Abstract: The present invention relates to a method for maintaining the activity of PMA based catalysts during reactor shutdown by flushing the reactor with an oxide of nitrogen gas at a temperature of from about 150.degree. C. to about 370.degree. C. The method can be employed in the reactor by terminating the feed of hydrocarbon to the reactor and then flushing the reactor. The method can be employed to treat PMA based catalysts having the general formula Mo.sub.x P.sub.y A.sub.a B.sub.b C.sub.c D.sub.d E.sub.e O.sub.z wherein A is selected from the group consisting of ammonium, cesium, potassium, rubidium and thallium; B is selected from the group consisting of copper and vanadium; C is selected from the group consisting of antimony, arsenic, bismuth and tellurium; D is palladium; E is aluminum, barium, calcium, cerium, chromium, cobalt, iron, magnesium, manganese, nickel tantalum, titanium, tungsten, zinc, zirconium, chlorine and/or bromine; x can be 3 to 15, y can be 1 to 1.5; a can be 0.1 to 3; b can be 0.

Abstract: A catalyst having heteropoly-acid structure and the general formula:Mo.sub.a V.sub.b P.sub.c Cu.sub.d As.sub.e X.sub.f O.sub.gwherein,X represents one or more elements selected from the group consisting of tin, lead, cerium, cobalt, iron, zirconium, thorium, tungsten, germanium, nickel, rhenium, bismuth, antimony, chromium, boron, magnesium, silver, aluminum, zinc and titanium and a, b, c, d, e, f and g represent the atomic ratio of the elements where,a is 10,b is a number of 3 or less than 3 excluding 0,c is a number of 0.5 to 6,d is a number of 3 or less than 3 excluding 0,e is a number of 3 or less than 3 excluding 0,f is a number of 0 to 3,g is a number determined depending on the valency and atomic ratio of other elements.There is also provided a process for producing methacrylic acid by oxidizing methacrolein with molecular oxygen or molecular oxygen-containing gas in the vapor phase in the presence of the catalyst defined above.

Abstract: A method for preparing attrition resistant, high percentage active component catalysts comprises using two types of silica, one of which is fumed silica, in a two stage catalyst preparation.

Abstract: Methacrylic acid is prepared by reacting methacrolein with molecular oxygen in the vapor phase at a temperature of from 230.degree. C. to 450.degree. C. in the presence of a catalyst having the formula Mo.sub.12 P.sub..alpha.' X.sub..beta.' Y.sub..gamma.' O.sub..delta.' wherein X is at least one member of the group consisting of Cs and Tl:Y is at least one member of the group consisting of Cs and Tl; Y is at least one member of the group consisting of V, Zr, Nb, Ni, Ta and Fe; .alpha.'=0.1-3; .beta.'=0.2-9; .gamma.'=0.1-7; .delta.'=36-100.

Abstract: A catalyst comprising (1) palladium, (2) phosphorus, (3) antimony, (4) X and (5) oxygen wherein X denotes at least one element selected from the group consisting of potassium, sodium, rubidium, lithium, cerium, beryllium, magnesium, calcium, vanadium, strontium, zinc, thorium and rhenium.There is also provided a process for the manufacture of methacrylic or acrylic acid by oxidizing methacrolein or acrolein with molecular oxygen in the vapor phase in the presence of the catalyst defined above.

Abstract: A novel catalyst comprising the elements Mo, V and Nb, and an oxidation process, is provided for oxidizing alpha-beta unsaturated aliphatic aldehydes in the vapor phase with molecular oxygen to produce the corresponding alpha-beta unsaturated carboxylic acid.

Abstract: A novel catalyst comprising the elements Mo, V and Ti, and an oxidation process, is provided for oxidizing alpha beta unsaturated aliphatic aldehydes in the vapor phase with molecular oxygen to produce the corresponding alpha-beta unsaturated carboxylic acid.

Abstract: A novel catalyst comprising the elements Mo, V and Ta, and an oxidation process, is provided for oxidizing alpha-beta unsaturated aliphatic aldehydes in the vapor phase with molecular oxygen to produce the corresponding alpha-beta unsaturated carboxylic acid.

