CN105121399A - Method for synthesizing acetophenone - Google Patents

Abstract

The present invention relates to a process for the synthesis of acetophenone by selective oxidation of ethylbenzene. According to the present invention, a method capable of synthesizing acetophenone in large quantities with a relatively high yield through a simplified process is provided.

Description

The synthetic method of acetophenone

technical field

The present invention relates to a process for the production of acetophenone, and more particularly, to a process for the production of acetophenone by selective oxidation of ethylbenzene.

Background technique

Acetophenone is an aromatic ketone that is a useful precursor for the preparation of various resins, drugs, fragrances, and the like.

Acetophenone can be obtained by various methods. For example, it can be synthesized by the Friedel-Craft reaction of benzene and acetic anhydride. However, this synthetic method has significant environmental disadvantages since a large amount of acidic wastewater is generated after the reaction is completed and mass production is difficult.

Furthermore, acetophenone can be obtained as a by-product when phenol is produced by the cumene process. However, according to this method, the amount of acetophenone that can be produced is determined according to the production conditions of the cumene process or the supply and demand of phenol.

Recently, a method for synthesizing acetophenone by an oxidation reaction of 1-phenylethanol, ethylbenzene, toluene, and the like in the presence of a catalyst containing palladium has been proposed. The main problems of this synthetic method include complicated process and prolonged reaction time. In this oxidation reaction, acetophenone is an intermediate oxidized to benzoic acid, and under oxidizing conditions, the reaction proceeds readily to benzoic acid.

Thus, the previously known synthesis methods of acetophenone involve relatively complicated processes, require expensive starting compounds, and have limitations in ensuring the yield of the synthesis reaction and high selectivity to acetophenone.

For example, Japanese Laid-Open Patent Publication No. 2008-0156347 discloses a novel method for preparing acetophenone using a supported palladium catalyst. Although this method can ensure the reaction yield to some extent, inorganic acids such as hydrochloric acid and the like should be added during the reaction at room temperature after the reaction at high temperature, which complicates the preparation process, takes a long reaction time, and requires expensive monomer (reactant), thereby reducing economic efficiency.

Furthermore, Japanese Laid-Open Patent Publication No. 1997-188647 discloses a method for producing acetophenone using ethanol or bromoethylbenzene, in which phosphonium salt or ammonium salt is used as a catalyst. However, this method also involves a complicated preparation process or should go through multiple steps, and includes a step of dropping 2.5 equivalents of bromine to ethylbenzene over 2 hours or more, thereby reducing production efficiency.

In addition, Japanese Laid-Open Patent Publication No. 2008-44858 discloses a method for synthesizing acetophenone using a mixed solvent of acetonitrile and water in the presence of a palladium catalyst. However, this method is uneconomical because many kinds of materials are required in the reaction, and the reaction should be performed under nitrogen atmosphere for about 16 hours, resulting in long and complicated process time.

Furthermore, Japanese Laid-Open Patent Publication No. 1993-309431 discloses the oxidation reaction of ethylbenzene in the presence of a heavy metal catalyst and a halogenated onium cocatalyst such as a halogenated quaternary ammonium salt or a halogenated quaternary phosphonium salt and the like Process for the preparation of acetophenone. However, according to this method, ethylbenzene is added after the cocatalyst and the heavy metal catalyst are added to the organic acid medium, and the temperature is raised to 100° C. or higher, thereby complicating the preparation process, and depending on the cocatalyst used, The conversion of the reactants or the selectivity of the final synthesis product is not sufficient.

Detailed description of the invention

technical problem

The object of the present invention is to provide a method capable of synthesizing acetophenone with a high yield through a simplified process.

Technical solutions

According to the present invention, there is provided a method for producing acetophenone, the method comprising at least one compound selected from the group consisting of imide-based compounds, basic compounds and water and a catalyst compound comprising at least cobalt as an active ingredient A step of oxidizing ethylbenzene in an organic solvent containing an organic acid in the presence of .

In the production method of acetophenone, the oxidation reaction may be performed in an organic solvent containing an organic acid in the presence of an imide-based compound, a basic compound, water or a basic compound and water, and a catalyst compound.

In the production method of acetophenone, the oxidation reaction may be performed in an organic solvent containing an organic acid in the presence of a catalyst compound containing cobalt as an active ingredient and an imide-based compound.

Herein, the imide-based compound may include an imide compound substituted with a reactive functional group at a nitrogen atom of an imide group.

