KR20180078907A - Method for preparing aromatic dicarbonate - Google Patents

Abstract

The present invention relates to a method for producing an aromatic carbonate diester. The method comprises: a step of conducting a trans esterification reaction of an aliphatic carbonate diester and an aromatic alcohol in the presence of an organic metal catalyst to produce a reaction mixture; a step of isolating an aromatic carbonate diester and a carbonate reaction by-product containing the organic metal catalyst from the reaction mixture; a step of mixing the carbonate reaction by-product containing the organic metal catalyst with a polar solvent to produce a first reaction product in which the by-product is dissolved; a step of adding a non-polar solvent to the first reaction product to precipitate the organic metal catalyst; and a step of collecting the precipitated organic metal catalyst and introducing the same in the trans esterification reaction.

Description

METHOD FOR PREPARING AROMATIC DICARBONATE [0002]

The present invention relates to a process for producing aromatic carbonic acid diesters. More specifically, the present invention relates to a process for producing an aromatic carbonic acid diester capable of recovering a catalyst from a by-product produced in the production of an aromatic carbonic acid diester at a high yield.

Aromatic carbonic acid diester compounds are produced by using poisonous phosgene, but have a problem of using toxic phosgene, excessive alkali salts and organic solvents. A method for producing an aromatic carbonic acid diester compound by reacting an aliphatic carbonic acid diester compound with an aromatic alcohol in the presence of an organometallic catalyst has been developed in order to solve the problem caused by the production process of an aromatic carbonic acid diester compound using phosgene. The reaction between the aliphatic carbonic acid diester compound and the aromatic alcohol has a low equilibrium constant and can increase the productivity through the reactive distillation method in which the alcohol is removed as a byproduct under high temperature and high pressure conditions to improve the reaction. However, by-products are produced because the high-temperature reaction proceeds under the condition that the catalyst is present, and a part of the produced by-products is discarded to suppress the increase in the reaction system. In this process, some of the catalysts are also discarded. Catalyst disposal in the aromatic carbonic acid diester production process is not caused by the deactivation but occurs in the process of removing the byproducts. This is because of the loss of the material cost. When the catalyst in the waste is recovered and reused, It can be prevented that it is discarded as waste.

Since the by-products generated in the process have high boiling points, it is not easy to separate them from the catalyst by simple distillation or the like. Even if separation is possible, it requires a lot of energy at high temperature, and it is not suitable for synthesis of aromatic carbonic acid diester through aliphatic carbonic acid diester and aromatic alcohol having high energy consumption.

Another method for preventing the loss of the catalyst is a method of applying a heterogeneous catalyst comprising a catalyst supported on a metal oxide. In this case, since the catalyst is bonded to the metal oxide carrier, the amount of the catalyst incorporated into the by-product is extremely small, so that the content of the catalyst contained in the waste is extremely low even if the by-product is disposed of. When the catalyst is supported on the metal oxide, it can be applied through the new process or the improvement of the existing equipment, but it is more complicated and costly than the catalyst recovery process. A problem arises.

Related prior art is Japanese Patent Laid-Open No. 1997-169704.

An object of the present invention is to provide an aromatic carbonic acid diester production method capable of recovering a catalyst from the aromatic carbonic acid diester without recycling the by-product produced in the production of the aromatic carbonic acid diester and reusing it.

Another object of the present invention is to provide a method for producing an aromatic carbonic acid diester in which energy consumption is minimized without using a distillation method in the recovery of the catalyst.

It is still another object of the present invention to provide a process for producing an aromatic carbonic acid diester capable of recovering a catalyst used in the production of an aromatic carbonic acid diester at a high yield.

