A catalyst containing, as an essential component, molybdenum; bismuth; and cobalt, in which a sum (S) of ratios of peak intensities expressed by the following formula in an X-ray diffraction pattern obtained by using CuKα rays as an X-ray source is 42 or more and 113 or less.

S={(peak intensity at 2θ=14.1°±0.1°+(peak intensity at 2θ=25.4°±0.1°)+(peak intensity at 2θ=28.5°±0.1°)}/(peak intensity at 2θ=26.5°±0.1°)×100

The present invention provides a method for producing 1,3-butadiene that is capable of suppressing generation of reaction by-products. The method includes: a step (A) of to obtain a produced gas containing 1,3-butadiene; a step (B) of cooling the produced gas; and a step (C) of separating the produced gas cooled in the step (B) into molecular oxygen and inert gases, and other gases containing 1,3-butadiene, by selective absorption into an absorption solvent. In the method, in the step (A), the raw material gas and a molecular oxygen-containing gas are supplied to a fixed-bed reactor with a composite oxide catalyst containing molybdenum and bismuth; the molar ratio of molecular oxygen to n-butene in the gases is 1.0 to 2.0; and the molar ratio of water vapor to n-butene in the gases supplied to the fixed-bed reactor is not more than 1.2.

A method of producing 1,3-butadiene including feeding oxygen and a feedstock gas containing n-butene into a reactor from the lower section of the reactor provided with a metal atom-containing catalyst, so that a product gas containing 1,3-butadiene is obtained through oxidative dehydrogenation of n-butene; cooling the product gas containing the 1,3-butadiene; and separating the 1,3-butadiene from the cooled product gas through selective absorption into an absorption solvent.

The present invention relates to a catalyst for oxidative dehydrogenation of butene and a method for producing the same. The catalyst for oxidative dehydrogenation of butene has a large amount of Mo—Bi phase acting as a reaction active phase on the surface, and therefore, can exhibit high catalytic activity, high conversion rate and high butadiene selectivity in the oxidative dehydrogenation of butene.

The invention is concerned with a method for producing a conjugated diene including a reaction step of subjecting a raw material gas containing a monoolefin having a carbon atom number of 4 or more to an oxidative dehydrogenation reaction with a gas containing molecular oxygen in the presence of a catalyst, to obtain a reaction product gas containing a conjugated diene; and a cooling step of cooling the reaction product gas, wherein in the cooling step, a cooling agent is supplied into a cooling column and brought into contact with the reaction product gas; the cooling agent discharged from the cooling column is then cooled by a heat exchanger; a precipitate dissolved in the cooling agent is precipitated within the heat exchanger and recovered; and the cooling agent from which the precipitate has been recovered is circulated into the cooling column.

Disclosed are a mesoporous composite oxide catalyst, a method for preparing the same and a method for synthesizing 1,3-butadidne using the same. The surface area is increased by introducing certain porous silica into preparation of a catalyst for synthesizing 1,3-butadiene, thereby improving a conversion ratio of normal-butene, and selectivity and yield of 1,3-butadiene, and providing economic efficiency from the viewpoint of decreasing an amount of used metal and reducing catalyst production cost.

Disclosed are a molybdenum based composite oxide catalyst, its preparation method and use. The catalyst has the following general formula: BiMo.sub.xM.sub.yN.sub.zO.sub.a; wherein M is one of V, Cr, Mn, Fe, Co, Ni and Cu, or a mixture of two or more of V, Cr, Mn, Fe, Co, Ni and Cu in any ratio; N is one of Na, K, Cs, Ca and Ba, or a mixture of two or more of Na, K, Cs, Ca and Ba in any ratio; x=0.5˜20; y=0.05˜20; z=0.01˜5; a is a number satisfying the valance of each atom. The catalyst is prepared by the following method: firstly mixing a certain amount of the lead metal oxides according to the chemical proportion and then grinding the mixture with high-energy ball milling for a period of time to obtain the molybdenum based composite oxide catalyst. The catalyst exhibits excellent performance when using for preparation of butadiene by oxidative dehydrogenation of butene, and the preparation process is simple, controllable, and repeatable. Waste water or waste gas that is difficult to be treated is not produced during preparation.

The invention relates to a process for preparing butadiene from n-butenes, comprising the steps of: A) providing an input gas stream a comprising n-butenes, B) feeding the input gas stream a comprising n-butenes and a gas containing at least oxygen into at least one oxidative dehydrogenation zone and oxidatively dehydrogenating n-butenes to butadiene, giving a product gas stream b comprising butadiene, unconverted n-butenes, water vapor, oxygen, low-boiling hydrocarbons and high-boiling secondary components, with or without carbon oxides and with or without inert gases; Ca) cooling the product gas stream b by contacting with a cooling medium in at least one cooling zone, the cooling medium being at least partly recycled and having an aqueous phase and an organic phase of an organic solvent, wherein the organic solvent is selected from the group consisting of toluene, o-, m- and p-xylene, mesitylene, mono-, di- and triethylbenzene, mono-, di- and triisopropylbenzene and mixtures thereof, and the mass ratio of the aqueous phase to the organic phase in the cooling medium when it is fed into the cooling zones prior to the contacting with the product gas stream being from 0.015:1 to 10:1, Cb) compressing the cooled product gas stream b which may have been depleted of high-boiling secondary components in at least one compression stage, giving at least one aqueous condensate stream c1 and one gas stream c2 comprising butadiene, n-butenes, water vapor, oxygen and low-boiling hydrocarbons, with or without carbon oxides and with or without inert gases; D) removing uncondensable and low-boiling gas constituents comprising oxygen and low-boiling hydrocarbons, with or without carbon oxides and with or without inert gases, as gas stream d2 from the gas stream c2 by absorbing the C.sub.4 hydrocarbons comprising butadiene and n-butenes in an absorbent, giving an absorbent stream laden with C.sub.4 hydrocarbons and the gas stream d2, and then desorbing the C.sub.4 hydrocarbons from the laden absorbent stream, giving a C.sub.4 product gas stream d1, E) separating the C.sub.4 product stream d1 by extractive distillation with a butadiene-selective solvent into a stream e1 comprising butadiene and the selective solvent and a stream e2 comprising n-butenes; F) distilling the stream e1 comprising butadiene and the selective solvent into a stream f1 consisting essentially of the selective solvent and a stream f2 comprising butadiene.

Disclosed is a multi-component bismuth molybdate catalyst for production of butadiene which comprises bismuth, molybdenum and at least one metal having a monovalent, divalent or trivalent cation, and further comprises cesium and potassium and thus has advantages of improving conversion ratio, yield and selectivity of butadiene and of providing stability of process operation.

A method for producing a conjugated diolefin is configured as follows. A monoolefin having four or more carbon atoms is fed from a plurality of monoolefin feed nozzles. In addition, at least 50% or more of a total amount of an oxygen-containing gas is fed from an oxygen-containing gas feed nozzle located at a bottom of a fluidized bed reactor. Furthermore, the plurality of monoolefin feed nozzles at n places located at heights a1, a2, . . . , and an from the oxygen-containing gas feed nozzle, respectively, feed the monoolefin having four or more carbon atoms at ratios of b1, b2, . . . , bn (b1+b2+ . . . +bn=1), respectively. Furthermore, a weighted mean value represented by the following formula is 100 mm or greater:
weighted mean value=a1*b1+a2*b2+ . . . +an*bn.