In the production method of acetophenone, the oxidation reaction may be performed in an organic solvent containing an organic acid in the presence of a catalyst compound containing cobalt, manganese, and bromine as active ingredients and a basic compound.

Herein, the basic compound may be at least one compound selected from the group consisting of sodium carbonate, sodium hydroxide, sodium pyrophosphate, potassium carbonate, potassium hydroxide, and potassium pyrophosphate.

In the production method of acetophenone, the oxidation reaction may be performed in an organic solvent containing an organic acid in the presence of a catalyst compound containing cobalt, manganese, and bromine as active ingredients and water.

In the production method of acetophenone, the oxidation reaction may be performed in an organic solvent containing an organic acid in the presence of a catalyst compound containing cobalt, manganese, and bromine as active ingredients, a basic compound, and water.

The organic acid contained in the organic solvent may be a carboxylic acid having a carbon number of 2 to 20.

The oxidation reaction can be carried out by contacting an oxygen-containing gas with ethylbenzene. Furthermore, the oxidation reaction may be carried out at a pressure of 5 bar to 75 bar at a temperature of 50°C to 250°C.

Beneficial effect

The preparation method of acetophenone provided by the present invention exhibits high selectivity to acetophenone and simultaneously has a high conversion rate of raw material compounds, so that acetophenone can be produced in large quantities through a simplified process. Furthermore, this preparation method can be performed under mild conditions, which minimizes the corrosion of synthetic equipment and allows selective oxidation through an environmentally friendly process without the use of environmental pollutants.

specific implementation plan

Hereinafter, a production method of acetophenone according to a specific embodiment of the present invention will be explained.

First of all, the technical terms used herein are only for referring to specific embodiments and are not intended to limit the present invention. A singular form used herein includes a plural form thereof unless it has an express meaning to the contrary. The meaning of "comprising" or "comprising" used herein embodies specific properties, regions, integers, steps, operations, elements or components, and does not exclude the addition of other specific properties, regions, integers, steps, operations, elements or components.

According to the present invention, there is provided a method for producing acetophenone, the method comprising at least one compound selected from the group consisting of imide-based compounds, basic compounds and water and a catalyst compound comprising at least cobalt as an active ingredient A step of oxidizing ethylbenzene in an organic solvent containing an organic acid in the presence of .

The preparation method of acetophenone provided by the invention is a method for synthesizing acetophenone through the oxidation reaction of ethylbenzene, and ethylbenzene is a relatively cheap raw material compound.

However, as shown in Chemical Formula 1 below, in the oxidation reaction of ethylbenzene, various compounds other than acetophenone, such as phenol, benzoic acid, 1-phenylethanol, benzene Formaldehyde, styrene and similar.

[chemical formula 1]

Therefore, in order to increase the reaction efficiency of synthesizing acetophenone through the oxidation reaction of ethylbenzene, basically, the conversion rate of the raw material compound ethylbenzene should be high, and it is particularly important to provide high selectivity to acetophenone.

However, the production methods of acetophenone by the oxidation reaction of ethylbenzene known so far have a low conversion rate of ethylbenzene, or a low selectivity to acetophenone, and thus cannot satisfy the above two requirements at the same time.

In addition, in general, in the oxidation of ethylbenzene, if the reaction temperature is low, the preparation time may become longer, thereby exposing to heat for a long time, which reduces the reaction yield, and conversely, if the reaction temperature is high, by-products It may be produced in large quantities due to high temperature, making it difficult to obtain acetophenone with high purity or high selectivity.

In contrast, the method for producing acetophenone of the present invention is carried out in the presence of at least one compound selected from the group consisting of imide-based compounds, basic compounds, and water together with a catalyst compound containing at least cobalt as an active ingredient. Oxidation of benzene to obtain acetophenone with high selectivity and high ethylbenzene conversion. In addition, the synthesis of acetophenone by the method can be achieved by a simplified process, and it can be performed under relatively mild conditions, thereby reducing concerns about corrosion of synthesis equipment.

Specifically, since at least one compound selected from the group consisting of imide-based compounds, basic compounds, and water is used in the oxidation step of ethylbenzene, a high reaction yield can be ensured without raising the temperature , and in particular, acetophenone with high selectivity can be obtained.

It appears that at least one compound selected from the group consisting of imide-based compounds, basic compounds and water favors the formation of free radicals, thereby improving the activity of the catalyst compound used in the oxidation reaction even in the low temperature range.

