Abstract: The invention relates to a method for oxidizing primary alcohols in order to obtain aldehydes and/or carboxylic acids. The reaction takes place in the presence of a catalyst supported on aluminium oxides or aluminium silicates and containing palladium, platinum, cobalt, rhodium, ruthenium, iridium, rhenium, optionally with co-catalysts.

Abstract: The present invention provides a catalyst composition for the production of carboxylic acids by the oxidation of the corresponding unsaturated aldehydes, and methods for making and using the catalyst compositions. The catalysts include compositions of the formula: MoaVbAlcXdYeOz wherein X is at least one element selected from W and Mn; Y is at least one element selected from Pd, Sb, Ca, P, Ga, Ge, Si, Mg, Nb, and K; a is 1; b is 0.01-0.9; c is 0<0.2; d is 0<0.5; e is 0<0.5; and z is an integer representing the number of oxygen atoms required to satisfy the valency of the remaining elements in the composition. Using the catalyst composition of the present invention, one may effectively oxidize the desired starting materials at relatively high levels of conversion, selectivity, and productivity, and with minimal side products.

Abstract: The present invention provides a method for stabilizing waste oil which is taken of each chemical apparatus of the manufacturing line of (meth)acryl acid and/or ester thereof, and treating the waste oil such as draining it out of the production apparatus, for example, a distillation tower from its bottom, sending and transporting it by a pump through a pipeline, and storing it in a storage tank in a simple manner while keeping the waste oil in a stable state. The waste oil can be stabilized by coexisting with solvent. The solvent used in the present invention is typically at least one selected from the group consisting of water, alcohol, ether, carboxylic acid, ketone, aromatic hydrocarbons, and aliphatic hydrocarbons.

Abstract: A process for vapor phase catalytic oxidation of methacrolein to produce methacrylic acid at high yield and with stability over a prolonged period is provided. The process is characterized, in the occasion of producing methacrylic acid by vapor phase catalytic oxidation of methacrolein using a fixed bed shell-and-tube reactor, in that (1) the catalyst layer in each reaction tube is divided into at least two layers in the axial direction of the tube to provide plural reaction zones, and (2) each of the reaction zones is filled with the catalyst in such a manner that the amount of the catalytically active component per unit volume of the reaction tube decreases from the gas inlet portion toward the gas outlet portion.

Abstract: In a process for the catalytic gas-phase oxidation of propene to acrolein, the reaction gas starting mixture is passed with a propene loading of ≧160 l(S.T.P.)/l·h over a fixed-bed catalyst which is housed in two spatially successive reaction zones A,B, the reaction zone B being kept at a higher temperature than the reaction zone A.

Abstract: A method of producing acrylic acid using a catalyst for acrolein oxidation reaction. Metallic salt components of the catalyst including molybdate, vanadate and tungstate are dissolved in water. An additional metallic salt component of the catalyst is added to the aqueous solution of the salts to form a suspension of the catalyst. In the suspension, the total weight of water is about 0.8 to about 5 times of the total weight of the metallic salts in the catalyst. This method of preparing suspension minimizes the amount of water required to dissolve the metallic salts, which reduces the amount of time and energy to be used in evaporating water from the suspension in the following step of obtaining catalyst. Additionally, in obtaining catalyst from the suspension prepared by this method, it is possible to avoid the deterioration of the catalytic performance since less heat is required to evaporate the water. Disclosed also is a method of producing a carrier-retained catalyst.

Abstract: Improved catalyst for use in production of methacrylic acid by vapor phase oxidation reaction and/or vapor phase oxidative dehydrogenation reaction of at least one compound selected from methacrolein, isobutylaldehyde and isobutyric acid is provided. This improved catalyst is a composition composed of (A) complex oxide containing as essential components molybdenum and phosphorus, which is per se known as a catalyst for the above reaction(s), and (B) complex oxide containing as essential components cerium and zirconium. When this improved catalyst is used, the operation for producing methacrylic acid can be stably continued over prolonged period.

Abstract: A process for producing methacrolein and methacrylic acid by catalytically oxidizing isobutylene or tertiary butanol in the presence of a catalyst comprising a compound oxide containing molybdenum, bismuth and iron as the essential components, wherein a catalytic oxidation reaction is started at a temperature of (T−3)° C. or lower wherein T° C. is defined as the boundary temperature of activation energy of a reaction for obtaining methacrolein and methacrylic acid from isobutylene using said catalyst, the reaction is continued while the reaction temperature is increased as the activity of the catalyst decreases, and an activation treatment is conducted for the catalyst at least once before the reaction temperature exceeds the boundary temperature of activation energy.

