JP2006075819A - Catalyst for producing alpha, beta-unsaturated carboxylic acid and method for preparation thereof and method for producing alpha, beta-unsaturated carboxylic acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst for producing an α,β-unsaturated carboxylic acid from an olefin or an α,β-unsaturated aldehyde through the liquid phase oxidation in good reaction performance, a method for preparing this catalyst and a method for producing the α,β-unsaturated carboxylic acid by using this catalyst. <P>SOLUTION: This catalyst for producing the α,β-unsaturated carboxylic acid comprises a carrier having 0.40-1.50 cc/g total pore volume as measured by the nitrogen gas adsorption method and a metal carried on the carrier. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a catalyst for producing an α, β-unsaturated carboxylic acid from an olefin or an α, β-unsaturated aldehyde by liquid phase oxidation, a method for producing the same, and an α, β-unsaturated carboxylic acid using the catalyst. The present invention relates to a method for producing an acid.

  Many α, β-unsaturated carboxylic acids are industrially useful. Acrylic acid and methacrylic acid are used in extremely large quantities for applications such as synthetic resin raw materials. For example, in the production of methacrylic acid, there are a gas phase oxidation method, a liquid phase oxidation method of isobutene, a method via acetone cyanohydrin, etc., but there are no particularly advantageous methods. It is produced industrially.

  A catalyst and a method for obtaining an α, β-unsaturated carboxylic acid by liquid phase oxidation of an olefin or α, β-unsaturated aldehyde with molecular oxygen have been actively studied. For example, a method of performing in the presence of a catalyst supporting gold (Patent Document 1), a method of using a palladium metal catalyst (Patent Documents 2 to 6), a method of using a molybdenum compound and a palladium catalyst (Patent Document 7), and the like. .

Some of the catalysts described in Patent Documents 1 to 7 are supported on a support such as activated carbon, alumina, or silica. Regarding the physical properties of these carriers, there is only a description in Patent Document 1 that “hydrophobic carriers or those obtained by subjecting ordinary carriers to hydrophobic treatment are good”. I can't.
JP 2001-172222 A JP 60-155148 A JP 60-139341 A JP-A-60-139634 U.S. Pat. No. 4,435,598 International Publication No. 02/083299 Pamphlet JP 56-59722 A

  When this inventor manufactured acrylic acid from propylene using the catalyst manufactured according to the method described in the Example of patent documents 1-7, the by-product described in patent documents 1-7 (for example, In addition to acetaldehyde, acetone, acrolein, acetic acid, carbon dioxide), various polymers and oligomers were found to be a by-product. In Patent Documents 1 to 7, these polymers and oligomers are not captured, and reaction results such as the selectivity and productivity of actual acrylic acid including these by-products are in the Examples of Patent Documents 1 to 7. It was found to be lower than that described. Thus, the reaction results in the method for producing an α, β-unsaturated carboxylic acid have not been sufficient yet, and further improvement has been desired.

  The present invention relates to a catalyst capable of producing an α, β-unsaturated carboxylic acid with good reaction results by liquid phase oxidation from an olefin or an α, β-unsaturated aldehyde, a production method thereof, and α, β using the catalyst. -It aims at providing the manufacturing method of unsaturated carboxylic acid.

  The present inventors have found that the catalyst performance is greatly influenced by the physical properties of the carrier used when producing the catalyst, particularly the pore volume, and have led to the present invention.

  The catalyst for producing an α, β-unsaturated carboxylic acid according to the present invention is a catalyst for producing an α, β-unsaturated carboxylic acid from an olefin or an α, β-unsaturated aldehyde by liquid phase oxidation, which is a nitrogen gas. A catalyst for producing an α, β-unsaturated carboxylic acid, characterized in that a metal is supported on a support having a total pore volume measured by an adsorption method of 0.40 to 1.50 cc / g.

  The method for producing a catalyst for producing an α, β-unsaturated carboxylic acid according to the present invention is a method for producing the catalyst for producing an α, β-unsaturated carboxylic acid as described above, wherein the metal compound is reduced in the presence of the carrier. It is a manufacturing method of the catalyst for (alpha), (beta) -unsaturated carboxylic acid manufacturing reduced by.

  The method for producing an α, β-unsaturated carboxylic acid according to the present invention is a method in which an olefin or an α, β-unsaturated aldehyde is dissolved in a liquid phase with molecular oxygen in the presence of the above-mentioned catalyst for producing an α, β-unsaturated carboxylic acid. This is a method for producing an α, β-unsaturated carboxylic acid that is oxidized at the same time.

  According to the present invention, a catalyst capable of producing an α, β-unsaturated carboxylic acid with good reaction results by liquid phase oxidation from an olefin or an α, β-unsaturated aldehyde, its production method, and α using the catalyst , Β-unsaturated carboxylic acid production method can be provided.