It also appears that these compounds act as selective reaction inhibitors, thereby suppressing the production of by-products (mainly, acidic compounds) other than acetophenone during the oxidation of ethylbenzene.

As such, the oxidation reaction of ethylbenzene may be performed in the presence of at least one compound selected from the group consisting of an imide-based compound, a basic compound, and water, and a catalyst compound including at least cobalt as an active ingredient.

Herein, the imide-based compound of. In particular, it is advantageous to use imide-based compounds at a content of 1500 ppmw or more in order to ensure conversion of ethylbenzene and selectivity to acetophenone beyond optimum levels. However, if the imide-based compound is used too much, the oxidation reaction may be inhibited conversely, and the selectivity to acetophenone may decrease. Therefore, it is advantageous to use the imide compound at a content of 20,000 ppmw or less.

According to the present invention, specific examples of the imide-based compound may include an imide-based compound substituted with a reactive functional group at a nitrogen atom of an imide group. Herein, examples of the reactive functional group may include a hydroxyl group, an acetoxy group, a carboxyl group, and the like, and preferably, it may be a hydroxyl group.

A more specific example of the imide-based compound may include at least one compound selected from the group consisting of: N-hydroxyphthalimide, N-hydroxysuccinimide, N-hydroxy-1 ,8-Naphthalimide, N-Acetoxy-phthalimide, Trihydroxy-imino-cyanuric acid, N-Hydroxymaleimide, N-Hydroxychlorophthaloyl imine, N-hydroxychloronaphthalimide, and N-hydroxynitrophthalimide.

In addition, 0.1 ppmw to 70 ppmw, or 1 ppmw to 70 ppmw, or 1 ppmw to 50 ppmw, or 1 ppmw to 45 ppmw, or 5 ppmw to 45 ppmw based on the total weight of ethylbenzene and the organic solvent used in the oxidation reaction of ethylbenzene, Or 1 ppmw to 35 ppmw, or 5 ppmw to 30 ppmw of alkali ion concentration to add a basic compound that can be used in the oxidation reaction of ethylbenzene. Specifically, it is favorable to contain the basic compound at a concentration of alkali ions of 0.1 ppmw or more in order to sufficiently express the effect caused by the addition of the basic compound. However, if the basic compound is used too much, it may adversely affect the activity of the catalyst compound, the selectivity to acetophenone may decrease, and the oxidation reaction time may become longer, thereby increasing by-products. Therefore, it is advantageous to contain the basic compound at a concentration of alkali ions of 70 ppmw or less.

Specific examples of the basic compound may include at least one compound selected from the group consisting of sodium carbonate, sodium hydroxide, sodium pyrophosphate, potassium carbonate, potassium hydroxide, and potassium pyrophosphate.

In addition, it can be added in a content of 10 ppmw to 50,000 ppmw, or 100 ppmw to 30,000 ppmw, or 1000 ppmw to 20,000 ppmw based on the total weight of ethylbenzene and the organic solvent used in the oxidation reaction of ethylbenzene. of water in the oxidation reaction.

That is, it is favorable to contain water at a content of 10 ppmw or more in order to sufficiently express the effect caused by the addition of water. However, if water is contained in the reaction system more than necessary, the oxidation reaction may be inhibited to reduce the conversion rate of ethylbenzene. Therefore, it is favorable to contain water in a content of 50,000 ppmw or less.

Herein, at least one compound selected from the group consisting of imide-based compounds, basic compounds, and water may be applied to the oxidation reaction of ethylbenzene in various combinations. Specifically, these compounds can be used individually for the oxidation reaction of ethylbenzene; or two or more thereof, such as imide-based compounds and basic compounds, imide-based compounds and water, basic Compounds and water, and imide-based compounds and basic compounds and water can be used together. In particular, according to one embodiment, if a basic compound is used together with water for the oxidation reaction of ethylbenzene, acetophenone can be obtained with higher selectivity.

Meanwhile, the oxidation reaction of ethylbenzene is carried out in the presence of a catalyst compound containing at least cobalt as an active ingredient.

Herein, the catalyst compound may serve as a main catalyst for increasing the overall reaction rate including oxidation reaction.

The catalyst compound contains at least cobalt as an active ingredient, the catalyst compound may also contain other active ingredients other than cobalt, and the kind of active ingredient may vary depending on the compounds present in the reaction system.

