A method for preparing 4-phenylacetylene phthalic anhydride

Abstract

This invention provides a method for preparing 4-phenylacetylene-based phthalic anhydride, comprising the following steps: phenylacetylene and phthalic anhydride undergo an oxidative coupling reaction in a solvent under the catalysis of a copper catalyst, tetramethylethylenediamine, and a base to obtain 4-phenylacetylene-based phthalic anhydride. The advantages of this invention are: This invention uses phenylacetylene and phthalic anhydride as main raw materials, and obtains 4-phenylacetylene-based phthalic anhydride through copper-catalyzed air oxidative coupling. The reaction steps are simple. The copper-catalyzed air oxidative coupling method used in this invention uses inexpensive raw materials, has higher selectivity, and a high reaction yield. Therefore, the preparation method described in this invention is novel, has a short reaction time, good selectivity, and low overall preparation cost with a high yield.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of synthesis of polyimide monomers, and particularly relates to a preparation method of 4-phenylethynyl phthalic anhydride. BACKGROUND

[0002] 4-phenylethynyl phthalic anhydride (PEPA) is an important polyimide capping agent. Polyimide (PI for short) is one of the best heat-resistant varieties in thermoplastic engineering plastics at present, is widely used in the fields of aviation, aerospace, electromechanical and electronics, and is known as one of the most promising engineering plastics in the 21st century. Since the mid-1970s, polyimide materials capped by ethynyl have been widely used. The imide oligomer of ethynyl generally undergoes polymerization and cross-linking through the ethynyl end group after being heated to 250 DEG C. In this process, no small molecules are released. However, there is a serious problem in the processing of polyimide capped by ethynyl. The melting point of the resin oligomer is relatively high, and polymerization begins immediately after melting, so that the processing window of the material is very narrow, the gel time at 195 DEG C is only a few minutes, and it is difficult to prepare large and complex parts, which limits the use of the material. Polyimide capped by phenylacetylene can overcome the narrow processing range of polyimide capped by ethynyl, and has good fluidity under harsh synthesis and processing conditions, and a wide processing range. Polyimide capped by phenylacetylene has excellent performance and good processing performance, and has been more and more widely used in the fields of aviation, aerospace, electronics and the like after more than 20 years of development, and is one of the current research hotspots of high-temperature-resistant polyimide materials. Therefore, it has high theoretical significance and practical application value to synthesize 4-phenylethynyl phthalic anhydride efficiently, simply and at low cost through molecular design.

[0003] The structural formula of 4-phenylethynyl phthalic anhydride is as follows:

[0004] At present, the method for synthesizing 4-phenylethynyl phthalic anhydride generally adopts 4-halophthalic anhydride or 4-halophthalic acid to couple with phenylacetylene under the catalysis of metal palladium, and then anhydride is formed. Since the palladium catalyst is expensive, the synthesis cost of 4-phenylethynyl phthalic anhydride is high. (Chinese patents CN103641806A, CN1257898C, CN101550122A, CN1603317A, American patent US2005215820A1) (Polymer, 1994, 35, 4857-4864; Journal of Chemical Research, 2012, 379-380; Cheinese Chemical Letters, 2011, 22, 159-162)

[0005] The raw material phthalic anhydride is much cheaper than 4-halophthalic anhydride or 4-halophthalic acid, and the price of copper catalyst is one thousandth of the price of palladium catalyst, so the use of phthalic anhydride as raw material, copper catalytic and oxidative coupling reaction of phenylacetylene can greatly reduce the synthesis cost of 4-phenylethynyl phthalic anhydride. SUMMARY

[0006] Therefore, the present application aims to provide a preparation method of 4-phenylethynyl phthalic anhydride, which has a simple synthesis route, improves product yield and reduces production cost.

[0007] To achieve the above-mentioned purposes, the technical scheme of the present application is as follows:

[0008] A preparation method of 4-phenylethynyl phthalic anhydride, comprising the following steps: phenylacetylene and phthalic anhydride are subjected to oxidative coupling reaction in a solvent under the catalysis of copper catalyst, tetramethyl ethylenediamine and base to obtain 4-phenylethynyl phthalic anhydride (I);

[0009]

[0010] Further, the copper catalyst includes one or more of copper chloride, copper oxalate, copper sulfate, copper bromide, copper iodide, copper acetate and copper nitrate.

