Catalyst precursors and methods for their production; catalytically molded materials and methods for their production; methods for catalyst production; methods for the production of unsaturated carboxylic acids alpha, beta; and methods for the production of esters of unsaturated carboxylic acids alpha, beta.

Abstract

Provided is a catalyst precursor with which it is possible to manufacture a catalyst having a high yield of an α,β-unsaturated carboxylic acid, or a catalyst molded article.　The abovementioned problem is solved by: a catalyst precursor that contains a Keggin-type heteropolyacid, the catalyst precursor being used when oxidizing an α,β-unsaturated aldehyde to manufacture an α,β-unsaturated carboxylic acid, wherein the pore volume of the catalyst precursor is 0.005-0.15 mL / g; or a catalyst molded article that contains a catalyst component including phosphorus, molybdenum, and vanadium, the catalyst molded article being used when oxidizing an α,β-unsaturated aldehyde to manufacture an α,β-unsaturated carboxylic acid, wherein the pore volume of the catalyst molded article is 0.01-0.40 mL / g, and in a pore distribution curve pertaining to the catalyst molded article, IB / IA is 0.160-0.420, where IA is the height of the highest peak (peak A) and IB is the height of the second-highest peak (peak B) where peaks are present in a pore-diameter range of 0.05-10 μm.

Description

Catalyst precursor and method for producing same, catalyst molded body and method for producing same, catalyst production method, method for producing α,β-unsaturated carboxylic acid, and method for producing α,β-unsaturated carboxylic acid ester

[0001] The present invention relates to a catalyst precursor and a method for producing the same, a molded catalyst and a method for producing the same, a method for producing a catalyst, a method for producing an α,β-unsaturated carboxylic acid, and a method for producing an α,β-unsaturated carboxylic acid ester.

[0002] Heteropolyacid catalysts such as phosphomolybdic acid are known as catalysts for producing α,β-unsaturated carboxylic acids (hereinafter also referred to simply as "catalysts"), which are used when producing α,β-unsaturated carboxylic acids by oxidizing α,β-unsaturated aldehydes. Numerous studies have been conducted on methods for producing heteropolyacid catalysts, and most of these involve first preparing an aqueous solution or slurry containing the elements that make up the catalyst, then drying the aqueous solution or slurry to produce a catalyst precursor, which is then molded and / or calcined to produce the catalyst. It is known that the particle size and specific surface area of ​​the resulting catalyst precursor and catalyst vary depending on the slurry preparation and drying conditions, affecting the catalyst performance.

[0003] Patent Document 1 describes a method for producing a catalyst for producing methacrylic acid, which contains at least molybdenum and phosphorus as catalytic components and is used when producing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen.

[0004] Furthermore, in the production of α,β-unsaturated carboxylic acids, catalysts are generally formed into spherical bodies having a diameter of about 2 to 20 mm, or into cylindrical or columnar bodies having a diameter of about 2 to 10 mm and a length of about 2 to 20 mm, and these molded catalyst bodies are packed into a reactor for use. It is known that the performance of molded catalyst bodies varies depending on the pore structure, and many studies have been conducted to control the pore structure of molded catalyst bodies.

[0005] Patent Document 2 describes a catalyst used for producing methacrylic acid, which has a pore volume of 0.10 to 1.0 cc / g and a pore distribution in which the pore diameter is concentrated in the ranges of 1 to 10 μm and 0.1 to 1 μm.

[0006] Patent Document 3 describes a catalyst for producing methacrylic acid, which is characterized by having at least two peaks in the pore radius range of 0.5 to 10 μm in a pore size distribution chart.

[0007] Patent Document 4 describes a method for producing a catalyst for producing methacrylic acid, which contains at least molybdenum and phosphorus as catalytic components and is used when producing methacrylic acid by gas-phase catalytic oxidation of methacrolein with molecular oxygen, and describes that when the ratio of the apparent density of the dried product to the density of the molded product is within a specific range, it is possible to ensure both a pore volume effective for selectively oxidizing methacrolein and a catalyst loading amount effective for oxidizing methacrolein, thereby improving the yield of methacrylic acid.

[0008] JP 2011-224482 A JP 63-315148 A JP 2000-84412 A WO 2012 / 141076

[0009] However, the catalysts described in Patent Documents 1 to 4 did not necessarily provide a sufficient yield of α,β-unsaturated carboxylic acid. Therefore, from the viewpoint of further improving the catalytic performance, there is a need to develop a catalyst having physical properties more suitable for the production of α,β-unsaturated carboxylic acid.

[0010] As a result of intensive research into the above-mentioned problems, the inventors have found that the above-mentioned problems can be solved by using a catalyst precursor having a specific pore volume, or by using a catalyst molded body having a specific pore volume and pore distribution, and have completed the present invention.

[0011] That is, the present invention includes the following. [1]: A catalyst precursor containing a Keggin-type heteropolyacid, which is used in producing an α,β-unsaturated carboxylic acid by oxidizing an α,β-unsaturated aldehyde, the catalyst precursor having a pore volume of 0.005 to 0.15 mL / g. [2]: The catalyst precursor according to [1], which has a median diameter of 1 to 50 μm. [3]: The catalyst precursor according to [2], which has the median diameter of 5 to 40 μm. [4]: ​​The catalyst precursor according to any one of [1] to [3], which has the pore volume of 0.01 to 0.10 mL / g. [5]: The catalyst precursor according to any one of [1] to [4], which has a bulk density of 1.15 to 1.6 kg / L. [6]: The catalyst precursor according to any one of [1] to [5], which has a composition represented by the following formula (I): P ａ Mo ｂ V ｃ Cu ｄ A ｅ E ｆ G ｇ (NH ４ ) ｈ O ｉ (I) (In formula (I), P, Mo, V, Cu, NH ４and O represent phosphorus, molybdenum, vanadium, copper, ammonium, and oxygen, respectively. A represents at least one element selected from the group consisting of antimony, bismuth, arsenic, germanium, tellurium, selenium, silicon, and tungsten. E represents at least one element selected from the group consisting of iron, zinc, chromium, tantalum, cobalt, nickel, manganese, titanium, niobium, and cerium. G represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium. a to i represent the molar ratio of each component, satisfying b = 12, a = 0.5 to 3, c = 0.01 to 3, d = 0.01 to 2, e = 0 to 3, f = 0 to 3, g = 0.01 to 3, and h = 1 to 30, and i is the molar ratio of oxygen required to satisfy the valence of each component. ) [7]: A catalyst molded body used in producing an α,β-unsaturated carboxylic acid by oxidizing an α,β-unsaturated aldehyde, the catalyst containing a catalytic component containing phosphorus, molybdenum, and vanadium, wherein the catalyst molded body has a pore volume of 0.01 to 0.40 mL / g, and in a pore distribution curve of the catalyst molded body, the height of the highest peak (Peak A) in the pore diameter range of 0.05 to 10 μm is defined as IA, and the height of the second highest peak (Peak B) is defined as IB, where IB / IA is 0.160 to 0.420. [8]: The catalyst molded body according to [7], wherein the IB / IA is 0.200 to 0.400. [9]: A catalyst molded body having a specific surface area of ​​1 to 10 m ２

[10] : The catalyst molded body according to [7] or [8], wherein the specific surface area is 1.5 to 8 m / g. ２The molded catalyst according to [9], wherein the pore volume is 0.10 to 0.35 mL / g.

[11] : The molded catalyst according to any one of [7] to

[10] , wherein the pore volume is 0.10 to 0.35 mL / g.

[12] : The molded catalyst according to any one of [7] to

[11] , wherein the apexes of Peak A and Peak B are in the pore diameter range of 0.08 to 8 μm.

[13] : The molded catalyst according to any one of [7] to

[12] , wherein the molded catalyst is an extrusion molded product.

[14] : A method for producing a catalyst precursor according to any one of [1] to [6], comprising: (i) obtaining a solution or slurry (Liquid A1) containing phosphorus, molybdenum, and vanadium; (ii) adding a raw material compound (Compound B) containing an ammonium radical to the Liquid A1 to obtain a slurry (Liquid A2) having a pH of 3 or less; and (iii) drying the Liquid A2 to obtain dried particles, wherein in the step (ii), Compound B is added so as to satisfy the following formula (II): v / M=0.10 to 1.80 (II) (In formula (II), M is the number of moles (mol) of molybdenum contained in Liquid A1, and v is the addition rate (mol / h) of the ammonium radical.)

[15] : A method for producing a molded catalyst body from the catalyst precursor produced by the method according to

[14] , comprising: (iv) extruding the dried particles to obtain a molded catalyst body.

[16] : A method for producing a catalyst, comprising calcining the catalyst precursor according to any one of [1] to [6] or the catalyst precursor produced by the method according to

[14] .

[17] : A method for producing a molded catalyst according to any one of [7] to

[13] , comprising: (i) a step of obtaining a solution or slurry (Liquid A1) containing phosphorus, molybdenum, and vanadium, (ii) a step of adding a raw material compound (Compound B) containing an ammonium radical to the Liquid A1 to obtain a slurry (Liquid A2) having a pH of 3 or less, (iii) a step of drying the Liquid A2 to obtain dried particles, and (iv) a step of extrusion-molding the dried particles to obtain a molded catalyst, wherein in the step (ii), Compound B is added so as to satisfy the following formula (II):v / M=0.10 to 1.80 (II) (In formula (II), M is the number of moles (mol) of molybdenum contained in Liquid A1, and v is the addition rate (mol / h) of ammonium radicals.)

[18] : The method for producing a molded catalyst according to

[15] or

[17] , wherein the solids concentration of Liquid A2 is 30% by mass or less.

[19] : The method for producing a molded catalyst according to any one of

[15] and

[17] to

[18] , wherein, in Liquid A2, when the ratio of the total mass of dissolved elemental molybdenum, phosphorus, and vanadium elemental molybdenum to the total mass of elemental molybdenum, phosphorus, and vanadium elemental molybdenum, R is 5 to 25% by mass.

[20] : The method for producing a molded catalyst according to any one of

[15] and

[17] to

[19] , wherein, in the step (ii), Compound B is added to Liquid A1 at a temperature of 90 to 99° C. while stirring at a rotation speed of 70 to 140 rpm.

[21] : The method for producing a molded catalyst body according to any one of

[15] and

[17] to

[20] , wherein the A2 liquid is spray-dried in the step (iii).

[22] : The method for producing a molded catalyst body according to any one of

[15] and

[17] to

[21] , wherein the step (iv) includes the following steps (iv-1) and (iv-2): (iv-1) a step of mixing the dried particles, a liquid, and a binder to obtain a kneaded mixture; and (iv-2) a step of extruding the kneaded mixture using an extruder to obtain a molded catalyst body.

[23] : The method for producing a molded catalyst body according to

[22] , wherein the step (iv-1) involves mixing 15 to 60 parts by mass of the liquid and 0.05 to 15 parts by mass of the binder relative to 100 parts by mass of the dried particles.

[24] : A method for producing a molded catalyst according to

[22] or

[23] , wherein in (iv-2) above, extrusion molding is performed at an extrusion pressure of 0.1 to 30 MPa.

[25] : A method for producing an α,β-unsaturated carboxylic acid by oxidizing an α,β-unsaturated aldehyde using a catalyst obtained by molding and / or calcining the catalyst precursor according to any one of [1] to [6], or the molded catalyst according to any one of [7] to

[13] .

[26] : A method for producing an α,β-unsaturated carboxylic acid ester, wherein the α,β-unsaturated carboxylic acid produced by the method according to

[25] is esterified.

[0012] According to the present invention, it is possible to provide a catalyst precursor or a molded catalyst body that can produce a catalyst that provides a high yield of an α,β-unsaturated carboxylic acid.

[0013] 1 shows pore distribution curves of catalyst precursors in Examples 1-1, 1-4, and Comparative Example 1-1, and cumulative pore volume curves of catalyst precursors in Examples 1-1, 1-4, and Comparative Example 1-1.

[0014] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less.

[0015] [Catalyst Precursor] The catalyst precursor according to this embodiment is a precursor of a catalyst used in producing an α,β-unsaturated carboxylic acid by oxidizing an α,β-unsaturated aldehyde, and contains a Keggin-type heteropolyacid and has a pore volume of 0.005 to 0.15 mL / g. Use of a catalyst produced from such a catalyst precursor enables the production of an α,β-unsaturated carboxylic acid in high yield.