For one example, if an imide-based compound is applied to the oxidation of ethylbenzene, the catalyst compound can exhibit high conversion of ethylbenzene and high selectivity to acetophenone without containing cobalt removal other active ingredients. That is, according to one embodiment of the present invention, the oxidation reaction may be performed in an organic solvent including an organic acid in the presence of a catalyst compound including cobalt as an active ingredient and an imide-based compound.

For another example, if basic compounds or water are applied to the oxidation of ethylbenzene, it may be advantageous that the catalyst compound also contains manganese and bromine as active ingredients in addition to cobalt, in order to ensure a high ethylbenzene Benzene conversion and high selectivity to acetophenone,.

That is, according to another embodiment of the present invention, the oxidation reaction may be performed in an organic solvent including an organic acid in the presence of a catalyst compound including cobalt, manganese, and bromine as active ingredients and a basic compound.

Furthermore, according to still another embodiment of the present invention, the oxidation reaction may be performed in an organic solvent including an organic acid in the presence of a catalyst compound including cobalt, manganese, and bromine as active ingredients and water.

Furthermore, according to yet another embodiment, the oxidation reaction may be performed in an organic solvent including an organic acid in the presence of a catalyst compound including cobalt, manganese, and bromine as active ingredients, a basic compound, and water.

Regarding active ingredients contained in the catalyst compound, cobalt and manganese may be contained in the form of metal salts or hydrates thereof, and bromine may be contained in the form of acid. Herein, the metal salt may include inorganic salts or organic salts, and specific examples thereof may include sulfates, nitrates, hydrochlorides, and carboxylates having a carbon number of 2 to 20. The carboxylic acid includes aliphatic carboxylic acid and aromatic carboxylic acid, and specific examples thereof may include acetic acid, butyric acid, palmitic acid, oxalic acid, propionic acid, benzoic acid, and the like.

The concentration of the active ingredient contained in the catalyst compound can be adjusted according to the oxidation reaction speed of ethylbenzene and the selectivity to acetophenone and the like.

For example, cobalt may be contained in a content of 5 ppmw to 300 ppmw, or 10 ppmw to 200 ppmw, or 20 ppmw to 100 ppmw based on the total weight of ethylbenzene and an organic solvent used in the oxidation reaction of ethylbenzene.

In addition, if other active ingredients other than cobalt are contained, manganese may be contained in a content of 50 ppmw to 500 ppmw, or 80 ppmw to 300 ppmw based on the total weight of the organic solvent and ethylbenzene; and may be contained in an amount based on the organic solvent and ethylbenzene The bromine is contained in an amount of 50 ppmw to 800 ppmw or 100 ppmw to 400 ppmw of the total weight.

That is, it is favorable that the catalyst contains an active ingredient exceeding the lower limit of the range in order to ensure the oxidation reaction speed and conversion rate of ethylbenzene. However, if the active ingredient is excessively contained in the catalyst compound, it may be difficult to control the selective oxidation reaction due to the rapid progress of the oxidation reaction, and thus the selectivity to acetophenone may decrease. Advantageously, therefore, the catalyst compound comprises the active ingredient below the upper limit of the range.

Meanwhile, the oxidation reaction of ethylbenzene may be performed using an organic solvent containing an organic acid, or it may be performed in an organic solvent.

Herein, the organic solvent may contain the organic acid in a content of 10 wt % or more, or 50 wt % or more, and it may include only the organic acid.

The organic acid contained in the organic solvent may be an acid having a carbon number of 2 to 20. The carboxylic acid may include aliphatic carboxylic acid or aromatic carboxylic acid, and specific examples thereof may include acetic acid, butyric acid, palmitic acid, oxalic acid, propionic acid, benzoic acid, and the like.

In addition, the amount of the organic solvent can be determined in consideration of the efficiency of the oxidation reaction and the like. As a non-limiting example, the organic solvent may be used in a weight ratio of 1:5 to 1:50, or 1:5 to 1:30, or 1:5 to 1:25 based on ethylbenzene.

The oxidation reaction of ethylbenzene can be performed by bringing an oxygen-containing gas into contact with ethylbenzene. Herein, the oxygen-containing gas may contain 10 vol% or more, or 20 vol% or more, or 50 vol% or more of oxygen, and the remaining amount of inert gas. The oxygen-containing gas may contain only oxygen. As a non-limiting example, air can be used for the oxidation of ethylbenzene.

