JP2018043197A - Catalyst for manufacturing acrylic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst for manufacturing acrylic acid by a gas phase contact oxidation reaction of acrolein, excellent in long term stability and having high activity and a manufacturing method therefor, and a manufacturing method of acrylic acid using the catalyst.SOLUTION: There is provided a catalyst for manufacturing acrylic acid having diffraction peaks at 22.0°±0.3° and 26.5°±0.3° of a value of diffraction angle 2θ in an X ray diffraction pattern using Cu-Kα ray of a catalyst active component, a peak intention rate of maximum peak intensity in a range of 2θ=26.5°±0.3 R1 and maximum peak intensity in a range of 2θ=22.0°±0.3° R2, R1/R2 exhibiting 0.17 to 0.22, and containing molybdenum, vanadium, tungsten, copper and antimony in the catalyst active component.SELECTED DRAWING: Figure 1

Description

The present invention relates to a catalyst for producing acrylic acid in high yield by vapor phase catalytic oxidation of acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas, a method for producing the catalyst, and a method for producing acrylic acid using the catalyst. .

Acrylic acid is becoming increasingly important as a raw material for water-absorbing resins and adhesives. Therefore, in recent years, there has been a demand for improving the performance of a catalyst for producing acrylic acid by a gas phase catalytic oxidation reaction using acrolein as a raw material. Accordingly, each company has made various improvements regarding a catalyst that can stably produce acrylic acid in a high yield for a long period of time. For example, the following proposals have been made.

In Patent Document 1, in the 2θ value of X-ray diffraction using the Kα ray of copper as the catalytic active component (θ indicates the diffraction angle in X-ray diffraction), the peak intensity of 22.2 ° ± 0.3 ° is The largest molybdenum and vanadium oxide catalysts are disclosed.

In Patent Document 2, the diffraction angle 2θ = 22.2 ° ± 0.3 ° in the 2θ value of X-ray diffraction using the Kα ray of copper as the catalytic active component (θ indicates the diffraction angle in X-ray diffraction). Molybdenum and vanadium-based oxides with a ratio of the peak intensity of diffraction angle 2θ = 25.0 ° ± 0.3 ° (25.0 ° / 22.2 °) to the peak intensity of 0.1 to less than 0.7 A catalyst is disclosed.

In Patent Document 3, a peak at a diffraction angle 2θ = 28.3 ° (a1) in an X-ray diffraction 2θ value (θ indicates a diffraction angle in X-ray diffraction) using copper Kα ray as a catalytic active component. A molybdenum and vanadium-based oxide catalyst having a ratio of intensity and diffraction angle 2θ = peak intensity of about 27.6 ° (a2) (a1 / a2) of 0.1 or less is disclosed.

However, although these composite oxide catalysts currently exhibit performance as practical catalysts, further improvements in performance, particularly high activation, are required.

JP-A-8-299797 JP, 2015-120133, A JP 2003-251184 A

The present invention relates to a catalyst for producing acrylic acid by gas phase catalytic oxidation reaction of acrolein, a highly active catalyst for producing acrylic acid having excellent long-term stability, a method for producing the same, and acrylic acid using the catalyst. An object is to provide a manufacturing method.

As a result of intensive studies on a catalyst for producing acrylic acid in a high yield by gas phase catalytic oxidation reaction of acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas, the present inventors have determined that molybdenum, vanadium and antimony The value of the diffraction angle 2θ in the X-ray diffraction pattern using Cu—Kα ray of the catalytically active component contained has diffraction peaks at 22.0 ° ± 0.3 ° and 26.5 ° ± 0.3 °. The peak intensity ratio R1 / R2 between the maximum peak intensity R1 within the range of 26.5 ° ± 0.3 and the maximum peak intensity R2 within the range of 2θ = 22.0 ° ± 0.3 ° is 0.17. It has been found that a catalyst exhibiting 0.22 or less satisfies the above required performance.

