Abstract: Readily processible cluster compositions of vanadium and phosphorus are precursors to vanadium-phosphorus catalysts including vanadyl pyrophosphate and vanadylbis(metaphosphate).

Abstract: An improved process for calcination and activation of a catalyst containing mixed oxides of vanadium and phosphorus (V/P/O) involving the addition of spray dried catalyst precursor to a fluidizing oxygen containing gas at a controlled rate such that the temperature is maintained at a range of 370 to 410.degree. C. (preferably 390.+-.5.degree. C.). The catalyst precursor experiences, in addition to rapid temperature rise, dehydration/calcination at this elevated temperature in the fluidized state for an average range of residence time of less than about 4 hours at 3.5 atm of air or above, and up to 20 hours at 1 atm of air while simultaneously and continuously maintaining an average V.sub.ox of 4.55 or less. Such a process is useful in preparing a V/P/O catalyst that exhibits enhanced activity for the oxidation of n-butane to maleic anhydride. The novel process also provides an improved method for start-up of a commercial scale recirculating solids reactor.

Abstract: Improved methods and apparatus for manufacture of maleic anhydride by catalytic oxidation of n-butane or other hydrocarbon having four carbon atoms in a straight chain over a fixed catalyst bed comprising a phosphorus vanadium oxide catalyst. Movement of catalyst bodies with respect to each other and with respect to the walls of the reaction chamber is restrained so as to prevent the catalyst bodies from abrading against each other or the reactor chamber walls in a manner that would cause formation of catalyst fines. Methods and apparatus are also provided for removal of fines from a fixed catalyst bed. The methods of the invention are effective to prevent loss of catalyst from a tubular reactor, and to control degradation of solvent absorbent in a process in which maleic anhydride is separated from the reaction gas by absorption into such a solvent.

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: An improved process for the manufacture of maleic anhydride by catalytic oxidation of n-butane in which the feed flow channel to the catalytic reactor contains an autoignition suppression agent containing acid sites or trivalent phosphorus as an ignition inhibiting component. The autoignition suppression agent may also be used in other gas/liquid containment envelopes for flammable mixtures of hydrocarbons and oxygen. A novel apparatus and method are disclosed for assessing the influence of system conditions on autoignition of hydrocarbon/oxygen mixtures.

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: The invention relates to a heterogeneous vanadium-phosphorus oxide catalyst system for the selective oxidation of hydrocarbons, which may or may not be saturated, comprising a support based on one or more metal oxides, and vanadium-phosphorus oxide in an amount of from 0.01 to 45 wt. %, based on the weight of the catalyst and calculated as (VO).sub.2 P.sub.2 O.sub.7, to a process for the selective oxidation of an organic compound in the presence of a vanadium-phosphorus oxide catalyst, which process comprises an oxidation and a reduction phase, wherein a hydrocarbon is contacted with said catalyst in the reduction phase and in oxidized or non-oxidized form is adsorbed to the catalyst, whereafter the thus loaded catalyst is brought into the oxidation phase, the desired product is formed in the presence of gaseous oxygen and subsequently separated.

Abstract: This invention is directed towards an improved process for the selective gas phase oxidation of a organic reactant using a metal oxide redox catalyst, wherein the organic reactant and air feeds are at a substantially continuous level, the improvement comprising adding a fluctuating flow of oxygen at alternating relatively high and relatively low levels. The invention also teaches means by which a gas may be provided to a reaction process on a fluctuating basis.

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: A process for producing a vanadium-phosphorus oxide-containing catalyst precursor, which comprises (a) introducing into an organic solvent a vanadium alkoxide as a pentavalent vanadium compound and a phosphorus compound in the presence of a reducing agent capable of reducing the pentavalent vanadium compound to a tetravalent state, (b) hydrolyzing at least a part of the vanadium alkoxide before or after the introduction of the phosphorus compound, and (c) heating the vanadium-containing liquid medium obtained in step (b), in the presence of the phosphorus compound to reduce at least a part of vanadium to a tetravalent state.

