WO2005068072A1

WO2005068072A1 - Process for producing composite oxide catalyst

Info

Publication number: WO2005068072A1
Application number: PCT/JP2004/014221
Authority: WO
Inventors: Yoshimune Abe; Isao Teshigahara
Original assignee: Mitsubishi Chemical Corporation
Priority date: 2004-01-20
Filing date: 2004-09-29
Publication date: 2005-07-28
Also published as: CN1697692A; JP2005205263A

Abstract

A process for producing a composite oxide catalyst represented by the following general formula (I) which is for use in the vapor-phase catalytic oxidation of an unsaturated aldehyde with a gas containing molecular oxygen to produce the corresponding unsaturated fatty acid. The process is characterized by mixing an aqueous solution or dispersion containing raw-material compounds for part of a molybdenum ingredient and/or part of an X ingredient and for a copper ingredient with raw-material compounds for the remaining ingredients, i.e., molybdenum, vanadium, X, silicon, and carbon ingredients, either simultaneously or successively, drying the resultant mixture in an aqueous solution or dispersion state to prepare a powder, molding the powder, and burning the resultant molding. Mo12VaXbCucSidCeOf (I) [In the formula, X represents at least one element selected from the group consisting of niobium, tungsten, and antimony and a, b, c, d, e, and f, which indicate the atomic proportions of the respective elements, are as follows: 0<a≤12, 0<b≤12, 0<c≤12, 0≤d≤1,000, and 0≤e≤1,000 when the number of molybdenum atoms is 12, and f is a number determined by the degrees of oxidation of the components excluding silicon and carbon.]

Description

Specification

Method for producing composite oxide catalyst

Technical field

The present invention provides a composite oxide catalyst for producing a corresponding unsaturated carboxylic acid stably over a long period of time and in a high yield by subjecting an unsaturated aldehyde to gas-phase catalytic oxidation with a molecular oxygen-containing gas. And a method for producing the same.

Background art

[0002] Conventionally, various catalysts have been proposed for producing unsaturated carboxylic acids such as acrylic acid and methacrylic acid by subjecting unsaturated aldehydes such as acrolein and methacrolein to gas-phase catalytic oxidation with molecular oxygen. I have. From the viewpoint of effective use of unsaturated aldehyde raw materials produced by Olefinka and rationalization of the process in the reaction, these catalysts have a high conversion rate of unsaturated aldehydes and selectivity of unsaturated carboxylic acids as target products. Desired. In this case, for example, the reaction for producing acrylic acid with acrolein power is usually performed on a scale of 3 million tons Z years, so if the above conversion and selectivity improve even at 0.1%, the resulting product will Certain amounts of acrylic acid increase significantly at levels of hundreds and thousands of tons. Therefore, improvement in catalytic performance such as conversion and selectivity, even with a slight improvement, will contribute significantly to effective use of resources and rationalization of processes.

[0003] Conventionally, various proposals have been made with the aim of improving the catalyst performance such as the raw material conversion and selectivity of these reactions. The present applicant has also proposed, for example, Patent Document 1 and Patent Document 2 as composite oxide catalysts having excellent performance for that purpose. Patent Document 1 discloses that Mo Nb V Cu Si C X Y Z O (wherein, X is at least one selected from an alkali metal and T1.

2 a b c d e f g h i

Y represents at least one element selected from Mg, Ca, Sr, Ba and Zn, and Z represents W, Ce, Sn, Cr, Mn, Fe, Co, Y, Nd, Represents at least one element selected from Sm, Ge and 1. a, b, c, d, e, f, and g represent the atomic ratio of each element.For molybdenum atom 12, a is 0 <a≤12, 0 <b≤10, 0 <c≤8, 0 <d ≤ 1000, 0 <e ≤ 1000, 0 ≤ f ≤ 2, 0 ≤ g <5, 0 ≤ h <5, i is the oxidized component of each of the above components except Si and C A number of which depends on the degree). The

[0004] Further, Patent Document 2 discloses that Mo XYZ SiC O (wherein X represents Nb or Nb and V,

12 a b c d e f

Y represents at least one element selected from Cu and W, and Z represents at least one element selected from Sb and Fe. a, b, c, d, e, f, and g represent the atomic ratio of each element.For molybdenum atom 12, a is 0 <a≤12, 0 <b≤10, 0 <c≤8, 0 <d≤1000, 0 <e≤1000, and f is a number determined by the degree of oxidation of each component excluding Si and c among the above components). Things.

