KR20210097620A - Method for producing heteropoly acid compound, and method for producing heteropoly acid compound and methacrylic acid - Google Patents

Abstract

The present invention provides a method for producing a heteropolyacid compound. It is possible to produce a heteropolyacid compound which, when used as a catalyst in a gas-phase catalytic oxidation reaction, enables both excellent conversion rate and selectivity and enables a product to be obtained at a higher yield. A method for producing a heteropolyacid compound containing phosphorus, molybdenum, and copper comprises: a step (1) of obtaining aqueous slurry (C) by mixing an aqueous mixture (A) containing nitric acid and a phosphorus compound and an aqueous mixture (B) containing a molybdenum compound such that the amount of nitric acid is 1.2-2.0 moles per 12 moles of molybdenum; and a step (2) of obtaining aqueous slurry (E) by mixing the aqueous slurry (C) and an aqueous mixture (D) containing a copper compound so that the amount of copper is 0.01-0.20 mol per 12 mol of molybdenum.

Description

The manufacturing method of a heteropolyacid compound, the manufacturing method of a heteropolyacid compound, and methacrylic acid TECHNICAL FIELD

The present invention relates to a method for producing a heteropolyacid compound, a method for producing a heteropolyacid compound and methacrylic acid.

It is known that the heteropolyacid compound containing phosphorus and molybdenum can be widely used as a heterogeneous catalyst in various fields. For example, using a heteropolyacid compound as a catalyst at the time of gas-phase catalytic oxidation of methacrolein and manufacturing methacrylic acid is conventionally examined. In addition, when such a heteropolyacid compound is used as a catalyst, since the yield (conversion rate and selectivity) of the product obtained is greatly dependent on the performance of the heteropolyacid compound used, various manufacturing methods have been proposed with the aim of improving the performance of the catalyst. .

For example, in Unexamined-Japanese-Patent No. 2012-245432 (patent document 1), in the Example, the solution containing ion-exchange water, nitric acid, and orthophosphoric acid contains ion-exchange water and ammonium molybdate tetrahydrate. A method of further adding a suspension containing antimony trioxide, copper nitrate trihydrate, and ion-exchanged water to the suspension to be added dropwise while stirring and stirring to obtain a slurry, followed by drying and calcining the slurry is disclosed.

Japanese Laid-Open Patent Publication No. 2012-245432

Although the heteropolyacid compound obtained by the production method described in Patent Document 1 showed sufficiently high catalytic performance when used in the production method of methacrylic acid, a compound obtained in a higher yield also in the production method described in Patent Document 1 is obtained. There was room for improvement in this respect.

The present invention was made in view of the problems of the prior art, and when used as a catalyst in a gas phase catalytic oxidation reaction, both the conversion and selectivity can be made excellent, and it is possible to obtain a product with a higher yield An object of the present invention is to provide a method for producing a heteropolyacid compound capable of producing a heteropolyacid compound, a heteropolyacid compound obtained by the production method, and a method for producing methacrylic acid using the heteropolyacid compound.

MEANS TO SOLVE THE PROBLEM The present inventors repeat earnest research in order to achieve the said objective, As a result, the manufacturing method of the heteropolyacid compound containing phosphorus, molybdenum, and copper is made into a method comprising the following process (1) and the following process (2). When a heteropolyacid compound is used for the catalyst in a gas-phase catalytic oxidation reaction, both a conversion ratio and a selectivity can be made into the thing excellent, and it discovered that it became possible to achieve a higher yield, and it came to complete this invention.

That is, the manufacturing method of the heteropolyacid compound of this invention, the heteropolyacid compound, and the manufacturing method of methacrylic acid are as follows.

[1] A method for producing a heteropolyacid compound containing phosphorus, molybdenum, and copper, comprising the following steps (1) and (2):

[Step (1)] An aqueous slurry (C) is prepared by mixing (A) containing nitric acid and a phosphorus compound and an aqueous mixture (B) containing a molybdenum compound so that the nitric acid content is 1.2 to 2.0 moles with respect to 12 moles of molybdenum. obtaining process;

[Step (2)] A step of obtaining an aqueous slurry (E) by mixing the aqueous slurry (C) and an aqueous mixture (D) containing a copper compound so that the copper content is 0.01 to 0.20 mol with respect to 12 mol of molybdenum.

[2] In the step (2), the aqueous slurry (C) and the aqueous mixture (D) are mixed so that the copper content is 0.10 to 0.20 moles with respect to 12 moles of molybdenum, the heteropolyacid compound according to the above [1]. manufacturing method.

[3] A method for producing a heteropolyacid compound according to the above [1] or [2], further comprising the following step (3) and the following step (4):

[Step (3)] A step of drying the aqueous slurry (E);

[Step (4)] A step of calcining the dried product of the aqueous slurry (E) at 360°C to 410°C in an oxidizing gas atmosphere, and then calcining in a non-oxidizing gas atmosphere at 420°C to 500°C.

[4] The method for producing a heteropolyacid compound according to any one of [1] to [3], wherein the phosphorus compound is phosphoric acid.

[5] The method for producing a heteropolyacid compound according to any one of [1] to [4], wherein the aqueous mixture (A) further contains a nitrate.

[6] The method for producing a heteropolyacid compound according to any one of [1] to [5], wherein the molybdenum compound is a molybdate salt.

[7] The method for producing a heteropolyacid compound according to any one of [1] to [6], wherein the aqueous mixture (B) further contains a vanadium compound.

[8] The method for producing a heteropolyacid compound according to any one of [1] to [7], wherein the copper compound is a copper salt.

[9] The method for producing a heteropolyacid compound according to any one of [1] to [8], wherein the aqueous mixture (D) further contains an antimony compound.

[10] A heteropolyacid compound obtained by the method for producing a heteropolyacid compound according to any one of [1] to [9].

[11] The heteropolyacid compound has the following formula (I):

P _a Mo _b Cu _c V _d X _e Y _f O _x (I)

(In formula (I), P represents a phosphorus atom, Mo represents a molybdenum atom, Cu represents a copper atom, V represents a vanadium atom, O represents an oxygen atom,

X represents at least one atom selected from the group consisting of a potassium atom, a rubidium atom, a cesium atom and a thallium atom,

Y represents at least one atom selected from the group consisting of an arsenic atom, an antimony atom, a boron atom, a silver atom, a bismuth atom, an iron atom, a cobalt atom, a lanthanum atom, and a cerium atom,

a to f represent values satisfying the conditions of 1.2 ≤ a ≤ 1.8, 0.01 ≤ c ≤ 0.2, 0.4 ≤ d ≤ 0.6, 1.2 ≤ e ≤ 1.8, and 0.4 ≤ f ≤ 0.6 when b is 12 , x represents a value determined by the oxidation state of each atom. In addition, e and f represent the total ratio of 2 or more types of atoms when X and Y are 2 or more types of atoms, respectively.)

The heteropolyacid compound according to the above [10], which is a partially neutralized salt of a heteropolyacid represented by

[12] The heteropolyacid compound according to [10] or [11], wherein the BET specific surface area is 5 m 2 /g to 20 m 2 /g.

[13] In the presence of the heteropolyacid compound obtained by the method for producing a heteropolyacid compound according to any one of [1] to [9], or the heteropolyacid compound according to any one of [10] to [12], meta A method for producing methacrylic acid, comprising the step of subjecting at least one compound selected from the group consisting of crolein, isobutylaldehyde, isobutane and isobutyric acid to a gas phase catalytic oxidation reaction.

According to the present invention, when used as a catalyst in a gas phase catalytic oxidation reaction, both the conversion rate and the selectivity can be made excellent, and a heteropolyacid compound capable of producing a heteropolyacid compound capable of obtaining a product in a higher yield Production of a heteropolyacid compound It becomes possible to provide the method, the heteropolyacid compound obtained by the manufacturing method, and the manufacturing method of methacrylic acid using this heteropolyacid compound.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on the preferable embodiment.

[Method for Producing Heteropoly Acid Compound]

The manufacturing method of the heteropolyacid compound of this invention is a manufacturing method of the heteropolyacid compound containing phosphorus, molybdenum, and copper including the said process (1) and the said process (2). Hereinafter, each process is divided and demonstrated.

[Step (1)]

Step (1) is an aqueous slurry (C) by mixing an aqueous mixture (A) containing nitric acid and a phosphorus compound and an aqueous mixture (B) containing a molybdenum compound so that nitric acid is 1.2 to 2.0 moles with respect to 12 moles of molybdenum ) is the process of obtaining Hereinafter, first, the aqueous mixtures (A) and (B) used for a process (1) are demonstrated, and then, these mixing conditions etc. are demonstrated.

(with respect to the aqueous mixture (A))

Such an aqueous mixture (A) contains nitric acid and a phosphorus compound, and may contain water for preparing an aqueous mixture. The form is not particularly limited, and for example, contains nitric acid and a phosphorus compound. The aqueous solution to be used may be sufficient, or the aqueous slurry containing nitric acid and a phosphorus compound may be sufficient.

As a phosphorus compound contained in such an aqueous mixture (A), phosphoric acid (orthophosphoric acid), a phosphate, etc. can be used, Especially, phosphoric acid is more preferable. Moreover, as water used for preparation of such an aqueous mixture (A), ion-exchange water is preferable.

Moreover, it is preferable that such an aqueous|water-based mixture (A) contains nitrate further with nitric acid and a phosphorus compound. Examples of such nitrates include nitrates containing atoms other than a phosphorus atom, a molybdenum atom and a copper atom that can constitute a heteropolyacid compound, and nitrates other than these nitrates (such as ammonium nitrate). In addition, such a nitrate may be a nitrate containing atoms other than a phosphorus atom, a molybdenum atom and a copper atom, and is not particularly limited, but at least one selected from the group consisting of a potassium atom, a rubidium atom, a cesium atom and a thallium atom. a nitrate containing an atom of a species (hereinafter, simply referred to as "atom X" in some cases); At least one atom selected from the group consisting of an arsenic atom, an antimony atom, a boron atom, a silver atom, a bismuth atom, an iron atom, a cobalt atom, a lanthanum atom, and a cerium atom (hereinafter referred to as "atom Y" in some cases) nitrate containing; can be exemplified as a preferable thing (in addition, when a hydrate exists with respect to such a nitrate, you may use the hydrate). Further, as the nitrate to be contained in such an aqueous mixture (A), from the viewpoint of stability of the heteropoly acid salt, a nitrate containing the atom X (cesium nitrate, potassium nitrate, rubidium nitrate, thallium nitrate) is more preferable, and among them, Cesium nitrate is particularly preferred. By using such a nitrate containing atom X, it becomes possible to contain atom X in the heteropolyacid compound obtained, thereby making it possible to exhibit higher performance when used as a catalyst.

