JPH0848654A - Production of carbonate - Google Patents

Abstract

PURPOSE:To enable efficient production of carbonate which is useful as a starting substance for polycarbonate by ester-interchanging reaction between a carboxylate and an aromatic hydroxy compound followed by ester-interchanging reaction between the product and a carbonate. CONSTITUTION:A carboxylate of the formula: R<1>COOR<2>(R<1>, R<2> are each an alkyl, an alicyclic hydrocarbon, an arylalkyl), for example, methyl valerate is subjected to ester-interchanging reaction with an aromatic hydroxy compound of the formula: R<3>OH(R<3> is an aromatic group which may be substituted), for example, phenol, in the presence of a catalyst, for example, sulfuric acid, to give a carboxylic acid ester of the formula: R<1>COOR<3>. Then, the ester product and a carbonic acid ester of the formula: R<4>O-COOR<5> (R<4>, R<5> are each an alkyl, a cyclic hydrocarbon, an arylalkyl) are subjected to ester-interchanging reaction in the presence of a catalyst such as titanium tetra-isopropoxide to give a carbonate of the formula: R<3> O-COOR<6>(R<6> is a substituent selected from R<3>, R<4>, R<5>).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a carbonic acid ester by using a carbonic acid ester as a raw material and an aromatic hydroxy compound as raw materials.

The carbonic acid ester obtained is an industrially useful compound. For example, diphenyl carbonate, which is one kind of carbonic acid ester, is used as a raw material for polycarbonate.

[0003]

2. Description of the Related Art Conventionally, as a method for producing an aromatic carbonic acid ester, for example, a method of transesterifying an aliphatic carbonic acid ester with an aromatic hydroxy compound is known.
In particular, many proposals have been made regarding a method for producing diphenyl carbonate via methylphenyl carbonate by reacting dimethyl carbonate, which is one of aliphatic carbonates, and phenol, which is one of aromatic hydroxy compounds. There is. As a method for producing diphenyl carbonate, for example, a method using a Lewis acid or a compound generating a Lewis acid as a catalyst (Japanese Patent Publication No. 58-48537), a method using a titanium compound or an aluminum compound as a catalyst (Japanese Patent Publication No.
59-34170), a method using a lead compound as a catalyst (Japanese Patent Publication No. 64-3181), a method using an organic tin compound as a catalyst (Japanese Patent Application Laid-Open No. 54-48733), and the like.

The above methods are all carried out in a batch system, in which dimethyl carbonate is supplied to the reaction system while the by-product methanol is distilled off. Therefore, it has a drawback that the reaction time is long and the productivity is poor. Further, a method of adding benzene to the reaction system in order to efficiently distill off methanol (Japanese Patent Publication No. 62-8091) is also known. However, in this method, when recovering methanol, the recovering operation is complicated, such as extracting the methanol from a mixed solution of benzene and methanol with water. Therefore, even in this method, the productivity cannot be sufficiently improved.

Also known is a method of producing diphenyl carbonate by using a continuous multi-stage distillation column and reacting dimethyl carbonate with phenol in the distillation column (Japanese Patent Laid-Open No. 3-291257). However, this method has a drawback that the conversion rate of dimethyl carbonate is about 1.6 mol% to 24 mol% and the productivity is poor. In addition, this method also has a drawback that the number of steps required to obtain the desired product, diphenyl carbonate, is greater than that in the other methods.

The low conversion rate of dimethyl carbonate is due to the following reasons. That is, the transesterification reaction to form methylphenyl carbonate is an equilibrium reaction (equilibrium constant K = 10 ⁻³ to 10 ⁻⁴ ) which is extremely biased toward the original system side, and the reaction does not substantially proceed. .

Further, a method for producing diphenyl carbonate by reacting dimethyl carbonate and phenyl acetate (US Pat.
4,533,504) is known. According to this method, the conversion rate of dimethyl carbonate is as high as 70 mol% or more. However, in this method, when regenerating phenyl acetate from by-product methyl acetate, methyl acetate must be converted to diketene at a very high temperature, and this diketene must be reacted with phenol. Therefore, there is a problem in that the yield of the step of regenerating phenyl acetate is poor, and the utility cost is high.

[0008]

As described above, the above conventional manufacturing methods have drawbacks such as a low conversion rate and poor efficiency in synthesizing raw materials. Further, in the above-mentioned conventional production method for producing diphenyl carbonate by reacting dimethyl carbonate and phenol, there is a problem in that dimethyl carbonate and by-produced methanol are azeotroped, so that it is difficult to separate the two. are doing. Therefore, the above-mentioned conventional manufacturing method has a problem that the carbonic acid ester cannot be efficiently manufactured.

Therefore, there is a demand for a method capable of efficiently producing carbonic acid ester industrially. That is, the present invention has been made in view of the above conventional problems,
An object of the invention is to provide a novel production method capable of efficiently producing a carbonic acid ester by using a raw material carbonic acid ester and an aromatic hydroxy compound as raw materials.

[0010]

Means for Solving the Problems The inventors of the present application have made earnest studies to provide a new industrial production method of a carbonic acid ester, and as a result, the raw material carboxylic acid ester and an aromatic hydroxy compound were treated in the presence of a catalyst. It is possible to efficiently produce the carbonic acid ester by transesterifying the carboxylic acid ester and then transesterifying the carboxylic acid ester and the raw material carbonic acid ester in the presence of a catalyst. The present invention has been completed and the present invention has been completed.

That is, in order to solve the above-mentioned problems, the method for producing a carbonic acid ester according to the first aspect of the invention has the general formula (1) R ¹ COOR ² (1) (wherein R ¹ , R ² each independently represents an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group), and a raw material carboxylic acid ester represented by the general formula (2) R ³ OH (2) (wherein R is ³ represents an aromatic group which may have a substituent), and is subjected to transesterification in the presence of a catalyst with an aromatic hydroxy compound represented by the general formula (3) R ¹ COOR ³ (3) A carboxylic acid represented by the formula (wherein R ¹ represents an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group, and R ³ represents an aromatic group which may have a substituent). An ester is formed, and then the carboxylic acid ester and the general formula ( ^{) R 4 O-COOR 5 ......} (4) ( wherein, the R ^4, R ⁵ independently represents an alkyl group, the raw material carbonic acid ester represented by an alicyclic hydrocarbon group or an arylalkyl group) Is transesterified in the presence of a catalyst to give a compound represented by the general formula (5) R ³ O—COOR ⁶ (5) (wherein R ³ represents an aromatic group which may have a substituent). , R ⁶ represents a substituent selected from the group consisting of R ³ , the above R ⁴ and the above R ⁵ ).

In order to solve the above-mentioned problems, the method for producing a carbonic acid ester according to a second aspect of the present invention is characterized in that, in the method for producing a carbonic acid ester according to the first aspect, R ⁶ is R ^3. There is.

In order to solve the above-mentioned problems, the method for producing a carbonic acid ester according to a third aspect of the present invention is the method for producing a carbonic acid ester according to the first or second aspect, in which a general formula (6 ) R ¹ COOR ⁷ (6) (In the formula, R ¹ represents an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group, and R ⁷ represents the above R ⁴ and the above R ^{4.
And a} by-produced carboxylic acid ester represented by the formula ( ⁵ ) represents a substituent selected from the group consisting of ⁵ ).

In order to solve the above-mentioned problems, the method for producing a carbonic acid ester according to claim 4 is characterized in that, in the method for producing a carbonic acid ester according to claim 3, R ⁷ is equal to R ^2. There is.

In order to solve the above-mentioned problems, the method for producing a carbonic acid ester according to a fifth aspect of the present invention is the method for producing a carbonic acid ester according to any one of claims 1 to 4, wherein the starting carboxylic acid is used. It is characterized in that the ester and the aromatic hydroxy compound are brought into gas-liquid contact while transesterifying in the presence of a catalyst, and the produced carboxylic acid ester is continuously taken out of the reaction system.

In order to solve the above-mentioned problems, the method for producing a carbonic acid ester of the invention according to claim 6 is the method for producing a carbonic acid ester according to any one of claims 1 to 5, wherein the starting carboxylic acid is used. It is characterized in that the ester and the aromatic hydroxy compound are brought into gas-liquid contact while transesterifying in the presence of a catalyst to continuously withdraw the by-produced alcohol out of the reaction system.

In order to solve the above-mentioned problems, the method for producing a carbonic acid ester of the invention described in claim 7 is the method for producing a carbonic acid ester according to any one of claims 1 to 6, wherein the carboxylic acid ester is And raw carbonic acid ester,
In the presence of a catalyst, gas-liquid contact while transesterification,
It is characterized in that the produced carbonic acid ester is continuously withdrawn from the reaction system.

In order to solve the above-mentioned problems, the method for producing a carbonic acid ester according to claim 8 is the method for producing a carbonic acid ester according to any one of claims 1 to 7, wherein the above-mentioned carboxylic acid ester is used. And raw carbonic acid ester,
In the presence of a catalyst, gas-liquid contact while transesterification,
It is characterized in that the by-produced carboxylic acid ester produced as a by-product is continuously extracted from the reaction system.

In order to solve the above-mentioned problems, the method for producing a carbonic acid ester according to a ninth aspect of the present invention is the method for producing a carbonic acid ester according to any one of the first to eighth aspects, wherein The production and the production of carbonic acid ester are performed in the same reactor.

The method for producing a carbonic acid ester according to a tenth aspect of the present invention is the method for producing a carbonic acid ester according to any one of claims 1 to 9 in order to solve the above problems. It is characterized in that the production and / or the production of carbonic acid ester are carried out in a multistage distillation column.

