Method for producing catalysts for unsaturated carboxylic acids

Abstract

The objective is to provide a catalyst that, when used in the gas-phase catalytic oxidation of unsaturated aldehydes with an oxygen-containing gas to synthesize the corresponding unsaturated carboxylic acids, exhibits excellent conversion rates of raw materials, high selectivity for the target product, high yield production, and improved mechanical strength, even under conditions of high load on the catalyst. [Solution] A method for producing a catalyst for unsaturated carboxylic acid, comprising a molding step in which a carrier is introduced into a granulator, then a binder A which is a second binder is introduced, and then a powder containing catalyst component elements and a second binder B which is introduced, and the powder containing the catalyst component elements is supported on the carrier to form a catalyst precursor, wherein the catalyst component elements include molybdenum (Mo), vanadium (V), and copper (Cu), and the ratio of the introduction rate of binder A to the introduction rate of binder B into the granulator (introduction rate of binder A / introduction rate of binder B) is greater than 0.1 and less than 1.0.

Description

Technical Field

[0001] The present invention relates to a method for producing a catalyst for producing an unsaturated carboxylic acid. More specifically, it relates to a method for producing a catalyst for producing an unsaturated carboxylic acid, which is used when producing an unsaturated carboxylic acid by catalytic gas-phase oxidation of an unsaturated aldehyde such as acrolein or methacrolein with an oxygen-containing gas.

Background Art

[0002] In general, a catalyst containing molybdenum as an essential component is used as a catalyst for producing an unsaturated carboxylic acid by catalytic gas-phase oxidation of an unsaturated aldehyde such as acrolein or methacrolein with an oxygen-containing gas. Specifically, improvements in the catalyst and its production method used when producing acrylic acid, methacrylic acid, etc. using acrolein, methacrolein, etc. as raw materials are being vigorously promoted from various viewpoints. The production of an unsaturated carboxylic acid is carried out by catalytic gas-phase oxidation of an unsaturated aldehyde such as acrolein or methacrolein with an oxygen-containing gas in a fixed-bed reactor filled with a catalyst.

[0003] The catalyst filled in the fixed-bed reactor has a shape such as a cylinder shape, a ring shape, a tablet shape, a spherical shape, etc. Generally, a catalyst formed by molding a powder of a catalyst active component or a catalyst in which catalyst component elements are supported on an inert carrier having the same shape as the above-mentioned shape is used.

[0004] By the way, since a fixed-bed reactor filled with a catalyst is used, the load on the catalyst during the reaction is high, so the catalyst is likely to be damaged or pulverized. When damage, pulverization, etc. occur, there is a problem that the pressure rises during the reaction. In contrast, a method is known in which a catalyst having high catalyst performance such as raw material conversion rate and product selectivity and high mechanical strength is used to prevent damage and pulverization of the catalyst.

[0005] Known methods for producing such catalysts include adjusting the relative centrifugal acceleration when granulating using a rolling granulator (Patent Document 1), heating and drying the catalyst starting material mixture to form a liquid binder and then calcining it (Patent Document 2), using specific raw materials as catalyst raw materials when preparing the catalyst (Patent Document 3), and adding the binder in two parts when preparing the catalyst (Patent Documents 4-8). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-111720 [Patent Document 2] Japanese Patent Publication No. 2004-160342 [Patent Document 3] Japanese Patent Publication No. 2001-79408 [Patent Document 4] Japanese Patent Publication No. 2021-146252 [Patent Document 5] Japanese Patent Publication No. 2021-146253 [Patent Document 6] Japanese Patent Publication No. 2021-146254 [Patent Document 7] Japanese Patent Publication No. 2021-146255 [Patent Document 8] Japanese Patent Publication No. 2021-146256 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, with conventionally known catalysts for producing unsaturated carboxylic acids, when the catalyst is packed into a reactor and used to carry out a gas-phase catalytic oxidation reaction of unsaturated aldehydes such as acrolein and methacrolein to produce the corresponding unsaturated carboxylic acid, the mechanical strength of the catalyst is not always sufficient, and, There were problems with low yields due to low raw material conversion rates and low selectivity for the corresponding unsaturated carboxylic acids.

[0008] Furthermore, in the method of adding the binder in two parts as described in Patent Documents 4 to 8, the temperature of the heat medium used when carrying out the gas-phase catalytic oxidation reaction with the resulting catalyst is high, at 260°C. From the viewpoint of thermal efficiency, a lower heat medium temperature, i.e., a lower reaction temperature, is preferable. However, lowering the heat medium temperature leads to a decrease in the conversion rate and a decrease in the yield of the corresponding unsaturated carboxylic acid, as shown in Comparative Example 4 below.

[0009] The present invention was made to solve the above-mentioned problems. Specifically, the objective is to provide a catalyst used in the synthesis of unsaturated carboxylic acids such as acrylic acid and methacrylic acid by gas-phase catalytic oxidation of unsaturated aldehydes such as acrolein and methacrolein with an oxygen-containing gas, which can improve mechanical strength even under conditions of high load on the catalyst, exhibit excellent conversion rate of raw materials, have high selectivity for the desired unsaturated carboxylic acid, produce in high yield, and enable stable gas-phase catalytic oxidation reactions over long periods. Furthermore, from the viewpoint of thermal efficiency, the objective is to provide a catalyst that can ensure excellent conversion rate of raw materials, high selectivity for unsaturated carboxylic acids, and sufficient yield even under conditions of low heat medium temperature in the gas-phase catalytic oxidation reaction, i.e., conditions of low reaction temperature. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above problems and have found a method for producing a catalyst for unsaturated carboxylic acid, which includes a molding step in which a carrier is introduced into a granulator, then a first binder, Binder A, is introduced, then a powder containing catalyst component elements and a second binder, Binder B, is introduced, and the powder containing the catalyst component elements is supported on the carrier to form a catalyst precursor, wherein the ratio of the introduction rate of Binder A to the introduction rate of Binder B into the granulator (introduction rate of Binder A / introduction rate of Binder B) is set within a specific range to form a catalyst precursor, and the resulting catalyst for producing unsaturated carboxylic acid, when filled into a reactor, We have discovered that the catalytic strength can be improved, and that when unsaturated aldehydes such as acrolein and methacrolein are oxidized in gas phase with an oxygen-containing gas using this catalyst for producing unsaturated carboxylic acids, the conversion rate of unsaturated aldehydes such as acrolein and methacrolein is excellent even under conditions of high load on the catalyst, and the selectivity of unsaturated carboxylic acids such as acrylic acid and methacrylic acid is good. As a result, it is possible to improve the yield of unsaturated carboxylic acids such as acrylic acid and methacrylic acid. Furthermore, we have found that even under conditions of low reaction temperature, it is possible to achieve excellent conversion rates of the raw materials, high selectivity of unsaturated carboxylic acids, and sufficient yield, leading to the present invention.

[0011] In other words, the gist of this invention is as follows: [1] A method for producing a catalyst for producing an unsaturated carboxylic acid, comprising a molding step of introducing a carrier into a granulator, then introducing a binder A which is a first binder, further introducing a powder containing catalyst component elements and a second binder B which is a second binder, and supporting the powder containing the catalyst component elements on the carrier to form a catalyst precursor, wherein the catalyst component elements include molybdenum (Mo), vanadium (V), and copper (Cu), and the ratio of the introduction rate of binder A into the granulator to the introduction rate of binder B (introduction rate of binder A / introduction rate of binder B) is greater than 0.1 and less than 1.0.

[0012] [2] A method for producing a catalyst for producing an unsaturated carboxylic acid, comprising a molding step in which a carrier is introduced into a granulator, then a binder A which is the next binder, then a powder containing a catalyst component element and a second binder B which is introduced, and the powder containing the catalyst component element is supported on the carrier to form a catalyst precursor, wherein the catalyst component element is molybdenum (Mo) A method for producing a catalyst for unsaturated carboxylic acid, comprising vanadium (V) and copper (Cu), wherein the ratio of the introduction rate of binder A into the granulator to the introduction rate from the start of introduction of binder B to the end of introduction of 90% by mass of the total amount of binder B (introduction rate of binder A / introduction rate from the start of introduction of binder B to the end of introduction of 90% by mass) is greater than 0.1 and less than 1.0.