Moreover, the said aqueous mixture (A) may further contain other acids other than nitric acid and phosphoric acid. Examples of such other acids include inorganic acids such as hydrogen chloride, sulfuric acid, and nitrous acid; Organic acids, such as acetic acid and trifluoromethanesulfonic acid, are mentioned, Especially, an inorganic acid is preferable.

In addition, the method for preparing such an aqueous mixture (A) is not specifically limited, For example, mixing nitric acid, a phosphorus compound, and water (if necessary, another component with nitric acid, a phosphorus compound, and water) You may employ|adopt the method of preparing by adding and mixing (the said nitrate etc.). Moreover, it is preferable that the quantity of the water used at the time of preparation of such an aqueous mixture (A) is 30-90 mass % (more preferably 65-85 mass %) with respect to the aqueous mixture (A) obtained. In addition, when preparing the said aqueous mixture (A), the mixing order in particular of each component mentioned above, temperature, stirring conditions, etc. are not restrict|limited, What is necessary is just to set suitably. Further, when preparing such an aqueous mixture (A), from the viewpoint of dissolving the nitrate containing the atom X, nitric acid and a phosphorus compound are added to water heated to 20 to 90°C and mixed (if necessary, nitric acid and mixing) by adding another component together with the phosphorus compound. Moreover, even after the preparation, such an aqueous mixture (A) is maintained at the temperature (20-90 degreeC) heated at the time of preparation from a viewpoint of maintaining the nitrate containing atom X in the dissolved state, the process It is preferable to use for the mixing process of (1).

(with respect to the aqueous mixture (B))

The aqueous mixture (B) may contain a molybdenum compound and further contain water for an aqueous mixture, and the form is not particularly limited, for example, an aqueous solution containing a molybdenum compound may be used, The aqueous slurry containing a molybdenum compound may be sufficient. Moreover, as such water, ion-exchange water is preferable.

In addition, although it does not restrict|limit especially as a molybdenum compound contained in such an aqueous mixture (B), For example, tetramolybdate, chillimolybdate, palmolybdate, molybdenum trioxide, samolybdic acid, chillimolybdic acid, pal and molybdenum compounds such as molybdic acid, sunolybdate, imolybdate, trimolybdate, omolybdate, hexamolybdate, and molybdenum halide. may be used). As such a molybdenum compound, from the viewpoint of solubility, a molybdate is more preferable, and at least one selected from tetramolybdate, chimolybdate, palmolybdate, and hydrates thereof is still more preferable.

Examples of the tetramolybdate include diammonium tetramolybdate [(NH ₄ ) ₂ Mo ₄ O ₁₃ ], disodium tetramolybdate [Na ₂ Mo ₄ O ₁₃ ], dipotassium tetramolybdate [K ₂ Mo ₄ O ₁₃ ] can be mentioned.

Examples of the above-mentioned hexyl molybdate salt include ammonium chilmolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ ], sodium hexamyl molybdate [Na ₆ Mo ₇ O ₂₄ ], hexapotassium chillimolybdate [K ₆ Mo ₇ O ₂₄ ] can be mentioned.

Examples of the palmolybdate salt include tetraammonium palmolybdate [(NH ₄ ) ₄ Mo ₈ O ₂₆ ], tetrasodium palmolybdate [Na ₄ Mo ₈ O ₂₆ ], tetrapotassium palmolybdate [K ₄ Mo ₈ O ₂₆ ] can be mentioned.

Moreover, as such a molybdenum compound, it is preferable that it is an ammonium salt of a molybdic acid, and diammonium tetramolybdate, hexaammonium chilmolybdate, and tetraammonium palmolybdate are especially preferable.

It is preferable that the said aqueous mixture (B) further contains a vanadium compound other than a molybdenum compound. By further containing a vanadium compound in the said aqueous mixture (B), when it uses as a catalyst, it becomes possible to obtain the heteropolyacid compound which can exhibit more outstanding performance. Examples of such a vanadium compound include oxoacids, oxoates, oxides, nitrates, carbonates, bicarbonates, hydroxides, halides, and ammine complexes containing vanadium. More specifically, examples of such a vanadium compound include vanadates (metavanadates) such as vanadic acid and ammonium vanadate (ammonium metavanadate), vanadium oxide, and vanadium chloride. . Such a vanadium compound may use 2 or more types of them as needed. Moreover, as such a vanadium compound, from a viewpoint that the cation contained is an ammonium ion, ammonium vanadate (ammonium metavanadate) is more preferable.

_{Further, it is preferable not to contain nitrate ions (NO 3} ⁻ ) in the aqueous mixture (B), and even if nitrate ions are contained, the molar ratio of nitrate ions to 12 moles of molybdenum ([nitrate ions] /[Mo]) is preferably 0.01/12 or less. As such, it is preferable that the aqueous mixture (B) does not contain nitrate ions (the molar ratio of nitrate ions to 12 moles of molybdenum is 0/12). Therefore, it is preferable not to use nitric acid and the above-mentioned nitrate at the time of preparation of the said aqueous mixture (B).

In addition, the method for preparing such an aqueous mixture (B) is not specifically limited, For example, mixing a molybdenum compound and water (if necessary, with a molybdenum compound and water another component (the said vanadium compound) etc.) and mixing), you may employ|adopt the method of preparing by mixing). Moreover, as for the quantity of the water used at the time of preparation of such an aqueous mixture (B), 1-20 mass parts is preferable with respect to 1 mass part of molybdenum contained in the aqueous mixture (B) obtained. In addition, when preparing the said aqueous mixture (B), the mixing order in particular of each component mentioned above, temperature, stirring conditions, etc. are not restrict|limited, What is necessary is just to set suitably. Further, when preparing the aqueous mixture (B), from the viewpoint of dissolving the molybdenum compound, a molybdenum compound is added to water heated to 30 to 90° C. and mixed (if necessary, another component is added with the molybdenum compound It is preferable to add and mix). In addition, such an aqueous mixture (B) is maintained at the temperature (30-90 degreeC) heated at the time of preparation from a viewpoint of maintaining the state in which the molybdenum compound was dissolved even after the preparation, and using it for a mixing process desirable.

In addition, the said aqueous mixture (A) and the said aqueous mixture (B) may contain other components other than the compound mentioned above, respectively. Such other components are not particularly limited, and, according to the design of the target heteropolyacid compound, any known component usable for the preparation of the heteropolyacid compound can be appropriately used, and among them, other than a phosphorus atom, a molybdenum atom and a copper atom Compounds containing other atoms of In addition, such other atoms are not particularly limited as long as they can be contained as constituent atoms of the heteropolyacid compound, and preferred examples include the atom X, the atom Y, and vanadium. Moreover, as a compound containing other atoms contained in such an aqueous mixture (A) and the said aqueous mixture (B), it is a component which is not contained in one aqueous mixture, and contains in the aqueous mixture (D) mentioned later. It is preferable to select and use ingredients that have not been made. For example, when a vanadium compound is contained in the aqueous mixture (B), a compound other than the vanadium compound is selected as the compound to be contained in the aqueous mixture (A), depending on the component contained in the other aqueous mixture, etc. It is preferable to select and use the component to be used suitably.

Moreover, as a compound (compounds other than the above-mentioned nitrate) containing these other atoms, for example, oxo acid, oxo acid salt, oxide, nitrate, carbonate, bicarbonate, hydroxide, halide, and ammine complexes. Moreover, when a hydrate exists in such a compound, the hydrate can be used. As such a compound, the compound containing the atom X, the compound containing the atom Y, and a vanadium compound are preferable.

Moreover, from a viewpoint of making it contain in the said aqueous mixture (A), the compound containing the atom X is more preferable among these compounds. Moreover, as such an atom X, cesium is preferable. Moreover, as a compound containing the said atom X, Oxides, such as potassium oxide, a rubidium oxide, and a cesium oxide, other than the nitrate mentioned above; carbonates such as potassium carbonate, rubidium carbonate, and cesium carbonate; Bicarbonates, such as potassium hydrogencarbonate and cesium hydrogencarbonate; hydroxides such as potassium hydroxide, rubidium hydroxide, and cesium hydroxide; and halides such as potassium chloride, rubidium chloride, cesium fluoride, cesium chloride, cesium bromide, and cesium iodide. As a compound containing such an atom X, as needed, you may use individually by 1 type, or may use 2 or more types of them together.

(About the mixing conditions of step (1), etc.)

In the step (1), the aqueous mixture (A) and the aqueous mixture (B) contain 1.2 to 2.0 moles of nitric acid (more preferably 1.2 to 1.9 moles, still more preferably 1.6 to 12 moles of molybdenum). 1.9 mol) is mixed. When the ratio of nitric acid at the time of such mixing is less than the above lower limit, the properties of the aqueous slurry (C) change remarkably, so that the obtained catalytic activity tends to decrease, while on the other hand, when the above upper limit is exceeded, the aqueous slurry (C) When the properties of , the methacrylic acid selectivity of the obtained catalyst tends to decrease.

Further, in the step (1), the ratio of the phosphorus atom to the molybdenum atom in the aqueous mixture (A) and the aqueous mixture (B) in the atomic ratio (P/Mo) is 1.2/12 to 1.8/12 (more than Preferably it is 1.3/12 - 1.7/12, More preferably, it is preferable to mix so that it may become 1.4/12 - 1.6/12). When the content of such phosphorus atoms is within the above range, it becomes possible to improve the conversion rate of the obtained catalyst, and a higher effect tends to be obtained in that a catalyst capable of producing methacrylic acid with good productivity can be produced.

Moreover, when adding the nitrate containing atom X to the said aqueous mixture (A) when containing the nitrate containing atom X, or when mixing the said aqueous mixture (A) and the said aqueous mixture (B), when adding the nitrate containing the atom X , in the aqueous slurry (C) obtained, the ratio of atoms X to molybdenum atoms exceeds 0/12 in atomic ratio (atoms X/Mo) and is 3/12 or less (more preferably 0.01/12 to 3/12) , more preferably 1.2/12 to 1.8/12, particularly preferably 1.2/12 to 1.6/12), and it is more preferable to use a nitrate containing atom X. By making the ratio of the atom X within the above range, it becomes possible to increase the performance and stability of the catalyst, and a higher effect tends to be obtained in that a catalyst capable of producing methacrylic acid with good productivity can be produced.