In order to solve the above problems, the method for producing a carbonic acid ester according to the eleventh aspect of the present invention is the method for producing a carbonic acid ester according to any one of the first to ninth aspects, wherein It is characterized in that the production and / or the production of carbonic acid ester are carried out in a bubble column.

The present invention will be described in detail below. In the following description, for the sake of convenience, the reaction for producing the carboxylic acid ester represented by the general formula (3) is referred to as a first-stage reaction, and the reaction for producing the carbonic acid ester represented by the general formula (5) is referred to as This is referred to as the second-stage reaction. Further, if necessary, among the carbonic acid esters represented by the general formula (5), a carbonic acid ester in which the substituent represented by R ⁶ in the formula is the substituent R ⁴ or the substituent R ⁵ is a carbonic acid monoester. The carbonic acid ester in which the substituent represented by R ⁶ is the substituent R ³ is referred to as carbonic acid diester.

The above-mentioned second-stage reaction proceeds in two stages, a reaction for forming a carbonic acid monoester and a reaction for forming a carbonic acid diester. That is, first, one of the substituents R ⁴ and R ⁵ of the starting carbonic acid ester represented by the general formula (4) is replaced with the substituent R ^{3 of the} carboxylic acid ester represented by the general formula (3). Transesterified. As a result, a carbonic acid monoester is produced and a by-produced carboxylic acid ester is produced as a by-product. Next, the remaining substituent R ⁴ (R ⁵ ) of the carbonic acid monoester is transesterified with the substituent R ³ of the carboxylic acid ester represented by the general formula (3). As a result, a carbonic acid diester is produced and a by-produced carboxylic acid ester is produced as a by-product.

In the method for producing a carbonic acid ester according to the present invention, the raw material carboxylic acid ester represented by the general formula (1) used as a raw material is not particularly limited, but in the formula, R ¹ and R ^The substituent represented by 2 is a compound which is independently composed of an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group. The alkyl group preferably has 1 to 10 carbon atoms, the alicyclic hydrocarbon group preferably has 3 to 10 carbon atoms, and the arylalkyl group preferably has 7 to 10 carbon atoms.

Specific examples of the starting carboxylic acid ester represented by the above general formula (1) include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, cyclohexyl acetate, benzyl acetate, and 2-ethylhexyl acetate. ,
Methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, methyl isobutyrate, ethyl isobutyrate, propyl isobutyrate, methyl valerate, ethyl valerate,
Examples include propyl valerate, methyl isovalerate, ethyl isovalerate, propyl isovalerate, methyl hexanoate, ethyl hexanoate, propyl hexanoate, methyl heptanoate, ethyl heptanoate and the like.

Further, in the method for producing a carbonic acid ester according to the present invention, in order to favor the equilibrium of the transesterification reaction to the production system side and enhance the reaction efficiency (equilibrium conversion rate), the alcohol by-produced in the preceding reaction is used. It is preferable to take it out of the reaction system. Therefore, among the above-exemplified compounds, a raw material carboxylic acid ester having a boiling point higher than that of the by-produced alcohol is more preferable.

The by-produced carboxylic acid ester represented by the general formula (6), which is by-produced together with the carbonic acid ester, can preferably be reused as a raw material carboxylic acid ester. Therefore, the substituent R ² of the starting carboxylic acid ester represented by the general formula (1) and the substituents R ⁴ and R ^{5 of the} starting carbonic acid ester represented by the general formula (4) are the same as each other. Preferably there is. Furthermore, it is preferable to set the substituents R ² · R ⁴ · R ⁵ so that the by-produced carboxylic acid ester and the by-produced alcohol do not form an azeotropic composition. As a result, the by-produced carboxylic acid ester can be easily separated and recovered. Further, when all the by-produced carboxylic acid ester can be reused as the raw material carboxylic acid ester, the raw material carboxylic acid ester is not substantially consumed.

In the method for producing a carbonate ester according to the present invention, the aromatic hydroxy compound represented by the general formula (2) used as a raw material is not particularly limited, but is represented by R ³ in the formula. The substituent is a compound composed of an aromatic group. The above aromatic group may have a substituent.

Specific examples of the aromatic hydroxy compound represented by the general formula (2) include phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol and m-chlorophenol. , P-chlorophenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-isopropylphenol, m-isopropylphenol, p-isopropylphenol, o-methoxyphenol, m-methoxyphenol, p-methoxyphenol , Xylenols, α-naphthol, β-naphthol and the like. These aromatic hydroxy compounds may be appropriately mixed and used. Among the above-exemplified compounds, phenol is preferable from the industrial viewpoint.

In the method for producing a carbonic acid ester according to the present invention, the raw material carbonic acid ester represented by the general formula (4) used as a raw material is not particularly limited, but in the formula, R ⁴ , R ⁵ Is a compound in which the substituents represented by are each independently composed of an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group. The alkyl group preferably has 1 to 10 carbon atoms, and the alicyclic hydrocarbon group is
It preferably has 3 to 10 carbon atoms, and the arylalkyl group preferably has 7 to 10 carbon atoms.

Specific examples of the raw material carbonic acid ester represented by the above general formula (4) include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, diisopropyl carbonate, isomers of carbonic acid, and carbonic acid. Dipentyl isomers, dihexyl carbonate isomers, diheptyl carbonate isomers, dioctyl carbonate isomers, dinonyl carbonate isomers, didecyl carbonate isomers, dicyclohexyl carbonate, dibenzyl carbonate, diphenethyl carbonate isomers. Each isomer, each isomer of di (methylbenzyl) carbonate and the like can be mentioned. These starting carbonic acid esters may be appropriately mixed and used.
Of the above-exemplified compounds, dimethyl carbonate is preferable from the industrial viewpoint.

The reactor used for carrying out the first-stage reaction and / or the second-stage reaction is not particularly limited,
It may be a batch reactor, a flow reactor, or a gas-liquid contact reactor. Further, the flow reactor may be any of a fluidized bed type, a fixed bed type (simply an extrusion flow type when a homogeneous catalyst described later is used), and a stirring tank type. Then, the first-stage reaction and the second-stage reaction may be performed using the same reactor, or the first-stage reaction and the second-stage reaction may be performed using different reactors.

The first-stage reaction is an equilibrium reaction (equilibrium constant K = 10 ^-3 to 10 ^-4 ) which is extremely biased toward the original system. Therefore, in order to favor the equilibrium of the transesterification reaction to the production system side and increase the reaction efficiency (equilibrium conversion rate), it is preferable to extract the alcohol by-produced together with the carboxylic acid ester out of the reaction system.

Therefore, when the pre-stage reaction is carried out using a batch reactor and when the pre-stage reaction is carried out using a flow reactor such as a continuous tank type reactor, a distillation column is provided above the reactor. Is preferably installed, and the by-produced alcohol is continuously extracted (distilled) out of the reaction system. Further, when the alcohol is distilled off, it is preferable to sufficiently separate the alcohol and the raw material carboxylic acid ester.

In the case where the first-stage reaction is carried out using a gas-liquid contact type reactor, the starting carboxylic acid ester and the aromatic hydroxy compound are continuously supplied to the reactor to obtain the carboxylic acid ester as a product. It is efficient and preferable to continuously withdraw a high-boiling point component containing H from the lower part of the reactor in a liquid state and continuously withdraw a low-boiling point component containing an alcohol, which is a by-product, from the upper part of the reactor in a gaseous state.

The latter reaction is also an equilibrium reaction (equilibrium constant K = 10 ^-1 ~
10 ¹ ), the equilibrium of the transesterification reaction is not so biased toward the original system as compared with the previous reaction. Therefore, in the second-stage reaction, the reaction is more likely to proceed than in the first-stage reaction, but in order to make the above equilibrium advantageous to the production system side and increase the reaction efficiency (equilibrium conversion rate), in the same manner as in the first-stage reaction, the reaction with the carbonate ester is performed. It is preferable to extract the by-produced carboxylic acid ester, which is a by-product, out of the reaction system.

Therefore, when the post-stage reaction is carried out using a batch reactor and when the post-stage reaction is carried out using a flow reactor such as a continuous tank type reactor, a distillation column is provided above the reactor. Is preferably installed and the by-produced carboxylic acid ester by-produced is continuously withdrawn (distilled) out of the reaction system.
Further, when the by-produced carboxylic acid ester is distilled off, it is preferable to sufficiently separate the by-produced carboxylic acid ester and the carboxylic acid ester.

In the case where the latter stage reaction is carried out by using a gas-liquid contact type reactor, the carboxylic acid ester and the raw material carbonic acid ester are continuously supplied to the reactor so that the product containing the carbonic acid ester is highly reacted. A method in which the boiling point component is continuously withdrawn in a liquid state from the lower portion of the reactor, and a low boiling point component containing a by-product carboxylic acid ester which is a by-product is continuously withdrawn in a gaseous state from the upper portion of the reactor is efficient and preferable. .

The gas-liquid contact type reactor described above is not particularly limited. The gas-liquid contact type reactor has a structure in which a gas phase portion is present in the reactor and the low boiling point component produced can be continuously separated and removed into the gas phase portion, that is, so-called reactive distillation is carried out. Any structure can be used. In particular, a continuous multi-stage distillation column or a bubble column in which a higher boiling point raw material is supplied from the upper part of the reactor and a lower boiling point raw material is supplied from the lower part of the reactor can be preferably used.