(1) Catalyst for producing α, β-unsaturated carboxylic acid The catalyst for producing α, β-unsaturated carboxylic acid of the present invention (hereinafter sometimes simply referred to as “catalyst”) is olefin or α, β-unsaturated. A catalyst for producing an α, β-unsaturated carboxylic acid from a saturated aldehyde by liquid phase oxidation, wherein the total pore volume measured by a nitrogen gas adsorption method is 0.40 to 1.50 cc / g. A catalyst for producing an α, β-unsaturated carboxylic acid characterized in that a metal is supported.

  By using the catalyst as described above, it is possible to produce an α, β-unsaturated carboxylic acid with good reaction results by liquid phase oxidation from an olefin or an α, β-unsaturated aldehyde. The catalyst of the present invention is effective for liquid phase oxidation of acrolein and methacrolein, particularly among propylene, isobutylene and α, β-unsaturated aldehyde among olefins.

  The catalyst of the present invention is a supported catalyst in which a metal is supported on a carrier. Hereinafter, the support | carrier and metal which can be used as a catalyst of this invention are demonstrated.

(1-1) Carrier There are no particular restrictions on the type of carrier, and typical carriers such as activated carbon, carbon black, silica, alumina, magnesia, calcia, zirconia, and titania can be used. Among them, it is preferable to use activated carbon or silica. Normally, activated carbon is produced by a process of carbonization, sizing, activation, washing, drying and pulverization, but the production process is not particularly limited in the present invention. There is no restriction | limiting in particular also in the carbonaceous substance which is a raw material of activated carbon, Various raw materials, such as coconut husk, coal, woody, and a synthetic resin, can be used. There is no restriction | limiting in particular also in the activation method, It can activate using water vapor | steam, a carbon dioxide gas, oxygen, phosphoric acid, a phosphate, zinc chloride, etc. Activated activated carbon is washed with mineral acid, hydrochloric acid, water, etc., if necessary, dried, and then used. Of the impurities contained in the product activated carbon, chlorine is likely to adversely affect the catalyst performance, so it is preferable that it be as small as possible. Therefore, it is preferable that the activated carbon produced using zinc chloride or hydrochloric acid is sufficiently washed to remove contained chlorine as much as possible. There is no restriction | limiting in particular also in the shape of activated carbon, Various activated carbons, such as a powder form, spherical shape, a pellet form, and a fiber form, can be used. BET specific surface area of the activated carbon is preferably at least 300 meters ² / g, and particularly preferably equal to or greater than 600m ² / g. Moreover, 4000 m < ² > / g or less is preferable and 2500 m < ² > / g or less is especially preferable.

  In the present invention, a carrier having a total pore volume measured by a nitrogen gas adsorption method of 0.40 to 1.50 cc / g is selected and used. By using such a carrier, α, β-unsaturated carboxylic acid can be produced from olefin or α, β-unsaturated aldehyde by liquid phase oxidation with high selectivity and high productivity. Hereinafter, the configuration and the manufacturing method will be described.

In particular, in order to obtain the target product with high selectivity, it is preferable to select a carrier having a total pore volume of 0.40 to 0.80 cc / g. More preferably, it is 0.47 cc / g or more, More preferably, it is 0.70 cc / g or less, More preferably, it is 0.67 cc / g or less. By using a carrier that satisfies such conditions, there is little production of by-products, and target products such as acrylic acid and methacrylic acid can be obtained with good selectivity. This is considered to be because the by-products such as oligomers are suppressed and the selectivity of the target product is further improved by setting the total pore volume to a smaller range in the above range. In this case, the ratio of the pore volume of the mesopores having a pore diameter of 2 nm to 50 nm is preferably 40% or less, more preferably 35% or less, and further preferably 30% or less of the total pore volume. Particularly preferably, it is 20% or less. Further, the ratio of the pore volume of the mesopores is preferably 5% or more of the total pore volume, more preferably 7% or more, and further preferably 9% or more. In particular, in this case, if the pore volume is the same, the lower the ratio of mesopores, the more difficult it is to produce by-products such as oligomers. Further, BET specific surface area of the carrier is preferably at least 600 meters ² / g, more preferably at least 800 m ² / g, preferably not more than 2000 m ² / g, more preferably at most 1500 m ² / g.

In particular, in order to obtain the target product with high productivity, it is preferable to select a carrier having a total pore volume of 0.80 to 1.50 cc / g. More preferably, it is 0.85 cc / g or more, More preferably, it is 0.90 cc / g or more, More preferably, it is 1.40 cc / g or less, More preferably, it is 1.30 cc / g or less. By using a carrier satisfying such conditions, the catalytic activity is high, and target products such as acrylic acid and methacrylic acid can be obtained with good productivity. This is considered to be that by making the pore volume a larger range in the above-mentioned range, the diffusion of reactants and products into the pores is facilitated, and the productivity is further improved. Further, the ratio of the pore volume of mesopores having a pore diameter of 2 nm or more and 50 nm or less is preferably 10% or more of the total pore volume, more preferably 20% or more, still more preferably 30% or more, particularly preferably. Is 40% or more. Moreover, it is preferably 65% or less, more preferably 60% or less, and further preferably 55% or less. In particular, in this case, if the pore volume is the same, the higher the ratio of mesopores, the easier the diffusion in the pores, and thus the production efficiency seems to be further improved. Further, BET specific surface area of the carrier is preferably at least 100 m ² / g, more preferably at least 300 meters ² / g, preferably not more than 5000 m ² / g, more preferably at most 4000 m ² / g.

