JP2002361086A - Catalyst for carboxylic acid ester synthesis and method for producing carboxylic acid ester - Google Patents

Abstract

(57) [Problem] To provide a catalyst for synthesizing a carboxylic acid ester which is more excellent in catalytic activity. The catalyst is used in a reaction for synthesizing a carboxylic acid ester by reacting an aldehyde and an alcohol in the presence of oxygen, wherein ultrafine gold particles having an average particle diameter of 6 nm or less are supported on an inorganic oxide carrier. The present invention also relates to a catalyst for synthesizing a carboxylic acid ester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for carboxylic acid ester synthesis and a method for producing carboxylic acid ester.

[0002]

2. Description of the Related Art Carboxylic esters such as acrylic esters and methacrylic esters are industrially important compounds as polymerization monomers used as raw materials for various synthetic resins.

As a method of synthesizing a carboxylic acid ester from an aldehyde, a method of reacting an aldehyde (acrolein, methacrolein, etc.) with an alcohol (methanol, etc.) in the presence of oxygen is particularly known. And
In this reaction, it is known to use a specific metal as a catalytically active component and use a catalyst in which the metal is supported on a carrier.

For example, in producing a carboxylic acid ester by reacting an aldehyde with an alcohol in the presence of oxygen, a carboxylic acid ester characterized by using a catalyst comprising palladium and at least one of lead and a lead compound. Is known (JP-B-57-358).
No. 59) A method for producing a carboxylate by reacting an aldehyde and an alcohol in the presence of an oxygen-containing gas to produce a carboxylate, wherein the reaction is carried out in the presence of a catalyst having gold supported on a carrier. A method has been proposed (JP-A-2000-154164).

[0005]

However, all of the catalysts mentioned in the prior art still have low catalytic activity, and further improvement is required to synthesize carboxylic acid esters more efficiently.

Accordingly, a main object of the present invention is to provide a catalyst for synthesizing a carboxylate ester which is more excellent in catalytic activity.

[0007]

The inventor of the present invention has conducted intensive studies in order to solve the problems of the prior art.
The inventors have found that a material comprising a combination of ultrafine gold particles and an inorganic oxide carrier can achieve the above object, and have completed the present invention.

That is, the present invention relates to the following catalyst for carboxylic acid ester synthesis and a method for producing a carboxylic acid ester.

1. A catalyst used in a reaction for synthesizing a carboxylate by reacting an aldehyde and an alcohol in the presence of oxygen, wherein the ultrafine gold particles having an average particle diameter of 6 nm or less are supported on an inorganic oxide carrier. A catalyst for the synthesis of carboxylic acid esters.

[0010] 2. The inorganic oxide carrier is composed of Mg, Ca, S
r, Ba, Al, Si, Ti, V, Cr, Mn, Fe,
Co, Ni, Cu, Zn, Zr, Nb, Sn, Pb, L
2. The catalyst for synthesizing a carboxylic acid ester according to the above item 1, comprising an oxide containing at least one element of a and Ce.

3. The inorganic oxide carrier is composed of Mg, Ca, S
r, Ba, Al, Ti, V, Cr, Mn, Fe, Co,
2. The catalyst for synthesizing a carboxylic acid ester according to the above item 1, comprising an oxide containing at least one of Ni, Cu, Zn, Zr, Nb, Sn, Pb, La and Ce and Si.

4. When the inorganic oxide carrier is Mg, Al, T
After impregnating silica with an aqueous solution of a water-soluble compound containing at least one of i, Zn, Zr, Nb, Sn, Pb, La and Ce, the oxide is obtained by calcining the obtained impregnated body. Item 2. The carboxylic acid ester synthesis catalyst according to the above item 1.

5. Item 5. The catalyst for synthesizing a carboxylic acid ester according to any one of Items 1 to 4, which is obtained by mixing an aqueous solution of a water-soluble compound containing gold and an inorganic oxide carrier, and then baking the collected solid.

6. 6. A method for producing a carboxylic acid ester, which comprises reacting an aldehyde with an alcohol in the presence of the catalyst for synthesizing a carboxylic acid ester according to any one of the above items 1 to 5 and oxygen.

[0015] 7. Item 2. The catalyst for synthesizing a carboxylic acid ester according to Item 1, wherein the aldehyde is at least one of acrolein and methacrolein.

8. Item 2. The carboxylic acid ester synthesis catalyst according to Item 1, wherein the alcohol is at least one of methanol and ethanol.

9. Item 7. The method according to Item 6, wherein the aldehyde is at least one of acrolein and methacrolein.

10. Item 7. The method according to Item 6, wherein the alcohol is at least one of methanol and ethanol.

11. The inorganic oxide carrier is composed of Mg, Ca, S
r, Ba, Al, Ti, V, Cr, Mn, Fe, Co,
An oxide obtained by impregnating silica with an aqueous solution of a water-soluble compound containing at least one of Ni, Cu, Zn, Zr, Nb, Sn, Pb, La and Ce, and then calcining the obtained impregnated body Item 4. The catalyst for synthesizing a carboxylic acid ester according to Item 1, comprising:

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Carboxylic acid ester synthesis catalyst The carboxylic acid ester synthesis catalyst of the present invention is a catalyst used for a reaction for synthesizing a carboxylic acid ester by reacting an aldehyde and an alcohol in the presence of oxygen, and has an average particle diameter of 6 nm or less. Characterized in that ultrafine gold particles are supported on an inorganic oxide carrier.