[0005] Further, Patent Document 3 is directed to an applicant separate from the present applicant, but as a catalyst used in the same reaction, X ⁷ Cu HO (where X ⁷ is Mo, W, V , Nb and / or Ta

12 h i y

, H is 4-30, i is 0-20, and y is a number determined by the degree of oxidation of each component), and the solid material is formed into Mo VX ¹ X ² X ³ X ⁴ X ⁵ X ⁶ O (where X ¹ is W, Ta, Cr and

12 a b c d e f g x

X or Z or Ce, X ² represents Cu, Ni, Co, Fe, Mn and Z or Zn, X ³ represents Sb and / or Bi, and X ⁴ represents Li, Na, Rb, Cs and / or Represents H, X ⁵ represents Mg, Ca, Sr and Z or Ba, X ⁶ represents Si, Al, Ti and Z or Zr, and y is a number determined by the degree of oxidation of each component. The present invention discloses a composite oxide catalyst obtained by drying and calcining a mixture added to an aqueous solution containing the component (a).

[0006] However, these conventional composite oxide catalysts exhibit excellent performances, respectively, but have higher performances. [1] Improvement of the raw material unsaturated aldehyde conversion and the unsaturated carboxylic acid selectivity. Is desired.

Patent Document 1: JP 2003-200055

Patent Document 2: Japanese Patent Application Laid-Open No. 2003-210991

Patent Document 3: International Publication WO9908788

Disclosure of the invention

Problems to be solved by the invention

[0007] The present invention provides a method for producing an unsaturated carboxylic acid by subjecting an unsaturated aldehyde to gas-phase catalytic oxidation with a molecular oxygen-containing gas to produce a high conversion of the raw material unsaturated aldehyde and a high unsaturated carboxylic acid. Provided is a method for producing a composite oxide catalyst which provides selectivity and exhibits stable performance over a long period of time. Means for solving the problem

[0008] The inventor of the present invention has made intensive studies to achieve the above object. As a result, Mo, V, X (Nb, W, and A complex oxide catalyst containing at least one element selected from the group consisting of Sb), Cu, Si, and C. When producing this catalyst, a part of the Mo component and the Z or X component An aqueous solution or dispersion of a part of each raw material compound of the Cu component is prepared separately from the remaining components of Mo, V, X, Si and C, and the aqueous solution or dispersion is prepared as Mo, V , X, Si and C are mixed simultaneously with the raw material compounds or the raw material compounds in an aqueous medium in an aqueous medium, and the resulting mixture is dried, molded, and calcined to obtain the catalyst. It has been found that the performance, particularly the selectivity of the unsaturated carboxylic acid as the target substance, is improved.

[0009] When only the specific component in the catalyst composition of the present invention is prepared in advance, and then mixed with the remaining component elements, the aqueous solution or water dispersion containing all the components of the catalyst composition is prepared. This is different from the usual method disclosed in Patent Literature 1 and Patent Literature 2. In addition, Patent Document 3 similarly prepares all target catalyst components in two parts, similarly to the present invention. However, unlike the present invention, one of the two parts is a preformed solid material. The components are mixed with the remaining catalyst component-containing liquid, and the components separately separated in advance are also disclosed in the present invention.

The present invention is characterized by the following points.

(1) Production of a complex oxide catalyst represented by the following formula (1), which is used in producing a corresponding unsaturated fatty acid by subjecting an unsaturated aldehyde to gas-phase catalytic oxidation with a molecular oxygen-containing gas. An aqueous solution or dispersion containing a part of the Mo component and a part of the Z or X component and each of the raw materials of the Cu component, and the remaining components Mo, V, X, and Si. And the raw material compounds of the components C and C are mixed in an aqueous medium with all the raw material compounds simultaneously or sequentially with each raw material compound, and the resulting mixture is dried to form an aqueous solution or dispersion to prepare a powder, A method for producing a composite oxide catalyst, comprising firing a molded product obtained by molding the powder.

