Abstract: Disclosed is a method for producing a conjugated diene by subjecting a monoolefin having a carbon atom number of 4 or more and an oxygen gas to an oxidative dehydrogenation reaction by using a molybdenum-containing metal oxide catalyst under heat removal with a coolant, wherein an amount of molybdenum adhered onto a cooling heat transfer surface within a reactor is kept at not more than 20 mg/m2, or not only a surface roughness Ra of a cooling heat transfer surface within a reactor is not more than 3 ?m, but a temperature difference between a reaction temperature and a coolant temperature is in the range of from 5 to 220° C.

Abstract: In a process for producing anhydrides in a tubular reactor, gaseous reactants are passed downwardly through at least one reactor tube to a catalyst carrier where they pass into a passage defined by an inner perforated wall of a catalyst container before passing radially through the catalyst bed towards a perforated outer container wall. The reaction occurs as gas contacts the catalyst. Unreacted reactant and product exits the container though the perforated outer wall and then upwardly between an inner surface of a container skirt and the outer wall of the container and then over the end of the skirt and caused to flow downwardly between the outer surface of the skirt and the inner surface of the reactor tube where heat transfer takes place. These steps are repeated at any subsequent catalyst carrier product is then removed from the reactor outlet.

Abstract: A process for producing a ringlike oxidic shaped body by mechanically compacting a pulverulent aggregate introduced into the fill chamber of a die, wherein the outer face of the resulting compact corresponds to that of a frustocone.

Abstract: A chemical reactor including: a plurality of heat exchange plates which between them define reaction compartments, in which reactor each heat exchange plate includes two walls between them defining at least one heat exchange space, the respective walls being fixed together by joining regions, and the reactor also comprises at least one injection device for injecting substance into the reaction compartments, said substance-injection device passing through the heat-exchange plates in respective joining regions thereof. Also, a chemical reaction process that can be carried out in this reactor.

Abstract: In a process for producing anhydrides in a tubular reactor, gaseous reactants are passed downwardly through at least one reactor tube to a catalyst carrier where they pass into a passage defined by an inner perforated wall of a catalyst container before passing radially through the catalyst bed towards a perforated outer container wall. The reaction occurs as gas contacts the catalyst. Unreacted reactant and product exits the container though the perforated outer wall and then upwardly between an inner surface of a container skirt and the outer wall of the container and then over the end of the skirt and caused to flow downwardly between the outer surface of the skirt and the inner surface of the reactor tube where heat transfer takes place. These steps are repeated at any subsequent catalyst carrier product is then removed from the reactor outlet.

Abstract: A process for producing a ringlike oxidic shaped body by mechanically compacting a pulverulent aggregate introduced into the fill chamber of a die, wherein the outer face of the resulting compact corresponds to that of a frustocone.

Abstract: Processes for decreasing fumaric acid deposits in preparing maleic anhydride by heterogeneously catalyzed oxidation of a hydrocarbon with molecular oxygen. Maleic anhydride is absorbed from the crude mixture in an absorbent in an absorption column and desorbed in a desorption column, the entirety or portion of absorbent depleted in maleic anhydride, for controlled precipitation of fumaric acid, being cooled and/or concentrated by evaporating a portion of absorbent such that the difference between the concentration of fumaric acid in the recycle stream at the outlet of the desorption column under existing conditions and the equilibrium concentration of fumaric acid according to the solubility curve after cooling and/or evaporation of a portion of absorbent is ?250 ppm by weight, and the fumaric acid precipitated as a solid is removed completely or partly from the absorbent recycling system and the fumaric acid-depleted absorbent is recycled completely or partly to the absorption column.

Abstract: Improved apparatus for use in process systems which include exothermic chemical conversions of organic compounds to value added products is disclosed, more particularly, flow reactors for exothermic chemical conversions using a fixed heterogeneous catalyst with means for control of the exotherm.

