A (methyl)acrolein oxidation catalyst and a preparation method therefor-in which the catalyst has a composition represented by the following formula: x(Mo12PaCsbVcDeOf)+tC/yZ in which Mo.sub.12P.sub.aC.sub.SbV.sub.cD.sub.eO.sub.f is a heteropolyacid salt main catalyst; C is a nano carbon fiber additive, and Z is a carrier thermal conduction diluent; Mo, P, Cs, V, and O represent the elements of molybdenum, phosphorus, cesium, vanadium, and oxygen, respectively; D represents at least one element selected from the group consisting of copper, iron, magnesium, manganese, antimony, zinc, tungsten, silicon, nickel, and palladium; a, b, c, e, and f represent the atomic ratio of each element, a=0.1-3, b=0.01-3, c=0.01-5, e=0.01-2, and f being the atomic ratio of oxygen required to satisfy the valence of each of the described components; x and y represent the weights of the main catalyst and the carrier thermal conduction diluent Z, and y/x=11.1-50%; and t represents the weight of the nano carbon fiber, and t/x=3-10%.

Provided is a catalyst precursor containing a Keggin-type heteropolyacid used for the production of an ,-unsaturated carboxylic acid by oxidation of an ,-unsaturated aldehyde.

Provided is a catalyst precursor containing a Keggin-type heteropolyacid used for the production of an ,-unsaturated carboxylic acid by oxidation of an ,-unsaturated aldehyde.

The invention relates to a method for catalytically producing formic acid and regenerating the catalyst used in the process. A vanadyl ion, vandate ion, or polyoxometallate ion, which is used as the catalyst, of the general formula [PMo.sub.xV.sub.yO.sub.40].sup.n is brought into contact with an alpha hydroxyl aldehyde, an alpha hydroxy carboxylic acid, a carbohydrate, a glycoside, or a polymer, which contains a carbon chain and which comprises at least one OH group that is bound to the carbon chain as a substituent in a repeating manner and/or an O, N, or S atom contained in the carbon chain in a repeating manner, in a liquid solution (12) in a vessel (10) at a temperature above 70 C. and below 160 C., wherein 6x11, 1y6, 3<n<10, and x+y=12, where n, x, and y is each a whole number. The catalyst reduced in the process is returned to its starting state by oxidation. For this purpose, the solution (12) is brought into contact with a gas (18) which contains a volume percent of oxygen of at least 18% at a pressure of at least 2 bar and maximally 16 bar by means of a mixing device or via a liquid-non-permeable gas-permeable membrane. CO and/or CO.sub.2 resulting during the reaction and merging with the gas (18) is discharged in such a quantity that the volume percent of CO and CO.sub.2 combined does not exceed 80% in the gas (18).

The invention relates to a method for catalytically producing formic acid and regenerating the catalyst used in the process. A vanadyl ion, vandate ion, or polyoxometallate ion, which is used as the catalyst, of the general formula [PMo.sub.xV.sub.yO.sub.40].sup.n is brought into contact with an alpha hydroxyl aldehyde, an alpha hydroxy carboxylic acid, a carbohydrate, a glycoside, or a polymer, which contains a carbon chain and which comprises at least one OH group that is bound to the carbon chain as a substituent in a repeating manner and/or an O, N, or S atom contained in the carbon chain in a repeating manner, in a liquid solution (12) in a vessel (10) at a temperature above 70 C. and below 160 C., wherein 6x11, 1y6, 3<n<10, and x+y=12, where n, x, and y is each a whole number. The catalyst reduced in the process is returned to its starting state by oxidation. For this purpose, the solution (12) is brought into contact with a gas (18) which contains a volume percent of oxygen of at least 18% at a pressure of at least 2 bar and maximally 16 bar by means of a mixing device or via a liquid-non-permeable gas-permeable membrane. CO and/or CO.sub.2 resulting during the reaction and merging with the gas (18) is discharged in such a quantity that the volume percent of CO and CO.sub.2 combined does not exceed 80% in the gas (18).

A catalyst and its use for selectively desulfurizing sulfur compounds present in an olefin-containing hydrocarbon feedstock to very low levels with minimal hydrogenation of olefins. The catalyst comprises an inorganic oxide substrate containing a nickel compound, a molybdenum compound and optionally a phosphorus compound, that is overlaid with a molybdenum compound and a cobalt compound. The catalyst is further characterized as having a bimodal pore size distribution with a large portion of its total pore volume contained in pores having a diameter less than 250 angstroms and in pores having a diameter greater than 1000 angstroms.

A catalyst and its use for selectively desulfurizing sulfur compounds present in an olefin-containing hydrocarbon feedstock to very low levels with minimal hydrogenation of olefins. The catalyst comprises an inorganic oxide substrate containing a nickel compound, a molybdenum compound and optionally a phosphorus compound, that is overlaid with a molybdenum compound and a cobalt compound. The catalyst is further characterized as having a bimodal pore size distribution with a large portion of its total pore volume contained in pores having a diameter less than 250 angstroms and in pores having a diameter greater than 1000 angstroms.

A catalyst comprising NiO, a metal mixture comprising at least one of MoO.sub.3 or WO.sub.3, a mixture comprising at least one of SiO.sub.2 and Al.sub.2O.sub.3, and P.sub.2O.sub.5. In this embodiment the metal sites on the catalyst are sulfided and the catalyst is capable of removing tar from a synthesis gas while performing methanation and water gas shift reactions at a temperature range from 300? C. to 600? C.

A catalyst comprising NiO, a metal mixture comprising at least one of MoO.sub.3 or WO.sub.3, a mixture comprising at least one of SiO.sub.2 and Al.sub.2O.sub.3, and P.sub.2O.sub.5. In this embodiment the metal sites on the catalyst are sulfided and the catalyst is capable of removing tar from a synthesis gas while performing methanation and water gas shift reactions at a temperature range from 300? C. to 600? C.

The present invention refers to catalysts that are selective for the reaction of ODH of propane to propene. Said catalysts are potassium salts of the dodecatungstophosphate ion partially substituted with vanadium and niobium, or mixed oxides of W, V, and Nb, with a tungsten bronze structure, obtained by thermal decomposition of polyoxometalate salts with a Keggin structure.