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

The present invention relates to a process for producing aromatic carbonic acid diesters. Said process comprising: transesterifying an aliphatic carbonic acid diester and an aromatic alcohol in the presence of an organometallic catalyst to produce a reaction mixture; Separating the carbonic reaction by-product containing the aromatic carbonic acid diester and the organometallic catalyst from the reaction mixture; Mixing a polar solvent in a carbonate reaction by-product containing the organometallic catalyst to produce a first reactant in which by-products are dissolved; Adding a nonpolar solvent to the first reactant to precipitate the organometallic catalyst; Recovering the precipitated organometallic catalyst and introducing it into the transesterification reaction; .

The polar solvent may include at least one of anisole, an aliphatic alcohol, an aromatic alcohol, a ketone, an aldehyde, a glycol, and a carbonate.

The nonpolar solvent may include at least one of pentane, hexane, heptane, octane, decane, dodecane, cyclopentane, cyclohexane, and cyclooctane.

In one embodiment, the polar solvent is anisole, and the nonpolar solvent may be hexane.

In another embodiment, the polar solvent is acetone and the nonpolar solvent may be cyclohexane.

In an embodiment, the polar solvent may be 50 to 500 parts by weight based on 100 parts by weight of the carbonate reaction by-product.

In an embodiment, the amount of the non-polar solvent may be 50 to 200 parts by weight based on 100 parts by weight of the polar solvent.

In an embodiment, the organometallic catalyst may include at least one of metals of Ti, Pb, Ce, Cu, Zn, Fe, Co, Ni, Al, V, Sm, Sn and Zr.

The organometallic catalyst may be an unsupported homogeneous catalyst.

The present invention can recover and reuse the catalyst without disposing the byproduct produced in the production of the aromatic carbonic acid diester, and it is possible to minimize the energy consumption without using the distillation system in the recovery of the catalyst, The present invention has the effect of providing an aromatic carbonic acid diester production method capable of recovering an aromatic carbonic acid diester.

1 is a process diagram showing a method for producing an aromatic carbonic acid diester according to one embodiment of the present invention.

The process for producing an aromatic carbonic acid diester according to the present invention comprises: transesterifying an aliphatic carbonic acid diester and an aromatic alcohol in the presence of an organometallic catalyst to prepare a reaction mixture; Separating the carbonic reaction by-product containing the aromatic carbonic acid diester and the organometallic catalyst from the reaction mixture; Mixing a polar solvent in a carbonate reaction by-product containing the organometallic catalyst to produce a first reactant in which by-products are dissolved; Adding a nonpolar solvent to the first reactant to precipitate the organometallic catalyst; Recovering the precipitated organometallic catalyst and introducing it into the transesterification reaction; .

1 is a process diagram showing a method for producing an aromatic carbonic acid diester according to one embodiment of the present invention.

Referring to FIG. 1, an aliphatic carbonic acid diester, an aromatic alcohol, and the like are introduced into the transesterification reactor (R1) through a line (L1). Although shown as one line L1 in the figure, they can be input through separate lines, respectively.

In the transesterification reactor (R1), an aliphatic carbonic acid diester and an aromatic alcohol are transesterified in the presence of an organometallic catalyst to prepare a reaction mixture.

The organometallic catalyst can be introduced via line L1, and then the recovered catalyst is introduced via line L5.

The aliphatic carbonic acid diester may be represented by the following formula (1).

[Chemical Formula 1]

In Formula 1, R ₁ is independently a substituted or unsubstituted C1 to C10 alkyl group or a C3 to C10 cycloalkyl group.

Specific examples of the aliphatic carbonic acid diester include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, dipentyl carbonate, dihexyl carbonate, diheptyl carbonate, dioctyl carbonate, dinonyl carbonate, didecyl carbonate, Di (methoxyethyl) carbonate, di (chloroethyl) carbonate, di (cyanoethyl) carbonate, and the like can be used.

Examples of the aromatic alcohol include phenol, cresol, xylenol, trimethylphenol, tetramethylphenol, ethylphenol, propylphenol, butylphenol, diethylphenol, methylethylphenol, methylpropylphenol, Various alkyl phenols such as phenol, hexyl phenol and cyclohexyl phenol, various alkoxy phenols such as methoxy phenol and ethoxy phenol, and aryl alkyl phenols such as phenyl propyl phenol.