Abstract: Two zone (11, 12; 21, 22; 31, 32; 41, 42) fluidized bed reactor (10, 20, 30, 40), wherein the upper zone (11, 21, 31, 41) presents a different section than the lower zone (12, 22, 32, 42). In one of the two zones (11, 12; 21, 22; 31, 32; 41, 42), a zone of reducing atmosphere is created and, in the other zone, a zone of oxidising atmosphere is created. In a preferred embodiment, the section of the upper zone (11, 21, 31, 41) is larger than that of the lower zone (12, 22, 32, 42), creating a reducing atmosphere in the upper zone (11, 21, 31, 41) and an oxidising atmosphere in the lower zone (12, 22, 32, 42). Rows of flow distributor tubes exist in the upper zone (11, 21, 31, 41) to avoid the appearance of dead zones.

Abstract: A process for recovering solid reaction products during partial oxidation of hydrocarbons in a liquid solvent as a reaction medium by multi-stage evaporative crystallization includes determining a final temperature of the multi-stage evaporative crystallization based on a melting point of the solvent. The pressure and temperature of the solvent is reduced in steps via successive crystallization stages until the final temperature is reached. Each of the crystallization stages includes a compressor configured to perform the reducing of the pressure and to withdraw vapors formed. The vapors from the compressor of a lower expansion pressure crystallization stage are introduced into a vapor discharge conduit of a next successive higher expansion pressure crystallization stage upstream of the compressor of the higher expansion pressure crystallization stage.

Abstract: Improved apparatus for use in process systems which include exothermic chemical conversions of organic compounds to value added products is disclosed, more particularly, flow reactors for exothermic chemical conversions using a fixed heterogeneous catalyst with means for control of the exotherm.

Abstract: A process for producing a ringlike oxidic shaped body by mechanically compacting a pulverulent aggregate introduced into the fill chamber of a die, wherein the outer face of the resulting compact corresponds to that of a frustocone.

Abstract: Improved apparatus for use in process systems which include exothermic chemical conversions of organic compounds to value added products is disclosed, more particularly, flow reactors for exothermic chemical conversions using a fixed heterogeneous catalyst with means for control of the exotherm.

Abstract: Methods comprising: providing an oxidation catalyst bed; and starting up the oxidation catalyst at a temperature of 360° C. to 400° C. with an amount of air of 1.0 to 3.5 standard m3/h and a hydrocarbon loading of 20 to 65 g/standard m3, such that a hot spot having a temperature of 390° C. to <450° C. is formed in the first 7-20% of the catalyst bed.

Abstract: A process for recharging the reaction tubes of a tube bundle reactor with a new fixed catalyst bed, in which a heterogeneously catalyzed partial gas phase oxidation of an organic compound had been performed beforehand in a preceding fixed catalyst bed comprising Mo-comprising multielement oxide active compositions to form a steam-comprising product gas mixture, in which, before the recharge, solid deposit which had been deposited on the tube inner walls and comprises molybdenum oxide and/or molybdenum oxide hydrate is brushed away with the aid of a brush.

Abstract: In a process for purifying an organic solvent for the absorption of maleic anhydride from a gaseous mixture, in which the maleic anhydride is separated off from the solvent, a substream is taken from the solvent stream, this substream is distilled and returned to the solvent circuit, the proposed improvement comprises separating off a low-boiling fraction and a high-boiling fraction from the fraction consisting essentially of purified solvent and feeding the fraction consisting essentially of purified solvent back into the solvent stream.

Abstract: This invention concerns catalysts comprising a molybdenum compound of formula I, II, III, IV or V VqMoAyOz??I NiMoxByOz???II VNiwMoxCy?Oz???III CoNiwMoxDyOz????IV VNiwCorMoxEyOz????V wherein: A is at least one cation selected from the group consisting of cations of: Cr, Sb, Co, Ce and Pb; B is at least one cation selected from the group consisting of cations of: Sb, Al and W; C is at least one cation selected from the group consisting of cations of: Fe, Zn, Al, Sb, Bi, W, Li, Ba, Nb and Sn; D is at least one cation selected from the group consisting of cations of: Ba, Mn, Al, Sb, Sn, and W; E is at least one cation selected from the group consisting of cations of: Fe, Ca, Mn, Sr, Eu, La, Zr, Ga, Sn and Pb; q, r, w, x and y are each independently a number from 0.1 to 10 and y? is a number from 0 to 10, z, z?, z?, z??, and z?? are determined using the amounts and oxidation states of all cations present in each formula.