[0011] Further, the base is an organic base.

[0012] Preferably, the base includes one or more of triethylamine, N,N-diisopropylethylamine, pyridine, N-methylmorpholine, 4-dimethylaminopyridine and 1,8-diazabicycloundec-7-ene.

[0013] Further, the molar ratio of phenylacetylene, phthalic anhydride, copper catalyst, tetramethyl ethylenediamine and base is 1:(1.2-3):(0.05-0.3):(0.1-0.6):(1.2-3).

[0014] Further, the solvent is an organic solvent.

[0015] Preferably, the organic solvent includes one or more of acetone, acetonitrile, tetrahydrofuran, ethyl acetate, 1,4-dioxane and toluene.

[0016] Further, the phenylacetylene and phthalic anhydride are subjected to oxidative coupling reaction in the solvent under the catalysis of copper catalyst, ligand tetramethyl ethylenediamine and base.

[0017] Further, the copper catalyst, ligand tetramethyl ethylenediamine and base are added to the solvent, and the phenylacetylene and phthalic anhydride are added under stirring, air is introduced, and the system is stirred at 38-42℃.

[0018] Preferably, the pressure after the air is introduced is kept at 0.8-1.2 MPa.

[0019] Preferably, the system is kept stirring at 38-42 DEG C for 11-13 h.

[0020] Compared with the prior art, the preparation method of the 4-phenylethynyl phthalic anhydride has the following advantages:

[0021] The present application uses phenylacetylene and phthalic anhydride as main raw materials, and 4-phenylethynyl phthalic anhydride is obtained through copper-catalyzed air oxidation coupling, and the reaction steps are simple, the copper-catalyzed air oxidation coupling method adopted in the present application has the advantages of low raw material price, high selectivity and high reaction yield, and therefore, the preparation method has the advantages of novelty, short reaction steps, good selectivity, low overall preparation cost and high yield. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and serve as an aid in explaining the illustrative embodiments of the present application and their descriptions, and do not constitute improper limitations on the present application. In the drawings:

[0023] Figure 1 The HPLC spectrum diagram of 4-phenylethynyl phthalic anhydride synthesized in the embodiments of the present application is shown in the figure;

[0024] Figure 2 The nuclear magnetic hydrogen spectrum diagram of the present application using deuterated chloroform as a solvent is shown in the figure. DETAILED DESCRIPTION

[0025] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0026] The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as generally understood by those skilled in the art to which the present application belongs. The test reagents used in the following embodiments, unless otherwise specified, are all conventional biochemical reagents; and the experimental methods, unless otherwise specified, are all conventional methods.

[0028] The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] The synthesis route of 4-phenylethynyl phthalic anhydride is as follows:

[0030]

[0031] Embodiment 1:

[0032] A method for preparing 4-phenylacetylene phthalic anhydride, comprising the following steps:

[0033] The molar ratio of phenylacetylene and phthalic anhydride is 1:1.2, copper chloride (6.58g, 0.05eq), tetramethyl ethylenediamine (11.38g, 0.1eq), triethylamine (118.9g, 1.2eq) and acetone (500mL) are added into a 5L high-pressure reactor, stirred uniformly, phenylacetylene (100g, 1eq) and phthalic anhydride (174.0g, 1.2eq) are added, sealed, filled with air to 1Mpa pressure in the kettle, heated at 40℃ for 12h. After HPLC detection, the reaction is completed, cooled, pressure relief, filtration, toluene recrystallization of the filter cake, drying, to obtain light yellow 4-phenylacetylene phthalic anhydride 223.6g, yield: 92.0%.

[0034] In the above reaction, in order to make the substrate phenylacetylene and phthalic anhydride fully contact and participate in the reaction, the solvent used should be selected as a polar organic solvent, therefore acetone can also be replaced by acetonitrile, tetrahydrofuran, ethyl acetate, 1,4-dioxane or toluene.

[0035] The organic base plays a role in alkaline environment, in order to ensure dissolution in organic solvent, commonly used organic bases can be selected, therefore triethylamine can also be replaced by N,N-diisopropyl ethylamine, pyridine, N-methyl morpholine, 4-dimethyl amino pyridine or 1,8-diazabicyclo (11.7) -ene.

