Catalyst, method for producing catalyst, and method for producing unsaturated carboxylic acid and / or unsaturated carboxylic acid ester

Abstract

The purpose of the present invention is to provide a catalyst capable of producing, with high selectivity, an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester represented by methyl methacrylate. Provided is a catalyst that contains: one or more elements selected from among boron, magnesium, zirconium, hafnium, and titanium; one or more elements selected from among alkali metal elements; and silica. The problem to be addressed is solved by using this catalyst, which has a 0 to 1.2 peak height ratio of I2 / I1 where the peak height at 417±10 cm-1 is denoted by I1, and the peak height at 1,050±10 cm-1 is denoted by I2, the peak heights obtained by using Raman spectroscopic analysis.

Description

Catalyst, method for producing catalyst, and method for producing unsaturated carboxylic acid and / or unsaturated carboxylic acid ester

[0001] The present invention relates to a catalyst, a method for producing the catalyst, and a method for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester.

[0002] Methyl methacrylate is an extremely useful substance used as a raw material for various types of polymers with various applications. Numerous methods for industrially producing methyl methacrylate have been investigated, including the acetone cyanohydrin process and direct oxidation using C4 raw materials. In recent years, a production process known as the Alpha Process has attracted attention. Generally, the Alpha Process consists of a first-stage reaction to produce methyl propionate using ethylene as a raw material, and a second-stage reaction to produce methyl methacrylate through an aldol condensation reaction of the resulting methyl propionate. In the Alpha Process for producing methyl methacrylate, improving the selectivity of methyl methacrylate in the second-stage reaction is a particular challenge, and various catalysts have been investigated.

[0003] For example, Patent Document 1 proposes a catalyst for the downstream reaction in the Alpha process, which contains porous high surface area silica containing 1 to 10 mass % of an alkali metal and a specific amount of a compound of at least one modifier element selected from boron, magnesium, aluminum, zirconium, and hafnium.

[0004] Patent Document 2 proposes a catalyst obtained by supporting at least one modifying metal selected from zirconium or hafnium as one or two metal atoms on a carrier and calcining the resulting carrier.

[0005] Patent Document 3 proposes a catalyst obtained by supporting at least one modifying metal selected from boron, magnesium, aluminum, zirconium, hafnium, and titanium as one or two metal atoms on a carrier, further supporting a catalytic metal element, and then calcining the resulting carrier.

[0006] Patent Publication No. 2002-511336 International Publication No. 2019 / 53438 International Publication No. 2020 / 183193

[0007] However, even when the catalysts described in Patent Documents 1 to 3 are used, the selectivity for methyl methacrylate is insufficient, and it is therefore desirable industrially to produce methyl methacrylate with a higher selectivity. That is, an object of the present invention is to provide a catalyst capable of producing unsaturated carboxylic acid esters, such as methyl methacrylate, and unsaturated carboxylic acids with a high selectivity.

[0008] The present invention has been made in view of the above circumstances, and the inventors have discovered that the above problems can be solved by using a catalyst that provides a specific peak intensity ratio as determined by Raman spectroscopy, thereby achieving the present invention.

[0009] That is, the gist of the present invention is as follows: [1]: A catalyst containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium, one or more elements Y selected from alkali metal elements, and silica, wherein the catalyst has a Raman spectroscopic analysis of 417±10 cm －１ The maximum peak height at I １ , 1050±10cm －１ The maximum peak height at I ２ When the peak height ratio I ２ / I １ [2]: The catalyst I ２ / I １The catalyst according to [1], wherein the value of X is 0 to 0.5. [3]: The catalyst according to [1] or [2], which is a catalyst for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester. [4]: ​​The catalyst according to any one of [1] to [3], wherein the element X contains zirconium. [5]: The catalyst according to any one of [1] to [4], wherein the content of the element X is 0.3 to 10 mass% with respect to the mass of the entire catalyst. [6]: The catalyst according to any one of [1] to [5], wherein the element Y contains cesium. [7]: The catalyst according to any one of [1] to [6], wherein the content of the element Y is 3 to 25 mass% with respect to the mass of the entire catalyst. [8]: The catalyst according to any one of [1] to [7], wherein the molar ratio MY / MX is 1.3 to 8, where MX is the number of moles of the element X and MY is the number of moles of the element Y. [9]: The catalyst according to any one of [1] to [7], wherein the BET specific surface area is 50 to 600 m ２The catalyst according to any one of [1] to [8], wherein the catalytic activity is / g.

[10] : A method for producing a catalyst, comprising: (1) a step of impregnating a silica-containing carrier with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain a solid component A, (2) a step of heat-treating the solid component A to obtain a solid component B, (3) a step of impregnating the solid component B with a solution or dispersion (liquid B) containing one or more elements Y selected from alkali metal elements to obtain a solid component C, and (4-1) a step of heat-treating the solid component C at a heat treatment temperature of 100 to 300°C to obtain a catalyst, wherein in the step (2), the solid component A is heat-treated at a heat treatment temperature of 150 to 300°C for 15 minutes to 24 hours.

[11] : The method for producing a catalyst according to

[10] , wherein in the step (2), the rate of temperature rise from when the solid content A reaches 120°C to when it reaches the heat treatment temperature is 10°C / min or less.

[12] : The method for producing a catalyst according to

[10] or

[11] , wherein in the step (4-1), the solid content C is heat-treated for 15 minutes to 24 hours.

[13] : A method for producing a catalyst, comprising: (1) impregnating a silica-containing carrier with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain solid content A, (2) heat-treating the solid content A to obtain solid content B, (3) impregnating the solid content B with a solution or dispersion (liquid B) containing one or more elements Y selected from alkali metal elements to obtain solid content C, and (4-2) heat-treating the solid content C at a heat treatment temperature of 400 to 450°C to obtain a catalyst, wherein in the step (4-2), the rate of temperature rise of the solid content C from 120°C to the heat treatment temperature is 10°C / min or less.

[14] : A method for producing a catalyst according to

[13] , wherein the solid content C is heat-treated for 3 to 24 hours in the step (4-2).

[15] : In the step (4-2), the heating rate from when the solid content C reaches 120°C to when it reaches the heat treatment temperature is 2 to 8°C / min.

[16] The method for producing a catalyst according to

[13] or

[14] .

[16] : A method for producing a catalyst, comprising: (1) impregnating a silica-containing carrier with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain solid content A, (2) heat-treating the solid content A to obtain solid content B, (3) impregnating the solid content B with a solution or dispersion (liquid B) containing one or more elements Y selected from alkali metal elements to obtain solid content C, and (4-3) heat-treating the solid content C at a heat treatment temperature of more than 450°C and not more than 700°C to obtain a catalyst, wherein in the step (4-3), the rate of temperature rise from when the solid content C reaches 120°C to when it reaches the heat treatment temperature is 10°C / min or less.