Abstract: A stabilized heteropoly molybdate catalyst precursor in calcined form and containing anionic molybdenum in defect state is surface impregnated with certain metal cations. The stabilized precursor is one obtained by incorporating into the reaction product of a molybdate and a soluble phosphate, silicate or arsenate, an aqueous chloride ion and a compound of phosphotungstate, silicotungstate, vanadium arsenate, silico-arsenate, phosphovanadate, or silicovanadate, followed by drying and calcining. During the chloride ion stabilization step other metals may be optionally incorporated in forming the stabilized precursor.The obtained precursor is catalytically active in the conversion of the unsaturated aldehydes to the corresponding unsaturated carboxylic acids with or without incorporation of the metal cation during the chloride ion stabilization step.

Abstract: Process and system for cooling a reaction effluent containing volatized catalyst wherein the effluent is contacted with circulating cooled solid catalyst in dilute phase transport contact, with the volatized catalyst being condensed onto the solid catalyst.

Abstract: At least one olefinic hydrocarbon of 3 to 4 carbon atoms is oxidized catalytically in the gas phase in the presence of molecular oxygen at 200.degree.-450.degree. C. to produce the corresponding aldehyde and acid over a calcined catalyst of the formula Mo.sub.a Sb.sub.b Bi.sub.c Fe.sub.d Ni.sub.e Sn.sub.f X.sub.g Y.sub.h O.sub.i wherein X is at least one alkali metal selected from the group consisting of potassium, rubidium and cesium; Y is at least one metal selected from the group consisting of cobalt, uranium, germanium, tungsten and titanium; a to h are atomic ratios wherein a=12, b=0.2 to 20, c=0.2 to 12, d=0.2 to 12, e=0.2 to 12, f=0 to 20, g=0.01 to 4 and h=0 to 6; and i is determined according to the oxidation states of the metal atoms in the catalyst.

Abstract: In the production of acrylic acid by a two-stage, vapor-phase catalytic oxidation of propylene, a composite oxide catalyst expressed by the formula Mo.sub.a Bi.sub.b Ni.sub.c Co.sub.d Fe.sub.e Na.sub.f Mn.sub.g B.sub.h K.sub.i Si.sub.j O.sub.x is used in the first-stage reaction, which is carried out under specific reaction and operational conditions, and the second-stage reaction is carried under specific reaction and operational conditions while oxygen is supplied by a specific mode.

Abstract: The present invention relates to a process for the production of unsaturated aliphatic acids and the catalyst therefor, by the vapor phase oxidation of the corresponding unsaturated aliphatic aldehydes with molecular oxygen, optionally in the presence of steam, in the presence of an oxidation catalyst consisting of the oxides of the elements molybdenum, vanadium, and tungsten, plus at least one of the oxides selected from the group consisting of rhenium, and titanium and optionally one or more of the oxides of the elements manganese, iron, copper, tin, aluminum, cobalt, nickel, phosphorus, zinc, bismuth, silver, cadmium, niobium,arsenic, chromium, the alkali and the alkaline earth elements.

Abstract: A method for preparing acrylic acid by oxidation of acrolein over a new and improved catalyst providing conversions of acrolein of greater than 99% with yields of acrylic acid in excess of 95%. The catalyst consists essentially of the oxides of molybdenum, vanadium, chromium, copper and titanium and optionally silicon on an inert carrier. Catalysts useful in the process contain the elements previously mentioned in the atomic ratios ofMo.sub.15 V.sub.5-10 Cu.sub.2-5 Cr.sub.0.2-2 Ti.sub.

Abstract: The gas phase catalytic oxidation of an unsaturated aldehyde with molecular oxygen at 240.degree. to 450.degree. C. to give the corresponding unsaturated carboxylic acid is conducted in the presence of a catalyst of the following formula:Mo.sub.12 P.sub.a Q.sub.b R.sub.c X.sub.d Y.sub.e Z.sub.f O.sub.gwherein Mo is molybdenum, P is phosphorus, O is oxygen, Q is calcium and/or magnesium, R is at least one metal element selected from the group consisting of potassium, rubidium, cesium and thallium, X is at least one element selected from the group consisting of boron, silicon, manganese, iron, cobalt, zinc, germanium, uranium, tin, lead, chromium, titanium, tantalum, antimony, niobium and bismuth, Y is at least one metal element selected from the group consisting of vanadium, copper and nickel, Z is strontium and/or barium, and wherein the subscripts represent the atomic ratio of each component and a is 0.5 to 6, b is 0.2 to 6, c is 0.2 to 6, d is 0.