Abstract: A process is provided which can effectively inhibit occurrence o f hot spots in reaction zones or heat accumulation at the hot spots, in the occasion of producing acrolein and acrylic acid through vapor phase oxidation of propylene in the presence of a catalyst using a fixed bed shell-and-tube reactor, said catalyst having a composition represented by a general formula (1):

Abstract: A mixed metal oxide catalytic system consisting of molybdenum, vanadium, palladium, lanthanum, niobium and X, wherein X is copper and/or chromium, providing higher yields of acrylic acid and acrolein in the low temperature oxidation of propylene with a molecular oxygen-containing gas without the production of side products such as CO.

Abstract: In a process for the continuous heterogeneously catalyzed gas-phase partial oxidation of an organic compound in an oxidation reactor, whose feed gas mixture comprises, apart from the organic compound to be partially oxidized and molecular oxygen as oxidant, at least one diluent gas which is essentially inert under the conditions of the heterogeneously catalyzed gas-phase partial oxidation, where the essentially inert diluent gas consists partly of combustible gases, after passage through the oxidation reactor, the combustible constituents of the inert diluent gas present in the product gas stream leaving the oxidation reactor are not recirculated to the heterogeneously catalyzed gas-phase partial oxidation, but are put to further use for the purposes of another chemical reaction.

Abstract: The present invention is a method to produce an unsaturated carboxylic acid which includes the steps of: providing an epoxy compound; contacting the epoxy compound with carbon monoxide in the presence of a catalytically effective amount of a catalyst system comprising tin and cobalt under conditions effective for carbonylation of the epoxy; and recovering a .alpha.-.beta. unsaturated carboxylic acid product. The preferred epoxy is ethylene oxide which is reacted to acrylic acid by the method of the present invention.

Abstract: A catalyst having a high activity and mechanical strength and a process for preparing it are provided. The catalyst comprises molybdenum, vanadium, copper and antimony as essential components. The peak in X-ray diffractometry of the catalytically active component with Cu--K.alpha. line is largest at 22.2.+-.0.30.degree. (2.theta.).

Abstract: A coated catalyst which consists of a hollow cylindrical carrier and a catalytically active oxide material applied to the outer surface of the carrier, the applied catalytically active oxide material being applied in a coat thickness of from 10 to 1000 .mu.m, and having a specific catalytic surface area of from 20 to 30 m.sup.2 /g and an abrasion of <10, preferably <5, particularly preferably <0,5, % by weight in the turntable abrasion test. The catalyst is useful in the preparation of acrylic acid by the gas phase oxidation of acroleins.

Abstract: As an improvement for the process for production of acrylic acid by subjecting acrolein or an acrolein-containing gas to gas-phase oxidation with molecular oxygen in a fixed bed multitubular reactor, there is provided a novel process capable of producing acrylic acid at a high yield by suppressing the generation of heat spots in catalyst or the build-up of heat in hot spots of catalyst. The process comprises filling, in each of reactor tubes, two or more kinds of catalyst particles of different volumes so as to form a plurality of catalyst layers in the axial direction of the tube in such a manner that the particle volume of catalyst layer becomes smaller as the position of catalyst layer changes from the raw material gas inlet side of the tube to the raw material gas outlet side, each catalyst particle comprising, as the active component, a compound oxide containing at least Mo and V.

Abstract: A process for forming acids from aldehydes which comprises reacting an oxo aldehyde with water in the presence of an acid-forming catalyst and in the absence of hydrogen, and at a pressure of about 0.1 to 6.99 MPa and a temperature of about 93.degree. to 205.degree. C., thereby converting aldehyde to an oxo acid.

Abstract: Multimetal oxide compositions which comprise, as basic constituents, the elements Mo, V, W, Cu and Ni in oxidic form in certain molar ratios, and the preparation of these multimetal oxide compositions, and their use as catalysts for the gas-phase catalytical oxidation of acrolein to acrylic acid.