The continuous multi-stage distillation column is preferably a distillation column having two or more stages excluding the top (top stage) and the bottom (bottom stage) of the column. As such a distillation column, for example, a packing column filled with packing such as Raschig ring, pole ring, interlocks saddle, Dickson packing, McMahon packing, sulzer packing; tray such as bubble bell tray, sieve tray, valve tray, etc. A commonly used distillation column such as a plate column using (plate) can be used. Also, a composite distillation column having both a tray and a packing layer can be used. Further, a plurality of multistage distillation columns may be used in combination. The above-mentioned number of plates indicates the number of plates in a plate column, and the theoretical number of plates in a packed column.

The above bubble column is preferably a bubble column in which a distributor such as a porous plate or a porous plate is installed in the gas introduction section at the lower part of the reactor in order to efficiently carry out gas-liquid contact. Also,
The packing may be gently filled in the bubble column, or
A gas re-distributor may be provided and a step may be provided to prevent back mixing of liquids. Further, a distillation column may be provided above the bubble column to improve the efficiency of gas-liquid separation.

Further, a plurality of the multistage distillation columns and the bubble columns may be connected. Thereby, the reaction efficiency can be further improved. Furthermore, by combining the batch reactor, the flow reactor, and the gas-liquid contact reactor,
It may be used in the first-stage reaction and / or the second-stage reaction.

When the boiling point of the raw material carbonic acid ester is lower than the boiling point of the by-product carboxylic acid ester in the second-stage reaction, the raw material carbonic acid ester reacts when the by-product carboxylic acid ester is extracted from the reaction system. It is taken out of the system. Therefore, when the boiling point of the raw material carbonic acid ester is lower than the boiling point of the by-product carboxylic acid ester, a combination of a batch type reactor or a flow type reactor and a gas-liquid contact type reactor is preferable. That is, first, a batch-type reactor or a flow-type reactor is used to allow the latter-stage reaction to proceed until an almost equilibrium state is reached, and a substantial amount of the raw material carbonic acid ester is converted into carbonic acid monoester or carbonic acid diester. Next, this reaction liquid is supplied to a gas-liquid contact type reactor, and gas-liquid contact, that is, reactive distillation is performed while the second-stage reaction proceeds, whereby the by-produced carboxylic acid ester is continuously withdrawn from the reaction system. This makes it difficult for the starting carbonic acid ester to be withdrawn from the reaction system, so that the reaction efficiency can be further improved.

In the method for producing a carbonic acid ester according to the present invention, the raw material carboxylic acid ester and the aromatic hydroxy compound are transesterified in the presence of a catalyst (first stage reaction). Further, the carboxylic acid ester and the starting carbonic acid ester are transesterified in the presence of a catalyst (second-stage reaction). The catalyst used in the first-step reaction and the catalyst used in the second-step reaction may be the same as or different from each other.

The catalyst used in the first-stage reaction includes mineral acids such as sulfuric acid; sulfonic acids such as paratoluenesulfonic acid; solid acids such as ion exchange resins and zeolites; bases such as sodium hydroxide; titanium tetraisopropoxide and zirconium. (IV) metal alkoxides such as isopropoxide; Lewis acids such as aluminum chloride and titanium tetrachloride; compounds that generate Lewis acids; metal phenoxides such as phenoxylead, phenoxytitanium; lead oxides; lead carbonates, etc. Lead salts;
Zirconium (IV) acetylacetonate, bis (acetylacetonato) copper (II), zinc (II) acetylacetonate, lithium acetylacetonate and other metal acetylacetonate complexes; dibutyltin oxide and other organotin compounds; titano Silicates; metal-substituted aluminum phosphates and the like.

The catalyst used in the second-stage reaction includes metal alkoxides such as titanium tetraisopropoxide and zirconium (IV) isopropoxide; Lewis acids such as aluminum chloride and titanium tetrachloride; and compounds that generate Lewis acids; phenoxy lead. , Metal phenoxides such as phenoxytitanium; organotin compounds such as dibutyltin oxide; titanosilicates; metal-substituted aluminum phosphates.
In addition, ordinary protonic acid, protonic base, solid acid and solid base can also be used as the catalyst.

When a solid heterogeneous catalyst is used, the catalyst may be held inside the reactor and brought into contact with the reaction solution. When a packed column or a composite distillation column is used as the reactor, a solid catalyst can be packed in place of a part or all of the packing packed in the column.

When a homogeneous catalyst is used, a solution containing the catalyst is fed into the reactor. For example, when a distillation column is used as the reactor, the catalyst can be supplied as a mixture with one or both of the raw material carbonic acid ester and the aromatic hydroxy compound. Alternatively, the solution mixed with the catalyst may be supplied to a feed stage of the raw material carbonic acid ester or the aromatic hydroxy compound in the distillation column, or may be fed to a stage different from the feed stage. However, in the distillation column, the more the area (stage) in which the catalyst is present, the more the contact frequency between the reaction liquid and the catalyst increases, and the better the reaction efficiency. Therefore, it is preferable to feed the catalyst to the upper stage of the distillation column as much as possible. Further, for example, when a bubble column is used as the reactor, the catalyst can be mixed with a raw material having a higher boiling point and supplied from the upper part of the bubble column. Alternatively, the reaction liquid may be brought into contact with the catalyst held inside the bubble column. When the homogeneous catalyst is used and the catalyst is not separated / removed after the completion of the first-stage reaction, the catalyst used in the first-stage reaction and the catalyst used in the second-stage reaction are preferably the same.

The catalyst concentration in the case of using a homogeneous catalyst has a lower limit of the total amount of the raw material carbonic acid ester and the aromatic hydroxy compound, that is, when a reactor other than the fixed bed type reactor is used for the raw material. It is 0.1 ppm, preferably 1 ppm, more preferably 10 ppm. Further, the upper limit value is an amount that dissolves in the reaction liquid inside the reactor in a saturated state, and is about 10% by weight, preferably 5% by weight, and more preferably 1% by weight. The amount of the catalyst in the case of using a heterogeneous catalyst is, relative to the raw materials, the lower limit value is 0.1% by weight, preferably 0.5% by weight, and more preferably, when using a batch reactor or a suspension bed reactor. It is 1% by weight. The upper limit is 40% by weight, preferably 30% by weight, more preferably 20% by weight.

The method of supplying the raw material to the reactor is not particularly limited, and a mixture prepared by mixing the raw material carbonic acid ester, the aromatic hydroxy compound and, if necessary, the raw material carboxylic acid ester is supplied. Alternatively, the starting carbonic acid ester, the aromatic hydroxy compound, and the starting carboxylic acid ester may be separately supplied. The raw material carbonic acid ester, the aromatic hydroxy compound, and the like may be supplied in a liquid state, a gas state, or a gas-liquid mixed state. However,
In order for the contact between the two to be carried out smoothly in the reactor, for example, when the reactor is a multi-stage distillation column, the stage for supplying the raw material with a higher boiling point is more than the stage for supplying the raw material with a lower boiling point. The upper stage is preferable. The high-boiling raw material may contain a part of the low-boiling raw material,
The low boiling point raw material may include a part of the high boiling point raw material.

The molar ratio of the starting carboxylic acid ester and the aromatic hydroxy compound in the first-stage reaction depends on the kind and amount of the catalyst to be used, the reaction conditions, etc.
The range of 50: 1 is preferable, the range of 1:20 to 20: 1 is more preferable, and the range of 1: 5 to 5: 1 is further preferable. As described above, the first-stage reaction is an equilibrium reaction that is highly biased toward the original system. Therefore, by using one of the raw material carboxylic acid ester and the aromatic hydroxy compound in a large excess, the reaction efficiency (equilibrium conversion rate) of the other can be increased. However, when the molar ratio of both is out of the above range, the raw material carboxylic acid ester or the aromatic hydroxy compound used in large excess must be recovered and recycled. For this reason, it is industrially disadvantageous and not preferable.

The molar ratio of the carboxylic acid ester and the starting carbonic acid ester in the second-stage reaction is preferably in the range of 1:50 to 50: 1, though it depends on the kind and amount of the catalyst used, reaction conditions and the like. The range of 1:20 to 20: 1 is more preferable, and the range of 1: 5 to 5: 1 is further preferable. By using one of the carboxylic acid ester and the starting carbonic acid ester in a large excess, the reaction efficiency (equilibrium conversion rate) of the other can be increased. However, when the molar ratio of both is out of the above range, the carboxylic acid ester or the raw material carbonic acid ester used in large excess must be recovered and recycled. For this reason, it is industrially disadvantageous and not preferable.

In the second-stage reaction, the reaction system may contain a raw material carboxylic acid ester, an aromatic hydroxy compound and the like which are unreacted substances in the first-stage reaction. However, when the amount of the unreacted product is relatively large, it is preferable to separate and recover the unreacted product before carrying out the subsequent reaction. The recovered unreacted material can be reused as a raw material for the first-stage reaction.

When operating the above reactor, factors that determine the operating conditions include operating temperature (reaction temperature), operating pressure, liquid retention time, and liquid holdup amount. Further, when the reactor is a distillation column, the number of stages, the reflux ratio, etc. may be further mentioned. When the reactor is a flow reactor, liquid hourly space velocity (LHSV) and the like may be further mentioned. The liquid hourly space velocity is
It is a value obtained by dividing the volumetric flow rate of the raw material flowing in the reactor by the volume of the reactor.