[0011] Mo V X Cu Si C O (1)

12 a b c d e f

(Where Mo is molybdenum, V is vanadium, Cu is copper, Si is silicon, C is carbon, O is oxygen, and X is at least one of the group forces consisting of Nb, W, and Sb. Element A, b, c, d, e, and f indicate the atomic ratio of each element, and for molybdenum atom 12, 0 <a≤12, 0 <b≤12, 0 <c≤12, 0≤ d≤1000, 0≤e≤1000, f indicate the numbers determined by the degree of oxidation of each component excluding Si and C among the above components of equation (1))

(2) A method for producing corresponding acrylic acid by subjecting acrolein to gas-phase catalytic oxidation with a molecular oxygen-containing gas in the presence of the composite oxide catalyst according to (1).

The invention's effect

According to the present invention, when an unsaturated aldehyde is produced by gas phase catalytic oxidation of an unsaturated aldehyde with a molecular oxygen-containing gas to produce an unsaturated carboxylic acid! Accordingly, there is provided a method for producing a composite oxide catalyst which provides a high conversion rate of a raw material unsaturated aldehyde and a high selectivity of an unsaturated carboxylic acid, and shows stable performance over a long period of time.

[0013] In particular, the conversion rate of acrolein per catalyst unit is improved, the selectivity of acrylic acid for the catalyst is improved, and the high-V and complex oxidation activities for efficiently performing the gas phase catalytic oxidation reaction of acrolein are achieved. Product catalyst can be manufactured.

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] The composite oxidant catalyst produced by the present invention is represented by the above formula (1). In the general formula (1), X, a, b, c, d, e, and f are as described above. Among them, 0.1 ≤a≤6, 0. l≤b≤6, 0. l≤c≤6, 5≤d≤500, 5≤e≤500 force ^ Preferred! / ヽ.

[0015] The composite oxide catalyst according to the present invention comprises, among components constituting the catalyst composition represented by the general formula (1), a part of the Mo component and a part of the Z or X component, the Cu component, and the remaining component. It is manufactured by separately forming the components Mo, V, X, Si and C. That is, an aqueous solution or water dispersion containing a part of the Mo component, a part of the Z or X component, and a raw material compound of the Cu component is prepared in advance. In the aqueous solution or aqueous dispersion of the Mo component and a part of the Z or X component and the Cu component, the raw material compounds of the Mo component and the Z or X component and the Cu component are mixed, and the mixture is added to water. Or by mixing an aqueous solution or aqueous dispersion of the Mo component and the Z or X component-containing compound with an aqueous solution or aqueous dispersion of the Cu component-containing compound.

In the present invention, of the aqueous solution or the aqueous dispersion containing the Mo component and the Z or X component and the Cu component, the form of the aqueous solution is more preferable than the aqueous dispersion in view of the performance of the obtained catalyst. Mo This is presumably because the component and the Z or X component and the Cu component came into more close contact, and a uniform liquid was obtained.

In the present invention, the contents of the Mo component and the Z or X component and the Cu component in the aqueous solution or the aqueous dispersion are not particularly limited, but all components are preferably 5 to 50% by weight. Is selected, and a part of the Mo component and a part of the X component used here are preferably 5 to 50% by weight of the total Mo component contained in the catalyst composition in the case of the Mo component. In the case of X components, somewhat varies depending on the kind of component, 10 to 100 weight ^_0/0 of the total X component in the catalyst composition are preferred.

In the present invention, an aqueous solution or dispersion containing a part of the Mo component and a part of the Z or X component and the raw material mixture of the Cu component, and the remaining components of the catalyst composition, Mo, V The raw materials of the components X, Si and C are mixed in an aqueous medium. That is, the raw material compounds of the components Mo, V, X, Si, and C, which are the remaining components, are in the form of a solid, and a portion of the Mo component and a portion of the Z or X component and a Cu component. Can be added to and mixed with an aqueous solution or dispersion containing the raw material mixture of the above, or an aqueous solution or dispersion of these raw material compounds can be mixed with a part of the above Mo component and a part of the Z or X component. It can also be mixed in the form of an aqueous solution or dispersion containing the conjugate of the raw materials of the and the Cu component. The components of Mo, V, X, Si and C are prepared by simultaneously mixing all of the raw materials or successively each of the raw materials, a part of the Mo component and a part of the Z or X component. May be mixed with an aqueous solution or a dispersion containing the raw material compounds of Cu and the Cu component.