Abstract: A method of preparing methacrolein and/or methacrylic acid by catalytic gas phase oxidation of isobutane in the presence of a catalyst, wherein said catalyst is a catalyst containing divanadyl pyrophosphate and represented by general formula (1)P.sub.a V.sub.b X.sub.c Y.sub.d Z.sub.e O.sub.x (1)wherein P, V, and O represent phosphorus, vanadium and oxygen, respectively; X represents at least one element selected from the group consisting of cobalt and nickel; Y represents at least one element selected from the group consisting of niobium, tantalum, manganese, iron, copper, zinc, lanthanum, neodymium, samarium, cerium, zirconium, chromium, magnesium, tungsten, tin, hafnium, uranium, indium, cadmium, molybdenum, antimony, bismuth, rhodium, silver and sulfur; Z represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium; a, b, c, d, e, and x represent atomic ratios, respectively, provided that when a is 1, b is 0.2 to 2, c is 0.

Abstract: A process for the catalytic gas-phase oxidation of acrolein to acrylic acid in a fixed-bed reactor with contacting tubes, at elevated temperature on catalytically active oxides with a conversion of acrolein for a single pass of .gtoreq.95%, wherein the reaction temperature in the flow direction along the contacting tubes in a first reaction zone before the starting reaction gases containing the reactants enter the contacting tubes is from 260.degree. to 300.degree. C. until an acrolein conversion of from 20 to 40% is reached, and the reaction temperature is subsequently reduced by a total of from 5.degree. to 40.degree. C., abruptly or successively in steps or continuously along the contacting tubes until a methacrolein conversion of .gtoreq.95% has been reached, with the proviso that the reaction temperature in this secondary reaction zone is not lower than 240.degree. C.

Abstract: A process for the catalytic gas-phase oxidation of methacrolein to methacrylic acid in a fixed-bed reactor with contacting tubes, at elevated temperature on catalytically active oxides with a conversion of methacrolein for a single pass of from 40 to 95 mol%, wherein the reaction temperature in the flow direction along the contacting tubes in a first reaction zone from entry of the starting reaction gases containing the reactants into the contacting tubes is from 280 to 340.degree. C. until a methacrolein conversion of from 20 to 40% is reached, and the reaction temperature is subsequently reduced by a total of from 5.degree. to 40.degree. C., abruptly or successively in steps or continuously along the contacting tubes until a methacrolein conversion of from 45 to 95% has been reached, with the proviso that the reaction temperature in this second reaction zone is not lower than 260.degree. C.

Abstract: A process for producing methacrylic acid, which comprisesfilling a plurality of catalysts of different activities into a plurality of reaction zones which have been formed in each of the reaction tubes of a fixed bed multi-tubular reactor by dividing said reaction tube into two or more portions in the direction of tubular axis, so that the activity of catalyst is higher as the reaction zone is closer to the outlet of the reaction tube, andintroducing into the reaction zones containing the catalysts at least one compound selected from methacrolein, isobutyl aldehyde and isobutyric acid to oxidize the at least one compound with molecular oxygen or a molecular oxygen-containing gas.

Abstract: The processes for oxidation of propylene to acrolein and the oxidation of propylene to acrylic acid in two stages with acrolein as an intermediate are improved by use of essentially inert essentially anhydrous diluent gases to replace steam in the reaction streams. In particular, the use of essentially inert essentially anhydrous diluents which raise the composite heat capacity of the diluent gaas mixture to at least about 6.5 calories/(gram-mole) (.degree.C.) will improve selectivity to desired products and will reduce both the waste water load on the system and by-product formation.

Abstract: The process for oxidation of propylene to acrolein and the oxidation of propylene to acrylic acid in two stages with acrolein as an intermediate are improved by use of essentially inert essentially anhydrous diluent gases to replace steam in the reaction streams. In particular, the use of essentially inert essentially anhydrous diluents which raise the composite heat capacity of the diluent gas mixture to at least about 6.5 calories/(gram-mole) (.degree.C.) will improve selectively to desired products and will reduce both the waste water load on the system and by-product formation. Reduction in second-stage catalyst efficiency is compensated for by introducing steam to the feed to the second-stage, and/or by increasing the operating temperature of the second-stage, and/or by increasing the active surface area of the second-stage catalyst.

Abstract: The processes for oxidation of isobutylene to methacrolein and the oxidation of isobutylene to methacrylic acid in two stages with methacrolein as an intermediate are improved by use of essentially inert essentially anhydrous diluent gases to replace steam in the reaction streams. In particular, the uses of essentially inert essentially anhydrous diluents which raise the composite heat capacity of the diluent gas mixture to at least about 6.5 calories/(gram-mole) (.degree.C.) will improve selectivity to desired products and will reduce both the waste water load on the system and by-product formation.