[17] : A method for producing a catalyst according to

[16] , wherein in the step (4-3), the solid content C is heat-treated for 15 minutes to 24 hours.

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

[16] or

[17] , wherein in the step (4-3), the rate of temperature rise from when the solid content C reaches 120°C until when it reaches the heat treatment temperature is 2 to 8°C / min.

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

[13] to

[18] , wherein in the step (2), the solid content A is heat-treated at a heat treatment temperature of 100 to 200°C.

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

[13] to

[19] , wherein in the step (2), the solid content A is heat-treated for 15 minutes to 24 hours.

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

[10] to

[20] , wherein the catalyst is a catalyst for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester.

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

[10] to

[21] , wherein in the step (1), the element X contains zirconium.

[23] : The method for producing a catalyst according to any of

[10] to

[22] , wherein in the step (3), the element Y contains cesium.

[24] : A method for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester, comprising producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester from a carboxylic acid and / or a carboxylic acid ester and formaldehyde using the catalyst according to any one of [1] to [9].

[25] : A method for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester, comprising producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester from a carboxylic acid and / or a carboxylic acid ester and formaldehyde using a catalyst produced by the method for producing a catalyst according to any one of

[10] to

[23] .

[0010] According to the present invention, it is possible to provide a catalyst that enables the production of a target product, particularly an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester, with high selectivity, and a method for producing the catalyst. It is also possible to provide a method for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester with high selectivity using the catalyst.

[0011] The peak height ratio I obtained by Raman spectroscopy of the catalyst according to the embodiment of the present invention ２ / I １ 1 is a graph showing the relationship between the catalyst content and the selectivity for methacrylic acid and methyl methacrylate when methacrylic acid and methyl methacrylate are produced using the catalyst.

[0012] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less.

[0013] [Catalyst] One embodiment of the present invention is a catalyst containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium, one or more elements Y selected from alkali metal elements, and silica, wherein the catalyst has a Raman spectroscopic analysis of 417±10 cm －１ The maximum peak height at I １ , 1050±10cm －１ The maximum peak height at I ２ When the peak height ratio I ２ / I １ is 0 to 1.2. There is no particular limitation on the shape of the catalyst, and examples thereof include a spherical, columnar, or ring shape.

[0014] <Raman spectroscopic analysis of catalyst> In the Raman spectroscopic analysis of the catalyst, －１ The peak at 1050 ± 10 cm is due to the structure of the active site of the main reaction. －１ The peak at is presumed to be due to the structure of the active site of the side reaction.

[0015] Peak height ratio I ２ / I １ When the ratio is 0 to 1.2, the catalyst has a reduced number of active sites for side reactions and the active sites for the main reaction are moderately highly dispersed, which is thought to improve the selectivity of the target product. ２ / I １ The upper limit of the value of is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.3 or less. ２ / I １ A catalyst having the above range can be obtained, for example, by adjusting the heat treatment temperature in the production of the catalyst. In particular, it is preferable to use a method in which solid components A and C are heat treated under the conditions described in the catalyst production method described below.

[0016] In the present invention, Raman spectroscopy is performed using a laser Raman spectroscopy device at an excitation wavelength of 488 nm. As the laser Raman spectroscopy device, for example, a 3D microscopic laser Raman spectroscopy device Nanofinder (manufactured by Tokyo Instruments Inc.) can be used. ２ / I １ The Raman spectroscopic analysis is carried out at five points on the cross section of the catalyst divided into two, changing the measurement location at regular intervals from one end to the other. －１ Minimum strength at 867±2cm －１ The baseline correction is performed using the line connecting the minimum intensities at 417±10 cm. －１ The length of the perpendicular line from the peak top to the baseline at １ Also, 1050±10cm －１The length of the perpendicular line from the peak top to the line drawn between both ends of the peak is I ２ The above procedure is carried out for the five points analyzed, and the arithmetic mean value is calculated as I １ , I ２ and I ２ / I １ Calculate.

[0017] <Catalyst Constituent Elements> The catalyst of this embodiment contains one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium. The element X preferably contains boron or zirconium, and more preferably contains zirconium. The element X may contain one or more elements. From the viewpoint of improving the selectivity of the target product, the lower limit of the content of element X relative to the total mass of the catalyst is preferably 0.3 mass% or more, more preferably 0.5 mass% or more, even more preferably 1 mass% or more, and particularly preferably 1.5 mass% or more. The upper limit is preferably 10 mass% or less, more preferably 6 mass% or less, even more preferably 5 mass% or less, and particularly preferably 4 mass% or less.

[0018] The catalyst of this embodiment also contains one or more elements Y selected from alkali metal elements. The element Y preferably contains lithium, sodium, potassium, rubidium, or cesium, more preferably contains potassium, rubidium, or cesium, and even more preferably contains cesium. The element Y may contain one type or two or more types. From the viewpoint of improving the selectivity of the target product, the lower limit of the content of the element Y relative to the total mass of the catalyst is preferably 3% by mass or more, more preferably 4% by mass or more, and even more preferably 6% by mass or more. The upper limit is preferably 25% by mass or less, more preferably 18% by mass or less, even more preferably 14% by mass or less, and particularly preferably 12% by mass or less.

[0019] When the number of moles of the element X is MX and the number of moles of the element Y is MY, from the viewpoint of improving the selectivity of the target product, the lower limit of the molar ratio MY / MX is preferably 1.3 or more, more preferably 1.5 or more, even more preferably 1.7 or more, and particularly preferably 1.9 or more. The upper limit is preferably 8 or less, more preferably 6 or less, even more preferably 5.5 or less, and particularly preferably 5 or less. The contents of the elements X and Y can be measured by X-ray fluorescence analysis. The molar ratio MY / MX can be calculated from the obtained contents of the elements X and Y. The X-ray fluorescence analysis is performed, for example, using a ZSX Primus IV (manufactured by Rigaku Corporation) under a helium atmosphere.

[0020] The catalyst of this embodiment also contains silica. In the catalyst, silica functions as a support. The support may further contain alumina, zeolite, titania, zirconia, or the like in addition to silica.

[0021] The catalyst of this embodiment may also contain other metal elements in addition to those described above. Examples of other metal elements include iron. From the viewpoint of suppressing a decrease in the selectivity of the target product, the upper limit of the content of other metal elements is preferably 1 mass% or less, more preferably 0.5 mass% or less, and even more preferably 0.2 mass% or less, relative to the mass of the entire catalyst. The catalyst of this embodiment may also contain other elements derived from the catalyst production process.

[0022] <BET specific surface area of ​​catalyst> The lower limit of the BET specific surface area of ​​the catalyst is 50 m from the viewpoint of improving the selectivity of the target product. ２ / g or more, and ２ / g or more is more preferable, and 100m ２ / g or more is more preferable. ２ / g or less, and ２ / g or less is more preferable, and 350m ２ / g or less is more preferable, and 300m ２The BET specific surface area is particularly preferably 1 / g or less. The BET specific surface area is calculated by the BET single-point method using a nitrogen adsorption measurement device. As the nitrogen adsorption measurement device, for example, Macsorb (manufactured by Mountech Co., Ltd.) can be used.

