KR102250750B1 - Method for preparing dimethyl terephthalate using acetylene - Google Patents

Abstract

The present invention relates to a method for preparing dimethyl terephthalate in a one-pot using an addition cyclization reaction using acetylene and dimethyl muconate, and the preparation method of the present invention is very simple and biologically-derived muconic acid And because acetylene derived from organisms can be used, it is not only eco-friendly, but also economical and efficient.

Description

Method for producing dimethyl terephthalate using acetylene {METHOD FOR PREPARING DIMETHYL TEREPHTHALATE USING ACETYLENE}

The present invention relates to a method for preparing dimethyl terephthalate using acetylene, and more specifically, dimethyl in one-pot using an addition cyclization reaction and dehydrogenation reaction using acetylene, dimethylmuconate, and a catalyst. It relates to a method for producing terephthalate.

An example of replacing petroleum-derived substances by using biologically-derived substances is biodiesel, which produces fuel that can be used for diesel engines through esterification of oils extracted from plants such as fluid oil, soybean oil, and palm oil. . In addition, biologically-derived materials are being actively studied in the traditional polymer industry as well as the substitution of the energy materials. Among them, polylactic acid, a biodegradable polymer produced from lactic acid as a raw material, is an example that has reached the stage of commercialization. A typical example is polytrimethylterephthalate (PTT) using (polylactic acid, PLA) and 1,3-propandiol.

Meanwhile, dimethyl terephthalate (hereinafter referred to as'DMT'), a representative raw material of polyester, is used as a major component of plastics, coatings, adhesives and paints, and it is reduced to synthesize various types of dialcohols, etc. It is used in several fields.

DMT uses a metal catalyst such as cobalt (Co) and manganese (Mn) in an acetic acid solution and a strong acid as a catalyst to oxidize with oxygen to prepare terephthalic acid (TPA), It is known to be obtained by esterification reaction of TPA and methanol prepared above, distillation under reduced pressure, and purification. DMT synthesized and purified in this way has a high purity of 99.99% or more, and can be used as a major raw material for polyester synthesis such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT). .

According to International Patent Publication No. WO 2012/082725, DMT can be manufactured using dimethyl muconate and ethylene as raw materials, and the manufacturing process goes through two steps, and because different solvents and catalysts are used for each step, the following There are the same fundamental weaknesses.

First, the reaction goes through several stages. If the process of making a single product goes through several steps, the investment cost increases, the design of the reaction becomes complicated and difficult, and the economic efficiency decreases. In addition, even if the yield of each step is high, the types and amounts of impurities increase as the steps go through several steps, and as a result, the yield and purity of the product decreases.

Second, since the reaction conditions in each step are very different and a highly corrosive material is used as a catalyst, high corrosion resistance is required for the material of the reactor, which increases the investment cost. In addition, the catalyst and solvent conditions of each step are different, and the reaction product of each step must be separated and purified for the progress of the reaction, which complicates the design of the process.

Lastly, because it is difficult to regenerate or has a large decrease in activity and uses an expensive catalyst, operability is poor and economical efficiency is low during product production.

Accordingly, the present inventors were studying a method for producing DMT using muconic acid, a material derived from organisms, as a raw material, and it was confirmed that DMT was produced with a high conversion rate when dimethyl muconate and acetylene were added cyclization reaction in the presence of a catalyst. The present invention has been completed.

International Patent Publication No. WO 2012/082725

Accordingly, it is an object of the present invention to provide a method for economically and efficiently producing DMT using a material derived from a living organism as a raw material.

In order to achieve the above object, the present invention,

Provides a method for producing dimethyl terephthalate (DMT) comprising the step of obtaining an addition cyclization reaction product and a dehydrogenation reaction product by introducing dimethylmuconate and acetylene gas into a reactor and reacting in a solvent in the presence of a catalyst do.

