Abstract: In the production of maleic anhydride by the contact of a raw material gas containing an aliphatic hydrocarbon of not less than 4 carbon atoms and molecular oxygen with a vanadium-phosphorus oxide catalyst, the raw material gas is caused to allow presence therein of nitrogen and an inert gas possessing a thermal conductivity of not less than 800 (10−4Wm−1K−1) at 700 K. The gas formed by the oxidation reaction is allowed to contact an absorbent to effect recovery of the produced maleic anhydride. Maleic anhydride is recovered from produced oxidation reaction gas separated from a remained oxidation reaction gas after recovering maleic anhydride, and the saparated inert gas is circulated to the reaction zone. The catalyst capable of producing maleic anhydride with a high yield can be obtained by activating the vanadium-phosphorus oxide catalyst with the gas composition containing an inert gas possessing a thermal conductivity of not less than 800 (10−4Wm−1K−1) at 700 K.

Abstract: A carbon supported solid catalyst suitable for the vapor phase carbonylation of lower aliphatic alcohols, ethers, ester, and ester-alcohol mixtures, and desirably, methanol, to produce carboxylic acid, esters and mixtures thereof. The solid supported catalyst includes an effective amount of iridium and gold associated with a solid carbon support, and a halogen promoter.

Abstract: A process for the preparation of oxidation catalysts containing vanadium-phosphorus mixed oxides, consisting of: a) contacting a phosphorus compound with a vanadium compound in an organic solvent under conditions allowing the preparation, recovery, drying of said precursor, b) submitting the precursor, prior to calcination, to a treatment by contacting with a stream of dry inert gas containing vapors of an aliphatic anhydride, having from 4 to 8 carbon atoms, preferably acetic anhydride, at a temperature not exceeding 200° C., c) calcinating the precursor under an atmosphere containing air, steam, or inert gas or a mixture of them at a temperature between 350° C. and 550° C. at controlled rate of temperature increase during the time necessary to obtain active catalysts, d) using of said catalysts for the production of maleic anhydride by oxidation of aliphatic hydrocarbons.

Abstract: A catalytic composition useful in the catalytic-cracking of hydrocarbons is described, which contains at least one agent causing the inactivation of vanadium, which may be present in the hydrocarbons as a contaminant. These agents obtain inactivation of vanadium without substantial loss of catalytic activity and selectivity.

Abstract: The invention concerns a catalyst for hydrorefining and hydroconverting hydrocarbon feeds, comprising a mixed sulphide comprising at least two elements selected from elements with an atomic number selected from the group formed by the following numbers: 3, 11, 12, 19 to 33, 37, to 51, 55 to 83, 87 to 103, characterized in that the mixed sulphide results from a combination of at least one element the sulphide of which has a bond energy between the metal and sulphur of less than 50.+-.3 kcal/mol (209.+-.12 kJ/mol) and at least one element the sulphide of which has a bond energy between the metal and sulphur of more than 50.+-.3 kcal/mol (209.+-.12 kJ/mol), the mixed sulphide thus having a mean bond energy between the metal and sulphur which is in the range 30 to 70 kcal/mol (125 to 293 kJ/mol).

Abstract: A supported catalyst comprising a support, an anchoring agent such as an isopoly-oxymetal anion or oxometal salt thereof, and a metal complex which is useful in a wide variety on organic reactions, especially the hydrogenation of substituted .alpha.,.beta. unsaturated acids and esters, is provided. Various methods of preparing the supported catalyst of the present invention is also disclosed.

Abstract: A noble metal-free catalyst composition is obtainable bya) preparing an aqueous mixture comprisingi) a salt of at least one base metal selected from among the elements having atomic numbers 21-32, 39-42, 48-51, 57-75 and 81-83;ii) phosphate ions; andiii) at least one nitrogen source; andb) evaporating the aqueous mixture obtained and drying the catalyst composition thus formed. The catalyst composition prepared can be used for producing hydrogen peroxide and for the epoxidation of olefins.