[0023] [Catalyst Production Method 1] A first embodiment of the catalyst production method of the present invention comprises the following steps: (1) a step of impregnating a silica-containing carrier with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain solid content A; (2) a step of heat-treating solid content A to obtain solid content B; (3) a step of impregnating solid content B with a solution or dispersion (liquid B) containing one or more elements Y selected from alkali metal elements to obtain solid content C; (4-1) a step of heat-treating solid content C at a heat treatment temperature of 100 to 300°C to obtain a catalyst. Furthermore, in the first embodiment of the catalyst production method of the present invention, in step (2), solid content A is heat-treated at a heat treatment temperature of 150 to 300°C for 15 minutes to 24 hours.

[0024] Each step will be described in detail below. <Step (1)> In step (1), a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium is impregnated into a carrier containing silica to obtain a solid content A.

[0025] (Solution A) Solution A can be obtained by dissolving or dispersing a compound containing element X in a solvent. At this time, the compound containing element X may be dissolved or dispersed while stirring the solvent. Element X preferably contains boron or zirconium, and more preferably contains zirconium. Element X may be one type or two or more types. The compound containing element X is preferably an inorganic salt of element X. The compound containing element X is preferably an inorganic salt of element X. The inorganic salt is not particularly limited as long as it is an inorganic compound that does not contain hydrocarbons, and examples thereof include carbonates, nitrates, oxynitrates, sulfates, acetates, ammonium salts, oxides, and halides. These can be used alone or in combination. More specifically, when element X is boron, examples include boron oxide. When element X is magnesium, examples include magnesium nitrate, magnesium sulfate, magnesium carbonate, and magnesium acetate. When the element X is zirconium, examples of the nitrate include zirconium oxynitrate, zirconium nitrate, zirconium sulfate, zirconium carbonate, zirconium perchlorate, and zirconium acetate, and zirconium oxynitrate is preferred.When the element X is hafnium, examples of the nitrate include hafnium nitrate, hafnium sulfate, hafnium perchlorate, and hafnium acetate.When the element X is titanium, examples of the nitrate include titanium oxide, titanium chloride, and titanyl sulfate.

[0026] From the viewpoint of improving the selectivity of the target product, the content of element X in the obtained catalyst is preferably 0.3 mass% or more, more preferably 0.5 mass% or more, even more preferably 1 mass% or more, and particularly preferably 1.5 mass% or more, relative to the mass of the entire catalyst. The upper limit is preferably 10 mass% or less, more preferably 6 mass% or less, even more preferably 5 mass% or less, and particularly preferably 4 mass% or less. The content of element X can be adjusted by the amount of element X charged.

[0027] The solvent is not particularly limited, and examples thereof include water or an organic solvent. The organic solvent is preferably an alcohol, more preferably an alcohol having 1 to 6 carbon atoms, still more preferably an alcohol having 1 to 3 carbon atoms, particularly preferably an alcohol having 1 to 2 carbon atoms, and most preferably methanol.

[0028] The amount of the compound containing element X contained in solution A is not particularly limited, but from the viewpoint of uniformly dispersing element X, the lower limit is preferably 2 mmol or more, more preferably 5 mmol or more, and even more preferably 10 mmol or more relative to 100 mL of solvent. From the viewpoint of suppressing re-aggregation of element X, the upper limit is preferably 60 mmol or less, more preferably 50 mmol or less, and even more preferably 40 mmol or less relative to 100 mL of solvent.

[0029] (Carrier) The carrier to be impregnated with the solution A contains silica and may further contain alumina, zeolite, titania, zirconia, etc. As the silica, silica gel is preferably used. From the viewpoint of improving the selectivity of the target product, the lower limit of the BET specific surface area of ​​the carrier is 50 m ２ / g or more, and ２ / g or more is more preferable, and 100m ２ / g or more is more preferable. ２ / g or less, and ２ / g or less is more preferable, and 350m ２ / g or less is more preferable, and 300m ２ / g or less is particularly preferred. There are no particular limitations on the method for adjusting the BET specific surface area of ​​the carrier, but for example, a carrier having pores that allow a desired BET specific surface area to be obtained can be used. If the carrier has a high pore ratio, the BET specific surface area tends to be large, and if the carrier has a low pore ratio, the BET specific surface area tends to be small. The BET specific surface area is measured by the BET single-point method using a nitrogen adsorption measurement device. As the nitrogen adsorption measurement device, for example, a Macsorb (manufactured by Mountech Co., Ltd.) can be used.

[0030] The shape of the carrier is not particularly limited, and examples thereof include powder, granules, pellets, and tablets. There is no particular limit to the average particle size of the carrier, but from the viewpoint of suppressing pressure loss in the reaction for producing the target product, the lower limit is preferably 500 μm or more, more preferably 1 mm or more, and even more preferably 1.3 mm or more. In addition, from the viewpoint of suppressing the progression of side reactions, the upper limit is preferably 10 mm or less, more preferably 6 mm or less, and even more preferably 5 mm or less. There is no particular limit to the average pore diameter of the carrier, but from the viewpoint of suppressing the progression of side reactions, the lower limit is preferably 3 nm or more, more preferably 5 nm or more, and even more preferably 7 nm or more. In addition, from the viewpoint of maintaining the BET specific surface area, the upper limit is preferably 200 nm or less, more preferably 150 nm or less, even more preferably 100 nm or less, and particularly preferably 50 nm or less. It is preferable that the carrier be calcined to remove moisture before impregnating with liquid A. Furthermore, it is preferable that the support after calcination is stored in a desiccator, in dry air, or in a dry inert gas, and maintained in a state where moisture is removed.

[0031] (Impregnation of the support with Liquid A) There are no particular limitations on the method for impregnating the support with Liquid A, and known methods can be used. For example, there are pore filling methods in which Liquid A is added to the support in an amount equal to the pore volume of the support, and immersion methods in which the support is immersed in Liquid A. There are no particular limitations on the time for impregnating the support with Liquid A, but from the viewpoint of successfully impregnating the support with element X, the lower limit is preferably 15 minutes or more, and more preferably 1 hour or more. Furthermore, from the viewpoint of the time required for catalyst production, the upper limit is preferably 50 hours or less, more preferably 30 hours or less, and even more preferably 24 hours or less.

[0032] Although there is no particular limitation on the amount of solution A relative to the support, the lower limit is preferably 0.9 times or more the pore volume of the support from the viewpoint of uniformly impregnating the support with element X. Furthermore, from the viewpoint of reducing the amount of solvent used, the upper limit is preferably 10 times or less the pore volume of the support, more preferably 5 times or less, and even more preferably 2 times or less.

