Symmetrical ester group-containing aromatic dicarboxylic acid, polyarylester, and preparation method and application of symmetrical ester group-containing aromatic dicarboxylic acid and polyarylester

Abstract

The invention discloses a symmetrical ester-group-containing aromatic dicarboxylic acid monomer, polyarylester and a preparation method and application thereof, the symmetrical ester-group-containing aromatic dicarboxylic acid monomer is prepared from 4-formylbenzoic acid or a derivative thereof and aromatic ring-containing dihydric phenol through an esterification reaction and an aldehyde group oxidation reaction in sequence, and the symmetrical ester-group-containing aromatic dicarboxylic acid monomer is copolymerized with aromatic amine to form polyarylester. Polymerization is realized by constructing heteroaromatic rings, and polyarylester containing heteroaromatic rings in a main chain structure is obtained. The polyarylester is superior to a traditional polyarylester material, has good thermodynamic performance, optical performance, acid and alkali resistance, aging resistance and gas separation performance, and can be used in multiple fields of screens, battery diaphragms, gas separation membranes and the like after being formed into a film.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, in particular to a symmetrical ester-containing aromatic dicarboxylic acid monomer, a polyarylate and a preparation method and application thereof. BACKGROUND

[0002] Aromatic polyester (also known as polyarylate) is a special polymer with aromatic rings and ester bonds in the molecular backbone, which has high temperature resistance, high flame resistance, high strength, high modulus, good dimensional stability and radiation resistance, and is widely used in electronic appliances, aerospace, medical devices, 5G communication, automobiles, military and other fields. Polyarylate can be divided into crystalline polyarylate, liquid crystal polyarylate and amorphous polyarylate according to the aggregation state structure. Crystalline polyarylate has a high melting temperature and is difficult to process; liquid crystal polyarylate mainly refers to thermotropic liquid crystal polyarylate (TLCP), which forms a liquid crystal phase in the molten state; amorphous polyarylate has a main chain containing disordered links, asymmetric or large side groups, etc., which is not easy to crystallize and exhibits isotropy, and can be applied to high-performance optical transparent materials and other fields.

[0003] The existing polyarylate main chain is mainly composed of carbon and oxygen elements, and changing the monomer structure, introducing side groups or electronic effect groups is a common technical means to change the performance of polyarylate, but the performance improvement space is limited, and it still cannot meet the special needs of heat resistance, mechanical properties and optical properties of materials in the fields of aerospace, automobiles, electronic devices, etc. The existing polyarylate monomer types are relatively few, which cannot meet the needs of multifunctional polyarylate design. On the other hand, traditional polyarylate is polymerized by esterification reaction between monomers, which limits the molecular weight of polyarylate to some extent, and the high energy consumption of the polymerization process is not conducive to the polymerization reaction. SUMMARY

[0004] The purpose of the present application is to provide a symmetrical ester-containing aromatic dicarboxylic acid monomer and a preparation method thereof which solve the above technical problems.

[0005] The purpose of the present application is to provide a polyarylate prepared from the above-mentioned symmetrical ester-containing aromatic dicarboxylic acid monomer and a preparation method thereof.

[0006] The purpose of the present application is to provide a use of the above-mentioned polyarylate.

[0007] To this end, the technical solution of the present application is as follows:

[0008] A symmetrical ester-containing aromatic dicarboxylic acid monomer has the chemical structural formula:

[0009]

[0010] wherein the substituent R is selected from one of Cl, F, Br, CH3O, CH3, H, and n is the number of substituent R, which is 1, 2, 3 or 4; Ar is a group with aromatic ring structure, which is selected from:

[0011]

[0012] The symmetrical ester-containing aromatic dicarboxylic acid monomer is prepared from 4-aldehydebenzoic acid or its derivative and an aromatic ring-containing diphenol through esterification and aldehyde oxidation in sequence; wherein,

[0013] The chemical structural formula of 4-aldehydebenzoic acid or its derivative is:

[0014]

[0015] wherein X is chlorine or hydroxyl; the substituent R is selected from one of Cl, F, Br, CH3O, CH3, H, and R is located at any position on the benzene ring except the aldehyde group and -COX; n is the number of substituent R, which is 1, 2, 3 or 4.

[0016] The chemical structural formula of the aromatic ring-containing diphenol is:

[0017] HOAr-OH,

[0018] wherein Ar is a group with aromatic ring structure.