[0013] [3] A method for producing a catalyst for producing an unsaturated carboxylic acid, comprising a molding step of introducing a carrier into a granulator, then introducing a first binder, Binder A, then introducing a powder containing catalyst component elements and a second binder, Binder B, and supporting the powder containing the catalyst component elements on the carrier to form a catalyst precursor, wherein the catalyst component elements include molybdenum (Mo), vanadium (V), and copper (Cu), and the ratio of the introduction rate of Binder A into the granulator to the introduction rate from the start of introduction of Binder B to the end of introduction of 80% by mass of the total amount of Binder B (introduction rate of Binder A / introduction rate from the start of introduction of Binder B to the end of introduction of 80% by mass) is greater than 0.1 and less than 1.0.

[0014] [4] A method for producing a catalyst for producing an unsaturated carboxylic acid according to any one of the claims [1] to [3], wherein the total amount of the binder introduced into the granulator is 5% by mass or more and 30% by mass or less relative to the amount of the carrier introduced into the granulator. [5] A method for producing an unsaturated carboxylic acid catalyst according to any one of the claims [1] to [3], wherein the total amount of binder introduced into the granulator is 10% by mass or more and 40% by mass or less relative to the amount of powder containing the catalyst component elements introduced into the granulator.

[0015] [6] The method for producing a catalyst for producing an unsaturated carboxylic acid according to any one of [1] to [3], wherein the binder A and the binder B contain an organic compound. [7] The method for producing a catalyst for producing an unsaturated carboxylic acid according to any one of [1] to [3], wherein the amount of the binder A introduced into the granulator is 2% by mass or more and 90% by mass or less based on the total amount of the binder introduced into the granulator, and the amount of the binder B introduced into the granulator is 10% by mass or more and 98% by mass or less based on the total amount of the binder introduced into the granulator.

[0016] [8] The method for producing a catalyst for producing an unsaturated carboxylic acid according to any one of [1] to [3], wherein the catalyst component elements of the catalyst for producing an unsaturated carboxylic acid are represented by the following formula (1). Mo 12 V a X b Cu c Y d Sb e Z f Si g C h O i (1) (In the formula (1), X represents Nb and / or W, Y represents at least one element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, and Z represents at least one element selected from the group consisting of Fe, Co, Ni, and Bi. a to i represent the atomic ratios of the respective elements, and are in the ranges of 0 < a ≤ 12, 0 ≤ b ≤ 12, 0 < c ≤ 12, 0 ≤ d ≤ 8, 0 ≤ e ≤ 500, 0 ≤ f ≤ 500, 0 ≤ g ≤ 500, 0 ≤ h ≤ 500, and i is a value that satisfies the oxidation state of the other elements.) [9] A method for producing acrylic acid by gas-phase catalytic oxidation of acrolein with an oxygen-containing gas using a catalyst for producing an unsaturated carboxylic acid produced by the production method according to any one of [1] to [3]. [Advantages of the Invention]

[0017] The catalyst for producing unsaturated carboxylic acids produced by the manufacturing method of the present invention can improve mechanical strength, and when unsaturated aldehydes such as acrolein and methacrolein are oxidized in gas phase with an oxygen-containing gas using this catalyst, the conversion rate of unsaturated aldehydes such as acrolein and methacrolein is excellent, even under conditions of high load on the catalyst, and the selectivity for unsaturated carboxylic acids such as acrylic acid and methacrylic acid is good, resulting in an improved yield of unsaturated carboxylic acids such as acrylic acid and methacrylic acid. This enables stable gas-phase catalytic oxidation reactions over long periods. In particular, when acrolein is oxidized in the gas phase with an oxygen-containing gas, even under conditions of high catalyst load, the conversion rate of acrolein is excellent and the selectivity of acrylic acid is good, resulting in an improved yield of acrylic acid and enabling stable gas-phase catalytic oxidation reactions over long periods. Furthermore, even under low reaction temperature conditions, the conversion rate of the raw materials is excellent, the selectivity for unsaturated carboxylic acids is high, and sufficient yield can be ensured, thereby reducing running costs in commercial plants and maintaining the stability of the reaction process. [Modes for carrying out the invention]

[0018] The embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following description and can be implemented in various modifications within the scope of its gist.

[0019] The method for producing the catalyst for unsaturated carboxylic acid according to this invention (hereinafter sometimes simply referred to as "catalyst") will be described in detail below. The catalyst according to this invention is a catalyst for the synthesis of unsaturated carboxylic acids, which uses unsaturated aldehydes such as acrolein and methacrolein (hereinafter sometimes simply referred to as "unsaturated aldehydes") as raw materials to produce unsaturated carboxylic acids such as acrylic acid and methacrylic acid (hereinafter sometimes simply referred to as "unsaturated carboxylic acids"). In particular, the catalyst uses acrolein as a raw material and produces acrylic acid particularly efficiently by gas-phase catalytic oxidation with an oxygen-containing gas.

[0020] <Method for manufacturing a catalyst> The catalyst according to the present invention can be manufactured by a method that includes a molding step for manufacturing a catalyst precursor and a calcination step for calcining the catalyst precursor obtained in the molding step.

[0021] <Molding process> The molding process involves introducing a carrier into a granulator, then introducing a portion of the binder, and finally introducing a powder containing catalyst elemental components and the remaining binder to obtain a catalyst precursor. Specifically, first, the carrier is introduced into the granulator. Next, the binder is divided into a first binder (sometimes referred to as "binder A") and a second binder (sometimes referred to as "binder B"), and binder A is introduced into the granulator. Next, powders containing the elements that constitute the catalyst (hereinafter sometimes referred to as "catalyst component elements") and the binder B are introduced as the respective components of the catalyst. This allows the powder containing the catalyst component elements to be supported on the carrier to obtain a catalyst precursor, which can then be used to manufacture a catalyst.

[0022] As for the molding process, for example, a method can be used in which a granulator used in the rolling granulation method (rolling granulator) is used to support a powder containing catalyst elemental components on the surface of a carrier. Specifically, as the granulator, for example, a granulator having a flat or uneven disc at the bottom of the granulator is used, and by rotating the disc of the granulator, the carrier introduced into the granulator is stirred by repeated rotation and revolution motion, then binder A is introduced, followed by the introduction of powder containing catalyst elemental components and binder B, and other additives may be added, thereby supporting the powder on the carrier. Since the powder can be uniformly supported on the carrier, it is preferable to use a rolling granulator as the granulator.

[0023] [carrier] Examples of the aforementioned carriers include spherical carriers such as silica, silicon carbide, alumina, mullite, and alundum. The size of the carrier is preferably such that the long axis diameter is 2.5 mm to 10 mm, and more preferably 2.5 mm to 6 mm. Furthermore, the porosity of the carrier is preferably 20% to 60%, more preferably 30% to 57%, and even more preferably 40% to 55%. The water absorption rate of the carrier is preferably 10% to 60%, more preferably 12% to 50%, and even more preferably 15% to 40%. By setting the porosity and water absorption rate of the carrier within the above ranges, the powder containing the catalyst component elements can be easily supported on the carrier. Furthermore, it is preferable that the support is inert to the reaction in which unsaturated aldehydes are catalytically oxidized in the gas phase with an oxygen-containing gas.

[0024] [Powder containing catalytic elemental components] The powder containing the aforementioned catalyst element can be obtained by the following process. First, a compound having a catalytic component element is used as a catalyst source compound (hereinafter referred to as "source compound"), and each of these source compounds having a catalytic component element is added to a solvent or solution to integrate them, and if necessary, heated to obtain a prepared solution (preparation step), and the prepared solution is dried to obtain a powder (drying step), thereby obtaining a powder containing the aforementioned catalytic component element.