The operating temperature depends on the kinds of the starting carboxylic acid ester, the aromatic hydroxy compound, and the starting carbonic acid ester, the kind and amount of the catalyst, other conditions (factors), etc.
The minimum temperature is 100 ° C, preferably 140 ° C, more preferably
It is 160 ° C, and the upper limit temperature is 350 ° C, preferably 300 ° C. When the operating temperature is lower than 100 ° C., the catalyst activity becomes low, the reaction time becomes long, and the productivity is lowered, which is not preferable. If the operating temperature is higher than 350 ° C., side reactions such as dehydration reaction or decarboxylation reaction to produce ethers (diaryl ethers, alkylaryl ethers, etc.) are likely to occur, which is not preferable. Furthermore, the pressure inside the reactor is too high, which is not preferable.

The operating pressure may be any of reduced pressure, normal pressure and increased pressure, and the kinds of the starting carboxylic acid ester, the aromatic hydroxy compound and the starting carbonic acid ester, the kind and amount of the catalyst, and other conditions. Depending on (factor) etc., it is about 1 mm
Hg to 100 kg / cm ² is preferable, 5 mmHg to 50 kg / cm ²
The range of is more preferable.

The holdup amount and the number of stages are closely related to the reaction time, that is, the residence time. That is, in order to increase the equilibrium conversion rate, it is necessary to lengthen the residence time to some extent, and in order to lengthen the residence time, it is necessary to increase the hold-up amount or increase the number of stages.
Of these, it is preferable to increase the hold-up amount, but if the hold-up amount is increased to a certain level or more, flooding will occur. Therefore, the volume ratio of the hold-up amount to the empty column volume (volume) of the reactor is preferably in the range of 0.005 to 0.75, and more preferably in the range of 0.01 to 0.5. In addition, when the number of stages is increased, it is preferable that the number of stages is about 2 to 100 in consideration of the cost, height limit, utility cost, fixed cost, etc. when manufacturing the reactor. When the number of stages is increased, the boiling point difference between the starting carboxylic acid ester and the alcohol by-produced in the first-stage reaction is relatively small, and in the latter-stage reaction, the carboxylic acid ester and the carbonic acid monoester or the by-produced carboxylic acid by-produced. When the boiling point difference with the acid ester is relatively small, the efficiency of gas-liquid separation is improved.

The reflux ratio is preferably in the range of 0-100,
The range of 0 to 50 is more preferable, and the range of 0 to 25 is further preferable. In the first-stage reaction, when the starting carboxylic acid ester and the by-produced alcohol form an azeotropic composition, the reflux ratio is preferably 0 or a relatively small value. Further, when the boiling point difference between the raw material carboxylic acid ester and the by-produced alcohol is relatively small, the reflux ratio is preferably set to a relatively large value. Similarly,
In the second-stage reaction, when the boiling point difference between the carboxylic acid ester and the carbonic acid monoester or by-product carboxylic acid ester produced as a by-product is relatively small, the reflux ratio is preferably set to a relatively large value.

The liquid hourly space velocity (LHSV) depends on the kinds of the starting carboxylic acid ester, the aromatic hydroxy compound and the starting carbonic acid ester, the kind and amount of the catalyst, the operating temperature, other conditions (factors), etc. lower limit 0.05hr ^-1, preferably 0.1 hr ^-1, more preferably 0.2 hr ^-1, the upper limit is 5
It is 0 hr ^-1 , preferably 20 hr ^-1 .

When a batch type reactor is used as the reactor, the starting carboxylic acid ester, the aromatic hydroxy compound, the starting carbonic acid ester and the catalyst are charged in a predetermined amount and the predetermined reaction is performed while stirring. Perform the first-stage reaction and / or the second-stage reaction at a temperature. The reaction pressure is the sum of the vapor pressures of the above compounds, but a gas inert to the reaction system (such as nitrogen gas) may be introduced to increase the pressure. The reaction time depends on the type and amount of catalyst, reaction temperature, etc.,
0.01 hours to 100 hours is preferable, 0.1 hours to 50 hours
More preferably within the range of time.

When a heterogeneous catalyst is used, the heterogeneous catalyst can be easily removed and recovered from the reaction solution by using a known method such as centrifugation or filtration after the reaction. When a homogeneous catalyst is used, the homogeneous catalyst can be easily separated and recovered from the reaction solution by using a known method such as distillation after the reaction.
When the same homogeneous catalyst is used for the first-stage reaction and the second-stage reaction, the second-stage reaction can be started without separating the catalyst after the completion of the first-stage reaction.

After the completion of the second-stage reaction, the catalyst is separated by the above-mentioned method, and then the known method such as distillation, extraction, recrystallization or the like is used to obtain the carbonate represented by the general formula (5). That is, the target carbonic acid diester can be easily isolated. In addition, if necessary, by-product carboxylic acid ester or carbonic acid monoester, which is a by-product,
Unreacted raw material carbonic acid ester, aromatic hydroxy compound and the like can be easily separated and recovered.

In the method for producing a carbonate ester according to the present invention, a solvent may be added to the reaction system, that is, the reaction solution, if necessary. Examples of the solvent added to facilitate the reaction operation include compounds inert to the above reaction system, such as ethers, aliphatic hydrocarbons, aromatic hydrocarbons and halogenated hydrocarbons. Further, in the first-stage reaction, when the raw material carboxylic acid ester and the by-produced alcohol form an azeotropic composition, an azeotropic composition having a lower azeotropic point than the azeotropic point of the azeotropic composition is used as the alcohol. It is preferable that the solvent formed between the two coexists in the reaction system. For example, when the alcohol is methanol, suitable solvents include compounds such as benzene and cyclohexane. The solvent forms an azeotropic composition having a relatively low azeotropic point with methanol. For this reason, azeotropy of the raw material carboxylic acid ester and methanol is suppressed, so that the two can be easily separated and the equilibrium conversion rate can be improved. Even when the raw material carboxylic acid ester and alcohol do not form an azeotropic composition, a solvent that forms an azeotropic composition having a low azeotropic point with alcohol in order to further facilitate the separation of the two. To
You may make it coexist in a reaction system. Further, in order to easily remove alcohol from the reaction system, an inert gas (nitrogen gas or the like) to the reaction system can be introduced from the lower part of the reactor.

Next, a method for producing the carbonic acid ester represented by the general formula (5) using the above-mentioned carbonic acid ester as a raw material and an aromatic hydroxy compound as a raw material will be described below. First, regarding an example of a method for producing a carbonate ester using a reactor having a batch reactor as a reactor,
This will be described with reference to FIG.

As shown in FIG. 1, the above reactor comprises a batch reactor 1 as a reactor, a distillation column 2, a condenser 5, a pump 6 and the like.

The batch reactor 1 transesterifies the starting carboxylic acid ester and the aromatic hydroxy compound, and transesterifies the produced carboxylic acid ester and the starting carbonic acid ester. The batch reactor 1 has pressure resistance and includes a stirring device 1a and a heating device 1b. A raw material supply pipe 10 is connected to the batch reactor 1. At the bottom of the batch reactor 1, the extraction tube 1
1 is connected. Further, a distillation column 2 is installed above the batch reactor 1. The extraction pipe 11 can extract the reaction liquid in the batch reactor 1 to the outside of the reaction system.

The distillation column 2 continuously distills off low-boiling components including by-products such as alcohol or by-produced carboxylic acid ester from the reaction solution. The bottom of the distillation column 2 is connected to the upper part of the batch reactor 1. Further, the top of the distillation column 2 is connected to the condenser 5 via the conduit 13.

The condenser 5 condenses and liquefies the distillate of the distillation column 2. The condenser 5 is connected to the top of the distillation column 2 via a conduit 13, and is connected to the pump 6 via a conduit 14. Further, the condenser 5 is provided with an adjusting pipe 15 having a pressure adjusting valve 16. And conduit 1
No. 4 is branched so that a part of the distillate can be continuously withdrawn from the reaction system.

The pump 6 is adapted to return the distillate to the distillation column 2 at a predetermined reflux ratio. The pump 6 is connected to the condenser 5 via a conduit 14, and is connected to the top of the distillation column 2 via a conduit 17.

Next, an example of a method for producing a carbonic acid ester using the reactor having the above structure will be described.

First, a first-stage reaction is carried out to form a carboxylic acid ester. That is, through the raw material supply pipe 10, the raw material carboxylic acid ester, the aromatic hydroxy compound, the catalyst,
And, if necessary, a mixture comprising a solvent and the like is charged into the batch reactor 1. Next, the reaction solution is heated with stirring to raise the temperature. Then, the raw material carboxylic acid ester and the aromatic hydroxy compound are transesterified at a predetermined temperature in the presence of a catalyst.

Then, the low boiling point component containing by-products such as alcohol is distilled in the distillation column 2 to distill off the alcohol. The alcohol-containing gas is continuously condensed in the condenser 5 to be a distillate. A part of the above distillate is pump 6
Is returned to the top of the distillation column 2 at a predetermined reflux ratio, and the remaining distillate is continuously withdrawn from the reaction system. That is,
The by-product alcohol is continuously taken out of the reaction system as a distillate.

During the reaction of the first stage reaction, a low boiling point raw material,
For example, the raw material carboxylic acid ester may be continuously supplied to the batch reactor 1 via the raw material supply pipe 10. Also,
In order to facilitate the distillation of alcohol, the above solvent or inert gas may be continuously supplied to the batch reactor 1 via the raw material supply pipe 10. By setting the number of stages of the distillation column 2 and the reflux ratio etc. to optimum values, alcohol can be recovered with high purity.