[0033] Solid content A is obtained by impregnating the carrier with solution A. Solid content A is preferably obtained by removing the solvent. The solvent can be removed by a known method, such as a method using a rotary evaporator or a method of separating by filtration.

[0034] <Step (2)> In step (2), solid content A obtained in step (1) is heat-treated to obtain solid content B.

[0035] The heat treatment temperature is 150 to 300°C, with a lower limit of preferably 170°C or higher, more preferably 190°C or higher. It is believed that by performing the heat treatment at 150 to 300°C in step (2) and under the conditions of step (4-1) described below, an active site structure suitable for producing the target product is formed. The heating rate from when solid content A reaches 120°C until it reaches the heat treatment temperature is preferably 10°C / min or less, more preferably 5°C / min or less. Up to a temperature of 120°C, the solvent of solid content A is mainly removed, whereas at temperatures above 120°C, the active site structure of solid content A changes. It is believed that by setting the heating rate at 120°C or higher as the above condition, an active site structure more suitable for producing the target product is formed.

[0036] The heat treatment time is 15 minutes to 24 hours. The lower limit of the heat treatment time is preferably 30 minutes or more, more preferably 1 hour or more, even more preferably 5 hours or more, and particularly preferably 10 hours or more. The upper limit is preferably 20 hours or less, more preferably 15 hours or less.

[0037] <Step (3)> In step (3), a solution or dispersion (liquid B) containing one or more elements Y selected from alkali metal elements is impregnated into the solid content B obtained in step (2) to obtain a solid content C.

[0038] (Solution B) Solution B can be obtained by dissolving or dispersing a compound containing element Y in a solvent. The compound containing element Y may be dissolved or dispersed while stirring the solvent. Element Y preferably contains lithium, sodium, potassium, rubidium, or cesium, more preferably potassium, rubidium, or cesium, and even more preferably cesium. Element Y may contain one type or two or more types. The compound containing element Y is preferably a salt of element Y. The salt is not particularly limited, and examples include carbonates, nitrates, sulfates, acetates, ammonium salts, oxides, halides, and the like. These can be used alone or in combination. More specifically, when element Y is lithium, examples include lithium carbonate and lithium nitrate. When element Y is sodium, examples include sodium carbonate, sodium nitrate, and sodium sulfate. When element Y is potassium, examples include potassium carbonate, potassium nitrate, and potassium sulfate. When element Y is rubidium, examples include rubidium carbonate, rubidium nitrate, and rubidium sulfate. When the element Y is cesium, examples of the metal include cesium carbonate, cesium bicarbonate, cesium nitrate, and cesium sulfate.

[0039] From the viewpoint of improving the selectivity of the target product, the lower limit of the content of element Y in the obtained catalyst, relative to the mass of the entire catalyst, is preferably 3 mass% or more, more preferably 4 mass% or more, and even more preferably 6 mass% or more. The upper limit is preferably 25 mass% or less, more preferably 18 mass% or less, even more preferably 14 mass% or less, and particularly preferably 12 mass% or less. The content of element X can be adjusted by the amount of element X charged. Furthermore, when the number of moles of element X is MX and the number of moles of element Y is MY, from the viewpoint of improving the selectivity of the target product, the lower limit of the molar ratio MY / MX in the obtained catalyst is preferably 1.3 or more, more preferably 1.5 or more, even more preferably 1.7 or more, and particularly preferably 1.9 or more. The upper limit is preferably 8 or less, more preferably 6 or less, even more preferably 5.5 or less, and particularly preferably 5 or less. MY / MX can be adjusted by the amount of element Y charged relative to element X.

[0040] As the solvent, the same solvent as that used in the above-mentioned solution A can be used.

[0041] The amount of the compound containing element Y contained in Solution B is not particularly limited, but from the viewpoint of improving the selectivity of the target product, the lower limit is preferably 6 mmol or more, more preferably 14 mmol or more, and even more preferably 25 mmol or more, relative to 100 mL of solvent, and the upper limit is preferably 60 mmol or less, more preferably 50 mmol or less, and even more preferably 40 mmol or less, relative to 100 mL of solvent.

[0042] The obtained solution B is preferably allowed to stand before being impregnated into the solid content B. This reduces the average particle size of the compound containing the Y element in solution B, and in the obtained catalyst, the Y element is suitably highly dispersed, which tends to improve the selectivity for the target product. The lower limit of the time for which solution B is allowed to stand is preferably 15 minutes or more, and the upper limit is preferably 50 hours or less.

[0043] (Impregnation of solid content B with liquid B) There are no particular limitations on the method for impregnating solid content B with liquid B, and known methods can be used. Examples include a pore filling method in which liquid B is added to solid content B in an amount equal to the pore volume of solid content B, and an immersion method in which solid content B is immersed in liquid B. There are no particular limitations on the time for impregnating solid content B with liquid B, but from the viewpoint of successfully impregnating element Y into solid content B, the lower limit is preferably 15 minutes or more, and more preferably 1 hour or more. Furthermore, from the viewpoint of the time required for catalyst production, the upper limit is preferably 50 hours or less, more preferably 30 hours or less, and even more preferably 24 hours or less.

[0044] There is no particular limitation on the amount of solution B relative to solid content B, but from the viewpoint of uniformly impregnating element Y into solid content B, the lower limit is preferably 0.9 times or more the pore volume of solid content B. Furthermore, from the viewpoint of reducing the amount of solvent used, the upper limit is preferably 10 times or less the pore volume of solid content B, and more preferably 5 times or less.

[0045] Solid content C is obtained by impregnating solid content B with solution B. Solid content C is preferably obtained by removing the solvent. The solvent can be removed by a known method, such as a method using a rotary evaporator or a method of separating by filtration.

[0046] <Step (4-1)> In step (4-1), the solid content C obtained in step (3) is heat-treated at a heat treatment temperature of 100 to 300°C to obtain a catalyst. The heat treatment can remove the solvent remaining in the solid content C and unnecessary elements other than element X, element Y, and silica. In addition, by performing the heat treatment under such conditions, the peak height ratio I obtained by Raman spectroscopy can be reduced. ２ / I １ A catalyst can be obtained in which the value of (I) is within the specified range and the selectivity for the target product is high. The reason for this is thought to be that by performing heat treatment under specified conditions in step (2) and then further performing heat treatment in step (4-1), an active site structure suitable for producing the target product is formed in the resulting catalyst. In other words, the active sites for side reactions are reduced, and the active site components that cause the main reaction are suitably dispersed.

[0047] From the viewpoint of solvent removal, the lower limit of the heat treatment temperature is preferably 110°C or higher, and more preferably 120°C or higher. From the viewpoint of improving the selectivity of the target product, the upper limit is preferably 250°C or lower. The lower limit of the heat treatment time is preferably 15 minutes or higher, more preferably 30 minutes or higher, even more preferably 1 hour or higher, particularly preferably 5 hours or higher, and most preferably 10 hours or higher. The upper limit is preferably 24 hours or lower, more preferably 20 hours or lower, and even more preferably 15 hours or lower. In this manner, the catalyst can be produced.