Abstract: A novel catalyst comprising the elements Mo, V and Nb is provided for oxidizing alpha-beta unsaturated aliphatic aldehydes in the vapor phase with molecular oxygen to produce the corresponding alpha-beta unsaturated carboxylic acid.

Abstract: Certain multiply promoted Sn-Sb oxides are superior catalysts for the ammoxidation of olefins to the corresponding unsaturated nitriles, the selective oxidation of olefins to unsaturated aldehydes and acids, and the oxydehydrogenation of olefins to diolefins.

Abstract: A process for producing methacrolein and methacrylic acid by oxidizing isobutyl aldehyde with molecular oxygen or molecular oxygen-containing gas in the vapor phase characterized by the use of a catalyst of heteropoly-acid or a mixture of heterpoly-acid and its salt which has the general formula:Mo.sub.a V.sub.b P.sub.c X.sub.d Y.sub.e O.sub.fwherein Mo, V, P and O represent respectively molybdenum, vanadium, phosphorus and oxygen, X represents one or more elements selected from the group consisting of copper, tin, thorium, aluminum, germanium, nickel, iron, cobalt, zinc, titanium, lead, rhenium, zirconium, cerium, chromium, bismuth and arsenic, Y represents one or more elements selected from the group consisting of potassium, rubidium, cesium and thallium and a, b, c, d, e and f represent the atomic ratio of the elements where,a is 10,b is a number of 6 or less than 6 excluding 0,c is a number of 0.5 to 6,d is a number of 3 or less than 3 excluding 0,e is a number of 0 to 0.

Abstract: Catalysts having improved attrition resistance are produced by incorporating a substantially uniform appearing coating of completely calcined, catalytically active oxide material onto an inert porous support containing sorbed aqueous silica sol. Such catalysts are useful in the gas phase oxidation of unsaturated aldehydes to unsaturated acids, especially acrolein to acrylic acid.

Abstract: The present invention relates to a method for the regeneration of deactivated PMA based catalysts by imbibing an aqueous volatile base within the pore structure of the deactivated catalyst so as to form a fluid phase within the pore structure, adding a volatile acid to the fluid phase to form a precipitate. The precipitate is thereafter dried and calcined to yield the regenerated catalyst. A second method for regeneration is also provided and includes the steps of imbibing a volatile solvent within the pore structure of the deactivated catalyst, adding a volatile acid to the system, and then adding a volatile base to the system to form a precipitate within the pore structure. The precipitate is again dried and calcined to yield the regenerated catalyst.

Abstract: A coated catalyst comprising (a) an inert carrier having a particle diameter of not less than 100 .mu.m and a surface area of up to 20 m.sup.2 /g and (b) a coating which firmly adheres to the outer surface and in the edge zone, near the surface, of the carrier particles, and which contains the catalytic material, can be prepared by applying the catalytic material in the form of a powder of particle size not more than 300 .mu.

Abstract: A novel catalyst comprising the elements Mo, V and Ta is provided for oxidizing alpha-beta unsaturated aliphatic aldehydes in the vapor phase with molecular oxygen to produce the corresponding alpha-beta unsaturated carboxylic acid.

Abstract: Catalysts which consist of a molded carrier, the surface of which is coated with an active catalyst composition of the general formula Mo.sub.12 A.sub.a B.sub.b C.sub.c D.sub.d O.sub.x, where A is V and/or W, B is Cu and/or Fe and/or Mn and/or Ni and/or Cr, C is Nb and/or Ta and/or Bi and/or Sb and/or Sn and/or Th and/or Ce and/or U, D is Li and/or Na and/or K and/or Rb and/or Cs and/or Tl and a is from 0.1 to 18, b is from 0 to 8, c is from 0 to 10, d is from 0 to 2 and x is from 36 to 135, which are particularly active and selective for the oxidation of acrolein and methacrolein with oxygen-containing gases to give acrylic acid and methacrylic acid, respectively, are obtained by first manufacturing the catalyst composition, before applying it to the carrier, from thermally easily decomposed salts of the components by mixing aqueous solutions, slurries or moist solid masses of the salts of the components, drying the mixture and calcining the dried composition at from 140.degree. to 600.degree. C.