After the completion of the first-step reaction, the alcohol, unreacted starting carboxylic acid ester, aromatic hydroxy compound and the like are distilled off. As a result, the produced carboxylic acid ester and the catalyst are left in the batch reactor 1.
In addition, a part of unreacted raw material carboxylic acid ester, aromatic hydroxy compound and the like may remain in the batch reactor 1. Further, after the completion of the first-stage reaction, the extraction pipe 11
The reaction solution in the batch reactor 1 is drawn out of the reaction system through the reactor, and alcohol, unreacted starting carboxylic acid ester, aromatic hydroxy compound, etc. are extracted from the reaction solution using another distillation apparatus (not shown). May be distilled off. In this case, the residue may be returned to the batch reactor 1.

Then, a second-stage reaction is carried out to form a carbonic acid ester. That is, the raw material carbonic acid ester or the like is charged into the batch reactor 1 through the raw material supply pipe 10. Next, the reaction solution is heated with stirring to raise the temperature. Then, the carboxylic acid ester and the raw material carbonic acid ester are transesterified at a predetermined temperature in the presence of a catalyst.

In the latter-stage reaction, when the boiling point of the starting carbonic acid ester is lower than the boiling point of the by-produced carboxylic acid ester produced as a by-product, the batch reactor 1 is preferably closed. That is, in a state where the batch reactor 1 is sealed, the second-stage reaction is allowed to proceed until an almost equilibrium state is reached, and then the distillation column 2 or the like is used to produce by-products such as by-produced carboxylic acid ester and unreacted raw materials. It is preferable to distill off the carbonic acid ester to further advance the second-stage reaction. When the boiling point of the raw material carbonic acid ester is higher than the boiling point of the by-produced carboxylic acid ester that is a by-product, the by-product carboxylic acid ester that is a by-product is obtained by using the distillation column 2 or the like while performing the subsequent reaction. You can distill off. In this case, the by-produced carboxylic acid ester can be recovered with high purity. When the by-produced carboxylic acid ester can be reused as the raw material carboxylic acid ester, the raw material carboxylic acid ester is not substantially consumed.

After completion of the second-stage reaction, the by-produced carboxylic acid ester, unreacted carboxylic acid ester, starting carbonic acid ester and the like are distilled off. Then, the target carbonic acid diester is isolated by, for example, rectifying. The catalyst left in the batch reactor 1 can be easily recovered and can be reused. In addition, after the end of the latter reaction,
The reaction liquid in the batch reactor 1 is extracted to the outside of the reaction system through the extraction pipe 11, and by-product carboxylic acid ester and unreacted carboxylic acid ester are extracted from the reaction liquid by using another distillation apparatus (not shown). Alternatively, the raw material carbonic acid ester and the like may be distilled off. In addition, the target carbonic acid diester can be isolated by extraction, recrystallization, or the like instead of rectifying.

By carrying out the above reaction operation, the carbonate ester can be efficiently produced.

Next, an example of a method for producing a carbonic acid ester using a reactor having a continuous tank reactor as a reactor will be described with reference to FIG. For the sake of convenience of explanation, the components having the same functions as those of the reactor (FIG. 1) will be designated by the same reference numerals, and the description thereof will be omitted. Moreover, in the following description, the case where the boiling point of the raw material carbonic acid ester is lower than the boiling point of the byproduct carboxylic acid ester will be taken as an example.

As shown in FIG. 2, the reactor described above comprises reactors 21, 22 and 23, a distillation column 2.2, a condenser 5.5,
It is also composed of the pumps 6 and 6 and the like.

The reactor 21 transesterifies the raw material carboxylic acid ester and the aromatic hydroxy compound to produce a carboxylic acid ester. The reactor 21 is a stirring device 2
1a and the heating device 21b are provided. In the reactor 21,
The raw material supply pipe 10 is connected. A conduit 24 is connected to the bottom of the reactor 21. Further, a distillation column 2 and the like are installed above the reactor 21. Conduit 2
4, a conduit 24a is connected to the reaction liquid extracted from the reactor 21, and a raw material carbonate ester or the like can be mixed through the conduit 24a.

The reactors 22 and 23 transesterify the carboxylic acid ester and the raw material carbonic acid ester. Reactor 2
No. 2 can be hermetically sealed and is provided with a stirring device 22a and a heating device 22b. A conduit 24 is connected to the reactor 22. A conduit 25 is connected to the bottom of the reactor 22. The reactor 23 includes a stirring device 23a and a heating device 23b. Reactor 2
A conduit 25 is connected to 3. Also, the reactor 23
A withdrawal pipe 11 is connected to the bottom of the. Further, the distillation column 2 and the like are installed above the reactor 23. Other configurations of the reactor are the same as those of the reactor (FIG. 1).
The configuration is the same as that of.

Next, an example of a method for producing a carbonic acid ester using the reactor having the above structure will be described. For convenience of explanation, the explanation of the same operations as those in the reaction device (FIG. 1) will be simplified.

First, a first-stage reaction is carried out to produce a carboxylic acid ester. That is, through the raw material supply pipe 10, the raw material carboxylic acid ester, the aromatic hydroxy compound, the catalyst,
And, if necessary, a mixture including a solvent and the like is charged into the reactor 21. Then, the raw material carboxylic acid ester and the aromatic hydroxy compound are transesterified at a predetermined temperature, and the by-product such as alcohol is distilled off.

Then, a second-stage reaction is carried out to form a carbonic acid ester. That is, after the completion of the first-stage reaction, the reaction liquid in the reactor 21 is transferred to the reactor 22 via the conduit 24. Further, the raw material carbonate ester or the like is mixed with the reaction liquid via the conduit 24a. Then, the carboxylic acid ester and the raw material carbonic acid ester are transesterified at a predetermined temperature.

In the reactor 22, in a sealed state,
The latter-stage reaction is allowed to proceed until the equilibrium state is reached. Then, the reaction liquid in the reactor 22 is transferred to the reactor 23 via the conduit 25. In the reactor 23, by-products such as by-produced carboxylic acid ester and unreacted starting carbonic acid ester are distilled off by using the distillation column 2 and the like, and the second-stage reaction is further advanced.

After completion of the second-stage reaction, the by-produced carboxylic acid ester, unreacted carboxylic acid ester, starting carbonic acid ester and the like are distilled off. Then, the target carbonic acid diester is isolated by, for example, rectifying. Reactor 2
The catalyst left in 3 can be easily recovered and reused.

By carrying out the above reaction operation, the carbonate ester can be efficiently produced. When the boiling point of the raw material carbonic acid ester is higher than the boiling point of the by-produced carboxylic acid ester produced as a by-product, the reactor 22 may not be provided. Further, the reaction device may have a configuration in which a plurality of reactors 21, 22, and 23 are connected in series. Thereby, the reaction efficiency (equilibrium conversion rate) can be further improved.

Next, an example of a method for producing carbonate ester using a reaction apparatus having a multistage distillation column as a reactor will be described with reference to FIG. For the sake of convenience of explanation, the components having the same functions as those of the reactor (FIG. 2) are designated by the same reference numerals, and the description thereof will be omitted. Moreover, in the following description, the case where the boiling point of the raw material carbonic acid ester is lower than the boiling point of the byproduct carboxylic acid ester will be taken as an example.

As shown in FIG. 3, the above-mentioned reactor comprises a continuous multi-stage distillation column 31, 32 as a reactor and a reactor 3.
3, a reboiler 4.4, a condenser 5.5, a pump 6.6 and the like.

In the continuous multi-stage distillation column 31, the raw material carboxylic acid ester and the aromatic hydroxy compound are subjected to gas-liquid contact while transesterifying. In the continuous multi-stage distillation column 31,
The raw material supply pipes 8 and 10 are connected. The bottom of the continuous multistage distillation column 31 is connected to the reboiler 4 via conduits 34 and 35. Furthermore, continuous multi-stage distillation column 3
The top of column 1 is connected to the condenser 5 via a conduit 13. In the continuous multi-stage distillation column 31, the raw material supply pipe 8
Are connected above the raw material supply pipe 10. The raw material supply pipe 10 may be connected to the bottom of the tower.

The raw material supply pipe 8 continuously supplies a mixture containing a raw material carboxylic acid ester and an aromatic hydroxy compound having a higher boiling point to the continuous multistage distillation column 31. The raw material supply pipe 10 continuously supplies a mixture containing a raw material carboxylic acid ester and an aromatic hydroxy compound having a lower boiling point to the continuous multistage distillation column 31. Incidentally, when there is almost no difference between the boiling point of the raw material carboxylic acid ester and the boiling point of the aromatic hydroxy compound,
One of the raw material supply pipes 8 and 10 may be omitted, and the mixture of the raw material carboxylic acid ester and the aromatic hydroxy compound may be continuously supplied to the continuous multistage distillation column 31.

The reboiler 4 is connected to the bottom of the continuous multistage distillation column 31 via conduits 34 and 35. The reboiler 4 heats the bottom liquid extracted through the conduit 34 and returns it to the bottom through the conduit 35. That is, the reboiler 4 heats and circulates the bottom liquid. And the conduit 34
Is branched, and a part of the bottom liquid of the tower is used as the bottom liquid in the reactor 3
Transfer to 3 continuously. Further, the conduit 34 has a conduit 34a
Is connected so that the raw material carbonate ester or the like can be mixed with the above-mentioned bottom liquid via the conduit 34a.

Reactor 33 and continuous multistage distillation column 32
Transesterifies the carboxylic acid ester and the raw material carbonic acid ester. The reactor 33 is a flow reactor. A conduit 34 is connected to the bottom of the reactor 33. A conduit 36 is connected to the upper portion of the reactor 33. A pressure adjusting valve 37 is attached to the conduit 36.