Abstract: An improved process for calcination and activation of a catalyst containing mixed oxides of vanadium and phosphorus (V/P/O) comprising the steps of calcining a hydrated V/P/O or V/P/O- SiO.sub.2 catalyst precursor at a temperature range of 375.degree. to 400.degree. C. for sufficient time to dehydrate said catalyst precursor while simultaneously and continuously controlling the oxygen level such as to maintain the Vox in the range of 3.825 to 4.175; and then activating the dehydrated catalyst precursor by further heating at a range of 340.degree. to 500.degree. C. in the presence of a gaseous atmosphere containing n-butane at a partial pressure not exceeding 0.20 atm while simultaneously and continuously controlling the oxygen level such as to maintain the Vox in the range of 3.95 to 4.15. Such a V/P/O catalyst is useful in the preparation of maleic anhydride from n-butane.

Abstract: The present invention provides a composition of matter having the formulaA.sub.x B.sub.1-x V.sub.y C.sub.1-y P.sub.3 O.sub.10-15wherein A is Nb or Ta, B is Sb, C is Ti or Sn, and 0.ltoreq.x,y.ltoreq.1, a composition of matter having the formulaM.sub.z A.sub.x B.sub.1-x V.sub.y C.sub.1-y P.sub.3 O.sub.10-15wherein M is selected from the group consisting of Cu, Ag, Na, K, and Cs, A is Nb or Ta, B is Sb, C is Ti or Sn, and 0.ltoreq.x,y,z .ltoreq.1, a composition of matter having the formulaM.sub.z A.sub.x B.sub.1-x V.sub.y C.sub.1-y P.sub.3-n Si.sub.n O.sub.10-15wherein M is selected from the group consisting of Cu, Ag, Bi, Na, K, Rb, and Cs, A is Nb or Ta, B is Sb or As, C is Ti, Zr, Sn, or Ge, and 0.ltoreq.x,z.ltoreq.1, 0<y.ltoreq.1, and 0.ltoreq.n.ltoreq.2, and conversion processes catalyzed by at least one of the composition.

Abstract: The invention relates to vanadium/phosphorus oxide catalyst precursors useful in preparing catalysts useful in the oxidation of hydrocarbons containing 4 carbon atoms to maleic anhydride.

Abstract: A process for producing a precursor of a phosphorus-vanadium oxide catalyst for production of maleic anhydride by vapor phase oxidation of a hydrocarbon having 4 carbon atoms, which comprises reacting phosphoric acid and a pentavalent vanadium compound in an organic solvent capable of reducing at least a portion of the pentavalent vanadium to a valence state of +4, the phosphoric acid being substantially composed of orthophosphoric acid, and a phosphoric acid solution whose concentration is 88 to 96% being used as a source of the phosphoric acid; and a process for producing the catalyst comprising dry-pulverizing the catalyst precursor.

Abstract: A method of regenerating V/P/O oxidation catalyst used for the partial oxidation of n-butane which comprises terminating the n-butane feed and contacting the catalyst with an oxygen containing gas, such as air for a sufficient period of time to regenerate the catalyst such that when the n-butane feed is restarted the yield is greater than just before the treatment.

Abstract: An improved process for selective vapor phase oxidation of n-butane to maleic anhydride involving the use of a recirculating solids reactor having a reaction zone and a catalyst regeneration zone wherein n-butane is converted to maleic acid in the reaction zone by use of a vanadium/phosphorous oxide (V/P/O) catalyst in oxidized form and the reduced vanadium/phosphorous oxide catalyst is regenerated by contact with oxygen in the regeneration zone. Replenishment of the inherent catalyst losses associated with the catalyst recycling process is accomplished by adding to the catalyst in the regeneration zone vanadium/phosphorous oxide catalyst precursor at a rate of addition that effectuates in situ calcination and activation of the vanadium/phosphorous oxide catalyst precursor while simultaneously maintaining the desired operating temperature of the n-butane to maleic anhydride conversion reaction. Such a process is useful in maintaining the high operating capacity of the reactor over an extended period of time.