[0019] Preferably, the aromatic ring-containing diphenol is selected from:

[0020]

[0021] The chemical reaction route of the preparation process of the symmetrical ester-containing aromatic dicarboxylic acid monomer is shown as follows:

[0022]

[0023] Specifically, the preparation method of the symmetrical ester-containing aromatic dicarboxylic acid monomer is described as follows.

[0024] (1) 4-aldehydebenzoic acid or its derivative, the aromatic ring-containing diphenol and an activating agent are added into an aprotic polar organic solvent, and stirred at 10-45°C for 12-72h (preferably 12-48h); after the reaction is completed, the reaction product is sequentially subjected to water washing, dilute hydrochloric acid washing, alkali washing and recrystallization to prepare an ester-containing aromatic dialdehyde;

[0025] (2) the ester-containing aromatic dialdehyde and an oxidizing agent are added into a solvent, and stirred at 10-45°C for 6-48h; after the reaction is completed, the symmetrical ester-containing aromatic dicarboxylic acid is prepared through acidification, filtration and beating.

[0026] In step S1, the molar ratio of 4-aldehydo-benzoic acid or its derivative to the aromatic ring-containing dihydric phenol is preferably 1:(0.3-0.5).

[0027] In step S1, the specific selection of the activating agent is related to the chemical structure of 4-aldehydo-benzoic acid or its derivative: The chemical structure of X is related; specifically,

[0028] Case 1: when X is hydroxyl, the activating agent is a mixture of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and 4-dimethylaminopyridine (DMAP) in a molar ratio of 1:(0.1-2); or, the activating agent is a mixture of dicyclohexyl carbodiimide (DCC) and 4-dimethylaminopyridine (DMAP) in a molar ratio of 1:(0.1-2);

[0029] The amount of activating agent added is such that the molar ratio of 4-aldehydo-benzoic acid or its derivative to 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) or dicyclohexyl carbodiimide (DCC) in the activating agent is 1:(1-2);

[0030] Case 2: when X is chlorine, the activating agent is an organic base, preferably triethylamine or pyridine;

[0031] The amount of activating agent added is such that the molar ratio of 4-aldehydo-benzoic acid or its derivative to the organic base is 1:(1-1.5).

[0032] In the above step (1), the aprotic polar organic solvent is one of dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane; the amount of aprotic polar organic solvent is 10-30 times the weight of 4-aldehydo-benzoic acid or its derivative.

[0033] In the subsequent processing steps of the above step (1), the dilute hydrochloric acid washing uses a 0.2wt%-2wt% hydrochloric acid solution; the alkali washing uses a 1wt%-8wt% sodium bicarbonate solution or a 1wt%-20wt% sodium carbonate solution; the recrystallization uses one of N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, acetic acid or a mixture of two of them in any ratio.

[0034] In the above step (2), the oxidizing agent is sodium chlorite, and the molar amount of the ester-containing aromatic dialdehyde or its derivative to the oxidizing agent is 1:(2-5).

[0035] In the above step (2), the solvent is one of water, tert-butyl alcohol, acetone or a mixture of two of them in any ratio, and the amount is 10-20 times the amount of the ester-containing aromatic dialdehyde or its derivative.

[0036] In the step (2), the acid washing step uses dilute hydrochloric acid, which is a 0.1wt%-1wt% hydrochloric acid solution.

[0037] In the step (2), the beating-up solvent is one of N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, and acetic acid, or a mixture of two of them in any ratio.

[0038] In the step (2), the beating-up operation is as follows: the solid obtained by filtration is dispersed in the beating-up organic solvent, and then stirred at 40-80°C for 2-12h; after the stirring, the mixture is cooled to room temperature, filtered, and the obtained solid is dispersed in water, and then stirred at 15-35°C for 0.5-6h; after the stirring, the mixture is filtered, and the above water beating-up process is repeated for 3-6 times; wherein the amount of the beating-up organic solvent is 4-6 times the weight of the asymmetric ester-containing aromatic dialdehyde; and the amount of the water used for beating-up is 4-8 times the weight of the asymmetric ester-containing aromatic dialdehyde.

[0039] A polyarylate prepared from the above asymmetric ester-containing aromatic dicarboxylic acid monomer, and having the chemical structural formula:

[0040]

[0041] As described above, Ar is a group having an aromatic ring structure, and preferably has one of the following chemical structural formulas:

[0042]

[0043] has one of the following chemical structural formulas:

[0044]

[0045] m is the degree of substitution, and m=100-10000.