  The total pore volume of the carrier, the pore volume of the mesopores having a pore diameter of 2 nm to 50 nm and the BET specific surface area are measured by, for example, an automatic specific surface area / pore distribution measuring device TriStar 3000 (trade name) manufactured by Micromeritics. it can.

(1-2) Metal The metal supported on the carrier is not particularly limited as long as it functions as a catalyst for liquid phase oxidation, but is preferably a noble metal, more preferably palladium or gold, and particularly preferably palladium. One kind or two or more kinds of metals may be used. Moreover, the metal which does not function as a catalyst of liquid phase oxidation may be included. From the viewpoint of catalytic activity, the amount of metal that does not function as a catalyst for liquid phase oxidation is preferably 50 atomic% or less.

  Here, in the present invention, it is preferable that palladium having an average particle diameter in the range of 1 to 8 nm is supported on the carrier. By selecting palladium as the metal and setting the average particle size within the above range, a catalyst capable of producing an α, β-unsaturated carboxylic acid from an α, β-unsaturated aldehyde in a higher yield can be obtained. The average particle diameter is more preferably 1.2 nm or more, and further preferably 1.4 nm or more. The average particle diameter is more preferably 7 nm or less, and further preferably 6 nm or less. At this time, a metal other than palladium in the catalyst may be contained, but from the viewpoint of catalytic activity, the metal other than palladium is preferably 50 atom% or less.

  Here, the average particle diameter of the palladium is a value obtained by measuring the palladium in the catalyst with a transmission electron microscope, and is specifically a value calculated as follows.

  The observation image of the transmission electron microscope is printed at an equal magnification, and 50 particles of palladium in the field of view are randomly picked up and each particle size is measured. Since the shape of the palladium region is almost circular, it is measured by approximating that it is all circular. This operation is carried out for three visual fields, and the average of the measured values is taken as the average particle diameter. The observation with a transmission electron microscope is performed at an observation magnification capable of measuring the particle diameter of palladium.

  The average particle diameter of palladium in the catalyst is the type of support used and the BET specific surface area, the type of solvent used for the preparation of the catalyst and the mixing ratio in the case of a mixed solvent, the type and concentration of the palladium compound that is the raw material of the catalyst, It varies depending on various conditions such as temperature and time for reducing the palladium compound. In the present invention, it is necessary to appropriately select and set those conditions, and to set the average particle diameter of palladium in the obtained catalyst within the above range.

(2) Method for Producing α, β-Unsaturated Carboxylic Acid Production Catalyst Next, a method for producing the above-described catalyst for producing an α, β-unsaturated carboxylic acid according to the present invention will be described.

  The method for producing the catalyst of the present invention is not particularly limited, but it is preferable to take a method of reducing a metal compound with a reducing agent in the presence of a carrier. Specifically, for example, a liquid phase reduction method in which a solution of a metal compound in which a carrier is dispersed is prepared, and a reducing agent is added thereto to reduce the solution, and a carrier impregnated with a metal compound solution is dried and reduced. It can be produced by a gas phase reduction method that reduces in an atmosphere. Of these, the liquid phase reduction method is preferred. Hereinafter, a method for producing a catalyst by the liquid phase reduction method will be described.

  The metal compound used is preferably a metal chloride, oxide, acetate, nitrate, sulfate, tetraammine complex, acetylacetonate complex or the like, which is a metal chloride, oxide, acetate. Nitrate, sulfate, or sulfate is more preferable, and metal chloride, acetate, or nitrate is more preferable. These can be used alone or in combination.

  Moreover, as these metal compounds, it is also preferable to use those which do not substantially contain chlorine as an impurity. More specifically, the chlorine in the metal compound is preferably 1000 ppm or less. That is, it is preferable to use a metal compound that does not contain chlorine, such as acetate, nitrate, and bisacetylacetonate complex. When palladium is selected as the metal, for example, palladium acetate, palladium nitrate, and bisacetylacetonate palladium can be suitably used.

The solvent for dissolving the metal compound is appropriately selected depending on the solubility of the metal compound and the reducing agent and the dispersibility of the carrier, and is selected from water, alcohols, ketones, organic acids, hydrocarbons, or a group thereof. Two or more mixed solvents can be used. As the solvent, one or more organic solvents selected from the group consisting of alcohols, ketones, and organic acids are preferable. C ₂ -C ₆ organic acids, tertiary butanol, and C ₃ -C ₆ One kind selected from the group consisting of these ketones or a mixture thereof is more preferred.