In the present invention, among the components constituting the catalyst composition, a part of the Mo component and a part of the Z or X component, the Cu component, and the remaining components Mo, V, X, Si and It is produced by separately forming the component C and the component C. Among them, the effect of the present invention is better when a part of the Mo component and the Nb component among the Z or X components are separately formed. Can be achieved. The aqueous solution or dispersion may contain a carrier material such as alumina, silica, and refractory oxide.

[0020] The raw material compound of each component of the composite oxide catalyst of the present invention is not particularly limited, as long as it is a water-soluble compound or a poorly water-soluble compound, as long as it is a compound that becomes an oxide upon firing. Specific examples of the raw material compound include halogenated compounds, sulfates, nitrates, ammonium salts, and acids of each component. Compounds, carboxylate, carboxylic acid ammonium salt, halogenated ammonium salt, hydrogen acid, acetyl acetonate, alkoxide and the like. Specific examples of the raw material compounds of silicon and carbon include green silicon carbide and black silicon carbide, and the silicon carbide is preferably in the form of fine powder. Specific examples of the silicon raw material conjugate include colloidal silica, powdered silica, granular silica, and the like. As the aluminum raw material conjugate, alumina and the like are used. As the raw material compound, a raw material compound containing each component alone or a raw material compound containing two or more components may be used.

[0021] As described above, an aqueous solution or dispersion containing a part of the Mo component and a part of the Z or X component and the raw material mixture of the Cu component, and the remaining components of the catalyst composition, Mo, By mixing the raw material compounds of the components V, X, Si and C, an aqueous solution or water dispersion containing all the catalyst components can be obtained. In many cases, a slurry is formed because some components do not dissolve. The amount of water in the aqueous solution or the aqueous dispersion is not particularly limited as long as the raw material compounds of the respective components can be completely dissolved or uniformly dispersed. What is necessary is just to determine suitably considering drying conditions, such as temperature and drying time. The amount of water is usually 100-2000 parts by weight based on 100 parts by weight of the raw material mixture. If the amount of water is less than the above-mentioned predetermined amount, the compound may not be completely dissolved or may not be mixed uniformly. In addition, if the amount of water is large, there is a fear that the energy cost during the heat treatment is increased. In many cases, the aqueous dispersion in the form of a slurry is preferably aged at room temperature—200 ° C. for 1 minute—24 hours.

Next, the aqueous solution or the aqueous dispersion is dried to form a powder. The drying is not particularly limited as long as the aqueous solution or the aqueous dispersion can be sufficiently dried and a powder can be obtained, and examples thereof include drum drying, freeze drying, and spray drying. Spray drying is a method that can be preferably applied to the present invention because it can be dried into a homogeneous powder state in a short time in an aqueous solution or aqueous dispersion.

[0023] The drying temperature varies depending on the concentration of the aqueous solution or aqueous dispersion and the like, but is usually 90 to 200 ° C, preferably 130 to 170 ° C. The powder obtained by vigorous drying preferably has a particle size of 10 to 200 m. For this reason, the powder can be optionally ground after drying. [0024] The powder obtained by the drying is molded as follows. The molding method is not particularly limited. Preferably, the molding is performed using a binder. Preferred binders are selected from silica, graphite and crystalline cellulose as well as group forces. The solder can be used in an amount of preferably about 110 to 50 parts by weight based on 100 parts by weight of the powder. In addition, if necessary, inorganic fibers such as ceramics fibers and whiskers can be used as a material for improving the mechanical strength of the catalyst particles. However, fibers that react with a catalyst component such as potassium titanate whiskers and basic magnesium carbonate whiskers are not preferred. Ceramic fibers are particularly preferred for improving strength. The amount of these fibers used is preferably 1 to 30 parts by weight based on 100 parts by weight of the powder. The above-mentioned molding aid is usually used by being previously mixed with a powder.