[0048] [Catalyst Production Method 2] A second embodiment of the catalyst production method of the present invention includes the following steps: (1) a step of impregnating a silica-containing carrier with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain solid content A; (2) a step of heat-treating solid content A to obtain solid content B; (3) a step of impregnating solid content B with a solution or dispersion (liquid B) containing one or more elements Y selected from alkali metal elements to obtain solid content C; and (4-2) a step of heat-treating solid content C at a heat treatment temperature of 400 to 450°C to obtain a catalyst. In addition, in the second embodiment of the catalyst production method of the present invention, in step (4-2), the rate of temperature increase from when solid content C reaches 120°C to when it reaches the heat treatment temperature is 10°C / min or less. Each step will be described in detail below.

[0049] <Step (1)> Step (1) and its preferred embodiments are the same as those in the first embodiment.

[0050] <Step (2)> In step (2), solid content A obtained in step (1) is heat-treated to obtain solid content B. The heat treatment temperature is preferably 100 to 200°C. It is believed that by performing the heat treatment under the conditions of step (4-2) described below, a more suitable active site structure is formed for the production of the target product. The lower limit of the heat treatment temperature is more preferably 110°C or higher. The upper limit is more preferably 150°C or lower, and even more preferably 130°C or lower. The lower limit of the heat treatment time is preferably 15 minutes or longer, more preferably 1 hour or longer, even more preferably 5 hours or longer, and particularly preferably 10 hours or longer. The upper limit is preferably 24 hours or shorter, more preferably 20 hours or shorter, and even more preferably 15 hours or shorter.

[0051] <Step (3)> Step (3) and its preferred embodiments are the same as those in the first embodiment.

[0052] <Step (4-2)> In step (4-2), the solid content C obtained in step (3) is heat-treated at a heat treatment temperature of 400 to 450°C to obtain a catalyst. The heat treatment can remove the solvent remaining in the solid content C and unnecessary elements other than element X, element Y, and silica. In addition, by performing the heat treatment under such conditions, the peak height ratio I obtained by Raman spectroscopy can be reduced. ２ / I １ A catalyst having a high selectivity for the target product can be obtained, with the value of (I) being within the specified range. The reason for this is believed to be that the heat treatment in step (4-2) forms an active site structure suitable for producing the target product in the resulting catalyst. That is, the active sites for side reactions are reduced, and the active site components that cause the main reaction are suitably dispersed.

[0053] The heating rate from when the solid content C reaches 120°C until the heat treatment temperature is reached is 10°C / min or less. Up to 120°C, the solvent in the solid content C is mainly removed, whereas at temperatures above 120°C, the active site structure of the solid content C changes. It is believed that by setting the heating rate at 120°C or higher as the above condition, a more suitable active site structure is formed for the production of the target product. The lower limit of the heating rate from when the solid content C reaches 120°C until the heat treatment temperature is reached is preferably 2°C / min or more, and the upper limit is more preferably 8°C / min or less. From the viewpoint of reducing the active sites for side reactions in the solid content C, the lower limit of the heat treatment time is preferably 3 hours or more, more preferably 4 hours or more, and even more preferably 6 hours or more. Furthermore, the upper limit is preferably 24 hours or less, more preferably 20 hours or less, and even more preferably 15 hours or less. In this manner, the catalyst can be produced.

[0054] [Catalyst Production Method 3] A third embodiment of the catalyst production method of the present invention includes the following steps: (1) a step of impregnating a silica-containing carrier with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain solid content A; (2) a step of heat-treating solid content A to obtain solid content B; (3) a step of impregnating solid content B with a solution or dispersion (liquid B) containing one or more elements Y selected from alkali metal elements to obtain solid content C; and (4-3) a step of heat-treating solid content C at a heat treatment temperature of more than 450°C and not more than 700°C to obtain a catalyst. Furthermore, in the third embodiment of the catalyst production method of the present invention, in step (4-3), the rate of temperature increase from when solid content C reaches 120°C to when it reaches the heat treatment temperature is 10°C / min or less.

[0055] Each step will be described in detail below. <Step (1)> Step (1) and its preferred embodiment are the same as those in the first embodiment. <Step (2)> Step (2) and its preferred embodiment are the same as those in the second embodiment. <Step (3)> Step (3) and its preferred embodiment are the same as those in the first embodiment.

[0056] <Step (4-3)> In step (4-3), the solid content C obtained in step (3) is heat-treated at a heat treatment temperature of more than 450°C and not more than 700°C to obtain a catalyst. The heat treatment can remove the solvent remaining in the solid content C and unnecessary elements other than element X, element Y, and silica. In addition, by performing the heat treatment under such conditions, the peak height ratio I obtained by Raman spectroscopy can be reduced. ２ / I １ A catalyst having a high selectivity for the target product can be obtained, with the value of (I) being within the specified range. The reason for this is believed to be that the heat treatment in step (4-3) forms an active site structure suitable for producing the target product in the resulting catalyst. That is, the active sites for side reactions are reduced, and the active site components that cause the main reaction are suitably dispersed.

[0057] From the viewpoint of improving the selectivity of the target product, the lower limit of the heat treatment temperature is preferably 500°C or higher, more preferably 550°C or higher. The upper limit is preferably 650°C or lower, more preferably 600°C or lower. The temperature rise rate from when solid content C reaches 120°C to when it reaches the heat treatment temperature is 10°C / min or lower. Up to a temperature of 120°C, the solvent of solid content C is mainly removed, whereas at temperatures of 120°C or higher, the active site structure of solid content C changes. It is believed that by setting the temperature rise rate at 120°C or higher as the above condition, an active site structure more suitable for the production of the target product is formed. The lower limit of the temperature rise rate from when solid content C reaches 120°C to when it reaches the heat treatment temperature is more preferably 2°C / min or higher, and the upper limit is more preferably 8°C / min or lower.

[0058] The lower limit of the heat treatment time is preferably 15 minutes or more, more preferably 1 hour or more, even more preferably 3 hours or more, particularly preferably 10 hours or more, and most preferably 15 hours or more, from the viewpoint of reducing the active sites of side reactions in the solid content C. The upper limit is preferably 48 hours or less, and more preferably 24 hours or less.

[0059] In this manner, the catalyst can be produced.

[0060] [Method for Producing Unsaturated Carboxylic Acid and / or Unsaturated Carboxylic Acid Ester] By reacting a carboxylic acid and / or a carboxylic acid ester with formaldehyde in the presence of a catalyst according to one embodiment of the present invention or a catalyst produced by a production method according to one embodiment of the present invention, the corresponding unsaturated carboxylic acid and / or unsaturated carboxylic acid ester can be produced. That is, another embodiment of the present invention is a method for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester from a carboxylic acid and / or a carboxylic acid ester and formaldehyde using the catalyst. This allows the production of an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester with high selectivity.