Abstract: In a process for preparing a catalyst for producing methacrylic acid represented by the formula,P.sub.a Mo.sub.b V.sub.c Cu.sub.d Bi.sub.e X.sub.f Y.sub.g O.sub.hwherein P, Mo, V, Cu, Bi and O are phosphorus, molybdenum, vanadium, copper, bismuth and oxygen, respectively, X is at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, Y is at least one element selected from the group consisting of antimony, zinc, iron, cerium, magnesium, chromium, indium, tellurium, manganese, tin, germanium, arsenic, boron, silicon, selenium, zirconium, silver, tantalum and tungsten, a, b, c, d, e, f, g and h are an atomic ratio of each element, and when b is 12, a is 0.1 to 3, c is 0.01 to 2, d is 0.01 to 2, e is 0.05 to 1, f is 0.01 to 2 and g is 0.

Abstract: A process for producing methacrylic acid which includes subjecting methacrolein to gaseous phase catalytic oxidation using molecular oxygen and a catalyst represented by the general formula:P.sub.a Mo.sub.b V.sub.c Fe.sub.d Ce.sub.e (NH.sub.4).sub.f X.sub.g Y.sub.h Z.sub.i O.sub.jwherein P, Mo, V, Fe, Ce, NH.sub.4 and O represent phosphorus, molybdenum, vanadium, iron, cerium, ammonium group and oxygen, respectively; X represents at least one element selected from the group consisting of copper, zinc, bismuth, chromium, magnesium, silver, tantalum and lanthanum; Y represents at least one element selected from the group consisting of arsenic, antimony, zirconium, barium, manganese, germanium and tellurium; Z represents at least one element selected from the group consisting of potassium, rubidum, cesium and thallium; a, b, c, d, e, g, h, i and j each represents an atomic ratio of each element, and b is 12, a is in a range of 0.5-3, c is in a range of 0.01-3, d is in a range of 0.01-2, e is in a range of 0.

Abstract: Vapor phase catalytic oxidation of propylene into acrolein in the first step and then into acrylic acid in the second step has been improved (1) by utilizing as a diluent for the oxidation in the first step the effluent gas from the second step after the acrylic acid produced has been recovered therefrom and after it has been catalytically combusted and (2) by specifying operation conditions set in view of the recycle of the combusted "waste" gas.The improved process, embodying the present invention, has made it possible to produce a high concentration of acrylic acid as both gas and condensation and also to prolong the catalytic activity of a Mo-Bi composite oxide catalyst used for the first oxidation reaction.

Abstract: The gas phase catalytic oxidation of an unsaturated aldehyde with molecular oxygen at 200.degree. to 500.degree. C. to give the corresponding unsaturated carboxylic acid is conducted in the presence of a catalyst represented by the following formula:Mo.sub.12 P.sub.a X.sub.b Y.sub.c Z.sub.d O.sub.ewherein the subscripts represent the atomic ratios of each component and a is 0.5 to 6, b is 0.001 to 6, c is 0.2 to 6, d is 0 to 6, and e is a value determined by the valencies of the elements present in the catalyst; and Mo is molybdenum, P is phosphorus, O is oxygen, X is at least one metal selected from the group consisting of rhodium, cerium and zirconium, Y is at least one alkali metal selected from the group consisting of potassium, rubidium and cesium, and Z is at least one metal selected from the group consisting of iron, cobalt, nickel, zinc, antimony, silicon, bismuth, cadmium, uranium, manganese, copper, vanadium, niobium and tantalum.

Abstract: The present invention provides a process for the preparation of a catalyst used in the production of unsaturated carboxylic acids such as methacrylic acid by the gas phase catalytic oxidation of the corresponding unsaturated aldehydes such as methacrolein. Said catalyst is composed of a multi-component composition containing at least phosphorus, molybdenum and antimony. The present invention has attained an improvement in its catalytic performance such as conversion rate, selectivity, single-pass yield, etc. by using antimony trioxide with average particle size of no more than 0.2 micron as a starting material upon preparing said catalyst.

