Synthesis method of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride

Abstract

The present invention discloses a method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride. In the present invention, the synthesis of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride uses 3,3',4,4'-tetramethyldibenzophenone and 2-bromobiphenyl as raw materials, and is prepared through steps such as Grignard coupling reaction, dehydration and ring closure, oxidation, and anhydride formation. This application selects a brand-new process route, expanding the choice of raw materials; moreover, the raw materials of the process route are easily available, with good selectivity and high yield, and the overall yield reaches about 80%; in addition, the process in this application does not require special reaction equipment, can realize industrial batch production, and the HPLC content can reach more than 99.8%.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of organic compounds, and particularly relates to a method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride. Background Art

[0002] Since the research on separation membranes began in the 1970s, almost all polymer materials have been used in the manufacture of separation membranes. When using common polymer materials to prepare separation membranes, there are often situations where the permeability coefficient is high but the selectivity coefficient is low, or the selectivity coefficient is high but the permeability coefficient is low. However, the separation membranes prepared from polyimide materials can have both permeability and selectivity.

[0003] Due to the diverse structures, good thermal stability, strong mechanical properties, high tolerance to solvents and other chemical substances, and good film-forming properties of polyimide materials, polyimide has become an excellent material for separation membranes. For different separation objects and more separation membrane application environments, higher performance requirements are put forward for polyimide separation membrane materials. Therefore, the design and synthesis of high-performance polyimide monomer structures have become the research direction.

[0004] A class of polyimide monomers containing fluorene aromatic dianhydrides with rigid structures is applied to the manufacture of polyimide separation membranes, which can effectively improve the selectivity and permeability of separation membrane materials. At present, this type of polyimide separation membrane has been widely used in the production of separation membranes for separating multi-component liquids and gases. See related patents US3822202, US4705540, and US4717393.

[0005] As an important monomer of polyimide containing fluorene aromatic dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride has only been reported in the synthesis in US Patent US5061809. In the patent, 9-fluorenone and o-xylene are used as raw materials, and through catalytic coupling, oxidation, and anhydride formation, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride is obtained. The yield of the process route in the patent does not exceed 50%, and the product purity is not clearly defined. At the same time, there are no other synthesis methods and related patent reports on 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in China. Summary of the Invention

[0006] In view of the above-mentioned prior art, the present invention provides a method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride to solve the problems of single synthesis route and few optional raw materials for the polyimide monomer 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is to provide a method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, which includes the following steps:

[0008] S1: Co - dissolve magnesium powder, iodine and 2 - bromobiphenyl in a first solvent, and react at 60 - 65 °C for 1 - 2 h to obtain a Grignard reagent solution of 2 - bromobiphenyl;

[0009] S2: Dissolve 3,3',4,4' - tetramethyldibenzophenone in the first solvent, then drop the resulting solution into the Grignard reagent solution of 2 - bromobiphenyl cooled to room temperature, react at 20 - 30 °C for 1 - 2 h, then acidify and extract with dichloroethane in sequence to obtain a dichloroethane solution of [1,1' - biphenyl] - 2 - yl bis(3,4 - dimethylphenyl)methanol;

[0010] S3: Add a dehydrating agent to the dichloroethane solution of [1,1' - biphenyl] - 2 - yl bis(3,4 - dimethylphenyl)methanol, react at 70 - 80 °C for 3 - 5 h, then wash with water, concentrate and crystallize in sequence to obtain 9,9 - bis(3,4 - dimethylphenyl) - 9H - fluorene;

[0011] S4: Dissolve 9,9 - bis(3,4 - dimethylphenyl) - 9H - fluorene in a second solvent, add an oxidizing agent in batches under stirring conditions, then react at 70 - 90 °C for 3 - 5 h, then acidify, wash with water and dry in sequence to obtain 4,4' - (9H - fluorene - 9,9 - diyl)diphthalic acid;

[0012] S5: Disperse 4,4' - (9H - fluorene - 9,9 - diyl)diphthalic acid in o - xylene, reflux and separate water at 130 - 145 °C until no more water is separated, keep the temperature for reaction for 1.5 - 2.5 h, then crystallize, decolorize and recrystallize in sequence to obtain 9,9 - bis(3,4 - dicarboxyphenyl)fluorenedianhydride.

[0013] Based on the above - mentioned technical solution, the present invention can be further improved as follows.

[0014] Further, the first solvent is tetrahydrofuran.

[0015] Further, the mass ratio of magnesium powder, iodine to 2 - bromobiphenyl in S1 is 6 - 10:0.05 - 0.2:51 - 61.