In the continuous multi-stage distillation column 32, the carboxylic acid ester and the raw material carbonic acid ester are subjected to transesterification and brought into gas-liquid contact. A conduit 36 is connected to the middle part of the continuous multi-stage distillation column 32. In addition, the continuous multi-stage distillation column 32
The bottom of the column is connected to the reboiler 4 via the extraction pipe 11 and the conduit 38. Further, the top of the continuous multistage distillation column 32 is connected to the condenser 5 via the conduit 13. The outlet pipe 11 is branched so that a part of the bottom liquid can be continuously withdrawn as a bottom liquid out of the reaction system. The other structure of the reaction device is the same as that of the reaction device (FIG. 2).

Next, an example of a method for producing a carbonic acid ester using the reactor having the above structure will be described. For the sake of convenience of description, the description of the same operations as those in the reaction device (FIG. 2) will be simplified.

First, a first-stage reaction is carried out to produce a carboxylic acid ester. That is, through the raw material supply pipes 8 and 10,
The mixture containing the raw material carboxylic acid ester and the mixture containing the aromatic hydroxy compound are continuously supplied to the continuous multistage distillation column 31. The raw material carboxylic acid ester and aromatic hydroxy compound supplied to the continuous multi-stage distillation column 31 are subjected to gas-liquid contact while undergoing transesterification in the presence of a catalyst,
That is, it is reactively distilled. In addition, by-products such as alcohol are continuously withdrawn as a distillate. When the catalyst is a homogeneous catalyst, the catalyst is continuously supplied to the continuous multistage distillation column 31 together with the raw material carboxylic acid ester and / or the aromatic hydroxy compound. When the catalyst is a heterogeneous catalyst, the catalyst is held inside the continuous multistage distillation columns 31 and 32 and inside the reactor 33. Furthermore, when a solvent is used, the solvent may be continuously supplied to the continuous multistage distillation column 31 via the raw material supply pipe 10, but a solvent supply pipe may be separately provided.

Then, a second-stage reaction is carried out to form a carbonic acid ester. That is, the bottoms of the continuous multistage distillation column 31 is continuously transferred to the reactor 33 via the conduit 34. Further, the raw material carbonate ester or the like is continuously mixed with the bottom liquid through the conduit 34a. Then, the carboxylic acid ester and the raw material carbonic acid ester are transesterified at a predetermined temperature.

In the reactor 33, the second-stage reaction preferably proceeds until the equilibrium state is reached. Then, the reaction liquid in the reactor 33 is continuously supplied to the continuous multistage distillation column 32 via the conduit 36.

In the continuous multistage distillation column 32, the second-stage reaction further proceeds. That is, the carboxylic acid ester and the raw material carbonic acid ester supplied to the continuous multistage distillation column 32 are subjected to gas-liquid contact while undergoing transesterification in the presence of a catalyst,
That is, it is reactively distilled. In addition, by-products such as by-product carboxylic acid ester, unreacted starting carbonic acid ester, and aromatic hydroxy compound are continuously withdrawn as a distillate.

The above-mentioned distillate is preferably separated into unreacted starting carbonic acid ester and other components containing by-produced carboxylic acid ester by using a known method such as distillation. The above-mentioned recovered raw material carbonic acid ester can be reused as a raw material for the subsequent reaction.
Further, the other component containing the above-mentioned by-produced carboxylic acid ester recovered can be reused as a raw material for the first-stage reaction. Therefore, the raw material carboxylic acid ester is not substantially consumed.

The bottom liquid containing the produced carbonic acid ester is continuously withdrawn from the reaction system as a bottom liquid from the continuous multistage distillation column 32. That is, the target ester carbonate is continuously taken out of the reaction system as bottoms. When the catalyst is a homogeneous catalyst, a known method such as distillation is used to easily separate and recover the catalyst from the bottom liquid. The recovered catalyst is supplied to the continuous multistage distillation column 31 to be again used for the reaction.

By carrying out the above-mentioned reaction operation, carbonate ester can be produced efficiently and continuously.
When the boiling point of the raw material carbonic acid ester is higher than the boiling point of the by-produced carboxylic acid ester produced as a by-product, the reactor 33 may not be provided. In the case where a compound having a higher boiling point is continuously supplied to the upper stage of the continuous multistage distillation column 32 and a compound having a lower boiling point is continuously supplied to the lower stage among the carboxylic acid ester and the raw material carbonic acid ester, Reactor 33
Need not be provided. Furthermore, when different homogeneous catalysts are used for the first-stage reaction and the second-stage reaction, the continuous multi-stage distillation column 31
A distillation column may be connected in series between the reactor and the reactor 33. In this case, in the bottoms of the continuous multi-stage distillation column 31,
The catalyst used for the subsequent reaction is mixed via the conduit 34a.

The reactor having a multi-stage distillation column as a reactor is not limited to the configuration shown in FIG. 3 and can have various configurations. Next, an example of a method for producing a carbonic acid ester using a reactor having another configuration having a multistage distillation column will be described with reference to FIG. still,
For convenience of explanation, configurations having the same functions as those of the reactor (FIG. 3) are designated by the same reference numerals, and the description thereof will be omitted. In the following description, the case where the starting carboxylic acid ester has a boiling point lower than that of the aromatic hydroxy compound is taken as an example.

As shown in FIG. 4, the above-mentioned reactor is composed of a continuous multistage distillation column 41 as a reactor, a reboiler 4, a condenser 5, a pump 6 and the like.

In the continuous multi-stage distillation column 41, the raw material carboxylic acid ester and the aromatic hydroxy compound are subjected to gas-liquid contact while transesterifying, and the generated carboxylic acid ester and the raw material carbonic acid ester are transesterified to each other. Contact. Raw material supply pipes 8, 10, and 42 are connected to the continuous multistage distillation column 41. In the continuous multi-stage distillation column 41, the raw material supply pipe 8 is the raw material supply pipe 10
The raw material supply pipe 10 is connected to a higher stage than the raw material supply pipe 42. The raw material supply pipe 42 may be connected to the bottom of the tower.

The raw material supply pipe 8 continuously supplies the mixture containing the aromatic hydroxy compound to the continuous multistage distillation column 41. The raw material supply pipe 10 continuously supplies the mixture containing the raw material carboxylic acid ester to the continuous multistage distillation column 41. The raw material supply pipe 42 continuously supplies the mixture containing the raw material carbonic acid ester to the continuous multistage distillation column 41. If there is almost no difference between the boiling point of the raw material carboxylic acid ester and the boiling point of the aromatic hydroxy compound, one of the raw material supply pipes 8 and 10 may be omitted.

Further, the bottom of the continuous multistage distillation column 41 is connected to the reboiler 4 via the extraction pipe 11 and the conduit 43. Further, the top of the continuous multistage distillation column 41 is connected to the condenser 5 via the conduit 13. The outlet pipe 11 is branched so that a part of the bottom liquid can be continuously withdrawn as a bottom liquid out of the reaction system. The other structure of the reaction device is the same as that of the reaction device (FIG. 3).

Next, an example of a method for producing a carbonic acid ester using the reactor having the above structure will be described. For the sake of convenience of explanation, the explanation of the same operations as those in the reactor (FIG. 3) will be simplified.

First, the mixture containing the raw material carboxylic acid ester, the mixture containing the aromatic hydroxy compound, and the mixture containing the raw material carbonic acid ester are continuously fed to the continuous multistage distillation column 41 via the raw material supply pipes 8, 10 and 42. Supply to.

Then, the raw material carboxylic acid ester and aromatic hydroxy compound supplied to the continuous multi-stage distillation column 41 are subjected to gas-liquid contact, that is, reactive distillation while transesterifying in the presence of a catalyst. As a result, the first-stage reaction proceeds and carboxylic acid ester is produced. The carboxylic acid ester flows down in the continuous multi-stage distillation column 41. In addition, by-products such as alcohol are continuously withdrawn as a distillate. When the catalyst is a homogeneous catalyst, the catalyst is continuously supplied to the continuous multistage distillation column 41 together with the raw material carboxylic acid ester and / or the aromatic hydroxy compound. When the catalyst is a heterogeneous catalyst, the catalyst is held inside the continuous multistage distillation column 41. Further, when a solvent is used, the solvent may be continuously supplied to the continuous multistage distillation column 41 via the raw material supply pipe 42, but a solvent supply pipe may be separately provided.

Next, the produced carboxylic acid ester and the raw material carbonic acid ester fed to the continuous multistage distillation column 41 are subjected to gas-liquid contact while undergoing transesterification in the presence of a catalyst,
That is, it is reactively distilled. As a result, the second-stage reaction proceeds and carbonic acid ester is produced. The by-product carboxylic acid ester, which is a by-product, rises in the continuous multi-stage distillation column 41 and is used for the above-mentioned pre-stage reaction.

The bottom liquid containing the produced carbonic acid ester is continuously withdrawn from the reaction system as a bottom liquid from the continuous multistage distillation column 41. That is, the target ester carbonate is continuously taken out of the reaction system as bottoms. When the catalyst is a homogeneous catalyst, a known method such as distillation is used to easily separate and recover the catalyst from the bottom liquid.

By carrying out the above-mentioned reaction operation, carbonate ester can be efficiently and continuously produced.
The bottoms of the continuous multi-stage distillation column 41 may be supplied to another continuous multi-stage distillation column for gas-liquid contact while transesterifying. Thereby, the reaction efficiency (equilibrium conversion rate) can be further improved.

The reactor is not limited to the structure shown in FIGS. 1 to 4, but may have various structures.