That is, the present invention
(1) The diffraction angle 2θ has diffraction peaks at 22.0 ° ± 0.3 ° and 26.5 ° ± 0.3 ° in an X-ray diffraction pattern using Cu—Kα ray of the catalytically active component. The peak intensity ratio R1 / R2 between the maximum peak intensity R1 within the range of 2θ = 26.5 ° ± 0.3 and the maximum peak intensity R2 within the range of 2θ = 22.0 ° ± 0.3 ° is 0. A catalyst for producing acrylic acid that is not less than 17 and not more than 0.22;
(2) The catalytically active component is represented by formula (1)
_{Mo 12 V a W b Cu c} Sb d X e Y f Z g O h (1)
(In the formula, Mo, V, W, Cu, Sb and O respectively represent molybdenum, vanadium, tungsten, copper, antimony and oxygen, and X is at least one element selected from the group consisting of alkali metals and thallium. Y is at least one element selected from the group consisting of magnesium, calcium, strontium, barium and zinc, Z is niobium, cerium, tin, chromium, manganese, iron, cobalt, samarium, germanium, titanium and arsenic And at least one element selected from the group consisting of a, b, c, d, e, f, g, and h, each of which represents an atomic ratio of each element. a ≦ 10, b is 0 ≦ b ≦ 10, c is 0 <c ≦ 6, d is 0 <d ≦ 10, e is 0 ≦ e ≦ 0.5, f is 0 ≦ f ≦ 1, Represents 0 ≦ g <6, and h is the number of oxygen atoms necessary to satisfy the valence of each component.) The catalyst for producing acrylic acid according to (1) having a composition represented by: ,
(3) The catalyst for acrylic acid production according to (1) or (2), wherein the catalytically active component is supported on an inert carrier,
(4) The catalytically active component is represented by the formula (1)
_{Mo 12 V a W b Cu c} Sb d X e Y f Z g O h (1)
(In the formula, Mo, V, W, Cu, Sb and O respectively represent molybdenum, vanadium, tungsten, copper, antimony and oxygen, and X is at least one element selected from the group consisting of alkali metals and thallium. Y is at least one element selected from the group consisting of magnesium, calcium, strontium, barium and zinc, Z is niobium, cerium, tin, chromium, manganese, iron, cobalt, samarium, germanium, titanium and arsenic And at least one element selected from the group consisting of a, b, c, d, e, f, g, and h, each of which represents an atomic ratio of each element. a ≦ 10, b is 0 ≦ b ≦ 10, c is 0 <c ≦ 6, d is 0 <d ≦ 10, e is 0 ≦ e ≦ 0.5, f is 0 ≦ f ≦ 1, Represents 0 ≦ g <6, and h is the number of oxygen atoms necessary to satisfy the valence of each component.) The acrylic according to (2) or (3) A method for producing an acrylic acid production catalyst, which is an acid production catalyst comprising the following steps:
Step a) preparing a slurry solution or an aqueous solution (hereinafter referred to as A solution) containing at least molybdenum and vanadium as constituent elements,
Step b) Step of preparing a mixed solution of antimony-containing compound and basic aqueous solution (hereinafter referred to as “B solution”), Step c) Step of preparing a slurry liquid (hereinafter referred to as “C solution”) by mixing the above-mentioned A solution and B solution ,
Step d) A step of drying the liquid C obtained in the step c) and pre-baking the obtained catalytically active component solid A.
Step e) A step of molding the catalytically active component solid B after the preliminary calcination obtained in the step d),
Step f) A step of subjecting the molded body obtained in the step e) to main firing.
(5) Acrylic acid characterized by gas-phase catalytic oxidation of acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas using the catalyst according to any one of (1) to (3) Manufacturing method,
About.

The value of the diffraction angle 2θ in the X-ray diffraction pattern using Cu—Kα ray of the catalytically active component has diffraction peaks at 22.0 ° ± 0.3 ° and 26.5 ° ± 0.3 °, and 2θ = The peak intensity ratio R1 / R2 between the maximum peak intensity R1 within the range of 26.5 ° ± 0.3 and the maximum peak intensity R2 within the range of 2θ = 22.0 ° ± 0.3 ° is 0.17 or more. By using a catalyst exhibiting 0.22 or less, the reaction bath temperature can be suppressed, and acrylic acid can be produced in a high yield.

The result of the X-ray diffraction analysis of the catalytically active component of the catalyst of the present invention relating to Example 1 is shown. The result of the X-ray diffraction analysis of the catalytically active component of the comparative catalyst according to Comparative Example 1 is shown.

