JP2005305243A - CATALYST FOR PRODUCING alpha, beta-UNSATURATED ALDEHYDE AND/OR alpha, beta-UNSATURATED CARBOXYLIC ACID, PRODUCTION METHOD THEREOF AND USAGE THEREOF - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst for producing α, β-unsaturated aldehyde and/or α, β-unsaturated carboxylic acid having high productivity, to provide a production method of the catalyst, and to provide a production method of α, β-unsaturated aldehyde and/or α, β-unsaturated carboxylic acid using the catalyst. <P>SOLUTION: The catalyst for producing α, β-unsaturated aldehyde and/or α, β-unsaturated carboxylic acid used for liquid phase oxidation of olefin with molecular oxygen comprises at least palladium, activated carbon and hydrophobic material of contact angle for water ≥30°. In the production method of the catalyst having at least a reduction process, at least palladium in an oxidized state, activated carbon and hydrophobic material of contact angle for water ≥30° are used as the starting material. α, β-unsaturated aldehyde and/or α, β-unsaturated carboxylic acid are produced by oxidizing olefin in liquid phase with molecular oxygen under the presence of the catalyst for production of α, β-unsaturated aldehyde and/or α, β-unsaturated carboxylic acid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a catalyst for the production of α, β-unsaturated aldehydes and / or α, β-unsaturated carboxylic acids, its production method and its use, more specifically, liquid phase oxidation of olefins with molecular oxygen. Catalyst for producing α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid, process for producing the same, and α, β-unsaturated aldehyde and / or α, β-unsaturated using the catalyst The present invention relates to a method for producing carboxylic acid and the like.

In order to produce α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid by liquid phase oxidation of olefin with molecular oxygen, palladium-containing catalysts are proposed in Patent Documents 1 and 2. . These patent documents describe that palladium is supported on activated carbon and used as a catalyst. However, the activated carbon-supported palladium catalyst containing a hydrophobic substance is not described.
JP 60-155148 A JP 60-139341 A

  When the present inventor produced acrolein and acrylic acid from propylene using a palladium-containing catalyst produced according to the method described in Examples of Patent Documents 1 and 2, In addition to the products (acetaldehyde, acetone, acrolein, acetic acid, carbon dioxide), it can be seen that a large number of various polymers and oligomers are by-produced, and the actual yield of acrylic acid including these by-products is as follows. It was found to be lower than that described in the Examples. As described above, the catalysts produced by the methods described in Patent Documents 1 and 2 are not yet sufficient in performance for producing α, β-unsaturated carboxylic acid, and development of a catalyst with higher productivity has been desired. The object of the present invention is to produce α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid at high production in the production of α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid from olefin. It is an object of the present invention to provide an efficient α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid production method using the catalyst.

  As a result of intensive studies to achieve the above problems, the present inventors have found that the above problems can be solved by adding a hydrophobic substance to the catalyst, and the present invention has been completed.

  That is, the gist of the present invention is (1) an α, β-unsaturated aldehyde used for liquid phase oxidation of olefins with molecular oxygen, comprising at least palladium, activated carbon, and a hydrophobic substance having a contact angle with water of 30 ° or more. / Or a catalyst for producing an α, β-unsaturated carboxylic acid. (2) The catalyst for producing an α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid according to (1), wherein the hydrophobic substance is in a range of 30% by mass or less with respect to the activated carbon. (3) The raw material is at least oxidized palladium, activated carbon and a hydrophobic substance having a contact angle with water of 30 degrees or more, and has at least a step of reducing the palladium (1) or (2 ), A method for producing a catalyst for producing an α, β-unsaturated aldehyde and / or an α, β-unsaturated carboxylic acid. (4) An α, β-unsaturated aldehyde according to (3), wherein a solution containing at least oxidized palladium and activated carbon are mixed, and then the palladium is reduced, and then a hydrophobic substance is mixed. / Or a method for producing a catalyst for producing an α, β-unsaturated carboxylic acid. (5) Liquid phase oxidation of olefin with molecular oxygen in the presence of the α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid production catalyst described in (1) or (2). A method for producing an α, β-unsaturated aldehyde and / or an α, β-unsaturated carboxylic acid.

  According to the present invention, highly productive α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid production catalyst, its production method and efficient α, β-unsaturated aldehyde and / or α , Β-unsaturated carboxylic acid production method can be provided.