As described above, the method for producing a carbonic acid ester according to the present invention comprises the raw material carboxylic acid ester represented by the general formula (1) and the aromatic hydroxy compound represented by the general formula (2). Is transesterified in the presence of a catalyst to produce the carboxylic acid ester represented by the general formula (3), and then the carboxylic acid ester and the starting carbonic acid represented by the general formula (4). By transesterification with an ester in the presence of a catalyst, a carbonate ester represented by the general formula (5) is produced.
Further, in the production method according to the present invention, the by-produced carboxylic acid ester represented by the general formula (6) which is by-produced together with the carbonic acid ester is recovered.

As a result, the equilibrium conversion rate can be improved and the carbonate ester can be efficiently produced.

Further, in the production method according to the present invention, the raw material carboxylic acid ester and the aromatic hydroxy compound are
In the presence of a catalyst, gas-liquid contact while transesterification,
The produced carboxylic acid ester is continuously withdrawn from the reaction system. Further, in the production method according to the present invention, the raw material carboxylic acid ester and the aromatic hydroxy compound are brought into gas-liquid contact while transesterifying in the presence of a catalyst, and alcohol as a by-product is continuously extracted from the reaction system. .

Further, in the production method according to the present invention, the carboxylic acid ester and the starting carbonic acid ester are brought into gas-liquid contact while transesterifying in the presence of a catalyst, and the resulting carbonic acid ester is continuously removed from the reaction system. Pull out. Further, in the production method according to the present invention, the carboxylic acid ester and the raw material carbonic acid ester are brought into gas-liquid contact while undergoing transesterification in the presence of a catalyst, and the by-produced carboxylic acid ester produced is continuously removed from the reaction system. Pull out.

As a result, the equilibrium conversion rate can be improved, and the carbonate ester can be efficiently and continuously produced.

[0121]

According to the above production method, R ¹ COOR ² in general formula (1) (1) (wherein R ¹ and R ² are each independently an alkyl group, an alicyclic hydrocarbon group or an aryl group) A raw material carboxylic acid ester represented by (representing an alkyl group) and a general formula (2) R ³ OH (2) (In the formula, R ³ represents an aromatic group which may have a substituent) By transesterifying with an aromatic hydroxy compound represented by the formula (3) R ¹ COOR ³ (3) (wherein R ¹ is an alkyl group or alicyclic carbon). A hydrogen group or an arylalkyl group, and R ³ represents an aromatic group which may have a substituent), and then a carboxylic acid ester represented by the formula (4) ) R ⁴ O-COOR ⁵ (4) (wherein R ⁴ and R ⁵ are respectively (Independently representing an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group) is transesterified with a raw material carbonic acid ester represented by the general formula (5) R ³ O—COOR. ⁶ (5) (In the formula, R ³ represents an aromatic group which may have a substituent, and R ⁶ represents a substituent selected from the group consisting of R ³ , R ⁴ and R ^5. The carbonic acid ester represented by

As a result, carbonate ester can be efficiently produced. The above-mentioned production method is excellent in safety because it does not use phosgene used in the conventional production method as a raw material. Further, the above manufacturing method does not use a raw material containing chlorine. Therefore, a high-quality polycarbonate can be obtained by using the obtained carbonic acid ester as a raw material.

[0123]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 Carbonic acid ester was produced using the reactor shown in FIG. However, as the batch reactor 1, a stainless reactor having an internal volume of 1 L equipped with a pressure reducing device was used. Also, the distillation column 2 has a height of 500 mm and an inner diameter.
1.5mmφ as packing in a 20mm stainless steel distillation column
The one filled with Dixon packing made of stainless steel was used.

The raw material supply pipe 10 is added to the batch reactor 1.
Through methyl valerate (raw material carboxylic acid ester) 3
00g, phenol (aromatic hydroxy compound) 100g,
And dibutyltin oxide "Bu ₂ SnO" as a catalyst
0.1g was charged.

Next, this reaction solution was heated to 240 ° C. with stirring, and the first-stage reaction was carried out at that temperature. At that time, the reflux ratio of the distillation column 2 was set to 2, and low boiling point components including by-products such as methanol (alcohol) were distilled off. The temperature of the batch reactor 1 was maintained at 240 ° C. by operating the pressure adjusting valve 16.

After carrying out the above first-stage reaction for 3 hours, most of unreacted methyl valerate and phenol were distilled off.
The total amount of methanol, methyl valerate and phenol distilled off was 302 g.

Subsequently, dimethyl carbonate (raw material ester carbonate) 1 was fed to the above batch reactor 1 through the raw material supply pipe 10.
I prepared 00g. Then close the batch reactor 1 and
The mixture was stirred at ℃ for 30 minutes, and the second-stage reaction was allowed to proceed until almost equilibrium was reached. Then, the pressure in the batch reactor 1 was reduced, and unreacted dimethyl carbonate was distilled off. Then, the mixture was stirred at 200 ° C. for 1 hour to further promote the second-stage reaction. At that time, the reflux ratio of the distillation column 2 was set to 2, and low boiling point components including by-products such as methyl valerate (carboxylic acid ester by-product) were distilled off.

After completion of the second-stage reaction, unreacted phenyl valerate (carboxylic acid ester) and the like were distilled off. This allows
53.7 g of a reaction mixture containing 95.5% by weight of diphenyl carbonate (carbonic acid ester) was obtained. The yield of diphenyl carbonate based on the substantially consumed phenol was 45.1 mol%.

As is clear from the above results, by carrying out the method according to this example, carbonate ester can be efficiently produced.

Example 2 Carbonic acid ester was continuously produced using the reaction apparatus shown in FIG. However, as the continuous multi-stage distillation column 31, a stainless distillation column having a height of 2.5 m and an inner diameter of 20 mm was filled with 1.5 mmφ stainless Dickson packing. Then, connect the raw material supply pipe 8 to a position 1 m below the tower top, and from the tower bottom
The raw material supply pipe 10 was connected to a position 500 mm above. Further, instead of heating the bottom liquid using the reboiler 4 or the like, the bottom part of the continuous multistage distillation column 31 was heated by a heater to supply the heat required for distillation.

Further, as the reactor 33, a stainless steel flow type reactor having a length of 200 mm and an inner diameter of 20 mm was used. Furthermore, the continuous multi-stage distillation column 32 has a height of 1.5 m and an inner diameter of 20.
A 1.5 mmφ stainless steel Dixon packing was used as a packing material in a mm stainless steel distillation column. Then, the conduit 36 was connected at a position 500 mm below the tower top. Further, instead of heating the bottom liquid using the reboiler 4 or the like, the bottom part of the continuous multistage distillation column 32 was heated by a heater to supply the heat required for distillation. still,
The continuous multi-stage distillation column 32 is equipped with a pressure reducing device.

Then, phenol (aromatic hydroxy compound) is fed to the continuous multi-stage distillation column 31 via the raw material supply pipe 8.
A supply liquid A composed of a raw material containing as a main component and titanium tetraphenoxide “Ti (OPh) ₄ ” as a catalyst was continuously supplied. Flow rate of supply liquid A per unit time is 24.7g / hr
And

Further, the feed liquid B (partly in gaseous form), which is a raw material containing methyl valerate (raw material carboxylic acid ester) as a main component, is continuously fed to the continuous multistage distillation column 31 through the raw material feed pipe 10. Supplied to. The flow rate of the supply liquid B per unit time was 58.8 g / hr. The titanium tetraphenoxide was added so that the amount of titanium added to the raw materials (the total amount of methyl valerate and phenol) was 500 ppm.

Regarding the operating conditions of the continuous multistage distillation column 31, the column bottom temperature was 243 ° C., the column top pressure was 4 kg / cm ² , and the reflux ratio was 2. Table 1 shows the above reaction conditions, that is, the flow rates and compositions of the feed liquid A and the feed liquid B, and the operating conditions of the continuous multistage distillation column 31.

In the continuous multi-stage distillation column 31 described above, methyl valerate and phenol were subjected to gas-liquid contact while transesterifying (pre-reaction). Then, the bottom liquid C containing the produced phenyl valerate (carboxylic acid ester) is fed to the reactor 33.
Continuously transferred to. The distillate D containing by-produced methanol (alcohol) was continuously taken out of the reaction system. The flow rate of the bottom liquid C per unit time is 75.0 g / hr, and the flow rate of the distillate D per unit time is 8.5.
It was g / hr.

Next, via the conduit 34a to the reactor 33,
The feed liquid E, which is a raw material containing dimethyl carbonate (raw carbonic acid ester) as a main component, was continuously fed. That is, the bottoms liquid C and the supply liquid E were continuously supplied to the reactor 33. The flow rate of the supply liquid E per unit time was 37.1 g / hr. Then, in the reactor 33, phenyl valerate and dimethyl carbonate were transesterified while being in gas-liquid contact (second-stage reaction). That is, in the reactor 33, the second-stage reaction was allowed to proceed until a nearly equilibrium state was reached. By operating the pressure adjusting valve 37, the pressure in the reactor 33 is adjusted to 10 kg / cm ² ,
That is, the vapor pressure of the reaction solution was adjusted to be equal to or higher than that, and the temperature of the reactor 33 was maintained at 200 ° C. Therefore, the reaction liquid in the reactor 33 is kept in the liquid phase state.

Then, the reaction solution in the reactor 33 was continuously transferred to the continuous multistage distillation column 32. The operating conditions of the continuous multi-stage distillation column 32 are that the bottom temperature is 219 ° C and the top pressure is 1
The reflux ratio was 00 mmHg and 1. Table 2 shows the above reaction conditions, that is, the flow rate and composition of the feed liquid E, and the operating conditions of the reactor 33 and the continuous multistage distillation column 32.