Abstract: The aliphatic carboxylic acids, e.g., acetic acid, are selectively prepared, even on an industrial scale, by controlledly oxidizing the corresponding alkanes, e.g., ethane, with a source of oxygen, in the presence of a catalytically effective amount of an advantageously supported heteropolyacid catalyst having the formula (I):[A.sub.a B.sub.b ].sub.f [C.sub.c D.sub.d E.sub.e O.sub.x ].sup.f-(I)in which A is at least one monovalent cation selected from among hydrogen, an alkali metal, or the ammonium ion; B is VO.sup.2 +, VO.sup.3 +, an alkaline earth metal ion, or an ion of a metal of Groups VII A, VIII, I B, IV B and V B of the Periodic Table; C is Mo and/or W; D is phosphorus, arsenic, antimony, silicon, germanium and/or boron; E is vanadium, optionally in combination with at least one metal of Groups V A, VII A and VIII of the Periodic Table or chromium; f=a+.alpha.b wherein .alpha.

Abstract: A VPO catalyst precursor having the formula (VO)HPO.sub.4 aH.sub.2 OM.sub.m P.sub.p O.sub.y wherein M is at least one promoter element selected from the group consisting of elements from Groups IA, IB, IIA, IIIA, IIIB, IVA, IVB, VA, VB, VIA, VIB, and VIIIA of the Periodic Table of the Elements, and mixtures thereof, a is a number of at least about 0.3, m is a number of from about 0 to about 0.3, p is a number of from about 0 to about 0.3, any y corresponds to the amount of oxygen necessary to satisfy the valence requirements of all elements present, is activated by heating the catalyst precursor in an atmosphere selected from the group consisting of air, steam, inert gas, and mixtures thereof to a temperature not to exceed about 300.degree. C., maintaining the catalyst precursor at this temperature and providing an atmosphere containing molecular oxygen, steam, and optionally an inert gas, increasing the temperature at a programmed rate of from about 0.5.degree. C./min to about 15.degree. C.

Abstract: Alkanes are converted to unsaturated carboxylic acids by contacting an alkane with an oxidizing agent and a Wells-Dawson type heteropolyacid supported on wide pore polyoxometallate salts.

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: Alkanes are converted to unsaturated carboxylic acids by contacting an alkane with an oxidizing agent and a heteropolyacid supported on wide pore polyoxometallate salts.

Abstract: The present invention relates to a catalyst composition comprising an acid supported on carrier characterised in that said composition comprises in addition an amino compound.

Abstract: A catalyst composition and a process for using of the catalyst composition in a hydrocarbon conversion process are disclosed. The composition comprises an inorganic support, a Group VA metal or metal oxide, and optionally a Group IVA metal or metal oxide and a Group VIII metal or metal oxide. The process comprises contacting a fluid which comprises at least one saturated hydrocarbon with the catalyst composition under a condition sufficient to effect the conversion of the hydrocarbon to an olefin. Also disclosed is a process for producing the catalyst composition.

Abstract: An oxide catalyst comprising the elements Mo, V and Nb with small amounts of phosphorus, boron, hafnium, Te and/or As. The modified catalyst provides both higher selectivity and yield of acetic acid in the low temperature oxidation of ethane with molecular oxygen-containing gas. A process for the higher selective production of acetic acid by the catalytic oxidation of ethane with oxygen, in the presence of the improved catalyst.

Abstract: The present invention is a large-pore aluminophosphate or substituted aluminophosphate comprising a compositionaR:(M.sub.x Al.sub.y P.sub.z)O.sub.2wherein R represents an organic templating agent, and a=0 to 0.4, X=0 to 0.4, y=0.35 to 0.5, and Z=0.25 to 0.5 and characterized by the diffraction pattern of Table 1 and M may be Si, Ga, Ge, Co, Ni, Zn, Fe, V, Ti and mixtures thereof.

