KR20130129739A - Mixed oxide catalysts with ordered mesopores, method of preparing the same and method of producing ester compounds using the same - Google Patents

Abstract

The present invention provides a complex oxide catalyst having cylindrical regular mesopores and excellent acid characteristics and a manufacturing method thereof. A complex oxide catalyst according to the concrete example of the present invention includes tungsten oxide, zirconium oxide, and silicon oxide. The atomic fraction of the tungsten and the silicon is 0.1/1-0.14/1, and the atomic fraction of the zirconium and the silicon is 0.1/1-0.14/1. Moreover, the present invention provides a method for effectively manufacturing a high-value ester compound from ethanol and a carboxylic acid compound using the complex oxide catalyst. [Reference numerals] (AA) Example 1;(BB) Example 2;(CC) Example 3;(DD) Comparative example 2;(EE) Comparative example 3

Description

TECHNICAL FIELD The present invention relates to a composite oxide catalyst having a uniform mesopore, a method for producing the catalyst, and a method for producing an ester compound using the catalyst,

The present invention relates to a composite oxide catalyst having uniform mesopores, a process for producing the catalyst, and a process for producing an ester compound from an alcohol compound and a carboxylic acid compound using the catalyst. More specifically, the present invention has ordered mesopores in a cylindrical form and has excellent acid character attributed to clusters of zirconium oxide and tungsten oxide, so that a new compound An oxide catalyst and a method for effectively producing the catalyst. The present invention also provides a method for producing a high-value-added ester compound from an alcohol and a carboxylic acid compound obtained from a large amount of biomass resources using the catalyst.

Acid catalyst materials are widely used in various chemical reactions such as dehydration, isomerization, cracking, esterification, and the like. In particular, solid acid catalysts have been the subject of much research because they can solve environmental pollution caused by homogeneous catalysts such as inorganic acids (sulfuric acid, hydrochloric acid, nitric acid, etc.) and difficulties in separation process. In recent years, the importance of solid acid catalysts has increased, as efforts to utilize renewable and clean biomass resources instead of fossil resources such as petroleum and coal have increased. This is because solid acid materials can promote the conversion of high-value fuels and compounds by lowering the high O / C ratio of biomass such as hydrolysis, dehydration, and hydrogenolysis.

However, most of the solid acid catalysts studied so far have certain limitations. For example, zeolite, which is a typical solid acid catalyst, is difficult to use for the reaction of a substance having a large molecular weight such as cellulose because the pore size is very small. Sulfated zirconia catalysts, also known as super strong acids, release volatile sulfur contaminants during the reaction and have a disadvantage in that the catalytic activity is easily lowered. In addition, heteropoly acid, which is widely used for redox reaction as well as excellent acid characteristics, is easily leached from an aqueous solution.

On the other hand, tungstated zirconia (WO _x / ZrO ₂ ) catalyst has been attracting attention as a new solid acid substance after it has been found to exhibit high activity in the azeotropic reaction of alkane compounds at low temperature with strong acid strength . In particular, tungsten oxide zirconium oxide catalysts are excellent in high temperature stability and chemical stability, and efforts to utilize them in various processes are continuing. However, the conventional tungsten oxide zirconium catalyst has a disadvantage that it is difficult to form clusters of zirconium and tungsten oxide (Zr-WO _x ) exhibiting acid characteristics at a high density, and it is difficult to utilize the zirconium and tungsten oxide clusters for liquid phase reaction because of their small specific surface area.

In order to overcome the disadvantages of the prior art, the present inventors have found that by uniformly combining zirconium, tungsten and silicon oxide through sequential hydrolysis, the zirconium-tungsten oxide clusters Zr-WO _x ) and a process for preparing the same.

In addition, the present inventors have developed a new process for converting an alcohol and a carboxylic acid compound generated in a fermentation process of biomass resources into a high-value-added ester compound using the above-mentioned composite oxide catalyst.

It is an object of the present invention to provide a new composite oxide catalyst having regular mesopores, broad specific surface area and excellent acid properties.