[0016] <Composition of catalyst precursor> The catalyst precursor according to this embodiment contains a Keggin-type heteropolyacid. A method for obtaining a catalyst precursor containing a Keggin-type heteropolyacid includes, for example, producing a catalyst precursor by the production method described below, and adjusting the pH of Solution A2 to 3 or less in step (ii). Whether or not the catalyst precursor contains a Keggin-type heteropolyacid can be confirmed by infrared absorption analysis using a NICOLET 6700 FT-IR (product name, manufactured by Thermo Electron) or the like, or by X-ray diffraction analysis using an X-ray diffractometer X'Pert PRO MPD (product name, manufactured by PANaltical) or the like.

[0017] The catalyst precursor according to this embodiment preferably contains phosphorus, molybdenum, and vanadium. From the viewpoint of improving the yield of α,β-unsaturated carboxylic acid, the ratio of the number of phosphorus atoms to the number of molybdenum atoms, taken as 12, is preferably 0.5 to 3, with the lower limit being more preferably 0.6 or more, even more preferably 0.7 or more, and particularly preferably 0.8 or more. The upper limit is more preferably 2.5 or less, and even more preferably 2 or less. Furthermore, the ratio of the number of vanadium atoms to the number of molybdenum atoms, taken as 12, is preferably 0.01 to 3, with the lower limit being more preferably 0.05 or more, even more preferably 0.1 or more, and particularly preferably 0.2 or more. The upper limit is more preferably 2.5 or less, even more preferably 2 or less, and particularly preferably 1.5 or less.

[0018] From the viewpoint of improving the yield of α,β-unsaturated carboxylic acid, the catalyst precursor according to this embodiment preferably has a composition represented by the following formula (I). Note that the catalyst precursor may contain small amounts of elements not represented by the following formula (I). P ａ Mo ｂ V ｃ Cu ｄ A ｅ E ｆ G ｇ (NH ４ ) ｈ O ｉ (I)

[0019] In formula (I), P, Mo, V, Cu, NH ４ and O represent phosphorus, molybdenum, vanadium, copper, ammonium, and oxygen, respectively. A represents at least one element selected from the group consisting of antimony, bismuth, arsenic, germanium, tellurium, selenium, silicon, and tungsten. E represents at least one element selected from the group consisting of iron, zinc, chromium, tantalum, cobalt, nickel, manganese, titanium, niobium, and cerium. G represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium. a to i represent the molar ratio of each component, satisfying b = 12, a = 0.5 to 3, c = 0.01 to 3, d = 0.01 to 2, e = 0 to 3, f = 0 to 3, g = 0.01 to 3, and h = 1 to 30, and i is the molar ratio of oxygen required to satisfy the valence of each component.

[0020] In the formula (I), from the viewpoint of improving the activity and life of the catalyst, G is preferably at least one element selected from the group consisting of potassium and cesium.

[0021] In the formula (I), from the viewpoint of improving the yield of the α,β-unsaturated carboxylic acid, the lower limit of a is preferably 0.6 or more, more preferably 0.7 or more, and even more preferably 0.8 or more. The upper limit of a is preferably 2.5 or less, more preferably 2 or less. The lower limit of c is preferably 0.05 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit of c is preferably 2.5 or less, more preferably 2 or less, and even more preferably 1.5 or less. The lower limit of d is preferably 0.03 or more, more preferably 0.05 or more, and even more preferably 0.1 or more. The upper limit of d is preferably 1.5 or less, more preferably 1 or less. The lower limit of e is preferably 0.01 or more, more preferably 0.1 or more. The upper limit of e is preferably 2.5 or less, more preferably 2 or less. The lower limit of f is preferably 0.01 or more, more preferably 0.03 or more. The upper limit of f is preferably 2 or less, more preferably 1.5 or less, and even more preferably 1 or less. The lower limit of g is preferably 0.1 or more, more preferably 0.3 or more, and even more preferably 0.5 or more. The upper limit of g is preferably 2.8 or less, more preferably 2.5 or less, and even more preferably 2 or less. The lower limit of h is preferably 2 or more, and more preferably 3 or more. The upper limit of h is preferably 20 or less, and more preferably 10 or less.

[0022] The molar ratio of each component is a value determined by dissolving the catalyst precursor in ammonia water and analyzing the components by ICP emission spectrometry. The molar ratio of ammonium radical is a value determined by analyzing the catalyst precursor by Kjeldahl method. Here, in the present invention, "ammonium radical" refers to ammonia (NH ３ ), and ammonium ion (NH ４ ＋ ) is a general term for

[0023] <Pore Volume of Catalyst and Catalyst Precursor> Increasing the pore volume of a catalyst increases the specific surface area of ​​the catalyst. This improves the activity of the catalyst and the yield of α,β-unsaturated carboxylic acid. On the other hand, if the pore volume of the catalyst is excessively large, the catalyst packing density decreases, reducing the catalyst weight that can be packed into a reactor of a certain volume. As a result, sufficient catalytic activity is not obtained, and the yield of α,β-unsaturated carboxylic acid decreases. In other words, an increase in pore volume has the effect of both improving and decreasing the yield of α,β-unsaturated carboxylic acid, so until now, it has been difficult to sufficiently improve the yield of α,β-unsaturated carboxylic acid by controlling the pore volume of the catalyst. Therefore, in the present invention, a catalyst pore volume more suitable for the production of α,β-unsaturated carboxylic acid was investigated.

[0024] The pore volume of the catalyst precursor according to this embodiment is 0.005 to 0.15 mL / g. When the pore volume is 0.005 mL / g or more, the specific surface area of ​​the catalyst produced from the catalyst precursor is sufficiently large, improving the yield of α,β-unsaturated carboxylic acid. When the pore volume is 0.15 mL / g or less, the packing density of the catalyst produced from the catalyst precursor is sufficiently large, increasing the weight of the catalyst that can be packed into a reactor of a given volume, thereby improving the yield of α,β-unsaturated carboxylic acid. The lower limit of the pore volume is preferably 0.01 mL / g or more, more preferably 0.05 mL / g or more. The upper limit is preferably 0.10 mL / g or less, more preferably 0.09 mL / g or less.

[0025] In this embodiment, the pore volume of the catalyst precursor means the pore volume within the catalyst precursor particles. The pore volume of the catalyst precursor can be measured using a mercury intrusion pore distribution analyzer. An example of a mercury intrusion pore distribution analyzer is AutoPore IV-9500 (product name, manufactured by Micromeritics). In the mercury intrusion pore distribution measurement, not only the pore volume within the catalyst precursor particles, which is the pore volume of the catalyst precursor in this embodiment, but also the pore volume derived from the physical voids between the catalyst precursor particles is measured. The pore volume of the catalyst precursor in this embodiment is calculated from the volume of pores with a pore diameter of 0.5 μm or less.

[0026] Examples of methods for obtaining a catalyst precursor having a pore volume within the above range include a method of producing a catalyst precursor by a production method described below, and adjusting the addition rate v (mol / h) of compound B, the temperature of liquid A1, and the stirring rotation speed of liquid A1 in step (ii), a method of adjusting the physical properties of liquid A2, and a method of adjusting the drying conditions in step (iii).

[0027] <Median diameter of catalyst precursor> The median diameter of the catalyst precursor according to this embodiment is preferably 1 to 50 μm. When the median diameter of the catalyst precursor is 1 μm or more, the raw material α,β-unsaturated aldehyde and the resulting α,β-unsaturated carboxylic acid can be sufficiently diffused in the pores derived from the gaps between the particles of the catalyst produced from the catalyst precursor, thereby improving the yield of α,β-unsaturated carboxylic acid. Furthermore, when the median diameter of the catalyst precursor is 50 μm or less, the reaction substrate can be easily diffused into the catalyst particles produced from the catalyst precursor, and a high yield of α,β-unsaturated carboxylic acid can be obtained even when the pore volume is small. The lower limit of the median diameter is more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit is more preferably 40 μm or less, and even more preferably 30 μm or less.

[0028] In the present invention, the median size refers to the particle size corresponding to a cumulative 50% by volume in a volume-based particle size distribution measured by a laser diffraction particle size distribution measurement method, and can be measured, for example, by a laser diffraction wet particle size distribution measurement device or a laser diffraction dry particle size distribution measurement device. Examples of laser diffraction wet particle size distribution measurement devices include the LA-700 (product name, manufactured by Horiba, Ltd.), the LA-900 (product name, manufactured by Horiba, Ltd.), the LA-960V2 (product name, manufactured by Horiba, Ltd.), and the SALD-7000 (product name, manufactured by Shimadzu Corporation). Examples of laser diffraction dry particle size distribution measurement devices include the SALD-2300 (product name, manufactured by Shimadzu Corporation).

[0029] Examples of methods for obtaining a catalyst precursor having a median diameter within the above range include a method of producing a catalyst precursor by a production method described below, and adjusting the addition rate v (mol / h) of compound B, the temperature of liquid A1, and the stirring rotation speed of liquid A1 in step (ii), a method of adjusting the physical properties of liquid A2, and a method of adjusting the drying conditions in step (iii).

[0030] <Bulk Density of Catalyst Precursor> The bulk density of the catalyst precursor according to this embodiment is preferably 1.15 to 1.6 kg / L. When the bulk density of the catalyst precursor is 1.15 kg / L or more, the weight of the catalyst that can be packed into a reactor of a certain volume increases, thereby obtaining sufficient catalytic activity in the production of an α,β-unsaturated carboxylic acid. Furthermore, when the bulk density of the catalyst precursor is 1.6 kg / L or less, the specific surface area of ​​the catalyst produced from the catalyst precursor is sufficiently large, improving the yield of an α,β-unsaturated carboxylic acid. The lower limit of the bulk density of the catalyst precursor is more preferably 1.2 kg / L or more, and even more preferably 1.25 kg / L or more. The upper limit of the bulk density of the catalyst precursor is more preferably 1.55 kg / L or less, and even more preferably 1.5 kg / L or less. In the present invention, the bulk density of the catalyst precursor is calculated by weighing the catalyst precursor into a 50 mL measuring cylinder and calculating the mass in a volume of 50 mL using the following formula: Bulk density of catalyst precursor (kg / L) = Weight (g) of catalyst precursor filled in a 50 mL measuring cylinder / 50 (mL).

[0031] [Method for Producing Catalyst Precursor] The catalyst precursor according to this embodiment can be produced in accordance with known methods for producing catalyst precursors, so long as it contains a Keggin-type heteropolyacid and has a pore volume of 0.005 to 0.15 mL / g. However, it is preferably produced by a method for producing a catalyst precursor according to this embodiment, which includes the following steps (i) to (iii): (i) obtaining a solution or slurry (Liquid A1) containing phosphorus, molybdenum, and vanadium; (ii) adding a raw material compound (Compound B) containing an ammonium radical to the Liquid A1 to obtain a slurry (Liquid A2) having a pH of 3 or less; and (iii) drying the Liquid A2 to obtain dried particles. Each step will be described in detail below.

[0032] <Step (i)> In step (i), a solution or slurry (solution A1) containing phosphorus, molybdenum, and vanadium is obtained. Solution A1 may contain other elements, such as Cu (copper), element A, element E, and element G in formula (I). Elements other than phosphorus, molybdenum, and vanadium in formula (I) can also be added in steps after step (i). Solution A1 can be prepared by dissolving or suspending raw material compounds of catalyst precursor components containing phosphorus, molybdenum, and vanadium in a solvent.

[0033] (Raw material compound for catalyst precursor component) The raw material compound for the catalyst precursor component is not particularly limited, and nitrates, carbonates, hydrogencarbonates, acetates, ammonium salts, oxides, halides, oxoacids, oxoacid salts, and the like of each constituent element of the catalyst precursor can be used alone or in combination of two or more thereof.

[0034] Examples of raw material compounds for phosphorus include phosphoric acid, phosphorus pentoxide, ammonium phosphate, etc. Examples of raw material compounds for molybdenum include molybdenum oxides such as molybdenum trioxide, ammonium molybdates such as ammonium paramolybdate and ammonium dimolybdate, molybdenum chloride, etc. Examples of raw material compounds for vanadium include ammonium metavanadate, vanadium pentoxide, vanadium chloride, vanadyl oxalate, etc.

[0035] When producing a catalyst precursor containing copper in addition to phosphorus, molybdenum, and vanadium, examples of the raw material compound for copper include copper sulfate, copper nitrate, copper oxide, copper carbonate, copper acetate, copper chloride, etc. When producing a catalyst precursor containing a G element in addition to phosphorus, molybdenum, and vanadium, examples of the raw material compound for the G element include nitrates, carbonates, hydrogencarbonates, hydroxides, sulfates, acetates, chlorides, etc., and it is preferable to use carbonates or hydrogencarbonates.

[0036] The raw material compounds of the catalyst precursor component may be used singly or in combination of two or more for each element constituting the catalyst precursor component. The total concentration of the raw material compounds of the catalyst precursor component in Liquid A1 is not particularly limited, but is preferably in the range of 5 to 90 mass %.

