JP2020015043A - Method fop producing catalyst for producing methacrylic acid - Google Patents

Abstract

To provide a catalyst suitable for producing methacrylic acid with high yield by suppressing decomposition of a methacrolein raw material and methacrylic acid generated in the vapor phase catalytic oxidation reaction of methacrolein, isobutyl aldehyde or isobutyric acid.SOLUTION: There is provided a method for producing a catalyst for producing methacrylic acid containing Mo, V, P and Y as essential active components, which comprises a step of preparing a slurry liquid by mixing a compound containing Mo, a compound containing V, a compound containing P and a compound containing Y at a temperature of 92°C or more.SELECTED DRAWING: None

Description

  The present invention relates to an oxidation catalyst suitable for producing methacrylic acid from methacrolein, isobutyraldehyde or isobutyric acid by a gas phase catalytic oxidation reaction.

  Numerous catalysts have been proposed as catalysts used for producing methacrylic acid by gas phase catalytic oxidation of methacrolein, isobutyraldehyde or isobutyric acid. These catalysts contain molybdenum and phosphorus as main components and have a heteropolyacid and / or a salt thereof structure (for example, Patent Document 1). Further, various improved catalysts have been proposed for efficiently producing methacrylic acid. These improvements mainly involve selection of components constituting the catalyst and their ratio (for example, Patent Documents 2 and 3). However, some of them relate to the specification of the properties of the catalyst (for example, Patent Document 4 and the like) and the method for preparing the catalyst (for example, Patent Document 5 and the like).

  Regarding the catalyst preparation method, in Patent Documents 5 and 6, a catalyst having a desired hetero atom can be produced by changing the type of hetero atom added before and after forming a heteropolyacid salt, and the yield can be improved. I have to.

  However, these conventional catalysts do not always sufficiently satisfy the reaction results in the method for producing methacrylic acid by subjecting methacrolein to gas-phase catalytic oxidation, and at present, further improvement is desired. Various factors can be cited as causes that the reaction results are not sufficiently satisfactory. Among them, the methacrylic acid generated by the catalyst is further decomposed by successive reactions or / and the raw material of methacrolein is directly decomposed. The yield is reduced.

Japanese Patent Application Laid-Open No. 6-91172 Japanese Patent Application Laid-Open No. 9-75740 JP 2013-86008 A Japanese Patent No. 2994706 Japanese Patent No. 5,626,583 Japanese Patent Application Laid-Open No. 2011-224505

  The present invention provides a catalyst suitable for producing methacrylic acid with high yield by suppressing the decomposition of methacrolein raw material and generated methacrylic acid in the gas phase catalytic oxidation reaction of methacrolein, isobutyraldehyde or isobutyric acid. It is intended to be.

  The catalyst of the present invention is a catalyst for producing methacrylic acid containing Mo, V, P, Cu, and Y as essential active components, and has an activation energy (Eaa) determined from an acetone mole generation rate in an isopropyl alcohol dehydration test. It has been found that a catalyst having a ratio of activation energy (Eap) determined from the propylene molar production rate of 0 <(Eaa / Eap) ≦ 2.0 has extremely high catalytic performance, and has completed the present invention. .