Abstract: This invention relates to a improved method for the production of methacrylic acid by the steps of subjecting isobutylene and/or tertiory hutanol to catalytic vapor-phase oxidation with molecular oxygen in a first reactor, then supplying the resultant gax mixture to a second reactor, a rodlike or plate like insert set being placed in the empty space of gas inlet part of the tube of said second reactor.

Abstract: The present invention relates to a process for producing methacrylic acid by oxidizing methacrolein in vapor phase with molecular oxygen or a gas containing molecular oxygen, characterized in that the oxidation is carried out in the presence of a catalyst having a composition shown by the following formula:Mo.sub.a V.sub.b P.sub.c X.sub.d Y.sub.e O.sub.fwherein Mo, V, P and O respectively represent molybdenum, vanadium, phosphorus and oxygen; X represents at least one element selected from the group consisting of potassium, rubidium, cesium, and thallium; Y represents at least one element selected from the group consisting of copper, silver, tin, thorium, germanium, nickel, iron, cobalt, titanium, rhenium, chromium, cerium, antimony and magnesium; and a, b, c, d, e and f denote the atomic ratio of respective elements where, a is 10, b is a number of 6 or less than 6 excluding 0, preferably 0.5 to 3, c is a number of 0.5 to 6, preferably 0.5 to 3, d is a number of 0.5 or less than 0.

Abstract: Propylene in admixture with molecular oxygen and steam is subjected to a two-step, vapor-phase, catalytic oxidation to convert into acrolein and then into acrylic acid. At least the first-step reaction is conducted in tubes of an apparatus of a shell-and-tube heat-exchanger type structure, and the reaction product of the first-step reaction is quenched before it is subjected to the second-step reaction. Reaction conditions in both the steps are specified.

Abstract: Disclosed is a process for producing methacrylic acid from methacrolein in high yields and at high selectivity which comprises vapor phase catalytic oxidation of methacrolein with molecular oxygen, characterized by using a catalyst represented by the formula: P.sub.a Mo.sub.b V.sub.c Cu.sub.d Zn.sub.e A.sub.f B.sub.g C.sub.h D.sub.i O.sub.

Abstract: A catalyst represented by the general formulaP.sub.a Mo.sub.b V.sub.c Fe.sub.d Cu.sub.e Z.sub.f X.sub.g Y.sub.h O.sub.iwherein X represents at least one or more of the elements selected form the group consisting of potassium, rubidium, cesium and thallium, Y represents at least one or more of the elements selected from the group consisting of tellurium, lanthanum, boron, silver, chromium, magnesium and barium, Z represents any one of the elements of zirconium or antimony, a to i denote atomic ratios of respective elements, and when b=12, a=0.3-4, c=0.01-3, d=0.01-4, e=0.01-3, f=0.01-3, g=0.01-3, h=0.001-5 and i denotes the number of oxygen atoms required for satisfying the valence number of the said ingredients, and a process for the production of methacrylic acid comprising contacting methacrolein in vapor phase in the presence of said catalyst.

Abstract: A catalyst having a heteropoly-acid structure and the general formula:Mo.sub.a V.sub.b P.sub.c Cu.sub.d X.sub.e O.sub.fwherein Mo, V, P, Cu and O represent respectively molybdenum, vanadium, phosphorus, copper and oxygen, X represents one or more elements selected from the group consisting of tin, thorium, germanium, nickel, iron, cobalt, magnesium, zinc, titanium, lead, rhenium, zirconium, and chromium, and a, b, c, d, e and f represent the atomic ratio of the elements where,a is 10b is a number of 3 or less than 3 excluding 0,c is a number of 0.5 to 3,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 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 presence of the catalyst defined above.

Abstract: A process for the production of 1,12-dodecanoic diacid by hydroformylating an olefin in the presence of a rhodium catalyst and oxidation with oxygen of the aldehyde which is thus formed wherein 1,9-decadiene is hydroformylated in the presence of hydridotris-triphenylphosphine-rhodium-carbonyl combined with triphenylphospine and/or triphenylphosphite, and the 1,12-dodecanedialdehyde which was thus formed is oxidized with oxygen in the presence of inorganic or organic Co(II) salts.

Abstract: A process for the production of 1,12-dodecanoic diacid by hydroformylating an unsaturated carboxy compound in the presence of a rhodium catalyst and oxidation of the aldehyde with oxygen, wherein undecyl-10-ene-acid is hydroformylated in the presence of hydridotristriphenylphosphine-rhodium-carbonyl combined with triphenylphosphine and/or triphenylphosphite, and the 11-formyl undecanioc acid which is thus formed is oxidized with oxygen in the presence of inorganic and organic Co(II) salts.