[0025] (liquid preparation process) The aforementioned liquid preparation step involves integrating each source compound containing the catalyst component element in an aqueous system and heating it to obtain a prepared liquid. The aforementioned integration in an aqueous system refers to the process of integrating each source compound by adding it to an aqueous solvent or solution. This aqueous solvent is an aqueous medium for dissolving or suspending each source compound, and refers to a solvent consisting of water, an organic solvent that is miscible with water such as methanol or ethanol, or a mixture thereof. Furthermore, the aforementioned aqueous solution refers to a liquid obtained by dissolving, suspending, or integrating one or more source compounds in the aforementioned aqueous solvent.

[0026] The aforementioned integration refers to mixing aqueous solutions or aqueous dispersions of the source compounds for each catalyst element all at once or in stages, and heating as necessary. Specifically, this includes methods such as mixing each source compound all at once, mixing each source compound all at once and then heating, mixing each source compound in stages, repeatedly mixing and heating each source compound in stages, and methods combining these methods. All of these are included in the concept of integration of the source compounds for each catalyst element.

[0027] The aforementioned heating refers to stirring the mixture or mixed dispersion obtained in the integration process at a predetermined temperature for a predetermined time. This heating increases the viscosity of the mixture or mixed dispersion, which in the case of a mixed dispersion reduces the sedimentation of solid components and is particularly effective in suppressing non-uniformity of components in the subsequent drying process, resulting in better catalytic activity of the final product, the catalyst, such as the raw material conversion rate and product selectivity.

[0028] The heating temperature is preferably 60°C to 100°C, more preferably 60°C to 90°C, and even more preferably 70°C to 90°C. A heating temperature within this range may result in good activity of the manufactured catalyst.

[0029] The heating time is preferably 2 to 12 hours, and more preferably 3 to 8 hours. A heating time within this range may result in good activity of the manufactured catalyst. Any method can be used for the stirring method, such as a method using a stirrer with stirring blades or a method using external circulation with a pump.

[0030] (source compound) This catalyst preferably contains molybdenum (Mo), vanadium (V), and copper (Cu) as catalytic elemental components, and may also contain one or more of the following other catalytic elemental components: niobium (Nb), tungsten (W), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), zinc (Zn), antimony (Sb), iron (Fe), cobalt (Co), nickel (Ni), bismuth (Bi), silicon (Si), and carbon (C).

[0031] Examples of molybdenum (Mo) source compounds include ammonium paramolybdate, molybdenum trioxide, molybdic acid, ammonium phosphomolybdate, and phosphomolybdic acid.

[0032] Examples of vanadium(V) source compounds include ammonium vanadate, ammonium metavanadate, vanadium pentoxide, vanadium oxalate, and vanadium sulfate. The amount of vanadium added is preferably such that, as an atomic ratio of catalyst elemental components, the ratio is greater than 0 and less than or equal to 12, with molybdenum atoms being 12; more preferably between 0.1 and 6; even more preferably between 0.5 and 5; and particularly preferably between 1 and 3. Within this range, a catalyst with excellent raw material conversion rate can be obtained, enabling the production of unsaturated carboxylic acids with high selectivity.

[0033] Examples of copper (Cu) source compounds include copper sulfate, copper nitrate, and cuprous chloride. The amount of copper added is preferably such that, when the atomic ratio of the catalyst component elements is set to 12, the amount is greater than 0 and less than or equal to 12, more preferably between 0.1 and 6, and even more preferably between 0.5 and 4. Within this range, a catalyst can be obtained that exhibits excellent raw material conversion rates and can produce unsaturated carboxylic acids with high selectivity.

[0034] Examples of the source compound for niobium (Nb) include niobium hydroxide. Examples of the source compound for tungsten (W) include tungstic acid or its salts. The amount of niobium and / or tungsten added is preferably between 0 and 12, more preferably between 0.1 and 6, and even more preferably between 0.5 and 4, when the amount of molybdenum atoms is set to 12. Within this range, a catalyst can be obtained that exhibits excellent raw material conversion rates and can produce unsaturated carboxylic acids with high selectivity.

[0035] Examples of magnesium (Mg) source compounds include magnesium oxide, magnesium carbonate, or magnesium sulfate. Examples of calcium (Ca) source compounds include calcium oxide, calcium carbonate, or calcium hydroxide. Examples of strontium (Sr) source compounds include strontium oxide, strontium carbonate, strontium hydroxide, or strontium nitrate. Examples of barium (Ba) source compounds include barium oxide, barium carbonate, barium nitrate, barium acetate, or barium sulfate. Examples of zinc (Zn) source compounds include zinc oxide, zinc carbonate, zinc hydroxide, or zinc nitrate. The amount of at least one element selected from the group consisting of magnesium, calcium, strontium, barium, and zinc added is preferably such that, when the atomic ratio of the catalyst component elements is set to 12, the ratio is between 0 and 8, more preferably between 0 and 6, and even more preferably between 0 and 4. Within this range, a catalyst can be obtained that exhibits excellent raw material conversion rates and can produce unsaturated carboxylic acids with high selectivity.

[0036] Examples of antimony (Sb) source compounds include antimony oxides such as antimony trioxide and antimony pentoxide, trivalent antimony compounds such as antimony acetate, and pentavalent antimony compounds. The amount of antimony added is preferably such that, as an atomic ratio of catalyst component elements, the number of molybdenum atoms is 0 to 500, more preferably 0.1 to 100, and even more preferably 0.2 to 50. Within this range, a catalyst can be obtained that exhibits excellent raw material conversion rates and can produce unsaturated carboxylic acids with high selectivity.

[0037] Examples of iron (Fe) source compounds include ferric nitrate, ferric sulfate, ferric chloride, and ferric acetate. Examples of cobalt (Co) source compounds include cobalt nitrate, cobalt sulfate, cobalt chloride, cobalt carbonate, and cobalt acetate. Examples of nickel (Ni) source compounds include nickel nitrate, nickel sulfate, nickel chloride, nickel carbonate, and nickel acetate. Examples of bismuth (Bi) source compounds include bismuth chloride, bismuth nitrate, bismuth oxide, and bismuth subcarbonate. The amounts of iron, cobalt, nickel, and bismuth added are preferably such that, when the atomic ratio of the catalyst components is set to 12, the total number of atoms is between 0 and 500, more preferably between 0 and 100, and even more preferably between 0 and 50. Within this range, the catalyst can be made that exhibits excellent raw material conversion rates and can produce unsaturated carboxylic acids with high selectivity.

[0038] Examples of silicon (Si) source compounds include silica, granular silica, colloidal silica, and fumed silica. Examples of carbon (C) source compounds include green silicon carbide and black silicon carbide, in which carbon and silicon are integrated, and fine powder silicon carbide is preferred. The amount of carbon added is preferably such that, when the atomic ratio of the catalyst component elements is set to 12, the amount of carbon is between 0 and 500, more preferably between 0 and 400, and even more preferably between 0 and 300. Within this range, the catalyst can be made that exhibits excellent raw material conversion rates and can produce unsaturated carboxylic acids with high selectivity. Furthermore, the amount of silicon added, including the amount of silicon contained in the carbon source compound, is preferably added so that the atomic ratio of the catalyst component elements is between 0 and 500, more preferably between 0 and 400, and even more preferably between 0 and 300, with molybdenum atoms set to 12. Within this range, a catalyst can be obtained that exhibits excellent raw material conversion rates and can produce unsaturated carboxylic acids with high selectivity.

[0039] (Method for adding source compounds) In the aforementioned liquid preparation step, all of the source compounds may be used to make one prepared liquid, or each source compound may be used individually or divided into several groups to make multiple prepared liquids, and these multiple prepared liquids may be mixed at once or sequentially to make one prepared liquid, or one or more prepared liquids may be dried or calcined to make a solid, and this solid may be added to the prepared liquid made from the remaining source compounds to make a new prepared liquid.

[0040] (drying process) The prepared solution is dried in a drying process to obtain a powder containing catalyst elemental components (hereinafter sometimes simply referred to as "powder"). There are no particular limitations on the drying method in this drying process; for example, a conventional spray dryer, slurry dryer, drum dryer, etc., may be used to obtain the powder.