That is, the present invention
(1) A catalyst for producing methacrylic acid by a gas-phase catalytic oxidation reaction of methacrolein, isobutyraldehyde or isobutyric acid, wherein the catalytically active component has the general formula (A)
_{Mo 10 V a P b Cu c} X d Y e Z f O g (A)
(Where Mo is molybdenum, V is vanadium, P is phosphorus, Cu is copper, X is at least one element selected from potassium, rubidium, cesium and thallium, Y is arsenic, antimony, germanium, bismuth, cerium and selenium. At least one element selected, Z is at least one element selected from iron, chromium, nickel, cobalt, manganese, magnesium, zinc, tin, silver, palladium, rhodium, ruthenium, tellurium, tungsten, silicon, aluminum, ammonium and boron A to g represent the atomic ratio of each element, a is 0.1 ≦ a ≦ 6.0, b is 0.5 ≦ b <1.4, and c is 0 <c ≦ 3. 0 and d are 0 ≦ d ≦ 3.0, e is 0 <e ≦ 3.0, f is 0 ≦ f ≦ 3.0, and g is the oxidation state and original state of each element. Is a numerical value determined by the ratio)
Wherein the ratio between the activation energy (Eaa) determined by the acetone mole generation rate and the activation energy (Eap) determined by the propylene mole generation rate in the isopropyl alcohol dehydration reaction test is 0 <(Eaa / Eap). Methacrylic acid production catalyst with ≦ 2.0,
(2) A catalyst for producing methacrylic acid by a gas phase catalytic oxidation reaction of methacrolein, isobutyraldehyde or isobutyric acid, wherein the catalytically active component is represented by the general formula (A)
_{Mo 10 V a P b Cu c} X d Y e Z f O g (A)
(Where Mo is molybdenum, V is vanadium, P is phosphorus, Cu is copper, X is at least one element selected from potassium, rubidium, cesium and thallium, Y is arsenic, antimony, germanium, bismuth, cerium and selenium. At least one element selected, Z is at least one element selected from iron, chromium, nickel, cobalt, manganese, magnesium, zinc, tin, silver, palladium, rhodium, ruthenium, tellurium, tungsten, silicon, aluminum, ammonium and boron A to g represent the atomic ratio of each element, a is 0.1 ≦ a ≦ 6.0, b is 0.5 ≦ b <1.4, and c is 0 <c ≦ 3. 0 and d are 0 ≦ d ≦ 3.0, e is 0 <e ≦ 3.0, f is 0 ≦ f ≦ 3.0, and g is the oxidation state and original state of each element. Is a numerical value determined by the ratio)
Wherein the ratio between the activation energy (Eaa) determined by the acetone mole generation rate and the activation energy (Eap) determined by the propylene mole generation rate in the isopropyl alcohol dehydration reaction test is 0 <(Eaa / Eap). Methacrylic acid production catalyst with ≦ 1.0,
(3) In the step of preparing a heteropolyacid aqueous solution or a heteropolyacid aqueous dispersion containing at least molybdenum, vanadium, phosphorus and Y, the total amount of phosphorus and Y is 1.0 mol ≦ (phosphorus + Y ) The catalyst for producing methacrylic acid according to the above (1) or (2), wherein ≦ 1.4 mol;
(4) The catalyst for producing methacrylic acid according to any one of the above (1) to (3), wherein Y is arsenic.
(5) Methacrylic acid that partially oxidizes at least one compound selected from methacrolein, isobutyraldehyde and isobutyric acid in the presence of molecular oxygen using the catalyst according to any one of the above (1) to (4). Manufacturing method,
About.

  In the gas phase catalytic oxidation reaction of methacrolein, isobutyraldehyde or isobutyric acid, it is possible to suppress the decomposition of the methacrolein raw material and the generated methacrylic acid, and provide a catalyst suitable for producing methacrylic acid with a high yield. .

  The present invention is used for producing methacrylic acid by gas phase catalytic oxidation of methacrolein, isobutyraldehyde or isobutyric acid with molecular oxygen, and the catalytically active component is represented by the following general formula (A). It has a composition, and a ratio of an activation energy (Eaa) determined by an acetone mole generation rate in an isopropyl alcohol dehydration reaction test to an activation energy (Eap) determined by a propylene mole generation rate is 0 <(Eaa / Eap) ≦ 2. A catalyst for producing methacrylic acid, which is 0, and a method for producing methacrylic acid by partially oxidizing at least one compound selected from methacrolein, isobutyraldehyde and isobutyric acid in the presence of molecular oxygen using the catalyst.

_{Mo 10 V a P b Cu c} X d Y e Z f O g (A)
In the above general formula (A), Mo is molybdenum, V is vanadium, P is phosphorus, Cu is copper, X is at least one element selected from potassium, rubidium, cesium and thallium, Y is arsenic, antimony, germanium, bismuth. , At least one element selected from cerium and selenium, Z is from iron, chromium, nickel, cobalt, manganese, magnesium, zinc, tin, silver, palladium, rhodium, ruthenium, tellurium, tungsten, silicon, aluminum, ammonium and boron Represents at least one element selected, a to g represent the atomic ratio of each element, a is 0.1 ≦ a ≦ 6.0, b is 0.5 ≦ b <1.4, and c is 0 <C ≦ 3.0, d is 0 ≦ d ≦ 3.0, e is 0 <e ≦ 3.0, f is 0 ≦ f ≦ 3.0, and g is each element. Is a numerical value determined by the oxidation state and atomic ratio.

  In the methacrylic acid production catalyst of the present invention, the ratio of Eaa to Eap is usually 0 <(Eaaa / Eap) ≦ 2.0, preferably 0 <(Eaa / Eap) ≦ 1.0, more preferably 0 <( By satisfying (Eaa / Eap) ≦ 0.9, more preferably 0 <(Eaa / Eap) ≦ 0.8, it is possible to produce methacrylic acid in a high yield in a gas phase contact reaction using methacrolein. enable. This is because the base strength and the base amount of the base point on the catalyst surface which causes the generation of acetone are suppressed with respect to the acid strength and the acid amount of the acid point on the catalyst surface which causes the propylene generation. In addition, it is considered that the decomposition of the generated methacrylic acid can be suppressed.