Abstract: This invention relates to heteropolyacids characterized by their comprising phosphorus as the heteroatom and molybdenum and/or tungsten at octahedral sites, some of the molybdenum and/or tungsten having been replaced with vanadium and at least one transition metal or main group cation, the vanadium and cation occupying the octahedral sites surrounding the phosphorus heteroatom in the heteropolyacid structure. This invention also concerns the use of these heteropolyacids as catalysts in the oxidation of n-butane to maleic anhydride.

Abstract: A catalyst for the production of maleic anhydride by oxidation of butane and a process for the production of a catalyst using phosphoric acid and glycol ether solvents.

Abstract: An oxide catalyst for producing maleic anhydride by vapor phase oxidation of a hydrocarbon having 4 carbon atoms, obtainable by (1) reacting a pentavalent vanadium compound and a pentavalent phosphorus compound in an organic solvent in the presence of a reducing agent capable of reducing the pentavalent vanadium to the tetravalent state to produce the crystalline composite oxide particles containing tetravalent vanadium and pentavalent phosphorus, (2) dry-pulverizing the obtained crystalline composite oxide particles in a high-speed gas flow, (3) mixing the pulverized particles with an aqueous solution containing tetravalent vanadium and pentavalent phosphorus to form a slurry, and (4) spray-drying the slurry and then calcining.

Abstract: A process for producing a vanadium-phosphorus oxide-containing catalyst precursor, which comprises (a) introducing into an organic solvent a vanadium alkoxide as a pentavalent vanadium compound and a phosphorus compound in the presence of a reducing agent capable of reducing the pentavalent vanadium compound to a tetravalent state, (b) hydrolyzing at least a part of the vanadium alkoxide before or after the introduction of the phosphorus compound, and (c) heating the vanadium-containing liquid medium obtained in step (b), in the presence of the phosphorus compound to reduce at least a part of vanadium to a tetravalent state.

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 vanadium/phosphorus oxide oxidation catalyst suitable for catalytic oxidation of C.sub.4 feed stock in the preparation of maleic anhydride is formed by calcining an intercalation complex of the formula VOHPO.sub.4 .multidot.0.5H.sub.2 O.multidot.({C.sub.n H.sub.2n+1 }--X).sub.z in which n has a value of from 0 to 20, z has a value of from about 1.5 to about 1.9; and X is an oxygen- or nitrogen-containing functional group operable to form hydrogen bonds with the structural P--OH and water groups of the complex.

Abstract: A phosphorus vanadium oxide catalyst for the oxidation of a C.sub.4 hydrocarbon. The catalyst comprises a shaped body having a volume, or a fixed bed comprising shaped bodies having an average volume, of at least about 0.02 cc, and contains a promoter selected from among Bi, Sb, Ge, Ti, Zr, La, Ce, Ni, Zn, U, Sn, Si or mixtures thereof. The promoter is present in a proportion that enables the catalyst to have a developed surface area of at least about 28 m.sup.2 /g, and to exhibit a weight/area productivity of at least about 3.5 mg maleic anhydride/m.sup.2 -hr and/or a weight/weight productivity of at least about 100 g maleic anhydride/kg.cat.-hr. when contacted with a gas containing 2.4% by volume n-butane in air, at a gas flow volume to catalyst weight ratio of 2180 cc/g-min., under a pressure of 1.055.times.10.sup.2 -kPa-G, and at a temperature sufficient to maintain a hydrocarbon conversion of 85 mole percent. Methods for the preparation of the catalyst include activation by ANST.