[0037] (Solvent) Examples of the solvent include water, ethyl alcohol, and acetone. These may be used alone or in combination of two or more. Among these, water is preferably used from an industrial viewpoint.

[0038] (Preparation of Solution A1) Solution A1 is preferably prepared by adding raw material compounds of the catalyst precursor component to a solvent in a preparation vessel and stirring the mixture while heating, thereby producing a sufficient amount of heteropolyacid suitable for producing an α,β-unsaturated carboxylic acid.

[0039] The heating temperature can usually be in the range of 30 to 150°C, and preferably in the range of 60 to 150°C. By setting the heating temperature to 60°C or higher, the rate of production of the heteropolyacid can be sufficiently increased, and by setting the heating temperature to 150°C or lower, evaporation of the solvent can be suppressed. The lower limit of the heating temperature is more preferably 80°C or higher, and even more preferably 90°C or higher. The upper limit of the heating temperature is more preferably 130°C or lower, and even more preferably 110°C or lower. Depending on the vapor pressure of the solvent used, the heating may involve concentration or reflux, or the heating may be carried out under pressurized conditions by operating in a sealed container.

[0040] The temperature rise rate is not particularly limited, but is preferably 0.8 to 15°C / min. By setting the temperature rise rate to 0.8°C / min or more, the time required for step (i) can be shortened. Furthermore, by setting the temperature rise rate to 15°C / min or less, the temperature can be raised using ordinary heating equipment. Stirring is performed with a stirring power of 0.01 kW / m ３ It is preferable to operate at a power of 0.05 kW / m or more. ３ It is more preferable to carry out the stirring at a power of 0.01 kW / m or more. ３ By setting the temperature and components of the A1 solution at or above 3.5 kW / m, local variations in temperature are reduced, and a structure suitable for producing an α,β-unsaturated carboxylic acid is stably formed. ３ It is preferable to do the following:

[0041] (Physical Properties of Solution A1) The pH of Solution A1 is not particularly limited, but is preferably 0.1 to 4, with a lower limit of 0.5 or more and an upper limit of 3 or less. Having a pH of 0.1 or more allows for stable performance of step (ii), described below. Having a pH of 4 or less allows for stable production of a Keggin-type heteropolyacid suitable for producing an α,β-unsaturated carboxylic acid. Examples of methods for adjusting the pH of Solution A1 to 0.1 to 4 include using molybdenum trioxide as the molybdenum raw material, or appropriately selecting raw material compounds and adjusting the content of nitrate ions and oxalate ions. The pH can be measured using a pH meter such as the D-21 (product name, manufactured by Horiba, Ltd.). Furthermore, whether or not a heteropolyacid salt having a Keggin structure has been formed can be confirmed by infrared absorption analysis using a NICOLET6700FT-IR (product name, manufactured by Thermo Electron Corporation) or the like, or by X-ray diffraction analysis using an X-ray diffractometer X'Pert PRO MPD (product name, manufactured by PANaltical Corporation) or the like.

[0042] <Step (ii)> In step (ii), a raw material compound containing an ammonium radical (compound B) is added to the solution A1 obtained in step (i) to obtain a slurry (solution A2) having a pH of 3 or less.

[0043] (Compound B) Examples of compound B include ammonium hydrogen carbonate, ammonium carbonate, ammonium nitrate, aqueous ammonia, ammonium phosphate, ammonium metavanadate, etc. These may be used alone or in combination of two or more.

[0044] Compound B may be dissolved or suspended in a solvent. Examples of the solvent include water, ethyl alcohol, and acetone. These may be used alone or in combination of two or more. Among these, water is preferably used from an industrial viewpoint.

[0045] (Addition of Compound B) Compound B is preferably added so as to satisfy the following formula (II): v / M=0.10 to 1.80 (II)

[0046] In formula (II), M is the number of moles (mol) of molybdenum contained in Liquid A1, and v is the addition rate of ammonium radicals (mol / h). Satisfying formula (II) means that the addition rate of ammonium radicals is sufficiently slow. This reduces the degree of supersaturation of the heteropolyacid ammonium salt produced by the addition of ammonium radicals, thereby appropriately increasing the particle size of the particles (primary particles) formed by nucleation growth of the heteropolyacid ammonium salt. Liquid A2 containing primary particles with such particle sizes can be dried in step (iii) described below to easily obtain a catalyst precursor with a desirable median size. Furthermore, the pores in the catalyst precursor originate from the gaps between the primary particles produced in Liquid A2. The larger the particle size of the primary particles, the more likely the primary particles tend to aggregate to reduce the gaps. Therefore, by drying Liquid A2 containing primary particles with the aforementioned particle size in step (iii) described below, a catalyst precursor with a specified pore volume can be easily obtained. v / M is 1.00 h －１ More preferably, it is 0.50h or less. －１ It is even more preferable that:

[0047] The temperature of Liquid A1 when Compound B is added is preferably 90 to 99°C. If the temperature of Liquid A1 when Compound B is added is high, the degree of supersaturation of the heteropolyacid ammonium salt produced by the addition of ammonium radicals will be reduced, resulting in a larger particle size of the primary particles formed in Liquid A2. This will also increase the median diameter of the catalyst precursor produced when Liquid A2 is dried in Step (iii) described below. By maintaining the temperature of Liquid A1 when Compound B is added within the above range, a catalyst precursor having a desirable median diameter can be easily obtained. Furthermore, the pores of the catalyst precursor originate from the voids between the primary particles formed in Liquid A2. The larger the particle diameter of the primary particles, the more likely the primary particles tend to aggregate to reduce the voids. Therefore, by drying Liquid A2 containing primary particles having the above particle size in Step (iii) described below, a catalyst precursor having a specified pore volume can be easily obtained. The lower limit of the temperature of Liquid A1 is more preferably 92°C or higher, and the upper limit is more preferably 98°C or lower.

[0048] When compound B is added, it is preferable to add liquid A1 while stirring at a rotation speed of 70 to 140 rpm. A higher rotation speed ensures sufficient stirring of liquid A1, reducing the degree of supersaturation of the heteropolyacid ammonium salt produced by the addition of ammonium radicals. This increases the particle size of the primary particles formed in liquid A2, and also increases the median diameter of the catalyst precursor produced when liquid A2 is dried in step (iii) described below. Furthermore, the pores of the catalyst precursor originate from the gaps between the primary particles produced in liquid A2. As the particle size of the primary particles increases, the primary particles tend to aggregate to reduce the gaps, resulting in a smaller pore volume of the catalyst precursor. By stirring liquid A1 at a rotation speed within the above range when compound B is added, a catalyst precursor having the specified pore volume and preferred median diameter can be easily obtained. The lower limit of the rotation speed is more preferably 100 rpm or more, and the upper limit is more preferably 130 rpm or less. Liquid A1 can be stirred using a stirring device such as a rotary blade stirrer.

[0049] (Physical Properties of Liquid A2) The pH of the resulting Liquid A2 is 3 or less, with the lower limit being preferably 2 or more and the upper limit being preferably 2.8 or less. By keeping the pH of Liquid A2 at 3 or less, a Keggin-type heteropolyacid suitable for producing an α,β-unsaturated carboxylic acid is stably produced. Methods for adjusting the pH of Liquid A2 to 3 or less include, for example, using molybdenum trioxide as the molybdenum raw material in the preparation of Liquid A1, or appropriately selecting raw material compounds and adjusting the content of nitrate ions or oxalate ions to adjust the pH of Liquid A1, or adjusting the content of ammonium ions or cesium ions in the preparation of Liquid A2.

[0050] The solids concentration of the resulting A2 liquid is preferably 30% by mass or less, and more preferably 22 to 27% by mass. This allows for appropriate droplet shrinkage due to solvent evaporation when A2 liquid is dried in step (iii) described below, making it possible to easily obtain a catalyst precursor having a desirable median diameter. Furthermore, when A2 liquid is dried in step (iii), the portions of the droplets from which the solvent has evaporated become the pores of the catalyst precursor. By ensuring that the solids concentration of A2 liquid is within the above range, the solvent is appropriately present in A2 liquid, making it possible to easily obtain a catalyst precursor having a specified pore volume. It is more preferable that the lower limit of the solids concentration of A2 liquid is 23% by mass or more, and the upper limit is 26.5% by mass or less.

[0051] The solids concentration of the A2 solution can be adjusted, for example, by the weight ratio of the raw material compounds and the solvent used, or the amount of the compound containing the B and G elements added. Increasing the amount of the B and G elements added promotes precipitation of the heteropolyacid salt produced, increasing the solids concentration. The solids concentration of the A2 solution is the value calculated by centrifuging the A2 solution to separate it into a solution and a solid, measuring the mass of each, and then using the following formula (III): solids concentration (%) = mass of solids (g) / total mass of the A2 solution (g) × 100 (III)

[0052] In Liquid A2, when the ratio of the total mass of dissolved molybdenum, phosphorus, and vanadium elements to the total mass of molybdenum, phosphorus, and vanadium elements is R, R is preferably 5 to 25 mass%, more preferably 5 to 20 mass%. This allows the dissolved components to precipitate in the voids between the primary particles in Liquid A2 when Liquid A2 is dried in step (iii) described below, thereby appropriately filling the voids and making it easy to obtain a catalyst precursor having a specified pore volume. The lower limit of R is more preferably 6 mass% or more, and the upper limit is more preferably 15 mass% or less.

[0053] Examples of methods for adjusting R include changing the amounts of compound B and the compound containing a G element added, or changing the temperature of solution A1 when compound B is added. Increasing the amounts of compound B and the compound containing a G element added increases the amount of heteropolyacid salt produced, thereby decreasing R. Furthermore, increasing the temperature of solution A1 when compound B is added increases the solubility of the heteropolyacid ammonium salt produced, thereby increasing R. R is a value calculated according to the following formula (IV) from the results of centrifuging solution A2 to separate it into a solution and a solid, measuring the masses of each, and analyzing the resulting solution and solid by ICP atomic emission spectrometry:

[0054] In formula (IV), m １ is the weight of the solution (g), m ２ is the weight of the solid content (g), M １Ｍｏ is the molybdenum concentration in the solution (mass%), M １Ｐ is the concentration of phosphorus in the solution (mass%), M １Ｖ is the concentration of vanadium in the solution (mass%), M ２Ｍｏ is the proportion of molybdenum in the solid content (mass%), M ２Ｐ is the proportion of phosphorus in the solid content (mass%), M ２Ｖ is the proportion of vanadium in the solid content (mass %).

[0055] <Step (iii)> In step (iii), the A2 liquid obtained in step (ii) is dried to obtain dried particles that are catalyst precursors. Drying can be performed by spray drying or drum drying, with spray drying being preferred. Spray drying can be performed using a spray dryer. Drum drying can be performed using a drum dryer. In the spray dryer, the contact method between the sprayed droplets and the hot air may be any of parallel flow, counter flow, and parallel counter flow (mixed flow).

[0056] The inlet temperature of the spray dryer is preferably 100 to 500°C. The lower limit of the inlet temperature is more preferably 200°C or higher, even more preferably 220°C or higher, and particularly preferably 240°C or higher. The upper limit of the inlet temperature is more preferably 400°C or lower, even more preferably 370°C or lower. The outlet temperature of the spray dryer is preferably 100 to 200°C, more preferably 105 to 200°C. For example, by increasing the inlet temperature or outlet temperature of the spray dryer, the solvent evaporates rapidly, making it less likely that droplets will shrink during solvent evaporation, and the pore volume and median diameter of the resulting catalyst precursor tend to be larger. By setting the inlet temperature and outlet temperature of the spray dryer within the above ranges, a catalyst precursor having a specified pore volume and preferred median diameter can be easily obtained. Spray drying is preferably performed so that the moisture content of the resulting catalyst precursor is 0.1 to 4.5% by mass.

[0057] The catalyst precursor can be produced as described above. Although the catalyst precursor may have catalytic activity, it is preferable to use a catalyst produced by molding and / or calcining, which will be described later, from the viewpoint of the yield of the α,β-unsaturated carboxylic acid.

[0058] [Method for producing catalyst] The method for producing a catalyst according to this embodiment is a method for producing a catalyst used in producing an α,β-unsaturated carboxylic acid by oxidizing an α,β-unsaturated aldehyde, and comprises molding and / or calcining the catalyst precursor according to this embodiment. Note that "molding and / or calcining" means that only molding may be performed, only calcination may be performed, or both molding and calcination may be performed.