In the method for producing a catalyst of the present invention, first, a heteropolyacid aqueous solution or a heteropolyacid aqueous dispersion (hereinafter, referred to as a slurry liquid) is prepared by using the total amount of a molybdenum raw material, a vanadium raw material, a phosphorus raw material, and a Y raw material. The temperature at which the slurry liquid is prepared is preferably heated to a temperature at which a compound containing molybdenum, vanadium, phosphorus, Y and, if necessary, other metal elements can be sufficiently dissolved. It is preferable that the total amount of phosphorus and Y serving as raw materials of the central element of the heteropolyacid used is 1.0 mol ≦ (phosphorus + Y) ≦ 1.4 mol per 10 mol of molybdenum atoms. Thereby, a heteropolyacid having a small ionic radius with phosphorus as a central element is preferentially generated, and thereafter, a heteropolyacid with Y as a central element can be generated. When excess Y is present, it can be present as a counter cation of the heteropolyacid. When it is desired to add a part of Y as a counter cation with an arbitrary composition, it is possible to adjust the amount ratio of the central element of the heteropolyacid to the counter cation by adding an amount of the part to the slurry liquid after cooling. It is.

The methacrylic acid production of the present invention is achieved by setting the total amount of phosphorus and Y, which are the raw materials of the central element of the heteropolyacid used, to 1.0 mol ≦ (phosphorus + Y) ≦ 1.4 mol per 10 mol of molybdenum atoms. It is preferable that the ratio of Eaa to Eap in the catalyst for use be 0 <(Eaa / Eap) ≦ 2.0.

  The starting material compound in the catalyst of the present invention is not particularly limited, and is usually a compound containing each element contained in the catalyst, for example, oxo acid, oxo acid salt, oxide, nitrate, carbonate, acetate of each element. , Hydroxide, halide and the like are used in such a ratio as to satisfy a desired atomic ratio. For example, as the compound containing phosphorus, phosphoric acid, phosphate, or the like is used.As the compound containing molybdenum, molybdic acid, molybdate, molybdenum oxide, molybdenum chloride, or the like is used.As the compound containing vanadium, , Vanadic acid, vanadate, vanadium oxide, vanadium chloride and the like are used, and as the compound containing copper, copper nitrate, copper acetate, copper sulfate, copper chloride, copper oxide and the like are used. Further, as the compound containing the element X, oxides, acetates, nitrates, carbonates, hydroxides, halides and the like are used.

  As the compound containing the element Y, an oxide, an acetate, a nitrate, a carbonate, a hydroxide, a halide, or the like is used, and a compound containing arsenic is preferable.

  As the compound containing the element Z, oxo acids, oxo acid salts, nitrates, carbonates, hydroxides, halides and the like are used.

  The compounds containing each element contained in these catalysts may be used alone or in combination of two or more.

  Next, the slurry liquid obtained above is dried to obtain a catalytically active component solid. The drying method is not particularly limited as long as the slurry liquid can be completely dried, and includes, for example, drum drying, freeze drying, spray drying, and evaporation to dryness. The slurry liquid is dried into powder or granules in a short time. Spray drying which can be performed is preferred. The drying temperature of the spray drying varies depending on the concentration of the slurry liquid, the liquid sending speed, and the like, but the temperature at the outlet of the dryer is generally 70 to 150 ° C. Further, it is preferable that the dried slurry liquid obtained at this time is dried so that the average particle diameter thereof is 10 to 700 μm.

  The catalytically active component solid obtained as described above can be used as it is for a coating mixture, but when calcined, moldability may be improved, which is preferable. The firing method and firing conditions are not particularly limited, and known processing methods and conditions can be applied. The optimum conditions for the calcination vary depending on the catalyst raw material, catalyst composition, preparation method and the like to be used, but the calcination temperature is usually 100 to 350 ° C, preferably 150 to 300 ° C, and the calcination time is 1 to 20 hours. The firing is usually performed in an air atmosphere, but may be performed in an inert gas atmosphere such as nitrogen, carbon dioxide, helium, or argon, or may be further performed as necessary after firing in an inert gas atmosphere. The firing may be performed in an air atmosphere.

  Further, in the present invention, the compound containing an active ingredient at the time of preparing the slurry does not necessarily need to contain all the active ingredients, and some of the ingredients may be used before the following coating step.