Moreover, when making the said aqueous mixture (B) contain a vanadium compound, or when adding a vanadium compound at the time of mixing the said aqueous mixture (A) and the said aqueous mixture (B), in the aqueous slurry (C) obtained , the ratio of vanadium atoms to molybdenum atoms exceeds 0/12 in atomic ratio (V/Mo) and is 3/12 or less (more preferably 0.01/12 to 3/12, still more preferably 0.4/12 to 0.6 /12, particularly preferably 0.45/12 to 0.6/12), it is more preferable to use a vanadium compound. When the content of such vanadium atoms is within the above range, it becomes possible to produce a catalyst with high activity, and a higher effect tends to be obtained in that a catalyst capable of producing methacrylic acid with good productivity can be produced.

Thus, in the step (1), an aqueous slurry (C) can be obtained by mixing the aqueous mixture (A) containing nitric acid and a phosphorus compound with the aqueous mixture (B) containing a molybdenum compound.

In addition, the specific method for obtaining the said aqueous slurry (C) is although it does not restrict|limit, For example, in the said aqueous mixture (B) maintained at the temperature (30-90 degreeC) heated at the time of preparation under stirring conditions, The aqueous mixture (A) is added dropwise, and then the obtained mixture is stirred while maintaining at a holding temperature of 100°C or higher (more preferably 100-200°C, still more preferably 110-150°C) in a closed state. It is preferable to employ|adopt the method of obtaining an aqueous slurry (C). As a method of stirring the mixture while maintaining the mixture at a holding temperature of 100° C. or higher (more preferably 100 to 200° C., still more preferably 110 to 150° C.) in a closed state, for example, autoclave, etc. It is preferable to employ a method in which the mixture is sealed in a reaction vessel of , and stirred under the conditions of the holding temperature in a closed state. The holding time at such a holding temperature is preferably 0.1 hours or more (more preferably 2 hours or more) from the viewpoint of catalytic activity, and is preferably 20 hours or less from the viewpoint of productivity. In addition, the pressure conditions for stirring at the holding temperature in the sealed state are not particularly limited, but it is usually preferably in the range of 0.10 to 2.0 MPa in absolute pressure (more preferably in the range of 0.11 to 0.60 MPa). . Usually, by setting the above-mentioned holding temperature in the sealed state, it is possible to achieve such a pressure without special adjustment by the vapor pressure of water depending on the type of the mixture, etc., but depending on the type, etc., nitrogen or You may adjust suitably by pressurizing using inert gas, such as helium. In addition, when maintaining at the holding temperature of 100 degreeC or more in an airtight container, you may adjust the pressure in a container, For example, when maintaining at a holding temperature of 100 degreeC or more in an airtight container, a pressure adjustment means, a pressure detection means, pressure control. Using an airtight container suitably equipped with a means etc., you may adjust a pressure so that a threshold value may be set to the magnitude|size of the pressure in an airtight container, and it may hold|maintain at a specific pressure. As such a pressure adjustment method, for example, when the pressure in the sealed container exceeds a specific threshold using a sealed container provided with a pressure regulating valve, a relief valve, etc. as a pressure regulating means, a pressure regulating valve After adjusting the pressure in the sealed container so that the pressure is below the threshold value by opening a valve such as a relief valve or the like, the pressure in the container is maintained so that the pressure below the threshold value is maintained by closing the valve such as the pressure control valve or the relief valve again. A method of adjusting the pressure may be employed.

Moreover, it is preferable to use for the process (2) mentioned later, maintaining the aqueous slurry (C) obtained in this way at the said holding temperature. Thereby, it becomes possible to stabilize the catalyst physical properties.

In the aqueous slurry (C) obtained in this way, depending on the component used for the aqueous mixture (A) and the component used for the aqueous mixture (B), ammonium ion (NH ₄ ⁺ ) is contained _{along with the nitrate ion (NO 3} ^{− )} can be Moreover, as such an aqueous slurry (C), it is preferable that it contains a _{nitrate ion (NO 3} ⁻ ) and an ammonium ion (NH ₄ ^{+ ).} Examples of the source of such ammonium ions include ammonium salts of molybdic acid, ammonium salts such as ammonium vanadate (ammonium metavanadate), and ammonium salts other than these ammonium salts (ammonium nitrate, ammonium carbonate, hydrogen carbonate). ammonium, ammonium acetate, etc.), ammonia, etc. are mentioned. In addition, when mixing an aqueous mixture (A) and an aqueous mixture (B), you may add the said source of ammonium ion separately. Further, when the aqueous slurry (C) contains nitrate ions (NO ₃ ⁻ ) and ammonium ions (NH ₄ ⁺ ), the amount of ammonium ions per 1 mol of nitrate ions is 3.0 to 5.5 moles (more preferably It is more preferable that it is 3.2-5.0 mol, More preferably, it is 3.3-4.7 mol).

In the preparation of the aqueous slurry (C), when the aqueous mixture (A) and the aqueous mixture (B) are mixed, depending on the design of the target heteropolyacid compound, the aqueous mixtures (A) and (B) As another component not contained in ), a known component usable for preparation of the heteropolyacid compound may be appropriately added. As such other components, compounds containing atoms other than a phosphorus atom, a molybdenum atom and a copper atom can be preferably used. In addition, the compound containing such another atom is the same as the "compound containing another atom" demonstrated as what can be contained in the said aqueous mixture (A) and the said aqueous mixture (B).

[Step (2)]

A process (2) is a process of obtaining an aqueous slurry (E) by mixing the said aqueous slurry (C) and the aqueous mixture (D) containing a copper compound so that copper may become 0.01-0.20 mol with respect to 12 mol of molybdenum. Hereinafter, first, the aqueous mixture (D) used for a process (2) is demonstrated, and then, mixing conditions etc. are demonstrated.

(with respect to the aqueous mixture (D))

The aqueous mixture (D) contains a copper compound and may contain water for an aqueous mixture, and the form is not particularly limited, for example, an aqueous solution containing a copper compound may be used, and copper The aqueous slurry containing a compound may be sufficient. Moreover, as such water, ion-exchange water is preferable.

Although it does not restrict|limit especially as such a copper compound, For example, copper oxide, tetraammine copper dinitrate, copper carbonate, copper hydroxide, copper chloride, etc. are mentioned. As such a copper compound, a copper salt is preferable. As such a copper salt, a soluble viewpoint to copper nitrate is more preferable. In addition, such a copper compound may be used individually by 1 type as needed, or may use 2 or more types of them together.

Moreover, it is preferable that the said aqueous mixture (D) contains the compound containing the said atom Y other than the said copper compound further. The compound containing the said atom Y (preferably Sb) and the said copper compound may be added simultaneously, and may be added separately. Examples of the compound containing the atom Y include oxoacids, oxoates, oxides, carbonates, hydroxides, and halides containing the above atom Y. If necessary, two or more of them may be used. do. Examples of the compound containing the atom Y include an arsenic compound, an antimony compound, a boron compound, a silver compound, a bismuth compound, an iron compound, a cobalt compound, a lanthanum compound, and a cerium compound. Among them, an antimony compound is more preferable. do. Thus, it is preferable to make the said aqueous mixture (D) contain an antimony compound other than the said copper compound.

Antimony trioxide, antimony tribromide, antimony trichloride, antimony triiodide, antimony triacetate, triethoxyantimony etc. are mentioned as such an antimony compound. Such an antimony compound may be used individually by 1 type as needed, or may use 2 or more types together. Moreover, it is more preferable to use antimony trioxide from a viewpoint which does not contain a halogen element or an organic compound as an anion among such antimony compounds.

Further, in the aqueous mixture (D), in addition to the compound containing the atom Y described above, according to the design of the desired heteropolyacid compound, a known component that can be used for the preparation of the heteropolyacid compound can be appropriately used, and a phosphorus atom, a molybdenum atom and compounds containing atoms other than copper atoms can be appropriately used. In addition, the compound containing such another atom is the same as the "compound containing another atom" demonstrated as what can be contained in the said aqueous mixture (A) and the said aqueous mixture (B). Here, as a compound made into the said aqueous mixture (D), it is preferable to select and use suitably things other than the component contained in the said aqueous slurry (C). For example, when the compound or vanadium compound containing the said atom X is contained in the said aqueous slurry (C), it is preferable to select and use compounds other than those compounds.

In addition, the method for preparing such an aqueous mixture (D) is not specifically limited, For example, a copper compound and water are mixed (if necessary, another component (the said atom Y) with a copper compound and water. A method of preparing by adding and mixing a compound or acid containing Moreover, it is preferable that the quantity of the water used at the time of preparation of such an aqueous mixture (D) is 40-90 mass % (more preferably 45-70 mass %) with respect to the aqueous mixture (D) obtained. In addition, when preparing the said aqueous mixture (D), the mixing order in particular of each component mentioned above, temperature, stirring conditions, etc. are not restrict|limited, What is necessary is just to set suitably.

(About the mixing conditions of step (2), etc.)

In the step (2), the aqueous slurry (C) and the aqueous mixture (D) contain 0.01 to 0.20 moles (more preferably 0.10 to 0.20 moles, still more preferably 0.11 to 0.20 moles) of copper with respect to 12 moles of molybdenum. 0.15 mol). When the content of such copper is less than the above lower limit, the activity of the obtained catalyst tends to decrease, while on the other hand, when the above upper limit is exceeded, the methacrylic acid selectivity of the obtained catalyst tends to decrease.

When the aqueous mixture (D) contains the compound containing the atom Y, or when the compound containing the atom Y is added at the time of mixing the aqueous slurry (C) and the aqueous mixture (D), the resulting aqueous solution In the slurry (E), the content ratio of atoms Y to molybdenum atoms exceeds 0/12 in atomic ratio (atomic Y/Mo) and is 3/12 or less (more preferably 0.01/12 to 3/12, further It is more preferable to use a compound containing the atom Y so as to preferably be 0.1/12 to 3/12). By making the content rate of such an atom Y into the said range, it becomes possible to manufacture the catalyst which can manufacture methacrylic acid with favorable productivity.

In addition, in the aqueous slurry (E) obtained, ammonium ions (NH ₄ ⁺ ) may be contained _{together with nitrate ions (NO 3} ^{− ).} It is preferable that ammonium ion is 1-20 mol with respect to this.

In the preparation of the aqueous slurry (E), when the aqueous slurry (C) and the aqueous mixture (D) are mixed, depending on the design of the target heteropolyacid compound, the aqueous slurry (C) and the aqueous mixture (D) As another component not contained in the mixture (D), a known component usable for preparation of the heteropolyacid compound may be appropriately added. As such other components, compounds containing atoms other than a phosphorus atom, a molybdenum atom and a copper atom can be preferably used. In addition, the compound containing such another atom is the same as the "compound containing another atom" demonstrated as what can be contained in the said aqueous mixture (A) and the said aqueous mixture (B).