Another object of the present invention is to provide a composite oxide catalyst having a high-density zirconium-tungsten oxide cluster.

It is still another object of the present invention to provide a method for efficiently producing the catalyst using a sequential hydrolysis reaction.

It is still another object of the present invention to provide a method for converting alcohols and carboxylic acid compounds obtained from biomass resources into high value-added ester compounds using the catalyst.

The above and other objects of the present invention can be achieved by the present invention described in detail below.

In order to achieve the above object, the present invention provides a composite oxide catalyst comprising tungsten oxide, zirconium oxide and silicon oxide, wherein the atomic ratio of tungsten / silicon is 0.1 / 1-0.14 / 1, the zirconium / The atomic ratio of silicon is 0.01 / 1 to 0.14 / 1, and the regular mesopores of the cylindrical shape are regular.

The composite oxide catalyst may have an atomic ratio of zirconium / tungsten of 0.1 / 1 to 0.9 / 1.

The composite oxide catalyst may have a specific surface area of 400 m ² / g or more, more specifically, a specific surface area of 400 to 700 m ² / g.

The average diameter of the mesopores may be between 4 and 8 nm.

The method for preparing a composite oxide catalyst according to another embodiment of the present invention comprises the steps of adding an alcohol solution containing a zirconium precursor dropwise to an acidic aqueous solution containing a surfactant and then mixing the aqueous solution in an aqueous solution containing a tungsten precursor Adding a silica precursor to the secondary mixed solution, heating the mixed solution mixed with the silica precursor to make a suspension, filtering and drying the suspension, and drying the dried product in an oxygen atmosphere Lt; / RTI >

The method for producing an ester compound according to another embodiment of the present invention comprises reacting an alcohol compound and a carboxylic acid compound in the presence of the complex oxide catalyst.

The alcohol compound may be methanol, ethanol, propanol, butanol, pentanol, or a mixture thereof.

The carboxylic acid compound may be formic acid, acetic acid, propionic acid, butanoic acid or a mixture thereof.

The complex oxide catalyst according to the embodiment of the present invention can exhibit excellent acid catalytic performance in the liquid phase reaction of biomass resources because it has a regular mesopore in the form of a cylinder and a wide specific surface area and at the same time possesses excellent acidic characteristics. The composite oxide catalyst has an advantage that it contains clusters of zirconium-tungsten oxide exhibiting acid characteristics at high density.

In addition, the composite oxide catalyst can effectively produce a high-value-added ester compound from an alcohol and a carboxylic acid compound obtained from a large amount of biomass resources.

In addition, the method for preparing a composite oxide catalyst according to another embodiment of the present invention can produce a new composite oxide catalyst having regular mesopores, wide specific surface area and excellent acid characteristics through sequential hydrolysis, to be.

1 is a transmission electron microscope photograph of the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 and 2.
2 is a graph showing the results of nitrogen adsorption / desorption analysis of the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 and 2.
3 is a graph showing X-ray diffraction patterns of the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 and 2.
4 is a graph comparing yields of butyl acetate in Examples 4 to 6 and Comparative Experiments 3 to 6.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a composite oxide catalyst having uniform mesopores according to embodiments and examples of the present invention will be described in detail with reference to the accompanying drawings, a method for producing the same, and a method for producing an ester compound using the same. However, it is to be understood that the invention is not limited to the specific embodiments described below, and that those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. It should be understood that water and variations may be present.

In addition, the terms or words used in the specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should appropriately define the concept of terms in order to explain their invention in the best way. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that it can.

Composite oxide catalysts with homogeneous mesopores

The composite oxide catalyst according to the present invention comprises tungsten oxide, zirconium oxide and silicon oxide and has regular mesopores in the form of cylinders. It is known that a tungsten oxide zirconium oxide (WO _x / ZrO ₂ ) catalyst acts as a acid point in a cluster (Zr-WO _x ) in which zirconium and tungsten oxide are organically bound. However, the conventional tungsten oxide zirconium catalyst has a low pore size and a very small specific surface area, so that the acid catalyst performance is not high and it is difficult to use in the liquid phase reaction. However, it has not been easy to form clusters of zirconium-tungsten oxide on the carrier to determine the acid characteristics (intensity and amount of acid sites) of catalysts.