  Since a catalyst with higher performance can be produced, it is also preferable to use a mixed solvent of an organic solvent and water. When a mixed solvent of an organic solvent and water is used, a mixed solvent of one or more organic solvents selected from the group consisting of alcohols, ketones and organic acids and water is preferable. Among these, a mixed solvent of one or two or more solvents selected from organic acids and water is preferable. The organic acids are preferably at least one selected from the group consisting of acetic acid, propionic acid, n-butyric acid, iso-butyric acid, n-valeric acid and iso-valeric acid. Of these, n-valeric acid or acetic acid is particularly preferred. The amount of water at that time is not particularly limited, but is preferably 5% by mass or more, more preferably 8% by mass or more, based on the mass of the mixed solvent. The amount of water is preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably 40% by mass or less. In the case of a mixed solvent, a uniform state is desirable, but a non-uniform state may be used.

  A carrier and a metal compound are added to the solvent in the solvent in the desired order or simultaneously to prepare a solution of the metal compound in which the carrier is dispersed. The concentration of the metal compound is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and particularly preferably 0.5% by mass or more. The concentration of the metal compound is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 7% by mass or less, and particularly preferably 4% by mass or less.

  Subsequently, a reducing agent is added to the metal compound solution in which the carrier is dispersed to reduce the metal compound solution, thereby obtaining a catalyst in which the metal is supported on the carrier.

  The reducing agent to be used is not particularly limited as long as it has an ability to reduce an oxidized metal in the metal compound. For example, hydrazine, formaldehyde, sodium borohydride, hydrogen, formic acid, formic acid salts, alcohols and olefins can be used. Among these, at least one selected from the group consisting of formaldehyde, propylene, isobutylene, 1-butene, and 2-butene is preferable, and formaldehyde, propylene, or isobutylene is more preferable.

  When a gas such as propylene is used as the reducing agent, it is preferable to carry out the reduction by charging a metal compound solution in which the carrier is dispersed in a pressurizing apparatus such as an autoclave and pressurizing the inside with a reducing agent. The pressure is preferably 0.1 to 1.0 MPa (gauge pressure; hereinafter, all pressures are expressed as gauge pressures).

  When the reducing agent is liquid or solid, the reduction can be performed by adding the reducing agent to the metal compound solution in which the carrier is dispersed. In this case, the amount of the reducing agent used is preferably about 1 to 50 mol with respect to 1 mol of the metal compound.

  The temperature and reduction time of the system at the time of reduction vary depending on the reduction method, the carrier and metal compound used, the solvent, the reducing agent, etc., but cannot generally be said, but in the case of the liquid phase reduction method, the reduction temperature is preferably −5 ° C. or higher. More preferably, it is 0 degreeC or more, More preferably, it is 15 degreeC or more. The reduction temperature is preferably 150 ° C. or lower, more preferably 100 ° C. or lower, and further preferably 80 ° C. or lower. The reduction time is preferably 0.1 hour or longer, more preferably 0.25 hour or longer, and further preferably 0.5 hour or longer. The reduction time is preferably 24 hours or less, more preferably 4 hours or less, still more preferably 3 hours or less, and particularly preferably 2 hours or less.

  After the reduction, the catalyst having the metal supported on the carrier is separated from the dispersion. Although this method is not specifically limited, For example, methods, such as filtration and centrifugation, can be used. The separated catalyst is appropriately dried. The drying method is not particularly limited, and various methods can be used.

  The concentration of the metal contained in the solution separated from the catalyst after the reduction is preferably 10 mg / l or less. This amount can be adjusted by the concentration of the metal compound before the reduction, the reduction conditions, and the like. The presence or absence of metal in the solution can be easily confirmed by adding a reducing agent such as hydrazine, and the amount of metal in the solution can be quantified by elemental analysis such as ICP.

  The metal loading ratio of the catalyst is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and particularly preferably 4% by mass with respect to the carrier before loading. % Or more. Further, the metal loading of the catalyst is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, and particularly preferably 15% by mass with respect to the mass of the carrier before loading. % Or less. The loading rate can be determined from the mass of the carrier used for preparing the catalyst, the mass of the metal in the metal compound, and the mass of the metal contained in the solution separated from the catalyst after the reduction.

  The catalyst thus produced may be used for the reaction in the form of a dispersion after washing with a solvent, or may be used for the reaction after separation by centrifugation or filtration.

  The catalyst may be activated before being subjected to liquid phase oxidation. The activation method is not particularly limited, and various methods can be used. As a method of activation, a method of heating in a reducing atmosphere in a hydrogen stream is preferable.

(3) Method for Producing α, β-Unsaturated Carboxylic Acid Next, using the thus obtained catalyst for producing α, β-unsaturated carboxylic acid of the present invention, olefin or α, β-unsaturated A method for producing an α, β-unsaturated carboxylic acid by liquid phase oxidation of aldehyde with molecular oxygen will be described.

  Examples of the olefin as a raw material for liquid phase oxidation include propylene, isobutylene, 2-butene and the like. Examples of the raw α, β-unsaturated aldehyde include acrolein, methacrolein, crotonaldehyde (β-methylacrolein), and cinnamaldehyde (β-phenylacrolein). The raw material olefin or α, β-unsaturated aldehyde may contain some saturated hydrocarbons and / or lower saturated aldehydes as impurities.