[0046] In some embodiments of the present application, the polyarylate has a number average molecular weight of 3.29-5.38 million Daltons and a dispersity of 1.97-2.45.

[0047] A preparation method of the above polyarylate, and the specific steps are as follows:

[0048] S1, the ester-containing dicarboxylic acid, aromatic amine and polyphosphoric acid are added into a reaction bottle, and the temperature is controlled at 160-200°C under nitrogen protection, and the reaction is carried out for 6-48h;

[0049] S2, the reaction liquid is washed with water at room temperature until the pH is 6-7, and the obtained solid is dried to obtain a polyarylate having an aromatic heterocyclic ring in the main chain.

[0050] In the above step S1, the aromatic amine is selected from the following chemical structure:

[0051]

[0052] In the above step S1, the molar ratio of the symmetrical ester-containing aromatic dicarboxylic acid and the aromatic amine is 1: (0.97-1.02), and the amount of the polyphosphoric acid is 8-20 times the weight of the symmetrical ester-containing aromatic dicarboxylic acid. In the above step S1, the polyphosphoric acid preferably contains ≥85wt% P2O5.

[0053] The use of the above polyarylate, specifically, after being formed into a film, is respectively:

[0054] 1) using its heat resistance, acid and alkali resistance as a substrate, battery separator;

[0055] 2) using its heat resistance and optical properties as an optical film on a color filter, printed matter, luminescent material, electronic device, flexible display screen, liquid crystal display device, and electronic paper;

[0056] 2) using its gas separation properties as a gas separation membrane to separate helium from air.

[0057] A method for preparing a gas separation membrane, the steps of which are: dissolving polyurethane in N,N-dimethylformamide to form a 20wt%-35wt% polymer solution; filtering through an organic filter membrane, vacuum drying and defoaming, then coating the solution on a clean glass plate and casting a film by the doctor blade method; then, placing the glass plate coated with the polymer solution in a vacuum drying oven at 60°C-90°C to remove the solvent, and then heating at 140°C-160°C for 1h-2h to obtain a polymer film.

[0058] Compared with the prior art, the present application designs a symmetrical ester-containing aromatic dicarboxylic acid, which is copolymerized with an aromatic amine to form a polyarylate. The polyarylate is different from traditional polymers formed by esterification reaction, and is formed by constructing an aromatic heterocycle. The polyarylate is a copolymer with an aromatic heterocycle in the main chain structure, and has electron transport performance, so it can exhibit good light-sensitive material properties. In addition, due to the presence of heteroatoms in the chemical structure of the copolymer, the intermolecular interaction force of the polyarylate is significantly enhanced, and the glass transition temperature reaches more than 300°C, which is significantly higher than that of existing polyarylate materials. At the same time, the acid and alkali resistance and anti-aging performance of the polyarylate are better than those of traditional polyarylate materials, so it can be used in the field of screens and battery separators after being formed into a film. The polyarylate also has good gas separation performance, so it can be used to separate helium from air after being formed into a film. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 NMR test chart of compound 3 prepared for Example 1 of the present application;

[0060] Figure 2 NMR test chart of compound 6 prepared for example 5 of the present application;

[0061] Figure 3 NMR test chart of compound 9 prepared for example 7 of the present application;

[0062] Figure 4 NMR test chart of compound 10 prepared for example 8 of the present application. DETAILED DESCRIPTION

[0063] The present application will be further described in conjunction with specific examples below, but the following examples by no means limit the present application in any aspect.

[0064] Example 1

[0065] Dissolve 30 g (0.2 mol) of compound 1 in 300 g of dichloromethane (DCM), then add 33.6 g (0.1 mol) of compound 2, and then add 38.34 g (0.2 mol) of EDC and 48.8 g (0.4 mol) of DMAP, stir at 10℃ for 12 h, TLC analysis shows that the reaction is complete, wash the reaction solution with water once, then wash with 0.2 wt% HCl once, and then wash with 1 wt% sodium bicarbonate once, concentrate the organic phase, and recrystallize the solid with acetic acid to obtain compound 3, with a yield of 92%.

[0066] NMR hydrogen spectrum data are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 10.16 (s, 2H), 8.37 (d, 4H, J = 8.4 Hz), 8.04 (d, 4H, J = 8.4 Hz), 7.52 (d, 4H, J = 8.8 Hz), 7.30 (d, 4H, J = 8.8 Hz), see Figure 1 .