  The shape of the catalyst of the present invention is not particularly limited, and is used by molding into a column, a tablet, a ring, a sphere or the like in order to reduce the pressure loss of the reaction gas in the oxidation reaction. Among these, it is preferable to coat the inactive carrier with the catalytically active component solid to obtain a coated catalyst because selectivity and removal of reaction heat can be expected. This coating step is preferably a rolling granulation method described below. In this method, for example, in a device having a flat or uneven disk at the bottom of a fixed container, by rotating the disk at a high speed, the carrier in the container is vigorously stirred by repetition of rotation and revolving motion. This is a method in which a carrier is coated with a coating mixture containing a binder, a catalytically active component solid, and, if necessary, other additives such as a molding aid and a strength improver. The method of adding the binder is as follows: 1) preliminarily mixing with the coating mixture, 2) adding the coating mixture into the fixed container at the same time, and 3) adding the coating mixture into the fixed container and then adding it. 4) Addition before adding the coating mixture into the fixed container, 5) Separate the coating mixture and the binder, and appropriately combine 2) to 4) to add the entire amount. . Of these, in 5), for example, the addition rate is adjusted using an auto feeder or the like so that the coating mixture does not adhere to the fixed container wall, and the coating mixture does not agglomerate and a predetermined amount is supported on the carrier. Is preferred. The binder is not particularly limited as long as it is at least one selected from the group consisting of water and an organic compound having a boiling point of 150 ° C. or less at 1 atm or less. Specific examples of binders other than water include alcohols such as methanol, ethanol, propanols and butanols, preferably alcohols having 1 to 4 carbon atoms, ethers such as ethyl ether, butyl ether or dioxane, and esters such as ethyl acetate or butyl acetate. , Acetone or ketones such as methyl ethyl ketone, and aqueous solutions thereof, with ethanol being particularly preferred. When ethanol is used as the binder, it is preferable that ethanol / water = 10/0 to 0/10 (mass ratio), preferably ethanol / water = 9/1 to 1/9 (mass ratio). The amount of the binder to be used is generally 2 to 60 parts by mass, preferably 10 to 50 parts by mass, per 100 parts by mass of the coating mixture.

  Specific examples of the carrier in the coating include a spherical carrier having a diameter of 1 to 15 mm, preferably 2.5 to 10 mm, such as silicon carbide, alumina, silica alumina, mullite, and alundum. These carriers usually have a porosity of 10 to 70%. The ratio of the carrier and the coating mixture is usually such that the coating mixture / (coating mixture + carrier) = 10 to 75% by mass, preferably 15 to 60% by mass. When the proportion of the coating mixture is large, the reaction activity of the coated catalyst increases, but the mechanical strength tends to decrease. Conversely, when the proportion of the coating mixture is small, the mechanical strength is large, but the reaction activity tends to be small. In the above, as a molding aid used as necessary, silica gel, diatomaceous earth, alumina powder and the like can be mentioned. The amount of the molding aid used is usually 1 to 60 parts by mass based on 100 parts by mass of the catalytically active component solid. Further, if necessary, the use of inorganic fibers (for example, ceramics fibers or whiskers) that are inert to the catalytically active component solid and the reaction gas as a strength improver is useful for improving the mechanical strength of the catalyst, Glass fibers are preferred. The amount of these fibers to be used is generally 1 to 30 parts by mass based on 100 parts by mass of the catalytically active component solid.

  The coated catalyst obtained as described above can be directly used as a catalyst in a gas-phase catalytic oxidation reaction, but calcining is preferred because the catalytic activity may be improved. The firing method and firing conditions are not particularly limited, and known processing methods and conditions can be applied. Optimum conditions for calcination vary depending on the catalyst raw material, catalyst composition, preparation method and the like used, but the calcination temperature is usually 100 to 450 ° C, preferably 270 to 420 ° C, and the calcination time is 1 to 20 hours. The firing is usually performed in an air atmosphere, but may be performed in an inert gas atmosphere such as nitrogen, carbon dioxide, helium, or argon, or may be further performed as necessary after firing in an inert gas atmosphere. The firing may be performed in an air atmosphere. The catalyst obtained as described above (hereinafter referred to as the catalyst of the present invention) is used for producing methacrylic acid by subjecting methacrolein, isobutyraldehyde or isobutyric acid to gas-phase catalytic oxidation.

  The activation energy (Eaa) and the activation energy (Eap) of the catalyst of the present invention, which are determined from the acetone mole formation rate in the isopropyl alcohol dehydration reaction test and the propylene mole formation rate, are calculated from the Arrhenius equation shown below. .