Further, the specific method for mixing the aqueous slurry (C) and the aqueous mixture (D) to obtain the aqueous slurry (E) is not particularly limited, for example, 100° C. or higher in a closed state (more preferably In the aqueous slurry (C) maintained at a holding temperature of 100 to 200 ° C., more preferably 110 to 150 ° C.) under stirring conditions, the aqueous mixture (D) is added, and thereafter, the resulting mixture is sealed. It is preferable to employ|adopt the method of obtaining the said aqueous|water-based slurry (E) by stirring, maintaining at the said holding temperature in a state. As a method of stirring the mixture while maintaining the mixture at the holding temperature in a closed state, for example, in a reaction vessel such as an autoclave, it is preferable to employ a method of stirring under the conditions of the holding temperature in a closed state. . The holding time at such a holding temperature is preferably 0.1 hours or more (more preferably 2 hours or more) from the viewpoint of catalytic activity of the compound obtained, and is preferably 20 hours or less from the viewpoint of productivity. In addition, the pressure conditions for stirring at the holding temperature in the sealed state are not particularly limited, but it is usually preferably in the range of 0.10 to 2.0 MPa in absolute pressure (more preferably in the range of 0.11 to 0.60 MPa). . The size of such a pressure is usually a size that can be achieved without special adjustment due to the vapor pressure of water in the mixture by setting the holding temperature in the sealed state, but depending on the type of aqueous mixture to be used, etc., if necessary , you may adjust the magnitude|size of a pressure suitably by pressurizing using inert gas, such as nitrogen or helium. In addition, when maintaining at a holding temperature of 100° C. or higher in an airtight container, using an airtight container suitably equipped with a pressure adjusting means, a pressure detecting means, a pressure controlling means, etc., by appropriately setting the threshold value of the pressure in the hermetically sealed container It may be adjusted by pressure. Thus, when stirring, maintaining the mixture obtained at the said holding temperature, you may hold|maintain at the said holding temperature, adjusting a pressure appropriately.

Further, the aqueous slurry (C) obtained in the step (1) and the aqueous slurry (E) obtained in the step (2) are each sealed from the viewpoint of making it possible to obtain a compound having a more excellent catalytic activity. What is obtained by holding|maintaining at the said holding temperature (holding temperature of 100 degreeC or more) in a container is preferable. Moreover, as said aqueous slurry (E), what is obtained by performing a process (2) by the method as described in the following a)-c) among them is more preferable.

(a) After mixing the aqueous slurry (C) maintained at a holding temperature of 100°C or higher in an airtight container and the aqueous mixture (D), the aqueous slurry (E) is obtained by holding the aqueous slurry (C) at a holding temperature of 100°C or higher in an airtight container.

B) After mixing the aqueous slurry (C) maintained at a holding temperature of 100° C. or higher in an airtight container and the aqueous mixture (D), an aqueous slurry (E) is obtained without maintaining at a holding temperature of 100° C. or higher in an airtight container.

C) An aqueous slurry (E) is obtained by mixing the aqueous slurry (C), which is not maintained at a holding temperature of 100°C or higher in an airtight container, and the aqueous mixture (D), and then maintaining it at a holding temperature of 100°C or higher in an airtight container. .

Among these methods, it is preferable to perform the step (2) by the method described in the above (a). In addition, in the case of employing the method described in the above a) or b), when mixing the aqueous slurry (C) maintained at 100°C or higher in an airtight container with the aqueous mixture (D), 100°C or higher in the airtight container To the aqueous slurry (C) maintained at the holding temperature, it is preferable to add the aqueous mixture (D).

Moreover, the manufacturing method of the heteropolyacid compound of this invention should just be a method of obtaining a heteropolyacid compound using the aqueous slurry (E) obtained by implementing the process (1) and (2) as mentioned above. In the method for producing the heteropolyacid compound of the present invention, after obtaining the aqueous slurry (E) by the step (2), a step of drying the aqueous slurry (E) (the above-mentioned step (3)) is performed, Then, it is more preferable to employ the method of obtaining a heteropolyacid compound by implementing the process of calcining the dried product of the obtained aqueous slurry (E). Hereinafter, the process which can be suitably employ|adopted for such a drying process and a baking process is demonstrated.

[Drying step: step (3)]

Such a drying process (process (3)) is a process of drying the said aqueous slurry (E). The drying method of such an aqueous slurry (E) is not particularly limited, and for example, a method commonly used in this field, such as an evaporation drying method, a spray drying method, a drum drying method, an airflow drying method, etc. can be appropriately adopted. . Further, the drying conditions may be appropriately set so that the moisture content in the aqueous slurry (E) is sufficiently reduced, and there is no particular limitation, but it is preferable that the drying temperature conditions be less than 300°C.

Moreover, before implementing the below-mentioned baking process (including the pre-firing process mentioned later) with respect to the dried material obtained by drying the said aqueous slurry (E), if necessary, a desired shape (ring shape, pellet shape, You may perform the shaping|molding process shape|molding in spherical shape, cylindrical shape, etc.). For such a molding treatment, for example, a method commonly used in this field, such as tablet molding and extrusion molding, can be appropriately employed. Moreover, in the case of such a shaping|molding process, you may add water, a shaping|molding auxiliary agent, a pore agent, etc. to the said dried material as needed. As such a shaping|molding auxiliary agent, ammonium nitrate etc. other than a ceramic fiber and a glass fiber are mentioned, for example. The ceramic fiber is preferably a biosoluble fiber. In particular, ammonium nitrate not only has a function as a molding aid, but also has a function as a pore agent.

The biosoluble fiber _{contains at least one selected from Na 2} O, K ₂ O, CaO, MgO, SrO and BaO, and their content in the biosoluble fiber is 18 to 43 mass%, and further with containing from SiO _2, it is preferred that the content of the bio-soluble fibers from 50 to 82% by weight. It is preferable that the biosoluble fiber contains MgO and CaO, or MgO and SrO, and alkaline-earth silicate wool is mentioned as this example.

A biosoluble fiber may be used individually by 1 type, and 2 or more types may be used together. Moreover, you may use together with ceramic fibers, such as a silica-alumina fiber and an alumina fiber, a biosoluble fiber.

It is preferable that the usage-amount of a ceramic fiber is 1-10 mass parts with respect to the dried product obtained by drying an aqueous slurry (E).

It is preferable that the average fiber length of a ceramic fiber is 1-1000 micrometers.

It is preferable that the average fiber diameter of a ceramic fiber is 1-7 micrometers.

Moreover, about the molded object obtained by such a shaping|molding process (henceforth may be referred to as a dried product), since it becomes possible to obtain a uniform and more stable heteropolyacid compound, before implementing the baking process mentioned later, temperature control and humidity control process It is preferable to carry out The method of such temperature control and humidity control treatment is not particularly limited, but for example, a method of exposing the molded article to an atmosphere of 10 to 60% relative humidity under a temperature condition of 40 to 100° C. for about 0.5 to 10 hours is adopted. desirable. Such temperature control and humidity control treatment may be performed, for example, in a temperature-controlled and humidity-controlled tank, or may be performed by spraying the temperature-controlled and humidity-controlled gas onto the molded body, and the specific treatment method is not particularly limited. Moreover, although air is normally used as atmospheric gas at the time of performing such a temperature control and humidity control process, you may use inert gas, such as nitrogen.

In addition, from the viewpoint of removing ammonium nitrate contained in the dried product obtained by such a drying step and changing the structure of the heteropolyacid compound, prior to firing described later, 180 to It is preferable to carry out the treatment (pre-firing step) maintained at a temperature of about 300°C.

[Firing process]

Such a baking process is a process of baking the dried product of the obtained aqueous slurry (E). It does not restrict|limit especially as a baking method of such a dried material, A method normally used in this field|area can be employ|adopted suitably. In addition, such a calcination process may be implemented, for example in the atmosphere of oxidizing gas, such as oxygen, and may be implemented in the atmosphere of non-oxidizing gas, such as nitrogen, The calcination temperature is preferably 300 degreeC or more. Moreover, when implementing the said pre-firing process prior to such a baking process, it is preferable to implement a baking process at the temperature higher than the temperature employ|adopted in the said pre-firing process.

Moreover, in such a calcination process, especially, when the heteropolyacid compound obtained is used as a catalyst, from a viewpoint that it becomes possible to make catalytic activity higher, a method of performing multi-step calcination in an atmosphere of an oxidizing gas or a non-oxidizing gas It is more preferable to employ a two-stage firing method in which the first-stage firing is carried out in an atmosphere of an oxidizing gas, and then the second-stage firing is performed in an atmosphere of a non-oxidizing gas. .

The oxidizing gas used for such baking is a gas containing an oxidizing substance, for example, oxygen containing gas is mentioned. When an oxygen-containing gas is used, the oxygen concentration is usually about 1 to 30% by volume, and as an oxygen source, air or pure oxygen is usually used, and is diluted with an inert gas as necessary. Moreover, although water|moisture content may be made to exist in the said oxidizing gas as needed, the density|concentration is 10 volume% or less normally. As an oxidizing gas, especially, air is preferable. Firing performed in an oxidizing gas atmosphere is normally performed in the airflow of such an oxidizing gas. Moreover, the temperature of the baking performed in an oxidizing gas atmosphere becomes like this. Preferably it is 360-410 degreeC, More preferably, it is 380-400 degreeC.

The non-oxidizing gas used for baking is a gas which does not contain an oxidizing substance like oxygen substantially, For example, inert gas, such as nitrogen, carbon dioxide, helium, and argon, is mentioned. Moreover, although water|moisture content may be made to exist in the said non-oxidizing gas as needed, the density|concentration is 10 volume% or less normally. As a non-oxidizing gas, nitrogen is especially preferable. Firing performed in a non-oxidizing gas atmosphere is normally performed in the airflow of such a non-oxidizing gas. Moreover, the temperature of the baking performed in a non-oxidizing gas atmosphere becomes like this. Preferably it is 420-500 degreeC, More preferably, it is 420-450 degreeC.

Thus, in the calcination process using multi-step calcination, after calcining the dried product of the said aqueous slurry (E) at 360 degreeC - 410 degreeC in the said oxidizing gas atmosphere, it is 420 degreeC - 500 degreeC in a non-oxidizing gas atmosphere. It is more preferable to employ|adopt the process of baking (process (4)).

As described above, in the method for producing the heteropolyacid compound of the present invention, it is preferable to further include the drying step (step (3)) and the calcination step (preferably step (4)), whereby phosphorus and molybdenum are It becomes possible to obtain the heteropolyacid compound containing copper with more favorable efficiency. In addition, the heteropolyacid compound obtained by such a manufacturing method of the heteropolyacid compound of this invention becomes the same thing as the heteropolyacid compound of this invention mentioned later. Hereinafter, the heteropolyacid compound of this invention is demonstrated.