Abstract: A novel process for producing oxygen-containing organic compounds with high selectivity and good yield by oxidizing organic compounds under mild conditions is provided, which process comprises using as a catalyst for the oxidation, a complex (M.sub.m X.sub.n.L.sub.l) consisting of a transition metal compound (M.sub.m X.sub.n) and an organic phosphorous compound (L) as a ligand, wherein M represents a transition metal belonging to group I, group IV.about.VII or iron group in group VIII of the periodic table; X represents an anion such as a halogen; ligand L represents an organic phosphorous compound; and m and n mean a number of the atomic valence of said transition metal (ion) M and said anion X, respectively, and l means a number of said ligand.

Abstract: A process for producing methacrylic acid by vapor phase oxidation of methacrolein with molecular oxygen or molecular oxygen-containing gas in the presence of isobutylene and/or tertiary butanol and in the presence of a catalyst having a heteropolyacid structure represented by the following general formula:Mo.sub.a V.sub.b P.sub.c X.sub.d O.sub.ewherein Mo, V, P, and O represent molybdenum, vanadium, phosphorus, and oxygen respectively, X represents the coexistence of copper and aresenic and the a, b, c, d and e represent the atomic ratio of the elements where:a is 10,b is a number of 6 or less excluding 0,c is a number of 0.5 to 6,d is a number of 3 or less excluding 0, ande is a number determined depending on the valance and atomic ratio of the other elements.

Abstract: A 1,2-unsaturated carboxylic acid or its ester such as acrylic or methacrylic acid or its alkyl ester is purified to remove aldehyde impurities contained therein by treating the acid or its ester with a mercapto containing compound in the presence of an acid catalyst.

Abstract: A catalyst for the vapor-phase oxidation of an unsaturated hydrocarbon, alcohol, saturated aliphatic aldehyde or unsaturated aliphatic aldehyde having 4 carbon atoms, said catalyst comprising a molybdovanadophosphoric acid having X-ray diffraction lines (Cu-K.sub..alpha. radiation) at 2.theta.=about 26.2.degree., about 10.5.degree., about 21.3.degree. and about 30.3.degree. and a crystal structure approximating that of its salt, and said catalyst having the composition represented by the general formulaP.sub.a Mo.sub.b V.sub.c X.sub.d Y.sub.e O.sub.

Abstract: Production of acrylic acid by oxidation of acrolein with gas containing oxygen in the gas phase at elevated temperature in the presence of a catalyst which, in addition to oxygen, consists essentially of (a) molybdenum, (b) tungsten, (c) vanadium and (d) iron and/or copper. The atomic ratio of molybdenum:tungsten:iron and/or copper is 1 to 20:0.01 to 10:1 and the atomic ratio of vanadium:molybdenum is 0.2 to 6:6. Acrylic acid is an important starting material for the production of high polymers.

Abstract: In a process for preparing methacrylic acid by the vapor-phase catalytic oxidation of methacrolein or a methacrolein-containing mixture with molecular oxygen in the presence of an oxidation catalyst; the improvement wherein said process comprisesa first-stage oxidation step of oxidizing methacrolein or a methacrolein-containing mixture as a starting material,a first-stage separating step of separating the resulting methacrylic acid from the reaction product obtained in the first-stage oxidation step,a second-stage oxidation step of oxidizing the mixture containing the unreacted methacrolein and obtained in the first-stage separating step, anda second-stage separating step of separating the resulting methacrylic acid from the reaction product obtained in the second-stage oxidation step, andwith or without at least one additional oxidation step and separating step subsequent to the second-stage separating step,and wherein the conversion of methacrolein in the first-stage oxidation step is adjusted to 30-85 mole

Abstract: A catalyst composition useful for the oxidation of unsaturated aldehydes, particularly the oxidation of methacrolein to produce methacrylic acid, comprises the combination of oxides of molybdenum, copper, phosphorus, antimony, and cesium and/or calcium and optionally may include one or more of the elements Ni, Zn, Ru, Rh, Pd, Pt, As, K, Rb, Sr, Ba, Cr, V, Nb, W, Mn, Re, and rare earth metals including La.