[0036] The copper catalyst coordinates with the ligand tetramethyl ethylenediamine to play a role in catalyzing oxidative coupling, commonly used divalent copper salts can be selected, therefore copper chloride can also be replaced by copper oxalate, copper sulfate, copper bromide, copper iodide, copper acetate or copper nitrate.

[0037] Example 2:

[0038] A method for preparing 4-phenylacetylene phthalic anhydride, comprising the following steps:

[0039] The molar ratio of phenylacetylene and phthalic anhydride is 1:1.5, copper oxalate (14.84g, 0.1eq), tetramethyl ethylenediamine (22.76g, 0.2eq), N,N-diisopropyl ethylamine (189.8g, 1.5eq) and tetrahydrofuran (500mL) are added into a 5L high-pressure reactor, stirred uniformly, phenylacetylene (92.5g, 1eq) and phthalic anhydride (217.5g, 1.5eq) are added, filled with air to 1Mpa pressure in the kettle, heated at 40℃ for 12h. After HPLC detection, the reaction is completed, cooled, pressure relief, filtration, toluene recrystallization of the filter cake, drying, to obtain light yellow 4-phenylacetylene phthalic anhydride 239.9g, yield: 98.7%.

[0040] Example 3:

[0041] A method for preparing 4-phenylacetylene phthalic anhydride, comprising the following steps:

[0042] The molar ratio of phenylacetylene and phthalic anhydride is 1:2.0, copper sulfate anhydrous (23.44g, 0.15eq), tetramethyl ethylenediamine (34.13g, 0.3eq), pyridine (154.9g, 2.0eq) and acetonitrile (500mL) are added into a 5L high-pressure reactor, stirred uniformly, phenylacetylene (100g, 1eq) and phthalic anhydride (290.0g, 2eq) are added, the pressure in the reactor is filled with air to 1Mpa, and stirred at 40℃ for 12h. After the reaction is completed by HPLC detection, cooling, pressure relief, filtration, toluene recrystallization of the filter cake, drying, 234.3g of light yellow 4-phenylacetylene phthalic anhydride is obtained, the yield is 96.4%.

[0043] Example 4:

[0044] A method for preparing 4-phenylacetylene phthalic anhydride, comprising the following steps:

[0045] The molar ratio of phenylacetylene and phthalic anhydride is 1:2.4, copper acetate (35.57g, 0.2eq), tetramethyl ethylenediamine (45.51g, 0.4eq), N-methyl morpholine (237.7g, 2.4eq) and ethyl acetate (500mL) are added into a 5L high-pressure reactor, stirred uniformly, phenylacetylene (100g, 1eq) and phthalic anhydride (348.0g, 2.4eq) are added, the pressure in the reactor is filled with air to 1Mpa, and stirred at 40℃ for 12h. After the reaction is completed by HPLC detection, cooling, pressure relief, filtration, toluene recrystallization of the filter cake, drying, 231.6g of light yellow 4-phenylacetylene phthalic anhydride is obtained, the yield is 95.3%.

[0046] Example 5:

[0047] A method for preparing 4-phenylacetylene phthalic anhydride, comprising the following steps:

[0048] The molar ratio of phenylacetylene and phthalic anhydride is 1:2.8, copper nitrate (45.91g, 0.25eq), tetramethyl ethylenediamine (56.89g, 0.5eq), 4-dimethylamino pyridine (334.9g, 2.8eq) and toluene (500mL) are added into a 5L high-pressure reactor, stirred uniformly, phenylacetylene (100g, 1eq) and phthalic anhydride (406.1g, 2.8eq) are added, the pressure in the reactor is filled with air to 1Mpa, and stirred at 40℃ for 12h. After the reaction is completed by HPLC detection, cooling, pressure relief, filtration, toluene recrystallization of the filter cake, drying, 220.7g of light yellow 4-phenylacetylene phthalic anhydride is obtained, the yield is 90.8%.

[0049] Comparative Example 1

[0050] The molar ratio of phenylacetylene and phthalic anhydride was 1:1.5. Into a 5L high-pressure reactor, copper oxalate (14.84g, 0.1 eq), N,N-diisopropyl ethylamine (189.8g, 1.5 eq) and tetrahydrofuran (500mL) were added, and stirred uniformly. Then, phenylacetylene (92.5g, 1 eq) and phthalic anhydride (217.5g, 1.5 eq) were added. The pressure in the reactor was filled with air to 1Mpa, and stirred at 40°C for 12h. HPLC detection showed that 80% of the raw material phenylacetylene remained.