The oxidation reaction of ethylbenzene may be carried out at a pressure of 5 bar to 75 bar, or 10 bar to 50 bar. That is, it is favorable that the oxidation reaction is performed at a pressure of 5 bar or more in order to sufficiently proceed the oxidation reaction. At the same time, since the oxidation reaction pressure is higher, the reaction rate may increase. However, in order to meet high pressure conditions, facility restrictions and equipment cost increases may be incurred. Advantageously, therefore, the oxidation reaction is carried out at a pressure of 75 bar or less.

The oxidation reaction of ethylbenzene may be performed at a temperature of 50°C to 250°C, or 70°C to 220°C, or 100°C to 200°C, or 110°C to 150°C. That is, if the oxidation reaction temperature is low, the reaction rate may decrease or the yield may decrease. On the contrary, if the oxidation reaction temperature is too high, it may be difficult to control the reaction rate, thereby increasing by-products and reducing the selectivity to acetophenone.

The time for performing the oxidation reaction of ethylbenzene can be determined in consideration of reaction yield and production amount of by-products, and the like, and thus is not particularly limited. As a non-limiting example, the oxidation of ethylbenzene may be performed for 30 minutes to 10 hours, or 1 hour to 8 hours, or 2 hours to 5 hours.

The oxidation reaction of ethylbenzene can be carried out under the stirring of the reactant, so as to improve the reaction efficiency. Herein, the stirring speed (though not specifically limited) may be advantageously controlled to be 10 rpm to 1000 rpm, or 150 rpm to 750 rpm, or 200 rpm to 500 rpm, in order to increase reaction efficiency.

Hereinafter, preferred examples are provided to aid understanding of the present invention. However, these examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

In the following Examples and Comparative Examples, component analysis of the product of the oxidation reaction was carried out using gas chromatography using a flame ionization detector. Conversion rate of ethylbenzene (=[content of initially introduced ethylbenzene-content of ethylbenzene contained in product]/[content of initially introduced ethylbenzene]*100) based on the result of component analysis The selectivities (=% content of acetophenone in the reaction product) to acetophenone were calculated and shown in Table 1 and Table 2 respectively below.

Example 1-1

Ethylbenzene and acetic acid were introduced into a 500 ml high pressure reactor equipped with a stirrer at a weight ratio of 1:19. In addition, 80 ppmw of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ ·4H ₂ O) based on the Co concentration, and 5000 ppmw of N-hydroxyphthalimide were introduced into the reactor. The inside of the high-pressure reactor was replaced with a nitrogen atmosphere, air of about 30 bar was supplied, and then, the temperature of the reactor was raised to about 130° C. to perform an oxidation reaction. Herein, the stirring speed was maintained at 400 rpm during the oxidation reaction, and the reaction was performed until there was no pressure change. After the oxidation reaction was completed, the inside of the reactor was cooled to room temperature, and then a product containing acetophenone was obtained.

Example 1-2

A product containing acetophenone was obtained by the same method as in Example 1-1, except that 5000 ppmw of N-hydroxysuccinimide was added instead of 5000 ppmw of N-hydroxyphthalimide.

Example 1-3

A product containing acetophenone was obtained by the same method as in Example 1-1, except that 5000 ppmw of N-hydroxy-1,8-naphthalimide was added instead of 5000 ppmw of N-hydroxyphthalimide .

Example 1-4

A product containing acetophenone was obtained by the same method as in Example 1-1, except that 2000 ppmw of N-hydroxy-1,8-naphthalimide was added instead of 5000 ppmw of N-hydroxyphthalimide .

Example 1-5

A product containing acetophenone was obtained by the same method as in Example 1-1, except that 3000 ppmw of N-hydroxy-1,8-naphthalimide was added instead of 5000 ppmw of N-hydroxyphthalimide .

Examples 1-6

A product containing acetophenone was obtained by the same method as in Example 1-1, except that 4000 ppmw of N-hydroxy-1,8-naphthalimide was added instead of 5000 ppmw of N-hydroxyphthalimide .

Comparative Example 1

A product containing acetophenone was obtained by the same method as in Example 1-1, except that 80 ppmw of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ .4H ₂ O) based on the concentration of Co, 80 ppmw based on the concentration of Mn, 160 ppmw manganese acetate tetrahydrate (Mn(CH ₃ COO ) ₂ 4H ₂ O) and 200 ppmw hydrogen bromide (HBr) based on Br concentration instead of cobalt acetate tetrahydrate were used as catalyst compounds and the oxidation reaction was carried out without adding N- Except for hydroxyphthalimide.

