Abstract: The present invention is for a process for making a heteropoly acid compound catalyst for oxidation of unsaturated aldehydes, such as methacrolein, to unsaturated carboxylic acids, such as methacrylic acid, said catalyst containing oxides of molybdenum, phosphorus, and M?, wherein M? is cesium, potassium, rubidium, or sodium, and bismuth. The process is a synthesis of the catalyst with specific process conditions for addition of the bismuth compound as an aqueous slurry without nitric acid. A catalyst precursor is formed by removing the water and drying the solid particles. The heteropoly acid compound catalyst is formed by calcination of the catalyst precursor.

Abstract: Supports having a catalytic coating comprising at least one porous and cavity-containing catalyst layer are described, cavities being irregular spaces having dimensions greater than 5 ?m in at least two dimensions or having cross-sectional areas of at least 10 ?m2. The catalytic coatings are distinguished by a high adhesive strength and can preferably be used in microreactors.

Abstract: A catalyst for the epoxidation of an olefin comprising a carrier and, deposited on the carrier, silver, a rhenium promoter, a first co-promoter, and a second co-promoter; wherein the quantity of the rhenium promoter deposited on the carrier is greater than 1 mmole/kg, relative to the weight of the catalyst; the first co-promoter is selected from sulfur, phosphorus, boron, and mixtures thereof; the second co-promoter is selected from tungsten, molybdenum, chromium, and mixtures thereof; and the total quantity of the first co-promoter and the second co-promoter deposited on the carrier is at most 3.8 mmole/kg, relative to the weight of the catalyst; a process for preparing the catalyst; a process for preparing an olefin oxide by reacting a feed comprising an olefin and oxygen in the presence of the catalyst; and a process for preparing a 1,2-diol, a 1,2-diol ether, a 1,2-carbonate, or an alkanolamine.

Abstract: A catalyst for hydrotreating a hydrocarbon feed has been developed. The catalyst comprises a metal phosphide and promoter metal component as the catalytic component. At least a portion of the metal promoter component is deposited on the metal phosphide. The metal phosphide/promoter metal component combination is dispersed on a refractive inorganic oxide support. An example of this catalyst is where the metal phosphide is nickel phosphide, the promoter metal is molybdenum and the support is alumina. Methods of preparing the catalyst and hydrotreating processes using the catalyst are also described.

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

Abstract: A process for charging a longitudinal section of a catalyst tube with a homogeneous fixed catalyst bed section whose active composition is at least one multielement oxide or comprises elemental silver on an oxidic support body and whose geometric shaped catalyst bodies and shaped inert bodies have a specific inhomogeneity of their longest dimensions.

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

Abstract: The present invention relates to processes for improving or optimizing a catalyst for the preparation of phthalic anhydride by gas-phase oxidation of o-xylene and/or napthalene, which comprises the following steps: a) provision of a starting catalyst (C) comprising at least one first catalyst zone located towards the gas inlet and a second catalyst zone located closer to the gas outlet, with the catalyst zones preferably each having an active composition comprising TiO2; b) replacement of part of the first catalyst zone by an upstream zone of a catalyst having a higher activity than the first catalyst zone in order to provide an improved catalyst. Furthermore, an improved catalyst obtainable by this process is described.

Abstract: The invention is a supported or bound heteropoly acid catalyst composition, a method of making the catalyst composition and a process for the oxidation of saturated and/or unsaturated aldehydes to unsaturated carboxylic acids using the catalyst composition. The catalyst composition has a heteropoly acid component containing molybdenum, vanadium, phosphorus and cesium and support/binder having a surface area of about 0.1 m2/g to about 1.0 m2/g. The catalyst is made by dissolving compounds of the components of each of the heteropoly acid compounds in a solution, precipitating the heteropoly acid compounds, contacting the heteropoly acid compounds to form a catalyst precursor and calcining the catalyst precursor to form a heteropoly acid compound catalyst. Unsaturated aldehydes, such as methacrolein, may be oxidized in the presence of the heteropoly acid compound catalyst to produce an unsaturated carboxylic acid, such as methacrylic acid.