Gold (Au) exists as ultrafine gold particles having an average particle diameter of 6 nm or less (preferably 5 nm or less). By setting the average particle diameter to 6 nm or less, a high catalytic activity can be achieved by a synergistic effect with the inorganic oxide carrier. The lower limit of the average particle diameter is not particularly limited, but may be about 1 nm from the viewpoint of physical stability. The average particle diameter of the metal particles (ultrafine gold particles) in the present invention is determined by measuring the average particle diameter of the metal particles on the carrier by a transmission electron microscope (T
The arithmetic mean value of the particle diameter of 100 particles arbitrarily selected by observation by EM) is shown.

As the inorganic oxide carrier, those used as catalyst carriers used in conventional carboxylic acid ester synthesis or commercially available products can be used, and there is no particular limitation. Further, those obtained by a known production method can also be used. For example, oxides, metal oxides (silica, alumina,
Titania, zirconia, magnesia, etc.), composite metal oxides (silica-alumina, titania-silica, silica-magnesia, etc.), zeolites (ZSM-5, etc.), mesoporous silicates (MCM-41, etc.), natural minerals (clay,
Diatomaceous earth, pumice, etc.).

In the present invention, Mg, Ca, Sr, Ba, A
1, Si, Ti, V, Cr, Mn, Fe, Co, Ni,
An inorganic oxide carrier composed of an oxide containing at least one element of Cu, Zn, Zr, Nb, Sn, Pb, La and Ce can be preferably used. The oxide may be a mixed oxide in which two or more elemental oxides are mixed, or may be a composite oxide (or a composite oxide).

In the present invention, as the inorganic oxide carrier, M
g, Ca, Sr, Ba, Al, Ti, V, Cr, Mn,
Fe, Co, Ni, Cu, Zn, Zr, Nb, Sn, P
An oxide containing at least one of b, La, and Ce and Si can be preferably used.

The method for producing the inorganic oxide carrier is not limited, either.
A known manufacturing method can be used. For example, an impregnation method, a coprecipitation method, an ion exchange method, a vapor deposition method, a kneading method, a hydrothermal synthesis method and the like can be mentioned.

For example, such an inorganic oxide carrier is prepared by using M
g, Ca, Sr, Ba, Al, Ti, V, Cr, Mn,
Fe, Co, Ni, Cu, Zn, Zr, Nb, Sn, P
It is obtained by impregnating silica with an aqueous solution of a water-soluble compound containing at least one of b, La and Ce, and then calcining the obtained impregnated body. Such an inorganic oxide carrier can more reliably support ultrafine gold particles as a catalytically active component, and can obtain higher catalytic activity by synergistic action with the ultrafine gold particles.

The compound used in the above production method is not limited. Examples include inorganic compounds such as nitrates, sulfates, and hydroxides, and organic compounds such as carboxylate, alkoxide, and acetylacetonate.

The water-soluble compound is not limited as long as it is water-soluble. Examples thereof include inorganic acid salts such as zinc nitrate, lanthanum nitrate, iron nitrate, nickel nitrate, and aluminum nitrate; and organic acid salts such as lead acetate and magnesium acetate. These salts may be either anhydrous or hydrated. The concentration of the aqueous solution can be appropriately set according to the type of the water-soluble compound used.

The amount of the aqueous solution to be impregnated into silica is not limited, but is usually 1 to 100 parts by weight of silica.
What is necessary is just to make it about 20 weight part.

In the present invention, the inorganic oxide carrier is preferably porous, and more preferably has a specific surface area (BET method) of usually at least 50 m ² / g, particularly preferably at least 100 m ² / g. The shape and size of the carrier are not limited,
What is necessary is just to determine suitably according to the use etc. of a final product.

The loading amount of the ultrafine gold particles in the catalyst of the present invention may be appropriately determined according to the use of the final product, the type of the carrier, and the like. It is preferably about 20 parts by weight, particularly 0.1 to 10 parts by weight.

The method for producing the catalyst of the present invention is not limited as long as it can support predetermined ultrafine gold particles. As the loading method itself, for example, a known method such as a coprecipitation method, a precipitation / precipitation method, an impregnation method, or a vapor deposition method can be used. In the present invention, a coprecipitation method, a precipitation precipitation method, or the like can be suitably used as a supporting method, and a precipitation precipitation method is more preferable. When the catalyst of the present invention is produced using the precipitation method, for example, after mixing an aqueous solution of a water-soluble compound containing gold and an inorganic oxide carrier, the catalyst of the present invention is obtained by calcining the recovered solid. Can be.

The water-soluble compound containing gold is not limited as long as it is water-soluble. For example, tetrachloroaurate (III) acid “H [AuCl ₄ ]”, sodium tetrachloroaurate (III) sodium “Na [AuCl ₄ ]”, potassium dicyanoaurate (I) potassium “K [Au (CN) ₂ ]” , Diethylamine gold (III)
Complexes such as trichloride "(C ₂ H ₅ ) ₂ NH [AuCl ₃ ]";
Gold compounds such as gold (I) cyanide; At least one of these compounds can be used.

The gold concentration of the above aqueous solution varies depending on the kind of the compound to be used and the like.
/ L. Further, the pH of the aqueous solution may be set usually in the range of about 5 to 10, preferably in the range of 6 to 9. The pH can be adjusted with an alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and ammonia. If necessary, an acid such as hydrochloric acid can be used. These alkalis or acids may be used in the form of an aqueous solution, if necessary.

If necessary, a surfactant may be added to the aqueous solution. The surfactant may be appropriately selected from known ones or commercially available ones according to the aqueous solution.
For example, anionic surfactants such as long-chain alkylsulfonic acids and salts thereof, long-chain alkylbenzenesulfonic acids and salts thereof, long-chain alkylcarboxylic acids and salts thereof, and arylcarboxylic acids and salts thereof; long-chain alkyl quaternary ammonium salts And the like; nonionic surfactants such as polyalkylene glycol and polyoxyethylene nonylphenol; and the like. At least one of these surfactants can be used. In the present invention, an anionic surfactant and a nonionic surfactant are preferred, and an anionic surfactant is particularly preferred. Among the anionic surfactants, among others, long-chain alkylsulfonic acids having 8 or more carbon atoms and salts thereof, long-chain alkylbenzenesulfonic acids having 8 or more carbon atoms and salts thereof, and long-chain alkylcarboxylic acids having 8 or more carbon atoms and the same Salts, aryl carboxylic acids and salts thereof are more preferred.