The composite oxide catalyst according to the present invention uniformly combines silicon oxide, which is advantageous for making mesopores, with tungsten oxide and zirconium oxide, and thus has a uniform pore size in the form of cylinders, and at the same time a zirconium-tungsten oxide cluster having a high density.

The complex oxide catalyst preferably has an atomic ratio of tungsten (W) / silicon (Si) of 0.1 / 1 to 0.14 / 1 and an atomic ratio of zirconium (Zr) / silicon (Si) of 0.01 / Do. If the atomic ratio of tungsten / silicon is less than 0.1 / 1 and the atomic ratio of zirconium / silicon is less than 0.01 / 1, clusters of zirconium-tungsten oxide are not formed well and it is difficult to show acid characteristics. Further, when the atomic ratio of tungsten / silicon exceeds 0.14 / 1 and the atomic ratio of zirconium / silicon exceeds 0.14 / 1, it is difficult to have regular mesopores in a cylindrical shape and the specific surface area is lowered.

In one embodiment of the present invention, the composite oxide catalyst preferably has a zirconium / tungsten atomic ratio of 0.1 / 1 to 0.9 / 1 in order to further improve acid characteristics and regular pore structure.

The composite oxide catalyst has a large specific surface area. Since the catalytic action is carried out on the surface, the larger the specific surface area, the more favorable the catalytic reaction. Therefore, the upper limit value of the specific surface area is not particularly limited. In an embodiment of the present invention, the composite oxide catalyst has a specific surface area of 350 m ² / g or more, specifically 400 to 700 m ² .

In addition, since the composite oxide catalyst has a large specific pore size and a wide mesopore size, it can exhibit excellent catalytic performance even in a liquid phase reaction. In an embodiment of the present invention, the average diameter of the mesopores of the composite oxide catalyst is 3.5 nm or more, specifically 4 to 8 nm.

METHOD FOR MANUFACTURING COMPOSITE OXIDE CATALYSTS WITH MULTIPLE MIG POTS

In order to form a cluster of zirconium-tungsten oxide at a high density while making a uniform mesoporous structure, a method of preparing a composite oxide catalyst according to the present invention is a method in which a zirconium precursor, a tungsten precursor and a silica precursor are sequentially Hydrolysis and condensation reaction.

The method for preparing the composite oxide catalyst comprises the steps of: dropwise adding an alcoholic solution containing a zirconium precursor to an acidic aqueous solution containing a surfactant, and mixing the aqueous solution with the aqueous solution containing a tungsten precursor in the primary mixed solution; mixing the silica precursor with the second mixed solution, heating the mixed solution mixed with the silica precursor to make a suspension, filtering and drying the suspension, In an oxygen atmosphere.

Specifically, first, a solution in which the surfactant is dissolved in the acidic aqueous solution and a solution in which the zirconium precursor is dissolved in the alcohol are prepared. The surfactant forms a micelle through self-assembly, thereby inducing the structure of pores. The surfactant is not particularly limited as long as it can form a pore structure in the finished catalyst, in particular, a regular mesopore structure in the form of a cylinder, and any of them can be used. For example, the surfactant may be a Pluronic or Tetronic block copolymer. Specific examples of the block copolymer include F108 (EO ₁₃₂ PO ₅₀ EO ₁₃₂ , EO = ethylene oxide, PO = propylene oxide), F98 (EO ₁₂₃ PO ₄₇ EO ₁₂₃ ), F88 (EO ₁₀₃ PO ₃₉ EO ₁₀₃ ), P123 ( EO ₂₀ PO ₇₀ EO ₂₀ ), P105 (EO ₃₇ PO ₅₈ EO ₃₇ ), P104 (EO ₂₇ PO ₆₁ EO ₅₇ ) and mixtures thereof.