Abstract: A composition, containing vanadium, phosphorus and a support is disclosed. A method of preparing such composition is also disclosed. The composition is employed in a process to remove a heavy metal from a gaseous feed stream which can optionally include a separate heavy metal adsorption stage.

Abstract: A transition metal complex having the following Formula (A): wherein the monovalent groups R1 and R2 are —Ra, —ORb, —NRcRd, and —NHRe: the monovalent groups Ra, Rb, Rc, Rd and Re, and the divalent group R3 are (i) aliphatic hydrocarbon, (ii) alicyclic hydrocarbon, (iii) aromatic hydrocarbon, (iv) alkyl substituted aromatic hydrocarbon (v) heterocyclic groups and (vi) heterosubstituted derivatives of said groups (i) to (v); M is a Group (3) to (11) or lanthanide metal; E is phosphorus or arsenic; X is an anionic group, L is a neutral donor group; n is (1) or (2), y and z are independently zero or integers, such that the number of X and L groups satisfy the valency and oxidation state of the metal M. n is preferably (2) and the two resulting R1 groups are preferably linked.

Abstract: A method for producing a catalyst by contacting a mixed metal oxide catalyst with water, and optionally, an aqueous metal oxide precursor to produce a modified mixed metal oxide, and calcining the modified mixed metal oxide.

Abstract: The present invention relates to a method for preparing polycarbonate resin, and more particularly to a method for effectively preparing polycarbonate resin having a large molecular weight in a short time under a melt polymerization condition using a catalyst system comprising phosphoranylidene ammonium salts, which is stable and maintains superior reactivity during melt polymerization and solid state polymerization.

Abstract: A method for producing a hydrorefining catalyst of the present invention has a step of preparing an aluminum solution containing phosphorus in a molar ratio of 0.001 to 0.05 with respect to aluminum; a step of neutralizing the prepared aluminum solution to produce a pseudo-boehmite powder; a step of forming the pseudo-boehmite powder followed by performing calcination at a temperature of not less than 650° C. to obtain a carrier; and a step of carrying a hydrogenation-active metal on the pseudo-boehmite powder or the carrier. The dispersion of the concentration distribution of phosphorus in the carrier of the obtained catalyst is within 10%. This method makes it possible to obtain the hydrorefining catalyst which has a practically sufficient mechanical strength and which has an excellent activity.

Abstract: The present invention relates to a composition of metal-incorporated VSB-5 molecular sieve with nanopores and its preparation method, in particular, to a composition of a metal-incorporated VSB-5 molecular sieve with a framework of VSB-5 molecular sieve comprising nickel, phosphorous, oxygen and metal, which is useful in various fields such as a hydrogen storage material, an optical and electric/electronic material, a sensor, a catalyst, a catalyst supporter and an adsorbent, and its preparation method performed in such a manner that a specific metal component is added in a predetermined mole ratio to a reaction mixture comprised of nickel and phosphorous compounds and the resultant mixture is crystallized in the presence of inorganic or organic base as a pH modifier to yield a metal-incorporated VSB-5 molecular sieves in an economical and efficient manner.

Abstract: The invention is directed to methods of transfering catalyst particles into and within reaction systems. The reaction systems are those that use catalysts that comprise molecular sieves, particularly metalloaluminophosphate molecular sieves, especially metalloaluminophosphate molecular sieves which are susceptible to loss of catalytic activity due to contact with water molecules. The transfer methods provide appropriate mechanisms for transporting catalyst into and within a reactor to protect against loss of catalytic activity that can occur due to contact with water molecules.