According to the present invention, the values of the diffraction angle 2θ in the X-ray diffraction pattern using Cu—Kα rays of the catalytically active components including molybdenum, vanadium and antimony are 22.0 ° ± 0.3 ° and 26.5 ° ± 0.00. It has a diffraction peak at 3 °, and a maximum peak intensity R1 within a range of 2θ = 26.5 ° ± 0.3 and a maximum peak intensity R2 within a range of 2θ = 22.0 ° ± 0.3 ° A catalyst for producing acrylic acid, characterized in that the peak intensity ratio R1 / R2 is 0.17 or more and 0.22 or less, can be provided.

The catalyst of the present invention is preferably a catalyst whose catalytic active component satisfies the following formula (1).
_{Mo 12 V a W b Cu c} Sb d X e Y f Z g O h (1)
(In the formula, Mo, V, W, Cu, Sb and O respectively represent molybdenum, vanadium, tungsten, copper, antimony and oxygen, and X is at least one element selected from the group consisting of alkali metals and thallium. Y is at least one element selected from the group consisting of magnesium, calcium, strontium, barium and zinc, Z is niobium, cerium, tin, chromium, manganese, iron, cobalt, samarium, germanium, titanium and arsenic And at least one element selected from the group consisting of a, b, c, d, e, f, g, and h, each of which represents an atomic ratio of each element. a ≦ 10, b is 0 ≦ b ≦ 10, c is 0 <c ≦ 6, d is 0 <d ≦ 10, e is 0 ≦ e ≦ 0.5, f is 0 ≦ f ≦ 1, Represents 0 ≦ g <6. Also, h is the number of oxygen atoms necessary for satisfying the valency of each component.).

The catalytically active component in the catalyst of the present invention is more preferably the formula (1), wherein a is 2 ≦ a ≦ 5, b is 0.2 ≦ b ≦ 2, c is 0.2 ≦ c ≦ 4, d is 0.3 ≦ d ≦ 4, e is 0 ≦ e ≦ 0.2, f is 0 ≦ f ≦ 0.5, and g is 0 ≦ g ≦ 3.

Molybdenum component raw materials constituting the catalytically active component represented by the above formula (1) include molybdenum oxides such as molybdenum trioxide, molybdic acid such as molybdic acid and ammonium molybdate or salts thereof, phosphomolybdic acid, silicium molybdenum. A heteropolyacid containing molybdenum such as an acid or a salt thereof can be used, but more preferably a high-performance catalyst tends to be obtained when ammonium molybdate is used. In particular, ammonium molybdate includes a plurality of types of compounds such as ammonium dimolybdate, ammonium tetramolybdate, and ammonium heptamolybdate. Among these, ammonium heptamolybdate is most preferable. Although there is no restriction | limiting in particular as an antimony component raw material, Antimony acetate is preferable. As raw materials for other elements such as vanadium, tungsten, copper, etc., it is usually possible to use oxides, nitrates, carbonates, organic acid salts, hydroxides, etc., which can be converted into oxides by heat, or mixtures thereof.

When the catalytically active component represented by the above formula (1) is supported on a carrier, a preferable catalyst can be provided. The type of carrier is not particularly limited, and specific examples that can be used include spherical carriers having a diameter of 2.5 mm to 10 mm, such as silicon carbide, alumina, mullite, alundum, and the like. Of these carriers, it is preferable to use a carrier having a porosity of 30% to 50% and a water absorption of 10% to 30%.

The catalyst of the present invention is preferably produced by the following production method.
Step a) preparing a slurry solution or an aqueous solution (hereinafter referred to as A solution) containing at least molybdenum and vanadium as constituent elements,
Step b) Step of preparing a mixed solution of antimony-containing compound and basic aqueous solution (hereinafter referred to as “B solution”), Step c) Step of preparing a slurry liquid (hereinafter referred to as “C solution”) by mixing the above-mentioned A solution and B solution ,
Step d) A step of drying the liquid C obtained in the step c) and pre-baking the obtained catalytically active component solid A.
Step e) A step of molding the catalytically active component solid B after the preliminary calcination obtained in the step d),
Step f) A step of subjecting the molded body obtained in the step e) to main firing.

