KR102228713B1 - Method for producing a catalyst for producing methacrylic acid, a method for producing methacrylic acid, and a method for producing methacrylic acid ester - Google Patents

Abstract

It provides a catalyst for producing methacrylic acid having a high methacrylic acid yield. (1) a step of preparing a catalyst raw material liquid A containing Mo, P, and V, (2) a step of preparing a catalyst raw material liquid B containing a cation raw material, and (3) a catalyst raw material liquid A and a catalyst raw material liquid A method for producing a catalyst for methacrylic acid production comprising a step of preparing a liquid containing a heteropoly acid having a Kegin-type structure or a salt thereof by adding and mixing the other liquid to any one of B, in step (3) A method of satisfying equations (i) and (ii).
3.0≤T/( ³ √V)≤13.0 (i)
0.01≤u1≤1.0 (ii)
(In formulas (i) and (ii), V is the volume of the catalyst raw material solution A [m ³ ], T is the number of addition ports to which the other liquid is added, and u1 is the volume flow rate of the other liquid to be added [L /Min] When T is 2 or more, u1 represents the average value.)

Description

Method for producing a catalyst for producing methacrylic acid, a method for producing methacrylic acid, and a method for producing methacrylic acid ester

The present invention relates to a method for producing a catalyst for producing methacrylic acid, a method for producing methacrylic acid, and a method for producing a methacrylic acid ester.

As a catalyst for producing methacrylic acid used in producing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen, a heteropolyacid-based catalyst containing molybdenum and phosphorus is known. As such a heteropolyacid-based catalyst, there are proton-type heteropolyacids in which the counter cation is a proton, and heteropolyacid salts in which a part of the proton is substituted with a cation other than a proton. As the heteropoly acid salt, an alkali metal salt in which the cation is an alkali metal ion and an ammonium salt in which the cation is an ammonium ion are known (hereinafter, the proton-type heteropolyacid is also simply referred to as ``heteropolyacid'', and at least one type selected from proton-type heteropolyacids and heteropolyacids It is also simply referred to as "heteropolyacid (salt)").

As a method for producing a catalyst for producing methacrylic acid, for example, in Patent Document 1, as a method for producing a catalyst for producing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen, (i) at least molyb The process of preparing a solution or slurry (liquid I) containing denum (Mo), phosphorus (P) and vanadium (V), (ii) preparing a solution or slurry (liquid II) containing ammonium root, and , (iii) Charge either liquid (PR liquid) of liquid I or liquid II to the tank (Group A), and 0.01 to 10 with respect to the total area of the face value of the PR liquid charged to the relevant group A. A step of preparing a liquid I liquid II liquid mixture by adding the other liquid (LA liquid) to a continuous liquid immunity area having an area of %, and (iv) a solution containing a catalyst precursor containing the entire catalyst component, or Disclosed is a method for producing a catalyst for producing methacrylic acid containing a predetermined atom in a predetermined atomic ratio, characterized by including a step of drying and firing a slurry.

International Publication No. 2005/039760

However, when the catalyst for methacrylic acid production produced by the method disclosed in Patent Document 1 is used for producing methacrylic acid, the yield of methacrylic acid is not sufficient, and further improvement is desired. In the present invention, an object of the present invention is to provide a catalyst for producing methacrylic acid having a high methacrylic acid yield.

The present invention is the following [1] to [18].

[1] As a method for producing a catalyst for producing methacrylic acid used in producing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen,

(1) a step of preparing a catalyst raw material solution A containing at least molybdenum, phosphorus and vanadium, and

(2) a step of preparing a catalyst raw material liquid B containing a cation raw material, and

(3) adding and mixing the other liquid to either one of the catalyst raw material liquid A and the catalyst raw material liquid B to prepare a liquid containing a heteropolyacid having a Keggin-type structure or a salt thereof,

In the step (3), a method for producing a catalyst for producing methacrylic acid satisfying the following formulas (i) and (ii).

3.0≤T/( ³ √V)≤13.0 (i)

0.01≤u1≤1.0 (ii)

(In formulas (i) and (ii), V is the volume of the catalyst raw material solution A [m ³ ], T is the number of addition ports for adding the other liquid, and u1 is the volume flow rate of the other liquid to be added. On the other hand, when T is 2 or more, u1 represents the average value of the volume flow rate of the other liquid added from each addition port.)

[2] As a method for producing a catalyst for producing methacrylic acid used in producing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen,

(1) a step of preparing a catalyst raw material solution A containing at least molybdenum, phosphorus and vanadium, and

(2) a step of preparing a catalyst raw material liquid B containing a cation raw material, and

(3) adding and mixing the catalyst raw material liquid B to the catalyst raw material liquid A to prepare a liquid containing a heteropolyacid having a Keggin-type structure or a salt thereof,

In the step (3), the method for producing a catalyst for producing methacrylic acid satisfying the following formulas (i) and (iii).

3.0≤T/( ³ √V)≤13.0 (i)

0.01≤u2≤8 (iii)

(In formulas (i) and (iii), V is the volume of the catalyst raw material liquid A [m ³ ], T is the number of addition ports for adding the catalyst raw material liquid B, and u2 is the cation raw material of the catalyst raw material liquid B. On the other hand, when T is 2 or more, u2 represents the average value of the flow rate of the cation raw material of the catalyst raw material liquid B added from each addition port.)

[3] In the above formula (i), the method for producing a catalyst for methacrylic acid production according to [1] or [2], wherein T is 2 or more.

[4] In the step (3), in [1], the other liquid is added and mixed in a container satisfying the following formula (iv) in which either of the catalyst raw material liquid A and the catalyst raw material liquid B is contained. Method for producing the catalyst for producing methacrylic acid described.

0.1≤S ³ /W ² ≤50 (iv)

(In formula (iv), S represents the surface area [m ² ] of the liquid level in the container, and W represents the volume of the liquid in the container [m ³ ].)

[5] In the step (3), the catalyst raw material liquid B is added and mixed in a container that satisfies the following formula (iv) in which the catalyst raw material liquid A is added, and the catalyst for producing methacrylic acid according to [2] is prepared. Way.

0.1≤S ³ /W ² ≤50 (iv)

(In formula (iv), S represents the surface area [m ² ] of the liquid level in the container, and W represents the volume of the liquid in the container [m ³ ].)

[6] The method for producing a catalyst for methacrylic acid production according to [4] or [5] in the step (3), wherein the addition port is disposed above the liquid level of the liquid in the container.

[7] In the step (3), the method for producing a catalyst for methacrylic acid production according to [6], which satisfies the following formula (v).

2≤T/S≤100 (v)

(In formula (v), T is synonymous with formula (i), and S is synonymous with formula (iv).)

[8] In the above step (3), from the center of the liquid level in the container, the center angle is 360°/T, and it is divided by a straight line of the T-bone drawn toward the wall surface of the container in approximately parallel to the liquid level. when the area of the liquid level by Y ₁ ~Y _T, respectively, the production method of the catalyst for producing methacrylic acid as set forth in [6] or [7], wherein the impregnated households that are arranged one on top of each Y ₁ ~Y _T .

[9] In the step (3), the addition port is centered on the center of the liquid level in the container, in the upper part of the circular area drawn by the radius R[m] calculated by the following formula (vi). The method for producing a catalyst for producing methacrylic acid according to any one of [6] to [8] which does not exist.

(In formula (vi), S is synonymous with the above formula (iv).)