The amount of the surfactant to be used can be appropriately determined depending on the desired dispersibility, the type of the surfactant to be used, and the like. Usually, the concentration of the surfactant is 0.1 to 10 mmol.
/ L.

The inorganic oxide carrier mixed with the above aqueous solution is
Any form such as granules and granules may be used. The amount of the carrier to be used may be appropriately set according to the concentration of the aqueous solution, the type of the carrier used, and the like. When mixing the aqueous solution and the inorganic oxide carrier, the aqueous solution may be heated as necessary. The temperature in this case is usually 10 to 10
The temperature may be set to about 0 ° C.

Subsequently, after mixing the inorganic oxide carrier and an aqueous solution of a water-soluble compound containing gold, a solid content is recovered. The method for recovering the solid content is not limited. For example, the method can be performed by collecting the supernatant, or can be performed according to a known solid-liquid separation method. The recovered solid is preferably washed with ion-exchanged water or the like until the residual ions are substantially eliminated.

Next, the solid content (gold immobilized material) is fired. If necessary, it may be heated to a predetermined temperature and dried before firing. The drying temperature may be usually lower than 150 ° C. The firing temperature is usually about 150 to 800 ° C., preferably 200 to 700 ° C., and most preferably 25 to 800 ° C.
The temperature may be set to 0 to 600 ° C. What is necessary is just to set suitably so that predetermined ultrafine gold particles may be obtained within this temperature range. The firing atmosphere may be air (atmosphere) or an oxidizing atmosphere, or may be any of an inert gas atmosphere such as argon gas and helium and a reducing atmosphere such as hydrogen gas. The firing time may be appropriately determined according to the firing temperature, the size of the solid content, and the like. By such calcination, the catalyst of the present invention can be obtained.

The catalyst of the present invention can be used in a reaction for synthesizing a carboxylic acid ester by reacting an aldehyde with an alcohol in the presence of oxygen. For example,
It can be suitably used when synthesizing methyl methacrylate by reacting methacrolein with methanol, or when synthesizing methyl glyoxylate by reacting glyoxal with methanol.

Particularly, in the case of a catalyst in which ultrafine gold particles are supported on a silica carrier or a carrier containing silica, the surface of the catalyst may be subjected to an organic silylation treatment. By such treatment, it is possible to improve the catalyst performance, the life stability, and the like.
A known method can be applied to the organic silylation treatment itself, and the treatment may be performed by a gas phase method or a liquid phase method using a silylating agent such as methoxytrimethylsilane, trimethylsilyl chloride, hexamethyldisilazane, or the like. 2. Method for Producing Carboxylic Ester The method for producing carboxylic acid ester of the present invention is characterized by reacting an aldehyde with an alcohol in the presence of the catalyst of the present invention and oxygen.

Examples of the aldehyde include formaldehyde, acetaldehyde, propionaldehyde,
Aliphatic aldehydes having 1 to 10 carbon atoms such as isobutyraldehyde, glyoxal, and pyrvalaldehyde; 3 carbon atoms such as acrolein, methacrolein, and crotonaldehyde
Α, β-unsaturated aldehyde of from 10 to 10; benzaldehyde, glyoxal, p-methoxybenzaldehyde,
6-20 carbon atoms such as tolualdehyde and phthalaldehyde
And the derivatives of these aldehydes. Preferably, an aliphatic aldehyde, α,
β-unsaturated aldehydes and the like can be used. These aldehydes can be used alone or in combination of two or more.

Examples of the alcohol include aliphatic alcohols having 1 to 10 carbon atoms such as methanol, ethanol, isopropanol and octanol; diols having 2 to 10 carbon atoms such as ethylene glycol and butanediol; allyl alcohol and methallyl alcohol. Aliphatic unsaturated alcohols having 3 to 10 carbon atoms; aromatic alcohols such as benzyl alcohol; Preferably, it has 1 to 1 carbon atoms.
0 aliphatic alcohols and the like can be used. One or more of these alcohols can be used.

In the production method of the present invention, the above aldehyde and alcohol may be appropriately selected depending on the kind of the target carboxylic acid ester and the like. For example, when synthesizing methyl methacrylate, methacrolein may be used as the aldehyde and methanol may be used as the alcohol.

The reaction ratio between the aldehyde and the alcohol is not particularly limited, but the molar ratio of aldehyde / alcohol is preferably about 10 to 1/200, particularly preferably 1/2 to 1/5.
A range of 0 is more preferred. Within the above range, it becomes possible to synthesize the carboxylic acid ester more efficiently.

In the present invention, the reaction between the aldehyde and the alcohol is carried out using a catalyst comprising the composition of the present invention and oxygen (molecular oxygen).
Perform in the presence of

The above reaction may be any of a liquid phase reaction, a gas phase reaction and the like. Oxygen (oxygen gas) may be diluted with an inert gas such as a nitrogen gas, an argon gas, a helium gas, or a carbon dioxide gas. Air can also be used as oxygen. The method for supplying oxygen to the reaction system is not particularly limited, and a known method can be applied.

The form of the above reaction may be any of a continuous system, a batch system, a semi-batch system and the like, and is not particularly limited. In the case of employing a batch system as the reaction mode, the catalyst may be charged together with the raw materials into the reactor. When a continuous reaction system is employed, the reaction device may be charged with the catalyst in advance, or the catalyst may be continuously charged together with the raw material in the reaction device. The catalyst may be in any form such as a fixed bed, a fluidized bed and a suspension bed.