(Equation 1) k = A · exp (− (Eaa or Eap) / (RT))

(Where k: reaction rate constant (/ s), A: frequency factor (/ s), Eaa: activation energy (J / mol) determined by the acetone mole formation rate, Eap: activity determined by the propylene mole formation rate Energy (J / mol), R: gas constant (J / (mol · K)), T: absolute temperature (K)

Taking the logarithm of Equation 1 above gives Equation 2 shown below,
(Equation 2) lnk = lnA- (Eaa or Eap) / (RT)
A graph drawn in this format is called an Arrhenius plot. If the plot of lnk and (1 / T) becomes a straight line, the activation energy and the frequency factor can be experimentally obtained using a regression analysis technique.

Assuming that the catalytic reaction is a first-order reaction, the reaction rate constant k shown in Expression 1 holds the following Expression 3 under integral reaction conditions.
(Equation 3) W / F = −ln (1-x) / (k · C)

(Where, W: catalyst amount (kg), F: isopropyl alcohol flow rate (mol / h), x: acetone selectivity or propylene selectivity (−), k: reaction rate constant (m ³ / kg / s), C: isopropyl alcohol initial concentration (mol / m ³ )

  If the plot of W / F and -ln (1-x) / C in Equation 3 becomes a straight line, the reaction rate constant k can be experimentally obtained using a regression analysis technique.

The isopropyl alcohol dehydration reaction is described in Industrial Science Magazine Vol. 69, 1966, no. 12, P2249-2255, Industrial Science Magazine Vol. 73, 1970, no. 8, the reaction apparatus and the reaction conditions as shown in P1886-1888, etc., but the reaction temperature is set to a value suitable for the production of methacrylic acid by gas phase catalytic oxidation of methacrolein, isobutyraldehyde or isobutyric acid. C. to 400C, preferably 230C to 370C. If the reaction temperature exceeds 400 ° C., the catalyst structure may be broken, and an appropriate evaluation result may not be obtained. When the reaction temperature is lower than 200 ° C., a desired reaction does not proceed and an appropriate evaluation result may not be obtained. The supply amount of the raw material gas is, in space velocity (SV), usually 1000 to 150,000 hr ^-1 , preferably 10,000 to 100,000 hr ^-1 . If the space velocity is higher than the above range, the dehydration reaction of isopropyl alcohol does not proceed, and an appropriate evaluation result may not be obtained. Conversely, if the space velocity is lower than the above range, the decomposition of the raw materials and products may proceed. Further, the isopropyl alcohol dehydration reaction can be performed under increased or reduced pressure, but generally, a pressure near the atmospheric pressure is suitable. The shape of the catalyst used in the isopropyl alcohol dehydration reaction test is not particularly limited, but it is preferable to use a catalytically active component solid on the surface of the coated catalyst in order to check the performance of the surface of the coated catalyst.

Hereinafter, the gas phase catalytic reaction using methacrolein which is the most preferable raw material for using the catalyst of the present invention will be described. Molecular oxygen or a molecular oxygen-containing gas is used for the gas phase catalytic oxidation reaction. The use ratio of molecular oxygen to methacrolein is not particularly limited, but the molar ratio is preferably in the range of 0.5 to 20, particularly preferably 1 to 10. For the purpose of allowing the reaction to proceed smoothly, it is preferable to add water to the raw material gas in a molar ratio of 1 to 20 with respect to methacrolein. The raw material gas may contain a gas inert to the reaction such as nitrogen, carbon dioxide gas, saturated hydrocarbon and the like, in addition to oxygen and, if necessary, water (normally included as water vapor). As for methacrolein, a gas obtained by oxidizing isobutylene, tertiary butanol, and methyl tert-butyl ether may be supplied as it is. The reaction temperature is usually 200 to 400 ° C. in a gas phase catalytic oxidation reaction, preferably two hundred and sixty to three hundred and sixty ° C., the supply amount of the raw material gas in the space velocity (SV), usually 100～6000Hr ^-1, preferably 300～3000Hr ^-1 It is. In addition, the gas phase catalytic oxidation reaction can be performed under increased or reduced pressure, but generally, a pressure near the atmospheric pressure is suitable.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.
In the following, the selectivity of acetone and propylene is defined as follows.
Acetone selectivity = moles of acetone produced / moles of reacted isopropyl alcohol × 100
Propylene selectivity = moles of propylene produced / moles of isopropyl alcohol reacted × 100

In the following, the conversion of methacrolein, the selectivity of methacrylic acid and the yield of methacrylic acid are defined as follows.
Conversion of methacrolein = mol of reacted methacrolein / mol of supplied methacrolein × 100
Methacrylic acid selectivity = moles of methacrylic acid formed / moles of reacted methacrolein × 100
Methacrylic acid yield = number of moles of methacrylic acid formed / number of moles of supplied methacrolein x 100