Abstract: A process for preparing a vanadium, phosphorus, and oxygen catalyst precursor for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a hydrocarbon having at least four carbon atoms, which comprises (a) reacting vanadium pentoxide with from 102 to 110% strength phosphoric acid in the presence of a primary or secondary, noncyclic or cyclic, unbranched or branched, saturated alcohol having from 3 to 6 carbon atoms in a temperature range from 80 to 160° C.; (b) isolating the precipitate formed; (c) setting an organic carbon content of ?1.1% by weight in the isolated precipitate by heat treatment in a temperature range from 250 to 350° C., the heat-treated product, following the addition of 3.0% by weight of graphite, giving a powder X-ray diffraction diagram which in the 2? region features a ratio of the height of the peak of any pyrophosphate phase present at 28.5° to the height of the peak due to the graphite at 26.6° of ?0.

Abstract: A process for preparing a vanadium, phosphorus, and oxygen catalyst precursor for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a hydrocarbon having at least four carbon atoms, by reacting vanadium pentoxide (I) in the presence of a primary or secondary, noncyclic or cyclic, unbranched or branched, saturated alcohol having from 3 to 6 carbon atoms (II) with a pentavalent or trivalent phosphorus compound (III) in a temperature range from 80 to 160° C. with stirring and subsequently filtering the resultant suspension, in which (a) the way in which the phosphorus compound (III) and the vanadium pentoxide (I) are combined in the presence of the alcohol (II), (b) the action of a stirring power of from 0.01 to 0.6 W/kg suspension, and/or (c) the filtration at a temperature from 65° C. to 160° C.

Abstract: Provided is a novel heteropolyacid catalyst useful for partial oxidation of methacrolein (MACR) to methacrylic acid (MAA), as represented by the following formula 1: PMoaAbBcCdDeEfOg??(1) wherein A, B, C, D, E, a, b, c, d, e, f, and g are as defined in the specification. Provided is also a method for producing the heteropolyacid catalyst. The heteropolyacid catalyst produced by the method exhibits excellent catalyst activity in terms of conversion rate, selectivity, and yield.

Abstract: Disclosed is a method for producing a catalyst containing vanadium, phosphorus, and oxygen, which is used for oxidizing the gas phase of a hydrocarbon having at least four carbon atoms to maleic anhydride. According to the inventive method, a corresponding catalyst precursor which contains vanadium, phosphorus, and oxygen and is provided with particles having an average diameter of at least 2 mm is converted into a catalytically active form by means of calcination, and a flow of the catalyst precursor is transported on a conveyor belt across at least one calcination area over a distance 1n at an essentially steady speed in order to be calcinated. The variation over time of the gas temperature in relation to the set point value amounts to ?5° C.

Abstract: Hydrothermally synthesized catalysts comprising a mixed metal oxide are utilized to produce unsaturated carboxylic acids by the vapor phase oxidation of an alkane, or a mixture of an alkane and an alkene, in the presence thereof; or to produce unsaturated nitriles by the vapor phase oxidation of an alkane, or a mixture of an alkane and an alkene, and ammonia in the presence thereof.

Abstract: The present invention relates to a method for preparing a heteropolyacid catalyst and method for preparing methacrylic acid using thereof. More particularly, the present invention relates to a method for preparing heteropolyacid catalyst, which is produced by the recrystallization of a heteropolyacid and/or its salt dissolved in a basic organic solvent and heat-treatment, and further to a method for preparing metachrylic acid using thereof, wherein the use of the heteropolyacid catalyst increases the activity of oxidation reaction induced by the modified electronic properties of heteropolyanions and provides high efficiency production of methacrylic acid from methacrolein, since the basic property of solvent inhibits peculiar acidic property of heteropolyacid.

Abstract: A catalyst comprising a mixed metal oxide is useful for the vapor phase oxidation of an alkane or a mixture of an alkane and an alkene to an unsaturated carboxylic acid and for the vapor phase ammoxidation of an alkane or a mixture of an alkane and an alkene to an unsaturated nitrile.