Abstract: Butane is oxidized with molecular oxygen in a dilute state by bringing a mixture of vaporized butane and air of controlled butane content into the presence of a contact vanadium-phosphorus-oxygen catalyst in a first oxidation zone under controlled pressure and temperature conditions, cooling the gaseous effluent from the first oxidation zone to a temperature in the range of 50.degree. to 300.degree. C., introducing a controlled amount of butane into the cooled gaseous effluent from the first oxidation zone, introducing said cooled butane-enriched stream into the second oxidation zone, and bringing the thus butane-enriched mixture into contact with a vanadium-phosphorus-oxygen catalyst disposed in the second zone.

Abstract: A method of removing chloride from phosphorus/vanadium/oxygen mixed oxide oxidation catalysts comprising treating a chloride containing catalyst comprising phosphorus, vanadium and oxygen with a stream of gas comprising oxygen, steam and an inert gas at flow rate and temperature and for a period of time to substantially reduce the amount of chloride in the catalyst.

Abstract: Catalysts comprising a compound of vanadium, phosphorus and oxygen which are employed in the oxidation of n-butane to maleic anhydride are protected from contamination caused by side reactions which occur between the catalyst and steel process equipment by covering the process equipment surfaces which contact the catalyst at elevated temperatures with a coating comprising aluminum oxide.

Abstract: An improvement in the oxidation catalyst used for the partial oxidation of n-butane and containing vanadium and phosphorus, zinc, lithium and molybdenum mixed oxides which comprises adding the molybdenum as a compound which is dissolved in a solvent during the manufacture of the catalyst.

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: 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: Phthalic anhydride is prepared in a multiple tube reactor provided with separate salt baths, the temperature of the salt bath used for cooling the first layer of catalyst, as regarded in the direction of flow of the reaction mixture, being from 2.degree. to 20.degree. C. higher than that of the salt bath(s) associated with the following layer(s).

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: 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 catalyst for producing maleic anhydride by oxidation of n-butane comprising V,P and additionally Mg or Zr is prepared by(a) heating a pentavalent vanadium compound in an organic medium to reduce at least a part of the pentavalent vanadium to tetravalent vanadium,(b) reacting the resulting vanadium compound with phosphoric acid in the presence of at least one of a magnesium compound and a zirconium compound to form a catalyst precursor,(c) separating the resulting catalyst precursor from the organic medium, and(d) drying and calcining the catalyst precursor.

Abstract: A process for producing a crystalline oxide of vanadium-phosphorus system, which comprises hydrothermally treating an aqueous medium containing (1) a tetravalent vanadium compound, (2) a pentavalent phosphorus compound, (3) a coordinate compound having at least two ligand atoms selected from the group consisting of oxygen atoms and nitrogen atoms and (4) a compound of at least one metal element selected from the group consisting of iron, nickel, cobalt and chromium, to form a crystalline oxide of vanadium-phosphorus system having an X-ray diffraction pattern shown in Table A:TABLE A ______________________________________ X-ray diffraction peaks (Anticathode: Cu--K.alpha.) 2.theta. (.+-.0.2.degree.) ______________________________________ 15.6.degree. 19.7.degree. 24.3.degree. 27.2.degree. 28.8.degree. 30.5.degree. 33.8.degree.

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: A continuous process is disclosed for the production of maleic anhydride by the partial oxidation of a hydrocarbon feedstock comprising n-butane in a concentration of at least 1.6 mole percent wherein a mixture of the feedstock and an oxidizing medium is contacted with a vanadium-phosphorus-oxygen catalyst wherein a solution of water and an alkyl ester of orthophosphoric acid is continually added to said feedstock, wherein ratio of water to elemental phosphorus in said alkyl ester is in the range of from about 6500:1 wt. to about 50,000:1 wt., water to phosphorus, and the differences in reaction temperature throughout the entire reaction zone is less than about 45.degree. C. (80.degree. F.).