As the acidic aqueous solution, a mixture of inorganic acid and distilled water may be used. Specific examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and mixtures thereof. Of these, hydrochloric acid is more preferable.

Generally, a mesoporous material is produced by the hydrolysis and condensation reaction of a metal oxide precursor under the catalytic action of an acidic substance around the micelle of the surfactant and bonding each other. When the metal oxide is more strongly bonded through the heat treatment and the micelle is removed, the porosity is formed as the site where the micelle is present becomes empty. However, many precursors of transition metal oxides have a very irregular shape due to the separation of the metal oxide precursor and the micelle because the rate of hydrolysis and condensation reaction in the acidic aqueous solution is very fast, making it difficult to have a regular pore structure.

Therefore, the present inventors inhibited the abrupt reaction of the zirconium precursor by gradually adding a solution in which the zirconium precursor with high rate of hydrolysis and condensation reaction was dissolved in alcohol, by drop-wise addition and primary mixing.

The zirconium precursor may be zirconium ethoxide, zirconium butoxide, zirconium isopropoxide, or a mixture thereof. However, the zirconium precursor is not necessarily limited to zirconium ethoxide, zirconium butoxide, zirconium isopropoxide, or mixtures thereof. The kind of the alcohol used as the solvent of the zirconium precursor is not particularly limited, and methanol, ethanol, propanol, and butanol can be used.

After the primary mixed solution is prepared, an aqueous solution containing a tungsten precursor is added dropwise to the primary mixed solution and then mixed. As the tungsten precursor, sodium tungstate, ammonium tungstate, or a mixture thereof may be used, but the present invention is not limited thereto.

When the secondary mixture is made, a silica precursor is mixed with the secondary mixture. In order to form clusters of zirconium-tungsten oxide at a high density, a zirconium precursor and a tungsten precursor are sequentially added and reacted, and then a silica precursor is added to facilitate the formation of mesopores.

As the silica precursor, an alkoxy silane compound may be used. Specific examples of the alkoxysilane include, but are not limited to, tetramethyl orthosilicate, tetraethyl orthosilicate, and mixtures thereof.

In an embodiment of the present invention, the zirconium precursor, the tungsten precursor, and the silica precursor have atomic ratios of tungsten (W) / silicon (Si) of 0.1 / 1-0.14 / 1 and zirconium (Zr) It is preferable to use it so that the ratio is 0.01 / 1 to 0.14 / 1. If the atomic ratio of tungsten / silicon is less than 0.1 / 1 and the atomic ratio of zirconium / silicon is less than 0.01 / 1, clusters of zirconium-tungsten oxide are not formed smoothly and it is difficult to exhibit acid characteristics. Further, when the atomic ratio of tungsten / silicon exceeds 0.14 / 1 and the atomic ratio of zirconium / silicon exceeds 0.14 / 1, it is difficult to have regular medium pore and large specific surface area in a cylindrical form.

After mixing the silica precursor, the mixture is heated to form a suspension. Specifically, the hydrolysis and condensation reactions of the precursors are promoted through the heating process to produce a suspension of the sol-gel. At this time, the heating process is preferably performed at 30 to 120 ° C, more preferably at 80 to 120 ° C after the first heating at 30 to 60 ° C. At a temperature lower than 30 ° C, the reaction rate is slow. When the temperature exceeds 120 ° C, the reaction of the precursors accelerates and an irregular pore structure can be formed. The heating time is not particularly limited, but is preferably 20 to 30 hours each.

When the suspension is formed as such, it is filtered to recover the solid content, and then the obtained solid content is dried. The drying temperature is not particularly limited as long as the solvent can completely evaporate, and it is preferably 60 to 150 ° C.

The resulting dried material is then calcined in an oxygen atmosphere to make the bonding of the precursors more rigid and remove the surfactant to form the mesopores. The firing temperature is not particularly limited, and it is preferably 400 to 800 ° C. If the calcination temperature is lower than 400 ° C, the surfactant may not be completely removed, and if it exceeds 800 ° C, the regular pore structure may collapse.