[0016] Further, the mass ratio of 3,3',4,4' - tetramethyldibenzophenone added in S2 to 2 - bromobiphenyl is 47 - 48:51 - 61.

[0017] Further, the mass ratio of the trifluoromethanesulfonic acid added to the theoretical mass of [1,1' - biphenyl] - 2 - yl bis(3,4 - dimethylphenyl)methanol in the dichloroethane solution of [1,1' - biphenyl] - 2 - yl bis(3,4 - dimethylphenyl)methanol is 45 - 60:78 - 80.

[0018] Further, the second solvent is a mixed solution of pyridine and water, and the mass fraction of pyridine in the mixed solution is 50%.

[0019] Further, the oxidant is potassium permanganate.

[0020] Further, the mass ratio of potassium permanganate to 9,9-bis(3,4-dimethylphenyl)-9H-fluorene is 250-315:66-67; potassium permanganate is added in 8-12 times.

[0021] The beneficial effects of the present invention are as follows: In the present invention, the synthesis of 9,9-bis(3,4-dicarboxyphenyl)fluorenedianhydride is prepared from 3,3',4,4'-tetramethyldibenzophenone and 2-bromobiphenyl as raw materials through steps such as Grignard coupling reaction, dehydration and ring closure, oxidation, and anhydride formation. The synthesis process in this application has the following advantages:

[0022] 1. A new process route is selected, expanding the choice of raw materials;

[0023] 2. The raw materials of the process route are easily available, with good selectivity and high yield, and the overall yield reaches about 80%;

[0024] 3. No special reaction equipment is required, and industrial batch production can be realized, and the HPLC content can reach more than 99.8%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the 1H NMR spectrum of the intermediate [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol;

[0026] Figure 2 is the 1H NMR spectrum of the intermediate 9,9-bis(3,4-dimethylphenyl)-9H-fluorene;

[0027] Figure 3 is the 1H NMR spectrum of the intermediate 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid;

[0028] Figure 4 is the 1H NMR spectrum of the final product 9,9-bis(3,4-dicarboxyphenyl)fluorenedianhydride. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention discloses a method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorenedianhydride, and its synthesis route is as follows:

[0030]

[0031] The following is a detailed description of the specific embodiments of the present invention in conjunction with the examples.

[0032] Example 1

[0033] A method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, specifically comprising the following steps:

[0034] (1) Under nitrogen protection, add 7.5 g of magnesium powder to 50 ml of tetrahydrofuran, then add 0.1 g of iodine, control the system temperature at 65 °C, add 2.0 g of 2-bromobiphenyl, and start stirring; after the reaction is initiated, keep the reaction system at 65 °C, and dropwise add a mixed solution of 53.9 g of 2-bromobiphenyl and 215.6 g of tetrahydrofuran. After the addition is complete, keep the temperature at 65 °C and react for 1 h to obtain a Grignard reagent solution of 2-bromobiphenyl.

[0035] (2) Dissolve 47.7 g of 3,3',4,4'-tetramethyldibenzophenone in 143.1 g of tetrahydrofuran for later use; cool the Grignard reagent solution of 2-bromobiphenyl prepared in step (1) to 25 °C, and then dropwise add the prepared 3,3',4,4'-tetramethyldibenzophenone solution to the Grignard reagent solution, controlling the system temperature at 25 °C during the addition process; after the addition is complete, control the temperature of the reaction system at 25 °C and react at this temperature for 2 h; after the reaction is complete, acidify the reaction solution and extract it with dichloroethane to obtain a dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol. The theoretical content of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol in this solution is 78.5 g, the yield is calculated as 100%, and the HPLC content is 95.2%; the nuclear magnetic resonance hydrogen spectrum of the obtained product is as Figure 1 shown.

[0036] (3) Add 54 g of trifluoromethanesulfonic acid to the dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol obtained in step (2), then raise the temperature of the system to 70 °C and keep the temperature for 5 h; after the reaction is complete, wash the reaction solution with water, concentrate it, and crystallize it to obtain 68.4 g of 9,9-bis(3,4-dimethylphenyl)-9H-fluorene. After measurement, the yield is 91.3% and the HPLC content is 99.4%; the nuclear magnetic resonance hydrogen spectrum of the obtained product is as Figure 2 shown.

[0037] (4) Add 68.4 g of 9,9-bis(3,4-dimethylphenyl)-9H-fluorene to 547.2 g of a 50% aqueous pyridine solution, start stirring, control the temperature at 70 °C, and add 288.6 g of potassium permanganate in ten batches. After the addition is complete, keep the temperature for 5 h; after the reaction is complete, filter the reaction solution, acidify the filtrate, wash it with water, filter it, and dry it to obtain 84.2 g of 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid in the form of a white solid powder. After measurement, the yield is 93.2% and the HPLC content is 99.5%; the nuclear magnetic resonance hydrogen spectrum of the obtained product is as Figure 3 shown.