[10] The method for producing a catalyst for methacrylic acid production according to [1], in which, in the step (3), the catalyst raw material liquid B is added and mixed in a container containing the catalyst raw material liquid A.

[11] The meta according to any one of [1] to [10], wherein the total volume of the catalyst raw material liquid A prepared in the step (1) and the catalyst raw material liquid B prepared in the step (2) is 0.2 m ^{3 or more.} Method for producing a catalyst for producing acrylic acid.

[12] The method for producing a catalyst for methacrylic acid production according to any one of [1] to [11], wherein the cation raw material is at least one selected from the group consisting of a compound containing an alkali metal and a compound containing an ammonium ion. .

[13] Further, of the catalyst for methacrylic acid production according to any one of [1] to [12], comprising the step of drying the liquid containing the heteropolyacid having a Keggin-type structure or a salt thereof to obtain a catalyst precursor. Manufacturing method.

[14] The method for producing a catalyst for methacrylic acid production according to [13], further comprising a step of heat-treating the catalyst precursor.

[15] The method for producing a catalyst for producing methacrylic acid according to any one of [1] to [14], wherein the catalyst for producing methacrylic acid has an elemental composition represented by the following formula (vii).

Mo _a P _b V _c Cu _d A _e E _f G _g O _h (vii)

(In formula (vii), Mo, P, V, Cu, and O are element symbols representing molybdenum, phosphorus, vanadium, copper, and oxygen, respectively. A is antimony, bismuth, arsenic, germanium, zirconium, and teller. Represents at least one element selected from the group consisting of rulium, silver, selenium, silicon, tungsten and boron E is iron, zinc, chromium, magnesium, calcium, strontium, tantalum, cobalt, nickel, manganese, barium , Titanium, tin, lead, niobium, indium, sulfur, palladium, gallium, cerium and lanthanum represent at least one element selected from the group consisting of G is lithium, sodium, potassium, rubidium, cesium and thallium Represents at least one element selected from the group consisting of: a, b, c, d, e, f, g and h represent the atomic ratio of each element, and when a=12, b=0.5 to 3, c =0.01 to 3, d=0.01 to 2, e=0 to 3, f=0 to 3, g=0.01 to 3, and h is the atomic ratio of oxygen required to satisfy the valency of each of the above elements.)

[16] A method for producing methacrylic acid in which methacrolein is gas-phase catalytically oxidized with molecular oxygen in the presence of a catalyst for producing methacrylic acid produced by the method according to any one of [1] to [15].

[17] A methacrylic acid production catalyst is prepared by the method according to any one of [1] to [15], and methacrolein is gas-phase catalytically oxidized with molecular oxygen in the presence of the methacrylic acid production catalyst. Method for producing acrylic acid.

[18] A method for producing a methacrylic acid ester in which methacrylic acid produced by the method for producing methacrylic acid according to [16] or [17] is esterified.

According to the present invention, it is possible to provide a catalyst for producing methacrylic acid having a high methacrylic acid yield.

[Method for producing catalyst for methacrylic acid production]

The method for producing a catalyst for producing methacrylic acid according to the present invention is a method for producing a catalyst for producing methacrylic acid used when producing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen. The first embodiment of the method includes the following steps (1) to (3).

(1) A step of preparing a catalyst raw material liquid A containing at least molybdenum, phosphorus and vanadium.

(2) A step of preparing a catalyst raw material liquid B containing a cation raw material.

(3) A step of adding and mixing the other liquid to either of the catalyst raw material liquid A and the catalyst raw material liquid B to prepare a liquid containing a heteropolyacid having a Keggin-type structure or a salt thereof.

In the step (3), the following formulas (i) and (ii) are satisfied.

3.0≤T/( ³ √V)≤13.0 (i)

0.01≤u1≤1.0 (ii)

In formulas (i) and (ii), V is the volume of the catalyst raw material solution A [m ³ ], T is the number of addition ports for adding the other liquid, and u1 is the volume flow rate of the other liquid added [ L/min]. On the other hand, when T is 2 or more, u1 represents the average value of the volume flow rate of the other liquid added from each addition port.

In addition, the second embodiment of the method includes the following steps (1) to (3).

(1) A step of preparing a catalyst raw material liquid A containing at least molybdenum, phosphorus and vanadium.

(2) A step of preparing a catalyst raw material liquid B containing a cation raw material.

(3) A step of adding and mixing the catalyst raw material liquid B to the catalyst raw material liquid A to prepare a liquid containing a heteropolyacid having a Keggin-type structure or a salt thereof.

In the step (3), the following formulas (i) and (iii) are satisfied.

3.0≤T/( ³ √V)≤13.0 (i)

0.01≤u2≤8 (iii)

In formulas (i) and (iii), V is the volume of the catalyst raw material solution A [m ³ ], T is the number of addition ports for adding the catalyst raw material solution B, and u2 is the cation raw material of the catalyst raw material solution B. It represents the flow rate [mol/min]. On the other hand, when T is 2 or more, u2 represents the average value of the flow rate of the cation raw material of the catalyst raw material liquid B added from each addition port.

In the first and second embodiments of the method according to the present invention, by including the steps (1) to (3) and satisfying the formulas (i) and (ii) in the step (3), Or, by satisfying the above (i) and (iii), a catalyst for producing methacrylic acid capable of producing methacrylic acid in a high yield can be prepared. The detailed mechanism is not necessarily disclosed, but it is assumed that catalyst particles effective in improving the methacrylic acid yield are easily produced.

The catalyst for methacrylic acid production prepared by the method according to the present invention includes at least molybdenum, phosphorus and vanadium, but may further include other elements such as copper in addition to these. From the viewpoint of being able to produce methacrylic acid in a high yield, the catalyst preferably has an elemental composition represented by the following formula (vii).

Mo _a P _b V _c Cu _d A _e E _f G _g O _h (vii)

In formula (vii), Mo, P, V, Cu, and O are element symbols representing molybdenum, phosphorus, vanadium, copper, and oxygen, respectively. A represents at least one element selected from the group consisting of antimony, bismuth, arsenic, germanium, zirconium, tellurium, silver, selenium, silicon, tungsten and boron. E is the group consisting of iron, zinc, chromium, magnesium, calcium, strontium, tantalum, cobalt, nickel, manganese, barium, titanium, tin, lead, niobium, indium, sulfur, palladium, gallium, cerium and lanthanum It represents at least one element selected from. G represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, cesium and thallium. a, b, c, d, e, f, g and h represent the atomic ratio of each element, and when a=12, b=0.5 to 3, c=0.01 to 3, d=0.01 to 2, e= 0-3, f=0-3, g=0.01-3, and h is the atomic ratio of oxygen required to satisfy the valence of each of the above elements. Meanwhile, the elemental composition is a value calculated by analyzing a component obtained by dissolving a catalyst in aqueous ammonia by an ICP emission analysis method.

(Step (1))

In step (1), a catalyst raw material liquid A containing at least molybdenum, phosphorus, and vanadium is prepared. For example, a catalyst raw material liquid A can be obtained by dissolving or suspending a raw material compound of a catalyst component containing molybdenum, phosphorus, and vanadium in a solvent using a preparation container. When the catalyst raw material liquid A contains at least molybdenum, phosphorus and vanadium, a catalyst for producing methacrylic acid having a higher methacrylic acid yield can be produced.