In the step b), a mixed solution (solution B) of an antimony-containing compound and a basic aqueous solution is prepared. Although there is no restriction | limiting in particular as an antimony containing compound to be used, Antimony acetate is preferable. Moreover, there is no restriction | limiting in particular as basic aqueous solution to be used, However, Ammonia water is preferable.

In step c), liquid A and liquid B are mixed to prepare liquid C. In this step, the liquid B may be mixed after the preparation of the liquid A, or the liquid B may be added during the preparation of the liquid A.

The liquid C obtained in step d) is dried. The drying method is not particularly limited as long as the slurry solution can be completely dried, and examples thereof include drum drying, freeze drying, and spray drying. Among these, in the present invention, spray drying which can be dried from a slurry solution state to a powder state in a short time is preferable. The drying temperature in this case varies depending on the concentration of the slurry solution, the liquid feeding speed, etc., but the temperature at the outlet of the dryer is generally 85 ° C. or higher and 130 ° C. or lower.

Next, the dried powder obtained above is fired. Firing is preferably carried out in two stages: pre-firing performed before the molding step described below and main firing performed after molding. Pre-baking is possible by a known method and is not particularly limited. The pre-baking temperature in the present invention is usually 250 ° C. or higher and 500 ° C. or lower, preferably 300 ° C. or higher and 450 ° C. or lower, and the pre-baking time is usually 1 hour or longer and 15 hours or shorter, preferably 3 hours or longer and 6 hours or shorter. Such a pre-calcination step is effective in preventing powdered or exfoliated catalytically active components and filling a reaction tube with the finished catalyst, and obtaining a catalyst with low friability.

In step e), the pre-fired granules (hereinafter referred to as pre-fired granules unless otherwise specified) are formed. For molding, a powder obtained by pulverizing pre-fired granules with a ball mill or the like (hereinafter referred to as pre-fired powder unless otherwise specified) may be used. There is no particular limitation on the molding method. If necessary, pre-baked granules mixed with a binder are (A) a method of tableting molding, (B) mixing with molding aids such as silica gel, diatomaceous earth, and alumina powder and extruded into a spherical or ring shape. Examples of the molding method include (C) a method of carrying and carrying on a spherical carrier. In the present invention, the carrying catalyst of (C) is preferable.

Hereinafter, the supported catalyst which is a preferred embodiment of the catalyst of the present invention will be described in detail.
The supporting step is preferably the rolling granulation method described below. In this method, for example, in a device having a flat or uneven disk at the bottom of a fixed container, the support in the container is vigorously agitated by repeated rotation and revolution movements by rotating the disk at high speed. In this method, a binder, pre-fired granules, and, if necessary, a mixture of a molding aid and a strength improver are added to support the mixture on a carrier. The binder is (1) premixed in the mixture, (2) added at the same time as the mixture is added to the stationary container, (3) added after the mixture is added, (4) before adding the mixture. Addition, (5) A method of dividing the mixture and the binder, respectively, adding (2) to (4) as appropriate, and adding the total amount can be arbitrarily adopted. Of these, (5) is preferably carried out by adjusting the addition rate using an auto-feeder or the like so that the mixture does not adhere to the fixed container wall and the mixture does not aggregate, and a predetermined amount is supported on the carrier.

Specific examples of the carrier that can be used include a spherical carrier having a diameter of 2.5 mm to 10 mm, such as silicon carbide, alumina, mullite, and alundum. Of these carriers, it is preferable to use a carrier having a porosity of 30% to 50% and a water absorption of 10% to 30%. The ratio of the carrier to the supported powder is usually used in such an amount that the pre-fired powder / (pre-fired powder + carrier) = 10% by mass to 75% by mass, preferably 15% by mass to 50% by mass. . When the ratio of the supported powder is large, the reaction activity of the supported catalyst of the present invention increases, but the mechanical strength tends to decrease (the degree of wear increases). On the contrary, when the proportion of the supported powder is small, the mechanical strength is large (the degree of abrasion is small), but the reaction activity tends to be small.