Abstract: A process for producing prussic acid by subjecting methanol to a gas-phase contact reaction with molecular oxygen and ammonia in the presence of a catalyst, wherein said catalyst is an oxide composition containing iron, antimony, phosphorus and vanadium with a content of vanadium content being at least 0.6 in terms of atomic ratio relative to iron content taken as 10, and a mixed raw material gas for the gas-phase contact reaction contains oxygen at an oxygen-to-methanol molar ratio of less than 1.6.

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

Abstract: A compound having the general formula AM.sub.1+y.sup.3+ M.sub.2-2y.sup.4+ M.sub.y.sup.5+ Si.sub.2 P.sub.6 O.sub.25, wherein A can be K, Rb, or Cs, M.sup.3+ can be Al, Ga, Cr, Fe, Sc, In, Y, lanthanide series elements, or combinations of these, M.sup.4+ can be Si, Ge, Ti, Ir, Ru, Sn, Hf, Zr, or combinations of these, M.sup.5+ can be V, Nb, Ta, or combinations of these, 0.ltoreq.y.ltoreq.1, the mean ionic radius of the M.sup.3+ cations and the mean ionic radius of the M.sup.5+ cations are each about 0.4 to 1.00 .ANG. when coordinated by six oxygen anions, and the mean ionic radii of the M.sup.4+ cations and the M.sup.5+ cations are each no greater than about 0.53+(0.30.times.the mean ionic radius of the M.sup.3+ cations). The compound can be made by a dry powder method that involves providing a homogeneous powder mixture of raw materials to form the compound, shaping the mixture into a preform, and firing the preform at a sufficient temperature and for a sufficient time to form the product compound.

Abstract: The invention provides an improved method for the production of vanadium/phosphorous mixed oxide catalysts, a vanadium +5 solid compound first being digested in an organic solvent at anhydrous conditions, water then being added and the resulting aqueous mixture containing suspended solid vanadium compound being digested to form the catalyst precursor.

Abstract: This invention relates to a process for the preparation of highly active and selective ammoxidation catalyst of formula (VO).sub.2 P.sub.2 O.sub.7 ,TiO.sub.2 or (VO).sub.2 P.sub.2 O.sub.7, Al.sub.2 O.sub.3, which process comprises refluxing a vanadium source in the presence of alcohols; adding a source of phosphorous to form vanadyl pyrophosphate hydrate (VO).sub.2 H.sub.4 P.sub.2 O.sub.9 or (VO).sub.2 P.sub.2 O.sub.7.2H.sub.2 O ; Physical mixing of (VO).sub.2 H.sub.4 P.sub.2 O.sub.9 with oxides selected from titania or alumina, and heating the resultant mixture in the presence of air at a temperature in the range of 300-600.degree.C. for a period in the range of 1 to 10 hours; and the use of said ammoxidation catalyst in the preparation of heteroaromatic nitrites.

Abstract: Vanadyl pyrophosphate oxidation catalyst precursors comprise vanadium phosphate esters of the formula(VO)(((R.sub.1-x /H.sub.x)OPO.sub.3).multidot.((ROH).sub.y /(H.sub.2 O).sub.z)wherein, R is an alkyl group capable of bonding, through oxygen, to phosphorus to form a phosphate ester; x is 0 to about 0.5; y is 0-1.0; z is 0-1.25; and y+z is 0-1.25 are particularly useful for the selective oxidation of butane to maleic anhydride and readily thermally decompose to form the vanadyl pyrophosphate oxidation catalysts.

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: The invention provides an improved method for the production of vanadium/phosphorous mixed oxide catalysts, using an organic solvent system and an additive such as dimethyl sulfoxide, the catalyst having special utility in the production of maleic anhydride.

Abstract: A process is provided which comprises using a catalyst comprises a rare earth element supported on an inorganic heat-resisting carrier, when a monoethanolamine is selectively prepared by reacting an alkylene oxide with ammonia in a liquid phase. This catalyst has excellent monoalkanolamine selectivity and heat resistance; and therefore, even when the ratio of ammonia to the alkylene oxide is lower compared with cases where other catalysts are used, an equal or more amount of the monoalkanolamine can be formed, and thus the recovery cost of the unreacted ammonia is reduced. Further, since the total amount of the feed raw materials is reduced, apparatuses for the reaction system and recovery system can be made smaller, and thus the cost of equipment is reduced.