[0051] Comparative Example 2

[0052] The molar ratio of phenylacetylene and phthalic anhydride was 1:1.5. Into a 5L high-pressure reactor, copper oxalate (14.84g, 0.1 eq), N,N-diisopropyl ethylamine (189.8g, 1.5 eq) and tetrahydrofuran (500mL) were added, and stirred uniformly. Then, phenylacetylene (92.5g, 1 eq) and phthalic anhydride (217.5g, 1.5 eq) were added. The pressure in the reactor was filled with air to 1Mpa, and stirred at 40°C for 12h. HPLC detection showed that 80% of the raw material phenylacetylene remained.

[0053] Comparative Example 3

[0054] The molar ratio of phenylacetylene and phthalic anhydride was 1:1.5. Into a 5L high-pressure reactor, copper oxalate (14.84g, 0.1 eq), N,N-diisopropyl ethylamine (189.8g, 1.5 eq) and tetrahydrofuran (500mL) were added, and stirred uniformly. Then, phenylacetylene (92.5g, 1 eq) and phthalic anhydride (217.5g, 1.5 eq) were added. The pressure in the reactor was filled with air to 1Mpa, and stirred at 40°C for 12h. HPLC detection showed that 80% of the raw material phenylacetylene remained.

[0055] 4-Phenylacetylene phthalic anhydride was prepared according to the method described in Example 2. Phenylacetylene and phthalic anhydride were coupled and oxidized by air in the presence of a copper catalyst, a ligand tetramethyl ethylenediamine and an organic base to obtain 4-phenylacetylene phthalic anhydride. The HPLC spectrum of 4-phenylacetylene phthalic anhydride synthesized in this example is shown in Figure 1 Figure 2 The hydrogen spectrum shows that the product structure is correct.

[0056] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.​

Claims

1. A process for the preparation of 4-phenylacetylene phthalic anhydride, characterized by: The method comprises the following steps: phenylacetylene and phthalic anhydride are subjected to oxidative coupling reaction in a solvent under the catalysis of copper catalyst, tetramethyl ethylenediamine, and base to obtain 4-phenylacetylene phthalic anhydride; Phenylacetylene and phthalic anhydride are subjected to oxidative coupling reaction in a solvent under the catalysis of copper catalyst, tetramethyl ethylenediamine, and base; The copper catalyst, the ligand tetramethyl ethylenediamine, and the base are added to the solvent, and then phenylacetylene and phthalic anhydride are added under stirring, air is introduced, and the system is stirred at 38-42 DEG C.

2. The method for preparing 4-phenylethynyl phthalic anhydride according to claim 1, characterized in that: The copper catalyst comprises one or more of copper chloride, copper oxalate, copper sulfate, copper bromide, copper iodide, copper acetate, and copper nitrate.

3. The method for preparing 4-phenylethynyl phthalic anhydride according to claim 1, characterized in that: The base is an organic base.

4. The method for preparing 4-phenylethynyl phthalic anhydride according to claim 1, characterized in that: alkaline bases include triethylamine, N,N - diisopropylethylamine, pyridine, N - methylmorpholine, 4-dimethylaminopyridine, 1,8-diazabicycloundec-7-ene.

5. The method for preparing 4-phenylethynyl phthalic anhydride according to claim 1, characterized in that: The molar ratio of phenylacetylene, phthalic anhydride, copper catalyst, tetramethyl ethylenediamine, and base is 1:(1.2-3):(0.05-0.3):(0.1-0.6):(1.2-3).

6. The method for preparing 4-phenylethynyl phthalic anhydride according to claim 1, characterized in that: The solvent is an organic solvent.

7. The method for preparing 4-phenylethynyl phthalic anhydride according to claim 1, characterized in that: The solvent comprises one or more of acetone, acetonitrile, tetrahydrofuran, ethyl acetate, 1,4-dioxane, and toluene.

8. The method for preparing 4-phenylethynyl phthalic anhydride according to claim 1, characterized in that: After the air is introduced, the pressure is kept at 0.8-1.2 MPa.

9. The method for preparing 4-phenylethynyl phthalic anhydride according to claim 1, characterized in that: The system is stirred at 38-42 DEG C for 11-13 h.

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