The amount of the catalyst used may be appropriately determined according to the combination of the aldehyde and the alcohol, the type (composition, etc.) of the catalyst, the reaction conditions and the like. The reaction time is not particularly limited, and varies depending on the set conditions. However, usually, the reaction time or the residence time (the amount of liquid retained in the reactor / the amount of liquid supplied) may be about 0.5 to 20 hours.

The conditions such as the reaction temperature and the reaction pressure may be appropriately determined according to the combination of the aldehyde and the alcohol, the type of the catalyst, and the like. The reaction temperature is usually about 0 to 180 ° C, preferably 20 to 150 ° C. By setting the temperature within this range, the reaction can proceed more efficiently. The reaction pressure may be any of reduced pressure, normal pressure or increased pressure, but is usually 0.5 to 20.
It is preferably within the range of kg / cm ² (gauge pressure). The pH of the reaction system is adjusted to pH 6 from the viewpoint of suppressing by-products.
It is desirably about 9 to about 9. For adjusting the pH, for example, an alkali metal compound or an alkaline earth metal compound (carboxylate) can also be used as an additive to the reaction system.

After the above-mentioned reaction, the catalyst may be separated from the reaction system, and the produced carboxylic acid ester may be recovered using a known separation and purification means. The catalyst may be separated according to a known method. For example, when the reaction system comprises a catalyst (solid content) and a reaction product (liquid component), the catalyst and the reaction product can be separated by a known solid-liquid separation method such as filtration and centrifugation.

The carboxylate obtained by the production method of the present invention can be used for the same applications as the carboxylate obtained by the prior art. For example, carboxylic acid esters such as acrylic acid esters and methacrylic acid esters are useful as polymerization monomers used as raw materials for various acrylic resins.

[0053]

The catalyst of the present invention exhibits excellent catalytic activity as a catalyst for synthesizing a carboxylate ester by a specific method, in particular, since ultrafine gold particles are supported on an inorganic oxide carrier. can do. Moreover, even when used repeatedly, the performance is not easily deteriorated as in the prior art, and relatively high activity can be maintained.

Among them, the inorganic oxide carrier is made of Mg, C
a, Sr, Ba, Al, Si, Ti, V, Cr, Mn,
Fe, Co, Ni, Cu, Zn, Zr, Nb, Sn, P
A catalyst for synthesizing a carboxylic acid ester comprising an oxide containing at least one element of b, La and Ce is preferred. For example, Mg, Ca, Sr, Ba, Al, Ti, V, C
r, Mn, Fe, Co, Ni, Cu, Zn, Zr, N
When using an inorganic oxide carrier obtained by impregnating silica with an aqueous solution of a water-soluble compound containing at least one of b, Sn, La and Ce, and then calcining the obtained impregnated body, it is preferable to use a super-gold alloy. The fine particles can be supported more reliably, and further excellent catalytic activity can be exhibited by the synergistic action of the ultrafine gold particles and the inorganic oxide carrier.

[0055]

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention. However, the scope of the present invention is not limited to the scope of the examples.

The conversion rates in the examples and comparative examples were as follows:
The selectivity and the yield were calculated based on the following equations.

Conversion (%) = (1-B / A) × 100 Selectivity (%) = {C / (AB)} × 100 Yield (%) = (C / A) × 100 In the above three formulas, A: the number of moles of the charged aldehyde, B: the number of moles of the remaining aldehyde, and C: the number of moles of the generated carboxylic acid ester.) Example 1 (1) Preparation of Catalyst Concentration: 10 mmol / L 500 ml of chloroauric acid aqueous solution
While maintaining the temperature at 5 to 70 ° C, the pH was adjusted to 7 using a 0.5N aqueous sodium hydroxide solution. Commercially available γ
-Alumina (product name "AC-12R" manufactured by Sumitomo Chemical) 40
g was added under stirring, and stirring was continued for 1 hour while maintaining the temperature at 65 to 70 ° C. Thereafter, the washing step of removing the supernatant liquid by allowing it to stand still, adding 0.8 L of ion-exchanged water to the remaining gold-immobilized substance, stirring at room temperature for 5 minutes, and removing the supernatant liquid was repeated three times. . The immobilized gold obtained by filtration was
The resultant was dried at 00 ° C. for 10 hours and further calcined in air at 300 ° C. for 3 hours to obtain a gold carrier (Au / γ-alumina) in which gold was supported on an alumina carrier.

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.6% by weight based on the carrier. Further, the state analysis of the gold particles of the carrier was examined by a transmission electron microscope (TEM) (device name "HF-2000" Hitachi, accelerating voltage 200 kV) (the same applies hereinafter). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle size of 5 nm or less, showed a narrow particle size distribution having a maximum around a particle size of 2 to 3 nm, and an average particle size of 5 nm or less. (2) Synthesis of carboxylic acid ester Gold carrier (Au / γ-alumina) obtained in (1) above
Was used to synthesize a carboxylic acid ester.

1.5 ml of methacrolein, 15 ml of methanol and 0.5 g of the above-mentioned gold carrier were placed in a 100 ml autoclave with rotary stirring and sealed. Next, after the inside of the system was pressurized to ² kg / cm ² with oxygen, the system was heated to 80 ° C. with stirring and maintained at this temperature for 2 hours. Then cool down,
The package was opened, the catalyst and the reaction solution were separated by filtration, and the reaction solution was analyzed by gas chromatography. As a result, the conversion of methacrolein was 88%, the selectivity and yield of methyl methacrylate were 85% and 75%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 13.6 mol.
1 / h / kg-catalyst.