In the present invention, a binder is preferably used when the pre-fired powder is supported on a carrier. Specific examples of the binder that can be used include water, ethanol, polyhydric alcohol, polyvinyl alcohol as a polymeric binder, celluloses such as crystalline cellulose, methylcellulose, and ethylcellulose, and an aqueous silica sol solution of an inorganic binder. Preferred are celluloses and diols such as ethylene glycol and triols such as glycerin, and particularly preferred are aqueous solutions of celluloses and glycerin having a concentration of 5% by mass or more. Among celluloses, crystalline cellulose is particularly preferable. By using appropriate amounts of celluloses and aqueous glycerin solution, the moldability is improved, and a highly active high performance catalyst with high mechanical strength can be obtained. The amount of these binders used is usually 2 parts by weight or more and 60 parts by weight or less based on 100 parts by weight of the pre-fired powder, but in the case of celluloses, it is preferably 2 parts by weight or more and 10 parts by weight or less, more preferably 3 parts by weight. Or more and 6 parts by mass or less, and in the case of an aqueous glycerin solution, they are 10 parts by mass or more and 30 parts by mass or less.

In the present invention, if necessary, molding aids such as silica gel, diatomaceous earth, and alumina powder may be used. The amount of the molding aid used is usually 5 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the pre-fired powder.

Further, if necessary, the use of inorganic fibers such as ceramic fibers and whiskers as a strength improving material is useful for improving the mechanical strength of the catalyst. However, fibers that react with catalyst components such as potassium titanate whiskers and basic magnesium carbonate whiskers are not preferred, and ceramic fibers are particularly preferred. The amount of these fibers used is usually 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the pre-fired powder. The molding aid and the strength improving material are usually mixed with a pre-fired powder. In this way, the pre-fired powder is supported on the carrier, and the supported product obtained at this time usually has a diameter of 3 mm to 15 mm.

In the above step f), the molded product obtained through the above step e) can be calcined to obtain the desired supported catalyst. In this case, the main baking temperature is usually 250 ° C. or higher and 500 ° C. or lower, preferably 300 ° C. or higher and 450 ° C. or lower, and the main baking time is 1 hour or longer and 50 hours or shorter. In addition, the main calcination in the case of adopting a molding method other than tableting and other support molding is usually performed under conditions of 250 to 500 ° C. for 1 to 50 hours.

The catalyst of the present invention thus obtained, particularly a supported catalyst, is preferably used in a process for producing an unsaturated acid using an unsaturated aldehyde as a raw material, but is preferably used for a process for producing acrylic acid using acrolein as a raw material. used.

The acrylic acid production catalyst of the present invention has a maximum peak intensity R1 in the range of 2θ = 26.5 ° ± 0.3, and a maximum peak intensity R2 in the range of 2θ = 22.0 ° ± 0.3 °. The peak intensity ratio R1 / R2 is 0.17 or more and 0.22 or less. A catalyst for producing acrylic acid having a value of R1 / R2 within this range has high activity and high selectivity.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Hereinafter, for convenience, “parts by mass” may be referred to as “parts”. The acrolein conversion, acrylic acid selectivity and acrylic acid yield in the examples and comparative examples were determined by the following formulas.
Acrolein conversion (mol%)
= (Mole number of reacted acrolein) / (Mole number of supplied acrolein) × 100
Acrylic acid selectivity (mol%)
= (Number of moles of acrylic acid produced) / (number of moles of reacted acrolein) × 100
Acrylic acid yield (mol%)
= (Number of moles of acrylic acid produced) / (number of moles of acrolein supplied) × 100

Measurement of X-Ray Diffraction of Catalyst X-ray powder diffraction spectra were measured using Cu-Kα radiation (X-ray output: 40 kV / 30 mA, Kα1-ray wavelength: 1.5406Å) using Ultimate IV manufactured by Rigaku Corporation. ).