[Heteropolyacid compound]

The heteropolyacid compound of this invention is a heteropolyacid compound obtained by the manufacturing method of the said heteropolyacid compound of this invention.

Thus, the heteropolyacid compound of this invention is obtained by the manufacturing method of the said heteropolyacid compound of this invention. In addition, while it has been revealed that the structure of the heteropolyacid compound obtained by the method for producing the heteropolyacid compound of the present invention is a keggin-type structure containing elemental molybdenum and elemental phosphorus, for analysis of the state of elemental copper or element Y, Since it is necessary to estimate the structure based on the combination of multiple analysis results, it is technically impossible to analyze the structure, or significantly excessive economic expenditure or time is required to perform work to specify the structure. do it with Therefore, in this specification, what is called "impossible and impractical circumstances" exists in describing the heteropolyacid compound of this invention as "heteropolyacid compound obtained by the method for producing the heteropolyacid compound of the present invention".

The heteropolyacid compound of this invention may be a free heteropolyacid, or the salt of a heteropolyacid may be sufficient as it. Moreover, the acidic salt of a heteropolyacid (partially neutralized salt) is more preferable among such a heteropolyacid compound, and the acidic salt of a Keggin-type heteropolyacid is still more preferable.

Moreover, in this invention, the said heteropolyacid compound contains phosphorus, molybdenum, and copper. It is preferable that content of phosphorus in such a heteropolyacid compound is 1.2-1.8 mol (More preferably 1.3-1.7 mol, More preferably, it is 1.4-1.6 mol with respect to 12 mol of molybdenum). Moreover, it is preferable that content of copper in a heteropolyacid compound is 0.01-0.20 mol (More preferably 0.10-0.20 mol, More preferably, it is 0.11-0.15 mol) with respect to 12 mol of molybdenum.

Moreover, when such a heteropolyacid compound contains the said atom X, the content of the said atom X is more than 0 and 3 or less (more preferably 0.5-2, more preferably 1.2-1.8) with respect to 12 mol of molybdenum. it is preferable Moreover, when such a heteropolyacid compound contains the said atom Y, the content of the said atom Y is more than 0 and 3 or less (more preferably 0.01-3, more preferably 0.4-0.6) with respect to 12 mol of molybdenum. it is preferable Moreover, when the said heteropolyacid compound contains vanadium, it is preferable that content of vanadium exceeds 0 and 3 or less with respect to 12 mol of molybdenum (more preferably 0.01-3, More preferably, 0.4-0.6).

In addition, such a heteropolyacid compound of the present invention, the following formula (I):

P _a Mo _b Cu _c V _d X _e Y _f O _x (I)

(In formula (I), P represents a phosphorus atom, Mo represents a molybdenum atom, Cu represents a copper atom, V represents a vanadium atom, O represents an oxygen atom,

X represents at least one atom selected from the group consisting of a potassium atom, a rubidium atom, a cesium atom and a thallium atom,

Y represents at least one atom selected from the group consisting of an arsenic atom, an antimony atom, a boron atom, a silver atom, a bismuth atom, an iron atom, a cobalt atom, a lanthanum atom, and a cerium atom,

a to f represent values satisfying the conditions of 1.2 ≤ a ≤ 1.8, 0.01 ≤ c ≤ 0.2, 0.4 ≤ d ≤ 0.6, 1.2 ≤ e ≤ 1.8, and 0.4 ≤ f ≤ 0.6 when b is 12 , x represents a value determined by the oxidation state of each atom. In addition, e and f represent the total ratio of 2 or more types of atoms when X and Y are 2 or more types of atoms, respectively.)

It is preferable that it is a partially neutralized salt of the heteropolyacid represented by. In the above formula (I), from the viewpoint of the performance of the resulting catalyst, a cesium atom is more preferable as X (atom X), and an antimony atom is more preferable as Y (atom Y).

Moreover, it is preferable that such a heteropolyacid compound of this invention has a BET specific surface area of 5 m<2>/g - 20 m<2>/g (more preferably, 7 m<2>/g - 16 m<2>/g). If the BET specific surface area is less than the lower limit, catalyst activity tends to decrease and the catalyst life tends to be shortened. On the other hand, when the BET specific surface area exceeds the upper limit, the methacrylic acid selectivity of the catalyst tends to decrease. As a measuring method of such a BET specific surface area, the method of measuring by nitrogen adsorption is employable, for example.

In addition, the heteropolyacid compound obtained by the method for producing the heteropolyacid compound of the present invention is preferably used for, for example, a solid acid catalyst in a heterogeneous reaction, a catalyst in a homogeneous reaction in an aqueous solution, etc. can Examples of use as such a catalyst include a catalyst for unsaturated carboxylic acid production, a catalyst for hydration of organic compounds, a catalyst for transesterification, a catalyst for polymerization, a catalyst for dehydration, a catalyst for ether synthesis, and a catalyst for esterification. and the like. In addition, an example of use as such a catalyst for production of unsaturated carboxylic acid is gas phase catalytic oxidation of a compound selected from the group consisting of methacrolein, isobutylaldehyde, isobutane and isobutyric acid with molecular oxygen to produce methacrylic acid catalysts for preparing acrylic acid by vapor-phase catalytic oxidation of propylene or acrolein, and the like. It is preferable to use the said heteropolyacid compound as a catalyst at the time of manufacturing acrylic acid.

Above, the method for producing the heteropolyacid compound of the present invention and the heteropolyacid compound of the present invention have been described. Hereinafter, the method for producing methacrylic acid of the present invention will be described.

[Method for producing methacrylic acid]

In the method for producing methacrylic acid of the present invention, in the presence of the heteropolyacid compound obtained by the method for producing a heteropolyacid compound of the present invention, or the heteropolyacid compound of the present invention, methacrolein, isobutylaldehyde, isobutane and A method comprising the step of subjecting at least one compound selected from the group consisting of isobutyric acid (hereinafter, simply referred to as "methacrylic acid raw material" in some cases for convenience) to a gas phase catalytic oxidation reaction.

In such a method for producing methacrylic acid, since the heteropolyacid compound obtained by the method for producing the heteropolyacid compound of the present invention is used as a catalyst, methacrylic acid can be produced in an excellent yield.

In such a method for producing methacrylic acid, for example, a gas phase catalytic oxidation reaction is carried out by charging the heteropolyacid compound in a fixed bed multi-tubular reactor, and supplying the raw material gas containing the methacrylic acid raw material and oxygen thereto. You may adopt a method to do it. In addition, the method of advancing gas-phase catalytic oxidation reaction in such a manufacturing method of methacrylic acid is not limited to this, Reaction forms, such as a fluidized bed and a mobile bed, can also be employ|adopted. Moreover, as an oxygen source of oxygen used for gas-phase catalytic oxidation reaction, air and pure oxygen are used normally. Moreover, in such a raw material gas, nitrogen, carbon dioxide, carbon monoxide, water vapor|steam, etc. may contain as components other than the said methacrylic acid raw material and oxygen.

In addition, the methacrylic acid raw material contained in the said raw material gas does not necessarily need to be a high-purity refined product, For example, methacrolein is meta obtained by the gas phase catalytic oxidation reaction of isobutylene or t-butyl alcohol. The reaction product gas containing crolein may be used without purification with high-purity methacrolein. In addition, the number of methacrylic acid raw materials contained in the said raw material gas may be one, and 2 or more types may be sufficient as them.

Moreover, in such a manufacturing method of methacrylic acid, the reaction conditions of a gaseous-phase catalytic oxidation reaction may just be set suitably according to the kind etc. of the methacrylic acid raw material contained in raw material gas. For example, when methacrolein is used as the raw material for methacrylic acid, as reaction conditions that can be usually employed when using the raw material, the concentration of methacrolein in the raw material gas is 1 to 10% by volume, and water vapor The concentration is 1 to 30% by volume, the molar ratio of oxygen to methacrolein is 1 to 5, the space velocity is 500 to 5000 h ⁻¹ (standard state reference), and the reaction temperature is 250 to 350°C. In addition, the gas phase catalytic oxidation reaction may be carried out by adopting the conditions in which the reaction pressure is 0.1 to 0.3 MPa in absolute pressure. In addition, when isobutane is used as the raw material for methacrylic acid, the isobutane concentration in the raw material gas is set to 1-85% by volume, and the water vapor concentration is set to 3- 30% by volume, the molar ratio of oxygen to isobutane is 0.05 to 4, the space velocity is 400 to 5000 h ^-1 (standard state standard), the reaction temperature is 250 to 400°C, and the reaction You may implement a gas-phase catalytic oxidation reaction by employ|adopting the conditions which make a pressure into 0.1-1 MPa in absolute pressure. In addition, when isobutylaldehyde or isobutyric acid is used as the raw material for methacrylic acid, generally the same reaction conditions as those in the case where methacrolein is used as a raw material can be adopted. In addition, the "space velocity" here can be calculated|required by dividing the raw material gas supply amount per hour (L/h) passing through the inside of a reactor by the catalyst capacity (L) in a reactor.

After subjecting to the gas phase catalytic oxidation reaction in this way, the post-treatment operation of the reaction product gas containing the obtained methacrylic acid is not particularly limited, and a known method can be appropriately selected and used. Moreover, as post-treatment operation of such a reaction product gas, it is preferable to carry out the operation of separating and purifying, after condensing the reaction product gas or making it absorb in water, for example. Moreover, when such a separation and purification process is employ|adopted, when unreacted raw material of methacrylic acid is collect|recovered, the raw material can be reused (recycled). In addition, the exhaust gas after post-processing may be reused (recycled) as said inert gas source by performing processes, such as combustion, as needed.

In this way, in the presence of the heteropolyacid compound obtained by the method for producing the heteropolyacid compound of the present invention, or the heteropolyacid compound of the present invention, the methacrylic acid raw material is subjected to a gas phase catalytic oxidation reaction, whereby methacrylic acid can get

Further, the obtained methacrylic acid can be preferably used as a raw material for producing a methacrylic acid ester by, for example, reacting (esterification reaction) with an alcohol in the presence of an esterification catalyst. Examples of the alcohol used in the esterification reaction include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and ethylene glycol. can be heard Moreover, as one preferable embodiment of the method of manufacturing such a methacrylic acid ester, the embodiment which manufactures methyl methacrylate by using methanol as said alcohol is mentioned. Moreover, as such an esterification catalyst, acid catalysts, such as sulfuric acid and strongly acidic ion exchange resin, etc. are mentioned, for example. In addition, such an esterification reaction is, for example, Japanese Patent Publication No. 48-1369, Japanese Patent Publication No. 61-4378, Japanese Unexamined Patent Publication No. 6-298702, Japanese Unexamined Patent Publication No. 2003-26633, etc. You may carry out according to the described method.

