Abstract: A catalytic bed for the partial oxidation of n-butane to maleic anhydride which comprises at least one first catalytic layer and at least one second catalytic layer, wherein each catalytic layer consists of a vanadium and phosphorus mixed oxide (VPO) catalyst and only the catalyst of the second catalytic layer further comprises tungsten, and wherein the second catalytic layer constitutes 25% to 45% of the total length of the catalytic bed and is arranged consecutively after the first catalytic layer along the direction in which the mixture of gases comprising the oxidation reagents flows. The present invention also relates to a process for producing maleic anhydride by partial oxidation of n-butane which uses the catalytic bed.

Abstract: A pilot plant for chemical looping hydrogen generation using a single-column packed bed and hydrogen generation method. The plant has a feeding system, reaction system, tail gas treatment and analysis system, and auxiliary system. The reaction system has a packed bed reactor, inside which a thermal storage layer, oxygen carrier layer and supporting layer are arranged successively from top to bottom. The feeding system has a delivery pipe, metering pump, mass flow controller and fuel mixer. The tail gas treatment and analysis system has a cooler, gas-liquid separator, mass flow meter, gas analyzer and tail gas pipe. The packed bed reactor is subjected to fuel reduction, purge, steam oxidation, purge, air combustion and purge stages successively under control of the feeding system. The pilot plant enables evaluation for oxygen carriers and identification for technological difficulties and can generate high-purity hydrogen without using complex gas purification devices.

Abstract: An oxidation catalyst comprising vanadium, phosphorus, and oxygen having average vanadium valence less than about 4.10, and a method of preparing such catalyst, is provided. The catalyst has side crush strength of at least about 5 lbs. and improved yield of maleic anhydride from n-butane between about 1% and about 6% absolute. The catalyst is formed by exposing a conventional active VPO catalyst having average vanadium valence between about 4.10 and about 4.40 to an organic solvent having a dielectric constant between about 5 and about 55 under conditions that facilitate an oxidation-reduction reaction, reducing the valence of the vanadium below 4.10.

Abstract: The present application relates to a process for manufacturing maleic anhydride that comprising the following steps: a) fermentation of renewable raw materials and optionally purification to produce a mixture comprising at least butanol; b) oxidation of the butanol to maleic anhydride at a temperature generally between 300° C. to 600° C., using a catalyst based on oxides of vanadium and/or molybdenum; c) isolation of the maleic anhydride obtained at the end of step b). It also relates to the maleic anhydride obtained from renewable raw materials, to the copolymers and compositions comprising said maleic anhydride and also uses of use of this maleic anhydride.

Abstract: A novel polynary metal oxide phosphate of the general formula I Ma(VO)(P2O7)b(PO4)c is described, in which M is one or more metals selected from V, Ti, Zr, Hf, Cr, Fe, Co, Ni, Ru, Rh, Pd, Cu, Zn, Cd, Hg, B, Be, Mg, Ca, Sr and Ba, a is from 1.5 to 2.5, b is from 0.5 to 1.5, c is from 0.5 to 1.5, having a crystal structure whose powder X-ray diffractogram is characterized by defined reflections. A preferred representative is Fe2VO(P2O7)(PO4). The metal oxide phosphates are suitable as gas phase oxidation catalysts, for example for preparing maleic anhydride from a hydrocarbon having at least four carbon atoms.

Abstract: A process is disclosed for the improvement of fluid bed vanadium phosphorus mixed oxide catalyst performance in the manufacture of maleic anhydride from butane, which process comprises impregnating the VPO catalyst powder with a phosphorus compound, such as an alkyl ester of orthophosphoric acid and then using this impregnated catalyst powder to provide phosphorus to the maleic anhydride producing catalyst.