Abstract: A process for the preparation of maleic anhydride by heterogeneously catalyzed gas-phase oxidation in a reactor with feed for the reaction mixture at one end of the reactor and discharge of the product mixture at the opposite end of the reactor, and with devices for dissipating the heat of reaction which are arranged in the reactor interior and through which a heat-exchange medium flows and which are designed as heat-exchanger plates.

Abstract: Disclosed is a process for the production of maleic anhydride, which comprises: reacting a hydrocarbon with an oxygen-containing gas in the presence of a catalyst; recovering maleic anhydride from the reaction gas; recovering unreacted hydrocarbon from the remaining gas; and returning the hydrocarbon thus recovered to the reactor for re-use, wherein said reaction is effected under the conditions such that the hydrocarbon concentration X (vol %) and oxygen concentration Y (vol) in all the gases to be fed into the reactor, the hydrocarbon conversion Z (t) in the reactor and the oxygen concentration W (vol %) in all the effluent gases from the reactor satisfy the following relationships: Y≧20, X+Y≦70, 1≦Y/X≦5, and 20(Y−10)/X≦Z≦25Y/X or 2≦W≦10.

Abstract: Disclosed herein are compositions comprising organic anhydrides having a reduced tendency to discolor with time, even when held at elevated temperatures for extended times. The compositions are produced by mixing at least one acid halide and various derivatives of hydroxy carboxylic acids with an anhydride to form a homogenous solution. Also disclosed is a process for preparing the compositions.

Abstract: Disclosed is a process for the preparation of maleic anhydride which comprises subjecting an aliphatic hydrocarbon having four or more carbon atoms to gas phase oxidation reaction in the presence of a catalyst, wherein supposing that the function of reaction product gas composition is FL and the function of temperature and pressure of reaction product gas is FR, the safety index F satisfies the following relationship (1): F=FL−FR>0  (1) According to the present invention, it is possible that the loss of unreacted hydrocarbon and maleic anhydride as reaction product due to non-catalytic oxidation reaction is prevented while effecting the reaction in a stable manner, whereby the yield of maleic anhydride can be kept maximum while assuring safety.

Abstract: This invention relates to catalysts useful in the vapor phase oxidation of hydrocarbons, such as 1,3-butadiene to furan and maleic anhydride. The catalysts comprise vanadium oxides, vanadium phosphorus oxides or vanadium antimony oxides incorporated in a matrix comprising oxides or oxyhydroxides of silicon, titanium, tantalum and/or niobium derived using sol-gel chemistry, optionally in the presence of an organic directing agent, such as dodecylamine.

Abstract: Disclosed is a process for the production of maleic anhydride, which comprises: reacting a hydrocarbon with an oxygen-containing gas in the presence of a catalyst; recovering maleic anhydride from the reaction gas; recovering unreacted hydrocarbon from the remaining gas; and returning the hydrocarbon thus recovered to the reactor for re-use, wherein said reaction is effected under the conditions such that the hydrocarbon concentration X (vol %) and oxygen concentration Y (vol %) in all the gases to be fed into the reactor, the hydrocarbon conversion Z (%) in the reactor and the oxygen concentration W (vol %) in all the effluent gases from the reactor satisfy the following relationships: Y≧20, X+Y≦70, 1≦Y/X≦5, and 20(Y−10)/X≦Z≦25Y/X or 2≦W≦10.