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

Abstract: A catalyst composition for the selective conversion of an alkane to an unsaturated carboxylic acid having the general formula: MoVaNbbAgcMdOx wherein optional element M may be one or more selected from aluminum, copper, lithium, sodium, potassium, rubidium, cesium, gallium, phosphorus, iron, rhenium, cobalt, chromium, manganese, arsenic, indium, thallium, bismuth, germanium, tin, cerium or lanthanum; a is 0.05 to 0.99, b is 0.01 to 0.99, c is 0.01 to 0.99, d is 0 to 0.5 and x is determined by the valence requirements of the other components of the catalyst composition. This catalyst is prepared by co-precipitation of compounds of molybdenum, vanadium, niobium, silver and M to form a mixed metal oxide catalyst. This catalyst can be used for the selective conversion of an alkane to an unsaturated carboxylic acid in a one-step process or the ammoxidation of alkanes and olefins.

Abstract: The present invention concerns a method for enhancing the activity of vanadium phosphorus oxide (VPO) catalysts. Promoter reagents are grafted onto or reacted with the catalyst surface. An optional calcination and activation heating cycle transforms the catalyst precursor into a final active phase. A preferred VPO catalyst produced has a ratio of molybdenum to vanadium on the surface of the catalyst to molybdenum to vanadium in the overall bulk of the catalyst represented by the equation (Mo/V) Surface?1.10 (Mo/V) overall bulk.

Abstract: A method for manufacturing of an attrition resistant vanadium/phosphorous oxide catalyst involving forming an aqueous slurry comprising; vanadium/phosphorous oxide catalyst or vanadium/phosphorous oxide catalyst precursor particles, an aqueous solution of H3PO4, and optionally an aqueous colloidal silica sol, an aqueous polysilicic acid solution or mixture thereof and then spray drying the slurry to form attrition resistant catalyst precursor followed by calcining/activating the spray dried precursor. Such a catalyst is particularly useful in oxidation processes such as the catalytic air oxidation of butane to maleic anhydride.

Abstract: A molybdenum-based precipitate is prepared according to a process including the first step of forming a crude precipitate by pH adjustment to 6.5 or less in the presence of an alkali metal compound, and the second step of dissolving the crude precipitate in aqueous ammonia and forming a precipitate by pH adjustment to 6.5 or less. Then, the resulting molybdenum-based precipitate is washed with an acid aqueous solution having a pH of 6.5 or less and containing not less than 0.01 mole/L of ammonium root. Thus, a change in average particle diameter can be suppressed and good workability can be achieved, so that a molybdenum-based precipitate having a high purity and a desired average particle diameter can be obtained.

Abstract: A process for preparing a catalyst for maleic anhydride production wherein a +5 vanadium compound such as V2O5, an anhydrous phosphoric acid, and optionally promoters are admixed in an organic alcohol solvent, the admixture is rapidly brought to reflux and thereafter refluxed to reduced the vanadium compound to the desired degree, the reflux mixture is cooled, precursor crystals are separated by filtration and then dried and calcined.

Abstract: A catalyst, a method for producing the same, and a method for treating an exhaust gas are described. The catalyst comprises an oxide containing titanium, vanadium, phosphorus and oxygen.

Abstract: A process for preparing a catalyst for maleic anhydride production wherein a +5 vanadium compound such as V2O5, an anhydrous phosphoric acid, and optionally promoters are admixed in an organic alcohol solvent, the admixture is rapidly brought to reflux and thereafter refluxed to reduced the vanadium compound to the desired degree, the reflux mixture is cooled, precursor crystals are separated by filtration and then dried and calcined.

Abstract: The present invention includes a catalyst having (a) a non-metallic support having a plurality of pores; (b) a metal heteropoly acid salt that is insoluble in a polar solvent on the non-metallic support; wherein at least a portion of the metal heteropoly acid salt is dispersed within said plurality of pores. The present invention also includes a method of depositing a metal heteropoly acid salt that is insoluble in a polar solvent onto a non-metallic support having a plurality of pores.

Abstract: The present invention relates to a catalyst for producing methacrylic acid by the vapor-phase catalytic oxidation of methacrolein, comprising Mo, V, P and Cu as the indispensable active components, wherein copper acetate is used for all or a part of the necessary amount of a material for said Cu, a coated catalyst and a method for manufacturing the coated catalyst, and methacrolein is reacted in a high conversion and methacrylic acid is produced in a high selectivity by use of the catalyst of the present invention, and the catalyst can be used for reaction under high loading condition.