Abstract: Vanadium pentoxide can be reduced to the +4 oxidation state from the +5 state, in the manufacture of vanadium-phosphorus-oxide catalyst precursor, (VO).sub.2 H.sub.4 P.sub.2 O.sub.9, by using phosphoric acid as the reducing agent rather than benzyl alcohol. Use of an alkyl silicate with the phosphoric acid insures the correct crystalline species, (VO).sub.2 H.sub.4 P.sub.2 O.sub.9, as indicated by X-ray diffraction.

Abstract: A catalyst comprising a phosphorus-vanadium mixed oxide and existing in the form of geometric shapes, such as tablets, provides minimum expansion of the geometric shapes under process reaction conditions, since the catalyst in the form of said geometric shapes has been heated in an inert atmosphere at a temperature within the range of about 343.degree. C. (650.degree. F.) to about 704.degree. C. (1,300.degree. F.) prior to being exposed to an oxygen-containing atmosphere at an elevated temperature. This catalyst is suitable for the oxidation of a hydrocarbon, such as benzene or n-butane, to maleic anhydride.

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 0.0005 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: 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 for producing a crystalline oxide of vanadium-phosphorus system, which comprises hydrothermally treating an aqueous medium containing (1) a tetravalent vanadium compound, (2) a pentavalent phosphorus compound, (3) a coordinate compound having at least two ligand atoms selected from the group consisting of oxygen atoms and nitrogen atoms and (4) a compound of at least one metal element selected from the group consisting of iron, nickel, cobalt and chromium, to form a crystalline oxide of vanadium-phosphorus system having an X-ray diffraction pattern shown in Table A:TABLE A ______________________________________ X-ray diffraction peaks (Anticathode: Cu-K.alpha.) 2.theta. (.+-. 0.2.degree.) ______________________________________ 15.6.degree. 19.7.degree. 24.3.degree. 27.2.degree. 28.8.degree. 30.5.degree. 33.8.degree.

Abstract: The oxidation of butane to maleic anhydride in a recirculating solids reactor using a stoichiometric excess of oxygen, a vanadium-phosphorus oxide catalyst in oxidized form, and separate regeneration of the resultant reduced catalyst is disclosed.

Abstract: Novel maleic anhydride catalysts comprising phosphorus-vanadium oxides and phosphorus-vanadium-co-metal oxides wherein said catalysts do not expand under reaction conditions for the manufacture of maleic anhydride and a process for preparing these catalysts are disclosed. The process comprises reacting a vanadium compound with a phosphoryl halide in the presence of water in an atmosphere comprising at least about 0.1% oxygen wherein the molar ratio of water to phosphorus from the phosphoryl halide is in the range of about 2.25:1 to about 3.75:1.

Abstract: A continuous process for production of maleic anhydride is disclosed wherein maleic anhydride is produced in high yield and catalyst productivity is in the range of from about 0.12 to about 0.18 pounds of maleic anyhdride produced per pound of catalyst per hour. The catalyst comprises vanadium-phosphorus-oxygen and a modifier, preferably molybdenum. The increased catalyst productivity substantially increases production rates without necessity for extensive equipment modification.

Abstract: Novel maleic anhydride catalysts comprising phosphorus-vanadium oxides and phosphorus-vandium-co-metal oxides and the process for making such catalysts are disclosed. These catalysts under reaction conditions for the manufacture of maleic anhydride from butane feedstock do not expand to the point of crushing and producing fines. Moreover, the halogen level of such a catalyst is reduced.

Abstract: A process for the manufacture of maleic anhydride using phosphorus-vanadium catalyst and peroxide modifiers.

Abstract: The present invention relates to a process for the regeneration and stabilization of certain phosphorus-vanadium-oxygen complex catalysts or phosphorus-vanadium-oxygen co-metal complex catalysts, with halogen-containing components and subsequently treating the catalyst with phosphorus compounds. These catalysts are useful for the manufacture of maleic anhydride from butane feedstock.