Abstract: N-butane and molecular oxygen are reacted in a first reactor to form maleic anhydride, the produced maleic anhydride is scrubbed to separate maleic anhydride values, n-butane is added to the scrubber gases and these are reacted in a second reactor to form additional maleic anhydride.

Abstract: A process for producing maleic anhydride is described, which comprises (i) reacting a hydrocarbon with oxygen in a vapor phase in the presence of a catalyst to yield a reaction mixture gas containing maleic anhydride, (ii) bringing the reaction mixture gas into contact with an organic solvent to collect the maleic anhydride in the organic solvent, (iii) separating at least part of the maleic anhydride from the organic solvent, (iv) washing with an aqueous alkali solution at least part of the organic solvent from which maleic anhydride has been separated, and (v) reusing the resultant washed organic solvent and the residual organic solvent for contact with the reaction mixture gas.

Abstract: Hydrocarbon conversion processes using a new family of crystalline manganese phosphate compositions is disclosed. These compositions have an extended network; which network can be a one-, two-, or three-dimensional network. The composition has an empirical formula of:(A.sup.a+).sub.v (Mn.sup.b+)(M.sup.c+).sub.x P.sub.y O.sub.zwhere A is a templating agent such as an alkali metal, M is a metal such as Al, Fe.sup.3+ and "b" is the average manganese oxidation state and varies from greater than 3.0 to about 4.0.

Abstract: Petrochemicals are produced by the vapor phase reaction of a hydrocarbon with air in the presence of a suitable catalyst. The petrochemical product is removed from the product gas stream, and part or all of the remaining gas stream is passed through a bed of hydrophobic adsorbent, which adsorbs mainly the unreacted hydrocarbon from the gas stream without adsorbing water vapor. The adsorbed hydrocarbon is purged from the bed with air, and the air-hydrocarbon mixture is recycled to the partial oxidation reactor.

Abstract: The present invention provides a process for recovering fumaric acid formed as a by-product during the production of maleic anhydride so that both fumaric acid and maleic anhydride are obtained. The process of the present invention further eliminates the wasting of MAN that occurs when fumaric acid is incinerated and improves the production of maleic anhydride by eliminating a source of fouling caused by the fumaric acid which leads to down-time in the reaction process to clean out the fumaric acid.

Abstract: A process for recovering phthalic anhydride and maleic anhydride from a maleic anhydride-rich vapor phase oxidation product comprising the step of: contacting the vapor phase oxidation product with: (i) at least one by-product stream having a freezing point which is lower than the freezing point of pure phthalic anhydride; and/or (ii) a solvent having a boiling point in the range between about 150.degree. to 350.degree. C. and a freezing point of less than 40.degree. C.; wherein a vapor-to-liquid weight ratio in the range between about 2 to 20 is exhibited within the contacting means, thereby forming a liquid phase phthalic anhydride product having a phthalic anhydride concentration in the range between about 50-100 wt. % and a first vapor stream.

Abstract: Petrochemicals are produced by the vapor phase reaction of a hydrocarbon with air in the presence of a suitable catalyst. The petrochemical product is removed from the product gas stream, and unreacted hydrocarbon in part or all of the remaining gas stream is recovered by subjecting the gas stream to a TSA process in which the adsorbed hydrocarbon is desorbed at elevated pressure by purging the adsorbent with hot compressed air, the air being heated by compression. The compressed air-desorbed hydrocarbon mixture is recycled to the reactor.

Abstract: A petrochemical is produced by the vapor phase reaction of a hydrocarbon with air in the presence of a suitable catalyst. The petrochemical is removed from the reactor effluent, and part or all of the remaining petrochemical-free gas stream is passed through a hydrocarbon-selective adsorbent, which adsorbs hydrocarbon from the gas stream, leaving a hydrocarbon-depleted waste gas. Hydrocarbon is purged from the adsorbent with air, and the air-hydrocarbon mixture is recycled to the partial oxidation reactor. The purge air, and preferably both the purge air and the petrochemical-free gas stream are dried by passage through beds of zeolite 3A prior to being introduced into the hydrocarbon-selective adsorbent, and the beds of zeolite 3A are regenerated by passing heated hydrocarbon-depleted waste gas therethrough.