In the continuous multi-stage distillation column 32, phenyl valerate and dimethyl carbonate were subjected to gas-liquid contact while undergoing transesterification (second reaction). That is, the continuous multi-stage distillation column 32
Then, the latter-stage reaction was further advanced. Then, the bottom liquid F containing the produced diphenyl carbonate (carbonic acid ester) was continuously taken out of the reaction system. The distillate G containing by-produced methyl valerate (carboxylic acid ester by-product) and unreacted dimethyl carbonate and phenol was continuously taken out of the reaction system. The flow rate of the bottom liquid F per unit time was 28.1 g / hr, and the flow rate of the distillate G per unit time was 84.0 g / hr.

Then, the composition of the bottom product F was analyzed. As a result, the yield of diphenyl carbonate was 231 g / kg · hr when the raw materials (the total amount of methyl valerate, phenol and dimethyl carbonate) were supplied at a flow rate of 1 kg / hr. The yield of diphenyl carbonate based on the substantially consumed phenol was 99 mol%. Table 3 shows the above reaction results, that is, the flow rates and compositions of the distillate D and G and the bottoms C and F, and the yield and yield of diphenyl carbonate.
Shown in

By distilling the above distillate G, unreacted dimethyl carbonate and other components containing methyl valerate were separated. The above-mentioned dimethyl carbonate recovered is
It was fed again into the reactor 33 via the conduit 34a. Also,
The other components containing the above-mentioned recovered methyl valerate were supplied again to the continuous multistage distillation column 31 via the raw material supply pipe 10. Therefore, methyl valerate was not substantially consumed. Further, by distilling the bottom solution F, diphenyl carbonate and titanium tetraphenoxide were separated. The recovered titanium tetraphenoxide was supplied again to the continuous multistage distillation column 31 via the raw material supply pipe 8.

Example 3 Except that methyl valerate in Example 2 was changed to methyl butyrate (a raw material carboxylic acid ester), and titanium tetraphenoxide as a catalyst was changed to lead diphenoxide “Pb (OPh) ₂ ”. Example 2
Diphenyl carbonate was continuously produced using the same reactor. In addition, lead diphenoxide has a lead addition amount of 1000 p with respect to the raw materials (the total amount of methyl butyrate and phenol).
It was added so that it became pm.

The above reaction conditions, that is, the flow rates and compositions of the feed liquid A and the feed liquid B, and the continuous multistage distillation column 3
The operating conditions of No. 1 are shown in Table 1. Table 2 shows the flow rate and composition of the feed liquid E, and the operating conditions of the reactor 33 and the continuous multistage distillation column 32.

Then, the composition of the bottom liquid F was analyzed. As a result, the yield of diphenyl carbonate was 244 g / kg · hr.
The yield of diphenyl carbonate was 99 mol%. The above reaction results, namely distillate D and G and bottoms C and F
Table 3 shows the flow rates and the compositions of the above, and the yields and yields of diphenyl carbonate.

Example 4 Diphenyl carbonate was continuously produced using the same reaction apparatus as in Example 2 except that methyl valerate in Example 2 was changed to methyl hexanoate (raw material carboxylic acid ester). .

The above reaction conditions, that is, the flow rates and compositions of the feed liquid A and the feed liquid B, and the continuous multistage distillation column 3
The operating conditions of No. 1 are shown in Table 1. Table 2 shows the flow rate and composition of the feed liquid E, and the operating conditions of the reactor 33 and the continuous multistage distillation column 32.

Then, the composition of the bottom liquid F was analyzed. As a result, the yield of diphenyl carbonate was 189 g / kg · hr.
The yield of diphenyl carbonate was 91 mol%. The above reaction results, namely distillate D and G and bottoms C and F
Table 3 shows the flow rates and the compositions of the above, and the yields and yields of diphenyl carbonate.

[0148]

[Table 1]

[0149]

[Table 2]

[0150]

[Table 3]

As is clear from the results of Examples 2 to 4, it is understood that the carbonic acid ester can be efficiently and continuously produced by carrying out the method according to this Example.

[0152]

As described above, the method for producing a carbonic acid ester of the present invention has the general formula (1) R ¹ COOR ² (1) (wherein R ¹ and R ² are independently an alkyl group). , An alicyclic hydrocarbon group or an arylalkyl group), and a raw material carboxylic acid ester represented by the general formula (2) R ³ OH (2) (wherein R ³ has a substituent). An aromatic hydroxy compound represented by the formula (3) may be transesterified in the presence of a catalyst to give a compound represented by the general formula (3) R ¹ COOR ³ (3) ¹ represents an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group, and R ³ represents an aromatic group which may have a substituent). Carboxylic acid ester and the general formula (4) R ⁴ O—COOR ⁵ (4 ) (In the formula, R ⁴ and R ⁵ each independently represent an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group), and the ester carbonate is transesterified in the presence of a catalyst. By the general formula (5) R ³ O—COOR ⁶ (5) (wherein, R ³ represents an aromatic group which may have a substituent, R ⁶ is R ³ , R ⁴ and And a carbonic acid ester represented by the above (representing a substituent selected from the group consisting of R ⁵ ).

As a result, there is an effect that the carbonic acid ester can be efficiently produced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a reaction apparatus suitably used in a method for producing a carbonic acid ester in an example of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of another reaction apparatus suitably used in the method for producing a carbonic acid ester in one example of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of still another reaction apparatus suitably used in the method for producing a carbonate ester in one example of the present invention.

FIG. 4 is a block diagram showing a schematic configuration of still another reaction apparatus suitably used in the method for producing a carbonate ester in one example of the present invention.

[Explanation of symbols]

Single batch type reactor (reactor) 2 Distillation column 5 Condenser 8/10 Raw material supply pipe 11 Extraction pipe 21/22/23 Reactor 31/32 Continuous multistage distillation column (reactor, multistage distillation column) 33 Reactor 41 Continuous multi-stage distillation column (reactor, multi-stage distillation column)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Yoshida 14-1 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan Catalysis Function Development Laboratory

Claims (11)

[Claims] 1. A compound represented by the general formula (1) R ¹ COOR ² (1) (wherein R ¹ and R ² each independently represents an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group). Raw material carboxylic acid ester represented and aromatic represented by general formula (2) R ³ OH (2) (in the formula, R ³ represents an aromatic group which may have a substituent) By transesterification with a hydroxy compound in the presence of a catalyst, a compound represented by the general formula (3) R ¹ COOR ³ (3) (wherein R ¹ is an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group) And R ³ represents an aromatic group which may have a substituent), and then the carboxylic ester and the general formula (4) R ⁴ O—COOR ⁵ (4) (wherein R ⁴ and R ⁵ are each independently an alkyl group, A raw carbonic acid ester represented by an alicyclic hydrocarbon group or an arylalkyl group) is transesterified in the presence of a catalyst to give a compound of the general formula (5) R ³ O—COOR ⁶ (5) (In the formula, R ³ represents an aromatic group which may have a substituent, and R ⁶ represents a substituent selected from the group consisting of R ³ , R ⁴ and R ⁵ ) A method for producing a carbonic acid ester, which comprises producing a carbonic acid ester. 2. The method for producing a carbonate ester according to claim 1, wherein R ⁶ is R ³ . 3. A general formula by-produced together with the carbonic acid ester ^{(6) R 1 COOR 7 ......} (6) ( wherein, R ¹ represents an alkyl group, an alicyclic hydrocarbon group or an arylalkyl group, R ⁷ Is R ⁴ and R
^The method for producing a carbonic acid ester according to claim 1 or 2, wherein the by-produced carboxylic acid ester represented by the formula ( ⁵ ) represents a substituent selected from the group consisting of ⁵ ). 4. The method for producing a carbonic acid ester according to claim 3, wherein R ⁷ is equal to R ² . 5. The raw material carboxylic acid ester and the aromatic hydroxy compound are subjected to gas-liquid contact while transesterifying in the presence of a catalyst, and the produced carboxylic acid ester is continuously extracted from the reaction system. The method for producing the carbonic acid ester according to claim 1, wherein 6. The above-mentioned raw material carboxylic acid ester and an aromatic hydroxy compound are subjected to gas-liquid contact while transesterifying in the presence of a catalyst, and alcohol as a by-product is continuously extracted from the reaction system. The method for producing the carbonic acid ester according to any one of claims 1 to 5. 7. The carboxylic acid ester and the starting carbonic acid ester are brought into gas-liquid contact while transesterifying in the presence of a catalyst, and the resulting carbonic acid ester is continuously extracted from the reaction system. 7. The method for producing a carbonic acid ester according to any one of 1 to 6. 8. The carboxylic acid ester and the starting carbonic acid ester are subjected to gas-liquid contact while transesterifying in the presence of a catalyst, and the by-produced carboxylic acid ester produced as a by-product is continuously extracted from the reaction system. The method for producing a carbonic acid ester according to any one of claims 1 to 7. 9. The method for producing a carbonic acid ester according to claim 1, wherein the production of the carboxylic acid ester and the production of the carbonic acid ester are carried out in the same reactor. 10. The method for producing a carbonic acid ester according to claim 1, wherein the production of the carboxylic acid ester and / or the production of the carbonic acid ester are carried out in a multistage distillation column. 11. The method for producing a carbonate ester according to claim 1, wherein the production of the carboxylic acid ester and / or the production of the carbonic acid ester are performed in a bubble column.