Alcohol and Carboxylic acid  Method for producing an ester compound from a compound

The complex oxide catalyst of the present invention produced by the above-mentioned method has cylindrical pores and excellent acid characteristics. In particular, the composite oxide catalyst has a high density of clusters of zirconium-tungsten oxide that determines the acid property, and has a wide specific surface area and a large pore size, and thus can exhibit excellent acid catalyst performance in a liquid phase reaction.

Specifically, a high-value-added ester compound can be prepared by reacting an alcohol compound with a carboxylic acid compound in the presence of the composite oxide catalyst according to the present invention. The alcohol compound and the carboxylic acid compound are basic compounds that can be obtained in a large amount through a fermentation process of biomass resources and the like. The complex oxide catalyst of the present invention effectively converts these inexpensive compounds into high value-added ester compounds.

Examples of the alcohol compound include methanol, ethanol, propanol, butanol, pentanol, and mixtures thereof. Examples of the carboxylic acid compound include formic acid, acetic acid, propionic acid, butanoic acid, and mixtures thereof. The ester compound is produced from the alcohol compound and the carboxylic acid compound by removing water molecules. Therefore, various ester compounds can be prepared depending on the type of the alcohol and the carboxylic acid compound used in the reaction. For example, when ethanol and acetic acid are reacted, ethyl acetate can be formed.

The specific production process of the ester compound is as follows. A certain amount of alcohol and carboxylic acid compound and the composite oxide catalyst according to the present invention are introduced into the batch reactor and the reactor is completely sealed. Thereafter, while stirring the reactants, the temperature is raised to the desired reaction temperature, and the temperature is maintained for a certain time to prepare an ester compound.

The ratio of the alcohol to the carboxylic acid compound is not particularly limited, and it is preferable to use it in a molar ratio of 1: 1 in order to increase the yield of the ester compound. The amount of the catalyst to be used can be appropriately adjusted by those skilled in the art in consideration of the reaction activity and economy.

The esterification reaction generally increases the yield of the ester compound as the reaction temperature is higher and the reaction time is longer, and the reaction temperature and the reaction time are different depending on the kind of the reactants and the like, Can be appropriately selected.

Hereinafter, it will be described in more detail through Examples and Comparative Examples of the present invention.

Preparation of composite oxide catalyst

Example  One

Approximately 3.56 g (0.562 mmol) of Pluronic P123 and about 8.6 mL (0.089 mol) of hydrochloric acid were dissolved in about 100 mL (5.56 mol) of distilled water to prepare a first solution. Then, about 0.34 ml (0.355 mmol) of zirconium butoxide was dissolved in the same volume of ethanol to prepare a second solution. Also, about 1.17 g (3.55 mmol) of sodium tungstate dihydrate was dissolved in about 3 mL of distilled water to prepare a third solution.

While stirring the first solution, the second solution was added dropwise and mixed. The third solution was added dropwise to the mixed solution thus obtained and stirred for 1 hour to induce a cluster of zirconium-tungsten oxide to be formed well.

Subsequently, about 6.5 g (0.0312 mol) of tetraethylorthosilicate was added, followed by stirring at about 40 DEG C for about 24 hours. Thereafter, the temperature was raised to about 100 캜 and held for 24 hours for stabilization. The reaction was followed by filtration to obtain a solid form solid, which was dried overnight at 80 < 0 > C. Finally, the dried material was calcined at about 550 ° C. for about 3 hours in an oxygen atmosphere to prepare a composite oxide catalyst. The finished composite oxide catalyst is designated WZr-1.

Example  2

Zirconium butoxide, and about 1.23 g (3.72 mmol) of sodium tungstate dihydrate. The completed composite oxide catalyst was designated WZr-3.