[0041] (Heat treatment) The powder obtained by the drying process may be further subjected to heat treatment if necessary. The heat treatment is a treatment carried out in air at a temperature range of 200°C to 400°C, preferably 250°C to 350°C, for a short time. There is no particular limitation on the method. For example, the powder may be heated in a fixed state using an ordinary box-type heating furnace, a tunnel-type heating furnace, etc., or the powder may be heated while being fluidized using a rotary kiln or the like. In addition, the dried product obtained by the drying process or the heat treatment, which has further undergone processes such as pulverization, is also the powder in the present invention.

[0042] (Components of the powder) In addition, the catalyst component elements of the powder obtained by the drying process preferably contain molybdenum and vanadium, more preferably contain copper in addition, and among them, it is even more preferable that they are represented by the following general formula (1). By setting the catalyst component elements of the powder within the above range, the manufactured catalyst can improve mechanical strength, and even under high-load conditions, it has excellent raw material conversion rate, good selectivity for unsaturated carboxylic acids, and can improve the yield of unsaturated carboxylic acids.

[0043] Mo 12 V a X b Cu c Y d Sb e Z f Si g C h O i (1) (In formula (1), X represents Nb and / or W, Y represents at least one element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, Z represents at least one element selected from the group consisting of Fe, Co, Ni, and Bi. a to i represent the atomic ratios of the respective elements, and are in the ranges of 0 < a ≤ 12, 0 ≤ b ≤ 12, 0 < c ≤ 12, 0 ≤ d ≤ 8, 0 ≤ e ≤ 500, 0 ≤ f ≤ 500, 0 ≤ g ≤ 500, 0 ≤ h ≤ 500, and i is a value that satisfies the oxidation state of other elements.)

[0044] (Amount of powder relative to amount of carrier) The amount of powder containing the catalyst component elements relative to the amount of carrier introduced into the granulator is preferably 20% by mass or more and 100% by mass or less. The lower limit is more preferably 30% by mass and even more preferably 40% by mass. The upper limit is more preferably 90% by mass and even more preferably 80% by mass. By keeping the amount within this range, the manufactured catalyst can have improved mechanical strength, exhibit excellent raw material conversion rate even under high load conditions, have good selectivity for unsaturated carboxylic acids, and improve the yield of unsaturated carboxylic acids.

[0045] [binder] The binder is used to hold the powder on the carrier, and as described above, it is used in two parts: a first binder (binder A) and a second binder (binder B). Binder A is a binder that is introduced into the granulator after the carrier has been introduced and before the powder containing the catalyst element is introduced into the granulator. The binder A may be introduced into the granulator in a desired amount continuously, or it may be divided into multiple portions and introduced with time intervals between portions, but from the viewpoint of uniformity, it is preferable to introduce it continuously.

[0046] Furthermore, the binder B is a binder that is introduced into the granulator at the same time as the powder containing the catalyst element, or after the powder containing the catalyst element has been introduced. The following methods can be used to introduce the powder containing the catalyst element and the binder B into the granulator. (1) A method of preparing a homogeneous mixture by mixing a powder containing catalyst element elements with binder B, and introducing the homogeneous mixture into a granulator. (2) A method of introducing the powder containing the catalyst element and binder B into the granulator simultaneously in separate states. (3) After introducing the powder containing the catalyst element into the granulator, introduce Binder B into the granulator. How to (4) A method of adding binder B to a powder containing catalyst element elements to form a heterogeneous mixture, and introducing the heterogeneous mixture into a granulator. (5) A method of introducing the powder containing the catalyst element and binder B into a granulator in separate states, divided into portions, simultaneously, alternately, or in any order. These are some examples.

[0047] In the present invention, methods such as adding the entire amount by appropriately combining (1) to (5) can be arbitrarily adopted. Of these, in (5), it is preferable to adjust the addition rate using an auto feeder or the like so that a predetermined amount is supported on the carrier without, for example, the powder containing the catalyst component element adhering to the inner wall of the granulator or the like, or the powder containing the catalyst component element agglomerating with each other.

[0048] In the method for producing the catalyst of the present invention, the methods described above (1) to (5) can be combined as appropriate. However, from the viewpoint of uniformly supporting the powder containing the catalyst component elements and binder B on the carrier, it is preferable to adopt methods (2) or (5). Method (5) is preferred because the produced catalyst can have improved mechanical strength, exhibits excellent raw material conversion rate even under high load conditions, has good selectivity for unsaturated carboxylic acids, and is likely to improve the yield of unsaturated carboxylic acids. Furthermore, in method (5), if a binder is introduced into the granulator before the powder containing the catalyst element, that binder corresponds to binder A.

[0049] Examples of the aforementioned binders include inorganic compounds such as water, sulfuric acid, ammonium sulfate, nitric acid, ammonium nitrate, and ammonium carbonate, and organic compounds such as ethylene glycol, glycerin, propionic acid, maleic acid, benzyl alcohol, propyl alcohol, butyl alcohol, polyvinyl alcohol, stearic acid, or phenol.

[0050] The binder preferably contains an organic compound, more preferably an organic compound having a hydroxyl group, and even more preferably glycerin and / or polyvinyl alcohol. By including the above compounds as the binder (binder A or binder B), the manufactured catalyst can have improved mechanical strength, exhibit excellent raw material conversion rate even under high load conditions, have good selectivity for unsaturated carboxylic acids, and improve the yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured. When the binder is introduced into the granulator, it is preferably in the form of an aqueous solution, and the concentration of the aqueous solution is preferably 2% by mass or more and 50% by mass or less. The lower limit is more preferably 3% by mass, and the upper limit is more preferably 40% by mass. This range makes it possible to uniformly disperse the binder into the carrier or powder within the granulator.

[0051] The types of binders used in Binder A and Binder B may be the same or different, but it is preferable that they be the same from the viewpoint of uniformity. Furthermore, both Binder A and Binder B may use one type of binder or multiple types, and if multiple types are used, they may be introduced into the granulator separately or mixed and introduced into the granulator.

[0052] The amount of binder A introduced into the granulator is preferably 2% by mass or more and 90% by mass or less of the total amount of binder introduced into the granulator, and the amount of binder B introduced into the granulator is preferably 10% by mass or more and 98% by mass or less of the total amount of binder introduced into the granulator. The upper limit of the amount of binder A is preferably 85% by mass, more preferably 80% by mass, and 75% by mass. A certain percentage is more preferable, and 70% by mass is particularly preferable. The lower limit of the amount of binder A is preferably 3% by mass, more preferably 4% by mass, and even more preferably 5% by mass.

[0053] Accordingly, the upper limit of the amount of binder B is preferably 97% by mass, more preferably 96% by mass, and even more preferably 95% by mass. The lower limit of the amount of binder B is preferably 15% by mass, more preferably 20% by mass, even more preferably 25% by mass, and particularly preferably 30% by mass. Since it falls within the aforementioned range, the manufactured catalyst can improve mechanical strength, exhibit excellent raw material conversion rate even under high load conditions, and have good selectivity for unsaturated carboxylic acids, making it possible to improve the yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured.

[0054] Furthermore, the introduction speed of binders A and B into the granulator can be adjusted to achieve the effects of the present invention. The relationship between the introduction speed of binder A and the introduction speed of binder B is preferably as follows:

[0055] Regarding the introduction of binder A into the granulator, the value obtained by dividing the total amount of binder A introduced by the time from the start of introduction of binder A to the start of introduction of the powder containing the catalyst element is referred to as the "introduction rate of binder A," and its abbreviation is referred to as "VA." Furthermore, regarding the introduction of binder B into the granulator, the value obtained by dividing the total amount of binder B introduced by the time from the start of introduction of binder B to the end of introduction of a predetermined amount of binder B is referred to as the "introduction rate of binder B." Furthermore, the abbreviation for the introduction speed from the start of introducing the binder B into the granulator until 80% by mass of the total amount of binder B has been introduced is referred to as "VB80", the abbreviation for the introduction speed from the start of introducing the binder B into the granulator until 90% by mass of the total amount of binder B has been introduced is referred to as "VB90", and the abbreviation for the introduction speed from the start of introducing the binder B into the granulator until the entire amount of binder B has been introduced is referred to as "VB100".