Example

Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to the following Example. In addition, the air used in each Example and each comparative example contains 3.5-3.6 volume% of water|moisture content (equivalent to air|atmosphere), and nitrogen does not contain water|moisture content substantially.

(Example 1)

[Step for preparing aqueous mixture (A1)]

First, 26.14 g of 67.5 mass% nitric acid, 27.43 g of 75 mass% orthophosphoric acid, and _{38.19 g of cesium nitrate [CsNO 3} ] were dissolved in 224 g of ion-exchanged water heated to 40°C to obtain an aqueous mixture (A1). .

[Preparation step of aqueous mixture (B)]

In 330 g of ion-exchanged water heated to 40° C., _{297 g of hexaammonium chilmolybdate tetrahydrate [(NH 4} ) ₆ Mo ₇ O ₂₄ .4H ₂ O] was dissolved, and then ammonium metavanadate [NH ₄ VO ₃ ] 8.19 g was suspended to obtain an aqueous mixture (B).

[Step of Preparation of Aqueous Slurry (C1)]

While maintaining the temperature of the aqueous mixture (A1) and the aqueous mixture (B) at 40°C, the aqueous mixture (A1) is added dropwise to the aqueous mixture (B) under stirring conditions and mixed, and then the obtained mixture is sealed. An aqueous slurry (C1) was obtained by stirring while holding|maintaining at 120 degreeC for 5 hours in a container. Moreover, in such a mixing process, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the said aqueous mixture (A1) with respect to the molybdenum contained in the said aqueous mixture (B) was 2.0/12.

[Step for preparing aqueous mixture (D)]

In 100 g of ion-exchanged water, _{10.2 g of antimony trioxide [Sb 2} O ₃ ] and 13.44 g of a 30.6 mass% aqueous solution of copper nitrate trihydrate [Cu(NO ₃ ) ₂ .3H ₂ O] were suspended, and an aqueous mixture (D ) was prepared.

[Preparation step of aqueous slurry (E1)]

In the step of preparing the aqueous slurry (C1) described above, immediately after preparing the aqueous slurry (C1) in a sealed container, the aqueous slurry (C1) was maintained in a stirred state at a temperature of 120°C in the sealed container. ), an aqueous slurry (E1) was obtained by adding the aqueous mixture (D) and stirring the obtained mixture in an airtight container at 120°C for 5 hours. Further, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) to the molybdenum contained in the aqueous slurry (C1) was 0.12/12.

[Drying and sintering process of aqueous slurry (E1)]

Water was evaporated and dried by heating the aqueous slurry (E1) obtained as mentioned above to 135 degreeC in air|atmosphere, and the dried product was obtained. Next, 4 parts by mass of ceramic fibers, 15.1 parts by mass of ammonium nitrate, and 9.7 parts by mass of ion-exchanged water were added and kneaded with respect to 100 parts by mass of the obtained dried product, followed by extrusion molding into a cylindrical shape having a diameter of 5 mm and a height of 6 mm. Next, the obtained molded body is subjected to a temperature control and humidity control treatment of drying under conditions of a temperature of 90°C and a relative humidity of 30% for 3 hours, followed by a pre-baking treatment of holding at 220°C in an air stream for 22 hours and then at 250°C for 1 hour. was carried out. Then, the heteropolyacid compound (1) was obtained by performing the baking process hold|maintained for 4 hours at 390 degreeC in an air stream at 390 degreeC in an air stream, then 435 degreeC in a nitrogen stream with respect to the obtained molded object after that.

The heteropolyacid compound (1) thus obtained contains phosphorus (P), molybdenum (Mo), copper (Cu), vanadium (V), cesium (Cs) and antimony (Sb), and the heteropolyacid compound (1) The atomic ratio (P: Mo: Cu: V: Cs: Sb) of the metal elements contained in ) was 1.5: 12: 0.12: 0.5: 1.4: 0.5. In addition, the atomic ratio (Cu/Mo) of copper to molybdenum in the heteropolyacid compound (1) was 0.12/12. Further, from the above production method and atomic ratio, the heteropolyacid compound (1) is _{a partially neutralized salt represented by the formula: P 1.5} Mo ₁₂ Cu _0.12 V _0.5 Cs _1.4 Sb _0.5 O x (in addition, x in the formula is oxidation of each atom) It is a value determined by the state).

Moreover, for the heteropolyacid compound (1) obtained in this way, as a measuring device, Macsorb (registered trademark) HM model-1208 (trade name "Fully automatic specific surface area measuring device Macsorb (registered trademark)" manufactured by Mountec Co., Ltd.) was used to 200 After dehydration treatment was carried out for a total of 35 minutes at °C, the nitrogen adsorption isotherm was measured under the condition of 77 K, and the BET specific surface area was measured using the nitrogen adsorption isotherm. As a result of these measurements, it was found that the obtained heteropolyacid compound (1) had a BET specific surface area of 10.1 m 2 /g.

[Activity test of heteropolyacid compound (1)]

9 g of the obtained heteropolyacid compound (1) was charged into a glass microreactor having an inner diameter of 16 mm, and the furnace (temperature of the furnace for heating the microreactor) was heated to 355°C. Thereafter, the raw material gas prepared by mixing methacrolein, air, steam and nitrogen (composition: methacrolein 4% by volume, molecular oxygen 12% by volume, water vapor 17% by volume, nitrogen 67% by volume) was subjected to a space velocity of 670h ^The catalyst was initially deteriorated by supplying it into the microreactor under the condition of -1 and performing a reaction for 1 hour. Then, the furnace was set to 280 degreeC, and the raw material gas of the same composition as the above was supplied at the same space velocity as the above, and reaction was started. The outlet gas (gas after reaction) at the time of elapse of 1 hour from the start of such a reaction is sampled, analyzed by gas chromatography, based on the following formula, methacrolein conversion (%), methacrylic acid selectivity (%) And methacrylic acid yield (%) was calculated|required. Table 1 shows the results of the activity test.

Methacrolein conversion ratio (%) = [number of moles of reacted methacrolein ÷ number of moles of supplied methacrolein] × 100

Methacrylic acid selectivity (%) = [the number of moles of methacrylic acid produced / the number of moles of reacted methacrolein] × 100

Methacrylic acid yield (%) = [Methacrolein conversion (%) x methacrylic acid selectivity (%)] ÷ 100

(Example 2)

[Step for preparing aqueous mixture (A2)]

Except having changed the usage-amount of 67.5 mass % nitric acid into 24.83 g, operation similar to [preparation process of an aqueous mixture (A1)] employ|adopted in Example 1 was performed, and the aqueous mixture (A2) was obtained.

[Preparation step of aqueous slurry (C2)]

An aqueous slurry (C2) was obtained in the same manner as in the [preparation step of the aqueous slurry (C1)] employed in Example 1 except that the aqueous mixture (A2) was used instead of the aqueous mixture (A1). In the preparation of the aqueous slurry (C2), the same as that prepared in Example 1 was used as the aqueous mixture (B). Moreover, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the aqueous mixture (A2) to the molybdenum contained in the aqueous mixture (B) was 1.9/12.

[Preparation step of aqueous slurry (E2)]

Except for using the aqueous slurry (C2) instead of the aqueous slurry (C1), the same operation as the [preparation step of the aqueous slurry (E1)] employed in Example 1 was carried out to obtain an aqueous slurry (E2). In addition, at the time of preparation of such an aqueous slurry (E2), the thing similar to what was prepared in Example 1 was used for the aqueous mixture (D). Moreover, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) with respect to the molybdenum contained in the aqueous slurry (C2) was 0.12/12.

[Drying and sintering process of aqueous slurry (E2)]

An aqueous slurry (E2) was used instead of the aqueous slurry (E1), and the amounts of ammonium nitrate and ion-exchanged water added to 100 parts by mass of dry matter during extrusion were 14.7 parts by mass (ammonium nitrate) and 8.5 parts by mass, respectively. Except for changing to negative (ion-exchanged water), the same operation as the [drying and calcining step of the aqueous slurry (E1)] employed in Example 1 was carried out to obtain a heteropolyacid compound (2).

The heteropolyacid compound (2) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (2) (P:Mo:Cu:V:Cs) : Sb) was 1.5:12:0.12:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.12/12. In addition, as a result of obtaining the BET specific surface area of the heteropolyacid compound (2) by employing the same method as the method of measuring the BET specific surface area of the heteropolyacid compound (1) in Example 1, it was found that the BET specific surface area was 13.8 m 2 /g. there was.

[Activity test of heteropolyacid compound (2)]

An activity test was carried out in the same manner as [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (2) was used instead of the heteropolyacid compound (1). Table 1 shows the results of the activity test.

(Example 3)

[Step for preparing aqueous mixture (A3)]

Except having changed the usage-amount of 67.5 mass % nitric acid into 23.52 g, operation similar to [preparation process of aqueous mixture (A1)] employ|adopted in Example 1 was performed, and aqueous mixture (A3) was obtained.

[Step for preparing aqueous slurry (C3)]

An aqueous slurry (C3) was obtained in the same manner as [the preparation step of the aqueous slurry (C1)] employed in Example 1 except that the aqueous mixture (A3) was used instead of the aqueous mixture (A1). In preparation of the aqueous slurry (C3), the same as that prepared in Example 1 was used as the aqueous mixture (B). Further, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the aqueous mixture (A3) to the molybdenum contained in the aqueous mixture (B) was 1.8/12.

[Preparation step of aqueous slurry (E3)]

Except for using the aqueous slurry (C3) instead of the aqueous slurry (C1), the same operation as the [preparation step of the aqueous slurry (E1)] employed in Example 1 was carried out to obtain an aqueous slurry (E3). In addition, at the time of preparation of such an aqueous slurry (E3), the thing similar to what was prepared in Example 1 was used for the aqueous mixture (D). Moreover, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) with respect to the molybdenum contained in the aqueous slurry (C3) was 0.12/12.

[Drying and sintering step of aqueous slurry (E3)]

Aqueous slurry (E3) was used instead of aqueous slurry (E2), and the amount of ammonium nitrate added with respect to 100 parts by mass of dry matter during extrusion was changed to 14.7 parts by mass, except that the [aqueous slurry] adopted in Example 2 was used. Drying and sintering process of slurry (E2)], and the same operation as that of a slurry (E2) was performed, and the heteropolyacid compound (3) was obtained.

The heteropolyacid compound (3) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (3) (P:Mo:Cu:V: Cs:Sb) was 1.5:12:0.12:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.12/12. Further, as a result of obtaining the BET specific surface area of the heteropolyacid compound (3) by employing the same method as the method of measuring the BET specific surface area of the heteropolyacid compound (1) in Example 1, it was found that the BET specific surface area was 11.8 m 2 /g. there was.