The raw material compound of the catalyst component is not particularly limited, and nitrate, carbonate, acetate, ammonium salt, oxide, halide, oxo acid, oxo acid salt, etc. of each constituent element of the catalyst can be used alone or in combination of two or more. I can. Examples of the raw material compound of molybdenum include molybdenum oxide such as molybdenum trioxide, ammonium paramolybdenum acid, and ammonium molybdenum acid such as ammonium dimolybdenum acid. Examples of the phosphorus raw material compound include phosphoric acid, phosphorus pentoxide, and ammonium phosphate. As a raw material compound of vanadium, ammonium metavanadate, vanadium pentoxide, vanadil oxalate, etc. are mentioned, for example. As a raw material compound of copper, copper nitrate, copper oxide, copper carbonate, copper acetate, etc. are mentioned, for example. The raw material compounds of the catalyst component may be used alone or in combination of two or more for each element constituting the catalyst component.

Examples of the solvent include water, ethyl alcohol, and acetone. These may use 1 type and may use 2 or more types together. Among these, it is preferable to use water.

The catalyst raw material liquid A is preferably prepared by adding a raw material compound of a catalyst component to a solvent using a preparation container, and stirring while heating. The heating temperature is preferably 80 to 130°C, and more preferably 90°C or more as the lower limit. Further, the pH of the catalyst raw material liquid A is preferably 3.0 or less, and more preferably 2.5 or less. As a method of making the pH of the catalyst raw material solution A to be 3.0 or less, for example, molybdenum trioxide is used as the molybdenum raw material, or a raw material compound of the catalyst component is selected so that a large amount of nitrate ions is contained. have. The concentration of the raw material compound of the catalyst component in the catalyst raw material liquid A is not particularly limited, but may be, for example, 5 to 90% by mass.

(Step (2))

In step (2), a catalyst raw material liquid B containing a cation raw material is prepared. For example, the catalyst raw material liquid B can be obtained by dissolving or suspending the cation raw material in a solvent using a preparation container.

Here, the term "cationic raw material" refers to a compound containing an alkali metal, a compound containing an alkaline earth metal, a compound containing a transition metal, a compound containing a non-metal, and a compound containing nitrogen (ammonia, ammonium At least one selected from the group consisting of an ion or a compound containing an alkylammonium ion, or a nitrogen-containing heterocyclic compound) is shown. Examples of the alkali metal include lithium, sodium, potassium, rubidium, and cesium. Examples of alkaline earth metals include magnesium, calcium, strontium, and barium. Examples of the compound containing an alkali metal, a compound containing an alkaline earth metal, a compound containing a transition metal, and a compound containing a non-metal include alkali metal, alkaline earth metal, transition metal or non-metal nitrate, carbonate, bicarbonate, acetate, Sulfates, ammonium salts, oxides, hydroxides, halides, oxo acids, oxo acid salts, and the like. As a compound containing an ammonium ion, ammonium bicarbonate, ammonium carbonate, ammonium nitrate, ammonium phosphate, ammonium vanadate, etc. are mentioned. Examples of the compound containing an alkyl ammonium ion include halides or hydroxides such as tetramethylammonium, tetraethylammonium, tetran-propylammonium, tetran-butylammonium, and triethylmethylammonium. Examples of the nitrogen-containing heterocyclic compound include pyridine, piperidine, piperazine, pyrimidine, quinoline, isoquinoline, and alkyl derivatives thereof. These may use 1 type and may use 2 or more types together. Among these, the cationic raw material is preferably at least one selected from the group consisting of a compound containing an alkali metal and a compound containing an ammonium ion from the viewpoint of obtaining a catalyst for producing methacrylic acid having a higher methacrylic acid yield.

Examples of the solvent include water, ethyl alcohol, and acetone. These may use 1 type and may use 2 or more types together. Among these, it is preferable to use water.

On the other hand, in the case of using a plurality of types as the cation raw material, by using a plurality of preparation containers and dissolving or suspending each cation raw material in a solvent, respectively, the catalyst raw material liquids B1, B2, ... In this way, a plurality of catalyst raw material liquids B may be prepared. When adding the catalyst raw material liquid B to the catalyst raw material liquid A, with respect to the catalyst raw material liquid A, the catalyst raw material liquids B1, B2, ... May be added in any order, or may be added at the same time. In the first embodiment, when the catalyst raw material liquid A is added to the catalyst raw material liquid B, the catalyst raw material liquid A may be added to any catalyst raw material liquid B, and the obtained liquid and the other catalyst raw material liquid B may be mixed. , And catalyst raw material solutions A1, A2, ... As described above, after dividing into a plurality of catalyst raw material liquids A and adding to the catalyst raw material liquid B, the obtained liquids may be mixed. In addition, the concentration of the cation raw material in the catalyst raw material liquid B is not particularly limited, but may be, for example, 5 to 90% by mass.

In addition, in the case of preparing the catalyst raw material liquids A and B in the steps (1) and (2), considering industrial production, from the viewpoint of production cost, the catalyst raw material liquid A prepared in the step (1) and volume of the total of the catalyst raw material solution B, prepared from the above-described step (2) is more preferably not less than, and preferably, less than 0.8m ³ to 0.2m ^3, more preferably at least 1.5m ^3. On the other hand, the upper limit of the range of the volume is not particularly limited, but ^{may be, for example, 5 m 3} or less.

(Step (3))

In the first embodiment, in step (3), the other liquid is added to and mixed with either of the catalyst raw material liquid A and the catalyst raw material liquid B to contain a heteropolyacid having a Keggin-type structure or a salt thereof. Prepare a liquid. That is, the catalyst raw material liquid B is added to the catalyst raw material liquid A and mixed, or the catalyst raw material liquid A is added to the catalyst raw material liquid B and mixed. In the former, the catalyst raw material liquid B and the latter, the catalyst raw material liquid A correspond to "the other liquid". Hereinafter, "the other liquid" is also shown as an additive liquid. Further, in the second embodiment, in step (3), the catalyst raw material liquid B is added to the catalyst raw material liquid A and mixed to prepare a liquid containing a heteropolyacid having a Keggin-type structure or a salt thereof. In the first embodiment, in the step (3), it is necessary to satisfy both the conditions of the following formulas (i) and (ii). In addition, in the second embodiment, in the step (3), it is necessary to satisfy both the conditions of the following formulas (i) and (iii).

3.0≤T/( ³ √V)≤13.0 (i)

0.01≤u1≤1.0 (ii)

0.01≤u2≤8 (iii)

In formulas (i), (ii) and (iii), V is the volume of the catalyst raw material solution A [m ³ ], T is the number of addition ports for adding the other liquid (the catalyst raw material solution B), u1 The volume flow rate [L/min] of the other liquid to which silver is added, u2 represents the flow rate [mol/min] of the cation raw material of the catalyst raw material liquid B. In addition, "addition tool" means the other liquid (catalyst raw material liquid B) installed to add the other liquid (catalyst raw material liquid B) to either of the catalyst raw material liquid A and the catalyst raw material liquid B (catalyst raw material liquid A). It is the exit of B). On the other hand, when T is 2 or more, u1 and u2 each represent the average value of the volume flow rate of the other liquid added from each addition port and the flow rate of the cation raw material of the catalyst raw material solution B added from each addition port. On the other hand, when there are a plurality of additive liquids, each needs to satisfy the above conditions. That is, catalyst raw material liquids B1, B2, ... as additive liquids. If there is, it is necessary that each addition of each liquid satisfies both conditions of equations (i) and (ii), or both conditions of equations (i) and (iii). In addition, in the first embodiment, catalyst raw material solutions A1, A2, ... Similarly, in the case where there is, it is necessary that each addition of each liquid satisfies both the conditions of formulas (i) and (ii).