  The catalyst of the present invention is for liquid phase oxidation of olefins with molecular oxygen to produce α, β-unsaturated aldehydes and / or α, β-unsaturated carboxylic acids (hereinafter also simply referred to as liquid phase oxidation). The catalyst is a catalyst for producing α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid containing at least palladium, activated carbon and a hydrophobic substance having a contact angle with water of 30 ° or more.

  Palladium, activated carbon, and a hydrophobic substance are essential, and if one of these components is insufficient, the catalyst performance decreases. As the function of each component, palladium is a catalytically active component, activated carbon is a catalyst carrier, and a hydrophobic substance promotes the adsorption of the reaction gas to the active site of the olefin, and the product α, β-unsaturated aldehyde or α, β- The purpose is to promote elimination of the unsaturated carboxylic acid from the active site.

  The usage-amount of palladium is 0.1 mass% or more normally with respect to activated carbon mass, Preferably it is 0.5 mass% or more, More preferably, it is 1 mass% or more. Moreover, an upper limit is 40 mass% or less normally, Preferably it is 30 mass% or less, More preferably, it is 20 mass% or less. Palladium is essential as an active ingredient, but any metal other than palladium may be included.

  As described above, activated carbon functions as a catalyst carrier, but it is necessary for improving the surface area of precious metals and realizing high dispersion, and also for controlling acid sites and base sites.

  The hydrophobic substance needs to have a contact angle with water of 30 degrees or more, preferably 50 degrees or more, more preferably 70 degrees or more in order to exhibit sufficient hydrophobicity. As shown in FIG. 1, the contact angle refers to a contact angle between a solid surface and a liquid droplet contacting the solid surface. In the case of a water contact angle, the droplet is water. The contact angle is measured using a commercially available contact angle measuring device. The measuring method is described in “Light metal, 39, 136, 1989”.

  If the water contact angle of the hydrophobic substance is 30 ° or more, the adsorption of the reaction gas to the active site of the olefin and the activity of the product α, β-unsaturated aldehyde or α, β-unsaturated carboxylic acid Desorption from the point is promoted, and the catalytic function is improved.

  The hydrophobic substance is not particularly limited as long as it has a contact angle with water of 30 ° or more, and examples thereof include fluororesin, polyolefin, vinyl chloride resin, and fluororesin is particularly preferable. Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene-fluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and ethylene-tetrafluoroethylene. A copolymer (ETFE), polyvinylidene fluoride (PVDF) and the like can be mentioned, and PTFE and FEP are preferred. Their water contact angles are, in order, 114 degrees, 109 degrees, 115 degrees, 105 degrees, and 80 degrees, all of which are 30 degrees or more.

  The content of the hydrophobic substance is usually 30% by mass or less and 1% by mass or more with respect to the activated carbon, and is preferably in the range of 5 to 20% by mass. Within this range, the effect of improving the catalytic activity is particularly good.

Next, the manufacturing method of the catalyst of this invention is demonstrated in detail.
As the raw material of this catalyst, at least oxidized palladium, activated carbon, and a hydrophobic substance having a contact angle with water of 30 degrees or more are used.

  The oxidized palladium is not particularly limited as long as it is a compound containing palladium in the oxidized state. Nato and the like. Of these, noble metal chlorides, acetates and nitrates are preferred.

  Activated carbon is usually produced by a process of carbonization, granulation, activation, washing, drying and pulverization, but the production process of the activated carbon used in the present invention is not particularly limited. There is no particular limitation on the carbonaceous material that is the raw material of the activated carbon, and various raw materials such as coconut shell, coal, wood, and 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, and dried before use. Of the impurities contained in the product activated carbon, chlorine is not preferable because it may adversely affect the catalyst performance. Accordingly, 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. Among them, the finer is preferable because the dispersibility in the reaction liquid is increased and the catalytic activity is improved. However, the finer the particle, the harder the solid-liquid separation is. Activated carbon is good.

The specific surface area of the activated carbon is preferably 100 m ² / g or more, more preferably 300 m ² / g or more, preferably 5000 m ² / g or less, more preferably 4000 m ² / g or less. The smaller the specific surface area of the activated carbon, the more the catalyst having useful components supported on the surface can be produced, and the larger the activated carbon, the more the catalyst carrying more palladium can be produced.

  The pore volume of the activated carbon is preferably from 0.35 to 0.8 cc / g, more preferably from 0.4 to 0.7 cc / g, as determined by the nitrogen gas adsorption method. A carrier having a pore volume ratio of 1 nm or less in pore diameter of 50% or more of the total pore volume is preferable. By using a carrier having pores in this region, the desired product can be obtained with good selectivity with little by-product formation.