Example 1
[Catalyst preparation]
To a preparation tank (X) equipped with a stirring motor, 520 parts of ion-exchanged water at 95 ° C. and 14.79 parts of ammonium tungstate were added and stirred. Next, 16.56 parts of ammonium metavanadate and 100 parts of ammonium molybdate were dissolved. Next, 7.05 parts of antimony acetate and 5.7 parts of 27.5 mass% ammonia water were put into a preparation tank (Y) containing 10 parts of ion-exchanged water at room temperature to obtain a mixed liquid (liquid B). The obtained mixed liquid was added to the preparation tank (X). Next, 14.29 parts of copper sulfate was dissolved in a preparation tank (Z) containing 42.7 parts of ion-exchanged water at 50 ° C., and the solution was added to the preparation tank (X) to obtain a slurry.
The amount of liquid fed was adjusted so that the outlet temperature of the spray dryer was about 110 ° C., and the resulting slurry was dried. The granules thus obtained were preheated at 350 ° C. for about 3 hours by raising the furnace temperature from room temperature at about 50 ° C. per hour. Next, this pre-fired granule was pulverized with a ball mill to obtain a pre-fired powder.
24.63 parts of the pre-fired powder obtained above and 1.23 parts of crystalline cellulose were uniformly mixed, and this mixture and 10 parts of a 20% by weight aqueous solution of glycerin were mixed using a tumbling granulator. It was made to carry, sprinkling on 50 parts of 4.9 mm alundum carriers. The obtained molded article was allowed to stand at room temperature for about 12 hours, and then placed in a furnace, the furnace temperature was raised from room temperature by about 50 ° C. per hour, and main calcination was performed at 390 ° C. for about 4 hours to obtain the catalyst of the present invention.
The element ratio of the active component excluding oxygen in the catalyst thus obtained was Mo ₁₂ V ₃ W _1.2 Cu _1.2 Sb _0.5
Met.
The result of the X-ray diffraction analysis of the catalytically active component of this catalyst is shown in FIG. The ratio R1 (26.6 °) / R2 (22.2 °) of the peak intensity at the diffraction angle 2θ = 26.6 ° to the peak intensity at the diffraction angle 2θ = 22.2 ° was 0.19.

[Oxidation reaction]
67.6 ml of the catalyst thus obtained was filled in a reaction tube having an inner diameter of 28.4 mm, and oxygen and nitrogen were added to the gas obtained by vapor-phase catalytic oxidation of propylene using a molybdenum-bismuth catalyst. A gas having the following composition was introduced, and the reaction was carried out at an SV (space velocity; the flow rate of the raw material gas per unit time / the apparent capacity of the filled catalyst) of 1032 / hr.
Acrolein 5.7 vol%
Unreacted propylene + other organic compounds 1.9 vol%
Oxygen 7.3 vol%
Steam 27.9 vol%
Nitrogen-containing inert gas 57.2 vol%
The reaction results were as follows. When the reaction bath temperature was 240 ° C., acrolein conversion = 95.7%, acrylic acid selectivity = 97.2%, and acrylic acid yield = 93.0%.

Comparative Example 1
[Catalyst preparation]
To a preparation tank (X) equipped with a stirring motor, 520 parts of ion-exchanged water at 95 ° C. and 14.79 parts of ammonium tungstate were added and stirred. Next, 16.56 parts of ammonium metavanadate and 100 parts of ammonium molybdate were dissolved. Next, 7.05 parts of antimony acetate was added to the mixing tank (X). 14.29 parts of copper sulfate was dissolved in a preparation tank (Y) containing 42.7 parts of ion-exchanged water at 50 ° C., and the solution was added to the preparation tank (X) to obtain a slurry liquid.
The amount of liquid fed was adjusted so that the outlet temperature of the spray dryer was about 110 ° C., and the resulting slurry was dried. The granules thus obtained were preheated at 350 ° C. for about 3 hours by raising the furnace temperature from room temperature at about 50 ° C. per hour. Next, this pre-fired granule was pulverized with a ball mill to obtain a pre-fired powder.
24.63 parts of the pre-fired powder obtained above and 1.23 parts of crystalline cellulose were uniformly mixed, and this mixture and 10 parts of a 20% by weight aqueous solution of glycerin were mixed using a tumbling granulator. It was made to carry, sprinkling on 50 parts of 4.9 mm alundum carriers. The obtained molded article was allowed to stand at room temperature for about 12 hours, and then placed in a furnace, the furnace temperature was raised from room temperature by about 50 ° C. per hour, and main calcination was performed at 390 ° C. for about 4 hours to obtain the catalyst of the present invention.
The element ratio of the active component excluding oxygen in the catalyst thus obtained was Mo ₁₂ V ₃ W _1.2 Cu _1.2 Sb _0.5
Met.
The result of the X-ray diffraction analysis of the catalytically active component of this catalyst is shown in FIG. The ratio R1 (26.6 °) / R2 (22.2 °) of the peak intensity at the diffraction angle 2θ = 26.6 ° to the peak intensity at the diffraction angle 2θ = 22.2 ° was 0.14.

