Monsanto Company

Huntsman Petrochemical Corporation

Keppel, Robert A.

Franchetti, Victoria M.

Robert A Keppel

Michael J Mummey

Samuel J Tremont

George D Davis

Emerson H Lee

Charles R Graham

Harold Raffelson

James T Wrobleski

James W Edwards

Scott F Mitchell

Jerry R Ebner

Timothy R Felthouse

Carl J Schaefer

A Lamar Reeves

Victoria M Franchetti

John S McConaghy, Jr

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.

Prevention of catalyst attrition and tar formation in manufacture of

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. Preferably, the catalyst activity and the gas permeability of the bed vary in the direction of gas flow so that both the catalyst activity and the pressure drop per unit distance are lower in a critical region, where the combination of temperature and hydrocarbon concentration could otherwise cause the reaction to proceed at an excessive rate, than they are in a region of low temperature and low hydrocarbon concentration. Significant and unexpected improvement in reactor performance is achieved by the combination of a graded catalyst charge and incorporation of a catalyst modifying organophosphorus compound in the hydrocarbon feed.

High productivity process for the production of maleic anhydride

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.

Molybdenum-modified vanadium-phosphorus oxide catalysts for the

Production of maleic anhydride using molybdenum-modified

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. The catalyst is prepared by mixing a particulate phosphorus/vanadium oxide precursor with a pore modification agent to produce a modified catalyst precursor composition, forming the modified precursor composition into a predetermined shape, and removing the pore modification agent substantially at a temperature below 300.degree. C., preferably using air as a stripping gas.

High performance VPO catalyst and process of preparation thereof

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.

Supression of autoignition in maleic anhydride production

Shaped oxidation catalyst structures containing catalytic material comprised of mixed oxides of vanadium and phosphorus which are useful for the production of maleic anhydride via the partial oxidation of nonaromatic hydrocarbons, particularly n-butane, in the vapor phase with molecular oxygen or a molecular oxygen-containing gas are provided. Such structures are characterized by exhibiting (a) a geometric volume of from about 30 percent to about 67 percent of that exhibited by the void space-free solid geometric form, (b) an external geometric surface area/geometric volume ratio of at least about 20 cm.sup.-1, (c) a bulk density of from about 0.4 g/cm.sup.3 to about 1.4 g/cm.sup.3, and (d) a mechanical resistance sufficient to maintain substantially the structural integrity of the shaped structure under handling and use conditions.

Shaped oxidation catalyst structures for the production of maleic

Iron/lithium promoted phosphorus-vanadium-oxygen catalysts for the production of maleic anhydride are prepared by contacting a substantially tetravalent vanadium-containing compound and a phosphorus-containing compound and a promoter component containing each of iron and lithium in a substantially anhydrous alcohol medium in the presence of anhydrous hydrogen chloride to form an iron/lithium promoted phosphorus-vanadium-oxygen catalyst precursor. The catalyst precursor is recovered, dried, roasted, formed into structures if structures are desired, and calcined.

Process for the preparation of iron/lithium -promoted catalysts for the

Catalysts useful for the partial oxidation of nonaromatic hydrocarbons, particularly n-butane, with molecular oxygen or an oxygen-containing gas in the vapor phase to produce maleic anhydride are provided which comprise phosphorus, vanadium, and oxygen and a promoter component containing each of iron and lithium.

Iron/lithium--promoted catalysts for the production of maleic anhydride

Phosphorus-vanadium mixed oxide oxidation catalysts are prepared by introducing a substantially pentavalent vanadium-containing compound and a pentavalent phosphorus-containing compound into an alcohol medium capable of reducing the vanadium to a valence state less than +5 in the presence of an alcohol-modifying agent to form a phosphorus-vanadium mixed oxide catalyst precursor. The catalyst precursor is recovered, dried, formed into desired structures, and calcined at temperatures from about 250.degree. C. to about 600.degree. C. The catalysts are highly effective in that they exhibit a weight/weight productivity of at least 70 grams of maleic anhydride per kilogram of catalyst per hour.

Process for preparing phosphorus-vanadium mixed oxide oxidation catalysts

Maleic anhydride is produced by the oxidation of a non-aromatic hydrocarbon having at least four carbon atoms in a straight chain with molecular oxygen or a molecular oxygen-containing gas in the vapor phase in the presence of a phosphorus-vanadium mixed oxide oxidation catalyst. Such catalysts are prepared by introducing a substantially pentavalent vanadium-containing compound and a pentavalent phosphorus-containing compound into an alcohol medium capable of reducing the vanadium to a valence state less than +5 in the presence of an alcohol-modifying agent to form a phosphorus-vanadium mixed oxide catalyst precursor. The catalyst precursor is recovered, dried, formed into desired structures, and calcined at temperatures from about 250.degree. C. to about 600.degree. C. The catalysts are highly effective in that they exhibit a weight/weight productivity of at least 70 grams of maleic anhydride per kilogram of catalyst per hour.

Process for producing maleic anhydride

Catalysts useful for the partial oxidation of non-aromatic hydrocarbons, particularly n-butane, with molecular oxygen or a molecular oxygen-containing gas in the vapor phase to produce maleic anhydride are provided which comprise mixed oxides of phosphorus and vanadium. The catalysts are highly effective in that they exhibit a weight/weight productivity of at least 70 grams of maleic anhydride per kilogram of catalyst per hour.

Catalysts for the production of maleic anhydride

Attrition resistant bismuth-containing metal/oxygen compositions comprising the infusion and reaction product of an alumina existing in a crystal form selected from the group consisting of .gamma., .delta., .eta., and .chi. crystal forms, and mixtures thereof or that can be transformed by heat to such crystal forms, and characterized by a mean particle size from about 10 .mu.m to about 200 .mu.m, a fractional porosity of at least 0.2, a surface area of at least 150 m.sup.2 /g, and a pore diameter such that at least 10 percent of the pores are less than 55 .ANG., and at least one bismuth oxide, or compound convertible by heat to such bismuth oxide, having a maximum mean particle size of about 100 .mu.m, with the proviso that the alumina/bismuth oxide mean particle size ratio is at least 2, which bismuth oxide is susceptible of undergoing infusion and reaction with the alumina upon being subjected to temperatures of at least 0.4 T.sub.m for a time sufficient to cause infusion and reaction between the bismuth oxide and the alumina, wherein T.sub.m is the melting point of .degree.K. of the alumina, are useful in metal oxide-catalyzed reactions which involve reaction conditions of high stress, for example, vapor phase oxidations under fluidized bed conditions. The compositions are especially useful for the dehydrocoupling of toluene to yield toluene dehydrocoupled products in high yields and selectivities.

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Chesterfield, MO, United States of America

Robert A Keppel