  As the hydrophobic substance having a contact angle with water of 30 degrees or more, a powder or a dispersion can be used. The dispersion is a dispersion of fine powder in a liquid, and water, isopropyl alcohol, or the like is used as the liquid.

  The particle size of the hydrophobic substance is preferably 10 nm to 50 μm, more preferably 100 nm to 10 μm. Within this range, it is preferable because it is easy to bind to the carrier and it is difficult to inhibit parasite which is the active site.

  In the production of the catalyst of the present invention, reduction is performed by mixing at least a solution containing palladium in an oxidized state and activated carbon. The reduction may be performed in the gas phase, but is preferably performed in the liquid phase. When performing in a liquid phase, after dissolving a noble metal compound in a solvent, the noble metal in the noble metal compound is reduced using a reducing agent.

  The reduction temperature varies depending on the precious metal compound, the reducing agent, etc. used, but is usually −5 ° C. or higher, preferably 15 ° C. or higher. Moreover, it is normally performed at 150 ° C. or lower, preferably 80 ° C. or lower. The reduction time is usually 0.1 hour or longer, preferably 0.25 hour or longer, more preferably 0.5 hour or longer. Moreover, it is 4 hours or less normally, Preferably it is 3 hours or less, More preferably, it is 2 hours or less.

  The solvent used in the reduction in the liquid phase is preferably water, but alcohols such as ethanol, 1-propanol, 2-propanol, n-butanol, and t-butanol; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone Ketones such as acetic acid, n-valeric acid, iso-valeric acid and the like, and organic solvents such as hydrocarbons such as heptane, hexane, cyclohexane and the like can be used alone or in combination. Moreover, it is preferable to use the mixed solvent of these organic solvents and water. In particular, when palladium chloride is used as the palladium compound, a mixed solvent of ethanol and water, a mixed solvent of acetone and water, or a mixed solvent of acetic acid and water is preferable.

  The reducing agent is selected from the group consisting of methanol, ethanol, 2-propanol, hydrazine, formalin, formic acid, sodium formate, oxalic acid, sodium borohydride, hydrogen, ethylene, propylene, 1-butene, 2-butene and isobutylene. 1 or more selected from the group consisting of ethanol, 2-propanol, hydrazine, formalin, sodium borohydride, hydrogen, ethylene, propylene, 1-butene, 2-butene and isobutylene. One or more compounds, most preferably one or more compounds selected from the group consisting of hydrazine, formalin, hydrogen and propylene. These reducing agents may be used in combination with other reducing agents.

  When the reducing agent is a gas, it is preferably carried out in a pressurizing apparatus such as an autoclave in order to increase the solubility in the solution. At that time, the inside of the pressurizer is pressurized with a reducing agent. The pressure is usually 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 apparatus for reducing the palladium compound is not limited, and the reduction can be performed by adding the reducing agent to the palladium compound solution. Although the usage-amount of a reducing agent at this time is not specifically limited, It is about 1-100 mol normally with respect to 1 mol of palladium atoms.

  It is preferable that the hydrophobic substance is first mixed with a solution containing at least oxidized palladium and activated carbon and then mixed after reduction. Although the solution at the time of mixing is not specifically limited, The liquid used for the reduction reaction can also be used as it is. The mixing temperature is preferably 5 to 100 ° C. for 5 to 120 minutes.

  After mixing, the catalyst is washed, filtered, and used for the reaction. For washing, water, warm water, acetone, a reaction solvent, or the like is used. Filtration is preferably performed in an inert gas atmosphere such as nitrogen, carbon dioxide, or argon. By washing, for example, impurities derived from raw material salts such as chloride, acetate radical, nitrate radical, and sulfate radical are removed. The cleaning method and the number of times are not particularly limited. However, depending on the impurities, the reaction may be hindered. Therefore, it is preferable that the cleaning is performed to such an extent that the impurities can be sufficiently removed.

  Next, a method for producing an α, β-unsaturated aldehyde and / or an α, β-unsaturated carboxylic acid by liquid phase oxidation of olefin with molecular oxygen will be described.

  Examples of the raw material olefin include propylene, isobutylene, 1-butene, and 2-butene. Among these, propylene and isobutylene are preferable. The raw material olefin may contain a small amount of saturated hydrocarbon, lower saturated aldehyde and the like as impurities.

  The α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid produced by liquid phase oxidation is an α, β-unsaturated aldehyde and / or α, β- having the same carbon skeleton as the raw material olefin. Unsaturated carboxylic acid. The catalyst of the present invention is suitable for liquid phase oxidation for producing acrolein or acrylic acid from propylene and methacrolein or methacrylic acid from isobutylene.