Abstract: Methacrolein is produced by a vapor phase oxidation of isobutylene or tertiary butanol in the presence of a complex oxide catalyst having the formulaMo.sub.a Co.sub.b Fe.sub.c Bi.sub.d Tl.sub.e X.sub.f Y.sub.g Z.sub.h O.sub.iwherein X represents V and/or Nb; Y represents La and/or Ce; and Z represents Cs and/or Te and a, b, c, d, e, f, g, h and i represent atomic ratios wherein a=12; b=3 to 15; c=0.4 to 5; d=0.4 to 5; e=0.01 to 2; f=0.01 to 2; g=0 to 2; h=0 to 2; and i is determined by the valences of the non-oxygen components of the catalyst and is usually in a range of 40 to 79.

Abstract: The present invention relates to a process for the production of unsaturated aliphatic acids and the catalyst therefor, by the vapor phase oxidation of the corresponding unsaturated aliphatic aldehydes with molecular oxygen, optionally in the presence of steam, in the presence of an oxidation catalyst consisting of the oxides of the elements molybdenum, vanadium, tungsten and lanthanum, and optionally one or more of the oxides of the elements manganese, iron, copper, aluminum, cobalt, nickel, phosphorus, zinc, bismuth, silver, cadmium, niobium, arsenic, chromium, the alkali and the alkaline earth elements.

Abstract: A catalyst composition for use in preparing unsaturated carboxylic acids by the vapor-phase oxidation of unsaturated aldehydes, said catalyst composition comprising an oxide composition containing as essential ingredients (1) phosphorus, (2) molybdenum and (3) X in which X is at least one element selected from the group consisting of thallium and metals of Groups IA and II of the periodic table, characterized in that said oxide composition has a surface area of 4 to 20 m.sup.2 /g and a pore volume of 0.08 to 0.5 ml/g, whereby said catalyst composition has an excellent reproducibility of catalytic activity and a process for preparing aforesaid catalyst composition.

Abstract: C.sub.2 -C.sub.6 monocarboxylic and dicarboxylic acids are scrubbed from gas phase mixtures of such acids and water by gas absorption techniques utilizing a liquid solvent comprising a polyoxyalkylene glycol or a monoalkyl or dialkyl ether thereof. The solvent enriched with the acid is subjected to distillation to recover a substantially anhydrous acid product.

Abstract: The present invention relates to a process for the production of unsaturated aliphatic acids and the catalyst therefor, by the vapor phase oxidation of the corresponding unsaturated aliphatic aldehydes with molecular oxygen, optionally in the presence of steam, in the presence of an oxidation catalyst consisting of the oxides of the elements molybdenum, vanadium, tungsten and lanthanum, and optionally one or more of the oxides of the elements manganese, iron, copper, aluminum, cobalt, nickel, phosphorus, zinc, bismuth, silver, cadmium, niobium, arsenic, chromium, the alkali and the alkaline earth elements.

Abstract: A process for preparing methacrylic acid which comprises carrying out the catalytic vapor phase oxidation of methacrolein with a member selected from the group consisting of air and a molecular oxygen-containing gas in the presence of a novel catalytic oxide composition of the general formulaY.sub.a X.sub.b P.sub.c Mo.sub.d V.sub.e O.sub.fWherein Y is at least one metallic element selected from the group consisting of copper, cobalt, zirconium, bismuth, antimony and arsenic, X is at least one alkali metal element selected from the group consisting of sodium, potassium, rubidium and cesium, and a, b, c, d, e and f represent the atomic ratios of the several elements; and when d is 12, a is 0-10 and b is 0-10, c is 0.1-10, e is 0.1-10, and f is a value that is determined by the valences and atomic ratios of the several elements, with the proviso that the sum of a plus b is greater than zero.

Abstract: Methacrylic acid is produced by the vapor phase oxidation of methacrolein in the presence of a complex oxide catalyst having the formula:Mo.sub.a V.sub.b P.sub.c Ce.sub.d Cu.sub.e X.sub.f O.sub.gwherein X represents at least one of the elements selected from the group of Mn, Fe, Co, Sn and Te and a, b, c, d, e, f and g represent atomic ratios wherein a=12; b=0.01 to 2; c=0.1 to 3; d=0.01 to 2; e=0.01 to 2; f=0 to 2 and g is determined by the valences of the non-oxygen components of the catalyst and is usually in a range of 38 to 50. The catalyst can be optionally reduced by subjecting the metal oxide mixture to at least one reducing organic material selected from the group consisting of dibasic carboxylic acids, oxycarboxylic acids, and polyols.