[0025] The molding of the powder mixed with a molding aid such as a binder may be carried out by a suitable method such as (A) tablet molding, (B) extrusion molding, (C) a sphere or other desired known shape supporting molding method. Can be adopted. An appropriate shape such as a spherical shape, a cylindrical shape, and a ring shape is preferably selected for the molded body. The molded product thus formed can be fired in the following to obtain a composite oxide catalyst. The firing temperature can be usually 250-500 ° C, preferably 300-420 ° C, and the firing time is 150 hours. The firing can be performed in an atmosphere in the presence of an inert gas or molecular oxygen. If the firing temperature is too low, the molybdenum element may be lost due to sublimation if the thermal diffusion of the element is too high. The molecular oxygen in the atmosphere gas is preferably 5% by volume or less. If the content of molecular oxygen exceeds 5% by volume, the activity of the catalyst may be insufficient. The content of molecular oxygen may be 0% by volume, but is preferably 0.05% by volume or more.

[0026] Means for producing a corresponding unsaturated carboxylic acid by using a catalyst produced according to the present invention and subjecting an unsaturated aldehyde to gas-phase oxidation using molecular oxygen or a gas containing molecular oxygen can be produced by a conventional method. It can be done by a method. For example, the reaction is carried out using a fixed-bed tube reactor. In this case, the reaction can be carried out under a condition generally used for this type of reaction, whether it is a single flow method or a recycling method through a reactor.

[0027] For example, mixing of acrolein with 11 to 15% by volume, molecular oxygen at 0.5 to 25% by volume, steam at 0 to 40% by volume, and inert gas such as nitrogen and carbon dioxide at 20 to 80% by volume. The gas is applied to the catalyst layer filled in each reaction zone of each reaction tube having an inner diameter of preferably 15-50 mm. Introduced at a space velocity (SV) of 300-5000hr- ¹ under pressure of IMPa at 50 ° C and 0.1-1. In the present invention, it is also possible to operate under a high load reaction condition, for example, under a higher raw material gas degree or a high space velocity in order to increase productivity. By virtue of the catalyst produced according to the present invention, acrylic acid can be produced with high selectivity and high yield. Example

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, it is needless to say that the present invention should not be construed as being limited to these Examples. The acrolein conversion, acrylic acid selectivity, and acrylic acid yield are defined by the following formulas.

Acrolein conversion ratio (mol%) = ιοο X (moles of reacted acrolein) Z (moles of supplied acrolein)

Acrylic acid selectivity (mol%) = 100 X (number of moles of acrylic acid generated) Z (number of moles of acrolein subjected to transfer)

Acrylic acid yield (mol ^_0/0) = 100 X (acrylic acid mol number generated) Z (Akurore Inmoru number of supplied)

Example 1

The composite metal oxide having a catalyst composition of Mo V W Nb Cu Si C excluding oxygen is as follows:

12 2.4 0.5 2 2 200 200

It was prepared as follows.

First, 88. Og of niobium ammonium oxalate was dissolved in 880 ml of pure water, and 47.6 g of copper sulfate was dissolved in 200 ml of pure water. The aqueous niobium ammonium oxalate solution and the aqueous copper sulfate solution were mixed to obtain a light blue aqueous dispersion. Separately, 937 ml of pure water was heated to 80 ° C, and 203 g of ammonium paramolybdate, 26.9 g of ammonium metavanadate, and 11.lg of ammonium methandastate were sequentially stirred. Upon dissolution, an aqueous solution was obtained. The aqueous dispersion containing niobium and copper was added to the aqueous solution and stirred to obtain a slurry liquid.

[0030] The slurry-like liquid is heated to 130 ° C and dried, and the obtained powder is formed into a column having a diameter of 6mm and a height of 4mm by a small tableting machine. At 380 ° C for 3 hours in a nitrogen stream to produce a catalyst.

[0031] In order to evaluate the obtained catalyst, 0.3 g obtained by crushing and sieving to 20-28 mesh, Placed in, Akurorein: filling the U-shaped reaction tube having an inner diameter of 4 mm, niter bath heated to the reaction tube (275 ° C temperature): 3.4 volume ^_0/0, oxygen: 9.3 volume ^_0/0, steam: 41.5 volume ^_0/0及beauty nitrogen gas: 45. introduced 8% by volume of the gas composition, SV; 14900Zhr (spatial velocity flow Z packed apparent volume of the catalyst of the raw material gas per unit time) — ^Reacted with ¹ .