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

Abstract: A vanadium/phosphorus mixed oxide catalyst precursor is transformed into the active catalyst for the production of maleic anhydride. The activation takes place in a fluidized bed and includes the steps of (a) initially heating the precursor; (b) further heating under superatmospheric pressure; (c) isothermal stage at superatmospheric pressure; and, finally, (d) cooling the activated catalyst obtained. Catalysts activated according to this procedure show high performance in the conversion of non-aromatic hydrocarbons 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: The present invention provides a process for the preparation of acidic aqueous solutions consisting essentially of, phosphomolybdovanadate salts. Certain processes of the present invention dissolve in water an oxide, oxoacid, or mixtures thereof, and at least one oxoanion salt of phosphorus, molybdenum, and vanadium, wherein the sum of salt cationic charges does not exceed the sum of the phosphomolybdovanadate anionic charges in the solution. Other processes of the present invention dissolve in water a) an oxide, oxoacid, oxoanion salt, or mixtures thereof of phosphorus, molybdenum, and vanadium and b) a carbonate salt, bicarbonate salt, hydroxide salt or mixtures thereof, wherein the sum of salt cationic charges does not exceed the sum of the phosphomolybdovanadate anionic charges in the solution.

Abstract: An activated porous phosphorus/vanadium oxide catalyst adapted for the catalytic oxidation of a hydrocarbon to produce a carboxylic acid anhydride. The catalyst comprises a shaped body having a volume of at least about 0.02 cc, a phosphorus content of between about 1.05 and about 1.20, a B.E.T. surface area of at least about 15 m.sup.2 /g, an average vanadium oxidation state of between about 4.06 and about 4.3, a total pore volume of at least about 0.15 cc/g, a normalized apparent shaped body density of between about 1.0 and about 2.0 g/cc, and a crush strength of at least about 4 pounds. At least about 20% of the pore volume of the catalyst is constituted of pores having a diameter between about 0.1 and about 3.3 .mu.M, and at least about 40% of the pore volume is constituted of pores having a diameter of less than about 0.1 .mu.M.

Abstract: A solid acid catalyst for paraffin conversion which consists of an acid salt of a heteropoly acid being represented by the following general formula:A.sub.x H.sub.(3-x) PY.sub.12 O.sub.40wherein A represents one ion selected from the group consisting of alkali metal ion and ammonium ion; Y represents at least one atom selected from the group consisting of W and Mo; x represents a number of 2.2 to 2.8, and a metal Group VIII, wherein the acid salt of heteroply acid has been impregnated in the metal of Group VIII, and paraffin conversion process using the same.

Abstract: This invention provides a method for preparing non-zeolitic molecular sieves using inexpensive reagents and at lower manufacturing cost. The method includes using a low density, small size particulate hydrated alumina, such as aluminum hydroxide, in place of aluminum alkoxides and other more costly reagents. The preferred particulate hydrated alumina has a density of less than 1.0 g/cm.sup.3, an average particle size of less than about 40 microns and an alkali content of less than 0.12 wt %.

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: Disclosed is a process comprising the heat treatment of certain V and Sb-containing catalysts at a lower temperature than the previous calcination temperature of the base catalyst to improve catalytic performance; the catalysts resulting from such process; and certain oxidation and ammoxidation reactions in the presence of such a catalyst.