Abstract: A catalyst used in a process for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a hydrocarbon having at least four carbon atoms by means of oxygen-containing gases comprises a catalytically active composition comprising vanadium, phosphorus and oxygen and has a essentially hollow cylindrical structure in which (a) the ratio of the height h to the diameter of the continuous hole d2 is not more than 1.5 and (b) the ratio of the geometric surface area Ageo to the geometric volume Vgeo is at least 2 mm−1.

Abstract: A process for producing a catalyst for use in producing a lower aliphatic carboxylic acid ester. The catalyst is used in reacting a lower olefin with a lower aliphatic carboxylic acid in a gas phase to produce a lower aliphatic carboxylic acid ester. The process comprises the following first and second steps. The first step is a step of loading one or more heteropolyacid on a support to obtain a heteropolyacid supported catalyst. The second step is a step of contacting the heteropolyacid supported catalyst obtained in the first step with a gas containing at least one member selected from the group consisting of water, a lower aliphatic carboxylic acid and a lower aliphatic alcohol to obtain a catalyst for use in producing a lower aliphatic carboxylic acid ester.

Abstract: An orthorhombic phase mixed metal oxide is produced selectively in quantitative yield.

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

Abstract: The present invention relates to the effective utilization of a used catalyst containing at least molybdenum, an A element (at least one element selected from the group consisting of phosphorus and arsenic) and an X element (at least one element selected from the group consisting of potassium, rubidium and cesium), and provides a process for producing a catalyst, which comprises dispersing said used catalyst in water, adding thereto an alkali metal compound and/or ammonia solution, adjusting the resulting mixture to pH 6.5 or less to generate a precipitate containing at least molybdenum and the A element, and using the precipitate as a material for catalyst-constituting elements.

Abstract: The present invention relates to a process for preparing vanadyl pyrophosphate catalyst with improved structural characteristics for the selective oxidation of butane to maleic anhydride.

Abstract: A novel intercalation compound is provided, in which compound monohydric alcohol is intercalated between layers of a layered compound comprising vanadium, phosphorus and oxygen as primary components, characterized in that the monohydric alcohol is aliphatic secondary monohydric alcohol, alicyclic monohydric alcohol, or aromatic monohydric alcohol. By heating the intercalation compound, a vanadium-phosphorus mixed oxide having a BET specific surface area of at least 80 m2/g can be obtained.

Abstract: A method for preparing methacrylic acid at high selectivities and high yields by catalytically vapor phase oxidizing isobutane is provided. In the method, a catalyst comprising (i) a sparingly water-soluble salt of a hetero poly acid and (ii) a composite oxide containing phosphorus, molybdenum and vanadium is used. Component (i) preferably has the element composition (but excluding oxygen) represented by the general formula AaBbMocWdVe (wherein A is a counter cation, for example cesium, B is the hetero atom of the hetero poly acid, for example silicon, and a, b, c, d and e represent an atomic ratio of the respective elements.), and component (ii) preferably has the element composition represented by the general formula PpMoqVrXsOt (wherein X is for example cesium, and p, q, r, s and t represent an atomic ratio of the respective elements.).

Abstract: A process for preparing an antimonate-based mixed metal oxide catalyst in a catalytically active oxidized state, wherein the catalyst is represented by the empirical formula MeaSbbXcQdReOf, wherein Me, X, Q, R, a, b, c, d, e, and f are as defined herein, comprising (a) contacting an aqueous Sb2O3 slurry with HNO3 and one or more Me compounds, and, optionally, one or more compounds selected from X, Q, or R compounds to form a first mixture; (b) heating and drying the first mixture to form a solid product; and (c) calcining the solid product to form the catalyst, the catalysts prepared by the process, and the use of the catalysts in ammoxidation and oxidation processes. The catalysts of the invention are particularly useful for the production of acrylonitrile from propylene, ammonia, and an oxygen-containing gas.