Abstract: An improved process for the production of maleic anhydride by the catalytic oxidation of n-butane. Maleic anhydride is produced by reacting n-butane gas with oxygen gas or an oxygen-containing gas, in the presence of a vanadium phosphorus oxide catalyst. A trialkyl phosphite or trialkyl phosphate component is continuously added to the gases in an amount of from about 0.5 ppm to about 4 ppm by weight of elemental phosphorus in the trialkyl phosphate or trialkyl phosphite component. Heat is applied to the gases at a temperature of from about 400° C. to about 440° C. while maintaining a maximum temperature of gases present in the reaction of about 480° C. A simultaneous conversion of n-butane to maleic anhydride of about 84% or more and a conversion of n-butane to by-product acrylic acid of about 1.5% or less is achieved.

Abstract: An improved process for the production of maleic anhydride by the catalytic oxidation of n-butane. Maleic anhydride is produced by reacting n-butane gas with oxygen or an oxygen-containing gas, in the presence of a vanadium phosphorus oxide (VPO) catalyst. An improved yield and selectivity in the production of maleic anhydride is attained by the addition of a substantially pure carbon monoxide gas stream in the reactant feed stream. A process is given for the production of maleic anhydride by reacting a combination of gas streams in the presence of a VPO catalyst. The combination of gas streams comprises an n-butane gas stream, an oxygen or oxygen-containing gas stream, and a substantially pure carbon monoxide gas stream. The amount of carbon monoxide present in the combination of gas streams is from about 0.5 volume % to about 6 volume % based on the total volume of the combination of gas streams.

Abstract: A new composition, SbVPO6+?, in which 0??? 1.5, has been prepared. Crystals of the compound have been grown by several methods, and the crystal structure has been determined. It is related in structure to vanadyl pyrophosphate (VPO), an important selective oxidation catalyst. The compound has shown utility as an oxidation catalyst.

Abstract: Catalysts comprising a catalytically active composition, the catalytically active composition comprising vanadium, phosphorus, iron and oxygen, wherein the catalytically active composition has an iron:vanadium atomic ratio of 0.005 to <0.05, and wherein iron in the catalytically active composition is derived from an iron starting material comprising Fe(III) phosphate; and processes for making such catalysts as well as uses therefor to prepare maleic anhydride are described.

Abstract: The absolute configuration of a chiral compound is determined by (i) coordinating the chiral compound to a metalloporphyrin having a carbon chain-crosslinked porphyrin dimer structure in which one of the two porphyrin rings has at least one ethyl or substituent bulkier than ethyl at at least one of the second peripheral carbon atoms from the carbon atom at the carbon chain crosslink site, and (ii) analyzing the resultant coordination compound by circular dichroism spectrophotometry to determine the absolute configuration of the asymmetric carbon based on the sign of the Cotton effect. The chiral compound has an asymmetric carbon bonded to a basic group capable of coordinating to the metal of the other porphyrin ring of the metalloporphyrin dimer or an asymmetric carbon atom adjacent to the carbon atom bonded to the basic group.

Abstract: Process for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of hydrocarbons having at least four carbon atoms by means of oxygen-containing gases at from 350 to 500° C.

Abstract: Active vanadium/phosphorus mixed oxide catalyst for the conversion of non-aromatic hydrocarbons, e.g., n-butane, into maleic anhydride. The catalyst is prepared from the catalyst precursor, that is, prepared by the reaction of a source of vanadium in an organic medium in the presence of a phosphorus source. The organic medium is (a) isobutyl alcohol or a mixture of isobutyl alcohol and benzyl alcohol and (b) a polyol. The catalyst precurso is transformed into the active catalyst by an activation process that includes a heat treatment that includes applying a temperature of up to 600° C.

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: The present invention is directed to gambogic acid, analogs and derivatives thereof, represented by the general Formulae I-III: wherein R1-R5 are defined herein. The present invention also relates to the discovery that compounds having Formula I-III are activators of caspases and inducers of apoptosis. Therefore, the activators of caspases and inducers of apoptosis of this invention can be used to induce cell death in a variety of clinical conditions in which uncontrolled cell growth and spread of abnormal cells occurs.

