to a process for preparing highly active hydrotreating catalysts prepared by incorporating an element selected from the group consisting of nickel, cobalt and mixtures thereof, a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a stabilizing amount of phosphorus into an alumina hydrogel. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g, at least about 20% of the pore volume in pores having diameters greater than about 350 .ANG. and at least about 20% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: This invention relates to a process for preparing highly active hydrotreating catalysts prepared by incoporating an element selected from the group consisting of nickel, cobalt and mixtures thereof, a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a stabilizing amount of phosphorus into an alumina hydrogel. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g, at least about 20% of the pore volume in pores having diameters greater than about 350 .ANG. and at least about 20% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: The invention relates to a vanadium/phosphorus mixed oxide catalyst, a process for its preparation and its use for the preparation of maleic anhydride.The catalyst according to the invention is prepared by reacting a vanadium(V) compound with phosphoric acid and/or a compound forming phosphoric acid with heating, optionally in the presence of water, and subsequently treating the product obtained after the reaction with organic solvents and/or diluents having reducing activity, optionally in the presence of a promoter, at an elevated temperature.

Abstract: The invention relates to a catalyst in the form of a plate for nitrogen oxide reduction in exhaust gases manufactured by molding granular Cr.sub.2 O.sub.3 or a mixture of granular Fe.sub.2 O.sub.3 with Cr.sub.2 O.sub.3 with phosphoric acid or sulphuric acid as binder, characterized by the fact that a combination is molded of separately prepared mixtures of Cr.sub.2 O.sub.3 or (Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3) with phosphoric acid as binder, and of Cr.sub.2 O.sub.3 or (Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3) with sulphuric acid as binder.

Abstract: This invention relates to a new and useful amorphous, solid, combination refractory composition and to its synthesis. The new composition is an x-ray amorphous rare earth aluminum phosphorus oxide having high surface area and unique pore size distribution. The composition is useful as a catalyst support and provides improvement over prior art supports such as alumina or aluminum phosphate for certain catalytic applications.

Abstract: A process for the manufacture of catalyst moldings from granular catalyst material, preferably iron ore, chromium ore or a similar ore, with the use of a binder is disclosed. The granular catalyst material is thermally pre-treated in a temperature range of approximately 250.degree. to 1000.degree. C., before it is mixed with dilute and/or concentrated sulfuric acid functioning as the binder.

Abstract: An exhaust gas cleaning catalyst composed of a refractory three-dimensional structure and a catalytically active substance supported thereon. That surface or part of the catalyst which makes contact with an exhaust gas is formed of numerous irregularly arranged protrusions composed of a refractory inorganic powder having a particle diameter of 5 to 300 micrometers or a mixture of it with refractory inorganic fibers and the catalytically active substance supported on the protrusions.

Abstract: In a process for the manufacture of catalyst moldings a natural raw material containing Fe.sub.2 O.sub.3, Cr.sub.2 O.sub.3 or another such catalyst component such as TiO.sub.2, NbO.sub.2, WO.sub.3, V.sub.2 O.sub.5 or MoO.sub.3 is screened to a grain size equal to or less than approximately 0.25 mm. This screened base mixture is thoroughly blended, and then preferably a concentrated sulphuric acid is added. This mixture of material is then pressed into a molding in a hydraulic press with a pressure of approximately 500 bar to produce the molding.

Abstract: This invention relates to a method of preparing a metal-containing amorphous magnesia-alumina-aluminum phosphate catalyst support involving the admixture of an organic cation having a size equal to or greater than 2 Angstroms, the organic cation preferably being a tertiary or a tetraalkylammonium or phosphonium cation, the method permits recovery of a catalyst support having a controlled pore size distribution. The invention also relates to an improved catalytic support as well as an improved petroleum residua upgrading process comprising hydrotreating residua in the presence of the improved catalyst support.

Abstract: A cobalt-molybdenum catalyst and a method for preparing same, said catalyst useful for the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) of distillates of petroleum. The catalyst is supported by aluminum phosphate or an aluminum borate. In a preferred embodiment the catalyst has a low cobalt content, between 0.5% and 2.0% by weight calculated as CoO, and a molybdenum content of between 10% and 20% by weight, calculated as MoO.sub.3. The phosphorus or boron compounds added to the aluminum before the impregnation of the active metals prevents the formation of undesirable compounds of the CoAl.sub.2 O.sub.4 type, which is inactive in HDS. It is for that reason that the catalyst has a formulation with 70% less cobalt than the previous state-of-the-art catalysts. Very small crystals, highly dispersed on the surface of the catalyst, whose formula is CoMoO.sub.4, are responsible for the stability and the high level of activity in HDS and HDN which results.