[Oxidation reaction]
The catalyst thus obtained was reacted under the same conditions as in Example 1. As a result, when the reaction bath temperature was 240 ° C., acrolein conversion was 89.3% and acrylic acid selectivity was 96.7%. The acrylic acid yield was 86.4%.

Claims (5)

The value of the diffraction angle 2θ in the X-ray diffraction pattern using Cu—Kα ray of the catalytically active component has diffraction peaks at 22.0 ° ± 0.3 ° and 26.5 ° ± 0.3 °, and 2θ = The peak intensity ratio R1 / R2 between the maximum peak intensity R1 within the range of 26.5 ° ± 0.3 and the maximum peak intensity R2 within the range of 2θ = 22.0 ° ± 0.3 ° is 0.17 or more. A catalyst for producing acrylic acid that is 0.22 or less. The catalytically active component is formula (1)
_{Mo 12 V a W b Cu c} Sb d X e Y f Z g O h (1)
(In the formula, Mo, V, W, Cu, Sb and O respectively represent molybdenum, vanadium, tungsten, copper, antimony and oxygen, and X is at least one element selected from the group consisting of alkali metals and thallium. Y is at least one element selected from the group consisting of magnesium, calcium, strontium, barium and zinc, Z is niobium, cerium, tin, chromium, manganese, iron, cobalt, samarium, germanium, titanium and arsenic And at least one element selected from the group consisting of a, b, c, d, e, f, g, and h, each of which represents an atomic ratio of each element. a ≦ 10, b is 0 ≦ b ≦ 10, c is 0 <c ≦ 6, d is 0 <d ≦ 10, e is 0 ≦ e ≦ 0.5, f is 0 ≦ f ≦ 1, Represents 0 ≦ g <6, and h is the number of oxygen atoms necessary to satisfy the valence of each component). . The catalyst for acrylic acid production according to claim 1 or 2, wherein the catalytically active component is supported on an inert carrier. The catalytically active component is formula (1)
_{Mo 12 V a W b Cu c} Sb d X e Y f Z g O h (1)
(In the formula, Mo, V, W, Cu, Sb and O respectively represent molybdenum, vanadium, tungsten, copper, antimony and oxygen, and X is at least one element selected from the group consisting of alkali metals and thallium. Y is at least one element selected from the group consisting of magnesium, calcium, strontium, barium and zinc, Z is niobium, cerium, tin, chromium, manganese, iron, cobalt, samarium, germanium, titanium and arsenic And at least one element selected from the group consisting of a, b, c, d, e, f, g, and h, each of which represents an atomic ratio of each element. a ≦ 10, b is 0 ≦ b ≦ 10, c is 0 <c ≦ 6, d is 0 <d ≦ 10, e is 0 ≦ e ≦ 0.5, f is 0 ≦ f ≦ 1, Represents 0 ≦ g <6, and h represents the number of oxygen atoms necessary to satisfy the valence of each component). A method for producing an acrylic acid production catalyst, which is an acid production catalyst comprising the following steps:
Step a) preparing a slurry liquid or an aqueous dispersion (hereinafter referred to as Liquid A) containing at least molybdenum and vanadium as constituent elements,
Step b) Step of preparing a mixed solution of antimony-containing compound and basic aqueous solution (hereinafter referred to as “B solution”), Step c) Step of preparing a slurry liquid (hereinafter referred to as “C solution”) by mixing the above-mentioned A solution and B solution ,
Step d) A step of drying the liquid C obtained in the step c) and pre-baking the obtained catalytically active component solid A.
Step e) A step of molding the catalytically active component solid B after the preliminary calcination obtained in the step d),
Step f) A step of firing the molded body obtained in the step e). A method for producing acrylic acid, characterized in that acrolein is subjected to gas phase catalytic oxidation in the presence of molecular oxygen or a molecular oxygen-containing gas using the catalyst according to any one of claims 1 to 3. .

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