By mixing the catalyst raw material liquid A and the catalyst raw material liquid B, a liquid containing a heteropolyacid (salt) having a Keggin type structure is obtained. In the above formula (i), T/( ³ √V) is the number of addition ports T divided by the cube root of the volume V of the catalyst raw material liquid A, and when mixing the catalyst raw material liquid A and the catalyst raw material liquid B, each It affects the contact state of the liquid. Thus, by a specific range of T / ⁽³ √V) In the formula (i), the heteropoly acid (salt) is assumed among jindago easily heteropolyacid (salt) is effective for improving the yield of methacrylic acid is produced. On the other hand, the total amount of the heteropolyacid (salt) obtained is related to the amount of the catalyst component contained in the catalyst raw material solution A. The value of T / ⁽³ √V) is satisfied 3.0≤T / ⁽³ √V) ≤13.0, the lower limit is at least 4.0 and preferably, 5.0 or more, and more preferred, more than 6.0 is more preferred. The upper limit is preferably 12.0 or less, more preferably 11.0 or less, and still more preferably 9.0 or less.

The value of T is preferably 2 or more, more preferably 4 or more, and still more preferably 8 or more from the viewpoint of obtaining a catalyst for methacrylic acid production with a higher methacrylic acid yield. The upper limit of the range of the value of T is not particularly limited, but may be, for example, 20 or less. As a method of making the value of T 2 or more, for example, a pipe having a plurality of holes or a plurality of nozzles having a plurality of discharge ports may be used. The diameter of the addition port is preferably 0.5 to 30 mm, the lower limit is more preferably 1 mm or more, and the upper limit is more preferably 10 mm or less.

In the above formula (ii), the volume flow rate u1 of the additive liquid affects the contact speed between the two liquids when the catalyst raw material liquid A and the catalyst raw material liquid B are mixed. Therefore, it is estimated that by adding the other liquid to either of the catalyst raw material liquid A and the catalyst raw material liquid B so as to satisfy the above formula (ii), catalyst particles effective in improving the methacrylic acid yield are likely to be generated. The value of u1 satisfies 0.01≦u1≦1.0, and the lower limit is preferably 0.05 or more, and more preferably 0.1 or more. The upper limit is preferably 0.5 or less, more preferably 0.4 or less, and still more preferably 0.3 or less.

In addition, in the above formula (iii), the flow rate u2 of the cation raw material of the catalyst raw material liquid B to be added affects the contact speed between the two liquids when the catalyst raw material liquid A and the catalyst raw material liquid B are mixed. Therefore, it is estimated that by adding the catalyst raw material liquid B to the catalyst raw material liquid A so as to satisfy the above formula (iii), catalyst particles effective in improving the methacrylic acid yield are easily produced. The value of u2 satisfies 0.01≦u2≦8, and the lower limit is preferably 0.1 or more, and more preferably 0.5 or more. As for the upper limit, 5 or less are preferable, 4 or less are more preferable, and 2 or less are still more preferable.

In the first embodiment, in the step (3), it is preferable to add and mix the other liquid in a container that satisfies the following formula (iv) in which either of the catalyst raw material liquid A and the catalyst raw material liquid B is contained. In addition, in the second embodiment, in the step (3), it is preferable to add and mix the catalyst raw material liquid B in a container that satisfies the following formula (iv) in which the catalyst raw material liquid A is contained.

0.1≤S ³ /W ² ≤50 (iv)

In formula (iv), S represents the surface area [m ² ] of the liquid level in the container, and W represents the volume of the liquid in the container [m ³ ]. Here, "liquid in a container" refers to the catalyst raw material liquid A or the catalyst raw material liquid B put in the container.

S ³ /W ² is a value related to the shape of a container in which the catalyst raw material liquid A and the catalyst raw material liquid B are mixed. By adjusting the shape of the container for mixing the catalyst raw material liquid A and the catalyst raw material liquid B so as to satisfy the above formula (iv), the surface area of the liquid surface relative to the volume of the liquid in the container becomes a desirable range, and a stable stirring state can be maintained. have. The ^{lower limit of the value of S 3} /W ² is more preferably 0.5 or more, and even more preferably 0.8 or more.

When the catalyst raw material liquid A and the catalyst raw material liquid B are each prepared using a preparation container in the steps (1) and (2), either of the catalyst raw material liquid A and the catalyst raw material liquid B (catalyst raw material liquid A ) As it is in the corresponding preparation container, and the other liquid (catalyst raw material liquid B) may be added, or in order to satisfy the above formula (iv), it may be transferred to a newly prepared container, and the additive liquid may be added. . Further, a plurality of containers may be used, and an additive liquid may be added to the liquid in the container so as to satisfy the formula (iv) in each container.

The value of S is not particularly limited, but 0.01 m ² ≤ ^{S ≤ 3} m 2 is preferable, the lower limit is 0.05 m ² or more, and the upper limit is 2 m ² or less. Further, the value of W is not particularly limited, 0.1m ³ ≤W≤4.5m ³ are preferred, the lower limit is more preferably more than 0.5m ^3, the upper limit is less than 3.0m ^3.

In the step (3), it is preferable that the addition port is disposed above the liquid level of the liquid in the container. In addition, it is preferable that the value of T/S satisfies the following formula (v).

2≤T/S≤100 (v)

In formula (v), T is the same as formula (i), and S is the same as formula (iv). T/S represents the number of addition ports per unit surface area of the liquid level in the container, and by adjusting so as to satisfy the above formula (v), a stable agitation state can be maintained. As for the value of T/S, 3 or more are more preferable and, as for the lower limit, 4 or more are still more preferable. As for the upper limit, 80 or less are more preferable, and 60 or less are still more preferable.

Also, from the center of the liquid level in the container, the area of the liquid surface divided by a straight line of the T-bone drawn toward the wall surface of the container substantially parallel to the liquid level so that the central angle is 360°/T is Y ₁ ∼ Y, respectively. _{When it is set as T} , it is more preferable that the said addition tool is arrange|positioned one by one each above each of Y _{1- Y T.} By arranging the addition port in this way, when the catalyst raw material liquid A and the catalyst raw material liquid B are mixed, the contact surface of both liquids becomes more even and the mixing state is stabilized, thereby stably producing catalyst particles effective for improving the methacrylic acid yield. can do. On the other hand, ``the center of the liquid level in the container'' refers to the center of the liquid level in the container, for example, when the shape of the liquid level is circular, the center of the circle, and when the shape of the liquid level is rectangular, it is the intersection of the diagonals. I can. In addition, "approximately parallel" means that it is parallel within the range of ±5 degrees. In particular, when the contact point of time from the addition port present in the Y ₁ upper got off the perpendicular to the liquid level within the liquid container to the Z _1, by 360 ° / T to the center of the liquid level within the liquid container in the axial Z ₁ It is preferable that all the addition openings are present in the upper part of the position in which the rotation is moved.

In the step (3), it is preferable that the addition port does not exist in the upper part of the circular area drawn by the radius R[m] calculated by the following formula (vi) with the center of the liquid level in the container as the center. Do. That is, it is preferable that the addition orifice is present in the upper portion outside the range of the circular region.