The organometallic catalyst may include at least one of metals of Ti, Pb, Ce, Cu, Zn, Fe, Co, Ni, Al, V, Sm, Sn and Zr. In an embodiment, the organometallic catalyst is an unsupported homogeneous catalyst. Specifically, _{TiCl 4, Ti (OMe) 4} , (MeO) Ti (OPh) 3, (MeO) 2 Ti (OPh) 2, (MeO) 3 Ti (OPh), Ti (OPh) 4, Ti (= O) (acac) _2, comprise _{Pb (OPh) 2, FeCl 3} , Fe (OH) 3, Fe (OPh) 3, SnCl 4, Sn (OPh) 4, Bu 2 SnO, Bu 2 Sn (OPh) 2 , etc. And is not necessarily limited thereto.

The reaction mixture prepared by the transesterification reaction of the aliphatic carbonic acid diester and the aromatic alcohol is mixed with an aromatic carbonic acid diester and a by-product. The reaction mixture is discharged via line L2 and the product aromatic carbonic acid diester is discharged via line L4 and the by-product is not withdrawn via line L3 but recovered in the catalyst recovery reactor R2.

The byproduct is a carbonate reaction by-product containing an organometallic catalyst and contains an organometallic catalyst and an unreacted raw material, an aromatic alcohol, a carbonate derivative, a carbonyl acid, an ester, and the like.

A polar solvent is mixed and dissolved in a carbonate reaction by-product containing the organometallic catalyst to prepare a first reactant. Since the carbonate reaction by-product containing the organometallic catalyst contains a metal catalyst, which is a Lewis acid, and an aliphatic carbonate, aromatic carbonate, aromatic alcohol, carbonate derivative, carbonyl acid, ester, etc. having polarity, polar substances such as anisole, aliphatic alcohol , Aromatic alcohols, ketones, aldehydes, glycols, carbonates, etc., and can be dissolved well without forming precipitates.

In an embodiment, the polar solvent may be 50 to 500 parts by weight based on 100 parts by weight of the carbonate reaction by-product. The metal catalyst and the byproduct having a high viscosity are completely dissolved in the above composition, and the metal catalyst forms a precipitate even when the nonpolar solvent is used in a small amount. The byproduct can be maintained in a liquid state at room temperature to facilitate the catalyst separation through filtering.

The polar solvent is soluble both in the byproduct and in the organometallic catalyst and may include one or more of anisole, aliphatic alcohol, aromatic alcohol, ketone, aldehyde, glycol, carbonate.

Thereafter, a non-polar solvent is added to the first reactant to precipitate the organometallic catalyst. When a non-polar solvent is added to the first reactant having polarity, only the metal catalyst having a polarity forms a precipitate. Since aliphatic carbonates, aromatic carbonates, aromatic alcohols, carbonate derivatives, carbonylic acid, esters and the like, which are components of the byproduct, exist in a liquid state at a temperature of from room temperature to 100 ° C or lower, they are present as a liquid mixture even when a non- So that only the metal catalyst to be recovered can selectively precipitate. The non-polar solvent may be expensive to the organometallic catalyst, while it may be soluble for the by-products. For example, at least one of pentane, hexane, heptane, octane, decane, dodecane, cyclopentane, cyclohexane, and cyclooctane. The polarity of the solution is changed through the addition of the non-polar solvent, so that the residual by-product can be separated into the liquid phase and the catalyst can be separated into the solid phase and recovered as the solid phase catalyst.

In one embodiment, the polar solvent is anisole, and the nonpolar solvent may be hexane. Such a combination of a polar solvent and a non-polar solvent is advantageous in terms of excellent catalyst recovery rate, easy handling, and low cost.

In another embodiment, the polar solvent is acetone and the nonpolar solvent may be cyclohexane. Such a combination of a polar solvent and a non-polar solvent is advantageous in that the catalyst recovery rate is excellent.