[0059] <Shaping of catalyst precursor> The method for shaping the catalyst precursor is not particularly limited, and known dry and wet shaping methods can be applied, such as tableting, press molding, pressure molding, extrusion molding, and granulation molding. The shape of the resulting molded body is not particularly limited, and examples thereof include cylindrical, ring-shaped, and spherical shapes. Furthermore, during molding, it is preferable to mold only the catalyst precursor without adding a carrier or the like to the catalyst precursor, but known additives such as graphite and talc may be added as necessary. When a carrier is used, the carrier is not particularly limited, but silica is preferred. Furthermore, molding may be performed after the calcination described below.

[0060] <Caking of catalyst precursor> The calcination can be carried out under a flow of at least one of an oxygen-containing gas such as air and an inert gas, and it is preferable to carry out the calcination under a flow of an oxygen-containing gas such as air. Here, the inert gas refers to a gas that does not reduce the catalytic activity, and examples thereof include nitrogen, carbon dioxide, helium, and argon. These may be used alone or in combination of two or more.

[0061] The calcination method is not particularly limited and may be a fluidized bed, rotary kiln, muffle furnace, tunnel calciner, etc., and an appropriate method can be selected taking into consideration the final catalyst performance, mechanical strength, moldability, production efficiency, etc.

[0062] The firing temperature (maximum temperature during firing) is preferably 200 to 700°C, with the lower limit being more preferably 320°C or higher and the upper limit being more preferably 450°C or lower.

[0063] [Catalyst Molded Body] The catalyst molded body according to this embodiment is used in producing an α,β-unsaturated carboxylic acid by oxidizing an α,β-unsaturated aldehyde, and contains a catalytic component containing phosphorus, molybdenum, and vanadium. The catalyst molded body has a pore volume of 0.01 to 0.40 mL / g, and a pore distribution curve of the catalyst molded body, in which the height of the highest peak (Peak A) present in the pore diameter range of 0.05 to 10 μm is defined as IA, and the height of the second highest peak (Peak B) is defined as IB, where IB is the height of the second highest peak (Peak B), and IB is the height of the second highest peak (Peak B), such that IB / IA is 0.160 to 0.420.

[0064] The pore volume and pore distribution of molded catalyst bodies for producing α,β-unsaturated carboxylic acids have been investigated in the past. However, it is difficult to produce molded catalyst bodies by controlling these independently, and no attempt has been made to control both the pore volume and pore distribution of the molded catalyst body. Furthermore, while increasing the pore volume of the molded catalyst body has traditionally improved the yield of α,β-unsaturated carboxylic acid, there has been a problem in that the weight of the molded catalyst body that can be packed into a reactor of a given volume decreases. As a result, the effect of increasing the pore volume of the molded catalyst body to improve the yield of α,β-unsaturated carboxylic acid could not be fully achieved.

[0065] In the present invention, as a result of investigations into the pore distribution of the molded catalyst, it was found that the above-mentioned problems can be solved by setting the IB / IA ratio within a specified range, and further that an α,β-unsaturated carboxylic acid can be produced in a particularly high yield by setting the pore volume of the molded catalyst within a specified range.

[0066] <Composition of catalyst component> The catalyst molded body according to this embodiment contains a catalyst component containing phosphorus, molybdenum, and vanadium. From the viewpoint of improving the yield of α,β-unsaturated carboxylic acid, the preferred aspects of the catalyst component with respect to the ratio of the number of phosphorus atoms to the number of molybdenum atoms and the ratio of the number of vanadium atoms to the number of molybdenum atoms are the same as the preferred aspects of the catalyst precursor according to this embodiment.

[0067] From the viewpoint of improving the yield of α,β-unsaturated carboxylic acid, the catalyst component preferably has a composition represented by the above formula (I), similar to the catalyst precursor according to this embodiment. The catalyst component may contain small amounts of elements not represented by the above formula (I). Regarding the composition represented by the above formula (I), the preferred embodiment of the catalyst component is the same as the preferred embodiment of the catalyst precursor according to this embodiment.

[0068] <Pore Volume and Pore Distribution of Catalyst Molded Body> The pore volume of the catalyst molded body according to this embodiment is 0.01 to 0.40 mL / g. A pore volume of 0.01 mL / g or more allows the raw material α,β-unsaturated aldehyde to sufficiently diffuse and interact with the surface active sites, thereby improving the reaction rate. Furthermore, the resulting α,β-unsaturated carboxylic acid also sufficiently diffuses, suppressing the reaction in which the α,β-unsaturated carboxylic acid is converted into a by-product by successive oxidation. A pore volume of 0.4 mL / g or less sufficiently increases the density of the catalyst molded body, increasing the weight of the catalyst molded body that can be packed into a reactor of a given volume, thereby improving the yield of the α,β-unsaturated carboxylic acid. The lower limit of the pore volume is preferably 0.10 mL / g or more, more preferably 0.20 mL / g or more. The upper limit of the pore volume is preferably 0.35 mL / g or less, more preferably 0.30 mL / g or less.

[0069] Examples of methods for obtaining a catalyst molded body having a pore volume within the above range include a method of producing a catalyst molded body by the production method described below, and adjusting the addition rate v (mol / h) of compound B, the temperature of liquid A1, and the stirring rotation speed of liquid A1 in step (ii), a method of adjusting the physical properties of liquid A2, a method of adjusting drying conditions in step (iii), and a method of adjusting extrusion molding conditions in step (iv).

[0070] In the catalyst molded body according to this embodiment, the IB / IA ratio is 0.160 to 0.420, where IA is the height of the highest peak (Peak A) in the pore diameter range of 0.05 to 10 μm, and IB is the height of the second highest peak (Peak B) in the pore distribution curve. A pore distribution satisfying this condition is particularly effective for the diffusion of the raw material α,β-unsaturated aldehyde and the resulting α,β-unsaturated carboxylic acid, and allows the α,β-unsaturated aldehyde and α,β-unsaturated carboxylic acid to diffuse sufficiently regardless of the pore volume. As a result, it is possible to simultaneously achieve an improvement in the yield of α,β-unsaturated carboxylic acid due to the sufficient diffusion of the α,β-unsaturated aldehyde and α,β-unsaturated carboxylic acid, and an improvement in the yield of α,β-unsaturated carboxylic acid due to the increased weight of the catalyst molded body that can be packed into a reactor of a given volume, which is presumably a significant effect. The lower limit of IB / IA is preferably 0.200 or more, and the upper limit is preferably 0.400 or less.

[0071] Furthermore, the number of peaks in the pore diameter range of 0.05 to 10 μm in the pore distribution curve is preferably 4 or less, more preferably 3 or less, and even more preferably 2. The apexes of Peak A and Peak B are preferably in the range of 0.05 μm or more, more preferably 0.08 μm or more, and even more preferably 0.10 μm or more. They are also preferably in the range of 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less. When Peak A and Peak B are in these ranges, the pore distribution is suitable for the diffusion of α,β-unsaturated aldehyde and α,β-unsaturated carboxylic acid, and the yield of α,β-unsaturated carboxylic acid is improved.

[0072] In the present invention, the pore volume and pore distribution of the catalyst molded body are measured using mercury intrusion porosimetry. The pore volume and pore distribution of the catalyst molded body can be measured using a pore distribution measuring device such as AutoPore IV-9500 (product name, manufactured by Micromeritics). In the present invention, the pore size distribution curve refers to a log differential pore volume distribution curve. The log differential pore volume distribution is a graph in which the differential pore volume is divided by the difference in common logarithm of the pore diameter, and this value is plotted against the average pore diameter for each interval. In the present invention, the apex of the peak refers to the position where the first derivative of the pore size distribution curve is 0 and the second derivative is negative. In addition, the height of the peak refers to the distance from the horizontal line where the vertical axis value is 0 to the apex of the peak.

[0073] <Specific Surface Area of ​​Catalyst Molded Body> The specific surface area of ​​the catalyst molded body according to this embodiment is 1 to 10 m ２ / g. ２ / g or more, the number of active sites that can react with the raw material α,β-unsaturated aldehyde is sufficiently increased, improving the yield of α,β-unsaturated carboxylic acid. ２ / g or less, the pore volume described below can be easily controlled within a specified range. ２ / g or more is more preferable, and 2m ２ The upper limit of the specific surface area is 8 m / g or more. ２ / g or less is more preferable, and 6m ２ / g or less is more preferable, and 4m ２ / g or less is particularly preferred.

[0074] In the present invention, the specific surface area of ​​the catalyst molded body is a value determined using a nitrogen adsorption method. The specific surface area of ​​the catalyst molded body can be calculated using, for example, a Tristar 3000 (product name, manufactured by Micrometrics) by the BET 5-point method. Methods for obtaining a catalyst molded body having a specific surface area within the above range include, for example, producing a catalyst molded body using the production method described below, and adjusting the addition rate v (mol / h) of compound B, the temperature of liquid A1, and the stirring rotation speed of liquid A1 in step (ii), or adjusting the physical properties of liquid A2.

[0075] <Shape of Catalyst Molded Body> The shape of the catalyst molded body is not particularly limited, and examples thereof include spherical, cylindrical, ring-shaped, star-shaped, and granular shapes obtained by crushing and classifying the molded body after molding. Among these, spherical, cylindrical, and ring-shaped shapes are preferred from the viewpoint of mechanical strength. The size of the molded body is not particularly limited, but for example, in the case of a spherical shape, the diameter of the sphere is preferably 0.1 to 10 mm. The lower limit of the diameter of the sphere is more preferably 0.5 mm or more, even more preferably 1 mm or more, and particularly preferably 3 mm or more. The upper limit of the diameter of the sphere is more preferably 8 mm or less, even more preferably 6 mm or less. In the case of a ring or cylindrical shape, the diameter and height of the circle at the base of the ring or cylinder are both preferably 0.1 to 10 mm. The lower limits of the diameter and height are more preferably 0.5 mm or more, even more preferably 1 mm or more, and particularly preferably 3 mm or more. The upper limits of the diameter and height are more preferably 8 mm or less, even more preferably 6 mm or less. In the case of other shapes, the length between the two most distant points in the solid body of the catalyst molded body is preferably 0.1 to 10 mm. The lower limit of the length between the two points is more preferably 0.5 mm or more, even more preferably 1 mm or more, and particularly preferably 3 mm or more. The upper limit of the length between the two points is more preferably 8 mm or less, even more preferably 6 mm or less. This improves the yield of the target product and the continuous operation period of the catalyst molded body. The catalyst molded body according to this embodiment is preferably an extrusion molded body.

[0076] [Method for Manufacturing Molded Catalyst] The molded catalyst according to this embodiment contains catalytic components including phosphorus, molybdenum, and vanadium, has a pore volume of 0.01 to 0.40 mL / g, and has a pore distribution curve in which the pore diameter is in the range of 0.05 to 10 μm, where IA is the height of the highest peak (Peak A) and IB is the height of the second highest peak (Peak B). If IB / IA is 0.160 to 0.420, the molded catalyst according to this embodiment can be manufactured according to a known method for manufacturing a molded catalyst. However, the molded catalyst according to this embodiment is preferably manufactured by the method including the above steps (i) to (iii) and the following step (iv): (iv) extrusion-molding the dried particles to obtain a molded catalyst. The method for manufacturing a molded catalyst according to this embodiment may further include a calcination step, which will be described later.

[0077] In the method for producing a molded catalyst body according to this embodiment, preferred aspects of steps (i) to (iii) are the same as the preferred aspects of the method for producing a catalyst precursor according to this embodiment.

[0078] In step (ii), satisfying formula (II) means that the rate of addition of ammonium radicals is sufficiently slow, which reduces the degree of supersaturation of the heteropolyacid ammonium salt produced upon addition of the ammonium radicals, thereby increasing the particle size of particles (primary particles) formed by nucleation growth of the heteropolyacid ammonium salt and improving the strength of dried particles produced upon drying A2 in step (iii).

[0079] Then, by extrusion-molding the high-strength dried particles in step (iv) described below, the shape of the dried particles is maintained even after molding. Therefore, two types of pores are formed in the catalyst molded body: pores in the dried particles originating from the voids between the primary particles, and pores originating from the voids between the dried particles. Usually, the pores originating from the voids between the dried particles are Peak A, and the pores in the dried particles originating from the voids between the primary particles are Peak B. By adjusting the extrusion molding conditions in step (iv) described below, the ratio of the pores in the dried particles originating from the voids between the primary particles to the pores originating from the voids between the dried particles can be adjusted, and a catalyst molded body having an IB / IA ratio within the specified range can be easily obtained.