[0056] The ratio of VA to VB80 (VA / VB80) is greater than 0.1 and less than 1.0, preferably greater than 0.1 and 0.9 or less, more preferably 0.3 or more and 0.9 or less, and even more preferably 0.5 or more and 0.9 or less. Because it is within the above range, the manufactured catalyst can improve mechanical strength, has excellent raw material conversion rate even under high load conditions, has good selectivity for unsaturated carboxylic acids, and can improve the yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured.

[0057] Furthermore, the ratio of VA to VB90 (VA / VB90) is greater than 0.1 and less than 1.0, preferably greater than 0.1 and 0.9 or less, more preferably 0.3 or more and 0.9 or less, and even more preferably 0.5 or more and 0.9 or less. Because it is within the above range, the manufactured catalyst can improve mechanical strength, has excellent raw material conversion rate even under high load conditions, has good selectivity for unsaturated carboxylic acids, and can improve the yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured.

[0058] Furthermore, the ratio of VA to VB100 (VA / VB100) is greater than 0.1 and less than 1.0, preferably greater than 0.1 and 0.9 or less, more preferably 0.3 or more and 0.9 or less, and even more preferably 0.5 or more and 0.9 or less. As a result, the manufactured catalyst can have improved mechanical strength, exhibit excellent raw material conversion rates even under high load conditions, and have good selectivity for unsaturated carboxylic acids, making it possible to improve the yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured.

[0059] The introduction rate of binder A is calculated by dividing the total amount of binder A introduced into the granulator by the time elapsed from the start of binder A introduction to the start of the introduction of the powder containing the catalyst element. In other words, even if there is a period of time when binder A is not introduced between the start of binder A introduction and the start of the introduction of the powder containing the catalyst element, that time is not subtracted. Similarly, the introduction rate of binder B is calculated by dividing the total amount of binder B introduced into the granulator by the time elapsed from the start of binder B introduction to the end of the introduction of a predetermined amount. In other words, even if there is a period of time when binder B is not introduced between the start of binder B introduction and the end of binder B introduction, that time is not subtracted.

[0060] The total amount of the binder relative to the amount of the carrier introduced into the granulator is preferably 5% by mass or more and 30% by mass or less. The lower limit is more preferably 10% by mass, and even more preferably 13% by mass. The upper limit is more preferably 25% by mass, and even more preferably 22% by mass. By keeping it within the above range, the manufactured catalyst can have improved mechanical strength, excellent raw material conversion rate even under high load conditions, good selectivity for unsaturated carboxylic acids, and an improved yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured.

[0061] The introduction rate of the binder A into the granulator with respect to the amount of carrier is preferably 0.15 g / min to 8.8 g / min when the amount of carrier is 0.1 kg to 1 kg. The lower limit is more preferably 0.25 g / min, and even more preferably 0.30 g / min. The upper limit is more preferably 8.5 g / min, and even more preferably 8.3 g / min. Furthermore, when the amount of carrier is 1 kg to 10 kg, it is preferable to introduce the binder A with respect to the amount of carrier to 7.0 g / min or more. Furthermore, when the amount of carrier is 10 kg to 1000 kg, it is preferable to introduce the binder A with respect to the amount of carrier to 7.0 g / min or more. The upper limit is more preferably 2720g / min, and even more preferably 2700g / min. By keeping the catalyst within the aforementioned range, the manufactured catalyst can have improved mechanical strength, exhibit excellent raw material conversion rates even under high load conditions, and have good selectivity for unsaturated carboxylic acids, thereby improving the yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured.

[0062] Furthermore, the introduction rate of the binder A into the granulator for the powder is preferably 0.15 g / min to 8.8 g / min when the amount of powder is 0.05 kg to 1 kg. The lower limit is more preferably 0.25 g / min, and even more preferably 0.30 g / min. The upper limit is more preferably 8.5 g / min, and even more preferably 8.3 g / min. Furthermore, when the amount of powder is 1 kg to 10 kg, it is preferably 1.0 g / min to 59.5 g / min. The lower limit is more preferably 1.1 g / min, and even more preferably 1.2 g / min. The upper limit is more preferably 59.0 g / min, and even more preferably 58.5 g / min. Furthermore, when the amount of powder is 10 kg to 1000 kg, it is preferably 7.0 g / min to 2740 g / min. The lower limit is more preferably 9.0 g / min, and even more preferably 11.0 g / min. The upper limit is more preferably 2720g / min, and even more preferably 2700g / min. By keeping the catalyst within the aforementioned range, the manufactured catalyst can have improved mechanical strength, exhibit excellent raw material conversion rates even under high load conditions, and have good selectivity for unsaturated carboxylic acids, thereby improving the yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured.

[0063] The total amount of the binder relative to the amount of the powder containing the catalyst element introduced into the granulator is preferably 10% by mass or more and 40% by mass or less. The lower limit is more preferably 13% by mass, and even more preferably 15% by mass. The upper limit is more preferably 35% by mass, and even more preferably 33% by mass. By keeping it within the above range, the manufactured catalyst can have improved mechanical strength, and even under high load conditions, it can have excellent raw material conversion rate and good selectivity for unsaturated carboxylic acids, thereby improving the yield of unsaturated carboxylic acids. Furthermore, even under conditions where the heat transfer medium temperature during the reaction is low, i.e., under conditions where the reaction temperature is low, the raw material conversion rate is excellent, the selectivity for unsaturated carboxylic acids is high, and a sufficient yield can be ensured.

[0064] [Forming aid] In the molding process, other molding aids may be added in addition to the carrier, powder, and binder described above. Examples of other molding aids include silica, alumina, glass, silicon carbide, silicon nitride, graphite, cellulose, methylcellulose, and starch.

[0065] <Firing Process> The catalyst precursor obtained in the molding process can be converted into a catalyst by calcining the catalyst precursor (calcination process). The calcination process is carried out by calcining the catalyst precursor in a suitable oxygen atmosphere at a temperature of preferably 300°C to 500°C, more preferably 350°C to 450°C, for about 1 to 16 hours. The calcination method can be the same as the heat treatment method used in the drying process. As described above, the mechanical strength can be improved, and a catalyst with high activity and excellent unsaturated carboxylic acid yield can be obtained.

[0066] <Catalyst> The obtained catalyst preferably contains molybdenum and vanadium as catalyst component elements, more preferably contains copper in addition, and most preferably is represented by the following general formula (1). By setting the catalyst component elements of the catalyst within the above range, the produced catalyst can improve the mechanical strength, and even under high load conditions, it has excellent raw material conversion rate, good selectivity of unsaturated carboxylic acid, and can improve the yield of unsaturated carboxylic acid.

[0067] Mo 12 V a X b Cu c Y d Sb e Z f Si g C h O i (1) (In formula (1), X represents Nb and / or W, Y represents at least one element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, and Z represents at least one element selected from the group consisting of Fe, Co, Ni, and Bi. a to i represent the atomic ratios of the respective elements, and are in the ranges of 0 < a ≤ 12, 0 ≤ b ≤ 12, 0 < c ≤ 12, 0 ≤ d ≤ 8, 0 ≤ e ≤ 500, 0 ≤ f ≤ 500, 0 ≤ g ≤ 500, 0 ≤ h ≤ 500, and i is a value that satisfies the oxidation state of other elements.) Note that the catalyst component elements of the catalyst refer to those obtained by removing the carrier from the catalyst.

[0068] [Gas-phase catalytic oxidation reaction] The gas-phase catalytic oxidation reaction carried out using this catalyst can be performed by the following method. [[ID=4,2]] First, a predetermined amount of the catalyst is packed into a reaction tube of a predetermined size. Next, the reaction tube is heated with a heat transfer medium to adjust the temperature inside the tube to a predetermined reaction temperature. Then, a raw material mixture gas containing unsaturated aldehydes such as acrolein and methacrolein, and oxygen gas, is introduced into the inlet of the reaction tube and passed through the catalyst at a predetermined space velocity to carry out the reaction, and the reaction gas is recovered from the outlet of the reaction tube. The size of the reaction tube at this time can be any size, and the space velocity and heat transfer medium temperature are adjusted to obtain an appropriate rate and temperature for obtaining an appropriate raw material conversion rate, an appropriate selectivity for the unsaturated carboxylic acid, and an appropriate yield.