(Isopropyl alcohol dehydration test)
After weighing 0.1 g of the catalytically active component solid on the surface of the coated catalyst, the solid was placed in a fixed-bed circulation furnace, and under an atmosphere of nitrogen, isopropyl alcohol concentration was 1.75%, gas space velocity (GHSV) was 36300 ml / g / h, and 45400 ml. / G / h, 90800 ml / g / h, reaction bath temperature 250 ° C, 300 ° C, 350 ° C. The reaction products were qualitatively and quantitatively determined by gas chromatography. Based on the acetone selectivity and propylene selectivity obtained from these various conditions, -ln (1-x) is plotted on the vertical axis and W / F is plotted on the horizontal axis, and the reaction rate constant k is experimentally determined from the slope. I asked. From the obtained reaction rate constant k, lnk was plotted on the ordinate and 1 / T was plotted on the abscissa (Arrhenius plot), and the activation energies of acetone and propylene were determined from the slope.

(Catalyzed oxidation reaction of methacrolein)
41.2 ml of the obtained coated catalyst was filled in a stainless steel reaction tube having an inner diameter of 18.4 mm, and a raw material gas (composition (molar ratio); methacrolein: oxygen: water vapor: nitrogen = 1: 2: 4: 18.6) was used. Under the conditions of a gas space velocity of 300 hr ^-1 , three to four-point reaction results were measured in a desired temperature range including a temperature at which the conversion of methacrolein became 77% after 24 hours from the start of the reaction. The reaction products were qualitatively and quantitatively determined by gas chromatography. The reaction evaluation was performed by calculating the methacrylic acid selectivity at a methacrolein conversion rate of 77% obtained from the above measurement.

Example 1
After adding 800 g of molybdenum trioxide, 30.33 g of vanadium pentoxide, 70.47 g of 85% by mass orthophosphoric acid and 39.44 g of an aqueous solution of 60% by mass diarsenic pentoxide to 5680 ml of pure water, and heating and stirring at 92 ° C. for 1 hour, 300 g of a 30% by mass aqueous hydrogen peroxide solution was added, followed by heating and stirring for 2 hours to obtain a red-brown transparent solution. Subsequently, the solution was cooled to 0 to 20 ° C., and 661.32 g of a 9.1 mass% cesium hydroxide aqueous solution was gradually added thereto with stirring, and the mixture was aged for 1 hour after the addition. Subsequently, 196.86 g of a 50.0% by mass aqueous ammonium acetate solution was gradually added with stirring, and the mixture was aged at 0 ° C to 30 ° C for 1 hour. Subsequently, 22.18 g of cupric acetate was further added to the slurry, and the mixture was stirred and mixed at 0 to 30 ° C. until completely dissolved. Subsequently, the slurry was spray-dried to obtain a catalytically active component solid. The composition of the solid of the catalytically active component determined from the charged amounts of the raw materials is Mo ₁₀ V _0.6 P _1.1 As _0.3 Cs _0.7 (NH ₄ ) _2.3 Cu _0.2
It is. Next, 120 g of the catalytically active component solid and 6.5 g of the strength improving material (glass fiber) are uniformly mixed, and coated and molded with 200 g of a spherical porous alumina carrier (4.5 mm in particle diameter) using about 30 g of a 50% by mass aqueous ethanol solution as a binder. did. Next, the obtained molded product was calcined at 380 ° C. for 5 hours under a flow of air to obtain Catalyst 1 of the present invention. It is considered that the composition of the active ingredient after the calcination is reduced to about 0.01 to 1.0 because most of the ammonia component is lost by the calcination. Table 1 summarizes the reaction results of the catalytic oxidation reaction of Eaa / Eap and methacrolein calculated from the activation energies determined from the acetone mole formation rate and the activation energy determined from the propylene mole formation rate of the obtained catalyst. .

Example 2
Catalyst 2 of the present invention was prepared in the same manner as in Example 1 except that the catalytically active component solid was preliminarily calcined at 200 ° C. before coating molding in Example 1. Table 1 summarizes the reaction results of the catalytic oxidation reaction of Eaa / Eap and methacrolein calculated from the activation energies determined from the acetone mole formation rate and the activation energy determined from the propylene mole formation rate of the obtained catalyst. .

Example 3
A catalyst 3 of the present invention was prepared in the same manner as in Example 2 except that a solid of catalytically active component was obtained without adding 30% by mass of aqueous hydrogen peroxide in Example 2. Table 1 summarizes the reaction results of the catalytic oxidation reaction of Eaa / Eap and methacrolein calculated from the activation energies determined from the acetone mole formation rate and the activation energy determined from the propylene mole formation rate of the obtained catalyst. .