[0038] (5) 84.2 g of 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid was added to 336.8 g of o-xylene. Stirring was started, and the temperature was controlled at 130 °C for reflux and water separation. After basically no water was separated from the system, the reaction was continued to be carried out at the same temperature for 2.5 h. After the reaction was completed, the reaction solution was cooled, and after crystallization, decolorization, and secondary crystallization, it was dried to obtain 72.5 g of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in the form of a white solid. The yield was measured to be 92.9%, and the HPLC purity was 99.8%. The 1H NMR spectrum of the obtained product is as Figure 4 shown.

[0039] Example 2

[0040] A method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride specifically comprises the following steps:

[0041] (1) Under nitrogen protection, 6.3 g of magnesium powder was added to 50 ml of tetrahydrofuran, and then 0.1 g of iodine was added. The temperature of the system was controlled at 60 °C, and 2.0 g of 2-bromobiphenyl was added. Stirring was started. After the reaction was initiated, the reaction system was continuously maintained at 60 °C, and a mixed solution of 49.3 g of 2-bromobiphenyl and 197.5 g of tetrahydrofuran was added dropwise. After the addition was completed, the reaction was carried out at 60 °C for 2 h to obtain a Grignard reagent solution of 2-bromobiphenyl.

[0042] (2) 47.7 g of 3,3',4,4'-tetramethyldibenzophenone was dissolved in 143.1 g of tetrahydrofuran for use. The Grignard reagent solution of 2-bromobiphenyl prepared in step (1) was cooled to 20 °C, and then the prepared 3,3',4,4'-tetramethyldibenzophenone solution was added dropwise to the Grignard reagent solution. The temperature of the system was controlled at 20 °C during the addition process. After the addition was completed, the temperature of the reaction system was controlled at 20 °C, and the reaction was carried out at this temperature for 2 h. After the reaction was completed, the reaction solution was acidified and extracted with dichloroethane to obtain a dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol. The theoretical content of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol in this solution was 78.5 g, the yield was calculated as 100%, and the HPLC content was 94.6%.

[0043] (3) 45.0 g of trifluoromethanesulfonic acid was added to the dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol obtained in step (2), and then the temperature of the system was raised to 75 °C, and the reaction was carried out at this temperature for 4 h. After the reaction was completed, the reaction solution was washed with water, concentrated, and crystallized to obtain 66.1 g of 9,9-bis(3,4-dimethylphenyl)-9H-fluorene. The yield was measured to be 88.3%, and the HPLC content was 99.2%.

[0044] (4) Add 66.1 g of 9,9-bis(3,4-dimethylphenyl)-9H-fluorene to 528.8 g of an aqueous pyridine solution with a mass fraction of 50%. Start stirring and control the temperature at 80 °C. Add 251.0 g of potassium permanganate in ten batches. After the addition is complete, keep the temperature for reaction for 4 h. After the reaction is completed, filter the reaction solution. The filtrate is acidified, washed with water, filtered, and dried to obtain 78.8 g of 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid in the form of a white solid powder. The measured yield is 90.3%, and the HPLC content is 99.5%.

[0045] (5) Add 78.8 g of 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid to 236.4 g of o-xylene. Start stirring and reflux with water separation at 140 °C. When there is basically no water separated from the system, continue to keep the temperature for reaction for 2 h. After the reaction is completed, cool the reaction solution, and obtain 66.8 g of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in the form of a white solid through crystallization, decolorization, and secondary crystallization, followed by drying. The measured yield is 91.4%, and the HPCL purity is 99.8%.

[0046] Example 3

[0047] A method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride specifically includes the following steps:

[0048] (1) Under nitrogen protection, add 9.4 g of magnesium powder to 50 ml of tetrahydrofuran, then add 0.1 g of iodine, control the system temperature at 65 °C, add 2.0 g of 2-bromobiphenyl, and start stirring. After the reaction is initiated, keep the reaction system at 65 °C and dropwise add a mixed solution of 58.6 g of 2-bromobiphenyl and 234.4 g of tetrahydrofuran. After the addition is complete, keep the temperature at 65 °C for reaction for 2 h to obtain a Grignard reagent solution of 2-bromobiphenyl.