According to the present invention, the reaction step can be reduced by using acetylene in the synthesis process of DMT using dimethylmuconate, and the process design is easy and the investment cost is low, so it is economical by using an inexpensive catalyst that has a low economic burden of reuse. In addition, the method of the present invention can produce DMT having a high or equivalent level of purity in a high yield compared to the final material manufactured by the conventional method, thereby reducing production cost, and environmental problems by using raw materials derived from organisms. Can respond to. In addition, by using a catalyst, the addition cyclization reaction and dehydrogenation reaction can proceed in one-pot.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a method of preparing dimethyl terephthalate through an addition cyclization reaction step of dimethyl muconate and acetylene, and the method according to the present invention includes one less reaction step, and the use of an inexpensive metal catalyst. It is characterized.

Therefore, the manufacturing method of DMT according to the present invention is a conventional method (e.g., international Patent Publication No. WO 2012/082725), it is possible to produce high-purity DMT in an economical, efficient and high yield.

Accordingly, the present invention provides a method for preparing DMT comprising the step of adding dimethylmuconate and acetylene gas to a reactor and reacting in a solvent in the presence of a catalyst to obtain an addition cyclization reaction product and a dehydrogenation reaction product.

According to an embodiment, dimethylmuconate and acetylene gas are added to a reactor, the mixture is stirred in a solvent, and then the mixture is heated and heated to perform an addition cyclization reaction and a dehydrogenation reaction in one-pot. Can be manufactured.

The myuko dimethyl carbonate used as starting material in the production method of the present invention, DMT is trans, trans- may be myuko dimethyl carbonate (trans, trans -dimethylmuconate). The trans,trans-dimethylmuconate may be prepared from muconic acid in the presence of a catalyst in a solvent.

Examples of the solvent include alcohols such as methanol and ethanol; Polar solvents such as methyl iodide (MeI), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO); Alkyl ethers such as tetrahydrofuran (THF), diethyl ether, and dimethylethylene glycol; Alkyl acetates such as ethyl acetate and methyl acetate; Ketones such as methyl ethyl ketone (MEK) and acetone; Aromatic solvents such as benzene, toluene, xylene, chlorobenzene cresol, and methyl phenylester; Organic solvents such as methylene chloride and chloroform; And it may be selected from the group consisting of a mixture thereof, but is not limited thereto.

In addition, the catalyst may include acids such as methanesulfonic acid, p-paratoluenesulfonic acid, phosphoric acid, hydrochloric acid, and sulfuric acid; Bases such as potassium carbonate and sodium hydroxide; And it may be selected from the group consisting of a mixture thereof, but is not limited thereto.

In the present invention, the acetylene gas may be introduced at a pressure of 1 bar or more, 1 to 20 bar, preferably 3 to 20 bar, and more preferably 5 to 18 bar.

The addition cyclization and dehydrogenation reaction may be carried out at 100° C. or higher, 100° C. to 400° C., 110° C. to 400° C., 110° C. to 190° C., or 130° C. to 300° C., and the reaction time is 1 to 48 hours. , Preferably, it may be performed for 4 to 24 hours, but is not limited thereto.

The addition cyclization and dehydrogenation reaction may be performed in a solvent, and the solvent is, for example, an aromatic solvent such as benzene, toluene, chlorobenzene, cresol, methylphenylester and xylene, tetrahydrofuran and dimethylethylene glycol, and Alkyl ether solvents, alkyl acetate solvents such as methyl acetate, ethyl acetate and butyl acetate, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, N-methylpyrrolidone (NMP), dimethylformamide, dimethyl sulfoxide It may be an organic solvent selected from the group consisting of a side and a mixture thereof, but is not limited thereto. Preferably, it may be selected from the group consisting of metaxylene, tetrahydrofuran, ethyl acetate, dimethylethylene glycol, N-methylpyrrolidone, dimethyl sulfoxide, and mixtures thereof.