Abstract: The present invention relates to a method for the preparation of phosphomolybdic acid based catalysts utilized in the oxidation of aldehydes to unsaturated carboxylic acids by forming a solution of hydrated phosphomolybdic acid in a substantially anhydrous alkanol, adding a base to the solution, evaporating the solution to yield a catalyst powder and thereafter drying and calcining the powder to form the active catalyst. A second method for preparation is also provided and includes the steps of forming a solution of hydrated phosphomolybdic acid in a substantially anhydrous alkanol, evaporating the solution to form a concentrate, impregnating a catalyst support material with the concentrate, contacting the impregnated support with ammonia gas in an amount sufficient to form an insoluble precipitate of ammonium alkyl phosphomolybdic acid within the pore structure of said support material and thereafter drying and calcining said impregnated support material so as to form a coated catalyst.

Abstract: A process for producing methacrylic acid by the vapor phase catalytic oxidation of methacrolein with molecular oxygen or a molecular oxygen-containing gas comprises using a catalyst of multi-elemental complex oxide having the formulaMo.sub.a P.sub.b As.sub.c Cu.sub.d Cr.sub.e X.sub.f O.sub.gwherein X represents at least one of element of Ce, Nd, W and Fe; a, b, c, d, e, f and g respectively represent atomic ratios and a=12, b=0.5 to 3.0, c=0.01 to 1.2, d=0.01 to 2.0, e=0.05 to 2.0 and f=0 to 1.0; and g is decided on the valences of the other components such as usually 37 to 58 which is prepared with or without a reduction using a dibasic carboxylic acid, an oxycarboxylic acid, mannitol or pyrogallol.

Abstract: Vapor phase process for the preparation of unsaturated aldehydes, carboxylic acids and mixtures thereof which comprises contacting a gaseous mixture of an open-chain olefin of from 3 to 8 carbon atoms, water and oxygen at an elevated temperature up to about 250.degree. with a solid catalyst comprising a catalytically effective amount of noble metal promoted by a solid acid consisting of mixed metal oxides.

Abstract: Oxidation catalysts which in addition to oxygen ions, with or without NH.sub.4.sup.+ ions, contain molybdenum, tungsten, phosphorus and antimony as basic components, in the atomic ratio Mo:W:P:Sb=12:0.1-3:0.1-4:0.1-3, and which are prepared in a conventional manner by combining molybdenum, phosphorus, antimony and tungsten compounds in aqueous solutions or suspensions, removing the water and calcining the residues, the combination being carried out at chloride ion concentrations of less than 0.3 mole per mole of molybdenum and in the presence of ions of monocarboxylic acids of 1 or 2 carbon atoms, dicarboxylic acids or hydroxycarboxylic acids, are particularly suitable for the gas phase oxidation of methacrolein to methacrylic acid.

Abstract: An oxidation catalyst wherein the catalytically active component has the general formulaMo.sub.12 P.sub.a Rh.sub.b Cu.sub.c V.sub.d Cs.sub.e X.sub.f Y.sub.g Z.sub.h O.sub.x,where X is Cr and/or Fe, Y is Nb, Z is Na, Li, K and/or Rb, a is 0.1-4, b is 0.001-1, c is 0.05-2, d is 0.05-4, e is 0.1-5, f is 0-2, g is 0-3 and h is 0-2, and x is the number of oxygen atoms required to saturate the valencies of the other constituents, is very suitable for the preparation of methacrylic acid by gas phase oxidation of methacrolein with an oxygen-containing and steam-containing gas mixture.

Abstract: The present invention relates to a method for the reactivation of phosphomolybdic acid based catalysts used for the conversion of saturated and unsaturated aldehydes to acids. The method comprises the step of feeding an oxide of nitrogen over the deactivated catalyst at a temperature of from about 100.degree. C. to about 400.degree. C. The method can be employed in the reactor by terminating the feed of reactant to the reactor, adjusting the reactor temperature as may be necessary to one suitable for reactivation and sweeping the reactor with a gas. Alternatively, the catalyst can be removed from the reactor for reactivation. Reactivated phosphomolybdic acid based catalysts are also disclosed. These catalysts have a ratio of molybdenum to phosphorus of 3:1 to 15:1 and are prepared by the process of feeding an oxide of nitrogen over the catalyst at a temperature of from about 100.degree. C. to about 400.degree. C.