Example 2 A gold carrier (Au / γ-alumina) was prepared in the same manner as in Example 1, except that the firing temperature of the gold-immobilized product was 400 ° C.
Was manufactured.

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.6% by weight based on the carrier. Further, the state analysis of the gold particles of the carrier was examined by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle size of 5 nm or less, showed a narrow particle size distribution having a maximum around a particle size of 2 to 3 nm, and an average particle size of 5 nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 1 using this gold carrier (Au / γ-alumina). The produced reaction solution was analyzed by gas chromatography in the same manner as in Example 1. As a result, the conversion of methacrolein was 85%, the selectivity and yield of methyl methacrylate were 84% and 71%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 13.0 mol / h.
/ Kg-catalyst.

Example 3 A gold-supported material (Au / γ-alumina) was prepared in the same manner as in Example 1 except that the firing temperature of the gold-immobilized product was 600 ° C.
Was manufactured.

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.6% by weight based on the carrier. Further, the state analysis of the gold particles of the carrier was examined by a transmission electron microscope (TEM). As a result, most of the gold was highly dispersed with a particle diameter of 3 to 6 nm, and the average particle diameter was 6 nm.
nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 1 using this gold carrier (Au / γ-alumina). The produced reaction solution was analyzed by gas chromatography in the same manner as in Example 1. As a result, the conversion of methacrolein was 51%, the selectivity and the yield of methyl methacrylate were 72% and 37%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 6.7 mol / h / h.
kg-catalyst.

Comparative Example 1 A gold carrier (Au / γ-alumina) was prepared in the same manner as in Example 1, except that the firing temperature of the gold-immobilized product was 700 ° C.
Was manufactured.

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.6% by weight based on the carrier. Further, the state analysis of the gold particles of the carrier was examined by a transmission electron microscope (TEM). As a result, it was confirmed that most of the gold had a particle diameter exceeding 6 nm, and the average particle diameter exceeded 6 nm.

A carboxylic acid ester was synthesized in the same manner as in Example 1 using this gold support (Au / γ-alumina). The produced reaction solution was analyzed by gas chromatography in the same manner as in Example 1. As a result, the conversion of methacrolein was 27%, the selectivity and yield of methyl methacrylate were 52% and 14%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 2.5 mol / h / h.
kg-catalyst. From these results, it was confirmed that when the average particle size exceeded 6 nm, the catalytic activity was inferior to Examples 1 to 3.

Comparative Example 2 A gold carrier (Au / γ-alumina) was prepared in the same manner as in Example 1, except that the firing temperature of the gold-immobilized product was 800 ° C.
Was manufactured.

The amount of gold carried on this carrier was measured by X-ray fluorescence analysis and found to be 4.6% by weight based on the carrier. Further, the state analysis of the gold particles of the carrier was examined by a transmission electron microscope (TEM). As a result, almost all of the gold has a particle size exceeding 6 nm and the average particle size is 6 nm.
It was confirmed that it exceeded nm.

Using this gold carrier (Au / γ-alumina), a carboxylic acid ester was synthesized in the same manner as in Example 1. The produced reaction solution was analyzed by gas chromatography in the same manner as in Example 1. As a result, the conversion of methacrolein was 18%, the selectivity and yield of methyl methacrylate were 42% and 8%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 1.4 mol / h / k.
g-catalyst.

Example 4 (1) Preparation of Catalyst Preparation of Silica Carrier Aqueous solution 25 containing 7.03 g of aluminum nitrate 9 hydrate
10 g of a commercially available silica carrier (product name "Caractact Q-10" manufactured by Fuji Silysia Chemical Ltd.) was added to each ml, and the aqueous solution was impregnated into the silica carrier. Next, the silica carrier impregnated with the above solution was dried at 120 ° C for 12 hours, and then calcined in air at 600 ° C for 4 hours. As a result, an Al-silica support containing aluminum in silica was obtained.

Au loading While maintaining 250 ml of an aqueous solution of chloroauric acid having a concentration of 10 mmol / L at 65 to 70 ° C, the pH was adjusted to 7 using a 0.5N aqueous sodium hydroxide solution. 10 g of the above-mentioned Al-silica carrier was added to this aqueous solution with stirring, and 65 to 70
Stirring was continued for 1 hour while maintaining the temperature at ° C. Thereafter, the washing step of removing the supernatant liquid by allowing it to stand still, adding 0.8 L of ion-exchanged water to the remaining gold-immobilized substance, stirring at room temperature for 5 minutes, and removing the supernatant liquid was repeated three times. . The gold-immobilized product obtained by filtration was dried at 100 ° C. for 10 hours, and further calcined in air at 400 ° C. for 3 hours to obtain an Al—
A gold carrier having gold supported on a silica carrier (Au / Al /
Silica).

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.5% by weight based on the carrier. Further, the Al content was 4.5% by weight in the carrier. In addition, the state of the metal species of the support was analyzed by a transmission electron microscope (TEM). As a result, almost all of the gold was highly dispersed with a particle size of 5 nm or less, and a particle size of 2
It showed a narrow particle size distribution having a maximum around ｎｍ3 nm, and it was confirmed that the average particle size was 5 nm or less. (2) Synthesis of carboxylic acid ester Gold carrier (Au / Al / silica) obtained in (1) above
Was used to synthesize a carboxylic acid ester.

A 100 ml autoclave equipped with rotary stirring was charged with 1.5 ml of methacrolein, 15 ml of methanol and 0.5 g of the above-mentioned gold-supported material (Au / Al / silica) and sealed. Next, after the inside of the system was pressurized to ² kg / cm ² with oxygen, the system was heated to 80 ° C. with stirring and maintained at this temperature for 2 hours. Then, it cooled, opened, separated the catalyst and the reaction liquid by filtration, and analyzed the reaction liquid by gas chromatography. As a result, the conversion of methacrolein was 75%, the selectivity and yield of methyl methacrylate were 88% and 66%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 12.0 mol / h / kg-catalyst.