[0061] The carboxylic acid and / or carboxylic acid ester is preferably a compound represented by the following formula (I): １ -CH ２ -COOR ２ Formula (I)

[0062] In the above formula (I), R １ and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. Methyl propionate is preferred as the compound represented by formula (I). The catalyst according to this embodiment is particularly effective in a method for producing methacrylic acid and / or methyl methacrylate from methyl propionate and formaldehyde.

[0063] The reaction of a carboxylic acid and / or a carboxylic acid ester with formaldehyde produces an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester by contacting a reaction raw material containing the carboxylic acid and / or the carboxylic acid ester and formaldehyde with a catalyst. In the reaction raw material, the molar ratio of formaldehyde to the total number of moles of the carboxylic acid and the carboxylic acid ester is not particularly limited, but from the viewpoint of improving the selectivity of the target product, it is preferably 0.05 to 20. Furthermore, it is more preferable that the lower limit is 0.2 or more and the upper limit is 15 or less.

[0064] From the viewpoint of improving the selectivity of the target product, the reaction is preferably carried out in the presence of an alcohol. When the reaction is carried out in the presence of an alcohol, the molar ratio of the alcohol to the total number of moles of carboxylic acid and / or carboxylic acid ester is not particularly limited, but is preferably 0.05 to 20. The lower limit is more preferably 0.1 or more and the upper limit is more preferably 10 or less.

[0065] The composition may contain compounds other than those mentioned above, such as water, within the scope of not significantly impairing the effects of the present invention.

[0066] The reaction temperature in the above reaction is not particularly limited, but from the viewpoint of improving the selectivity of the target product, the lower limit is preferably 100° C. or higher, more preferably 200° C. or higher, and even more preferably 250° C. or higher. The upper limit is preferably 400° C. or lower, more preferably 370° C. or lower, and even more preferably 360° C. or lower.

[0067] In the above reaction, the contact time between the reaction raw materials and the catalyst is not particularly limited, but from the viewpoint of improving the selectivity of the target product, the lower limit is preferably 0.1 seconds or more, more preferably 1 second or more, and even more preferably 2 seconds or more, and from the viewpoint of suppressing the progress of side reactions, it is preferably 100 seconds or less, more preferably 50 seconds or less, and even more preferably 30 seconds or less.

[0068] The carboxylic acid and / or carboxylic acid ester contained in the reaction raw material can be produced by a known method. When the carboxylic acid and / or carboxylic acid ester is methyl propionate, it can be produced by the carbonylation reaction of ethylene. The carbonylation reaction of ethylene is a method for producing methyl propionate by reacting ethylene with carbon monoxide in the presence of a catalyst that enables the carbonylation of ethylene. The carbonylation reaction of ethylene will be described in detail below.

[0069] The amount of ethylene relative to carbon monoxide is not particularly limited, but the lower limit is preferably 0.01 mole or more, more preferably 0.1 mole or more, relative to 100 moles of carbon monoxide, and the upper limit is preferably 100 moles or less, more preferably 10 moles or less.

[0070] The reaction temperature in the carbonylation reaction is not particularly limited, but the lower limit is preferably 20° C. or higher, more preferably 40° C. or higher, and even more preferably 70° C. or higher. The upper limit is preferably 250° C. or lower, more preferably 150° C. or lower, and even more preferably 120° C. or lower. The reaction time is not particularly limited, but is preferably 0.1 to 100 hours.

[0071] The catalyst that enables the carbonylation of ethylene is not particularly limited, and known catalysts can be used. Examples of such catalysts include palladium catalysts having a phosphine-based ligand. Specific examples of such palladium catalysts include those described in JP-A-10-511034. Furthermore, such palladium catalysts can be produced by known methods.

[0072] The carbonylation reaction is preferably carried out in the presence of an alcohol. The alcohol is not particularly limited, and examples thereof include methanol, ethanol, propanol, 2-propanol, 2-butanol, and t-butyl alcohol. Of these, methanol or ethanol is preferred. The alcohol may be used alone or in combination of two or more.

[0073] The amount of ethylene relative to the alcohol is not particularly limited, but the lower limit is preferably 0.01 mole or more, more preferably 0.1 mole or more, relative to 100 moles of alcohol, and the upper limit is preferably 100 moles or less, more preferably 10 moles or less.

[0074] In the carbonylation reaction, carbon monoxide may be supplied in combination with an inert gas, such as hydrogen, nitrogen, carbon dioxide, or argon.

[0075] Although unsaturated carboxylic acids and / or unsaturated carboxylic acid esters can be produced by the above-mentioned methods, the produced unsaturated carboxylic acids and / or unsaturated carboxylic acid esters usually contain impurities. Therefore, in order to remove the impurities, it is preferable to purify the obtained unsaturated carboxylic acids and / or unsaturated carboxylic acid esters by a known method such as distillation. The purification conditions may be appropriately adjusted so as to obtain unsaturated carboxylic acids and / or unsaturated carboxylic acid esters of the desired purity.

[0076] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0077] (Heat Treatment) In this example, the heat treatment of solid content A and solid content C was carried out using a muffle furnace. The muffle furnace used was product number FUM142PA (manufactured by Advantec Co., Ltd.) or product number DF62 (manufactured by Yamato Scientific Co., Ltd.).

[0078] (Raman Spectroscopic Measurement) The Raman spectroscopic measurement of the catalyst was carried out using a 3D microscopic laser Raman spectrometer Nanofinder (manufactured by Tokyo Instruments Inc.) at an excitation wavelength of 488 nm. ２ / I １ was measured by the following procedure. Raman spectroscopy was performed at five points on the cross section of the catalyst divided into two, changing the measurement location at regular intervals from one end to the other. －１ Minimum strength at 867±2cm －１ The baseline was corrected by connecting the minimum intensities at 417 ± 10 cm. －１ The length of the perpendicular line from the peak top to the baseline at １ Also, 1050±10cm －１ The length of the perpendicular line from the peak top to the line drawn between both ends of the peak is I ２ In addition, 1050±10cm －１ If there is no peak near I ２was set to 0. The above procedure was carried out for the five points analyzed, and the arithmetic mean value I １ , I ２ and I ２ / I １ was calculated.

[0079] (X-ray fluorescence analysis) The contents of element X and element Y were measured by X-ray fluorescence analysis. In addition, the molar ratio of element X to element Y, MY / MX, was calculated from the obtained contents of element X and element Y. X-ray fluorescence analysis was performed using a ZSX Primus IV (manufactured by Rigaku Corporation) under a helium atmosphere.

[0080] (Measurement of BET Specific Surface Area) The BET specific surface area of ​​the catalyst was calculated by the BET single-point method using a nitrogen adsorption measuring device Macsorb (manufactured by Mountech Co., Ltd.).