The solvent may be used in an amount of 1 to 200 equivalents, preferably 10 to 100 equivalents based on dimethyl muconate.

The dehydrogenation reaction is carried out in the presence of a catalyst, and the catalyst may be a metal halide, specifically, BeCl ₂ , MgCl ₂ , CaCl ₂ , SrCl ₂ , BaCl ₂ , BCl ₃ , AlCl ₃ , GaCl ₃ , InCl ₃ , In the group consisting of TiCl ₃ , TiCl ₄ , ZnCl ₂ , CrCl ₂ , CrCl ₃ , CrCl ₄ , FeCl ₂ , FeCl ₃ , FeCl ₄ , Fe ₂ Cl ₆ , CoCl ₂ , CoCl ₃ , CuCl ₂ , CuCl ₃ and mixtures thereof It may be selected, but is not limited thereto.

The metal halide catalyst may be used in an amount of 0.001 to 10 molar equivalents, 0.01 to 5 molar equivalents, 0.02 to 3 molar equivalents, 0.03 to 1 molar equivalents, or 0.05 to 0.2 molar equivalents based on dimethyl muconate.

After the addition cyclization reaction according to the preparation method of the present invention, dimethylcyclohexa-2,5-diene-1,4-dicarboxylate as an intermediate with DMT can be produced as an addition cyclization reaction product (see Example 2). .

Accordingly, the method of the present invention may further include a step of performing an aromatization reaction by heating the addition cyclization reactant, preferably dimethylcyclohexa-2,5-diene-1,4-dicarboxylate intermediate.

According to an embodiment, dimethylmuconate and acetylene gas are added to a reactor, the mixture is stirred in a catalyst and a solvent, heated and heated to obtain an addition cyclization reaction product, and then the addition cyclization reaction product is heated to aromatize. DMT can be produced by reacting.

In the aromatization reaction, an addition cyclization reaction product of dimethylmuconate and acetylene is added to the reactor and sealed at 100°C or higher, 100°C to 400°C, 110°C to 400°C, 110°C to 190°C, or 130°C to 300°C. It can be done by heating. The reaction time may be performed for 1 to 48 hours, preferably 4 to 24 hours, but is not limited thereto.

In the present invention, it is also possible to pressurize using an oxidizing agent during the aromatization reaction, and the oxidizing agent may be used without limitation if it is a component widely used in the art.

The oxidizing agent may be selected from the group consisting of, for example, hydrogen peroxide, perchloric acid, potassium permanganate, ozone, oxygen, and combinations thereof, and introducing a gas containing oxygen is convenient and economical, so it is preferable. The gas containing oxygen may be, for example, air, a mixed gas of oxygen and nitrogen, a mixed gas of oxygen and helium, a mixed gas of oxygen and an inert gas, or oxygen, but is not limited thereto.

In the aromatization reaction step, a solvent may be additionally used. At this time, the type of solvent is not particularly limited, and the solvent used in the addition cyclization reaction may be used, or other solvents may be used.

In the aromatization reaction, the addition cyclization reaction product can be used in the aromatization reaction without any special treatment, but it is preferable to perform the aromatization reaction after removing the acetylene gas used in the addition cyclization reaction by replacing it with air.

As described above, the manufacturing method of DMT according to the present invention is one reaction step in the presence of a catalyst, compared to the conventional method is very complex in commercial process design and the content of impurities is high through a reaction path of several steps. It is economical and easy to commercialize because it is possible to manufacture high-purity DMT with high yield. In addition, unlike DMT, which is commercially manufactured using PX derived from petroleum as a raw material, since it is manufactured using muconic acid, a material derived from organisms, as a raw material, it can be an eco-friendly and suitable alternative in the era of high oil prices.

[Example]

Hereinafter, the present invention will be described in more detail by the following examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.

Example 1: Synthesis of trans,trans-dimethylmuconate

Trans,trans-dimethylmuconate was synthesized according to the method described in Methods 1 to 3 below.