Example 4
Catalyst 4 of the present invention was prepared in the same manner as in Example 1, except that 196.86 g of the 50.0% by mass aqueous ammonium acetate solution was changed to 162.62 g of the 50.0% by mass aqueous ammonium acetate solution in Example 1. . The composition of the catalytically active component solid determined from the charged raw material amount is Mo ₁₀ V _0.6 P _1.1 As _0.3 Cs _0.7 (NH ₄ ) _1.9 Cu _0.2.
It is. Table 1 summarizes the reaction results of the catalytic oxidation reaction of Eaa / Eap and methacrolein calculated from the activation energies determined from the acetone mole formation rate and the activation energy determined from the propylene mole formation rate of the obtained catalyst. .

Comparative Example 1
800 g of molybdenum trioxide, 30.33 g of vanadium pentoxide, and 76.87 g of 85 mass% orthophosphoric acid were added to 6400 ml of pure water, and the mixture was heated and stirred at 92 ° C. for 3 hours to obtain a reddish brown transparent solution. Subsequently, the solution was cooled to 0 to 20 ° C., and 944.31 g was collected in another container (Solution A). The remainder at this time is referred to as solution B. Thereafter, 661.32 g of a 9.1 mass% cesium hydroxide aqueous solution was gradually added to the solution A while stirring, and the mixture was aged for 4 hours after the addition. Subsequently, the solution B was added to the slurry, and 13.15 g of a 60% by mass aqueous solution of diarsenic pentoxide was further added. Subsequently, 196.86 g of a 50.0% by mass aqueous ammonium acetate solution was gradually added with stirring, and the mixture was aged at 0 ° C to 30 ° C for 1 hour. Subsequently, 22.18 g of cupric acetate was further added to the slurry, and the mixture was stirred and mixed at 0 to 30 ° C. until completely dissolved. Subsequently, the slurry was spray-dried to obtain a catalytically active component solid. The composition of the catalytically active component solid determined from the raw material charge amount is Mo ₁₀ V _0.6 P _1.1 As _0.1 Cs _0.7 (NH ₄ ) _2.3 Cu _0.2
It is. Next, 120 g of the catalytically active component solid and 6.5 g of the strength improving material (glass fiber) are uniformly mixed, and coated and molded with 200 g of a spherical porous alumina carrier (4.5 mm in particle diameter) using about 30 g of a 50% by mass aqueous ethanol solution as a binder. did. Next, the obtained molded product was calcined at 380 ° C. for 5 hours under air flow to obtain a comparative catalyst 5. It is considered that the composition of the active ingredient after the calcination is reduced to about 0.01 to 1.0 because most of the ammonia component is lost by the calcination. Table 1 summarizes the reaction results of the catalytic oxidation reaction of Eaa / Eap and methacrolein calculated from the activation energies determined from the acetone mole formation rate and the activation energy determined from the propylene mole formation rate of the obtained catalyst. .

Comparative Example 2
A comparative catalyst 6 was prepared in the same manner as in Comparative Example 1, except that 13.15 g of the 60% by weight aqueous solution of diarsenic pentoxide was changed to 13.94 g of the 60% by weight aqueous solution of diarsenic pentoxide. The composition of the solid of the catalytically active component determined from the charged amounts of the raw materials is Mo ₁₀ V _0.6 P _1.1 As _0.3 Cs _0.7 (NH ₄ ) _2.3 Cu _0.2
It is. Table 1 summarizes the reaction results of the catalytic oxidation reaction of Eaa / Eap and methacrolein calculated from the activation energies determined from the acetone mole formation rate and the activation energy determined from the propylene mole formation rate of the obtained catalyst. .

Comparative Example 3
1000 g of molybdenum trioxide, 44.23 g of vanadium pentoxide, 88.11 g of 85 mass% orthophosphoric acid, 11.05 g of copper oxide, and 82.18 g of a 60 wt% diarsenic pentoxide aqueous solution were added to 7100 ml of pure water. After heating and stirring for a period of time, a reddish brown transparent solution was obtained. Subsequently, the slurry was spray-dried to obtain a catalytically active component solid. The composition of the catalytically active component solid determined from the raw material charge amount is Mo ₁₀ V _0.7 P _1.1 As _0.5 Cu _0.2
It is. Then, 320 g of the catalytically active component solid and 55 g of the strength improving material (glass fiber) were uniformly mixed, and 300 g of a spherical porous alumina carrier (3.5 mm in particle diameter) was coated and molded with about 75 g of a 90% by mass aqueous ethanol solution as a binder. Then, the obtained molded product was calcined at 310 ° C. for 5 hours under air flow to obtain a comparative catalyst 7. Table 1 summarizes the reaction results of the catalytic oxidation reaction of Eaa / Eap and methacrolein calculated from the activation energies determined from the acetone mole formation rate and the activation energy determined from the propylene mole formation rate of the obtained catalyst. .