Example  3

Zirconium butoxide in an amount of about 1.88 ml (1.95 mmol) and about 1.29 g (3.91 mmol) of sodium tungstate dihydrate. The completed composite oxide catalyst was designated WZr-5.

Comparative Example  One

Was prepared in the same manner as in Example 1, except that zirconium butoxide was not used and about 1.14 g (3.47 mmol) of sodium tungstate dihydrate was used. The finished composite oxide catalyst was designated WZr-0.

Comparative Example  2

A mixture of about 4.30 ml (4.48 mmol) of zirconium butoxide and about 1.48 g (4.48 mmol) of sodium tungstate dihydrate was prepared in the same manner as in Example 1. The finished composite oxide catalyst was designated WZr-10.

Experimental Example

1. Transmission electron microscope ( TEM ) analysis

1 is a transmission electron microscope (TEM) photograph of the catalysts of Examples 1 to 3 and Comparative Examples 1 and 2. Referring to FIG. 1, it can be seen that all the catalysts prepared in Examples 1 to 3 have regular cylindrical pores. On the other hand, in Comparative Example 1 in which Zr was not added and Comparative Example 2 in which Zr was added in an excess amount, it was confirmed that the pore structure partially disappeared.

2. Specific surface area  And pore size analysis

The specific surface area, pore size and pore volume of the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were measured by nitrogen adsorption / desorption experiments. Table 1 summarizes the specific surface area, pore size and pore volume of Examples 1 to 3 and Comparative Examples 1 and 2, and the results of the nitrogen adsorption / desorption curve are shown in FIG.

Specific surface area
(m ² / g) Average pore diameter
(nm) Total pore volume
(Cm3 / g) Example 1 (WZr-1) 629 5.1 0.874 Example 2 (WZr-3) 558 5.3 0.814 Example 3 (WZr-5) 477 5.5 0.699 Comparative Example 1 (WZr-0) 575 5.3 0.805 Comparative Example 2 (WZr-10) 346 4.4 0.413

Referring to Table 1 and FIG. 2, it can be seen that the catalysts prepared in Examples 1 to 3 have a large specific surface area of about 450 to 650 m < 2 > / g and large pores of about 5 to 6 nm. Also, the catalysts prepared in Examples 1 to 3 exhibited hysteresis indicating a regular mesopore structure in a range of relative pressure (P / P0) of 0.6 to 0.8, and exhibited a very uniform pore size distribution . These results indicate that the catalysts of Examples 1 to 3 have regular cylindrical pores of medium size and are in good agreement with the results of the previous TEM analysis.

On the other hand, in the case of Comparative Example 2, hysteresis was exhibited in a wide range of relative pressure of 0.4 to 0.8, indicating that the pore structure was unevenly distributed. It was also confirmed that the catalyst of Comparative Example 2 had a smaller pore size than the catalyst of Examples 1 to 3.

3. X-ray diffraction  ( XRD ) analysis

3 is a graph showing X-ray diffraction patterns of the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 and 2. Referring to FIG. 3, in the catalysts of Examples 2 to 3 and Comparative Example 2, no crystal structure was found except for the peak near 25 degrees formed by silica. On the other hand, in the case of Example 1 and Comparative Example 1, a peak corresponding to crystalline tungsten oxide was observed. On the other hand, Example 1 showed a smaller and wider peak size than Comparative Example 1, which means that the catalyst of Example 1 has a higher dispersion of smaller crystals than that of Comparative Example 1.

Preparation of ester compounds

Example  4

Butylacetate was prepared from 1-butanol and acetic acid using the catalyst prepared in Example 1. Specifically, a high pressure batch reactor was charged with about 18.5 ml (200 mmol) of 1-butanol and about 11.5 ml (200 mmol) of acetic acid. Then, about 0.2 g of the catalyst prepared in Example 1 was introduced, and the reactor was closed. While the reaction product was stirred, the temperature of the reactor was raised to about 120 degrees C to react for about 4 hours. The reaction results were analyzed using a GC equipped with an HP-Innowax column and an FID detector.