Method 1)

100 g of trans,trans-muconate was reacted with 5 g of concentrated sulfuric acid as a catalyst in 1,000 ml of methanol under reflux conditions to obtain 110 g of trans,trans-dimethylmuconate.

Method 2)

100 g of trans,trans-muconic acid was reacted with 5 g of p-toluenesulfonic acid as a catalyst in 1,000 ml of methanol under reflux conditions to obtain 111 g of trans,trans-dimethylmuconate.

Method 3)

Trans, trans-muconic acid 10 g was reacted with 300 mg of _{potassium carbonate (K 2} CO ₃ ) as a catalyst in 20 ml of a mixed solvent of MeI and DMF (1/3 (v/v)) at 40-50° C. 7.8 g of trans-dimethylmuconate was obtained.

The catalysts, solvents, and reaction temperature conditions used in Methods 1 to 3, and conversion rates to trans, trans-dimethylmuconate are shown in Table 1 below.

number catalyst menstruum Reaction temperature Conversion rate One Sulfuric acid Methanol reflux 91.7% 2 Paratoluenesulfonic acid Methanol reflux 92.0% 3 K ₂ CO ₃ MeI/DMF 40-50℃ 65.0%

As shown in Table 1, when paratoluenesulfonic acid was used as a catalyst, trans,trans-dimethylmuconate could be obtained with the highest conversion rate.

In addition, the thus prepared trans,trans-dimethylmuconate was cooled to room temperature and then filtered to crystallize. The trans,trans-dimethylmuconate prepared in Method 3 was added to 100 mL of methanol, crystallized, and filtered to obtain a high purity of 99.66%.

Comparative Example 1: addition cyclization reaction of trans,trans-dimethylmuconate and ethylene

The trans,trans-dimethylmuconate synthesized in Method 1 of Example 1 was subjected to an addition cyclization reaction with ethylene in a metaxylene (m-xylene) solvent.

Specifically, 18.1 g of the trans,trans-dimethylmuconate obtained in Method 1 of Example 1 was dissolved in 360 ml of a dimethylethylene glycol (DME) solvent to prepare a 0.3 M trans,trans-dimethylmuconate solution. Ethylene gas was pressurized to the prepared solution at a pressure of 17 bar, and an addition cyclization reaction was performed in a high-pressure reactor (Parr Reactor, 4533HP) at a reaction temperature of 150° C. for 16 hours. As a result, dimethylcyclohex-2-ene-1,4-dicarboxylate (intermediate 2, 15.5%) and a very small amount of DMT were obtained.

Comparative Example 2: addition cyclization reaction of trans,trans-dimethylmuconate and acetylene

The trans,trans-dimethylmuconate synthesized in Method 1 of Example 1 was subjected to an addition cyclization reaction with acetylene in a metaxylene solvent.

Specifically, 18.1 g of the trans,trans-dimethylmuconate obtained in Method 1 of Example 1 was dissolved in 360 ml of a dimethylethylene glycol (DME) solvent to prepare a 0.3 M trans,trans-dimethylmuconate solution. An acetylene gas was pressurized to the prepared solution at a pressure of 17 bar, and an addition cyclization reaction was performed in a high-pressure reactor (Parr Reactor, 4533HP) for 16 hours at a reaction temperature of 150°C. As a result, dimethylcyclohexa-2,5-diene-1,4-dicarboxylate (intermediate 1, 25.0%) and DMT (4.1%) were obtained.

Accordingly, it was confirmed that when dimethylmuconate and acetylene were reacted, the addition cyclization reaction and aromatization reaction were performed at once. Therefore, it can be seen that using acetylene is useful for manufacturing DMT in a simple and economical manner.