[Activity test of heteropolyacid compound (3)]

An activity test was carried out in the same manner as [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (3) was used instead of the heteropolyacid compound (1). Table 1 shows the results of the activity test.

(Example 4)

[Step for preparing aqueous mixture (A4)]

Except having changed the usage-amount of 67.5 mass % nitric acid into 20.91 g, operation similar to [preparation process of aqueous mixture (A1)] employ|adopted in Example 1 was performed, and aqueous mixture (A4) was obtained.

[Step for preparing aqueous slurry (C4)]

An aqueous slurry (C4) was obtained in the same manner as in [the preparation step of the aqueous slurry (C1)] employed in Example 1 except that the aqueous mixture (A4) was used instead of the aqueous mixture (A1). In preparation of the aqueous slurry (C4), the same as that prepared in Example 1 was used as the aqueous mixture (B). Further, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the aqueous mixture (A4) to the molybdenum contained in the aqueous mixture (B) was 1.6/12.

[Step of Preparation of Aqueous Slurry (E4)]

An aqueous slurry (E4) was obtained in the same manner as in [the preparation step of the aqueous slurry (E1)] employed in Example 1 except that the aqueous slurry (C4) was used instead of the aqueous slurry (C1). In addition, at the time of preparation of such an aqueous slurry (E4), the thing similar to what was prepared in Example 1 was used for the aqueous mixture (D). Moreover, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) with respect to the molybdenum contained in the aqueous slurry (C4) was 0.12/12.

[Drying and sintering process of aqueous slurry (E4)]

[Aqueous slurry (E4) was used instead of aqueous slurry (E2), and the amount of ammonium nitrate added to 100 parts by mass of dry matter during extrusion was changed to 15.3 parts by mass, except that the [aqueous] Drying and sintering process of slurry (E2)], and the same operation as that of a slurry (E2) was performed, and the heteropolyacid compound (4) was obtained.

The heteropolyacid compound (4) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (4) (P:Mo:Cu:V: Cs:Sb) was 1.5:12:0.12:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.12/12. In addition, as a result of obtaining the BET specific surface area of the heteropolyacid compound (4) by employing the same method as the method of measuring the BET specific surface area of the heteropolyacid compound (1) in Example 1, it was found that the BET specific surface area was 12.0 m 2 /g. there was.

[Activity test of heteropolyacid compound (4)]

An activity test was carried out in the same manner as [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (4) was used instead of the heteropolyacid compound (1). Table 1 shows the results of the activity test.

(Example 5)

[Step for preparing aqueous mixture (A5)]

Except having changed the usage-amount of 67.5 mass % nitric acid into 15.68 g, operation similar to [preparation process of an aqueous mixture (A1)] employ|adopted in Example 1 was performed, and the aqueous mixture (A5) was obtained.

[Step for preparing aqueous slurry (C5)]

An aqueous slurry (C5) was obtained in the same manner as in [the preparation step of the aqueous slurry (C1)] employed in Example 1 except that the aqueous mixture (A5) was used instead of the aqueous mixture (A1). In preparation of the aqueous slurry (C5), the same as that prepared in Example 1 was used as the aqueous mixture (B). In addition, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the aqueous mixture (A5) to the molybdenum contained in the aqueous mixture (B) was 1.2/12.

[Preparation step of aqueous slurry (E5)]

Except for using the aqueous slurry (C5) instead of the aqueous slurry (C1), the same operation as the [preparation step of the aqueous slurry (E1)] employed in Example 1 was carried out to obtain an aqueous slurry (E5). In addition, at the time of preparation of such an aqueous slurry (E5), the thing similar to what was prepared in Example 1 was used for the aqueous mixture (D). Moreover, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) with respect to the molybdenum contained in the aqueous slurry (C5) was 0.12/12.

[Drying and sintering process of aqueous slurry (E5)]

[aqueous slurry (E5) was used instead of aqueous slurry (E2), and the amount of ammonium nitrate added to 100 parts by mass of dry matter during extrusion was changed to 15.0 parts by mass. Drying and sintering process of slurry (E2)], and the same operation as that of a slurry (E2) was performed, and the heteropolyacid compound (5) was obtained.

The heteropolyacid compound (5) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (5) (P:Mo:Cu:V: Cs:Sb) was 1.5:12:0.12:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.12/12.

[Activity test of heteropolyacid compound (5)]

An activity test was carried out in the same manner as [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (5) was used instead of the heteropolyacid compound (1). Table 1 shows the results of the activity test.

(Example 6)

[Step for preparing aqueous mixture (A6)]

Except having changed the usage-amount of 67.5 mass % nitric acid into 22.87 g, operation similar to [preparation process of aqueous mixture (A1)] employ|adopted in Example 1 was performed, and aqueous mixture (A6) was obtained.

[Step for preparing aqueous slurry (C6)]

An aqueous slurry (C6) was obtained in the same manner as in [the preparation step of the aqueous slurry (C1)] employed in Example 1 except that the aqueous mixture (A6) was used instead of the aqueous mixture (A1). In preparation of the aqueous slurry (C6), the same as that prepared in Example 1 was used as the aqueous mixture (B). Further, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the aqueous mixture (A6) to the molybdenum contained in the aqueous mixture (B) was 1.75/12.

[Preparation step of aqueous slurry (E6)]

Except for using the aqueous slurry (C6) instead of the aqueous slurry (C1), the same operation as [the preparation step of the aqueous slurry (E1)] employed in Example 1 was carried out to obtain an aqueous slurry (E6). In addition, at the time of preparation of such an aqueous slurry (E6), the thing similar to what was prepared in Example 1 was used for the aqueous mixture (D). Moreover, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) with respect to the molybdenum contained in the aqueous slurry (C6) was 0.12/12.

[Drying and sintering process of aqueous slurry (E6)]

The [aqueous The process similar to drying and calcination process of slurry (E2)] was performed, and the heteropolyacid compound (6) was obtained.

The heteropolyacid compound (6) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (6) (P:Mo:Cu:V: Cs:Sb) was 1.5:12:0.12:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.12/12.

[Activity test of heteropolyacid compound (6)]

An activity test was carried out in the same manner as [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (6) was used instead of the heteropolyacid compound (1). Table 1 shows the results of the activity test.

(Comparative Example 1)

[Step for preparing aqueous mixture (A7)]

Except having changed the usage-amount of 67.5 mass % nitric acid into 32.67 g, operation similar to [preparation process of an aqueous mixture (A1)] employ|adopted in Example 1 was performed, and the aqueous mixture (A7) was obtained.

[Step for preparing aqueous slurry (C7)]

An aqueous slurry (C7) was obtained in the same manner as in [the preparation step of the aqueous slurry (C1)] employed in Example 1 except that the aqueous mixture (A7) was used instead of the aqueous mixture (A1). In preparation of the aqueous slurry (C7), the same as that prepared in Example 1 was used as the aqueous mixture (B). Further, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the aqueous mixture (A7) to the molybdenum contained in the aqueous mixture (B) was 2.5/12.

[Step of Preparation of Aqueous Slurry (E7)]

Except for using the aqueous slurry (C7) instead of the aqueous slurry (C1), the same operation as the [preparation step of the aqueous slurry (E1)] employed in Example 1 was carried out to obtain an aqueous slurry (E7). In addition, at the time of preparation of such an aqueous slurry (E7), the thing similar to what was prepared in Example 1 was used for the aqueous mixture (D). Moreover, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) with respect to the molybdenum contained in the aqueous slurry (C7) was 0.12/12.

[Drying and sintering process of aqueous slurry (E7)]

[Aqueous slurry (E7) was used instead of aqueous slurry (E2), and the amount of ammonium nitrate added to 100 parts by mass of dry matter during extrusion was changed to 13.7 parts by mass. The process similar to drying and calcination process of slurry (E2)] was performed, and the heteropolyacid compound (7) was obtained.

The heteropolyacid compound (7) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (7) (P:Mo:Cu:V: Cs:Sb) was 1.5:12:0.12:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.12/12. Further, as a result of obtaining the BET specific surface area of the heteropolyacid compound (7) by employing the same method as the method for measuring the BET specific surface area of the heteropolyacid compound (1) in Example 1, it was found that the BET specific surface area was 15.0 m 2 /g. there was.

[Activity test of heteropolyacid compound (7)]

An activity test was carried out in the same manner as [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (7) was used instead of the heteropolyacid compound (1). Table 2 shows the results of the activity test.

(Comparative Example 2)

[Step for preparing aqueous mixture (A8)]

Except having changed the usage-amount of 67.5 mass % nitric acid into 28.75 g, operation similar to [preparation process of aqueous mixture (A1)] employ|adopted in Example 1 was performed, and aqueous mixture (A8) was obtained.

[Step of Preparation of Aqueous Slurry (C8)]

An aqueous slurry (C8) was obtained in the same manner as in the [preparation step of the aqueous slurry (C1)] employed in Example 1 except that the aqueous mixture (A8) was used instead of the aqueous mixture (A1). In preparation of the aqueous slurry (C8), the same as that prepared in Example 1 was used as the aqueous mixture (B). Further, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the aqueous mixture (A8) to the molybdenum contained in the aqueous mixture (B) was 2.2/12.

[Preparation step of aqueous slurry (E8)]

Except for using the aqueous slurry (C8) instead of the aqueous slurry (C1), the same operation as the [preparation step of the aqueous slurry (E1)] employed in Example 1 was carried out to obtain an aqueous slurry (E8). In addition, at the time of preparation of such an aqueous slurry (E8), the thing similar to what was prepared in Example 1 was used for the aqueous mixture (D). Moreover, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) with respect to the molybdenum contained in the aqueous slurry (C8) was 0.12/12.

[Drying and sintering process of aqueous slurry (E8)]

[Aqueous slurry (E8) was used instead of aqueous slurry (E2), and the amount of ammonium nitrate added to 100 parts by mass of dry matter during extrusion was changed to 13.1 parts by mass. Drying and sintering process of slurry (E2)], and the same operation as that of a slurry (E2) was performed, and the heteropolyacid compound (8) was obtained.

The heteropolyacid compound (8) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (8) (P:Mo:Cu:V: Cs:Sb) was 1.5:12:0.12:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.12/12. In addition, as a result of obtaining the BET specific surface area of the heteropolyacid compound (8) by employing the same method as the method for measuring the BET specific surface area of the heteropolyacid compound (1) in Example 1, it was found that the BET specific surface area was 14.0 m 2 /g. there was.

[Activity test of heteropolyacid compound (8)]

An activity test was carried out in the same manner as [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (8) was used instead of the heteropolyacid compound (1). Table 2 shows the results of the activity test.