Abstract: An improved process for the preparation and recovery of maleic anhydride in which the recovery of maleic anhydride from a gaseous reaction mixture includes absorbing the maleic anhydride in a solvent and subsequently stripping maleic anhydride from the solvent to obtain crude maleic anhydride product and regenerated absorbing solvent containing polymeric tars and other contaminants. In accordance with the improvement, at least a portion of the regenerated solvent is contacted in an agitated extraction zone with an aqueous liquid extractant to hydrolyze the polymeric tars, transfer water-soluble contaminants to the aqueous extract phase and produce a mixture comprising an aqueous extract phase containing water-soluble contaminants and an organic raffinate phase comprising regenerated absorbing solvent having a reduced concentration of polymeric tars. The aqueous extract and organic raffinate phases are then separated and the organic phase is recycled and used again to absorb maleic anhydride.

Abstract: Hydrocarbon derivatives are produced by contacting a hydrocarbon with oxygen obtained from an air separation unit in the presence of a partial oxidation reaction catalyst. After separation of the hydrocarbon derivative from the reactor effluent, unreacted hydrocarbon is recovered from the effluent by adsorbing the unreacted hydrocarbon onto an adsorbent at superatmospheric pressure and removing the adsorbed hydrocarbon from the adsorbent by depressurizing said adsorbent and purging the adsorbent with nitrogen obtained from the air separation unit. The recovered unreacted hydrocarbon is recycled to the partial oxidation reactor.

Abstract: The catalytic process for producing maleic anhydride employs a catalytic device formed of pairs of vertically extending vapor permeable walls which define flow channels between the pairs of walls. In addition, each pair of walls defines an interspace which contains a catalyst. A mixture of air and n-butane is passed through the flow channels while a heat exchange medium, such as a molten salt, is passed in heat exchange relation to the catalytic device while effecting an exothermic catalytic reaction of the mixture within the catalytic device. The resulting gaseous maleic anhydride is produced as a product.

Abstract: A method for the production of maleic anhydride in which a hydrocarbon of 4 to 6 carbon atoms is subjected to a vapor phase catalytic oxidation reaction in the presence of a metal oxide catalyst, characterized in that the metal oxide catalyst includes a metal oxide containing Mo, V, Te and X (X representing one or more elements selected from the group consisting of Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B, In, P and Ce) as constituent elements thereof, and the proportion of Mo to the total metal elements in the metal oxide is 0.25 or greater in terms of the atomic ratio, and the atomic ratio of each of the other constituent elements V, Te and X with respect to Mo is in the range of 0.01-1.0.According to the method, the object maleic anhydride may be produced at a high yield using a hydrocarbon of 4 to 6 carbon atoms, particularly n-butane, as the starting material.

Abstract: Process for improving a controlled oxidation reaction between at least one reactant and oxygen, in which at least one reactant is reacted with oxygen or an oxygen containing gas, constituting a reaction mixture, in the presence of at least one additional gas which is introduced into said reaction mixture and is selected from methane, ethane and helium, and the resulting reaction product from the oxidation reaction is possibly treated so as to give a final product.

Abstract: An improvement in the oxidation catalyst used for the partial oxidation of n-butane and containing vanadium and phosphorus, zinc and lithium mixed oxides which comprises adding a molybdenum compound modifier in an amount of from about 0.005 to 0.025/1 Mo/V to the catalyst during the digestion of the reduced vanadium compound by concentrated phosphoric acid. The addition of Mo produces a catalyst which is very stable more active system and longer lived than the unmodified catalyst.