[0032] The above-mentioned night game bath is a salt bath in which a reaction tube is placed in a heat medium composed of an alkali metal nitrate to cause a reaction. This heating medium melts at 200 ° C or higher, and can be used up to 400 ° C and has good heat removal efficiency, making it a reaction bath suitable for oxidation reactions with a large amount of heat generation.

As a result of the reaction, the acrolein conversion rate was 99.6%, the selectivity for acrylic acid was 98.1%, and the yield of atalylic acid was 97.7%.

Comparative Example 1

A composite metal oxide having a catalyst composition of Mo V W Nb Cu Si C excluding oxygen was prepared as follows.

12 2.4 0.5 2 2 200 200

Was prepared as follows.

First, 937 ml of pure water was heated to 80 ° C. to dissolve 203 g of ammonium paramolybdate, 26.9 g of ammonium metavanadate, and 11. lg of ammonium metatungstate. In this solution, an aqueous solution in which 88.Og of niobium oxalate was dissolved in 880 ml of pure water and an aqueous solution in which 47.6 g of copper sulfate were dissolved in 200 ml of pure water were dissolved or mixed while stirring sequentially. Add 782 g of silicon carbide powder to this solution and mix thoroughly.

[0034] The slurry-like liquid is heated to 130 ° C and dried, and the obtained powder is molded into a cylindrical shape having a diameter of 6mm and a height of 4mm by a small tableting machine. At 380 ° C for 3 hours in a nitrogen stream to produce a catalyst.

[0035] The reactivity of the obtained catalyst was evaluated under exactly the same conditions as in the examples. As a result of the reaction, the conversion of acrolein was 99.4%, the selectivity of acrylic acid was 97.8%, and the yield of acrylic acid was 97.2% when the temperature of the bath of the nita was 280 ° C.

[0036] As described above, a comparative example in which an aqueous dispersion formed by pre-mixing an aqueous niobium ammonium oxalate solution and a copper sulfate aqueous solution as a supply source of Nb and Cu is an acrylic resin. As a result, the yield was lower by 0.5% than that of the example in which the acid selectivity was low.

[0037] On the other hand, in an embodiment using an aqueous dispersion produced by premixing an aqueous niobium oxalate solution and an aqueous copper sulfate solution as a supply source of Nb and Cu, acrolein conversion was used. Rate, acrylic acid selectivity and acrylic acid yield were all excellent, and the gas phase catalytic oxidation reaction of acrolein could be performed efficiently.

Industrial applicability

The catalyst produced by the method of the present invention is used for producing a corresponding unsaturated carboxylic acid in a high yield by subjecting an unsaturated aldehyde to gas-phase catalytic oxidation with a molecular oxygen-containing gas. Manufactured unsaturated carboxylic acids such as acrylic acid are widely used as raw materials for various chemicals, monomers for general-purpose resins, monomers for functional resins such as water-absorbing resins, flocculants, and thickeners. Used for

Claims

The scope of the claims

[1] A composite oxidized product catalyst represented by the following general formula (1) used in producing an unsaturated fatty acid by subjecting an unsaturated aldehyde to gas-phase catalytic oxidation with a molecular oxygen-containing gas. An aqueous solution or dispersion containing a part of the Mo component and a part of the Z or X component and each of the starting materials of the Cu component, and the remaining components Mo, V, X, The raw material compounds of Si and the same component are mixed simultaneously in an aqueous medium with all the raw material compounds or sequentially with each raw material compound, and an aqueous solution or dispersion of the resulting mixture is dried to prepare a powder. A method for producing a composite oxide catalyst, comprising firing a molded product of a powder.

Mo V X Cu Si C O (1)

12 a b c d e f

(In the formula, X represents at least one element selected from the group force consisting of Nb, W, and Sb, a, b, c, d, e, and f represent the atomic ratio of each element, and the molybdenum atom In contrast to 12, a ≤ 12, 0 <b ≤ 12, 0 <c ≤ 12, 0 ≤ d ≤ 1000, 0 ≤ e ≤ 1000, and f are Si and The number is determined by the degree of oxidation of each component excluding C)

[2] A method for producing acrylic acid by subjecting acrolein to gas-phase catalytic oxidation with a molecular oxygen-containing gas in the presence of the composite oxide catalyst according to claim 1.