(Comparative Example 3)

[Step for preparing aqueous mixture (A9)]

Except having changed the usage-amount of 67.5 mass % nitric acid to 13.07 g, operation similar to [preparation process of aqueous mixture (A1)] employ|adopted in Example 1 was performed, and aqueous mixture (A9) was obtained.

[Step of Preparation of Aqueous Slurry (C9)]

An aqueous slurry (C9) was obtained in the same manner as in [the preparation step of the aqueous slurry (C1)] employed in Example 1 except that the aqueous mixture (A9) was used instead of the aqueous mixture (A1). In preparation of the aqueous slurry (C9), the same as that prepared in Example 1 was used as the aqueous mixture (B). Further, the molar ratio (nitric acid/molybdenum) of the nitric acid contained in the aqueous mixture (A9) to the molybdenum contained in the aqueous mixture (B) was 1.0/12.

[Preparation step of aqueous slurry (E9)]

An aqueous slurry (E9) was obtained in the same manner as in the [preparation step of the aqueous slurry (E1)] employed in Example 1 except that the aqueous slurry (C9) was used instead of the aqueous slurry (C1). In addition, at the time of preparation of such an aqueous slurry (E9), the thing similar to what was prepared in Example 1 was used for the aqueous mixture (D). Moreover, the molar ratio (copper/molybdenum) of the copper contained in the aqueous mixture (D) with respect to the molybdenum contained in the aqueous slurry (C9) was 0.12/12.

[Drying and sintering process of aqueous slurry (E9)]

Aqueous slurry (E9) was used instead of aqueous slurry (E2), and the amount of ammonium nitrate added to 100 parts by mass of dry matter during extrusion was changed to 17.2 parts by mass, except that [aqueous] employed in Example 2 was used. Drying and sintering process of slurry (E2)], and the same operation was performed, and the heteropolyacid compound (9) was obtained.

The heteropolyacid compound (9) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (9) (P:Mo:Cu:V: Cs:Sb) was 1.5:12:0.12:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.12/12.

[Activity test of heteropolyacid compound (9)]

An activity test was carried out in the same manner as in [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (9) was used instead of the heteropolyacid compound (1). Table 2 shows the results of the activity test.

(Comparative Example 4)

[Step of Preparation of Aqueous Slurry (C1)]

The same operation as the [process for preparing the aqueous mixture (A1)], [the preparation of the aqueous mixture (B)] and [the preparation of the aqueous slurry (C1)] employed in Example 1 were carried out, and the aqueous mixture (A1) was ), an aqueous mixture (B) and an aqueous slurry (C1) were obtained. In addition, in such a [step for preparing the aqueous slurry (C1)], the molar ratio of nitric acid contained in the aqueous mixture (A1) to the molybdenum contained in the aqueous mixture (B) (nitric acid/molybdenum) is 2.0/12 it was

[Step for preparing aqueous mixture (D')]

In 100 g of ion-exchanged water, _{10.2 g of antimony trioxide [Sb 2} O ₃ ] and 133.59 g of a 30.6 mass% aqueous solution of copper nitrate trihydrate [Cu(NO ₃ ) _{2 .3H 2} O] were suspended, and an aqueous mixture (D ') was prepared.

[Preparation step of aqueous slurry (E10)]

In the step of preparing the aqueous slurry (C1) described above, immediately after preparing the aqueous slurry (C1) in a sealed container, the aqueous slurry (C1) was maintained in a stirred state at a temperature of 120°C in the sealed container. ), an aqueous slurry (E10) was obtained by adding the aqueous mixture (D') and stirring the obtained mixture in an airtight container at 120°C for 5 hours. Further, the molar ratio (copper/molybdenum) of copper contained in the aqueous mixture (D') to the molybdenum contained in the aqueous slurry (C1) was 0.3/12.

[Drying and sintering process of aqueous slurry (E10)]

Aqueous slurry (E10) was used instead of aqueous slurry (E2), and the amount of ammonium nitrate added with respect to 100 parts by mass of dry matter during extrusion was changed to 12.6 parts by mass, except that the [aqueous slurry] adopted in Example 2 was used. Drying and sintering process of slurry (E2)], and the same operation as that of a slurry (E2) was performed, and the heteropolyacid compound (10) was obtained.

The heteropolyacid compound (10) thus obtained contains P, Mo, Cu, V, Cs and Sb, and the atomic ratio of the metal elements contained in the heteropolyacid compound (10) (P:Mo:Cu:V: Cs:Sb) was 1.5:12:0.3:0.5:1.4:0.5. In addition, the atomic ratio of copper to molybdenum (Cu/Mo) was 0.3/12.

[Activity test of heteropolyacid compound (10)]

An activity test was carried out in the same manner as [Activity test of heteropolyacid compound (1)] employed in Example 1 except that the heteropolyacid compound (10) was used instead of the heteropolyacid compound (1). Table 2 shows the results of the activity test.

As is clear from the results shown in Tables 1 and 2, when the heteropolyacid compound was prepared using the manufacturing method of the heteropolyacid compound of the present invention (Examples 1 to 6), the heteropolyacid compound was prepared using the manufacturing method employed in the comparative example. Contrary to the case of preparation, when methacrylic acid is produced from methacrolein using the obtained heteropolyacid compound as a catalyst in the gas phase catalytic oxidation reaction, the methacrolein conversion rate (%) and the methacrylic acid selectivity (%) It turned out that all can be made into a highly advanced thing, and it becomes possible to achieve a higher yield. From these results, when used as a catalyst in a gas phase catalytic oxidation reaction, the conversion rate (%) and selectivity (%) can be made sufficiently high, and in order to produce a heteropolyacid compound capable of achieving a higher yield, In the step of obtaining the aqueous slurry (C), it is necessary to mix the aqueous mixture (A) and the aqueous mixture (B) so that nitric acid is 1.2 to 2.0 mol with respect to 12 mol of molybdenum, and the aqueous slurry ( In the process of obtaining E), it turned out that it is necessary to mix the said aqueous slurry (C) and the said aqueous mixture (D) so that copper may become 0.01-0.20 mol with respect to 12 mol of molybdenum.

Industrial Applicability

As described above, according to the present invention, when used as a catalyst in a gas phase catalytic oxidation reaction, both the conversion rate and the selectivity can be made excellent, and it is possible to prepare a heteropolyacid compound which makes it possible to obtain a product in a higher yield. It becomes possible to provide a manufacturing method of a possible heteropolyacid compound, the heteropolyacid compound obtained by the manufacturing method, and the manufacturing method of methacrylic acid using this heteropolyacid compound. Therefore, the manufacturing method of the heteropolyacid compound of this invention can be used suitably as a method etc. for manufacturing the heteropolyacid compound used for the catalyst of a gas-phase catalytic oxidation reaction.

Claims (13)

A method for producing a heteropolyacid compound containing phosphorus, molybdenum, and copper, comprising the following steps (1) and (2):
[Step (1)] An aqueous slurry (C) by mixing the aqueous mixture (A) containing nitric acid and a phosphorus compound and the aqueous mixture (B) containing a molybdenum compound so that the nitric acid content is 1.2 to 2.0 moles with respect to 12 moles of molybdenum ) to obtain ;
[Step (2)] A step of obtaining an aqueous slurry (E) by mixing the aqueous slurry (C) and an aqueous mixture (D) containing a copper compound so that the copper content is 0.01 to 0.20 mol with respect to 12 mol of molybdenum. The method of claim 1,
In the said process (2), the said aqueous slurry (C) and the said aqueous mixture (D) are mixed so that copper may become 0.10-0.20 mol with respect to 12 mol of molybdenum, The manufacturing method of a heteropolyacid compound. 3. The method according to claim 1 or 2,
A method for producing a heteropolyacid compound, further comprising the following step (3) and the following step (4):
[Step (3)] A step of drying the aqueous slurry (E);
[Step (4)] A step of calcining the dried product of the aqueous slurry (E) at 360°C to 410°C in an oxidizing gas atmosphere, and then calcining in a non-oxidizing gas atmosphere at 420°C to 500°C. 4. The method according to any one of claims 1 to 3,
The method for producing a heteropolyacid compound, wherein the phosphorus compound is phosphoric acid. 5. The method according to any one of claims 1 to 4,
The method for producing a heteropolyacid compound, wherein the aqueous mixture (A) further contains a nitrate. 6. The method according to any one of claims 1 to 5,
The method for producing a heteropolyacid compound, wherein the molybdenum compound is a molybdate. 7. The method according to any one of claims 1 to 6,
The method for producing a heteropolyacid compound, wherein the aqueous mixture (B) further contains a vanadium compound. 8. The method according to any one of claims 1 to 7,
The method for producing a heteropolyacid compound, wherein the copper compound is a copper salt. 9. The method according to any one of claims 1 to 8,
The method for producing a heteropolyacid compound, wherein the aqueous mixture (D) further contains an antimony compound. The heteropolyacid compound obtained by the manufacturing method of the heteropolyacid compound in any one of Claims 1-9. 11. The method of claim 10,
The heteropolyacid compound has the following formula (I):
P _a Mo _b Cu _c V _d X _e Y _f O _x (I)
(In formula (I), P represents a phosphorus atom, Mo represents a molybdenum atom, Cu represents a copper atom, V represents a vanadium atom, O represents an oxygen atom,
X represents at least one atom selected from the group consisting of a potassium atom, a rubidium atom, a cesium atom and a thallium atom,
Y represents at least one atom selected from the group consisting of an arsenic atom, an antimony atom, a boron atom, a silver atom, a bismuth atom, an iron atom, a cobalt atom, a lanthanum atom, and a cerium atom,
a to f represent values satisfying the conditions of 1.2 ≤ a ≤ 1.8, 0.01 ≤ c ≤ 0.2, 0.4 ≤ d ≤ 0.6, 1.2 ≤ e ≤ 1.8, and 0.4 ≤ f ≤ 0.6 when b is 12 , x represents a value determined by the oxidation state of each atom. In addition, e and f represent the total ratio of 2 or more types of atoms when X and Y are 2 or more types of atoms, respectively.)
A heteropolyacid compound, which is a partially neutralized salt of a heteropolyacid represented by 12. The method of claim 10 or 11,
A heteropolyacid compound having a BET specific surface area of 5 m 2 /g to 20 m 2 /g. In the presence of the heteropolyacid compound obtained by the method for producing the heteropolyacid compound according to any one of claims 1 to 9, or the heteropolyacid compound according to any one of claims 10 to 12, methacrolein; A method for producing methacrylic acid, comprising the step of subjecting at least one compound selected from the group consisting of isobutylaldehyde, isobutane and isobutyric acid to a gas phase catalytic oxidation reaction.