Example 2: addition cyclization reaction of trans,trans-dimethylmuconate and acetylene

In Comparative Example 2, the addition cyclization reaction was performed in the same manner as described in Comparative Example 2, except that 5 mol% _{of AlCl 3 was added relative to dimethyl muconate.}

Example 3: trans, trans- Dimethyl muconate and Addition cyclization reaction of acetylene

The addition cyclization reaction was carried out in the same manner as described in Example 2, except that _{AlCl 3} was changed to ZnCl _{2 in Example 2 above.}

Example 4: trans, trans- Dimethyl muconate and Addition cyclization reaction of acetylene

The addition cyclization reaction was carried out in the same manner as described in Example 2, except that _{AlCl 3} was changed to TiCl _{4 in Example 2 above.}

Test Example 1

The products obtained in Comparative Examples 1 and 2 and Examples 2 to 4 were subjected to gas chromatography, gas chromatography-mass spectrometry (GC-MS), liquid chromatography (HPLC), and nuclear magnetic resonance (NMR) according to the conditions described below. ) Analysis was performed, and the results are shown in Table 2 below.

1) Gas chromatography: quantitative analysis of substances, used as analysis data in the table below, model name (agilent's 6890A), FID detector, DB-5 column, 60 m x 0.32 mm x 1.0 μm

2) GC-MS: material qualitative analysis, molecular weight confirmation, model name (Perkin Elmer's Claus 680 GC and SQ 8 MS), DB-5 column, 15 m x 0.25 mm x 1.0 μm

3) HPLC: material purity analysis (qualitative analysis), model name (LC-10AD from Shimadzu), C-18 column, solvent conditions = acetonitrile: methanol = 4: 1 (v/v)

4) NMR analysis: material qualitative analysis, 600 MHz, CDCl ₃ solvent

Reaction conditions Reaction result Catalyst type Trans,trans-dimethylmuconate Intermediate 1 Intermediate 2 DMT Etc Comparative Example 1 - 76.8% - 15.5% <0.01% 7.7% Comparative Example 2 - 16.8% 55.4% - 7.1% 20.7% Example 2 AlCl ₃ 37.2% 28.4% - 26.6% 7.8% Example 3 ZnCl ₂ 31.8% 30.4% - 22.1% 15.7% Example 4 TiCl ₄ 26.4% 33.6% - 20.9% 19.1%

As shown in Table 2, it was confirmed that DMT conversion was performed at a higher ratio when acetylene was used than when ethylene was used for the addition cyclization reaction. When a metal halide catalyst was further used, the catalyst was not used. It was confirmed that DMT conversion was performed at a higher rate than the case.

Comparative Example 3: addition cyclization reaction of trans,trans-dimethylmuconic acid and acetylene

An addition cyclization reaction was performed in the same manner as described in Example 2, except that trans,trans-dimethylmuconic acid was used instead of trans,trans-dimethylmuconate, and proceeded in the absence of a metaxylene solvent. .

Comparative Example 4: addition cyclization reaction of trans,trans-dimethylmuconic acid and acetylene

An addition cyclization reaction was performed in the same manner as described in Example 2, except that trans,trans-dimethylmuconic acid was used instead of trans,trans-dimethylmuconate. As a result, cyclohex-2-ene-1,4-carboxylate (intermediate 3, 16.1%) and terephthalic acid (TPA) were obtained.

Comparative Example 5: addition cyclization reaction of trans,trans-dimethylmuconate and acetylene

The addition cyclization reaction was carried out in the same manner as described in Example 2, except that the metaxylene solvent was not present.

Test Example 2

The products obtained in Comparative Examples 3 to 5 were dissolved in tetrahydrofuran, and then analyzed in the same manner as described in Test Example 1, and the results are shown in Table 3 below.