Example  5

The procedure of Example 4 was repeated except that the catalyst prepared in Example 2 was used.

Example  6

The procedure of Example 4 was repeated except that the catalyst prepared in Example 3 was used.

Comparative Example  3

The procedure of Example 4 was repeated except that the catalyst prepared in Comparative Example 2 was used.

Comparative Example  4

Was carried out in the same manner as in Example 4, except that HZSM-5 (zeolyst), a commercial zeolite catalyst, was used.

Comparative Example  5

The same procedure as in Example 4 was carried out except that a catalyst in which 30 wt% of tungsten oxide (WOx) was supported on a commercial zirconia carrier (prepared using an initial impregnation method) was used.

Comparative Example  6

The same procedure as in Example 4 was carried out except that a catalyst having 20 wt% of tungsten oxide (WOx) supported on a commercial zirconia carrier (prepared using an initial impregnation method) was used.

4 is a graph comparing the yields of butyl acetate obtained in the reaction experiments of Examples 4 to 6 and Comparative Examples 3 to 6. Referring to FIG. 4, in Examples 4 to 6, the yields were as low as 9% to as much as 20% as compared with Comparative Examples 3 to 6. In particular, the highest yield was obtained in the catalyst (WZr-1) of Example 5 because the cluster of zirconium-tungsten oxide, known as the active site of the acid catalysis reaction, It is interpreted that it is formed by the density.

Claims (11)

Tungsten oxide, zirconium oxide, and silicon oxide,
The atomic ratio of tungsten / silicon is 0.1 / 1 to 0.14 / 1,
The atomic ratio of zirconium / silicon is 0.01 / 1 to 0.14 / 1,
Composite oxide catalyst having regular medium pores in the form of a cylinder. The composite oxide catalyst according to claim 1, wherein the complex oxide catalyst has an atomic ratio of zirconium / tungsten of 0.1 / 1 to 0.9 / 1. The complex oxide catalyst of claim 1, wherein the complex oxide catalyst has a specific surface area of 400 m ² / g or more. The complex oxide catalyst of claim 1, wherein the medium pore has an average diameter of 4 to 8 nm. The composite oxide catalyst of claim 3, wherein the specific surface area is 400 to 700 m ² / g. Adding an alcohol solution containing a zirconium precursor dropwise to an acidic aqueous solution containing a surfactant,
Dropwise adding an aqueous solution containing a tungsten precursor to the primary mixed solution,
Mixing a silica precursor with the secondary mixed solution;
Heating the mixed liquid in which the silica precursor is mixed to form a suspension;
Filtering and drying the suspension; And
And calcining the dried material in an oxygen atmosphere. The method of claim 6, wherein the zirconium precursor, the tungsten precursor and the silica precursor are used such that the atomic ratio of tungsten / silicon is 0.1 / 1 to 0.14 / 1, and the atomic ratio of zirconium / silicon is 0.01 / 1 to 0.14 / 1. Method for producing a composite oxide catalyst, characterized in that. The method of claim 6, wherein the zirconium precursor is selected from the group consisting of zirconium ethoxide, zirconium butoxide, zirconium isopropoxide and mixtures thereof, the tungsten precursor is Sodium tungstate, ammonium tungstate, or mixtures thereof, and the silica precursor is tetramethyl orthosilicate, tetraethyl orthosilicate, or a mixture thereof. Method for producing a composite oxide catalyst. The method of claim 6, wherein the heating is performed by heating at 80 to 120 ° C. after the first heating at 30 to 60 ° C. 8. An ester compound is produced by reacting an alcohol compound with a carboxylic acid compound in the presence of the catalyst according to any one of claims 1 to 4 to produce an ester compound. The method of claim 10, wherein the alcohol compound is selected from the group consisting of methanol, ethanol, propanol, butanol, pentanol and mixtures thereof, wherein the carboxylic acid compound is formic acid, acetic acid, propane A process for producing an ester compound, characterized in that it is selected from the group consisting of acid (propionic acid), butanoic acid and mixtures thereof.

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