[0081] (Reaction Evaluation) The reaction evaluation of the catalyst was carried out using as an example a reaction for producing methacrylic acid and / or methyl methacrylate from methyl propionate and formaldehyde. The reaction raw materials and reaction products in the reaction evaluation were analyzed using gas chromatography (Shimadzu Corporation, GC-2010). From the analysis results, the selectivity of methacrylic acid and methyl methacrylate was calculated using the following formula (II): Selectivity of methacrylic acid and methyl methacrylate (%) = (number of moles of methacrylic acid and methyl methacrylate produced) / (number of moles of methyl propionate reacted) × 100 ... formula (II)

[0082] Example 1 4.5 g of zirconium oxynitrate dihydrate (Kishida Chemical, special grade) was dissolved in 135 mL of methanol (Nacalai Tesque, special grade) and allowed to stand for 24 hours to prepare Solution A. 60 g of CARiACT Q-15 (Fuji Silysia Chemical Ltd., particle size 1.7-4 mm, average pore size 10 nm) was used as a carrier, and the solution was immersed in Solution A and allowed to stand for 3.5 hours. The solvent was then removed using a rotary evaporator to obtain Solid Content A. The obtained Solid Content A was heat-treated at a heat treatment temperature of 120°C for 14 hours to obtain Solid Content B. The temperature rise rate of Solid Content A was 0.17°C / min. 30 g of the obtained Solid Content B was immersed for 3.5 hours in Solution B, which was prepared by dissolving 4.9 g of cesium carbonate (Wako Pure Chemical Industries, first grade) in 65 mL of methanol. The solution was then removed by filtration to obtain Solid Content C. The obtained solid component C was heat-treated at a heat treatment temperature of 500°C for 3 hours to obtain a catalyst. The temperature increase rate of solid component C was 5°C / min. The results of Raman spectroscopy, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1.

[0083] Next, reaction evaluation was performed according to the following procedure. Approximately 3 g of the obtained catalyst was loaded into a reactor. Next, under atmospheric pressure, a reaction raw material liquid having a molar ratio of methyl propionate, methanol, formaldehyde, and water of 1:1.40:0.19:0.5 was passed through an evaporator at 300 ° C. at a flow rate of 0.160 mL / min and passed through a reactor at 330 ° C. for 16 hours. Next, under atmospheric pressure, a reaction raw material liquid having a molar ratio of methyl propionate, methanol, formaldehyde, and water of 1:0.64:0.27:0.01 was passed through an evaporator at 300 ° C. and supplied to a reactor at 330 ° C. to produce methacrylic acid and methyl methacrylate. The vapor at the reactor outlet was cooled and condensed to recover the reaction product. The analysis results of the obtained reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy was ２ / I １ The relationship between the selectivity for methacrylic acid and methyl methacrylate and the reaction temperature is shown in FIG.

[0084] <Examples 2 to 8> Solid content C was obtained in the same manner as in Example 1. The obtained solid content C was heat-treated in the same manner as in Example 1, except that the heat treatment temperature and heat treatment time were changed as shown in Table 1, to obtain a catalyst. The results of Raman spectroscopy, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1. Next, reaction evaluation was carried out in the same manner as in Example 1. The analysis results of the reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy was ２ / I １ The relationship between the selectivity for methacrylic acid and methyl methacrylate and the reaction temperature is shown in FIG.

[0085] Example 9 Solid content A was obtained in the same manner as in Example 1. The obtained solid content A was heat-treated in the same manner as in Example 1, except that the heat treatment temperature and heat treatment time were changed as shown in Table 1, to obtain solid content B. Solid content C was obtained using the obtained solid content B in the same manner as in Example 1. The obtained solid content C was heat-treated at a heat treatment temperature of 120°C for 14 hours to obtain a catalyst. At this time, the temperature rise rate of solid content C was 0.17°C / min. The results of Raman spectroscopy measurement, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1. Next, reaction evaluation was performed in the same manner as in Example 1. The analysis results of the reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy measurement ２ / I １ The relationship between the selectivity for methacrylic acid and methyl methacrylate and the reaction temperature is shown in FIG.

[0086] Examples 10 and 11 Solid content A was obtained in the same manner as in Example 1. The obtained solid content A was heat-treated in the same manner as in Example 1, except that the heat treatment temperature and heat treatment time were changed as shown in Table 1, to obtain solid content B. Solid content C was obtained using the obtained solid content B in the same manner as in Example 1. The obtained solid content C was heat-treated in the same manner as in Example 9 to obtain a catalyst. The results of Raman spectroscopy measurement, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1. Next, reaction evaluation was performed in the same manner as in Example 1. The analysis results of the reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy measurement was ２ / I １ The relationship between the selectivity for methacrylic acid and methyl methacrylate and the reaction temperature is shown in FIG.

[0087] Example 12 Solid content A was obtained in the same manner as in Example 1. The obtained solid content A was heat-treated at a heat treatment temperature of 200°C for 14 hours to obtain solid content B. At this time, the temperature increase rate of solid content A was 5°C / min. Using the obtained solid content B, solid content C was obtained in the same manner as in Example 1. The obtained solid content C was heat-treated in the same manner as in Example 9 to obtain a catalyst. The results of Raman spectroscopy measurement, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1. Next, reaction evaluation was performed in the same manner as in Example 1. The analysis results of the reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy measurement was ２ / I １ The relationship between the selectivity for methacrylic acid and methyl methacrylate and the reaction temperature is shown in FIG.

[0088] Example 13 Solid content C was obtained in the same manner as in Example 1. The obtained solid content C was heat-treated in the same manner as in Example 1, except that the heat treatment temperature and heat treatment time were changed as shown in Table 1, to obtain a catalyst. The results of Raman spectroscopy, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1. Next, reaction evaluation was performed in the same manner as in Example 1. The analysis results of the reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy was ２ / I １ The relationship between the selectivity for methacrylic acid and methyl methacrylate and the reaction temperature is shown in FIG.

[0089] Comparative Example 1 Solid content C was obtained in the same manner as in Example 1. The obtained solid content C was heat-treated in the same manner as in Example 9 to obtain a catalyst. The results of Raman spectroscopy, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1. Next, reaction evaluation was performed in the same manner as in Example 1. The analysis results of the reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy ２ / I １The relationship between the selectivity of methacrylic acid and methyl methacrylate and the selectivity of methacrylic acid and methyl methacrylate is shown in Figure 1. <Comparative Example 2> Solid content C was obtained in the same manner as in Example 1. The obtained solid content C was heat treated in the same manner as in Example 1, except that the heat treatment temperature and heat treatment time were changed as shown in Table 1, to obtain a catalyst. The results of Raman spectroscopy measurement, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1. Next, reaction evaluation was performed in the same manner as in Example 1. The analysis results of the reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy measurement ２ / I １ The relationship between the selectivity for methacrylic acid and methyl methacrylate and the reaction temperature is shown in FIG.

