A method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride

Abstract

The present invention provides a method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride, comprising the following steps: S1: adding fluorenone and N-alkylphthalimide to a solvent to obtain a mixed solution; S2: heating the mixed solution to a certain temperature, and dropping a catalyst acid, and stirring to heat the raw material reaction in the mixed solution to complete, to obtain a reaction solution; S3: adding the reaction solution to ice water, continuing the temperature reaction for a period of time, cooling, adding water, filtering, washing the filter cake with water, alkali washing, beating the solvent, filtering, and high-temperature vacuum drying to obtain 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride. A method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride according to the present invention, the preparation method according to the present invention is simple and fast, simple to operate, high in yield, and has the advantages of high purity of finished product.

Description

Technical Field

[0001] The invention belongs to the technical field of polyimide monomer raw material preparation, and in particular relates to a method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride. Background Art

[0002] 9,9-Bis(3,4-dicarboxyphenyl)fluorene dianhydride is the raw material of polyimide dianhydride monomer, and is used together with aromatic diamine to prepare polyimide film. Due to its outstanding performance, the application prospects of polyimide have been fully recognized, and it has been widely used in aviation, aerospace, microelectronics, nano, liquid crystal, separation membrane, laser and other fields.

[0003] At present, patent US05061809 reports a method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, which is divided into three steps: 9-fluorenone is used as a raw material and reacted with o-xylene under nitrogen protection and trifluoromethanesulfonic acid at 120°C for 2 days to obtain the intermediate tetramethyl compound with a yield of 66%. Secondly, the tetraacid is obtained by air oxidation under nitrogen protection with the catalysis of cobalt acetate tetrahydrate, manganese acetate tetrahydrate, sodium and propionic acid. Finally, the dianhydride is obtained by heating at 150°C for one day under a pressure of 0.5 torr.

[0004] The above method has the disadvantages of long reaction time and low yield, so it is necessary to develop a more efficient route to replace the existing technology. Summary of the invention

[0005] In view of this, the present invention aims to provide a method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride to solve the problems of long reaction time and low yield.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] Add fluorenone and N-alkylphthalimide to the ionic liquid, heat to 40°C, add the catalyst acid dropwise, stir and heat to 100°C until the raw materials react completely, then add the reaction solution to ice water, continue to heat to 100°C and react for 3 hours, cool, add water, filter, wash the filter cake with water, wash with alkali, beat with solvent, filter, and vacuum dry to obtain 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride. The above reaction route is:

[0008]

[0009] Furthermore, the alkyl group in the N-alkylphthalimide structure can be methyl, ethyl, propyl, phenyl, etc., and methyl is preferred.

[0010] Furthermore, the solvent is an ionic liquid, which can be: 1,3-dimethylimidazolium trifluoromethanesulfonate, 1,3-dimethylimidazolium methanesulfonate, 1,3-dimethylimidazolium hexafluorophosphate; 1,3-dimethylimidazolium p-toluenesulfonate, 1-ethyl-3-methylimidazolium perchlorate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium methanesulfonate, etc.; preferably 1,3-dimethylimidazolium methanesulfonate.

[0011] Furthermore, the catalyst acid is trifluoromethanesulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, sulfuric acid, perfluorosulfonic acid resin, preferably sulfuric acid.

[0012] Furthermore, the molar ratio of fluorenone, N-methylphthalimide and sulfuric acid is: 1:1:(1-4); preferably: 1:1:2.

[0013] Furthermore, the mass ratio of the fluorenone to the ionic liquid is 1:(3-6); preferably 1:4.

[0014] Furthermore, the reaction temperature is 80-120°C, preferably 100°C.

[0015] Compared with the prior art, the method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride described in the present invention has the following advantages:

[0016] The preparation method of the invention has the advantages of being simple, rapid, easy to operate, high in yield, and high in purity of the finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 This is a liquid chromatogram of 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride described in Example 1 of the present invention. DETAILED DESCRIPTION

[0019] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0020] The present invention will be described in detail below with reference to the embodiments and the accompanying drawings.