[0080] Furthermore, as the particle size of the primary particles generated in Solution A2 increases, the particle size of the dried particles also increases. In this case, when the dried particles are extruded in step (iv) described below, the voids between the primary particles and the voids between the dried particles become pores, resulting in a larger pore diameter at the peak in the pore size distribution. By adding ammonium radicals so as to satisfy the formula (II), a molded catalyst body can be easily obtained in which the apexes of Peak A and Peak B are within a preferred range. In formula (II), v / M is 1.00h －１ More preferably, it is 0.50h or less. －１ It is even more preferable that:

[0081] The temperature of Liquid A1 when Compound B is added is preferably 90 to 99°C. If the temperature of Liquid A1 when Compound B is added is low, the degree of supersaturation of the heteropolyacid ammonium salt produced when the ammonium radical is added increases, resulting in a smaller particle size of the primary particles formed in Liquid A2 and a larger specific surface area of ​​the molded catalyst body obtained in step (iv) described below. By keeping the temperature of Liquid A1 when Compound B is added within the above range, a molded catalyst body having a desirable specific surface area can be easily obtained.

[0082] Furthermore, as the particle size of the primary particles generated in Liquid A2 decreases, the particle size of the dried particles also decreases, and when the dried particles are molded, the voids between the primary particles and the voids between the dried particles become pores, resulting in a smaller pore diameter at the peak in the pore size distribution. By setting the temperature of Liquid A1 at 90 to 99°C when Compound B is added, a catalyst molded body in which the apexes of Peak A and Peak B lie within a preferred range can be easily obtained. The lower limit of the temperature of A1 is more preferably 92°C or higher, and the upper limit is more preferably 98°C or lower.

[0083] When compound B is added, it is preferable to add liquid A1 while stirring at a rotation speed of 70 to 140 rpm. Liquid A1 can be stirred using a stirring device such as a rotary blade stirrer. By stirring liquid A1 at a rotation speed of 70 rpm or more, liquid A1 is sufficiently stirred, thereby reducing the degree of supersaturation of the heteropolyacid ammonium salt produced by the addition of ammonium radical. This improves the strength of the dried particles produced when liquid A2 is dried in step (iii), for the same reasons as described above, and makes it easy to obtain a molded catalyst having an IB / IA ratio within the specified range. Furthermore, it makes it easy to obtain a molded catalyst having the apexes of Peak A and Peak B within the preferred ranges.

[0084] Furthermore, by stirring Liquid A1 at a rotation speed of 140 rpm or less, the degree of supersaturation of the heteropolyacid ammonium salt produced when the ammonium radical is added increases, thereby reducing the particle size of the primary particles formed in Liquid A2. This makes it possible to easily obtain a catalyst molded body having a desirable specific surface area in step (iv) described below. The lower limit of the rotation speed is more preferably 100 rpm or more, and the upper limit is more preferably 130 rpm or less.

[0085] The solids concentration of the resulting A2 liquid is preferably 30% by mass or less, and more preferably 22 to 27% by mass. When A2 liquid is dried in step (iii), the portions where the solvent has evaporated from the droplets become the pores of the dried particles. By having the solids concentration of A2 liquid within the above range, the solvent component is appropriately present in A2 liquid, and dried particles having an appropriate pore volume can be easily obtained. When the dried particles are molded, a catalyst molded body having a specified pore volume can be easily obtained. It is more preferable that the lower limit of the solids concentration is 23% by mass or more and the upper limit is 26.5% by mass or less.

[0086] In Liquid A2, when the ratio of the total mass of dissolved molybdenum, phosphorus, and vanadium elements to the total mass of molybdenum, phosphorus, and vanadium elements is R, R is preferably 5 to 25 mass%, more preferably 5 to 20 mass%. This allows the dissolved components to precipitate in the voids between the primary particles in Liquid A2 when Liquid A2 is dried in step (iii), thereby appropriately filling the voids and easily producing dried particles having an appropriate pore volume. Then, by molding the dried particles, a catalyst molded body having a specified pore volume can be easily produced.

[0087] Furthermore, since the strength is improved by filling the voids in the dried particles, the shape of the dried particles is maintained even after extrusion molding in step (iv) described below. Therefore, two types of pores are formed in the catalyst molded body: pores in the dried particles derived from the voids between the primary particles, and pores derived from the voids between the dried particles. By adjusting the extrusion molding conditions in step (iv) described below, the ratio of the pores in the dried particles derived from the voids between the primary particles to the pores derived from the voids between the dried particles can be adjusted, and a catalyst molded body having an IB / IA ratio within the specified range can be easily obtained. The lower limit of R is more preferably 6% by mass or more, and the upper limit is more preferably 15% by mass or less.

[0088] In step (iii), when the drying is performed by spray drying using a spray dryer, the inlet temperature of the spray dryer is preferably 100 to 500°C. The lower limit of the inlet temperature is more preferably 200°C or higher, even more preferably 220°C or higher, and particularly preferably 240°C or higher. The upper limit of the inlet temperature is more preferably 400°C or lower, even more preferably 370°C or lower. The outlet temperature of the spray dryer is preferably 100 to 200°C, more preferably 105 to 200°C. For example, by lowering the inlet temperature or outlet temperature of the spray dryer, the solvent evaporates slowly, making it easier for droplets to shrink during solvent evaporation, which reduces the pore volume of the resulting dried particles and tends to reduce the pore volume of the catalyst molded body. By setting the inlet temperature and outlet temperature of the spray dryer within the above ranges, dried particles having a specified pore volume can be easily obtained.

[0089] Furthermore, by setting the inlet and outlet temperatures of the spray dryer at or above the above-mentioned temperatures, the strength of the dried particles is improved, and therefore, when the dried particles are extrusion-molded in step (iv) described below, the shape of the dried particles is maintained after molding. Therefore, two types of pores are formed in the catalyst molded body: pores within the dried particles originating from the voids between the primary particles, and pores originating from the voids between the dried particles. By adjusting the extrusion molding conditions in step (iv) described below, the ratio of the pores within the dried particles originating from the voids between the primary particles to the pores originating from the voids between the dried particles can be adjusted, and a catalyst molded body having an IB / IA ratio within the specified range can be easily obtained. It is preferable that the spray drying be performed so that the moisture content of the resulting dried particles is 0.1 to 4.5% by mass.

[0090] <Step (iv)> In step (iv), the dried particles obtained in step (iii) are extrusion-molded to obtain a catalyst molded body. The extrusion molding may be performed after the calcination step described below. Molding the dried particles by extrusion molding allows for easy production of a catalyst molded body having a specified pore volume and pore distribution. When a carrier is used, the carrier is not particularly limited, but silica is preferred. In extrusion molding, the dried particles may be pulverized before extrusion molding, if necessary. Depending on the properties of the dried particles, additives may be mixed with the dried particles to obtain a kneaded product, which is then extruded using an extruder. It is preferred to mix a liquid and additives with the dried particles to obtain a kneaded product, which is then extruded using an extruder. It is more preferred to mix a liquid and a binder with the dried particles to obtain a kneaded product, which is then extruded using an extruder.

[0091] (Liquid to be mixed with dried particles) The liquid to be mixed with the dried particles is not particularly limited as long as it has the function of wetting the dried particles, and examples thereof include water and alcohols having 1 to 4 carbon atoms such as methanol, ethanol, propanol, and butanol. Among these, ethanol and propanol are preferred from the viewpoints of preventing the dried particles from collapsing and easily forming pores effective for the oxidation reaction of the α,β-unsaturated aldehyde. These may be used alone or in combination of two or more.

[0092] The amount of liquid used is selected appropriately depending on the type and size of the dried particles, the type of liquid, etc., but is preferably 15 to 60 parts by mass per 100 parts by mass of the dried particles. As the amount of liquid used increases, the dried particles become less likely to collapse during extrusion molding, and the number of pores originating from the voids between the dried particles increases, tending to decrease the IB / IA ratio. By using an amount of liquid of 15 parts by mass or more per 100 parts by mass of the dried particles, a molded catalyst body having an IB / IA ratio within the specified range can be easily obtained. Furthermore, by using an amount of liquid of 60 parts by mass or less, a molded catalyst body having a small total pore volume and high strength can be easily obtained. The lower limit of the amount of liquid used per 100 parts by mass of the dried particles is more preferably 16 parts by mass or more. The upper limit is more preferably 50 parts by mass or less, even more preferably 45 parts by mass or less, and particularly preferably 35 parts by mass or less.

[0093] (Additives to be mixed with dried particles) The additives to be mixed with the dried particles are not particularly limited, and known additives such as graphite, talc, organic binders, and inorganic binders can be used. Among these, it is preferable to mix an organic binder from the viewpoint of improving moldability in extrusion molding. Examples of organic binders include polymer compounds such as polyvinyl alcohol, α-glucan derivatives, β-glucan derivatives, etc. These may be used alone or in combination of two or more.

[0094] The α-glucan derivative is a polysaccharide composed of glucose in which glucose is bonded in an α-type structure. Examples include derivatives of α1-4 glucan, α1-6 glucan, and α1-4 / 1-6 glucan. Examples of such α-glucan derivatives include amylose, glycogen, amylopectin, pullulan, dextrin, and cyclodextrin. These may be used alone or in combination of two or more.

[0095] The β-glucan derivative is a polysaccharide composed of glucose in which glucose is bonded in a β-type structure. Examples include derivatives of β1-4 glucan, β1-3 glucan, β1-6 glucan, and β1-3 / 1-6 glucan. Examples of such β-glucan derivatives include cellulose derivatives such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxybutyl methyl cellulose, and ethyl hydroxyethyl cellulose, as well as curdlan, laminaran, paramylon, callose, pachyman, and scleroglucan. These may be used alone or in combination of two or more.

[0096] The organic binder may be used unpurified or purified. However, the presence of metal impurities or ignition residues may reduce catalytic performance, so a lower content of these is preferable. The amount of organic binder used is selected appropriately depending on the type and size of the dried particles, the type of liquid, etc., but is preferably 0.05 to 15 parts by mass per 100 parts by mass of the dried particles, with a lower limit of 0.1 parts by mass or more and an upper limit of 10 parts by mass or less being more preferable. When the amount of organic binder used is 0.05 parts by mass or more, moldability in extrusion molding is improved. Furthermore, by performing the calcination step described below, the portions from which the organic binder has been removed become pores, making it easy to obtain a catalyst molded body with a specified pore volume. Furthermore, when the amount of organic binder used is 15 parts by mass or less, the organic binder can be easily removed by performing the calcination step described below, thereby suppressing adverse effects on catalytic performance.

[0097] (Mixing of dried particles with liquid and additives) The dried particles with liquid and additives are preferably mixed using a batch mixer equipped with a double-arm stirring blade, or a continuous mixer such as a reciprocating shaft mixer or a self-cleaning mixer. As the mixer, a batch mixer is preferred from the viewpoint of being able to check the state of mixing. The end point of mixing is the point when the mixture reaches a state suitable for extrusion molding, and this end point is determined by visual inspection or touch.

[0098] (Extrusion molding) In extrusion molding, the dried particles or mixture are placed in a mold and extruded under pressure to form a specific shape to obtain an extruded product. For extrusion molding, for example, a screw extruder, a plunger extruder, etc. can be used, and it is preferable to use a plunger extruder.

[0099] The extrusion pressure is preferably 0.1 to 30 MPa. By setting the extrusion pressure to 0.1 MPa or more, a molded catalyst body having a specified pore volume and high mechanical strength can be stably obtained. Furthermore, when the extrusion pressure is low, destruction of the dried material particles constituting the molded catalyst body is suppressed, and the number of pores originating from the voids between the dried material particles increases, which tends to decrease the IB / IA ratio. By setting the extrusion pressure to 30 MPa or less, a molded catalyst body having an IB / IA ratio within the specified range can be easily obtained. The lower limit of the extrusion pressure is more preferably 0.5 MPa or more, even more preferably 1 MPa or more, and particularly preferably 2 MPa or more. Furthermore, the upper limit of the extrusion pressure is more preferably 20 MPa or less, and even more preferably 15 MPa or less.

[0100] The resulting molded catalyst body may be cut to a desired size as needed. The cutting method can be selected from any known techniques, such as a method using a rotating cutting blade or a method using a reciprocating cutting blade.

[0101] When the dried particles and a liquid are mixed and extrusion-molded, it is preferable to hold the resulting catalyst molded body at a temperature of 10 to 200°C as needed to remove the liquid contained in the catalyst molded body. A temperature of 10°C or higher allows for sufficient removal of the liquid component. A temperature of 200°C or lower prevents deterioration of the catalyst molded body. The lower limit of the holding temperature is more preferably 20°C or higher. The upper limit of the holding temperature is more preferably 180°C or lower, even more preferably 150°C or lower, and particularly preferably 120°C or lower. The liquid may be removed by drying the catalyst molded body using any commonly known dryer. The operating conditions of the dryer are not particularly limited, and the catalyst molded body may be held, for example, in an air atmosphere or a nitrogen atmosphere.