Comparative Example 4
800 g of molybdenum trioxide, 40.43 g of vanadium pentoxide, and 73.67 g of 85% by mass orthophosphoric acid were added to 5680 ml of pure water, and the mixture was stirred with heating at 92 ° C. for 3 hours to obtain a reddish brown transparent solution. Subsequently, the solution was cooled to 0-20 ° C. Thereafter, 317.46 g of a 9.1 mass% cesium hydroxide aqueous solution and 196.86 g of a 50.0 mass% ammonium acetate aqueous solution were gradually added while stirring, and the mixture was aged at 0 ° C. to 30 ° C. for 1 hour. Subsequently, 44.37 g of cupric acetate was further added to the slurry, and the mixture was stirred and mixed at 0 to 30 ° C. until completely dissolved. Subsequently, the slurry was spray-dried to obtain a catalytically active component solid. Next, 120 g of a catalytically active component solid, 8.34 g of antimony trioxide, and 6.5 g of a strength improving material (glass fiber) were uniformly mixed, and 200 g of a spherical porous alumina carrier (particle size: 4.5 mm) was added to a 50 mass% aqueous ethanol solution. Approximately 30 g was coated and molded using a binder. Next, the obtained molded product was calcined at 380 ° C. for 5 hours in a flowing air to obtain a catalyst 8 for comparison. It is considered that the composition of the active ingredient after the calcination is reduced to about 0.01 to 1.0 because most of the ammonia component is lost by the calcination. The composition of the solid of the catalytically active component determined from the charged amount of the raw material is Mo ₁₀ V _0.8 P _1.15 Cs _0.34 (NH ₄ ) _2.3 Cu _0.4 Sb _1.0.
It is. Table 1 summarizes the reaction results of the catalytic oxidation reaction of Eaa / Eap and methacrolein calculated from the activation energies determined from the acetone mole formation rate and the activation energy determined from the propylene mole formation rate of the obtained catalyst. .

Although the present invention has been described in detail with reference to particular embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application (2015-0455539) filed on March 9, 2015, which is incorporated by reference in its entirety. Also, all references cited herein are incorporated in their entirety.

In the gas-phase catalytic oxidation reaction of methacrolein, isobutyraldehyde or isobutyric acid, it is possible to provide a catalyst suitable for producing methacrylic acid in a high yield by suppressing the decomposition of methacrolein raw material and generated methacrylic acid. .

Claims (2)

A catalyst for producing methacrylic acid from methacrolein, isobutyraldehyde or isobutyric acid by a gas phase catalytic oxidation reaction, wherein the catalytically active component is represented by the general formula (A)
_{Mo 10 V a P b Cu c} X d Y e Z f O g (A)
(Where Mo is molybdenum, V is vanadium, P is phosphorus, Cu is copper, X is at least one element selected from potassium, rubidium, cesium and thallium, Y is arsenic, antimony, germanium, bismuth, cerium and selenium. At least one element selected, Z is at least one element selected from iron, chromium, nickel, cobalt, manganese, magnesium, zinc, tin, silver, palladium, rhodium, ruthenium, tellurium, tungsten, silicon, aluminum, ammonium and boron A to g represent the atomic ratio of each element, a is 0.1 ≦ a ≦ 6.0, b is 0.5 ≦ b <1.4, and c is 0 <c ≦ 3. 0 and d are 0 ≦ d ≦ 3.0, e is 0 <e ≦ 3.0, f is 0 ≦ f ≦ 3.0, and g is the oxidation state and original state of each element. Is a numerical value determined by the ratio.)
Wherein the ratio between the activation energy (Eaa) determined by the acetone mole generation rate and the activation energy (Eap) determined by the propylene mole generation rate in the isopropyl alcohol dehydration reaction test is 0 <(Eaa / Eap). A method for producing a catalyst for producing methacrylic acid, which satisfies ≦ 2.0, wherein the compound containing Mo, the compound containing V, the compound containing P and the compound containing Y in the above general formula (A) are represented by the following formula: A method for producing a catalyst for producing methacrylic acid, comprising a step of preparing a slurry liquid by mixing at a temperature of at least ℃. In the step of mixing the Mo-containing compound, the V-containing compound, the P-containing compound and the Y-containing compound at a temperature of 92 ° C. or higher to prepare a slurry liquid, the total amount of phosphorus and Y becomes molybdenum. The method for producing a catalyst for producing methacrylic acid according to claim 1, wherein 1.0 mol ≤ (phosphorus + Y) ≤ 1.4 mol per 10 mol of atoms .