Abstract: This invention relates to a novel catalyst for preparing methacrylic acid by gas phase oxidation of methacrolein obtained by gas phase catalytic oxidation of isobutylene or t-butanol. The catalyst is represented by the formula:P.sub.a Mo.sub.11 V.sub.b Du.sub.c X.sub.d Q.sub.e Z.sub.f O.sub.gwhereinX is at least one of potassium, rubium, cessium, and thallium;Z is at least one of lead, antimony, chromium, iron, bismuth, cerium, and zinc;Q is at least one of organic quaternary ammonium cations consisting of ##STR1## in which R, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from the group consisting of C.sub.1 -C.sub.5 alkyl or C.sub.1 -C.sub.5 substituted alkyl having functional groups;a is a number from 0.8 to 1.6;b is a number from 0.6 to 2;c is a number from 0.1 to 0.8;d is a number from 0.7 to 2.2;e is a number from 0.01 to 0.1;f is a number from 0 to 0.5; andg is a number of oxygens required to satisfy the valence requirements of the other elements present.

Abstract: In accordance with the present invention there is provided a cyclopentadienyl-type ligand represented by the formula ZA, wherein Z is a cyclopentadienyl-type group, wherein A is --YPR.sub.2, --YNR.sub.2, or --NR.sub.2, wherein Y is an alkylene group containing 1 to 24 carbon atoms, wherein each R is individually selected from alkyl groups containing 1 to 20 carbon atoms. Another aspect of the invention is to provide a metallocene represented by the formula ZAMX.sub.3, wherein Z and A are as described above, M is a Group IVB or VB transition metal, and X is a halide. Other aspects of the present invention include catalyst systems comprising the metallocenes and an organoaluminoxane, processes for preparing the above defined ligands, metallocenes and catalyst systems, and polymerization processes employing the catalyst systems.

Abstract: An activated porous phosphorus/vanadium oxide catalyst adapted for the catalytic oxidation of a hydrocarbon to produce a carboxylic acid anhydride. The catalyst comprises a shaped body having a volume of at least about 0.02 cc, a phosphorus content of between about 1.05 and about 1.20, a B.E.T. surface area of at least about 15 m.sup.2 /g, an average vanadium oxidation state of between about 4.06 and about 4.3, a total pore volume of at least about 0.15 cc/g, a normalized apparent shaped body density of between about 1.0 and about 2.0 g/cc, and a crush strength of at least about 4 pounds. At least about 20% of the pore volume of the catalyst is constituted of pores having a diameter between about 0.1 and about 3.3 .mu.M, and at least about 40% of the pore volume is constituted of pores having a diameter of less than about 0.1 .mu.M.

Abstract: A catalyst for the production of methacrylic acid by the vapor-phase catalyst oxidation and/or oxidative dehydrogenation of at least one compound selected rom the group consisting of methacrolein, isobutyl aldehyde, and isobutyric acid and a method for the production of methacrylic acid by the use of this catalyst are provided. The catalyst of this invention comprises (A) a composite oxide having Mo and P as essential components and used for the production of methacrylic acid by vapor-phase catalytic oxidation and/or oxidative dehydrogenation of methacrolein, isobutyl aldehyde, and/or isobutyric acid and (B) a solid acid having acid strength (Ho) of not more than -11.93. Since this catalyst excels in catalytic activity and service life, it allows methacrylic acid to be produced stably at a high yield for a long time.

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

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: 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: A vanadium/phosphorus mixed oxide catalyst containing not more than 0.2 wt % chloride is produced by drying chloride containing catalyst precursor at 100.degree.-180.degree. C., calcining the dried precursor, preferably under nitrogen, at 200.degree.-300.degree. C. and activating the calcined precursor at 350.degree.-550.degree. C. with a gas containing oxygen and a reducing agent such as propane, and preferably steam.

Abstract: The present invention relates to improvements of fluid bed catalysts. More particularly, the present invention relates to improvements of fluid bed oxidation catalysts useful in the preparation of maleic anhydride from C.sub.4 hydrocarbons, including n-butane. The present invention includes a process of contacting a fluid bed catalyst with a reactivating agent in a catalyst standpipe. The present invention also provides a catalyst containing the mixed oxides of vanadium and phosphorus, treated using the above process. The present invention further provides a process for producing maleic anhydride, utilizing the catalyst prepared using the above process. The present invention additionally provides for a reactor standpipe, utilized for regenerating catalyst according to the above process.