[0102] The catalyst molded body obtained in step (iv) exhibits catalytic performance and can be used for producing an α,β-unsaturated carboxylic acid, but by further carrying out the calcination process described below, a catalyst molded body having a specified specific surface area, pore volume, and pore distribution curve can be easily obtained, and the yield of an α,β-unsaturated carboxylic acid is improved, which is preferable. In the present invention, the term "catalyst molded body" includes both the calcined and calcined products.

[0103] <Causing Step> In the calcination step, the dried particles obtained in step (iii) or the catalyst molded body obtained in step (iv) are calcined as needed. Calcination can be carried out under a flow of at least one of an oxygen-containing gas such as air and an inert gas, and it is preferable to perform the calcination under a flow of an oxygen-containing gas such as air. Here, the inert gas refers to a gas that does not reduce the catalytic activity, and examples thereof include nitrogen, carbon dioxide, helium, and argon. These may be used alone or in combination of two or more.

[0104] The calcination method is not particularly limited and may be a fluidized bed, rotary kiln, muffle furnace, tunnel calciner, etc., and an appropriate method can be selected taking into consideration the final catalyst performance, mechanical strength, moldability, production efficiency, etc.

[0105] The calcination temperature (maximum temperature during calcination) is preferably 200 to 700° C., more preferably a lower limit of 320° C. or more and an upper limit of 450° C. or less. In this manner, the catalyst molded body can be produced.

[0106] [Method for producing α,β-unsaturated carboxylic acid] In the method for producing α,β-unsaturated carboxylic acid according to this embodiment, an α,β-unsaturated aldehyde is oxidized using a catalyst obtained by molding and / or calcining the catalyst precursor according to this embodiment, or a molded catalyst according to this embodiment. Furthermore, in the method for producing α,β-unsaturated carboxylic acid according to this embodiment, an α,β-unsaturated aldehyde is oxidized using a catalyst obtained by molding and / or calcining the catalyst precursor produced by the method for producing a catalyst precursor according to this embodiment, or a molded catalyst produced by the method for producing a molded catalyst according to this embodiment. These methods enable the production of unsaturated carboxylic acid in high yield. From the viewpoint of product yield, the α,β-unsaturated aldehyde and the α,β-unsaturated carboxylic acid are preferably methacrolein and methacrylic acid, respectively.

[0107] The method for producing an α,β-unsaturated carboxylic acid according to this embodiment can be carried out by contacting a raw material gas containing an α,β-unsaturated aldehyde with a catalyst obtained by molding and / or calcining the catalyst precursor according to this embodiment, or a molded catalyst. A fixed-bed reactor can be used for this reaction.

[0108] The reaction can be carried out by filling a reactor with a catalyst or a shaped catalyst and supplying a raw material gas to the reactor. The catalyst layer or shaped catalyst layer may be a single layer, or multiple catalysts or shaped catalysts with different activities may be packed in multiple layers. In addition, to control the activity, the catalyst or shaped catalyst may be diluted with an inert carrier and packed.

[0109] The concentration of the α,β-unsaturated aldehyde in the raw material gas is preferably 1 to 20% by volume, more preferably 3% by volume or more in lower limit and 10% by volume or less in upper limit. The α,β-unsaturated aldehyde as the raw material may contain small amounts of impurities such as lower saturated aldehydes that do not substantially affect the reaction.

[0110] The oxygen source for the raw material gas is not particularly limited, but it is industrially advantageous to use air. Furthermore, if necessary, a gas obtained by mixing pure oxygen with air or the like can also be used. The proportion of oxygen in the raw material gas is not particularly limited, but is preferably 0.4 to 4 moles per mole of the α,β-unsaturated aldehyde, with the lower limit being more preferably 0.5 moles or more and the upper limit being 3 moles or less.

[0111] From an economical viewpoint, the raw material gas may be diluted with an inert gas such as nitrogen or carbon dioxide. Furthermore, water vapor may be added to the raw material gas. By carrying out the reaction in the presence of water vapor, an α,β-unsaturated carboxylic acid can be obtained in a higher yield. The concentration of water vapor in the raw material gas is preferably 0.1 to 50% by volume, with the lower limit being 1% by volume or more and the upper limit being more preferably 40% by volume.

[0112] The contact time between the raw material gas and the catalyst for producing an α,β-unsaturated carboxylic acid or the molded catalyst is preferably 0.5 to 15 seconds, more preferably a lower limit of 1.5 seconds or more and an upper limit of 10 seconds or less. The reaction pressure is preferably 0 to 1 MPaG. However, "G" represents gauge pressure, and 0 MPaG means that the reaction pressure is atmospheric pressure. The reaction temperature is preferably 200 to 450°C, more preferably a lower limit of 250°C or more and an upper limit of 400°C or less.

[0113] [Method for Producing α,β-Unsaturated Carboxylic Acid Ester] In the method for producing an α,β-unsaturated carboxylic acid ester according to this embodiment, the α,β-unsaturated carboxylic acid produced by the production method according to this embodiment is esterified. That is, the method for producing an α,β-unsaturated carboxylic acid ester according to this embodiment includes the steps of producing an α,β-unsaturated carboxylic acid by the method according to this embodiment and esterifying the α,β-unsaturated carboxylic acid.

[0114] The alcohol to be reacted with the α,β-unsaturated carboxylic acid is not particularly limited, and examples thereof include methanol, ethanol, n-propanol, isopropanol, n-butanol, and isobutanol. Examples of the resulting α,β-unsaturated carboxylic acid ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, and isobutyl (meth)acrylate. The esterification reaction can be carried out in the presence of an acidic catalyst such as a sulfonic acid-type cation exchange resin. The temperature during the esterification reaction is preferably 50 to 200°C.

[0115] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these examples. In addition, "parts" means "parts by mass."

[0116] (Composition ratio of catalyst precursor and composition ratio of catalyst component) The molar ratio of each component was determined by analyzing the components obtained by dissolving the catalyst precursor or the catalyst molded body in ammonia water using an ICP optical emission analyzer Optima 8300 ICP-OES Spectrometer (product name, manufactured by PerkinElmer). The molar ratio of ammonium radicals was determined by analyzing the catalyst precursor or the catalyst molded body by the Kjeldahl method.

[0117] (Specific Surface Area of ​​Catalyst Molded Body) The specific surface area of ​​the catalyst molded body was measured using a nitrogen adsorption measurement device Tristar 3000 (product name, manufactured by Micrometrics) on 1.5 g of the catalyst molded body pretreated at 200°C, and calculated by the BET 5-point method.

[0118] (Pore Volume of Catalyst Precursor) The pore volume of the catalyst precursor was measured under the following conditions using a mercury intrusion pore distribution analyzer AutoPore IV-9500 (product name, manufactured by Micrometrics) and calculated from the volume of pores with a pore diameter of 0.5 μm or less. Measurement sample amount: 1.5 g Sample pretreatment: heating at 90° C. for 12 hours Cell volume: 1.131 mL Initial evacuation: 5 minutes at 50 μmHg Equilibration waiting time: 5 minutes Measurement pressure range: 0.0038 to 207 MPa Measurement pore diameter range: 0.006 to 329 μm

[0119] (Pore volume and pore distribution of catalyst molded body) The pore volume and pore distribution of the catalyst molded body were measured using a mercury intrusion porosimetry pore distribution measuring device AutoPore IV-9500 (product name, manufactured by Micrometrics) under the following conditions: Measurement sample: 10 catalyst molded bodies Cell volume: 1.131 mL Initial vacuum: 50 μmHg for 5 minutes Equilibration waiting time: 5 minutes Measurement pressure range: 0.0038 to 207 MPa Measurement pore diameter range: 0.006 to 329 μm

[0120] The physical properties of the mercury used in the measurements using the mercury intrusion porosimetry apparatus were as follows: Mercury contact angle: 130°, Mercury surface tension: 485 dynes / cm, Mercury density: 13.5335 g / mL

[0121] (Median diameter of catalyst precursor) The median diameter of the catalyst precursor was measured using a laser diffraction wet particle size distribution analyzer LA-700 (product name, manufactured by Horiba, Ltd.) under the following conditions: Dispersion medium: ethanol Refractive index setting: 1.8

[0122] (Analysis of Keggin-type heteropolyacid in catalyst precursor) The presence or absence of Keggin-type heteropolyacid in the catalyst precursor was determined by infrared absorption analysis using a NICOLET6700FT-IR (product name, manufactured by Thermo Electron Corporation). FT-IR measurement was performed by the transmission method. First, KBr was formed into pellets using a tablet forming machine, and background measurement was performed. Next, the catalyst was diluted and mixed with KBr so that the catalyst concentration was 0.5 to 1 mass%, and similarly formed into pellets and measured. The obtained infrared absorption spectrum was plotted with absorbance on the vertical axis and wavenumber on the horizontal axis, with a 1200 cm －１ The baseline was corrected horizontally so that the absorbance at 1065 cm was 0. It is known that in the Keggin structure, four characteristic peaks are observed, which are attributed to the vibrations of P-O, M-O, M-O-M between octahedra, and M-O-M (M = Mo, V, etc.) within the octahedron. －１ , 965 cm －１ , 870 cm －１ , 790 cm －１When all of these peaks were observed in the obtained infrared absorption spectrum, it was determined that the Keggin structure was present.

[0123] (Analysis of raw material gas and product) The raw material gas and product were analyzed using gas chromatography (apparatus: GC-2014 manufactured by Shimadzu Corporation, column: DB-FFAP manufactured by J&W, 30 m x 0.32 mm, film thickness 1.0 μm). The yield of produced methacrylic acid was calculated using the following formula: Yield of methacrylic acid (%) = (N2 / N1) x 100 Here, N1 is the number of moles of methacrolein supplied, and N2 is the number of moles of produced methacrylic acid.

[0124] [Catalyst Precursor] Example 1-1 To 400 parts of 25°C pure water as a solvent, 100 parts of molybdenum trioxide, 7.5 parts of ammonium metavanadate, 11.4 parts of an 85% by mass aqueous phosphoric acid solution, and 7.0 parts of copper (II) nitrate trihydrate were added. The resulting slurry was heated to 95°C with stirring, and stirred for 3 hours while maintaining the liquid temperature at 95°C. Next, while maintaining the liquid temperature at 95°C and stirring, a solution obtained by dissolving 15.7 parts of cesium hydrogen carbonate in 20 parts of pure water was added, and the mixture was stirred for 15 minutes to obtain Solution A1.

[0125] Next, while maintaining the temperature of Liquid A1 at 95°C and stirring at 110 rpm using a rotary blade stirrer, a solution of 15.0 parts of ammonium carbonate dissolved in 20 parts of pure water was added. The addition took 105.7 minutes. The temperature and v / M of Liquid A1 at this time are shown in Table 1. After the addition was completed, the liquid temperature was maintained at 95°C and stirring was continued for an additional 15 minutes to obtain Liquid A2. The pH, solids concentration, and R of Liquid A2 are shown in Table 1.

[0126] The obtained solution A2 was spray-dried at a dryer inlet temperature of 300°C to obtain a catalyst precursor. The elemental composition of the catalyst precursor other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ (NH ４ ) ５．７ The catalyst precursor contained a Keggin-type heteropolyacid. The pore volume, median diameter and bulk density of the catalyst precursor are shown in Table 1.

[0127] 100 parts of the catalyst precursor were mixed with 5 parts of hydroxypropyl cellulose, 4 parts of pure water, and 16 parts of ethanol, and kneaded until a clay-like mixture was obtained. The mixture was extruded using an extrusion molding machine at an extrusion pressure of 10 MPa to form a cylindrical shape with a diameter of 5.5 mm and a height of 5 mm, and then dried in an air stream at 25°C for 12 hours to obtain a molded product.

[0128] The resulting molded body was calcined in an air atmosphere at 380°C for 2 hours to obtain a catalyst. The resulting catalyst was packed into a reaction tube to form a catalyst layer, and an oxidation reaction of methacrolein was carried out under the following conditions. The results are shown in Table 1.

[0129] Raw material gas composition: methacrolein 5% by volume, oxygen 10% by volume, water vapor 30% by volume, and nitrogen 55% by volume. Reaction temperature: 285°C. Contact time between raw material gas and catalyst: 3.6 seconds.

[0130] Example 1-2 A1 solution was obtained in the same manner as in Example 1-1. Next, the temperature of the A1 solution was maintained at 95°C, and a solution of 12.3 parts of ammonium carbonate dissolved in 20 parts of pure water was added while stirring at 110 rpm using a rotary blade stirrer. The addition took 86.6 minutes. The temperature and v / M of the A1 solution at this time are shown in Table 1. After the addition was completed, the solution was stirred for an additional 15 minutes while maintaining the liquid temperature at 95°C, to obtain A2 solution. The pH, solids concentration, and R of the A2 solution are shown in Table 1.