  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.

  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.

  Examples of the reaction solvent for the liquid phase oxidation reaction include tertiary butanol, cyclohexanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, n-valeric acid, iso-valeric acid, It is preferable to use at least one compound selected from the group consisting of ethyl acetate and methyl propionate. Among these, at least one compound selected from the group consisting of tertiary butanol, methyl isobutyl ketone, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, n-valeric acid and iso-valeric acid is more preferable. In addition, in order to produce an α, β-unsaturated carboxylic acid with high selectivity, it is preferable to coexist water in these organic solvents. The amount of water to coexist is not particularly limited, but is usually 2% by mass or more, preferably 5% by mass or more, based on the total mass of the organic solvent and water. Moreover, it is 70 mass% or less normally, Preferably it is 50 mass% or less. The mixture of the organic solvent and water is desirably in a uniform state, but may be in a non-uniform state.

  The concentration of the olefin as a raw material for the reaction is usually 0.1% by mass or more, preferably 0.5% by mass or more, with respect to the solvent present in the reactor. Moreover, it is 20 mass% or less normally, Preferably it is 10 mass% or less.

  The amount of molecular oxygen to be used is usually 0.1 mol or more, preferably 0.3 mol or more, more preferably 0.5 mol or more with respect to 1 mol of olefin as a raw material. Moreover, it is 20 mol or less normally, Preferably it is 15 mol or less, More preferably, it is 10 mol or less.

  Usually, the catalyst of the present invention is used in a state suspended in a reaction solution, but may be used in a fixed bed. The amount used is usually 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more with respect to the solution present in the reactor. Moreover, it is 30 mass% or less normally, 20 mass% or less is more preferable, and 15 mass% or less is further more preferable.

  The reaction temperature and reaction pressure of the liquid phase oxidation reaction are appropriately selected depending on the solvent used and the reaction raw materials. The reaction temperature is generally 30 to 200 ° C, preferably 50 ° C or higher, and preferably 150 ° C or lower. The reaction pressure is generally atmospheric pressure (0 MPa) to 10 MPa, preferably 0.5 MPa or more, and preferably 5 MPa or less.

  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. The reaction rate of isobutylene, the methacrolein (MAL), the selectivity of methacrylic acid (MAA) and the polymer / oligomer, and the yield and productivity of MAA are defined as follows.
Reaction rate of isobutylene (%) = (B / A) × 100
Selectivity (%) of methacrolein (MAL) = (C / B) × 100
Methacrylic acid (MAA) selectivity (%) = (D / B) × 100
Selectivity of polymer / oligomer (%) = (E / B) × 100
MAL yield (%) = (C / A) × 100
MAA yield (%) = (D / A) × 100
MAL productivity (g / g-Pd / h) = F / (H × I)
MAA productivity (g / g−Pd / h) = G / (H × I)
Productivity of MAL + MAA (g / g−Pd / h) = (F + G) / (H × I)

here,
A is the number of moles of isobutylene supplied,
B is the number of moles of reacted isobutylene,
C is the number of moles of methacrolein produced,
D is the number of moles of methacrylic acid produced,
E is the number of moles of polymer and oligomer in terms of isobutylene calculated by dividing the total mass (unit: g) of the produced polymer and oligomer by the molecular weight of the supplied isobutylene,
F is the mass of the produced methacrolein (unit: g),
G is the mass of the generated methacrylic acid (unit: g),
H is the mass of palladium contained in the catalyst (unit: g),
I is the reaction time (unit: hours).

[Example 1]
(Catalyst preparation)
1.055 parts of palladium acetate was dissolved by heating in 60 parts of an 88% by mass n-valeric acid aqueous solution. To this solution, 5.0 parts of activated carbon (specific surface area of 780 m ^{2 /} g) was added and charged in an autoclave and sealed. Stirring was started, the temperature of the internal liquid was cooled to 10 ° C. or lower, propylene gas was introduced to an internal pressure of 0.5 MPa, and then held at 50 ° C. for 1 hour for reduction. After 1 hour, the temperature of the internal liquid was lowered to 20 ° C. or lower, and then the internal pressure was released. Thereafter, 0.25 part of PTFE powder (average particle size 5 μm) was added and stirred for 1 hour. Thereafter, the mixture was suction filtered and washed several times with 75% by mass tertiary butanol to obtain an activated carbon-supported palladium catalyst. In addition, almost no loss of the active component of the catalyst was recognized at the time of preparation. The obtained catalyst had a palladium loading of 10% by mass and a PTFE content of 5% by mass with respect to the activated carbon.