Example 5 A Ti-silica carrier was prepared in the same manner as in Example 4 except that a methanol solution containing 3.55 g of titanium tetra-n-butoxide was used instead of the aqueous solution containing 7.03 g of aluminum nitrate nonahydrate. Carrying gold (Au / T)
i / silica).

The amount of gold carried on the carrier was measured by fluorescent X-ray analysis, and was found to be 4.8% by weight based on the carrier. Further, the Ti content was 4.9% by weight in the carrier. In addition, the state of the metal species of the support was analyzed by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 4 using the above-mentioned gold support (Au / Ti / silica). As a result, the conversion of methacrolein was 71%, and the selectivity and yield of methyl methacrylate were 87%, respectively.
And 62%, the activity of forming methyl methacrylate per unit catalyst weight was 11.2 mol / h / kg-catalyst.

Example 6 Gold was supported on a Zn-silica carrier in the same manner as in Example 4, except that 2.28 g of zinc nitrate hexahydrate was used instead of 7.03 g of aluminum nitrate 9-hydrate. Gold carrier (A
u / Zn / silica).

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.5% by weight based on the carrier. Further, the Zn content was 5.0% by weight in the carrier. In addition, the state of the metal species of the support was analyzed by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 4 using the above-described gold support (Au / Zn / silica). As a result, the conversion of methacrolein was 97%, and the selectivity and yield of methyl methacrylate were 91%, respectively.
And 88%, the activity of forming methyl methacrylate per unit catalyst weight was 16.0 mol / h / kg-catalyst.

Example 7 Lanthanum nitrate 6 instead of 2.28 g of zinc nitrate hexahydrate
Except for using 1.56 g of hydrate, a gold-supported material (Au /
La / silica).

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.8% by weight based on the carrier. Further, the La content was 5.0% by weight in the carrier. In addition, the state of the metal species of the carrier was analyzed by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 4 using the above-mentioned gold support (Au / La / silica). As a result, the conversion of methacrolein was 99% and the selectivity and yield of methyl methacrylate were 92%, respectively.
And 91%, the activity of forming methyl methacrylate per unit catalyst weight was 16.5 mol / h / kg-catalyst.

Example 8 Gold was carried on a Ce-silica carrier in the same manner as in Example 1, except that 1.49 g of cerium nitrate pentahydrate was used instead of 7.03 g of aluminum nitrate nonahydrate. A gold carrier (Au / Ce / silica) was obtained.

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis, and was found to be 4.8% by weight based on the carrier. Further, the Ce content was 4.9% by weight in the carrier. In addition, the state of the metal species of the support was analyzed by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 4 using the above-described gold support (Au / Ce / silica). As a result, the conversion of methacrolein was 64%, and the selectivity and yield of methyl methacrylate were 87%, respectively.
And the activity of forming methyl methacrylate per unit catalyst weight was 10.1 mol / h / kg-catalyst.

Example 9 0.92 g of lead acetate trihydrate and magnesium acetate tetrahydrate were used instead of 7.03 g of aluminum nitrate nonahydrate.
Pb-M was prepared in the same manner as in Example 4 except that 76 g was used.
g / silica carrier with gold supported (Au / Pb
-Mg / silica).

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.8% by weight based on the carrier. The contents of Pb and Mg in the carrier were 5.0% by weight and 2.0% by weight, respectively. In addition, the state analysis of the metal species of the carrier was performed by a transmission electron microscope (TEM).
I checked in. As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less.

Using the above-mentioned gold support (Au / Pb-Mg / silica), a carboxylic acid ester was synthesized in the same manner as in Example 4. As a result, the conversion of methacrolein was 8
The selectivity and yield of methyl methacrylate were 3%, 92% and 81%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 13.9 mol / h / kg-catalyst.

Example 10 The procedure of Example 7 was repeated, except that the lanthanum nitrate hexahydrate was changed from 1.56 g to 3.12 g and the amount of La-silica used was changed from 10 g to 5 g. Supported on a La-silica carrier (Au /
La / silica).

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 8.4% by weight based on the carrier. Further, the La content was 10.1% by weight in the carrier. In addition, the state of the metal species of the support was analyzed by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 4 except that the above gold-supported material (Au / La / silica) was used and the oxygen pressure in the system was set to 3 kg / cm ² and the reaction time was set to 1 hour. As a result, the conversion of methacrolein is 98%,
The selectivity and yield of methyl methacrylate were 93
% And 91%, the activity of forming methyl methacrylate per unit catalyst weight was 33.0 mol / h / kg-catalyst.

Example 11 Using the catalyst obtained in Example 10, methacrolein
Example 1 except that 0 ml and methanol 12 ml were used.
Synthesis of carboxylic acid ester was carried out in the same manner as in Example 1.
As a result, the conversion of methacrolein was 78%, and the selectivity and yield of methyl methacrylate were 89% and 69%, respectively.
%, The activity of forming methyl methacrylate per unit catalyst weight was 50.4 mol / h / kg-catalyst.

Example 12 Using the catalyst obtained in Example 10, methacrolein
Example 1 except that 0 ml and methanol 12 ml were used.
Synthesis of carboxylic acid ester was carried out in the same manner as in Example 1.
As a result, the conversion of methacrolein was 54%, the selectivity and the yield of methyl methacrylate were 86% and 46%, respectively.
%, The activity of forming methyl methacrylate per unit catalyst weight was 45.0 mol / h / kg-catalyst.