Trans,trans-dimethylmuconic acid Trans,trans-dimethylmuconate Intermediate 3 Intermediate 1 TPA DMT Etc Comparative Example 3 30.2% - 0.1% - 0% - 69.7% Comparative Example 4 51.5% - 16.1% - 0.1% - 33.3% Comparative Example 5 - 5.7% - 34.8% - 1.1% 64.1%

As shown in Table 3, in Comparative Example 3, the addition cyclization reaction hardly proceeded, and about 70% of carbonized by-products were produced. In Comparative Example 4, although the addition cyclization reaction proceeded a little, only about 0.1% was converted to TPA, and in Comparative Example 5, most were carbonized by-products, and the generation of DMT hardly proceeded.

Examples 5 to 9: Addition cyclization reaction of trans,trans-dimethylmuconate and acetylene

Trans, trans-dimethyl in tetrahydrofuran (THF), ethyl acetate (EA), meta-xylene, N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO), respectively, instead of metaxylene solvent. An addition cyclization reaction was performed in the same manner as in Example 2, except that muconate was dissolved.

The products obtained in Examples 5 to 9 were analyzed in the same manner as described in Test Example 1, and the results are shown in Table 4 below.

menstruum Trans,trans-dimethylmuconate Intermediate 1 DMT Etc Example 5 THF 25.3% 24.5% 29.4% 20.8% Example 6 EA 29.1% 26.6% 25.8% 19.5% Example 7 meta-Xylene 32.5% 17.0% 35.1% 15.4% Example 8 NMP 27.8% 20.3% 29.0% 22.9% Example 9 DMSO 26.8% 23.7% 26.4% 23.1%

As shown in Table 4, trans, trans-dimethylmuconate was used in tetrahydrofuran (THF), ethyl acetate (EA), meta-xylene, N-methylpyrrolidone (NMP), and dimethyl sulfoxide. It was confirmed that when the addition cyclization reaction was performed in the presence of acetylene and a catalyst in an organic solvent such as (DMSO), it was converted to a high proportion of DMT. Accordingly, it was confirmed that when dimethylmuconate and acetylene were reacted in the presence of a catalyst, an addition cyclization reaction and a dehydrogenation reaction were performed at once. Therefore, it can be seen that using the above method is useful for manufacturing DMT in a simple and economical manner.

Claims (11)

Preparation of dimethylterephthalate (DMT), comprising the step of obtaining an addition cyclization reaction product and a dehydrogenation reaction product by introducing dimethylmuconate and acetylene gas into the reactor and reacting in a solvent in the presence of a catalyst Way.
The method of claim 1,
The method for producing dimethyl terephthalate, characterized in that the catalyst is a metal halide.
The method of claim 2,
The method for producing dimethyl terephthalate, characterized in that the metal halide catalyst is used in an amount of 0.001 to 10 molar equivalents based on dimethyl muconate.
The method of claim 1,
The method for producing dimethyl terephthalate, characterized in that the dimethyl muconate is trans, trans -dimethylmuconate (trans, trans-dimethylmuconate).
The method of claim 1,
The method for producing dimethyl terephthalate, characterized in that the acetylene gas is introduced at a pressure of 1 to 20 bar.
The method of claim 1,
A method for producing dimethyl terephthalate, characterized in that the reaction is carried out at 100°C to 400°C.
The method of claim 1,
A method for producing dimethyl terephthalate, characterized in that it further comprises the step of introducing the addition cyclization reaction product into a reactor and sealingly heated at 100°C to 400°C for aromatization reaction.
The method of claim 7,
A method for producing dimethyl terephthalate, characterized in that pressurization using a gas containing oxygen during the aromatization reaction.
The method of claim 7,
A method for producing dimethyl terephthalate, characterized in that the aromatization reaction is carried out after removing the acetylene gas by replacing it with air.
The method of claim 1,
The solvent is an organic solvent selected from the group consisting of aromatic solvents, alkyl ethers, alkyl acetates, ketones, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, and mixtures thereof, dimethyl terephthalate Manufacturing method.
The method of claim 1,
The method for producing dimethyl terephthalate, characterized in that the solvent is used in an amount of 1 to 200 equivalents based on dimethyl muconate.