Abstract: This invention relates to a process and catalyst for producing methacrylic acid by the oxidation of methacrolein. More specifically, it relates to a process for producing methacrylic acid from methacrolein by oxidizing the same with molecular oxygen or molecular oxygen-containing gas, which is characterized by the use of a composition, as a catalyst, having a heteropolyacid structure and the general formula:Mo.sub.a V.sub.b P.sub.c Al.sub.d Y.sub.e O.sub.fwherein Mo, V, P, Al and O represent respectively molybdenum, vanadium, phosphorus, aluminum and oxygen, Y represents one or more elements selected from the groups consisting of copper, tine, cobalt, iron, zirconium, thorium, lead and cerium, and suffixes a, b, c, d, e and f represent the atomic ratio of the elements where, a is 10, b is a number of 3 or less than 3 excluding 0 and, preferably, 0.5 to 2, c is a number of 0.5 to 10 and, preferably, 0.5 to 3, d is a number of 3 or less than 3 excluding 0, preferably, 0.01 to 1.

Abstract: Catalysts containing tungsten, phosphorus, vanadium, molybdenum, and promoted with at least one of the elements selected from the group selected from Sn, As, Cu, Ce, B, Cr, Fe, Ni, Co, U, Mn, Ag, Ru, Rh, Cd, Sr, In, Zn, and La have been found to be especially effective for the oxidation of unsaturated aldehydes to form the corresponding unsaturated acid.

Abstract: The present invention is a catalyst composition consisting of oxides or oxide complexes that contains catalytically significant amounts of cerium, tungsten, vanadium and molybdenum plus optionally one or more of Fe, Co, Ni, Zn, Cu, Mg, Mn, Bi, Ti, Zr, Sn, P, an alkali metal, an alkaline earth metal, lanthanum or an element of the lanthanoid series. These catalysts are especially useful for producing acrylic acid from acrolein and for producing methacrylic acid from methacrolein.

Abstract: The present invention is a catalyst composition consisting of oxides or oxide complexes that contains catalytically significant amounts of cerium, tungsten, vanadium and molybdenum plus optionally one or more of Co, Ni, Zn, Cu, Mg, Mn, Bi, Ti, Zr, Sn, P, an alkali metal, an alkaline earth metal, lanthanum or an element of the lanthanoid series. These catalysts are especially useful for producing acrylic acid from acrolein and for producing methacrylic acid from methacrolein.

Abstract: Methacrolein or acrolein is oxidized with molecular oxygen in the presence of water vapor, a catalyst containing palladium, phosphorus, antimony(optionally) and oxygen and a phosphoric acid or a compound capable of forming phosphoric acid during the reaction.

Abstract: A process is disclosed for preparing unsaturated carboxylic acids consisting essentially in reacting in the vapor phase an unsaturated aldehyde with molecular oxygen or an oxygen-containing gas, at a temperature ranging from 200.degree. to 370.degree. C., in the presence of a solid catalyst, with a contact time between 0.5 and 5 seconds, characterized in that the catalyst consists essentially of molybdenum, vanadium, cobalt, and optionally tungsten, these elements being chemically combined with oxygen and the atomic ratios of the elements being represented by the empirical formula Mo.sub.12 V.sub.a W.sub.b Co.sub.c O.sub.dA is between 1.5 and 3.0;B is between 0 and 0.5;C is between 3.5 and 5.5; andD is a number sufficient to satisfy the valences of the other elements,Said catalyst being prepared starting from aqueous solutions of soluble salts of the elements composing it, by the coprecipitation method. Preferably, the coprecipitation is effected at a pH ranging from 2 to 5 and at a temperature between 20.