Comparative Example 2

A product containing acetophenone was obtained by the same method as in Example 1-1, except that ruthenium(III) chloride trihydrate (RuCl ₃ 3H ₂ O) was added as a catalyst instead of cobalt acetate tetrahydrate at 800 ppmw based on the Ru concentration compound and undergoes an oxidation reaction without the addition of N-hydroxyphthalimide.

Table 1

In Table 1, "AP" represents acetophenone, "BA" represents benzoic acid, "PE" represents 1-phenylethanol, and "Others" represents the remaining compounds other than AP, BA, and PE.

As can be seen from Table 1, it was confirmed that, with respect to Comparative Example 1 and Comparative Example 2, Examples 1-1 to 1-6 exhibited high conversions of ethylbenzene, and particularly in the case of The selectivity to acetophenone exhibited a marked difference. Among them, although Example 1-1 and Example 1-2 had similar conversion rates of ethylbenzene to those of Comparative Example 1 and Comparative Example 2, they exhibited significant differences in the selectivity to acetophenone. In addition, Comparative Example 2, in which a different kind of catalyst compound was used, had a low conversion rate of ethylbenzene compared to Examples, and also had low selectivity to acetophenone, thereby confirming poor reaction efficiency.

Example 2-1

Ethylbenzene and acetic acid were introduced into a 500 ml high pressure reactor equipped with a stirrer at a weight ratio of 1:19. In addition, 80 ppmw of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ .4H 2 O) based on the Co concentration, 160 ppmw of manganese acetate tetrahydrate (Mn(CH ₃ COO) _{2 .4H 2} O) based on the Mn concentration Hydrogen bromide (HBr) of 200 ppmw based on Br concentration and 200 ppmw of hydrogen bromide (HBr) based on Br concentration were separately introduced into the reactor, followed by introduction of 10 ppmw of sodium carbonate based on Na concentration. The interior of the high-pressure reactor was replaced with a nitrogen atmosphere, air of about 30 bar was supplied, and the temperature of the reactor was raised to about 130° C. to perform an oxidation reaction. Herein, the stirring speed was maintained at 400 rpm during the oxidation reaction, and the reaction was performed until there was no pressure change. After the oxidation reaction was completed, the inside of the reactor was cooled to room temperature, and then a product containing acetophenone was obtained.

Example 2-2

A product containing acetophenone was obtained by the same method as in Example 2-1, except that sodium carbonate was added in an amount of 25 ppmw (based on Na concentration).

Example 3-1

Ethylbenzene and acetic acid were introduced into a 500 ml high pressure reactor equipped with a stirrer at a weight ratio of 1:19. In addition, 80 ppmw of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ .4H 2 O) based on the Co concentration, 160 ppmw of manganese acetate tetrahydrate (Mn(CH ₃ COO) _{2 .4H 2} O) based on the Mn concentration And 200 ppmw of hydrogen bromide (HBr) based on the Br concentration were introduced into the reactor, followed by 5000 ppmw of water. The interior of the high-pressure reactor was replaced with a nitrogen atmosphere, air of about 30 bar was supplied, and then the temperature of the reactor was raised to about 130° C. to perform an oxidation reaction. Herein, the stirring speed was maintained at 400 rpm during the oxidation reaction, and the reaction was performed until there was no pressure change. After the oxidation reaction was completed, the inside of the reactor was cooled to room temperature, and then a product containing acetophenone was obtained.

Example 3-2

A product containing acetophenone was obtained by the same method as in Example 3-1, except that an oxidation reaction was performed while adding 8000 ppmw of water.

Example 3-3

A product containing acetophenone was obtained by the same method as in Example 3-1, except that an oxidation reaction was performed while adding 10,000 ppmw of water.

Example 4-1

A product containing acetophenone was obtained by the same method as in Example 2-1, except that an oxidation reaction was performed while 8000 ppmw of water was additionally added to the reactor.

Example 4-2

A product containing acetophenone was obtained by the same method as in Example 2-1, except that an oxidation reaction was performed while adding 25 ppmw (based on Na concentration) of sodium carbonate and adding 8000 ppmw of water.

