Multimetal oxide composition comprising Mo, Bi, Fe, Cu and one or more than one of the elements Co and Ni and use thereof.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

Provided are a method of preparing a multicomponent bismuth-molybdenum composite metal oxide catalyst, and a multicomponent bismuth-molybdenum composite metal oxide catalyst prepared thereby. According to the preparation method, since the almost same structure as that of a typical quaternary bismuth-molybdenum catalyst may be obtained by performing two-step co-precipitation, i.e., primary and secondary co-precipitation, of metal components constituting the catalyst, the reduction of catalytic activity due to the deformation of the structure of the catalyst may be suppressed. Also, since the multicomponent bismuth-molybdenum composite metal oxide catalyst may adjust the number of lattice oxygens consumed during a reaction to increase the catalytic activity, the multicomponent bismuth-molybdenum composite metal oxide catalyst may reduce the formation of by-products and may improve the conversion rate of reactant and the yield of desired product in a catalytic reaction process using the above catalyst, particularly, a catalytic reaction process under a relatively low temperature condition.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A method for producing an ammoxidation catalyst, the method including: a step (i) of preparing a starting material slurry comprising molybdenum, bismuth, iron, and a carboxylic acid compound; a step (ii) of stirring the starting material slurry in a temperature range of 30 to 50 C. for 20 minutes to 8 hours, thereby preparing a precursor slurry; a step of spray-drying the precursor slurry, thereby obtaining a dried particle; and a step of calcining the dried particle.

A metal oxide catalyst, which has a bulk composition represented by formula (1) below and which is used to produce a conjugated diolefin by an oxidative dehydrogenation reaction between a monoolefin, having 4 or more carbon atoms, and molecular oxygen, wherein standard deviation obtained by dividing a ratio of Bi molar concentration relative to Mo molar concentration at the surface of a catalyst particle by a ratio of the Bi molar concentration relative to the Mo molar concentration in a catalyst bulk is 0.3 or less.

Mo.sub.12Bi.sub.pFe.sub.qA.sub.aB.sub.bC.sub.cD.sub.dE.sub.eF.sub.fO.sub.x(1)

(In the formula, A is at least one type of element selected from the group consisting of Ni and Co, B is at least one type of element selected from among alkali metal elements, C is at least one type of element selected from the group consisting of Mg, Ca, Sr, Ba, Zn and Mn, D is at least one type of rare earth element, E is at least one type of element selected from the group consisting of Cr, In and Ga, F is at least one type of element selected from the group consisting of Si, Al, Ti and Zr, O is oxygen, p, q, a, b, c, d, e, f and x denote the number of atoms of Bi, Fe, A, B, C, D, E, F and oxygen, respectively, relative to 12 Mo atoms, and are such that 0.1p5, 0.5q8, 0a10, 0.02b2, 0c5, 0d5, 0e5 and 0f200, and x is the number of oxygen atoms required to satisfy valency requirement of other elements present.)

The present invention relates to a method for producing unsaturated aldehydes and unsaturated carboxylic acids. According to the present invention, a method for producing unsaturated aldehydes and unsaturated carboxylic acids which can impart activity and control temperature independently in fixed catalyst layer zones in a shell-and-tube reactor, thereby exhibiting improved yield and operation stability, is provided.

A method for producing an ammoxidation catalyst, comprising: a step of preparing a precursor slurry that is a precursor of the catalyst; a drying step of obtaining a dry particle from the precursor slurry; and a calcination step of calcining the dry particle, wherein the step of preparing the precursor slurry is a step of mixing a first solution or slurry having a first pH and a second solution or slurry to obtain a solution or slurry having a second pH after completion of mixing, a time during which a pH of a mixture passes through a particular range having an upper limit and a lower limit while the second solution or slurry is mixed is 1-70 seconds, he upper limit and the lower limit being designated as a third pH and a fourth pH respectively, and the third pH and the fourth pH are set between the first pH and the second pH.

A catalyst precursor represented by the following formula (1) having an average particle diameter (D50), which is a particle diameter at which a cumulative volume fraction is 50%, of 10 ?m or more and 40 ?m or less.

Mo.sub.a1Bi.sub.b1Ni.sub.c1Co.sub.d1Fe.sub.e1X.sub.f1Y.sub.g1Z.sub.h1O.sub.i1(1) where, Mo, Bi, Ni, Co and Fe represent molybdenum, bismuth, nickel, cobalt, and iron, respectively; X is tungsten or the like; Y is potassium or the like; and Z belongs to the 1st to 16th groups in the periodic table and represents at least one element selected from elements other than the above Mo, Bi, Ni, Co, Fe, X, and Y.

The present invention relates to a process for preparing molybdenum-bismuth-iron-cobalt-based multielement oxide catalysts by means of hydrothermal synthesis, wherein the hydrothermal synthesis is conducted with an aqueous solution and/or an aqueous suspension of precursor compounds of the elements present in the multielement oxide catalyst to be prepared, the pH of which has been adjusted to a value between about 6 and about 8. The present invention also further relates to the multielement oxide catalysts obtainable by this process and to the use thereof in the partial gas phase oxidation of olefins and tert-butanol.