Abstract: A process is provided for the oxydehydrogenation of saturated carboxylic acids with oxygen in the presence of iron phosphorus oxide catalysts containing promoters selected from the group Ag, Al, B, Cd, Co, Cr, Cu, Ga, Ge, In, Mn, Ni, Te, Th, Ti, Tl, U, V, Zn, Zr, rare earths and mixtures thereof.

Abstract: The invention relates to catalyst plates for reducing nitrogen oxide in exhaust gases. These plates are molded of granular Fe.sub.2 O.sub.3 catalyst material and a binder. To achieve high activity and strength in the plates, these are molded of a combination of a first mixture comprised of Fe.sub.2 O.sub.3 catalyst material and phosphoric acid as binder, and a second, separately-produced mixture comprised of Fe.sub.2 O.sub.3 catalyst material and sulphuric acid as binder. The plates can also be a molding having layers, which layers have alternate layers of the first and second mixtures.

Abstract: A hydroprocessing catalyst contains nickel, phosphorus and about 19 to about 21.5 weight percent of molybdenum (MoO.sub.3) components on a porous refractory oxide. The catalyst has a narrow pore size distribution wherein at least 75 percent of the pore volume is in pores of diameter from about 50 to about 110 angstroms, at least 10 percent of the pore volume in pores of diameter less than 70 angstroms and at least 60 percent of the pore volume in pores of diameter within about 20 angstroms above or below the average pore diameter. The catalyst is employed to hydroprocess a hydrocarbon oil, especially those oils containing sulfur and nitrogen components.

Abstract: This invention relates to a process for preparing highly active hydrotreating catalysts prepared by incorporating nickel, an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a stabilizing amount of phosphorus into an alumina hydrogel support. The final calcined catalysts have surface areas greater than about 300 m.sup.2 /g, crush strengths greater than about 18 lbs and more than about 80% of their pore volume in pores having diameters less than about 70 .ANG..

Abstract: A process for the production of 1,12-dodecanoic diacid by hydroformylating an olefin in the presence of a rhodium catalyst and oxidation with oxygen of the aldehyde which is thus formed wherein 1,9-decadiene is hydroformylated in the presence of hydridotris-triphenylphosphine-rhodium-carbonyl combined with triphenylphospine and/or triphenylphosphite, and the 1,12-dodecanedialdehyde which was thus formed is oxidized with oxygen in the presence of inorganic or organic Co(II) salts.

Abstract: A process for the production of 1,12-dodecanoic diacid by hydroformylating an unsaturated carboxy compound in the presence of a rhodium catalyst and oxidation of the aldehyde with oxygen, wherein undecyl-10-ene-acid is hydroformylated in the presence of hydridotristriphenylphosphine-rhodium-carbonyl combined with triphenylphosphine and/or triphenylphosphite, and the 11-formyl undecanioc acid which is thus formed is oxidized with oxygen in the presence of inorganic and organic Co(II) salts.

Abstract: A process for the manufacture of novel phosphorus-vanadium and phosphorus-vanadium cometal catalysts having a characteristic X-ray diffraction pattern suitable for use in the manufacture of maleic anhydride from butane and other C.sub.4 hydrocarbon feedstocks which process comprises reacting at a temperature of about 0.degree. C. to about 200.degree. C. a vanadium compound in an organic ether solvent having about 2 to about 10 carbon atoms with a phosphoryl halide in the presence of water or an aliphatic alcohol having from about 1 to about 8 carbon atoms, eliminating the solvent, and activating the catalyst by the addition of the hydrocarbon feedstock and water and a phosphorus compound at a temperature of about 300.degree. C. to about 500.degree. C. wherein the amount of water added is about 1,000 parts per million to about 40,000 parts per million by weight of the reactor feed gas stream is disclosed. The catalysts are useful for the manufacture of maleic anhydride from butane and other C.sub.