In an embodiment, the amount of the non-polar solvent may be 50 to 200 parts by weight based on 100 parts by weight of the polar solvent. In the above range, only the metal catalyst selectively precipitates, and the organic by-products are dissolved.

1, the catalyst recovery reactor R2 is shown as a single reactor, but not limited thereto, and may be formed as a multi-stage reactor.

The organometallic catalyst precipitates and precipitates due to the difference in solubility, and then the organometallic catalyst and the remaining by-products are separated through filtration. The organometallic catalyst thus separated enters the transesterification reactor (R1) via line (L5) and participates in the synthesis of aromatic carbonic acid diester. The metal oxide of the organometallic catalyst is not left in the filtrate remaining after the filtration, and unreacted raw materials such as aliphatic carbonic acid diester and phenol are left in the filtrate when the diaryl carbonate is produced. Therefore, these unreacted raw materials can be recovered again and reused.

Hereinafter, the present invention will be described in more detail by way of examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Example

Example  1 to 6 and Comparative Example  1: catalyst recovery process

Example  One

5 g of a carbonate reaction by-product containing Ti (= O) (acac) ₂ and 5 g of anisole were mixed in a 50 mL flask and dissolved at room temperature. After confirming that the byproduct of the carbonate reaction was completely dissolved, 1 g of hexane was added to the solution and stirred for 1 hour. After stirring was completed, filtration was performed using a syringe filter having a pore size of 0.2 mu m.

Example  2

The procedure of Example 1 was repeated except that 3 g of hexane was added.

Example  3

Except that 5 g of hexane was added.

Example  4

The procedure of Example 1 was repeated except that 7 g of hexane was added.

Example  5

Except that 10 g of hexane was added.

Example  6

5 g of a carbonate reaction by-product containing Ti (= O) (acac) ₂ and 5 g of acetone were mixed in a 50 mL flask and dissolved at room temperature. After confirming that the byproduct of the carbonate reaction was completely dissolved, 5 g of cyclohexane was added to the solution, and the mixture was stirred for 1 hour. After stirring was completed, filtration was performed using a syringe filter having a pore size of 0.2 mu m.

Comparative Example  One

The procedure of Example 1 was repeated except that hexane was not added.

In Examples 1 to 6 and Comparative Example 1, catalyst concentrations before and after catalyst precipitation were analyzed using ICP-MS, respectively, and the results are shown in Table 1.

Comparative Example  2

5 g of a carbonate reaction by-product containing Ti (= O) (acac) ₂ and 5 g of methylene chloride were mixed in a 50 mL flask and dissolved at room temperature. After confirming that the byproduct of the carbonate reaction was completely dissolved, 5 g of toluene was added to the solution, and the mixture was stirred for 1 hour. After stirring was completed, filtration was performed using a syringe filter having a pore size of 0.2 mu m.

Example Comparative Example One 2 3 4 5 6 One 2 Raw material
input By-product input (g) 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 Ansol input (g) 5.0 5.0 5.0 5.0 5.0 - 5.0 - Amount of acetone (g) - - - - - 5.0 - - Hexane input (g) 1.0 3.0 5.0 7.0 10.0 - - 5.0 Cyclohexane input (g) 5.0 Methylene
Chloride
Input (g) - - - - - - - 5.0 toluene
Input (g) - - - - - - - 5.0 catalyst
density Before filtration (ppm) 3,455 2,923 2,533 2,235 1,900 2,533 3,800 2,533 After filtration (ppm) 3,094 2,108 1,576 1,214 764 1,601 3,649 2,508 Recovery rate (%) 10.44 27.88 37.79 45.69 59.79 36.79 3.97 1.00

As can be seen from the above Table 1, it can be confirmed that the catalyst recovery ratio of Example 1-6 is higher than that of Comparative Example 1-2.