Abstract: Methacrylic acid or acrylic acid are produced by the oxidation of methacrolein or acrolein, respectively, with molecular oxygen in the vapor phase in the presence of a catalytic oxide of molybdenum, phosphorus, arsenic, at least one element selected from the group consisting of Ag, Rh, Ru, and Au, oxygen, and optionally, at least one of Cd, Pt, Tl, Pd, Al, Ge, Cu, Ni, alkaline earth metal, NH.sub.4 and Cl.

Abstract: Methacrylic acid or acrylic acid are produced by the oxidation of methacrolein or acrolein, respectively, with molecular oxygen in the vapor phase in the presence of a catalytic oxide of molybdenum, phosphorus, arsenic, at least one element selected from the group consisting of U, Ti, Nb, Re, Pb, Zn, and Ga, oxygen, and optionally, at least one of Cu, a rare earth element, Ag, Ta, In, Th, Cd, Tl, alkaline earth metal, NH.sub.4, Cl, Ni, Al and Ge.

Abstract: A catalyst comprising (1) palladium, (2) phosphorus, (3) antimony, (4) X and (5) oxygen wherein X denotes at least one element selected from the group consisting of potassium, sodium, rubidium, lithium, cerium, beryllium, magnesium, calcium, vanadium, strontium, zinc, thorium and rhenium.There is also provided a process for the manufacture of methacrylic or acrylic acid by oxidizing methacrolein or acrolein with molecular oxygen in the vapor phase in the presence of the catalyst defined above.

Abstract: The gas phase catalytic oxidation of an unsaturated aldehyde with molecular oxygen at 240.degree. to 450.degree. C to the corresponding unsaturated carboxylic acid is conducted in the presence of a catalyst of the formula:P.sub.a Mo.sub.b Bi.sub.c Sb.sub.d X.sub.e Y.sub.f O.sub.gwherein Mo is molybdenum, P is phosphorus, Bi is bismuth, Sb is antimony, O is oxygen, X is at least one element selected from the group consisting of potassium rubidium, cesium and thallium; and Y is at least one element selected from the group consisting of cobalt, zinc, niobium, chromium, nickel, iron, silicon, tantalum, cadmium, uranium, manganese, copper, thorium, selenium, aluminum, titanium, tungsten and cerium, and wherein the subscripts a-g represent the atomic ratio of each component such that a is 0.5 to 6, b is 12, c is 0.01 to 6, d is 0.01 to 12, e is 0.2 to 6, f is 0.01 to 6, and g is a value which is determined by the valencies of the elements present in the catalyst.

Abstract: The present invention relates to a catalyst composition consisting of oxide complexes of vanadium, molybdenum and germanium plus an additional oxide selected from the group consisting of iron, nickel, thallium, phosphorus, indium, bismuth and the rare earths and optionally an oxide selected from the group copper, magnesium, manganese, aluminum, titanium, potassium, rubidium, cesium, niobium, tantalum, chromium, tungsten, uranium, cobalt, silver, zinc, tin, gallium, arsenic and antimony. These catalysts are especially useful for producing acrylic acid from acrolein and for producing methacrylic acid from methacrolein.

Abstract: A process is disclosed for preparing acrylic acid or methacrylic acid comprising reacting in vapor phase acrolein or methacrolein (respectively) with molecular oxygen or an oxygen-containing gas, at a temperature between 200.degree. and 350.degree. C, in the presence of a solid catalyst, and with a contact time between 0.5 and 5 seconds, characterized in that the solid catalyst comprises molybdenum, vanadium, tungsten, cobalt, chromium and oxgyen chemically combined with these elements, the atomic ratios among the aforesaid elements being represented by the empirical formula: Mo.sub.12 V.sub.a W.sub.b Co.sub.c Cr.sub.d O.sub.e, wherein:a is between 0.5 and 10,b is between 0.5 and 8,c is between 1 and 6,d is between 0.1 and 3, ande is a number sufficient to satisfy the valence requirements of the other elements;And with the further proviso that a+b+c is equal to or greater than 8.5.

Abstract: Methacrylic acid or acrylic acid are produced by the oxidation of methacrolein or acrolein, respectively, with molecular oxygen in the vapor phase in the presence of a catalytic oxide of molybdenum, phosphorus, bismuth, copper, oxygen, optionally a halogen selected from the group consisting of chlorine, bromine or iodine, and optionally, at least one element selected from the group consisting of Fe, Cr, Ni, Mn, Sb, Te, Rh, and Pd.