In formula (vi), S is synonymous with the above formula (iv). When the liquid level in the container is circular, in the following formula (vi), R is 1/3 of the radius of the liquid level in the container. By arranging the addition port in this way, when the catalyst raw material liquid A and the catalyst raw material liquid B are mixed, the contact surface of both liquids becomes more even and the mixed state is stabilized, thereby stably producing catalyst particles effective for improving the methacrylic acid yield. I can.

In addition, in the first embodiment, in the step (3), it is preferable to add and mix the catalyst raw material liquid B to a container containing the catalyst raw material liquid A. It is presumed that by mixing the catalyst raw material liquid containing the cation raw material as an additive liquid, catalyst particles effective in improving the methacrylic acid yield are more likely to be produced.

The liquid obtained in step (3) contains a heteropolyacid having a Keggin type structure or a salt thereof. When the liquid contains a heteropolyacid having a Keggin-type structure or a salt thereof, the resulting catalyst particles can be stably present without change, so that a catalyst having a high methacrylic acid yield can be obtained. On the other hand, that the liquid contains a heteropolyacid having a Keggin-type structure or a salt thereof can be confirmed by measuring the dried liquid by infrared absorption analysis. In the case of including a heteropolyacid having a Keggin-type structure or a salt thereof, the obtained infrared absorption spectrum has characteristic peaks around ^{1060, 960, 870, and 780 cm -1.}

The pH of the liquid obtained in step (3) is preferably 3.0 or less, and more preferably 2.5 or less. When the pH is 3.0 or less, a liquid containing a heteropolyacid having a Keggin-type structure or a salt thereof can be conveniently obtained. As a method of making this pH 3.0 or less, a method of adjusting the pH of the catalyst raw material liquid A to low in advance, etc. are mentioned.

(Drying process)

The method according to the present invention preferably includes a step of obtaining a catalyst precursor by drying the liquid containing the heteropolyacid having the Keggin-type structure or a salt thereof obtained in the step (3). Conditions such as a drying method or a drying temperature of the liquid are not particularly limited, and may be appropriately selected according to the shape or size of a desired dried product. Examples of the drying method include a drying method using a box dryer, a drum drying method, an airflow drying method, an evaporation drying method, and a spray drying method. The drying temperature can be, for example, 120 to 500°C, and the lower limit is preferably 140°C or more and the upper limit is 400°C or less. Drying can be carried out until the liquid is dry.

(Molding process)

In the method according to the present invention, before the heat treatment step described later, a step of shaping the catalyst precursor obtained in the drying step may be performed. The molding method is not particularly limited, and a known dry or wet molding method can be applied. For example, tablet molding, press molding, extrusion molding, granulation molding, etc. are mentioned. The shape of the molded article is not particularly limited, and examples thereof include a columnar shape, a ring shape, and a spherical shape. In addition, during molding, it is preferable to form the catalyst precursor alone without adding a carrier or a binder to the catalyst precursor, but if necessary, known additives such as graphite and talc, or known additives derived from organic or inorganic substances. You may add a binder. Hereinafter, the catalyst precursor obtained by the drying process and the molded article of the catalyst precursor obtained by the shaping process are collectively referred to as catalyst precursors.

(Heat treatment process)

The method according to the present invention preferably includes a step of heat-treating the catalyst precursor. For example, the catalyst precursor may be heat-treated in the flow of at least one of air and an inert gas. It is preferable that the heat treatment is carried out in the flow of an oxygen-containing gas such as air. In addition, "inert gas" indicates that it is a gas that does not decrease catalytic activity, and examples thereof include nitrogen, carbon dioxide gas, helium, argon, and the like. These may use 1 type, and may mix and use 2 or more types. The shape of the heat treatment container is not particularly limited, but it is preferable to use a tubular heat treatment container having a cross-sectional area of 2 square centimeters or more and 100 square centimeters or less. The heat treatment temperature is preferably 300°C or higher and 700°C or lower, more preferably 320°C or higher for the lower limit and 450°C or lower for the upper limit.

It is preferable that the catalyst for methacrylic acid production obtained in this way contains a heteropolyacid having a Keggin-type structure or a salt thereof, from the viewpoint of a higher methacrylic acid yield. The inclusion of a heteropolyacid having a Keggin-type structure or a salt thereof can be confirmed by measuring by infrared absorption analysis as described above.

[Method for producing methacrylic acid]

In the method for producing methacrylic acid according to the present invention, in the presence of a catalyst for producing methacrylic acid prepared by the method according to the present invention, methacrylic acid is produced by gas-phase catalytic oxidation of methacrolein with molecular oxygen. In addition, in the method for producing methacrylic acid according to the present invention, a catalyst for producing methacrylic acid is prepared by the method according to the present invention, and in the presence of the catalyst for producing methacrylic acid, methacrolein is gas-phase contacted with molecular oxygen. It is oxidized to produce methacrylic acid. According to these methods, methacrylic acid can be produced in high yield. Specifically, methacrylic acid can be produced by contacting a raw material gas containing methacrolein and molecular oxygen with a catalyst for producing methacrylic acid according to the present invention. This reaction can be carried out in a fixed bed. One catalyst layer may be sufficient, and two or more catalyst layers may be sufficient. The catalyst for methacrylic acid production may be supported on a support or may contain other additives. The concentration of methacrolein in the raw material gas is not particularly limited, but is preferably 1 to 20% by volume, the lower limit is more preferably 3% by volume or more, and the upper limit is more preferably 10% by volume or less. Methacrolein may contain a small amount of impurities that do not substantially affect the reaction, such as lower saturated aldehyde. The concentration of molecular oxygen in the raw material gas is preferably 0.4 to 4 moles per mole of methacrolein, more preferably 0.5 moles or more and 3 moles or less as the upper limit. On the other hand, as the molecular oxygen source, air is preferable from the viewpoint of economic efficiency, but if necessary, a gas obtained by adding pure oxygen to the air and enriching molecular oxygen may be used. The raw material gas may be one obtained by diluting methacrolein and molecular oxygen with an inert gas such as nitrogen or carbon dioxide gas. Additionally, water vapor may be added to the raw material gas. By performing the reaction in the presence of water vapor, methacrylic acid can be obtained in a higher yield. The concentration of water vapor in the raw material gas is preferably 0.1 to 50% by volume, the lower limit is more preferably 1% by volume or more, and the upper limit is more preferably 40% by volume or less. The contact time between the raw material gas and the catalyst for methacrylic acid production is preferably 1.5 to 15 seconds, the lower limit is more preferably 2 seconds or more and the upper limit is more preferably 5 seconds or less. The reaction pressure is preferably 0.1 MPa (G) to 1.0 MPa (G). On the other hand, (G) means that it is a gauge pressure. The reaction temperature is preferably 200 to 450°C, the lower limit is more preferably 250°C or more and the upper limit is 400°C or less.

[Method for producing methacrylic acid ester]

In the method for producing methacrylic acid ester according to the present invention, methacrylic acid prepared by the method according to the present invention is esterified. According to this method, methacrylic acid ester can be obtained using methacrylic acid obtained by gas phase catalytic oxidation of methacrolein. Examples of alcohols reacted with methacrylic acid include methanol, ethanol, isopropanol, n-butanol, and isobutanol. Examples of the obtained methacrylic acid ester include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. The reaction can be carried out in the presence of an acidic catalyst such as a sulfonic acid type cation exchange resin. The reaction temperature is preferably 50 to 200°C.