[0069] By setting the ratio of the introduction rate of binder A to the introduction rate of binder B into the granulator (introduction rate of binder A / introduction rate of binder B) within the aforementioned range, it becomes possible to achieve excellent raw material conversion rate and good selectivity for unsaturated carboxylic acids, and to improve the yield of unsaturated carboxylic acids, even under conditions of low heat transfer medium temperature.

[0070] [Powdering rate] The catalyst must have sufficient strength. If the catalyst strength is low, when it is packed into a reaction tube or similar device used to produce unsaturated carboxylic acids by gas-phase catalytic oxidation of unsaturated aldehydes with an oxygen-containing gas, the catalyst may pulverize or crack, potentially leading to a large differential pressure (the pressure difference between the inlet and outlet of the reaction tube). A large differential pressure can place a significant load on the compressor and other equipment that blows the raw material mixture gas containing unsaturated aldehydes and oxygen-containing gas into the reaction tube filled with the catalyst. Furthermore, if the catalyst strength is low, the pulverization of the catalyst may accelerate in proportion to the progress of gas-phase catalytic oxidation, and the differential pressure may increase further over time. Therefore, the catalyst pulverization rate, which serves as an indicator of catalyst strength, is preferably 5.0% or less, more preferably 3.0% or less, and even more preferably 2.0% or less. The pulverization rate refers to the ratio of the weight of fine particles to the weight of the catalyst sample when the catalyst is dropped from a height of 1 m, and the measurement method will be described later.

[0071] [Application] By using the catalyst produced by the manufacturing method of the present invention, mechanical strength can be improved, catalytic performance such as raw material conversion rate and product selectivity can be further enhanced, and unsaturated aldehydes such as acrolein and methacrolein can be catalytically oxidized in the gas phase with an oxygen-containing gas to produce corresponding unsaturated carboxylic acids such as acrylic acid and methacrolein in high yield. Among these, acrylic acid can be produced in particularly high yield by catalytically oxidizing acrolein in the gas phase with an oxygen-containing gas. [Examples]

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples as long as it does not exceed the gist of the invention. The acrolein conversion rate, acrylic acid selectivity, and acrylic acid yield are defined as shown in the following equations (1) to (3). (1) Acrolein conversion rate (mol%) = 100 × (moles of acrolein that reacted) / (moles of acrolein supplied) (2) Acrylic acid selectivity (mol%) = 100 × (moles of acrylic acid produced) / (moles of acrolein converted) (3) Acrylic acid yield (mol %) = 100 × (moles of acrylic acid produced) / (moles of acrolein supplied)

[0073] <Gas-phase catalytic oxidation reaction of acrolein> A reaction tube with an inner diameter of 21.4 mm was packed with 33.4 ml of catalyst. Oxygen and nitrogen were added to the gas obtained by gas-phase catalytic oxidation of propylene, and the resulting mixed gas of the following composition was introduced into the inlet of the reaction tube. The reaction was evaluated at a space velocity of 910 / hr. The reaction was performed at heat transfer temperatures of 240°C and 260°C, respectively. The reaction evaluation results are shown in Table 1. The composition of the raw material mixture gas used is as follows: • Acrolein: 7% by volume, Steam: 17% by volume, Oxygen: 6% by volume, (Nitrogen-containing inert gas + other gases): 70% by volume

[0074] <Measurement of catalyst pulverization rate> The catalyst was sieved using a sieve with a mesh size of 2.36 mm, and the sieved material was used as the sample for measuring the pulverization rate. A funnel (with a conical upper opening diameter of 150 mm and a conical lower opening diameter of 25 mm) was inserted into the top of an acrylic cylinder (φ66 mm) that was 1 m high, and a receiving tray was placed at the bottom of the cylinder. Approximately 20 g of the pulverization rate measurement sample was accurately weighed and poured into the conical upper part of the funnel, allowing it to fall through the cylinder into the receiving tray. The pulverized sample that fell was collected from the receiving tray, and the weight of the fine particles sieved using the 2.36 mm mesh sieve (pulverized weight) was measured, and the catalyst pulverization rate was calculated using the following formula. Furthermore, if the pulverization rate measured under the above conditions is 1% or less, it can be concluded that the mechanical strength has improved. Powdering rate (%) = (Weight of powdered material / Weight of sample used for powdering) × 100

[0075] (Example 1) 1800 ml of warm water was placed in a container, and 28 g of ammonium paratungstate was added and dissolved. Next, 60 g of ammonium metavanadate was added and dissolved. Then, 454 g of ammonium molybdate was added and dissolved to obtain a solution (hereinafter referred to as "Solution A"). Next, a solution prepared by dissolving 80g of copper sulfate in 100ml of warm water was added to solution A and mixed until uniform. Then, 34g of niobium hydroxide and 13g of antimony trioxide were added to this mixture and stirred to obtain a starting material mixture. This starting material mixture was spray-dried at 150°C, and then heat-treated in air at a heating temperature of 300°C for 1 hour to obtain a dried product.

[0076] This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as the support powder. 1.0 g of flake glass was added to 69.0 g of this support powder and mixed until uniform to obtain a support mixed powder. 100 g of spherical inert carriers with a diameter of 4.5 mm, mainly composed of alumina-silica, were introduced into a rolling granulator, and then 3.0 g of binder A was introduced into the granulator at an introduction rate of 0.46 g / min. Binder A consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. Furthermore, the supporting mixed powder and 12.0 g of binder B were each divided, and the divided supporting mixed powder was introduced alternately first to support the catalyst precursor, which was a molded body. At this time, the ratio of the introduction rate of binder A to the introduction rate of binder B until the entire amount of binder B was introduced was 0.9, the ratio of the introduction rate of binder A to the introduction rate until 90% by mass of binder B was introduced was 0.9, and the ratio of the introduction rate of binder A to the introduction rate until 80% by mass of binder B was introduced was 0.9. Binder B consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. This catalyst precursor was calcined at 390°C for 3 hours in a 3 volume% oxygen atmosphere (air diluted with nitrogen) to obtain a catalyst. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows: Mo 12 V 2.5 W 0.5 Nb 1.0 Cu 1.5 S 0.5 Table 1 shows the results of the gas-phase catalytic oxidation reaction of acrolein using the manufactured catalyst.

[0077] (Example 2) A dried product was obtained in the same manner as in Example 1. This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as the support powder. 1.0 g of flake glass was added to 69.0 g of this support powder and mixed until uniform to obtain a support mixed powder. 100 g of spherical inert carriers with a diameter of 4.5 mm, mainly composed of alumina-silica, were introduced into a rolling granulator, and then 3.0 g of binder A was introduced into the granulator at an introduction rate of 0.40 g / min. Binder A consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. Furthermore, the supporting mixed powder and 12.0 g of binder B were each divided, and the divided supporting mixed powder was introduced alternately first to support the catalyst precursor, which was a molded body. At this time, the ratio of the introduction rate of binder A to the introduction rate of binder B until the entire amount of binder B was introduced was 0.75, the ratio of the introduction rate of binder A to the introduction rate until 90% by mass of binder B was introduced was 0.75, and the ratio of the introduction rate of binder A to the introduction rate until 80% by mass of binder B was introduced was 0.75. Binder B consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. This catalyst precursor was calcined at 390°C for 3 hours in a 3 volume% oxygen atmosphere (air diluted with nitrogen) to obtain a catalyst. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows: Mo 12 V 2.5 W 0.5 Nb 1.0 Cu 1.5 S 0.5 Table 1 shows the results of the gas-phase catalytic oxidation reaction of acrolein using the manufactured catalyst.