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: There is a process for producing coated catalysts for the gas-phase oxidation of C.sub.4 hydrocarbons to maleic anhydride. A vanadyl phosphate catalyst precursor is prepared having a V/P ratio of from 1:0.5 to 1:2 and a mean vanadium oxidation state of from 3.9 to 4.5. The vanadyl phosphate precursor is then calcined by heating for a several hours at a temperature of from 200.degree. C. to 500.degree. C. before being applied, in an aqueous suspension to the support bodies. Furthermore, there is the use of these coated catalysts in processes for the gas-phase oxidation of saturated or unsaturated C.sub.4 -hydrocarbons to maleic anhydride.

Abstract: An improved process for the manufacture of maleic anhydride by catalytic oxidation of a nonaromatic hydrocarbon having at least four carbon atoms in a straight chain, in which a gas containing oxygen and hydrocarbon is passed through a fixed catalyst bed in a tubular reactor. The activity of the catalyst bed is graded in such manner that the reactor can be operated at an initial (feed gas) hydrocarbon concentration of over 1.5% by volume, an integrated average temperature difference between gas and cooling fluid of at least about 15.degree. C. over that portion of the bed in which the gas temperature exceeds the cooling fluid temperature, and a productivity of at least about 5.0 lbs. maleic anhydride per hour, without the temperature difference between the gas and the cooling fluid exceeding 80.degree. C. at any point in the catalyst bed during the course of the reaction.

Abstract: A vanadium-phosphorus oxide having an X-ray diffraction spectrum (Cu--K.alpha.) showing main peaks of the diffraction angle 2.theta.(.+-.0.2.degree.) at 18.5.degree., 23.0.degree., 28.4.degree., 29.9.degree., and 43.1.degree. and having the intensity ratio of the peaks of the diffraction angle 2.theta.(.+-.0.2.degree.) at 23.0.degree. and 28.4.degree. in the following range0.3.ltoreq.I (23.0)/I (28.4).ltoreq.0.7wherein I (23.0) and I (28.4) respectively represent the intensities of the peaks of the diffraction angle 2.theta.(.+-.0.2.degree.) at 23.0.degree. and 28.4.degree., a method for the production of the oxide, a catalyst for use in a vapor phase oxidation formed of the oxide, and a method for the partial vapor phase oxidation of a hydrocarbon.

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

Abstract: An active catalyst having a crystal structure corresponding to that of a catalyst that has been prepared and activated by the following process. A substantially pentavalent vanadium-containing compound is reacted with a pentavalent phosphorus-containing compound in an alcohol medium capable of reducing the vanadium to an oxidation state of less than +5. Molybdenum is incorporated into the product of the reaction, thereby forming a solid molybdenum-modified precursor composition. The alcohol is removed to produce a dried solid molybdenum-modified precursor composition. Shaped bodies comprising said dried solid molybdenum-modified precursor composition are formed. The dried formed molybdenum-modified catalyst precursor composition is activated to transform it into the active catalyst.

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: 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: This invention relates to cation substituted catalysts based primarily upon vanadium pyrophosphate, useful in the oxidation of alkane hydrocarbons.

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 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 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: 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: The present invention provides a process for the manufacture of maleic anhydride by the vapor phase catalytic oxidation of n-butane with molecular oxygen by the use of a specially prepared phosphorus vanadium-oxygen composite catalyst containing specific kind of a divalent metal. The catalyst used in the present invention is prepared from a mixture of vanadyl hydrogen orthophosphate and at least one compound selected from the group consisting of a divalent metal hydrogen orthophosphate (Divalent metal is selected from Mg, Ca, Ba, Mn, Fe, Co, Ni, Cu, and Zn.), a divalent metal ammonium orthophosphate (Divalent metal is the same as above.), and a divalent metal orthophosphate (Divalent metal is the same as above.), with the atomic ratio of the divalent metal/vanadium of 0.003-0.5, by calcining the mixture at 300.degree.-400.degree. C., and then pretreating said catalyst in an inert gas or a mixed gas containing n butane and molecular oxygen at 350.degree.-700.degree. C.

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 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: 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: 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.