  The α, β-unsaturated carboxylic acid produced by liquid phase oxidation is an α, β-unsaturated carboxylic acid having the same carbon skeleton as the olefin when the raw material is an olefin. When the raw material is an α, β-unsaturated aldehyde, it is an α, β-unsaturated carboxylic acid in which the aldehyde group of the α, β-unsaturated aldehyde is changed to a carboxyl group.

  The catalyst of the present invention is suitable for liquid phase oxidation for producing acrylic acid from propylene or acrolein, and methacrylic acid from isobutylene or methacrolein.

  Air is economical as the molecular oxygen source used in the reaction, but pure oxygen or a mixed gas of pure oxygen and air can also be used. If necessary, air or pure oxygen is converted into nitrogen, carbon dioxide, water vapor. It is also possible to use a mixed gas diluted with the same.

Although the solvent used for liquid phase oxidation is not specifically limited, For example, Water; Alcohols, such as tertiary butanol and cyclohexanol; Ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone; Acetic acid, propionic acid, n-butyric acid, iso- Organic acids such as butyric acid, n-valeric acid and iso-valeric acid; organic acid esters such as ethyl acetate and methyl propionate; hydrocarbons such as hexane, cyclohexane and toluene, or two or more selected from these groups The mixed solvent can be used. Among these, one or two or more solvents selected from the group consisting of alcohols, ketones, organic acids and organic acid esters are preferable, C _{2 to} C ₆ organic acids, tertiary butanol, and C ₃ to One type selected from the group consisting of C ₆ ketones or a mixture thereof is more preferable, and it is particularly preferable that any one of tertiary butanol, acetic acid and n-valeric acid is included. In addition, by using a mixed solvent of one or more solvents selected from the group consisting of alcohols, ketones, organic acids and organic acid esters and water, the results of the liquid phase oxidation reaction are further improved. Therefore, it is preferable. The amount of water at that time is not particularly limited, but is preferably 2% by mass or more, more preferably 5% by mass or more, and preferably 70% by mass or less, more preferably 50% by mass or less, based on the mass of the mixed solvent. It is. Although the solvent is desirably uniform, it may be used in a non-uniform state.

  The liquid phase oxidation reaction may be carried out in either a continuous type or a batch type, but in view of productivity, the continuous type is preferred industrially.

  The amount of the olefin or α, β-unsaturated aldehyde used as a raw material is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more with respect to 100 parts by mass of the solvent. Moreover, 20 mass parts or less are preferable, More preferably, it is 10 mass parts or less.

  The amount of molecular oxygen to be used is preferably at least 0.1 mol, more preferably at least 0.3 mol, particularly preferably at least 0.1 mol, based on 1 mol of the raw material olefin or α, β-unsaturated aldehyde. 5 moles or more. The amount of molecular oxygen used is preferably 30 mol or less, more preferably 25 mol or less, still more preferably 20 mol or less, particularly preferably 15 mol or less, and most preferably 10 mol or less. It is.

  The catalyst is preferably used in a state of being suspended in a reaction solution for performing liquid phase oxidation, but may be used in a fixed bed. The amount of catalyst used is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, particularly 100 parts by mass of the solution present in the reactor as the catalyst present in the reactor. Preferably it is 1 part by mass or more. The amount of the catalyst used is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less.

  The reaction temperature and reaction pressure are appropriately selected depending on the solvent used and the reaction raw materials. The reaction temperature is preferably 30 ° C or higher, more preferably 50 ° C or higher, still more preferably 60 ° C or higher, and particularly preferably 70 ° C or higher. The reaction temperature is preferably 200 ° C. or lower, more preferably 150 ° C. or lower. The reaction pressure is preferably atmospheric pressure (0 MPa) or more, more preferably 0.5 MPa or more, further preferably 2 MPa or more, preferably 10 MPa or less, more preferably 7 MPa or less, and further preferably 5 MPa or less. .

  When performing the reaction under pressure, it is preferable to use an autoclave having a stirring function.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to an Example. In the following Examples and Comparative Examples, “part” means “part by mass”.

(Analysis of raw materials and products)
Analysis of raw materials and products was performed using gas chromatography. In addition, reaction rate of olefin or α, β-unsaturated aldehyde, selectivity of α, β-unsaturated aldehyde to be produced, selectivity of polymer / oligomer to be produced, selectivity of α, β-unsaturated carboxylic acid to be produced And productivity is defined as follows.
Reaction rate of olefin or α, β-unsaturated aldehyde (%) = (B / A) × 100
Selectivity of α, β-unsaturated aldehyde (%) = (C / B) × 100
Selectivity of α, β-unsaturated carboxylic acid (%) = (D / B) × 100
Selectivity of polymer / oligomer (%) = (E / B) × 100
Productivity of α, β-unsaturated carboxylic acid (g / (g · h)) = F / (G × H)
Here, A is the number of moles of olefin or α, β-unsaturated aldehyde supplied, B is the number of moles of reacted olefin or α, β-unsaturated aldehyde, and C is the mole of α, β-unsaturated aldehyde produced. Number, D is the number of moles of α, β-unsaturated carboxylic acid produced, E is calculated by dividing the total mass (unit: g) of the polymer and oligomer by the molecular weight of the olefin or α, β-unsaturated aldehyde supplied. Of olefin or α, β-unsaturated aldehyde converted polymer and oligomer, F is the mass of the α, β-unsaturated carboxylic acid produced (unit: g), G is the mass of the metal contained in the catalyst used (Unit: g), H is the reaction time (unit: h). Here, in the case of the liquid phase oxidation reaction of α, β-unsaturated aldehyde, C / B = 0.