Abstract: A process for reacting a fluid phase (gaseous and/or liquid phase) in contact with a solid phase in a reaction zone, wherein the improvement in said process comprises reacting the fluid phase in contact with the solid phase in a horizontally-oriented fluidized bed vessel. The vessel includes at least two compartments or stages, and includes means for vibrating the vessel. The process of the present invention enables one to effect fluidization of the solid phase independently of the flow rate or velocity of the fluid phase, thus enabling proper contact time of the fluid phase with the solid phase and minimizing the amount of fluid phase reactant to be recycled.

Abstract: The invention relates to a catalyst for producing phthalic anhydride by gas phase catalytic oxidation of o-xylene and/or naphthalene with molecular oxygen or gas containing molecular oxygen and, to a process for producing phthalic anhydride by using said catalyst. The catalyst is made by supporting, on a heat-resistant inorganic carrier, a catalytic active substance which comprises: vanadium oxide; anatase type titanium dioxide having specific surface area of 10 to 60 m.sup.2 /g; niobium; at least one element selected from potassium, cesium, rubidium and thallium; phosphorus; and antimony. The catalytic active substance is prepared by using a five-valent antimony compound as an antimony source. The process for producing phthalic anhydride comprises use of said catalyst.

Abstract: An improvement in a process for the manufacture of maleic anhydride by catalytic oxidation of n-butane in the presence of trimethyl phosphate over a fixed bed vanadium phosphorus oxide catalyst in a tubular reactor. The trimethyl phosphate content of the gas entering the reactor within a range of between about (0.9) N and about (1.1) N where N is a normative concentration of trimethyl phosphate in ppm as determined by the following relationship:N+5.times.C.sub.4 +6.times.(H.sub.2 O-2.4)+0.75.times.(CONV-c)+(SV/(25.times.P.sub.in))where:C.sub.4 .times.the mole % of n-butane in the gas entering the reactor;H.sub.2 O.times.the mole % moisture in the gas entering the reactor;CONV.times.% butane conversion in the reactor;SV.times.gas hourly space velocity of the gas at the inlet of the reactor, reduced to one atmosphere pressure and 60.degree. F.;P.sub.in .times.the pressure at the inlet of the reactor (psig); andc.times.84-0.05[(SV.times.C.sub.4)/P.sub.

Abstract: An improved process is provided for the production of a petrochemical by the vapor phase reaction of a hydrocarbon with an oxygen-containing gas in the presence of a suitable catalyst to produce a flammable gaseous product stream comprising the desired petrochemical, unreacted hydrocarbon, oxygen, carbon monoxide and carbon dioxide. In the improved process, a cooled or liquefied inert gas is injected as a quench fluid into the gaseous product stream exiting the hydrocarbon oxidation reactor, thereby cooling the stream to a temperature below the autoignition temperature of the flammable components of the stream, the petrochemical is recovered from the gaseous product and unreacted hydrocarbon is removed from the gaseous product and recycled to the reactor.

Abstract: This invention provides a process for the production of an anhydride by the vapor phase reaction of a hydrocarbon with substantially pure oxygen in the presence of a suitable catalyst. In the improved process, the anhydride product is removed, carbon monoxide, present in the reactor effluent as a by-product, is oxidized to carbon dioxide and part of the gaseous effluent, comprised mainly of carbon dioxide and unreacted hydrocarbon, is recycled to the reactor. Removal of carbon monoxide from the recycle stream reduces the hazard of a fire or explosion in the reactor or associated equipment. The use of carbon dioxide as the principal diluent increases heat removal from the reactor, thereby increasing the production capacity of the reactor.

Abstract: A fluid bed catalyst which has lost activity or fluidization quality through agglomeration, contamination, or a physical or chemical change on the surface of the catalyst is deagglomerated and/or its surface re-exposed, by contacting the fluidized catalyst with a high velocity gas sufficient to cause multiple collisions among the catalyst particles and thereby deagglomerating the particles and/or abrading the surface of the particles to expose fresh catalyst.

Abstract: Crude maleic anhydride produced by catalytic oxidation is distilled and then n-propyl gallate, cuprous chloride and zinc chloride are added thereto.Alternatively, crude maleic anhydride is distilled in the presence of tridecyl phosphite. Further, these procedures can be used in combination. Thermal stability and color stability of the maleic anhydride is improved.