Example  7

12.29 g of phenol, 5.88 g of dimethyl carbonate (DMC) and 20 ppm of the catalyst recovered in Example 1 were introduced into a 20 mL tubular SUS reactor and then sealed. The sealed tube reactor was placed in an oil bath maintained at a temperature of 235 ° C and shaken for 15 minutes. After removing the tube reactor and quenching it, 1 g of the sample was taken and diluted with Acetone (10 g) and internal standard solution (0.5 g), and the composition and yield were calculated using GC (7890A Gas chromatography, Agilent).

Example  8

The procedure of Example 7 was repeated, except that 30 ppm of the catalyst recovered in Example 1 was added.

Example  9

The procedure of Example 7 was repeated except that 40 ppm of the catalyst recovered in Example 1 was added.

Control Example  One

Except that 20 ppm of a fresh Ti (= O) (acac) ₂ catalyst instead of the recovered catalyst was added.

Control Example  2

The procedure of Example 7 was repeated, except that 30 ppm of a fresh Ti (= O) (acac) ₂ catalyst instead of the recovered catalyst was added.

Control Example  3

Fresh Ti (= O) (acac) ₂ catalyst, which is not the recovered catalyst Was added in an amount of 40 ppm.

Example 7 Example 8 Example 9 Control Example 1 Control Example 2 Control Example 3 Raw material
input Phenol input (g) 12.29 12.29 12.29 12.29 12.29 12.29 DMC input (g) 5.88 5.88 5.88 5.88 5.88 5.88 catalyst
density Recovery catalyst
(ppm) 20 30 40 - - - Fresh catalyst
(ppm) - - - 20 30 40 Reaction temperature (캜) 235 235 235 235 235 235 Reaction time (min) 15 15 15 15 15 15 MPC yield (%) 4.15 6.56 7.94 4.27 6.39 7.90

As shown in Table 2, the aromatic carbonic acid diester of the present invention had a yield of aromatic carbonic acid diester similar to or higher than that of Control Example 1-3 in which the fresh catalyst was applied, even though the recovered catalyst was applied, .

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (9)

Transesterifying an aliphatic carbonic acid diester and an aromatic alcohol in the presence of an organometallic catalyst to prepare a reaction mixture;
Separating the carbonic reaction by-product containing the aromatic carbonic acid diester and the organometallic catalyst from the reaction mixture;
Mixing a polar solvent in a carbonate reaction by-product containing the organometallic catalyst to produce a first reactant in which by-products are dissolved;
Adding a nonpolar solvent to the first reactant to precipitate the organometallic catalyst; And
Recovering the precipitated organometallic catalyst and introducing it into the transesterification reaction;
Lt; RTI ID = 0.0 > dicarboxylic < / RTI >

The method of claim 1, wherein the polar solvent comprises at least one of anisole, aliphatic alcohol, aromatic alcohol, ketone, aldehyde, glycol, and carbonate.
The aromatic carbonic acid diester according to claim 1, wherein the non-polar solvent comprises at least one of pentane, hexane, heptane, octane, decane, dodecane, cyclopentane, cyclohexane and cyclooctane.
The method of claim 1, wherein the polar solvent is anisole and the nonpolar solvent is hexane.
The process for producing an aromatic carbonic acid diester according to claim 1, wherein the polar solvent is acetone and the nonpolar solvent is cyclohexane.
The aromatic polycarbonate diester according to claim 1, wherein the polar solvent is 50 to 500 parts by weight based on 100 parts by weight of the carbonate reaction by-product.
The aromatic polycarbonate diester according to claim 1, wherein the non-polar solvent is 50 to 200 parts by weight based on 100 parts by weight of the polar solvent.
The method of claim 1, wherein the organometallic catalyst comprises at least one of metals of Ti, Pb, Ce, Cu, Zn, Fe, Co, Ni, Al, V, Sm, Sn, A method for producing an aromatic carbonic acid diester.
The method for producing aromatic carbonic acid diester according to claim 1, wherein the organometallic catalyst is a non-supported homogeneous catalyst.

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