[Measurement of physical properties of carrier]
The pore volume and pore distribution of the support were measured by a constant volume method based on a nitrogen gas adsorption method using an automatic specific surface area / pore distribution measuring device TriStar 3000 (trade name) manufactured by Micromeritics. The pore diameter measurable by this method is in the range of approximately 1 to 100 nm, and all pore volumes and pore distributions described in the present invention are in the direction of increasing the relative pressure (adsorption equilibrium pressure / saturated vapor pressure). It was calculated based on the change in nitrogen adsorption amount (adsorption isotherm).

  In the above measurement, the total pore volume per unit mass of the support and the BET specific surface area were measured using the t-plot method. Moreover, the pore volume of pores (mesopores) having a pore diameter of 2 nm or more and 50 nm or less was calculated using the BJH method, and the ratio to the total pore volume was calculated.

[Example 1]
(Catalyst preparation)
1 part of palladium acetate (manufactured by NE Chemcat) was dissolved in 55 parts of an 88 mass% n-valeric acid aqueous solution. This solution was transferred to an autoclave, and synthetic raw material activated carbon manufactured by Kuraray Chemical Co., Ltd. (total pore volume was 0.64 cc / g, BET specific surface area was 1313 m ² / g, and the pore volume ratio of mesopore pores having a pore diameter of 2 nm to 50 nm) Was 7.8% of the total pore volume) and stirred. After introducing propylene to 0.5 MPa, the temperature was raised to 50 ° C. in 30 minutes and reduction was performed for 30 minutes. After completion of the reduction, the obtained supported palladium catalyst was filtered, washed with 88 mass% acetic acid aqueous solution and replaced, and then filtered to obtain a palladium-containing supported catalyst having a loading ratio of 10 mass%.

(Reaction evaluation)
In an autoclave, 135 parts of an 88% by mass aqueous acetic acid solution containing 200 ppm paramethoxyphenol (polymerization inhibitor) as a reaction solvent was added, and 5.5 parts of the palladium-containing supported catalyst having the above-mentioned supporting rate of 10% by mass was added. Furthermore, after adding 4.5 parts of methacrolein and sealing the container, the temperature was raised to 90 ° C. while stirring. Air was introduced to 3.2 MPa and methacrolein was oxidized for 20 minutes. The amount of molecular oxygen used in the oxidation reaction was 0.76 mol per 1 mol of methacrolein. After completion of the reaction, the autoclave was cooled to near room temperature, and then the reaction solution was taken out. The reaction solution from which the catalyst was separated was analyzed by gas chromatography.

  At this time, the reaction rate of methacrolein was 84.0%, the selectivity of methacrylic acid was 83.2%, and the productivity of methacrylic acid was 23.1 g / (g · h).

[Example 2]
Coconut shell raw material activated carbon manufactured by Kuraray Chemical Co., Ltd. (total pore volume is 0.49 cc / g, BET specific surface area is 988 m ² / g, and the ratio of pore volume of mesopores having a pore diameter of 2 nm to 50 nm is the total pore volume. Catalyst preparation and reaction evaluation were performed in the same manner as in Example 1 except that 10% of the volume) was used.

  At this time, the reaction rate of methacrolein was 89.7%, the selectivity of methacrylic acid was 84.7%, and the productivity of methacrylic acid was 25.2 g / (g · h).

[Example 3]
Coal raw material activated carbon made by Dainen Co. as a carrier (total pore volume is 0.46 cc / g, BET specific surface area is 753 m ² / g, and the pore volume ratio of mesopores with a pore diameter of 2 nm to 50 nm is the total pore volume. Catalyst preparation and reaction evaluation were performed in the same manner as in Example 1 except that 33%) was used.

  At this time, the reaction rate of methacrolein was 84.4%, the selectivity of methacrylic acid was 80.1%, and the productivity of methacrylic acid was 22.4 g / (g · h).

[Example 4]
Synthetic raw material activated carbon manufactured by Kuraray Chemical Co., Ltd. (total pore volume is 0.75 cc / g, BET specific surface area is 1613 m ² / g, and the pore volume ratio of mesopores having a pore diameter of 2 nm to 50 nm is the total pore volume. 4.0%) was used, and catalyst preparation and reaction evaluation were performed in the same manner as in Example 1.

  The reaction rate of methacrolein was 78.3%, methacrylic acid selectivity was 80.1%, and methacrylic acid productivity was 20.8 g / (g · h).

[Example 5]
Coal raw material activated carbon made by Dainen Co. as a carrier (total pore volume is 0.92 cc / g, BET specific surface area is 1345 m ² / g, and the pore volume ratio of mesopores with pore diameters of 2 nm to 50 nm is the total pore volume. The catalyst was prepared and the reaction was evaluated in the same manner as in Example 1 except that the reaction time was 11 minutes.