[0131] The resulting A2 solution was dried in the same manner as in Example 1-1 to obtain a catalyst precursor. The elemental composition of the catalyst precursor other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ (NH ４ ) ４．９ The catalyst precursor contained a Keggin-type heteropolyacid. The pore volume, median diameter and bulk density of the catalyst precursor are shown in Table 1.

[0132] The obtained catalyst precursor was used to carry out molding and calcination in the same manner as in Example 1-1. The obtained catalyst was packed into a reaction tube to form a catalyst layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 1-1. The results are shown in Table 1.

[0133] Example 1-3: A2 solution was obtained in the same manner as in Example 1-1. The obtained A2 solution was dried in the same manner as in Example 1-1 and sieved using a sieve with a mesh size of 15 μm. The material that fell through the sieve was used as a catalyst precursor. The elemental composition of the catalyst precursor other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ (NH ４ ) ５．７ The catalyst precursor contained a Keggin-type heteropolyacid. The pore volume, median diameter and bulk density of the catalyst precursor are shown in Table 1.

[0134] The obtained catalyst precursor was used to carry out molding and calcination in the same manner as in Example 1-1. The obtained catalyst was packed into a reaction tube to form a catalyst layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 1-1. The results are shown in Table 1.

[0135] Example 1-4 A1 solution was obtained in the same manner as in Example 1-1, except that 13.5 parts of cesium carbonate was used instead of 15.7 parts of cesium hydrogen carbonate. Then, A2 solution was obtained using this A1 solution in the same manner as in Example 1-1. The pH, solids concentration, and R of the A2 solution are shown in Table 1.

[0136] The obtained solution A2 was spray-dried at a dryer inlet temperature of 250°C to obtain a catalyst precursor. The elemental composition of the catalyst precursor other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ (NH ４ ) ５．７ The catalyst precursor contained a Keggin-type heteropolyacid. The pore volume, median diameter and bulk density of the catalyst precursor are shown in Table 1.

[0137] The obtained catalyst precursor was used to carry out molding and calcination in the same manner as in Example 1-1. The obtained catalyst was packed into a reaction tube to form a catalyst layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 1-1. The results are shown in Table 1.

[0138] Example 1-5: A1 solution was obtained in the same manner as in Example 1-1. Next, A2 solution was obtained in the same manner as in Example 1-1, except that it took 21.2 minutes to add a solution prepared by dissolving 15.0 parts of ammonium carbonate in 20 parts of pure water. The v / M, pH, solids concentration, and R of the A2 solution at this time are shown in Table 1.

[0139] The resulting A2 solution was dried in the same manner as in Example 1-1 to obtain a catalyst precursor. The elemental composition of the catalyst precursor other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ (NH ４ ) １．９ The catalyst precursor contained a Keggin-type heteropolyacid. The pore volume, median diameter and bulk density of the catalyst precursor are shown in Table 1.

[0140] The obtained catalyst precursor was used to carry out molding and calcination in the same manner as in Example 1-1. The obtained catalyst was packed into a reaction tube to form a catalyst layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 1-1. The results are shown in Table 1.

[0141] Comparative Example 1-1 100 parts of molybdenum trioxide, 7.5 parts of ammonium metavanadate, and 7.0 parts of copper (II) nitrate trihydrate were added to 400 parts of pure water at 25° C. as a solvent. The resulting slurry was heated to 95° C. with stirring, and stirred for 3 hours while maintaining the liquid temperature at 95° C. Next, the liquid temperature was lowered to 50° C., and while stirring while maintaining the liquid temperature at 50° C., a solution prepared by dissolving 15.7 parts of cesium hydrogen carbonate in 20 parts of pure water was added, and the mixture was stirred for 15 minutes to obtain Liquid A1′.

[0142] Next, while maintaining the temperature of Solution A1' at 50°C and stirring at 110 rpm using a rotary blade stirrer, a solution of 15.8 parts of ammonium nitrate dissolved in 20 parts of pure water was added. The addition took 6.8 minutes. The temperature and v / M of Solution A1' at this time are shown in Table 1. After completion of the addition, the solution was stirred for an additional 15 minutes while maintaining the liquid temperature at 95°C. 11.4 parts of an 85% by mass aqueous solution of phosphoric acid was mixed with the resulting slurry and stirred for 15 minutes to obtain Solution A2'. The pH, solids concentration, and R of Solution A2' are shown in Table 1.

[0143] The resulting A2' solution was dried in the same manner as in Example 1-1 to obtain a catalyst precursor. The elemental composition of the catalyst precursor other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ (NH ４ ) ４．５ The catalyst precursor contained a Keggin-type heteropolyacid. The pore volume, median diameter and bulk density of the catalyst precursor are shown in Table 1.

[0144] The obtained catalyst precursor was used to carry out molding and calcination in the same manner as in Example 1-1. The obtained catalyst was packed into a reaction tube to form a catalyst layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 1-1. The results are shown in Table 1.

[0145] Comparative Example 1-2: A solution A1' was obtained in the same manner as in Comparative Example 1-1, except that 200 parts of pure water at 25°C was used as the solvent. Then, using this solution A1', a solution A2' was obtained in the same manner as in Comparative Example 1-1. The pH, solids concentration, and R of the solution A2' are shown in Table 1.

[0146] The resulting A2' solution was dried in the same manner as in Example 1-1 to obtain a catalyst precursor. The elemental composition of the catalyst precursor other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ (NH ４ ) ４．５ The catalyst precursor contained a Keggin-type heteropolyacid. The pore volume, median diameter and bulk density of the catalyst precursor are shown in Table 1.

[0147] The obtained catalyst precursor was used to carry out molding and calcination in the same manner as in Example 1-1. The obtained catalyst was packed into a reaction tube to form a catalyst layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 1-1. The results are shown in Table 1.

[0148] Comparative Example 1-3: Solution A1 was obtained in the same manner as in Example 1-1. Solution A2' was then obtained in the same manner as in Example 1-1, except that it took 184.0 minutes to add a solution of 15.0 parts ammonium carbonate dissolved in 20 parts pure water. The v / M, pH, solids concentration, and R of Solution A2' at this time are shown in Table 1.

[0149] The resulting solution A2' was dried in the same manner as in Example 1-1 to obtain a catalyst precursor. The elemental composition of the catalyst precursor other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ (NH ４ ) ２．０ The catalyst precursor contained a Keggin-type heteropolyacid. The pore volume, median diameter and bulk density of the catalyst precursor are shown in Table 1.

[0150] The obtained catalyst precursor was used to carry out molding and calcination in the same manner as in Example 1-1. The obtained catalyst was packed into a reaction tube to form a catalyst layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 1-1. The results are shown in Table 1.

[0151]

[0152] As shown in Table 1, Examples 1-1 to 1-5 using catalyst precursors having pore volumes within the specified range showed higher methacrylic acid yields than the comparative examples. Note that methacrylic acid esters can be obtained by esterifying the methacrylic acid obtained in Examples 1-1 to 1-5.

[0153] [Catalyst Molded Body] Example 2-1 To 400 parts of 25°C pure water as a solvent, 100 parts of molybdenum trioxide, 7.5 parts of ammonium metavanadate, 11.4 parts of an 85 mass% aqueous phosphoric acid solution, and 7.0 parts of copper (II) nitrate trihydrate were added. The resulting slurry was heated to 95°C with stirring, and stirred for 3 hours while maintaining the liquid temperature at 95°C. Next, while maintaining the liquid temperature at 95°C and stirring, a solution obtained by dissolving 15.7 parts of cesium hydrogen carbonate in 20 parts of pure water was added, and the mixture was stirred for 15 minutes to obtain Solution A1.

[0154] Next, while maintaining the temperature of Liquid A1 at 95°C and stirring at 110 rpm using a rotary blade stirrer, a solution of 15.0 parts of ammonium carbonate dissolved in 20 parts of pure water was added. The addition took 105.7 minutes. The temperature and v / M of Liquid A1 at this time are shown in Table 2. After completion of the addition, the liquid temperature was maintained at 95°C and stirring was continued for an additional 15 minutes to obtain Liquid A2. The pH, solids concentration, and R of Liquid A2 are shown in Table 2.

[0155] The obtained A2 liquid was spray-dried at a dryer inlet temperature of 300°C to obtain dried particles. Next, 100 parts of the obtained dried particles were mixed with 5 parts of hydroxypropyl cellulose, 4 parts of pure water, and 16 parts of ethanol, and kneaded until a clay-like mixture was obtained. The mixture was extruded using an extrusion molding machine at an extrusion pressure of 10 MPa and formed into a cylindrical shape with a diameter of 5.5 mm and a height of 5 mm. This was dried at 25°C for 12 hours under air flow, and then calcined at 380°C for 2 hours under an air atmosphere to obtain a catalyst molded body. The elemental composition of the catalyst molded body other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ The molar ratio of ammonium radicals was 1 or less. The pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA ratio in the pore distribution curve of the catalyst molded body are shown in Table 2.

[0156] The resulting molded catalyst was then packed into a reaction tube to form a catalyst molded layer, and an oxidation reaction of methacrolein was carried out under the following conditions. The results are shown in Table 2.

[0157] Raw material gas composition: methacrolein 5% by volume, oxygen 10% by volume, water vapor 30% by volume, and nitrogen 55% by volume. Reaction temperature: 285°C. Contact time between raw material gas and catalyst molded body: 3.6 seconds.

[0158] Example 2-2 A1 solution was obtained in the same manner as in Example 2-1. Next, the temperature of the A1 solution was maintained at 95°C, and a solution of 12.3 parts of ammonium carbonate dissolved in 20 parts of pure water was added while stirring at 110 rpm using a rotary blade stirrer. The addition took 86.6 minutes. The temperature and v / M of the A1 solution at this time are shown in Table 2. After the addition was completed, the solution was stirred for an additional 15 minutes while maintaining the liquid temperature at 95°C, to obtain A2 solution. The pH, solids concentration, and R of the A2 solution are shown in Table 2.

[0159] The obtained A2 solution was spray-dried at the same dryer inlet temperature as in Example 2-1 to obtain dried particles. The obtained dried particles were then molded, dried, and calcined in the same manner as in Example 2-1 to obtain a molded catalyst body. The elemental composition of the molded catalyst body other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ The molar ratio of ammonium radicals was 1 or less. The pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA ratio in the pore distribution curve of the catalyst molded body are shown in Table 2.

[0160] The obtained molded catalyst was then packed into a reaction tube to form a catalyst molded body layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 2-1. The results are shown in Table 2.

[0161] Example 2-3 A2 solution was obtained by the same method as in Example 2-1. The obtained A2 solution was spray-dried at the same dryer inlet temperature as in Example 2-1, and sieved using a sieve with a mesh size of 15 μm. The particles that fell under the sieve were used as dried particles. The obtained dried particles were then molded, dried, and calcined by the same method as in Example 2-1 to obtain a molded catalyst body. The elemental composition of the molded catalyst body other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４The molar ratio of ammonium radicals was 1 or less. The pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA ratio in the pore distribution curve of the catalyst molded body are shown in Table 2.

[0162] The obtained molded catalyst was then packed into a reaction tube to form a catalyst molded body layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 2-1. The results are shown in Table 2.

[0163] Example 2-4 A1 solution was obtained in the same manner as in Example 2-1, except that 13.5 parts of cesium carbonate was used instead of 15.7 parts of cesium bicarbonate. Then, A2 solution was obtained in the same manner as in Example 2-1 using this A1 solution. The pH, solids concentration, and R of the A2 solution are shown in Table 2.

[0164] The obtained A2 solution was spray-dried at a dryer inlet temperature of 250°C to obtain dried particles. The obtained dried particles were then molded, dried, and calcined in the same manner as in Example 2-1 to obtain a molded catalyst body. The elemental composition of the molded catalyst body other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ The molar ratio of ammonium radicals was 1 or less. The pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA ratio in the pore distribution curve of the catalyst molded body are shown in Table 2.

[0165] The obtained molded catalyst was then packed into a reaction tube to form a catalyst molded body layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 2-1. The results are shown in Table 2.

[0166] Example 2-5: Solution A1 was prepared in the same manner as in Example 2-1. Solution A2 was then prepared in the same manner as in Example 2-1, except that 21.2 minutes were required to add a solution prepared by dissolving 15.0 parts of ammonium carbonate in 20 parts of pure water. The v / M ratio, pH, solids concentration, and R of solution A2 at this time are shown in Table 2.