[0049] (2) Dissolve 47.7 g of 3,3',4,4'-tetramethyldibenzophenone in 143.1 g of tetrahydrofuran for use. Cool the Grignard reagent solution of 2-bromobiphenyl prepared in step (1) to 30 °C, and then dropwise add the prepared 3,3',4,4'-tetramethyldibenzophenone solution to the Grignard reagent solution, controlling the system temperature at 30 °C during the dropping process. After the addition is complete, control the temperature of the reaction system at 30 °C and react at this temperature for 1 h. After the reaction is completed, acidify the reaction solution and extract it with dichloroethane to obtain a dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol. The theoretical content of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol in this solution is 78.5 g, the yield is calculated as 100%, and the HPLC content is 93.2%.

[0050] (3) 60 g of trifluoromethanesulfonic acid was added to the dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol obtained in step (2), and then the temperature of the system was raised to 80 °C and the reaction was carried out for 3 h while maintaining the temperature; after the reaction was completed, the reaction solution was washed with water, concentrated, and crystallized to obtain 67.6 g of 9,9-bis(3,4-dimethylphenyl)-9H-fluorene. The yield was measured to be 90.3%, and the HPLC content was 99.3%.

[0051] (4) 67.6 g of 9,9-bis(3,4-dimethylphenyl)-9H-fluorene was added to 540.8 g of an aqueous pyridine solution with a mass fraction of 50%, stirring was started, the temperature was controlled at 90 °C, and 313.7 g of potassium permanganate was added in ten batches. After the addition was completed, the reaction was carried out for 3 h while maintaining the temperature; after the reaction was completed, the reaction solution was filtered, and the filtrate was acidified, washed with water, filtered, and dried to obtain 82.1 g of 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid in the form of a white solid powder. The yield was measured to be 91.9%, and the HPLC content was 99.5%.

[0052] (5) 82.1 g of 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid was added to 410.5 g of o-xylene, stirring was started, and the temperature was controlled at 145 °C for reflux and water separation. When basically no water was separated from the system, the reaction was continued for 1.5 h while maintaining the temperature; after the reaction was completed, the reaction solution was cooled, and after crystallization, decolorization, and secondary crystallization, it was dried to obtain 69.3 g of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in the form of a white solid. The yield was measured to be 91.1%, and the HPCL purity was 99.8%.

[0053] Although the specific embodiments of the present invention have been described in detail in combination with the embodiments, it should not be construed as a limitation on the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative labor still fall within the protection scope of this patent.

Claims

1. A method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, characterized in that, it comprises the following steps: S1: Dissolve magnesium powder, iodine and 2-bromobiphenyl in a first solvent, and react at 60-65°C for 1-2 h to obtain a Grignard reagent solution of 2-bromobiphenyl; the mass ratio of magnesium powder, iodine to 2-bromobiphenyl is 6-10:0.05-0.2:51-61; S2: Dissolve 3,3',4,4'-tetramethyldibenzophenone in the first solvent, and then drop the obtained solution into the Grignard reagent solution of 2-bromobiphenyl cooled to room temperature, react at 20-30°C for 1-2 h, and then acidify and extract with dichloroethane in sequence to obtain a dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol; the mass ratio of the added 3,3',4,4'-tetramethyldibenzophenone to 2-bromobiphenyl is 47-48:51-61; S3: Add a dehydrating agent to the dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol, react at 70-80°C for 3-5 h, and then wash with water, concentrate and crystallize in sequence to obtain 9,9-bis(3,4-dimethylphenyl)-9H-fluorene; the dehydrating agent is trifluoromethanesulfonic acid, and the mass ratio of the added trifluoromethanesulfonic acid to [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol in the dichloroethane solution of [1,1'-biphenyl]-2-ylbis(3,4-dimethylphenyl)methanol is 45-60:78-80; S4: Dissolve 9,9-bis(3,4-dimethylphenyl)-9H-fluorene in a second solvent, add an oxidizing agent in batches under stirring conditions, and then react at 70-90°C for 3-5 h, and then acidify, wash with water and dry in sequence to obtain 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid; the oxidizing agent is potassium permanganate, and the mass ratio of the potassium permanganate to 9,9-bis(3,4-dimethylphenyl)-9H-fluorene is 250-315:66-67; the potassium permanganate is added in 8-12 batches; S5: Disperse 4,4'-(9H-fluorene-9,9-diyl)diphthalic acid in o-xylene, reflux and separate water at 130-145°C until no water is separated, keep the temperature and react for 1.5-2.5 h, and then crystallize, decolorize and recrystallize in sequence to obtain 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride.

2. The method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride according to claim 1, characterized in that: the first solvent is tetrahydrofuran.

3. The method for synthesizing 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride according to claim 1, characterized in that: the second solvent is a mixed solution of pyridine and water, and the mass fraction of pyridine in the mixed solution is 50%.