[0078] (Example 3) A dried product was obtained in the same manner as in Example 1. This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as the support powder. 1.0 g of flake glass was added to 69.0 g of this support powder and mixed until uniform to obtain a support mixed powder. 100 g of spherical inert carriers with a diameter of 4.5 mm, mainly composed of alumina-silica, were introduced into a rolling granulator, and then 3.0 g of binder A was introduced into the granulator at an introduction rate of 0.30 g / min. Binder A consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. Furthermore, the supporting mixed powder and 12.0 g of binder B were each divided, and the divided supporting mixed powder was introduced alternately first to support the catalyst precursor, which was a molded body. At this time, the ratio of the introduction rate of binder A to the introduction rate of binder B until the entire amount of binder B was introduced was 0.5, the ratio of the introduction rate of binder A to the introduction rate until 90% by mass of binder B was introduced was 0.5, and the ratio of the introduction rate of binder A to the introduction rate until 80% by mass of binder B was introduced was 0.5. Binder B consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. This catalyst precursor was calcined at 390°C for 3 hours in a 3 volume% oxygen atmosphere (air diluted with nitrogen) to obtain a catalyst. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows: Mo 12 V 2.5 W 0.5 Nb 1.0 Cu 1.5 S 0.5 Table 1 shows the results of the gas-phase catalytic oxidation reaction of acrolein using the manufactured catalyst.

[0079] (Example 4) A dried product was obtained in the same manner as in Example 1. This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as the support powder. 1.0 g of flake glass was added to 69.0 g of this support powder and mixed until uniform to obtain a support mixed powder. A tumbling granulator is used to form spherical inert carriers 1 with a diameter of 4.5 mm, mainly composed of alumina-silica. 00g was introduced, and then 3.0g of binder A was introduced into the granulator at an introduction rate of 0.20g / min. Binder A consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. Furthermore, the supporting mixed powder and 12.0 g of binder B were each divided, and the divided supporting mixed powder was introduced alternately first to support the catalyst precursor, which was a molded body. At this time, the ratio of the introduction rate of binder A to the introduction rate of binder B until the entire amount of binder B was introduced was 0.25, the ratio of the introduction rate of binder A to the introduction rate until 90% by mass of binder B was introduced was 0.25, and the ratio of the introduction rate of binder A to the introduction rate until 80% by mass of binder B was introduced was 0.25. Binder B consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. This catalyst precursor was calcined at 390°C for 3 hours in a 3 volume% oxygen atmosphere (air diluted with nitrogen) to obtain a catalyst. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows: Mo 12 V 2.5 W 0.5 Nb 1.0 Cu 1.5 S 0.5 Table 1 shows the results of the gas-phase catalytic oxidation reaction of acrolein using the manufactured catalyst.

[0080] (Example 5) A dried product was obtained in the same manner as in Example 1. This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as the support powder. 1.0 g of flake glass was added to 69.0 g of this support powder and mixed until uniform to obtain a support mixed powder. 100 g of spherical inert carriers with a diameter of 4.5 mm, mainly composed of alumina-silica, were introduced into a rolling granulator, and then 3.0 g of binder A was introduced into the granulator at an introduction rate of 0.30 g / min. Binder A consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. Furthermore, the supporting mixed powder and 12.0 g of binder B were introduced simultaneously in separate states to support the catalyst precursor, which was a molded body. At this time, the ratio of the introduction rate of binder A to the introduction rate of binder B until the entire amount of binder B was introduced was 0.5, the ratio of the introduction rate of binder A to the introduction rate until 90% by mass of binder B was introduced was 0.5, and the ratio of the introduction rate of binder B to the introduction rate until 80% by mass of binder B was introduced was 0.5. Binder B consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. This catalyst precursor was calcined at 390°C for 3 hours in a 3 volume% oxygen atmosphere (air diluted with nitrogen) to obtain a catalyst. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows: Mo 12 V 2.5 W 0.5 Nb 1.0 Cu 1.5 S 0.5 Table 1 shows the results of the gas-phase catalytic oxidation reaction of acrolein using the manufactured catalyst.

[0081] (Comparative Example 1) A dried product was obtained in the same manner as in Example 1. This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as the support powder. 1.0 g of flake glass was added to 69.0 g of this support powder and mixed until uniform to obtain a support mixed powder. 100 g of spherical inert carriers with a diameter of 4.5 mm, mainly composed of alumina-silica, were introduced into a rolling granulator, and then 3.0 g of binder A was introduced into the granulator at an introduction rate of 0.50 g / min. Binder A consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. Furthermore, the supporting mixed powder and 12.0 g of binder B were each divided, and the divided supporting mixed powder was introduced alternately first to support the catalyst precursor, which was a molded body. At this time, the introduction rate of binder A and the amount of binder B introduced were considered. Binder B was introduced in such a way that the ratio of the introduction rate of B to the introduction rate of Binder B was 1.0, the ratio of the introduction rate of Binder A to the introduction rate until 90% by mass of Binder B was introduced was 1.0, and the ratio of the introduction rate of Binder A to the introduction rate until 80% by mass of Binder B was introduced was 1.0. Binder B consisted of glycerin, ammonium sulfate, and water, and was prepared as an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. This catalyst precursor was calcined at 390°C for 3 hours in a 3 volume% oxygen atmosphere (air diluted with nitrogen) to obtain a catalyst. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows: Mo 12 V 2.5 W 0.5 Nb 1.0 Cu 1.5 S 0.5 Table 1 shows the results of the gas-phase catalytic oxidation reaction of acrolein using the manufactured catalyst.

[0082] (Comparative Example 2) A dried product was obtained in the same manner as in Example 1. This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as the support powder. 1.0 g of flake glass was added to 69.0 g of this support powder and mixed until uniform to obtain a support mixed powder. 100 g of spherical inert carriers with a diameter of 4.5 mm, mainly composed of alumina-silica, were introduced into a rolling granulator, and then 3.0 g of binder A was introduced into the granulator at an introduction rate of 0.13 g / min. Binder A consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. Furthermore, the supporting mixed powder and 12.0 g of binder B were each divided, and the divided supporting mixed powder was introduced alternately first to support the catalyst precursor, which was a molded body. At this time, the ratio of the introduction rate of binder A to the introduction rate of binder B until the entire amount of binder B was introduced was 0.07, the ratio of the introduction rate of binder A to the introduction rate until 90% by mass of binder B was introduced was 0.07, and the ratio of the introduction rate of binder A to the introduction rate until 80% by mass of binder B was introduced was 0.07. Binder B consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. This catalyst precursor was calcined at 390°C for 3 hours in a 3 volume% oxygen atmosphere (air diluted with nitrogen) to obtain a catalyst. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows: Mo 12 V 2.5 W 0.5 Nb 1.0 Cu 1.5 S 0.5 Table 1 shows the results of the gas-phase catalytic oxidation reaction of acrolein using the manufactured catalyst.

[0083] (Comparative Example 3) A dried product was obtained in the same manner as in Example 1. This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as the support powder. 1.0 g of flake glass was added to 69.0 g of this support powder and mixed until uniform to obtain a support mixed powder. 100 g of spherical inert carriers with a diameter of 4.5 mm, mainly composed of alumina-silica, were introduced into a rolling granulator, and then 3.0 g of binder A was introduced into the granulator at an introduction rate of 0.13 g / min. Binder A consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. Furthermore, the supporting mixed powder and 12.0 g of binder B were introduced simultaneously in separate states to support the catalyst precursor, which was a molded body. At this time, the ratio of the introduction rate of binder A to the introduction rate of binder B until the entire amount of binder B was introduced was 0.07, the ratio of the introduction rate of binder A to the introduction rate until 90% by mass of binder B was introduced was 0.07, and the ratio of the introduction rate of binder B to the introduction rate until 80% by mass of binder B was introduced was 0.07. Binder B consisted of glycerin, ammonium sulfate, and water, and was an aqueous solution containing 10% by mass of glycerin and 30% by mass of ammonium sulfate. This catalyst precursor was heated at 390°C for 3 hours in a 3 volume% oxygen atmosphere (air diluted with nitrogen). The catalyst was obtained by calcination. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows: Mo 12 V 2.5 W 0.5 Nb 1.0 Cu 1.5 S 0.5 Table 1 shows the results of the gas-phase catalytic oxidation reaction of acrolein using the manufactured catalyst.