Example 13 Using the catalyst obtained in Example 10, a carboxylic acid ester was synthesized. 1.5 ml of acrolein, 15 ml of methanol and 0.5 g of the above gold-supported material (Au / La / silica) were placed in a 100 ml autoclave with rotary stirring, and sealed. Next, after the inside of the system was pressurized to 3 kg / cm ² with oxygen, the system was heated to 70 ° C. with stirring and maintained at this temperature for 3 hours. Then, it cooled, opened, separated the catalyst and the reaction liquid by filtration, and analyzed the reaction liquid by gas chromatography. As a result, the conversion of acrolein was 95%, and the selectivity and yield of methyl acrylate were 84% and 80%, respectively.

Example 14 A carboxylic acid ester was synthesized using the catalyst obtained in Example 10. 2 g of 40% aqueous glyoxal solution and 15 g of methanol
ml and 0.5 g of the gold carrier (Au / La / silica)
And sealed. Next, the inside of the system was oxygenated at 3 kg / c.
After pressurizing to m ² , the mixture was heated to 80 ° C. with stirring, and this temperature was maintained for 1 hour. Thereafter, the mixture was cooled, opened, the catalyst and the reaction solution were separated by filtration, and the reaction solution was analyzed by liquid chromatography and gas chromatography. As a result, the conversion of glyoxal was 53%, and the selectivity and yield of methyl glyoxylate were 87% and 46%, respectively.

Example 15 The catalyst obtained in Example 10 was replaced with glass U having an inner diameter of 10 mm.
A helium gas containing about 8% by volume of methoxytrimethylsilane was flowed at a flow rate of 6 L / hour for 10 minutes while the catalyst layer was heated to 280 ° C. Using 0.5 g of the silylation catalyst thus obtained, a reaction was carried out in the same manner as in Example 14. The obtained reaction solution was analyzed by liquid chromatography and gas chromatography in the same manner as in Example 10. As a result, the conversion of glyoxal was 75%, and the selectivity and yield of methyl glyoxylate were 82% and 62%, respectively.

Example 16 Using the catalyst obtained in Example 10, a carboxylic acid ester was synthesized. 2 g of propionaldehyde, 15 ml of ethanol and 0.5 g of the above-mentioned gold-supported material (Au / La / silica) were placed in a 100 ml autoclave with rotary stirring and sealed. Next, after pressurizing the inside of the system to 3 kg / cm ² with oxygen, the system was heated to 80 ° C. with stirring and maintained at this temperature for 2 hours. Thereafter, the reaction solution was cooled, opened, the catalyst and the reaction solution were separated by filtration, and the reaction solution was analyzed by gas chromatography. As a result, the conversion of propionaldehyde was 8
The selectivity and yield of 3%, ethyl propionate were 90% and 75%, respectively.

Example 17 Using the catalyst obtained in Example 10, a carboxylic acid ester was synthesized. 2 g of isobutyraldehyde, 15 ml of ethanol and 0.5 g of the above-mentioned gold-supported material (Au / La / silica) were placed in a 100 ml autoclave with rotary stirring and sealed. Next, the inside of the system was pressurized to 3 kg / cm ² with oxygen, heated to 65 ° C. with stirring, and maintained at this temperature for 2 hours. Then, it cooled, opened, separated the catalyst and the reaction liquid by filtration, and analyzed the reaction liquid by gas chromatography. As a result, the conversion of isobutyraldehyde was 8
0%, selectivity and yield of ethyl isobutyrate were 88
% And 70%.

Example 18 A carboxylic acid ester was synthesized using the catalyst obtained in Example 10. 2 g of benzaldehyde and 15 ml of 1-propanol in an autoclave with 100 ml rotation and stirring.
And 0.5 g of the above-mentioned gold carrier (Au / La / silica) was put therein and sealed. Next, the inside of the system was oxygenated with 3 kg / cm ^2.
Then, the mixture was heated to 70 ° C. with stirring, and this temperature was maintained for 4 hours. Then, it cooled, opened, separated the catalyst and the reaction liquid by filtration, and analyzed the reaction liquid by gas chromatography. As a result, the conversion of benzaldehyde was 89.
%, Propyl benzoate selectivity and yield are 88
% And 70%.

Example 19 (1) Preparation of Catalyst 500 ml of an aqueous solution of chloroauric acid having a concentration of 10 mmol / L was added to 6
While maintaining the temperature at 5 to 70 ° C., the aqueous solution was adjusted to pH 7 using a 0.5N aqueous sodium hydroxide solution. Commercially available titania (anatase type, manufactured by Norton) 1
0 g was added under stirring, and stirring was continued for 1 hour while maintaining the temperature at 65 to 70 ° C. and the pH at 7 to 8. Thereafter, the supernatant was removed by standing still, and 0.8 g of ion-exchanged water was added to the remaining immobilized gold.
After adding L and stirring at room temperature for 5 minutes, the washing step of removing the supernatant was repeated three times. The gold-immobilized product obtained by filtration was dried at 100 ° C. for 10 hours, and further calcined in air at 400 ° C. for 3 hours to obtain a gold-supported material (Au / titania) in which gold was supported on a titania carrier. .

The amount of gold carried on the carrier was measured by X-ray fluorescence analysis and found to be 4.7% by weight based on the carrier. Further, the state analysis of the gold particles of the carrier was examined by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less. (2) Synthesis of carboxylic acid ester A carboxylic acid ester was synthesized using the gold-supported substance (Au / titania) obtained in the above (1).

1.5 ml of methacrolein, 15 ml of methanol and 0.5 g of the above-mentioned gold carrier were placed in a 100 ml autoclave with rotary stirring, and sealed. Next, after the inside of the system was pressurized to ² kg / cm ² with oxygen, the system was heated to 80 ° C. with stirring and maintained at this temperature for 2 hours. Then cool down,
The package was opened, the catalyst and the reaction solution were separated by filtration, and the reaction solution was analyzed by gas chromatography. As a result, the conversion of methacrolein was 83%, the selectivity and yield of methyl methacrylate were 81% and 67%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 12.2 mol.
1 / h / kg-catalyst.