(Reaction evaluation)
Into the autoclave, the total amount of the palladium catalyst supported on the activated carbon obtained by the above method and 75 parts of a 75% by mass tertiary butanol aqueous solution as a reaction solvent were put, and the autoclave was sealed. Next, 2.0 parts of isobutylene was introduced, stirring (rotation speed: 100 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 2.4 MPa, and then compressed air was introduced to an internal pressure of 4.8 MPa. When the internal pressure decreased by 0.1 MPa during the reaction (internal pressure 4.7 MPa), the operation of introducing 0.1 MPa of oxygen was repeated. The pressure immediately after introduction is 4.8 MPa. The reaction was performed for 60 minutes.
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 by a membrane filter, and only the reaction solution was recovered. The collected reaction liquid and the collected gas were analyzed by gas chromatography. The results are shown in Table 1. It was found that the productivity of MAL and / or MAA was high, and that the resulting catalyst had a high productivity of MAL and / or MAA.

[Example 2]
A catalyst was prepared in the same manner as in Example 1 except that the amount of PTFE used was 0.5 part. The obtained catalyst had a palladium loading ratio of 10% by mass and a PTFE content of 10% by mass with respect to the activated carbon. Reaction evaluation was performed in the same manner as in Example 1. The results are shown in Table 1. As in Example 1, the productivity of MAL and / or MAA was high, and the productivity of MAL and / or MAA of the obtained catalyst was found to be high.

[Example 3]
A catalyst was prepared in the same manner as in Example 1 except that the amount of PTFE used was changed to 0.75 part. The obtained catalyst had a palladium loading ratio of 10% by mass and a PTFE content of 15% by mass with respect to the activated carbon. Reaction evaluation was performed in the same manner as in Example 1. The results are shown in Table 1. As in Example 1, the productivity of MAL and / or MAA was high, and the productivity of MAL and / or MAA of the obtained catalyst was found to be high.

[Example 4]
A catalyst was prepared in the same manner as in Example 1 except that the amount of PVDF used was changed to 0.5 parts instead of the amount of PTFE used was 0.25 parts. The obtained catalyst had a palladium loading ratio of 10% by mass and a PVDF content of 10% by mass with respect to the activated carbon. Reaction evaluation was performed in the same manner as in Example 1. The results are shown in Table 1. As in Example 1, the productivity of MAL and / or MAA was high, and the productivity of MAL and / or MAA of the obtained catalyst was found to be high.

[Comparative Example 1]
A catalyst was prepared in the same manner as in Example 1 except that PTFE powder was not added. The obtained catalyst had a palladium loading of 10% by mass with respect to the activated carbon. Reaction evaluation was performed in the same manner as in Example 1. The results are shown in Table 1. The productivity of MAL and / or MAA was low.

It is a figure which shows the definition of the water contact angle of the solid used for this invention.

Explanation of symbols

1 Contact angle 2 Water 3 Solid 4 Air

Claims (5)

  [Alpha], [beta] -unsaturated aldehyde and / or [alpha], [beta] -unsaturated carboxylic acid used for liquid phase oxidation of olefins with molecular oxygen including at least palladium, activated carbon and a hydrophobic substance having a contact angle with water of 30 degrees or more Catalyst for production.   The catalyst for producing an α, β-unsaturated aldehyde and / or α, β-unsaturated carboxylic acid according to claim 1, wherein the hydrophobic substance is in a range of 30% by mass or less based on the activated carbon.   3. The α, according to claim 1, comprising at least a step of reducing palladium by using at least oxidized palladium, activated carbon and a hydrophobic substance having a contact angle with water of 30 degrees or more as raw materials. A method for producing a catalyst for producing a β-unsaturated aldehyde and / or an α, β-unsaturated carboxylic acid.   The α, β-unsaturated aldehyde and / or α according to claim 3, wherein a solution containing at least oxidized palladium and activated carbon are mixed, and then the palladium is reduced, and then a hydrophobic substance is mixed. , Β-Unsaturated carboxylic acid production catalyst production method.   An α, β-unsaturated aldehyde and / or an α, β-unsaturated carboxylic acid production catalyst according to claim 1 or 2, wherein the olefin is subjected to liquid phase oxidation with molecular oxygen in the presence of the catalyst. A method for producing a β-unsaturated aldehyde and / or an α, β-unsaturated carboxylic acid.

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