[0167] The obtained A2 solution was dried in the same manner as in Example 2-1 to obtain dried particles. The obtained dried particles were then molded, dried, and fired in the same manner as in Example 2-1 to obtain a molded catalyst body. The elemental composition of the molded catalyst body other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ The molar ratio of ammonium radicals was 1 or less. The pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA ratio in the pore distribution curve of the catalyst molded body are shown in Table 2.

[0168] The obtained molded catalyst was then packed into a reaction tube to form a catalyst molded body layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 2-1. The results are shown in Table 2.

[0169] Comparative Example 2-1 100 parts of molybdenum trioxide, 7.5 parts of ammonium metavanadate, and 7.0 parts of copper (II) nitrate trihydrate were added to 400 parts of pure water at 25° C. as a solvent. The resulting slurry was heated to 95° C. with stirring, and stirred for 3 hours while maintaining the liquid temperature at 95° C. Next, the liquid temperature was lowered to 50° C., and while maintaining the liquid temperature at 50° C., a solution prepared by dissolving 15.7 parts of cesium hydrogen carbonate in 20 parts of pure water was added and stirred for 15 minutes to obtain Liquid A1′.

[0170] Next, while maintaining the temperature of Solution A1' at 50°C and stirring at 110 rpm using a rotary blade stirrer, a solution of 15.8 parts of ammonium nitrate dissolved in 20 parts of pure water was added. The addition took 6.8 minutes. The temperature and v / M of Solution A1' at this time are shown in Table 2. After completion of the addition, the solution was stirred for an additional 15 minutes while maintaining the liquid temperature at 95°C. 11.4 parts of an 85% by mass aqueous solution of phosphoric acid was mixed with the resulting slurry and stirred for 15 minutes to obtain Solution A2'. The pH, solids concentration, and R of Solution A2' are shown in Table 2.

[0171] The obtained A2' solution was spray-dried at the same dryer inlet temperature as in Example 2-1 to obtain dried particles. The obtained dried particles were then molded, dried, and calcined in the same manner as in Example 2-1 to obtain a molded catalyst body. The elemental composition of the molded catalyst body other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ and the molar ratio of ammonium radicals was 1 or less. In addition, the pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA in the pore distribution curve of the catalyst molded body are shown in Table 2. Next, the obtained catalyst molded body was packed into a reaction tube to form a catalyst molded body layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 2-1. The results are shown in Table 2.

[0172] Comparative Example 2-2 A1' solution was obtained in the same manner as in Comparative Example 2-1, except that 200 parts of 25°C pure water was used as the solvent. Then, using this A1' solution, A2' solution was obtained in the same manner as in Comparative Example 2-1. The pH, solids concentration, and R of this A2' solution are shown in Table 2. The obtained A2' solution was spray-dried at the same dryer inlet temperature as in Example 2-1, to obtain dried particles.

[0173] Next, the obtained dried particles were molded, dried, and calcined in the same manner as in Example 2-1 to obtain a catalyst molded body. １２ P １．７ V １．１ Cu ０．５ Cs １．４ and the molar ratio of ammonium radicals was 1 or less. In addition, the pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA in the pore distribution curve of the catalyst molded body are shown in Table 2. Next, the obtained catalyst molded body was packed into a reaction tube to form a catalyst molded body layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 2-1. The results are shown in Table 2.

[0174] Comparative Example 2-3 A1 solution was obtained in the same manner as in Example 2-1. Next, the temperature of the A1 solution was maintained at 95°C, and a solution of 15.0 parts of ammonium carbonate dissolved in 20 parts of pure water was added while stirring at 110 rpm using a rotary blade stirrer. The addition took 105.7 minutes. The temperature and v / M of the A1 solution at this time are shown in Table 2. After the addition was completed, the solution was stirred for 15 minutes while maintaining the solution temperature at 95°C, and then heated to 100°C. The solution was then stirred for 40 minutes while maintaining the solution temperature at 100°C, to obtain A2 solution. The pH, solids concentration, and R of the A2 solution are shown in Table 2.

[0175] The obtained A2 solution was dried at 140°C using a drum dryer to obtain dried particles. The obtained dried particles were then molded, dried, and calcined in the same manner as in Example 2-1 to obtain a molded catalyst body. The elemental composition of the molded catalyst body other than oxygen was Mo. １２ P １．７ V １．１ Cu ０．５ Cs １．４ and the molar ratio of ammonium radicals was 1 or less. In addition, the pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA in the pore distribution curve of the catalyst molded body are shown in Table 2. Next, the obtained catalyst molded body was packed into a reaction tube to form a catalyst molded body layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 2-1. The results are shown in Table 2.

[0176] Comparative Example 2-4 Solution A1 was obtained in the same manner as in Example 2-1, except that a solution of 15.7 parts of cesium hydrogen carbonate dissolved in 20 parts of pure water was mixed while stirring and maintaining the liquid temperature at 50°C. Solution A2' was then obtained in the same manner as in Example 2-1, except that 184.0 minutes was required to add a solution of 15.0 parts of ammonium carbonate dissolved in 20 parts of pure water. The v / M, pH, solids concentration, and R of Solution A2' at this time are shown in Table 2.

[0177] The obtained A2' solution was dried in the same manner as in Example 2-1 to obtain dried particles. The obtained dried particles were then molded, dried, and calcined in the same manner as in Example 2-1 to obtain a molded catalyst body. The elemental composition of the molded catalyst body other than oxygen was Mo.１２ P １．７ V １．１ Cu ０．５ Cs １．４ The molar ratio of ammonium radicals was 1 or less. The pore distribution curve had two peaks in the pore diameter range of 0.05 to 10 μm. The specific surface area, pore volume, and IB / IA ratio in the pore distribution curve of the catalyst molded body are shown in Table 2.

[0178] The obtained molded catalyst was then packed into a reaction tube to form a catalyst molded body layer, and an oxidation reaction of methacrolein was carried out in the same manner as in Example 2-1. The results are shown in Table 2.

[0179]

[0180] As shown in Table 2, Examples 2-1 to 2-5, in which the pore volume of the catalyst molded body and the IB / IA in the pore distribution curve were within the specified range, showed a higher methacrylic acid yield than the comparative example. Note that methacrylic acid esters can be obtained by esterifying the methacrylic acid obtained in Examples 2-1 to 2-5.

[0181] According to the present invention, it is possible to provide a catalyst precursor and a molded catalyst body that can be used to produce a catalyst that can produce an α,β-unsaturated carboxylic acid in high yield.

Claims

DEPCT681. A catalyst precursor composed of Keggin-type heteropoly acids used for the production of alpha-beta unsaturated carboxylic acids by oxidation of alpha-beta unsaturated aldehydes, where the catalyst precursor has a pore volume of 0.005 to 0.15 ml / g.

2. A catalyst precursor according to claim 1 with a median density of 1 to 50 µm.

3. A catalyst precursor according to claim 2 with a median diameter of 5 to 40 µm.

4. A catalyst precursor according to claim 1 with a pore volume of 0.01 to 0.10 ml / g.

5. A catalyst precursor according to claim 1 with a bulk density of 1.15 to 1.6 kg / L. 6.The precursor catalyst according to claim 1 has an element represented by the following formula (I):PaMobVcCudAeEfGg(NH4)hOi(I) (where P,Mo,V,Cu,NH4, and O represent phosphorus, molybdenum, vanadium, copper, ammonium radicals, and oxygen, respectively; A represents at least one element chosen from the group comprising antimony, bismuth, arsenic, germanium, tellurium, selenium, silicon, and tungsten; E represents at least one element chosen from the group comprising iron. Zinc, chromium, tannalum, cobalt, nickel, manganese, titanium, niobium, and serum; G represents at least one element chosen from the group comprising lithium, sodium, potassium, rubidium, and cesium; and a through i each represent the molar ratio of each component, corresponding to b=12, a=0.5 to 3, C=0.01 to 3, d=0.01 to 2, e=0 to 3, f=0 to 3, g=0.01 to 3, and h=1 to 30, with i being the preferred molar ratio of oxygen to match the valence of each element)7.A molded catalyst product incorporating a catalyst component containing phosphorus, molybdenum, and vanadium is used for the production of alpha-beta unsaturated carboxylic acids by the oxidation of alpha-beta unsaturated aldehydes. The molded catalyst product has a pore volume of 0.01 to 0.40 mL / g, and the pore distribution curve of the molded catalyst product shows the height of the highest peak (peak A) and the second highest peak (peak B), peaks that are within the range of diameters. Pore ​​size 0.05 to 10 µm, specified as IA and IB respectively, IB / IA ratio is 0.160 to 0.4208. Catalyst product molded according to claim 7 where the IB / IA ratio is 0.200 to 0.4009. Catalyst product molded according to claim 7 with a specific surface area of ​​1 to 10 m² / g10. Catalyst product molded according to claim 9 where the specific surface area is 1.5 to 8 m² / g11. Catalyst product molded according to claim 7 where the pore volume is 0.10 to 0.35 mL / g12.Catalyst product formed according to claim 7 where the vertices A and B have a pore diameter range of 0.08 to 8 micrometers.

13. Catalyst product formed according to claim 7 which is an extruded material.

14. Method of fabrication of the catalyst precursor according to claim 1 which consists of: (i) a step of obtaining a solution or viscous solution (liquid A1) containing phosphorus, molybdenum, and vanadium. (ii) the step of adding a raw compound containing ammonium radicals (compound B) to liquid A1 to obtain a concentrated solution with a pH of 3 or lower (liquid A2), and (iii) the step of drying liquid A2 to obtain dry particles in which in step (ii) compound B was added, whereby the subsequent formula (II) is made consistent: V / M = 0.10 to 1.80(II) (where M represents the number of moles (mol) of molybdenum added to liquid A1, and v represents the rate of ammonium radical addition (mol / hour))15.Methods of producing a molded catalyst product from a catalyst precursor produced by the method of claim 14, which includes (iv) a step of forming by extrusion of dry particles to obtain the molded catalyst product.

16. Methods of producing the catalyst, which include the calcination of any one of the catalyst precursors under claims 1 to 6, or a catalyst precursor produced by the method of claim 14.17.The method of producing the molded catalyst product according to claim 7 consists of: (i) a step of obtaining a solution or concentrate (liquid A1) containing phosphorus, molybdenum, and vanadium; (ii) a step of adding a raw material compound containing ammonium radicals (compound B) to liquid A1 to obtain a concentrate with a pH of 3 or lower (liquid A2); (iii) a step of drying liquid A2 to obtain dry particles; and (iv) a step of extrusion molding of the dry particles to obtain the molded catalyst product in which in step (ii) compound B is added, where the subsequent formula (II) is made to: v / M=0.10 to 1.80(II) (where M represents the number of moles (mol) of molybdenum incorporated into liquid A1, and v represents the rate of ammonium radical addition (mol / hour).

18. The method of producing the molded catalyst product according to claim 15 or 17 where liquid A2 has a solid concentration of 30% by mass or lower.19.Method of producing the catalyst product molded according to claim 15 or 17 in which in liquid A2 when the ratio of the total mass of dissolved molybdenum, phosphorus, and vanadium for the total mass of molybdenum, phosphorus, and vanadium is specified as R, R is 5 to 25% by mass20. Method of producing the catalyst product molded according to claim 15 or 17 in which in step (ii), compound B is added while stirring liquid A1 at a temperature of 90 to 99 degrees Celsius at a rotation speed of 70 to 140 rpm21. Method of request 22. Method of manufacturing of molded catalyst products according to claim 15 or 17 in which step (iii)A2 the liquid is dried by spraying.

23. Method of manufacturing of molded catalyst products according to claim 15 or 17 in which step (iv) consists of subsequent steps (iv-1) and (iv-2): (iv-1) step of mixing dry particles with liquid and binder to obtain kneaded product and (iv-2) step of extrusion molding of the kneaded product using an extruder to obtain molded catalyst product.Method of producing molded catalyst products according to claim 22 in which in step (iv-1) 15 to 60 parts by mass of liquid and 0.05 to 15 parts by mass of coagulant are mixed for 100 parts by mass of dry particles.

24. Method of producing molded catalyst products according to claim 22 in which in step (iv-2) extrusion molding is performed at an extrusion pressure of 0.1 to 30 megapascals.

25. Method of producing unsaturated alpha, beta carboxylic acids, a method which includes by oxidation of alpha,beta unsaturated aldehydes using a catalyst obtained by forming and / or calcining of the catalyst precursor according to one of the claims 1 to 6, or the catalyst product formed according to one of the claims 7 to 13.

26. Method of production of esters of alpha,beta unsaturated carboxylic acids, a method which includes the formation of alpha,beta unsaturated carboxylic acid esters produced by the method according to claim 25;

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