Example

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. "Parts" in Examples and Comparative Examples mean parts by mass. The molar ratio of the elemental composition of the catalyst was calculated by analyzing a component obtained by dissolving the catalyst in aqueous ammonia by ICP emission analysis. Analysis of the raw material gas and the product was performed using gas chromatography. From the results of gas chromatography, the conversion rate of methacrolein, the selectivity of methacrylic acid to be produced, and the single flow yield of methacrylic acid were determined by the following formula.

Metacrolein conversion rate (%) = (B/A) × 100

Methacrylic acid selectivity (%) = (C/B) × 100

Methacrylic acid single flow yield = (C / A) × 100

In the formula, A represents the number of carbon atoms of the supplied methacrolein, B represents the number of carbon atoms of the reacted methacrolein, and C represents the number of carbon atoms of the produced methacrylic acid.

In addition, u2 was calculated as the product of the molar concentration [mol/L] of the catalyst raw material liquid B and u1.

[Example 1]

100 parts of molybdenum trioxide, 7.5 parts of ammonium metavanadate, 11.4 parts of 85% by mass phosphoric acid aqueous solution, and 7.0 parts of copper(II) nitrate trihydrate were dissolved in 400 parts of pure water. The temperature was raised to 95°C while stirring, and the mixture was stirred for 2 hours while maintaining the liquid temperature at 95°C to obtain a catalyst raw material solution A. The pH of the catalyst raw material liquid A was 2.1. On the other hand, 15.7 parts of cesium bicarbonate was dissolved in 20 parts of pure water to obtain a catalyst raw material solution B1. Further, 20.0 parts of ammonium bicarbonate was dissolved in 20 parts of pure water to obtain a catalyst raw material solution B2. The total volume of the catalyst raw material liquid A, the catalyst raw material liquid B1, and the catalyst raw material liquid B2 was 2.1 m ³ .

While maintaining the liquid temperature of the catalyst raw material liquid A in the container at 95°C, the catalyst raw material liquid A was stirred using a rotary blade stirrer, while the catalyst raw material liquid B1 was added and stirred for 15 minutes. Then, catalyst raw material liquid B2 was added, and it stirred for 15 minutes. On the other hand, when adding catalyst raw material liquids B1 and B2, T=10, S=1.54m ² , V=1.9m ³ , S ³ /W ² =1.01, T/( ³ √V)=8.1, T/S =6.5, u1 = 0.20L/min. For u2 at this time, the catalyst raw material liquid B1 was 0.62 mol/min, and the catalyst raw material liquid B2 was 1.40 mol/minute. In addition, a ring-shaped pipe with a radius of 3×(√(S/π))/7[m] in which 2mm diameter addition holes are installed at equal intervals is located in the upper part of the center of the liquid level in the container. So, it was arrange|positioned so that each addition sphere may be arrange|positioned one by one above the area|regions Y _{1- Y 10.} Catalyst raw material liquids B1 and B2 were sequentially added from the addition port of the ring-shaped pipe. The resulting slurry contained a heteropolyacid having a Keggin-type structure or a salt thereof. Thereafter, the slurry was spray-dried to obtain a catalyst precursor.

The catalyst precursor was molded and placed in a sintering container made of cylindrical quartz glass having an inner diameter of 3 cm. A catalyst for methacrylic acid production was prepared by raising the temperature at 10°C/h under air flow and heat treatment at 380°C for 2 hours. The obtained catalyst for methacrylic acid production had a Keggin type structure. In addition, the element composition other than oxygen of the obtained catalyst for methacrylic acid production was Mo ₁₂ P _1.7 V _1.1 Cu _0.5 Cs _1.4 .

The catalyst for methacrylic acid production was charged into a reaction tube, and a raw material gas consisting of 5 vol% methacrolein, 10 vol% oxygen, 30 vol% steam and 55 vol% nitrogen was passed through, and the reaction was carried out at a reaction temperature of 300°C. . The product was collected and analyzed by gas chromatography to calculate the methacrylic acid yield. Table 1 shows the results.

[Example 2]

The total volume of the catalyst raw material liquid A, the catalyst raw material liquid B1, and the catalyst raw material liquid B2 is 0.10m ³ , T=4, S ^{=0.196m 2} , V=0.088m ³ , S ³ /W ² =0.97, T/( ³ Change to √V)=9.0, T/S=20.4, u1=0.03L/min, and add _{2mm diameter holes at equal intervals so that 1 addition} hole is placed at the top of the _{area Y 1 ∼ Y 4} A ring-shaped pipe having a radius of 3 × (√(S/π)) / 5 [m] installed was used. In addition, with respect to u2 at this time, the catalyst raw material liquid B1 was 0.09 mol/min, and the catalyst raw material liquid B2 was 0.21 mol/min. Except for these, a slurry was obtained by the same method as in Example 1. The resulting slurry contained a heteropolyacid having a Keggin-type structure or a salt thereof. After that, in the same manner as in Example 1, a catalyst for producing methacrylic acid was prepared. The obtained catalyst for methacrylic acid production had a Keggin type structure. In addition, the element composition other than oxygen of the obtained catalyst for methacrylic acid production was Mo ₁₂ P _1.7 V _1.1 Cu _0.5 Cs _1.4 . In addition, methacrylic acid was produced in the same manner as in Example 1, except that the catalyst for methacrylic acid production was used. Table 1 shows the results.

[Example 3]

T=13, S=1.54m ² , V=1.9m ³ , S ³ /W ² =1.01, T/( ³ √V)=10.5, T/S=8.4, u1=0.26L/min, In the region Y ₁ , all the addition ports were arranged above the region of a radius of 5×(√(S/π))/7 [m] or more from the center of the liquid level in the container. In addition, with respect to u2 at this time, the catalyst raw material liquid B1 was 0.80 mol/min, and the catalyst raw material liquid B2 was 1.83 mol/minute. Except for these, a slurry was obtained by the same method as in Example 1. The resulting slurry contained a heteropolyacid having a Keggin-type structure or a salt thereof. After that, in the same manner as in Example 1, a catalyst for producing methacrylic acid was prepared. The obtained catalyst for methacrylic acid production had a Keggin type structure. In addition, the element composition other than oxygen of the obtained catalyst for methacrylic acid production was Mo ₁₂ P _1.7 V _1.1 Cu _0.5 Cs _1.4 . In addition, methacrylic acid was produced in the same manner as in Example 1, except that the catalyst for methacrylic acid production was used. Table 1 shows the results.

[Comparative Example 1]

The total volume of the catalyst raw material liquid A, the catalyst raw material liquid B1, and the catalyst raw material liquid B2 is 0.0014m ³ , T=1, S=0.0177m ² , V=0.0013m ³ , S ³ /W ² =3.28, T/( ³ Change √V)=9.2, T/S=56.5, u1=1.41L/min, and the top of the position of 4×(√(S/π))/5[m] from the center of the liquid level in the container The addition sphere was placed on. In addition, with respect to u2 at this time, the catalyst raw material liquid B1 was 4.35 mol/min and the catalyst raw material liquid B2 was 9.90 mol/minute. Except for these, a slurry was obtained by the same method as in Example 1. The resulting slurry contained a heteropolyacid having a Keggin-type structure or a salt thereof. After that, in the same manner as in Example 1, a catalyst for producing methacrylic acid was prepared. The obtained catalyst for methacrylic acid production had a Keggin type structure. In addition, the element composition other than oxygen of the obtained catalyst for methacrylic acid production was Mo ₁₂ P _1.7 V _1.1 Cu _0.5 Cs _1.4 . In addition, methacrylic acid was produced in the same manner as in Example 1, except that the catalyst for methacrylic acid production was used. Table 1 shows the results.