[0090] Comparative Example 3 Solid content C was obtained in the same manner as in Example 1. The obtained solid content C was heat-treated at a heat treatment temperature of 450°C for 3 hours to obtain a catalyst. At this time, the temperature rise rate of solid content C was 25°C / min. The results of Raman spectroscopy measurement, X-ray fluorescence analysis, and BET specific surface area measurement of the catalyst are shown in Table 1. Next, reaction evaluation was performed in the same manner as in Example 1. The analysis results of the reaction product are shown in Table 1. In addition, the peak height ratio I obtained by Raman spectroscopy measurement ２ / I １ The relationship between the selectivity for methacrylic acid and methyl methacrylate and the reaction temperature is shown in FIG.

[0091]

[0092] As shown in Table 1 and Figure 1, the peak height ratio I ２ / I １ In Examples 1 to 13, which used catalysts in which the value of I was within the specified range, ２ / I １ It can be seen that the selectivity to methacrylic acid and methyl methacrylate is significantly improved compared to Comparative Examples 1 to 3, in which a catalyst in which the heat treatment conditions for solid content A and solid content C are within the specified ranges was used. It can also be seen that the selectivity to methacrylic acid and methyl methacrylate is significantly improved in Examples 1 to 13, in which a catalyst in which the heat treatment conditions for solid content A and solid content C are within the specified ranges was used, in which the selectivity to methacrylic acid and methyl methacrylate is significantly improved compared to Comparative Examples 1 to 3, in which a catalyst in which the heat treatment conditions for solid content A and solid content C are outside the specified ranges was used.

Claims

1. A catalyst comprising one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium, one or more elements Y selected from alkali metal elements, and silica, 417±10 cm obtained by Raman spectroscopy －１ The maximum peak height at I １ , 1050±10cm －１ The maximum peak height at I ２ When the peak height ratio I ２ / I １ A catalyst in which the ratio is 0 to 1.

2.

2. I ２ / I １ The catalyst according to claim 1, wherein is 0 to 0.

5.

3. The catalyst according to claim 1, which is a catalyst for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester.

4. 2. The catalyst of claim 1, wherein the element X comprises zirconium.

5. The catalyst according to claim 1, wherein the content of the element X is 0.3 to 10 mass % based on the mass of the entire catalyst.

6. The catalyst of claim 1 , wherein the element Y comprises cesium.

7. The catalyst according to claim 1, wherein the content of the element Y is 3 to 25 mass % based on the mass of the entire catalyst.

8. 2. The catalyst according to claim 1, wherein the molar ratio MY / MX is 1.3 to 8, where MX is the number of moles of the element X and MY is the number of moles of the element Y.

9. BET specific surface area is 50 to 600 m ２ The catalyst according to claim 1, wherein the molar ratio is 1:

1.

10. Using the catalyst according to any one of claims 1 to 9, a carboxylic acid and / or a carboxylic acid A method for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester, comprising producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester from an ester and formaldehyde.

11. (1) A step of impregnating a support containing silica with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain a solid content A; (2) heat-treating the solid content A to obtain a solid content B; (3) A step of impregnating the solid component B with a solution or dispersion liquid (liquid B) containing one or more elements Y selected from alkali metal elements to obtain a solid component C; (4-1) A step of heat-treating the solid content C at a heat treatment temperature of 100 to 300° C. to obtain a catalyst; A method for producing a catalyst comprising the steps of: In the step (2), the solid content A is heat-treated at a heat treatment temperature of 150 to 300° C. for 15 minutes to 24 hours.

12. The method for producing a catalyst according to claim 11, wherein in the step (2), a heating rate from when the solid content A reaches 120° C. to when the solid content A reaches the heat treatment temperature is 10° C. / min or less.

13. The method for producing a catalyst according to claim 11, wherein in the step (4-1), the solid content C is heat-treated for 15 minutes to 24 hours.

14. (1) A step of impregnating a support containing silica with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain a solid content A; (2) heat-treating the solid content A to obtain a solid content B; (3) A step of impregnating the solid content B with a solution or dispersion liquid (liquid B) containing one or more elements Y selected from alkali metal elements to obtain a solid content C; (4-2) heat-treating the solid content C at a heat treatment temperature of 400 to 450° C. to obtain a catalyst; A method for producing a catalyst comprising the steps of: In the step (4-2), a heating rate from when the solid content C reaches 120° C. to when the solid content C reaches the heat treatment temperature is 10° C. / min or less.

15. The method for producing a catalyst according to claim 14, wherein in the step (4-2), the solid content C is heat-treated for 3 to 24 hours.

16. The method for producing a catalyst according to claim 14, wherein in the step (4-2), a heating rate from when the solid content C reaches 120° C. to when the solid content C reaches the heat treatment temperature is 2 to 8° C. / min.

17. (1) A step of impregnating a support containing silica with a solution or dispersion (liquid A) containing one or more elements X selected from the group consisting of boron, magnesium, aluminum, zirconium, hafnium, and titanium to obtain a solid content A; (2) heat-treating the solid content A to obtain a solid content B; (3) A step of impregnating the solid content B with a solution or dispersion liquid (liquid B) containing one or more elements Y selected from alkali metal elements to obtain a solid content C; (4-3) heat-treating the solid component C at a heat treatment temperature of more than 450° C. and not more than 700° C. to obtain a catalyst; A method for producing a catalyst comprising the steps of: In the step (4-3), a heating rate from when the solid content C reaches 120° C. to when the solid content C reaches the heat treatment temperature is 10° C. / min or less.

18. The method for producing a catalyst according to claim 17, wherein in the step (4-3), the solid content C is heat-treated for 15 minutes to 24 hours.

19. The method for producing a catalyst according to claim 17, wherein in the step (4-3), a heating rate from when the solid content C reaches 120° C. to when the solid content C reaches the heat treatment temperature is 2 to 8° C. / min.

20. The method for producing a catalyst according to any one of claims 14 to 19, wherein in the step (2), the solid content A is heat-treated at a heat treatment temperature of 100 to 200°C.

21. The method for producing a catalyst according to any one of claims 14 to 19, wherein in the step (2), the solid content A is heat-treated for 15 minutes to 24 hours.

22. The method for producing a catalyst according to any one of claims 11 to 19, wherein the catalyst is a catalyst for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester.

23. The method for producing a catalyst according to any one of claims 11 to 19, wherein in the step (1), the element X includes zirconium.

24. The method for producing a catalyst according to any one of claims 11 to 19, wherein in the step (3), the element Y includes cesium.

25. A method for producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester, comprising producing an unsaturated carboxylic acid and / or an unsaturated carboxylic acid ester from a carboxylic acid and / or a carboxylic acid ester and formaldehyde using a catalyst produced by the method for producing a catalyst according to any one of claims 11 to 19.