Table 2

In Table 2, "AP" denotes acetophenone, "BA" denotes benzoic acid, "PE" denotes 1-phenylethanol, and "others" denotes the remaining compounds other than AP, BA, and PE.

As can be seen from Table 2, it was confirmed that, compared to Comparative Example 1 and Comparative Example 2, Examples 2-1 to 4-2 exhibited high conversions of ethylbenzene, and particularly in The selectivity to acetophenone exhibits a marked difference. In addition, although Comparative Example 1 used the same kind of catalyst compound as in Example, since the oxidation reaction was carried out without adding a basic compound and water, the conversion of ethylbenzene was relatively low, and the selectivity to acetophenone was significantly reduced.

Claims (20)

1. A method for producing acetophenone comprising in the presence of at least one compound selected from the group consisting of imide-based compounds, basic compounds and water and a catalyst compound comprising at least cobalt as an active ingredient , oxidation of ethylbenzene in organic solvents containing organic acids. 2. The method according to claim 1, wherein the oxidation reaction is carried out in an organic solvent containing an organic acid in the presence of an imide-based compound, a basic compound, water or a basic compound and water and the catalyst compound conduct. 3. The method of claim 1, wherein the oxidation reaction is performed in an organic solvent containing an organic acid in the presence of a catalyst compound containing cobalt as an active ingredient and an imide-based compound. 4. The method according to claim 1, wherein the catalyst compound comprises 5 ppmw to 300 ppmw of cobalt as an active ingredient based on the total weight of the organic solvent and the ethylbenzene. 5. The method of claim 1, wherein the imide-based compound is present in an amount of 1500 ppmw to 20,000 ppmw based on the total weight of the organic solvent and the ethylbenzene. 6. The method of claim 1, wherein the imide-based compound comprises an imide compound substituted with a reactive functional group at a nitrogen atom of an imide group. 7. The method of claim 1, wherein the imide-based compound is at least one compound selected from the group consisting of: N-hydroxyphthalimide, N-hydroxysuccinyl imine, N-hydroxy-1,8-naphthalimide, N-acetoxy-phthalimide, trihydroxy-imino-cyanuric acid, N-hydroxymaleimide, N- Hydroxychlorophthalimide, N-Hydroxychloronaphthalimide, and N-Hydroxynitrophthalimide. 8. The method according to claim 1, wherein the oxidation reaction is carried out in an organic solvent containing an organic acid in the presence of a catalyst compound containing cobalt, manganese and bromine as active ingredients and a basic compound. 9. The method according to claim 1, wherein the oxidation reaction is carried out in an organic solvent containing an organic acid in the presence of a catalyst compound containing cobalt, manganese and bromine as active ingredients and water. 10. The method according to claim 1, wherein the oxidation reaction is carried out in an organic solvent containing an organic acid in the presence of a catalyst compound containing cobalt, manganese and bromine as active ingredients and a basic compound and water. 11. The method of claim 1, wherein the catalyst compound comprises 5 ppmw to 300 ppmw cobalt, 50 ppmw to 500 ppmw manganese, and 50 ppmw to 800 ppmw bromine based on the total weight of the organic solvent and the ethylbenzene. 12. The method of claim 1, wherein the basic compound is present at a concentration of alkali ions of 0.1 ppmw to 70 ppmw based on the total weight of the organic solvent and the ethylbenzene. 13. The method of claim 1, wherein the basic compound is at least one compound selected from the group consisting of sodium carbonate, sodium hydroxide, sodium pyrophosphate, potassium carbonate, potassium hydroxide, and pyrophosphoric acid potassium. 14. The method of claim 1, wherein the water is present in an amount of 10 ppmw to 50,000 ppmw based on the total weight of the organic solvent and the ethylbenzene. 15. The method according to claim 1, wherein the organic acid contained in the organic solvent is a carboxylic acid having a carbon number of 2 to 20. 16. The method according to claim 1, wherein the organic solvent is used in a weight ratio of 1:5 to 1:50 based on ethylbenzene. 17. The method of claim 1, wherein the oxidation reaction is performed by contacting an oxygen-containing gas with ethylbenzene. 18. The method according to claim 1, wherein the oxidation reaction is carried out at a pressure of 5 bar to 75 bar. 19. The method of claim 1, wherein the oxidation reaction is performed at a temperature of 50°C to 250°C. 20. The method of claim 1, wherein the oxidation reaction is performed while stirring at 10 rpm to 1000 rpm.