[Comparative Example 2]

The total volume of the catalyst raw material liquid A, the catalyst raw material liquid B1, and the catalyst raw material liquid B2 is 0.00048m ³ , T=1, S=0.00785m ² , V=0.00043m ³ , S ³ /W ² =2.62, T/( ³ Change √V)=13.2, T/S=127.4, u1=0.07L/min, and the top of the position of 2×(√(S/π))/5[m] from the center of the liquid level in the container The addition sphere was placed on. In addition, with respect to u2 at this time, the catalyst raw material liquid B1 was 0.22 mol/min, and the catalyst raw material liquid B2 was 0.49 mol/minute. Except for these, a slurry was obtained by the same method as in Example 1. The resulting slurry contained a heteropolyacid having a Keggin-type structure or a salt thereof. After that, in the same manner as in Example 1, a catalyst for producing methacrylic acid was prepared. The obtained catalyst for methacrylic acid production had a Keggin type structure. In addition, the element composition other than oxygen of the obtained catalyst for methacrylic acid production was Mo ₁₂ P _1.7 V _1.1 Cu _0.5 Cs _1.4 . In addition, methacrylic acid was produced in the same manner as in Example 1, except that the catalyst for methacrylic acid production was used. Table 1 shows the results.

[Comparative Example 3]

100 parts of molybdenum trioxide, 7.5 parts of ammonium metavanadate, and 11.4 parts of an 85% by mass phosphoric acid aqueous solution were dissolved in 400 parts of pure water. The temperature was raised to 95°C while stirring, and the mixture was stirred for 2 hours while maintaining the liquid temperature at 95°C to prepare a catalyst raw material solution A. The pH of the catalyst raw material liquid A was 6.9. On the other hand, 15.8 parts of cesium nitrate was dissolved in 20 parts of pure water to prepare a catalyst raw material solution B1. Further, 40.0 parts of 30 mass% aqueous ammonia were dissolved in 20 parts of pure water to prepare a catalyst raw material solution B2. Further, 7.0 parts of copper (II) nitrate trihydrate was dissolved in 40 parts of pure water to prepare a catalyst raw material solution B3. The total volume of the catalyst raw material liquid A and the catalyst raw material liquids B1 to B3 was 2.3 m ³ .

The catalyst raw material liquid A was stirred using a rotary blade stirrer, while the liquid temperature of the catalyst raw material liquid A in the container was cooled to 50° C., while the catalyst raw material liquid B1 was added and stirred for 15 minutes. Then, catalyst raw material liquid B2 was added, and it stirred for 15 minutes. Furthermore, catalyst raw material liquid B3 was added. On the other hand, catalyst raw materials B1 to B3 were added in the same manner as in Example 3. In addition, with respect to u2 at this time, the catalyst raw material liquid B1 was 0.80 mol/minute, the catalyst raw material liquid B2 was 2.87 mol/minute, and the catalyst raw material liquid B3 was 0.18 mol/minute. The resulting slurry contained a heteropolyacid having a Dawson type structure or a salt thereof.

After that, in the same manner as in Example 1, a catalyst for producing methacrylic acid was prepared. The obtained catalyst for methacrylic acid production had a Dawson type structure. In addition, the element composition other than oxygen of the obtained catalyst for methacrylic acid production was Mo ₁₂ P _1.7 V _1.1 Cu _0.5 Cs _1.4 . In addition, methacrylic acid was produced in the same manner as in Example 1, except that the catalyst for methacrylic acid production was used. Table 1 shows the results.

[Comparative Example 4]

In the same manner as in Comparative Example 3, catalyst raw material liquids A and B1 to B3 were prepared. The catalyst raw material liquid A was stirred using a rotary blade stirrer, while the liquid temperature of the catalyst raw material liquid A in the container was cooled to 50° C., while the catalyst raw material liquid B1 was added and stirred for 15 minutes. Then, catalyst raw material liquid B2 was added, and it stirred for 15 minutes. Furthermore, catalyst raw material liquid B3 was added. On the other hand, catalyst raw materials B1 to B3 were added in the same manner as in Example 1. In addition, with respect to u2 at this time, the catalyst raw material liquid B1 was 0.62 mol/minute, the catalyst raw material liquid B2 was 2.21 mol/minute, and the catalyst raw material liquid B3 was 0.14 mol/minute. The resulting slurry contained a heteropolyacid having a Dawson type structure or a salt thereof.

After that, in the same manner as in Example 1, a catalyst for producing methacrylic acid was prepared. The obtained catalyst for methacrylic acid production had a Dawson type structure. In addition, the element composition other than oxygen of the obtained catalyst for methacrylic acid production was Mo ₁₂ P _1.7 V _1.1 Cu _0.5 Cs _1.4 . In addition, methacrylic acid was produced in the same manner as in Example 1, except that the catalyst for methacrylic acid production was used. Table 1 shows the results.

In Examples 1, 2 and 3, ^{the values of T/(3} √V) and values of u1 and u2 were within the range of the present invention, and it was confirmed that the catalyst was a high yield. On the other hand, in Example 3, the addition port was _{arranged only in the upper portion of the region Y 1} , and as compared with Examples 1 and 2, the yield was slightly lower than that of the catalyst. In addition, since the values of u1 and u2 of the catalyst raw material liquid B2 in Comparative Example 1 and the values of T/( ³ √V) in Comparative Example 2 were outside the range of the present invention, respectively, the yield was lower compared to the Example. In addition, in Comparative Examples 3 and 4, since the obtained slurry did not contain a heteropolyacid having a Keggin-type structure or a salt thereof, the yield was lower than in the examples. On the other hand, methacrylic acid ester can be obtained by esterifying the methacrylic acid obtained in this example.

This application claims the priority based on Japanese Patent Application No. 2016-161888 for which it applied on August 22, 2016, and uses all of the indication here.

As mentioned above, although this invention was demonstrated with reference to embodiment and an Example, this invention is not limited to the said embodiment and an Example. The configuration and details of the present invention can be made various changes that can be understood by those skilled in the art within the scope of the present invention.

The catalyst for methacrylic acid production obtained by the method according to the present invention is industrially useful because methacrylic acid can be produced in a high yield.