  At this time, the reaction rate of methacrolein was 90.3%, the selectivity of methacrylic acid was 77.3%, and the productivity of methacrylic acid was 42.1 g / (g · h).

[Example 6]
Synthetic raw material activated carbon manufactured by Kuraray Chemical Co., Ltd. (total pore volume is 1.27 cc / g, BET specific surface area is 2587 m ² / g, pore volume ratio of mesopores with pore diameters of 2 nm to 50 nm is the total pore volume The catalyst was prepared and the reaction was evaluated in the same manner as in Example 1, except that the reaction time was 11 minutes.

  At this time, the reaction rate of methacrolein was 89.5%, the selectivity of methacrylic acid was 78.3%, and the productivity of methacrylic acid was 42.3 g / (g · h).

[Example 7]
Charcoal raw material activated carbon made by Norit as a carrier (total pore volume is 1.30 cc / g, BET specific surface area is 1692 m ² / g, and the pore volume ratio of mesopores having a pore diameter of 2 nm to 50 nm is the total pore volume 58%) and the reaction time was 15 minutes, and the catalyst preparation and reaction evaluation were performed in the same manner as in Example 1.

  At this time, the reaction rate of methacrolein was 86.9%, the selectivity of methacrylic acid was 76.2%, and the productivity of methacrylic acid was 29.3 g / (g · h).

[Comparative Example 1]
Coal raw material activated carbon manufactured by Kansai Thermochemical Co., Ltd. as a carrier (total pore volume is 1.61 cc / g, BET specific surface area is 3174 m ² / g, and the ratio of the pore volume of mesopores having a pore diameter of 2 nm to 50 nm is the total pore volume. Catalyst preparation and reaction evaluation were performed in the same manner as in Example 1 except that 35% of the volume) was used.

  At this time, the reaction rate of methacrolein was 35.0%, the selectivity of methacrylic acid was 24.3%, and the productivity of methacrylic acid was 2.8 g / (g · h).

[Comparative Example 2]
Wood raw material activated carbon manufactured by Norit as a carrier (total pore volume is 1.61 cc / g, BET specific surface area is 1680 m ² / g, and the pore volume ratio of mesopores having a pore diameter of 2 nm to 50 nm is the total pore volume. The catalyst was prepared and the reaction was evaluated in the same manner as in Example 1 except that 68%) was used.

  At this time, the reaction rate of methacrolein was 83.1%, the selectivity of methacrylic acid was 54.5%, and the productivity of methacrylic acid was 15.0 g / (g · h).

[Comparative Example 3]
Synthetic raw material activated carbon manufactured by Kuraray Chemical Co., Ltd. (total pore volume is 0.37 cc / g, BET specific surface area is 690 m ² / g, pore volume ratio of mesopores with pore diameters of 2 nm to 50 nm is the total pore volume 2.7%) was used, and the catalyst was prepared and reacted in the same manner as in Example 1.

  At this time, the reaction rate of methacrolein was 50.5%, the selectivity of methacrylic acid was 65.2%, and the productivity of methacrylic acid was 10.9 g / (g · h).

  Table 1 shows a list of physical properties and reaction results of the carriers used in Examples 1 to 7 and Comparative Examples 1 to 3. In Examples 1 to 7 using a carrier having a total pore volume of 0.40 to 1.50 cc / g, it was found that the selectivity and productivity of methacrylic acid were good. Furthermore, in Examples 1-4 using the support | carrier with a small total pore volume, it turned out that methacrylic acid selectivity is especially favorable. In Examples 5 to 7 using a carrier having a large total pore volume, it was found that the productivity of methacrylic acid was particularly good.

[Example 8]
(Catalyst preparation)
1.05 parts of palladium acetate (manufactured by NE Chemcat) was dissolved in 20 parts of acetic acid. 10 parts of silica support (total pore volume is 0.68 cc / g, BET specific surface area is 450 m ² / g, pore volume ratio of mesopores with a pore diameter of 2 nm to 50 nm is 100% of the total pore volume) After adding an acetic acid solution and shaking, evaporation was performed. Then, it baked at 450 degreeC in the air for 3 hours. The obtained catalyst precursor was added to 13 parts of a 37 mass% formaldehyde aqueous solution. The mixture was heated to 70 ° C., stirred and held for 2 hours, suction filtered, and then filtered and washed with water and a 75 mass% t-butanol aqueous solution to obtain a palladium-containing supported catalyst having a loading ratio of 5 mass%.

(Reaction evaluation)
The autoclave was sealed with 100% of a 75% by weight aqueous t-butanol solution and 0.02 part of p-methoxyphenol as the reaction solvent, and the total amount of the catalyst obtained by the above method (10.5 parts). Next, 2.75 parts of isobutylene was introduced, stirring (rotation speed: 1000 rpm) was started, and the temperature was raised to 90 ° C. After completion of the temperature increase, nitrogen was introduced into the autoclave to an internal pressure of 2.3 MPa, and then compressed air was introduced to an internal pressure of 4.6 MPa. When the internal pressure decreased by 0.1 MPa during the reaction, the operation of introducing oxygen and increasing the internal pressure by 0.1 MPa was repeated 10 times. The reaction was terminated when the internal pressure decreased by 0.1 MPa after the 10th introduction of oxygen. The reaction time at this time was 56 minutes. The amount of molecular oxygen used in the oxidation reaction was 3.48 moles per mole of isobutylene.