Abstract: A process is disclosed for increasing the recovery of maleic anhydride from the product condenser. Maleic anhydride is added to the oxidation reactor gaseous effluent. Maleic acid buildup in the condenser is reduced; condenser plugging is reduced; and process run time required to build up to production rates after periodic cleaning can be reduced.

Abstract: In accordance with the process of this invention, an improved titanium dioxide rutile-based catalyst for molecular oxidation of a hydrocarbon to form the corresponding carboxylic anhydrides is prepared by the steps of (a) forming a catalyst precursor by depositing on titanium dioxide solids in the rutile form a discontinuous monolayer amount of at least one source of a Group IA metal oxide; (b) calcining the thus-formed catalyst precursor under conditions sufficient to convert the Group IA metal oxide source into the corresponding Group IA metal oxide; (c) depositing upon the calcined catalyst precursor a catalytically effective amount of at least one vanadium oxide source which is convertible into vanadium oxide upon heating; and (d) calcining the vanadium-deposited solids under conditions sufficient to convert the vanadium compound into vanadium oxide.

Abstract: In accordance with the process of this invention, an improved catalyst for molecular oxidation of a hydrocarbon to form the corresponding carboxylic anhydrides is prepared by the steps of (a) forming a catalyst precursor by depositing on titanium dioxide solids in the anatase form a discontinuous monolayer amount of at least one source of a Group VIB metal oxide; (b) calcining the thus-formed catalyst precursor under conditions sufficient to convert the Group VIB metal oxide source into the corresponding group VIB metal oxide; (c) depositing upon amount of at least one vanadium oxide source which is calcining the vanadium-deposited solids under conditions sufficient to convert the vanadium compound into vanadium oxide.

Abstract: In accordance with the process of this invention, an improved catalyst for molecular oxidation of a hydrocarbon to form the corresponding carboxylic anhydrides is prepared by the steps of (a) forming a catalyst precursor by depositing on titanium dioxide solids in the anatase form at least a monolayer amount of at least one vanadium oxide source which is convertible to vanadium oxide upon calcining; (b) calcining the thus-formed catalyst precursor under conditions sufficient to convert the tantalum oxide source into the oxide form; (c) depositing upon the calcined catalyst precursor a catalytically effective amount of at least one vanadium oxide source which is convertible into vanadium oxide upon heating and at least one metal oxide source selected from the group consisting of oxides of Sb, Ga, Ge, In, T.sub.1, Pb, Se, Te, P and Bi, which is convertible into the corresponding metal oxide upon heating and which is reactive with V.sub.2 O.sub.

Abstract: In accordance with the process of this invention, an improved catalyst for molecular oxidation of hydrocarbons to form the corresponding carboxylic anhydrides is prepared by the steps of forming a catalyst precursor by depositing on titanium dioxide catalyst solids in the anatase form a continuous monolayer amount of at least one source of titanium oxide, calcining the thus-formed catalyst percursor under conditions sufficient to convert the titanium oxide source into the oxide form, depositing upon the calcined catalyst precursor a continuous monolayer amount of at least one vanadium compound which is convertible into vanadium oxide upon heating and calcining the vanadium-deposited solids under conditions sufficient to convert the vanadium compound into vanadium oxide.

Abstract: A process for activating fluid bed catalysts useful for producing maleic anhydride from 4 carbon atom hydrocarbons is provided including contacting the fluidized catalyst containing the mixed oxides of vanadium and phosphorus with oxygen and a reducing gas at least partially combustible with oxygen at elevated temperatures sufficient to cause such combustion, wherein the molar ratio of reducing gas to oxygen is greater than the stoichiometric ratio required for complete combustion of the reducing gas. Also provided are catalysts activated by the process of the invention, as well as a process for producing maleic anhydride utilizing the catalysts thus activated.