[0021] Example 1

[0022] 18g of fluorenone and 32.2g of N-methylphthalimide were added to 72g of 1,3-dimethylimidazole methanesulfonate ionic liquid, and then the temperature was raised to 40°C, 19g of sulfuric acid was added dropwise, and after stirring for 2 hours, the temperature was raised to 100°C and reacted for 4h. Then, the reaction solution was slowly added to 500ml of ice water to precipitate an off-white solid. After the addition was completed, the temperature was continued to rise to 100°C and reacted for 3 hours, and then the temperature was lowered, and 1000ml of water was added for filtration. The filter cake was washed three times with 100ml of water, and then rinsed with 100ml of 5% sodium carbonate solution. The obtained solid was added with 40ml of tertiary methyl ether for pulping, filtered, and vacuum dried at 170°C to obtain 39.2g of 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride, an off-white powder, with a yield of 89.58% and a content of 99.73% (liquid phase content see attached Figure 1 ).

[0023] Example 2

[0024] 18g of fluorenone and 32.2g of N-methylphthalimide were added to 72g of 1,3-dimethylimidazole methanesulfonate ionic liquid, and then the temperature was raised to 40°C, 22.5g of trifluoromethanesulfonic acid was added dropwise, and after stirring for 2 hours, the temperature was raised to 100°C and reacted for 4h. Then, the reaction solution was slowly added to 500ml of ice water to precipitate an off-white solid. After the addition was completed, the temperature was continued to rise to 100°C and reacted for 3 hours, then the temperature was lowered, and 1000ml of water was added for filtration. The filter cake was washed three times with 100ml of water, and then rinsed with 100ml of 5% sodium carbonate solution. 40ml of methyl tert-ether was added to the obtained solid for pulping, filtration, and vacuum drying at 170°C to obtain 25.1g of 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride, an off-white powder, with a yield of 54.8% and a liquid content of 98.21%.

[0025] Example 3

[0026] 18g of fluorenone and 32.2g of N-methylphthalimide were added to 86g of 1,3-dimethylimidazole toluenesulfonate ionic liquid, then the temperature was raised to 40°C, 34.4g of toluenesulfonic acid was added dropwise, and after stirring for 2 hours, the temperature was raised to 100°C and reacted for 4h. Then, the reaction solution was slowly added to 500ml of ice water to precipitate an off-white solid. After the addition was completed, the temperature was continued to rise to 100°C and reacted for 3 hours, then the temperature was lowered, and 1000ml of water was added for filtration. The filter cake was washed three times with 100ml of water, and then rinsed with 100ml of 5% sodium carbonate solution. 40ml of methyl tert-ether was added to the obtained solid for pulping, filtration, and vacuum drying at 170°C to obtain 15.6g of 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride, an off-white powder with a yield of 34.06% and a liquid content of 98.79%.

Claims

1. A method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride, Features: The steps include: S1: adding fluorenone and N-alkylphthalimide to a solvent to obtain a mixed solution; S2: heating the mixed solution to a certain temperature, adding a catalyst acid dropwise, stirring, and heating the mixed solution until the raw materials in the mixed solution react completely to obtain a reaction solution; S3: adding the reaction solution into ice water, continuing to heat the reaction for a period of time, cooling, adding water, filtering, washing the filter cake with water, washing with alkali, beating with solvent, filtering, and drying under high temperature and vacuum to obtain 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride; The alkyl group in the N-alkylphthalimide structure in step S1 is a methyl group; The solvent in step S1 is 1,3-dimethylimidazole methanesulfonate; The catalyst acid in step S2 is sulfuric acid; In step S2, the mixed solution is heated to 40°C.

2. A method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride according to claim 1, Features: The molar ratio of fluorenone, N-methylphthalimide and sulfuric acid is 1:1:(1-4).

3. A method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride according to claim 2, Features: The molar ratio of fluorenone, N-methylphthalimide and sulfuric acid is 1:1:

2.

4. A method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride according to claim 1, Features: The mass ratio of the fluorenone to the ionic liquid is 1:(3-6).

5. A method for preparing 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride according to claim 1, Features: The mass ratio of the fluorenone to the ionic liquid is 1:4.

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