Example 20 A gold carrier (Au) in which gold was carried on a zirconia carrier in the same manner as in Example 19, except that a commercially available zirconia (manufactured by Norton) was used instead of titania as the carrier. / Zirconia).

The amount of gold carried on this carrier was measured by X-ray fluorescence analysis and found to be 4.4% by weight based on the carrier. In addition, the state of the metal species of the support was analyzed by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 19 using the above-described gold-supported material (Au / zirconia). The obtained reaction solution was analyzed by gas chromatography in the same manner as in Example 19. As a result, the conversion of methacrolein was 69%, the selectivity and the yield of methyl methacrylate were 83% and 53%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 9.6 mol / h.
/ Kg-catalyst.

Example 21 (1) Preparation of catalyst 40.4 g of iron nitrate 9 hydrate and 0.8 of chloroauric acid tetrahydrate
500 ml of an aqueous solution containing 8 g and heated to 70 ° C.
Containing 19.6 g of sodium carbonate at 65-70 ° C.
The whole amount was poured over about 1 minute into 500 ml of the heated aqueous solution with stirring. Thereafter, stirring was continued while maintaining the temperature at 65 to 70 ° C., and the supernatant was removed by centrifugation. 1
L for 30 minutes each for 10 minutes
After repeating the process twice, the obtained solid was dried at 120 ° C. for 12 hours, and further calcined in air at 450 ° C. for 4 hours to obtain a gold carrier (Au / Fe) in which gold was supported on iron oxide.
₂ O ₃ ) was obtained.

The amount of gold carried on the carrier was measured by fluorescent X-ray analysis, and was found to be 4.8% by weight based on the carrier. Further, the state analysis of the gold particles of the carrier was examined by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less. (2) Synthesis of carboxylate ester A carboxylate ester was synthesized using the gold support (Au / Fe ₂ O ₃ ) obtained in the above (1).

In a 100 ml autoclave with rotary stirring, 1.5 ml of methacrolein, 15 ml of methanol and 0.5 g of the above-mentioned gold carrier were sealed and sealed. Next, after the inside of the system was pressurized to ² kg / cm ² with oxygen, the system was heated to 80 ° C. with stirring and maintained at this temperature for 2 hours. Then cool down,
The package was opened, the catalyst and the reaction solution were separated by filtration, and the reaction solution was analyzed by gas chromatography. As a result, the conversion of methacrolein was 66%, the selectivity and yield of methyl methacrylate were 87% and 57%, respectively, and the activity of forming methyl methacrylate per unit catalyst weight was 10.3 mol.
1 / h / kg-catalyst.

Example 22 In Example 21, 29.8 g of zinc nitrate hexahydrate was used instead of 40.4 g of iron nitrate nonahydrate, and 0.81 g of chloroauric acid tetrahydrate was changed to 0.51 g. And sodium carbonate 1
Except that 9.6 g was changed to 13.2 g, a gold carrier (Au / Z) in which gold was supported on zinc oxide in the same manner as in Example 21.
nO).

The amount of gold carried on this carrier was measured by X-ray fluorescence analysis and found to be 2.9% by weight based on the carrier. In addition, the state of the metal species of the support was analyzed by a transmission electron microscope (TEM). As a result, it was confirmed that almost all of the gold was highly dispersed with a particle diameter of 5 nm or less, and the average particle diameter was 5 nm or less.

A carboxylic acid ester was synthesized in the same manner as in Example 21 using the above gold-supported material. The obtained reaction solution was analyzed by gas chromatography in the same manner as in Example 21. As a result, the conversion of methacrolein was 74%,
The selectivity and yield of methyl methacrylate are 81
% And 60%, the activity of forming methyl methacrylate per unit catalyst weight was 10.9 mol / h / kg-catalyst.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07C 69/54 C07C 69/54 Z 69/67 69/67 69/78 69/78 // C07B 61/00 300 C07B 61/00 300 F term (for reference) 4G069 AA03 AA08 BA01B BA02B BA03B BA04B BA05B BB04B BB06B BC10B BC21B BC33A BC33B BC35B BC42B BC43B BC66B CB75 DA05 EA01X EA02X EB18B10 BA18 FAB18A18B18B18B18B19B18B18B18B18B19B18 CF30

Claims (5)

[Claims] 1. A catalyst for use in a reaction for synthesizing a carboxylic acid ester by reacting an aldehyde with an alcohol in the presence of oxygen, wherein ultrafine gold particles having an average particle diameter of 6 nm or less are supported on an inorganic oxide carrier. A catalyst for synthesizing a carboxylic acid ester, which is characterized in that: 2. An inorganic oxide carrier comprising Mg, Ca, Sr, B
a, Al, Si, Ti, V, Cr, Mn, Fe, Co,
The carboxylic acid ester synthesis catalyst according to claim 1, comprising an oxide containing at least one element of Ni, Cu, Zn, Zr, Nb, Sn, Pb, La, and Ce. 3. An inorganic oxide carrier comprising Mg, Ca, Sr, B
a, Al, Ti, V, Cr, Mn, Fe, Co, Ni,
2. An oxide containing at least one of Cu, Zn, Zr, Nb, Sn, Pb, La and Ce and Si.
The catalyst for synthesizing a carboxylic acid ester according to the above. 4. The carboxylate according to claim 1, which is obtained by mixing an aqueous solution of a water-soluble compound containing gold and an inorganic oxide carrier and calcining the collected solid. Catalyst for synthesis. 5. A method for producing a carboxylic acid ester, comprising reacting an aldehyde with an alcohol in the presence of the catalyst for synthesizing a carboxylic acid ester according to claim 1 and oxygen.