Abstract: A process for the preparation of a vanadium/phosphorus mixed oxide catalyst precursor is described, comprising the reaction of a vanadium source in selected organic media in the presence of a phophorus source. The medium comprises: (a) isobutyl alcohol or a mixture of isobutyl alcohol and benzyl alcohol and (b) a polyol in the weight ratio (a) to (b) of 99:1 to 5:95. After its activation, the vanadium/phosphorus mixed oxide catalyst precursor is an excellent catalyst in the conversion of non-aromatic hydrocarbons like n-butane to malic anhydride.

Abstract: Hydrothermally synthesized catalysts comprising a mixed metal oxide are utilized to produce unsaturated carboxylic acids by the vapor phase oxidation of an alkane, or a mixture of an alkane and an alkene, in the presence thereof; or to produce unsaturated nitrites by the vapor phase oxidation of an alkane, or a mixture of an alkane and an alkene, and ammonia in the presence thereof.

Abstract: Catalysts useful for producing methylamines and having practical catalyst life and large selectivity for dimethylamine comprise crystalline silicoaluminophosphate molecular sieves which have a molar ratio of silicon atom to aluminum atom in the range of 0.01-0.30.

Abstract: A gel composition substantially contained within the pores of a solid material for use as a catalyst or as a catalyst support in dehydrogenation and dehydrocyclization processes.

Abstract: A mixed metal oxide, which may be an orthorhombic phase material, is improved as a catalyst for the production of unsaturated carboxylic acids, or unsaturated nitrites, from alkanes, or mixtures of alkanes and alkenes, by: contacting with a liquid contact member selected from the group consisting of organic acids, alcohols, inorganic acids and hydrogen peroxide to form a contact mixture; recovering insoluble material from the contact mixture; calcining the recovered insoluble material in a non-oxidizing atmosphere; admixing the calcined recovered insoluble material with (i) at least one promoter element or compound thereof and (ii) at least one solvent for the at least one promoter element or compound thereof; removing the at least one solvent to form a catalyst precursor; and calcining the catalyst precursor.

Abstract: The present invention relates to a catalyst for producing methacrylic acid by the vapor-phase catalytic oxidation of methacrolein, comprising Mo, V, P and Cu as the indispensable active components, wherein copper acetate is used for all or a part of the necessary amount of a material for said Cu, a coated catalyst and a method for manufacturing the coated catalyst, and methacrolein is reacted in a high conversion and methacrylic acid is produced in a high selectivity by use of the catalyst of the present invention, and the catalyst can be used for reaction under high loading condition.

Abstract: A catalyst comprising a mixed metal oxide is useful for the vapor phase oxidation of an alkane or a mixture of an alkane and an alkene to an unsaturated carboxylic acid and for the vapor phase ammoxidation of an alkane or a mixture of an alkane and an alkene to an unsaturated nitrile.

Abstract: The present invention relates to a process for the selective preparation of acetic acid from a gaseous feed comprising ethane, ethylene or mixtures thereof plus oxygen at elevated temperature, which comprises bringing the gaseous feed into contact with a catalyst comprising the elements Mo, Pd, X and Y in gram atom ratios a:b:c:d in combination with oxygen MoaPdbXcYd??(I) where the symbols X and Y have the following meanings: X is one or more elements selected from the group consisting of: Cr, Mn, Nb, Ta, Ti, V, Te and/or W, in particular Nb, V and W; Y is one or more elements selected from the group consisting of: B, Al, Ga, In, Pt, Zn, Cd, Bi, Ce, Co, Cu, Rh, Ir, Au, Ag, Fe, Ru, Os, K, Rb, Cs, Mg, Ca, Sr, Ba, Zr, Hf, Ni, P, Pb, Sb, Si, Sn, TI and U, in particular Ca, Sb, Te and Li. The present invention further provides a catalyst for the selective preparation of acetic acid comprising the elements Mo, Pd, X and Y in the gram atom ratios a:b:c:d in combination with oxygen.