A method for producing diene comprises a step 1 of obtaining a straight chain internal olefin by removing a branched olefin from a raw material including at least the branched olefin and a straight chain olefin; and a step 2 of producing diene from the internal olefin by oxidative dehydrogenation using a first catalyst and a second catalyst, and the first catalyst has a complex oxide including bismuth, molybdenum and oxygen, and the second catalyst includes at least one selected from the group consisting of silica and alumina.

Oxidative dehydrogenation is an alternative to the energy extensive steam cracking process presently used for the production of olefins from paraffins, but has not been implemented commercially partially due to the unstable nature of hydrocarbon/oxygen mixtures, and partially due to the cost involved in the construction of new facilities. An oxidative dehydrogenation chemical complex designed to reduce costs by including integration of an oxygen separation module that also addresses safety concerns and reduces emission of greenhouse gases is described.

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.

Oxidative dehydrogenation is an alternative to the energy extensive steam cracking process presently used for the production of olefins from paraffins, but has not been implemented commercially partially due to the unstable nature of hydrocarbon/oxygen mixtures, and partially due to the cost involved in the construction of new facilities. An oxidative dehydrogenation chemical complex designed to reduce costs by including integration of an oxygen separation module that also addresses safety concerns and reduces emission of greenhouse gases is described.

The present invention relates to a catalyst for the dehydrogenation of hydrocarbons which is based on iron oxide and a process for producing it. The catalyst comprises at least one iron compound, at least one potassium compound and from 11 to 24% by weight of at least one cerium compound, calculated as CeO.sub.2, wherein the at least one iron compound and the at least one potassium compound are at least partly present in the form of one or more K/Fe mixed oxide phases of the general formula K.sub.xFe.sub.yO.sub.z, where x is from 1 to 17; y is from 1 to 22 and z is from 2 to 34, and comprises at least 50% by weight, based on the total catalyst, of the K/Fe mixed oxide phases, and also a process for producing it.

An object of the present invention is to provide a method for production of a high purity conjugated diolefin. The method for production of a conjugated diolefin of the present invention comprises steps of supplying a source gas containing a C4 or higher monoolefin and an oxygen-containing gas into a reactor, bringing a catalyst into contact with the gas mixture, compressing a gas containing a conjugated diolefin produced by an oxidative dehydrogenation reaction to obtain a liquefied gas and rinsing the liquefied gas with water.

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.

Disclosed is a method for producing, among others, alkenes and/or saturated or unsaturated oxygenates and, which include at least one of an aldehyde and an acid, comprising subjecting the corresponding C3 to C5 aliphatic alcohols that are derivable from biomass, to a vapor phase process over the catalytic system in the presence of a gas mixture of oxygen, air or nitrogen and/or other suitable diluting gas. The catalyst system comprises multi-catalytic zones, in each of which the composition of the co-feed and other reaction parameter can be independently controlled.

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.)

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.