[0084] (Comparative Example 4) Table 1 shows the results of the evaluation of the gas-phase catalytic oxidation reaction of acrolein using a catalyst produced by the method described in Example 1 of Japanese Patent Publication No. 2021-146252. Specifically, the experiment was conducted using the following method. 1800 ml of warm water was placed in a container, and 28 g of ammonium paratungstate was added and dissolved. Next, 60 g of ammonium metavanadate was added and dissolved. Then, 454 g of ammonium molybdate was added and dissolved to obtain a solution (hereinafter referred to as "Solution A1"). Next, a solution prepared by dissolving 80g of copper sulfate in 100ml of warm water was added to solution A1 and mixed until uniform. Then, 34g of niobium hydroxide and 13g of antimony trioxide were added to this mixture and stirred to obtain a starting material mixture. This starting material mixture was spray-dried at 150°C, and then heat-treated in air at a heating temperature of 300°C for 1 hour to obtain a dried product.

[0085] This dried material was ground to a particle size of 200 μm or less using a stirring blade type pulverizer to obtain a pulverized material. This pulverized material was used as a support powder. 50.6 g of this support powder was mixed with 1.5% by mass of flaked glass relative to the support powder, and the mixture was heated until uniform to obtain a support powder mixture. 100 g of spherical inert carriers with a diameter of 4.9 mm, mainly composed of alumina-silica, were introduced into a rolling granulator. Subsequently, 21.8% by mass of binder A was introduced into the granulator, out of a total of 14.2 g of binder to be introduced. Binder A was glycerin, in the form of a 10% by mass aqueous solution. Furthermore, the supporting mixed powder and binder B, which constituted 78.2% by mass of the total binder amount of 14.2 g introduced into the granulator, were separated and introduced alternately to support the supporting mixed powder, thereby obtaining a molded catalyst precursor. Binder B was a mixture of glycerin and ammonium sulfate, with a mass ratio of glycerin to ammonium sulfate of 1:3. In addition, binder B was a single aqueous solution, with a glycerin concentration of 10% by mass and an ammonium sulfate concentration of 30% by mass. This catalyst precursor was calcined at 390°C for 3 hours in an atmosphere of 3 volume% oxygen (air diluted with nitrogen) to obtain a catalyst. The composition ratio of the catalytic elemental components of this catalyst (excluding oxygen) was as follows. Mo 12 V 2.4 W 0.5 Nb 1.0 Cu 1.5 S 0.4

[0086] Although not described in Example 1 of Japanese Patent Publication No. 2021-146252, Binder B was introduced such that the ratio of the introduction rate of Binder A to the introduction rate of Binder B until the entire amount of Binder B was introduced was 1.0, the ratio of the introduction rate of Binder A to the introduction rate until 90% by mass of Binder B was introduced was 1.0, and the ratio of the introduction rate until 80% by mass of Binder B was introduced was 1.0. The gas-phase catalytic oxidation reaction of acrolein was carried out using the manufactured catalyst. The evaluation results are shown in Table 1.

[0087] [Table 1]

[0088] As is clear from the above, when acrolein is catalytically oxidized in the gas phase with an oxygen-containing gas using the catalyst obtained by the manufacturing method of the present invention, acrylic acid can be produced in high yield with excellent acrolein conversion rate, high acrylic acid selectivity, and even under conditions of low heat transfer medium temperature. In addition, the powdering rate is low and the mechanical strength is improved. On the other hand, when the ratio (rate ratio) of the introduction rate of binder A (VA) to the introduction rate of binder B (VB80, VB90, VB100) is 0.1 or less, it was found that the pulverization rate is high due to low mechanical strength, making it difficult to use as a practical catalyst. Furthermore, it was found that when the ratio (rate ratio) of the introduction rate of binder A (VA) to the introduction rate of binder B (VB80, VB90, VB100) was 1.0 or higher, the acrolein conversion rate was poor and the acrylic acid yield was not very high under conditions of low heat transfer medium temperature.

Claims

1. A method for producing a catalyst for unsaturated carboxylic acid, comprising a molding step in which a carrier is introduced into a granulator, then a first binder A is introduced, then a powder containing catalyst component elements and a second binder B are introduced, and the powder containing the catalyst component elements is supported on the carrier to form a catalyst precursor, The catalyst component elements include molybdenum (Mo), vanadium (V), and copper (Cu). A method for producing a catalyst for unsaturated carboxylic acid, wherein the ratio of the introduction rate of binder A into the granulator to the introduction rate of binder B (introduction rate of binder A / introduction rate of binder B) is greater than 0.1 and less than 1.

0.

2. A method for producing a catalyst for unsaturated carboxylic acid, comprising a molding step in which a carrier is introduced into a granulator, then a first binder A is introduced, then a powder containing catalyst component elements and a second binder B are introduced, and the powder containing the catalyst component elements is supported on the carrier to form a catalyst precursor, The catalyst component elements include molybdenum (Mo), vanadium (V), and copper (Cu). A method for producing a catalyst for unsaturated carboxylic acid, wherein the ratio of the introduction rate of binder A into the granulator to the introduction rate from the start of introduction of binder B to the completion of introduction of 90% by mass of the total amount of binder B (introduction rate of binder A / introduction rate from the start of introduction of binder B to the completion of introduction of 90% by mass) is greater than 0.1 and less than 1.

0.

3. A method for producing a catalyst for unsaturated carboxylic acid, comprising a molding step in which a carrier is introduced into a granulator, then a first binder A is introduced, then a powder containing catalyst component elements and a second binder B are introduced, and the powder containing the catalyst component elements is supported on the carrier to form a catalyst precursor, The catalyst component elements include molybdenum (Mo), vanadium (V), and copper (Cu). A method for producing a catalyst for unsaturated carboxylic acid, wherein the ratio of the introduction rate of binder A into the granulator to the introduction rate from the start of introduction of binder B to the end of introduction of 80% by mass of the total amount of binder B (introduction rate of binder A / introduction rate from the start of introduction of binder B to the end of introduction of 80% by mass) is greater than 0.1 and less than 1.

0.

4. A method for producing a catalyst for producing an unsaturated carboxylic acid according to any one of claims 1 to 3, wherein the total amount of the binder introduced into the granulator is 5% by mass or more and 30% by mass or less relative to the amount of the carrier introduced into the granulator.

5. A method for producing a catalyst for producing an unsaturated carboxylic acid according to any one of claims 1 to 3, wherein the total amount of the binder introduced into the granulator is 10% by mass or more and 40% by mass or less, relative to the amount of the powder containing the catalyst component element introduced into the granulator.

6. A method for producing a catalyst for producing an unsaturated carboxylic acid according to any one of claims 1 to 3, wherein the binder A and the binder B contain an organic compound.

7. A method for producing a catalyst for producing an unsaturated carboxylic acid according to any one of claims 1 to 3, wherein the amount of binder A introduced into the granulator is 2% by mass or more and 90% by mass or less of the total amount of binder introduced into the granulator, and the amount of binder B introduced into the granulator is 10% by mass or more and 98% by mass or less of the total amount of binder introduced into the granulator.

8. A method for producing an unsaturated carboxylic acid according to any one of claims 1 to 3, wherein the catalytic component element of the catalyst for producing the unsaturated carboxylic acid is represented by the following formula (1). *] １２ . ａ ︸ ｂ u ｃ ﹹ ｄ 3) ｅ : ｆ 3) ｇ 4 ｈ . ｉ () (In formula (1), X represents Nb and / or W, Y represents at least one element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, and Z represents at least one element selected from the group consisting of Fe, Co, Ni, and Bi. a to i represent the atomic ratios of each element, in the range of 0 < a ≤ 12, 0 ≤ b ≤ 12, 0 < c ≤ 12, 0 ≤ d ≤ 8, 0 ≤ e ≤ 500, 0 ≤ f ≤ 500, 0 ≤ g ≤ 500, 0 ≤ h ≤ 500, and i is a value that satisfies the oxidation state of the other elements.)

9. A method for producing acrylic acid, comprising using a catalyst for producing unsaturated carboxylic acids produced by the manufacturing method described in any one of claims 1 to 3, and gas-phase catalytic oxidation of acrolein with an oxygen-containing gas.

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