Claims (22)

As a method for producing a catalyst for producing methacrylic acid used when preparing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen,
(1) a step of preparing a catalyst raw material solution A containing at least molybdenum, phosphorus and vanadium, and
(2) a step of preparing a catalyst raw material liquid B containing a cation raw material, and
(3) adding and mixing the other liquid to either one of the catalyst raw material liquid A and the catalyst raw material liquid B to prepare a liquid containing a heteropolyacid having a Keggin-type structure or a salt thereof,
In the step (3), the following formulas (i) and (ii) are satisfied,
3.0≤T/( ³ √V)≤13.0 (i)
0.01≤u1≤0.5 (ii)
(In formulas (i) and (ii), V is the volume of the catalyst raw material solution A [m ³ ], T is the number of two or more addition ports for adding the other liquid, and u1 is the volume of the other liquid to be added. It represents the volume flow rate [L/min.] On the other hand, u1 represents the average value of the volume flow rate of the other liquid added from each addition port.)
The total volume of the catalyst raw material liquid A prepared in the step (1) and the catalyst raw material liquid B prepared in the step (2) is 0.2 m ³ or more,
In the step (3), the catalyst raw material liquid A and the catalyst raw material liquid B are added to a container that satisfies the following formula (iv), and the other liquid is added and mixed. Way.
0.1≤S ³ /W ² ≤50 (iv)
(In formula (iv), S represents the surface area [m ² ] of the liquid level in the container, and W represents the volume of the liquid in the container [m ³ ].) As a method for producing a catalyst for producing methacrylic acid used when preparing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen,
(1) a step of preparing a catalyst raw material solution A containing at least molybdenum, phosphorus and vanadium, and
(2) a step of preparing a catalyst raw material liquid B containing a cation raw material, and
(3) adding and mixing the catalyst raw material liquid B to the catalyst raw material liquid A to prepare a liquid containing a heteropolyacid having a Keggin-type structure or a salt thereof,
In the step (3), the following formulas (i) and (iii) are satisfied,
3.0≤T/( ³ √V)≤13.0 (i)
0.01≤u2≤5 (iii)
(In formulas (i) and (iii), V is the volume of the catalyst raw material liquid A [m ³ ], T is the number of two or more addition ports for adding the catalyst raw material liquid B, and u2 is the catalyst raw material liquid B It represents the flow rate [mol/min] of the cation raw material, while u2 represents the average value of the flow rate of the cation raw material of the catalyst raw material liquid B added from each addition port.)
The total volume of the catalyst raw material liquid A prepared in the step (1) and the catalyst raw material liquid B prepared in the step (2) is 0.2 m ³ or more,
In the step (3), the catalyst raw material liquid B is added and mixed in a container satisfying the following formula (iv) in which the catalyst raw material liquid A is added and mixed.
0.1≤S ³ /W ² ≤50 (iv)
(In formula (iv), S represents the surface area [m ² ] of the liquid level in the container, and W represents the volume of the liquid in the container [m ³ ].) The method of claim 1,
In the step (3), a method for producing a catalyst for producing methacrylic acid that satisfies the following formula (i-1).
4.0≤T/( ³ √V)≤12.0 (i-1) The method of claim 2,
In the step (3), a method for producing a catalyst for producing methacrylic acid that satisfies the following formula (i-1).
4.0≤T/( ³ √V)≤12.0 (i-1) The method of claim 1,
In the step (3), the catalyst raw material liquid A and the catalyst raw material liquid B are added to a container that satisfies the following formula (iv), and the other liquid is added and mixed. Way.
0.5≤S ³ /W ² ≤50 (iv)
(In formula (iv), S represents the surface area [m ² ] of the liquid level in the container, and W represents the volume of the liquid in the container [m ³ ].) The method of claim 2,
In the step (3), the catalyst raw material liquid B is added and mixed in a container satisfying the following formula (iv) in which the catalyst raw material liquid A is added and mixed.
0.5≤S ³ /W ² ≤50 (iv)
(In formula (iv), S represents the surface area [m ² ] of the liquid level in the container, and W represents the volume of the liquid in the container [m ³ ].) The method of claim 5,
In the step (3), the method for producing a catalyst for producing methacrylic acid, wherein the addition port is disposed above the liquid level of the liquid in the container. The method of claim 6,
In the step (3), the method for producing a catalyst for producing methacrylic acid, wherein the addition port is disposed above the liquid level of the liquid in the container. The method of claim 1,
In the step (3), the catalyst raw material liquid B is added to and mixed with a container containing the catalyst raw material liquid A. The method of claim 1,
In the step (3), a method for producing a catalyst for producing methacrylic acid that satisfies the following formula (ii-1).
0.05≤u1≤0.4 (ii-1) The method of claim 2,
In the step (3), a method for producing a catalyst for producing methacrylic acid that satisfies the following formula (iii-1).
0.1≤u2≤4 (iii-1) The method according to claim 7 or 8,
In the step (3), the method for producing a catalyst for producing methacrylic acid that satisfies the following formula (v).
2≤T/S≤100 (v)
(In formula (v), T is synonymous with formula (i), and S is synonymous with formula (iv).) The method according to claim 7 or 8,
In the process (3), from the center of the liquid level in the container, the center angle is 360°/T, in a straight line of the T-bone drawn toward the wall surface of the container in parallel within the range of ±5° to the liquid level. A method for producing a catalyst for producing methacrylic acid, wherein, when each of the regions of the liquid surface to be divided is Y _{1 to Y T} , the addition port _{is disposed one by one above each of Y 1 to Y T.} The method according to claim 7 or 8,
In the step (3), the addition port does not exist in the upper part of the circular area drawn by the radius R[m] calculated by the following formula (vi), centering on the center of the liquid level of the liquid in the container. Method for producing a catalyst for producing methacrylic acid.

(In formula (vi), S is synonymous with the above formula (iv).) The method according to any one of claims 1 to 11,
The method for producing a catalyst for producing methacrylic acid, wherein the cationic raw material is at least one selected from the group consisting of a compound containing an alkali metal and a compound containing an ammonium ion. The method according to any one of claims 1 to 11,
Further, a method for producing a catalyst for methacrylic acid production comprising a step of obtaining a catalyst precursor by drying the liquid containing the heteropoly acid having a Keggin-type structure or a salt thereof. The method of claim 16,
In addition, a method for producing a catalyst for producing methacrylic acid comprising the step of heat-treating the catalyst precursor. The method according to any one of claims 1 to 11,
The method for producing a catalyst for producing methacrylic acid, wherein the catalyst for producing methacrylic acid has an elemental composition represented by the following formula (vii).
Mo _a P _b V _c Cu _d A _e E _f G _g O _h (vii)
(In formula (vii), Mo, P, V, Cu, and O are element symbols representing molybdenum, phosphorus, vanadium, copper, and oxygen, respectively. A is antimony, bismuth, arsenic, germanium, zirconium, and teller. Represents at least one element selected from the group consisting of rulium, silver, selenium, silicon, tungsten and boron E is iron, zinc, chromium, magnesium, calcium, strontium, tantalum, cobalt, nickel, manganese, barium , Titanium, tin, lead, niobium, indium, sulfur, palladium, gallium, cerium and lanthanum represent at least one element selected from the group consisting of G is lithium, sodium, potassium, rubidium, cesium and thallium Represents at least one element selected from the group consisting of: a, b, c, d, e, f, g and h represent the atomic ratio of each element, and when a=12, b=0.5 to 3, c =0.01 to 3, d=0.01 to 2, e=0 to 3, f=0 to 3, g=0.01 to 3, and h is the atomic ratio of oxygen required to satisfy the valency of each of the above elements.) A method for producing methacrylic acid in which methacrolein is gas-phase catalytically oxidized with molecular oxygen in the presence of a catalyst for producing methacrylic acid produced by the method according to any one of claims 1 to 11. Methacrylic acid for producing a catalyst for methacrylic acid production by the method according to any one of claims 1 to 11, and catalytically oxidizing methacrolein with molecular oxygen in the presence of the catalyst for producing methacrylic acid. Manufacturing method. delete delete