  After completion of the reaction, the inside of the autoclave was ice-cooled in an ice bath. A gas collection bag was attached to the gas outlet of the autoclave, and the pressure in the reactor was released while collecting the gas that was opened by opening the gas outlet. The reaction solution containing the catalyst was taken out from the autoclave, the catalyst was separated with a membrane filter, and the reaction solution was recovered. The collected reaction liquid and the collected gas were analyzed by gas chromatography, and the reaction rate and selectivity were calculated.

  At this time, the reaction rate of isobutylene was 90.7%, methacrolein selectivity 28.2%, methacrylic acid selectivity 28.6%, and methacrylic acid productivity 2.2 g / (g · h).

[Example 9]
The support used is a Y-type zeolite having a silica / alumina (SiO ₂ / Al ₂ O ₃ ) molar ratio of 200 (total pore volume of 0.50 cc / g, BET specific surface area of 629 m ² / g, pore diameter of 2 nm or more) A Y-zeolite-supported palladium-containing catalyst on which palladium metal was supported was obtained in the same manner as in Example 8 except that the proportion of the mesopore pores of 50 nm or less was changed to 42% of the total pore volume). It was.

  The reaction was carried out in the same manner as in Example 8 except that the reaction time was 38 minutes using the catalyst obtained above. At this time, the reaction rate of isobutylene was 75.2%, methacrolein selectivity was 49.9%, methacrylic acid selectivity was 19.0%, and methacrylic acid productivity was 1.9 g / (g · h).

[Comparative Example 4]
The support used is an H-ZSM-5 type zeolite having a silica / alumina (SiO ₂ / Al ₂ O ₃ ) molar ratio of 485 (total pore volume is 0.20 cc / g, BET specific surface area is 343 m ² / g, H-ZSM-5 zeolite carrying palladium metal in the same manner as in Example 8 except that the ratio of the pore volume of mesopores having a pore diameter of 2 nm to 50 nm was changed to 29% of the total pore volume) A supported palladium-containing catalyst was obtained.

  The reaction was carried out in the same manner as in Example 8 except that the reaction time was 107 minutes using the catalyst obtained above. The reaction rate of isobutylene was 67.4%, methacrolein selectivity 59.1%, methacrylic acid selectivity 15.4%, and methacrylic acid productivity 0.5 g / (g · h).

  Table 2 shows a list of physical properties and reaction results of the carriers used in Examples 8 and 9 and Comparative Example 4. In Examples 8 and 9 using a carrier having a total pore volume of 0.40 to 1.50 cc / g, it was found that the selectivity and productivity of methacrylic acid were good.

  As described above, it was found that by using the catalyst of the present invention, α, β-unsaturated carboxylic acid can be produced from olefin or α, β-unsaturated aldehyde by liquid phase oxidation with good reaction results.

Claims (7)

  A catalyst for producing an α, β-unsaturated carboxylic acid from an olefin or an α, β-unsaturated aldehyde by liquid phase oxidation, wherein the total pore volume measured by a nitrogen gas adsorption method is 0.40 to 1. A catalyst for producing an α, β-unsaturated carboxylic acid, wherein a metal is supported on a carrier of 50 cc / g.   The catalyst for producing an α, β-unsaturated carboxylic acid according to claim 1, wherein the total pore volume of the carrier measured by a nitrogen gas adsorption method is 0.40 to 0.80 cc / g.   The α, β-unsaturated carboxylic acid according to claim 2, wherein the ratio of the pore volume of mesopores having a pore diameter of 2 nm or more and 50 nm or less measured by a nitrogen gas adsorption method of the carrier is 40% or less of the total pore volume. Catalyst for production.   The catalyst for producing an α, β-unsaturated carboxylic acid according to claim 1, wherein the total pore volume of the carrier measured by a nitrogen gas adsorption method is 0.80 to 1.50 cc / g.   The α, β-unsaturated carboxylic acid according to claim 4, wherein a ratio of the pore volume of mesopores having a pore diameter of 2 nm or more and 50 nm or less measured by a nitrogen gas adsorption method of the carrier is 10% or more of the total pore volume. Catalyst for production.   A method for producing a catalyst for producing an α, β-unsaturated carboxylic acid according to any one of claims 1 to 5, wherein the α, β-unsaturated carboxylic acid is produced by reducing a metal compound with a reducing agent in the presence of the carrier. For producing a catalyst for use. An α, β-unsaturation which oxidizes an olefin or α, β-unsaturated aldehyde in the liquid phase with molecular oxygen in the presence of the catalyst for producing an α, β-unsaturated carboxylic acid according to claim 1. A method for producing carboxylic acid.