[0067] The chemical synthesis route of this example 1 is as follows:

[0068]

[0069] Example 2

[0070] Dissolve 15 g (0.1 mol) of compound 1 in 450 g of chloroform, then add 10.08 g (0.03 mol) of compound 2, and then add 38.34 g (0.2 mol) of EDC and 2.44 g (0.02 mol) of DMAP successively, stir at 45 °C for 12 h, TLC analysis shows that the reaction is complete, wash the reaction liquid with water once, then wash with 2 wt% HCl once, and then wash with 8 wt% sodium bicarbonate once, concentrate the organic phase, and recrystallize the solid with DMF to obtain compound 3, with a yield of 95%. The nuclear magnetic hydrogen spectrum data are the same as those in Example 1.

[0071] Example 3

[0072] Dissolve 15 g (0.1 mol) of compound 1 in 450 g of chloroform, then add 10.08 g (0.03 mol) of compound 2, and then add 38.34 g (0.2 mol) of EDC and 2.44 g (0.02 mol) of DMAP successively, stir at 45 °C for 12 h, TLC analysis shows that the reaction is complete, wash the reaction liquid with water once, then wash with 2 wt% HCl once, and then wash with 8 wt% sodium bicarbonate once, concentrate the organic phase, and recrystallize the solid with DMF to obtain compound 3, with a yield of 95%. The nuclear magnetic hydrogen spectrum data are the same as those in Example 1. 1 H NMR (400 MHz, CDCl3) δ 10.16 (s, 2H), 8.38 (d, 4H, J = 8.0 Hz), 8.05 (d, 4H, J = 8.0 Hz), 7.33 (s, 4H).

[0073]

[0074] Example 4

[0075] Dissolve 15 g (0.1 mol) of compound 1 in 450 g of chloroform, then add 10.08 g (0.03 mol) of compound 2, and then add 38.34 g (0.2 mol) of EDC and 2.44 g (0.02 mol) of DMAP successively, stir at 45 °C for 12 h, TLC analysis shows that the reaction is complete, wash the reaction liquid with water once, then wash with 2 wt% HCl once, and then wash with 8 wt% sodium bicarbonate once, concentrate the organic phase, and recrystallize the solid with DMF to obtain compound 3, with a yield of 95%. The nuclear magnetic hydrogen spectrum data are the same as those in Example 1.

[0076] Example 5

[0077] Compound 6 was obtained by dispersing 6 g (0.01 mol) of compound 3 in a mixed solution of 60 g of acetone and 20 g of water, adding 3.6 g (0.04 mol) of NaClO2, and heating at 15°C for 48 h, then adding 50 mL of 0.1 wt% hydrochloric acid, stirring for 30 min, and then suction-filtering, followed by beating with 24 g of N,N-dimethylformamide at 40°C for 12 h, suction-filtering after cooling, then beating with 48 mL of water at 15°C for 6 h, suction-filtering, and repeating the water-beating process three times, and drying. The yield was 89%. The nuclear magnetic hydrogen spectrum data of compound 6 were as follows: 1 H NMR (400 MHz, DMSO-d6) δ 8.26 (d, 4H, J = 8.4 Hz), 8.15 (d, 4H, J = 8.4 Hz), 7.51 (m, 8H), see Figure 2 .

[0078] The synthetic route of Example 5 was as follows:

[0079]

[0080] Example 6

[0081] Compound 7 was obtained by dispersing 3.74 g (0.01 mol) of compound 5 in a mixed solution of 50 g of t-butyl alcohol and 20 g of water, adding 3.6 g (0.04 mol) of NaClO2, and heating at 45°C for 6 h, then adding 30 mL of 0.1 wt% hydrochloric acid, stirring for 30 min, and then suction-filtering, followed by beating with 22 g of acetic acid at 80°C for 2 h, suction-filtering after cooling, then beating with 15 mL of water at 15°C for 6 h, suction-filtering, and repeating the water-beating process three times, and drying. The yield was 89%. The nuclear magnetic hydrogen spectrum data of compound 7 were as follows: 1 H NMR (400 MHz, DMSO-d6) δ 8.25 (d, 4H, J = 8.0 Hz), 8.14 (d, 4H, J = 8.0 Hz), 7.45 (s, 4H).

[0082] The synthetic route of Example 6 was as follows:

[0083]

[0084] Example 7

[0085] Compound 1 was dissolved in 300 g of dichloromethane (DCM), then 18.6 g (0.1 mol) of compound 8 was added, followed by the addition of 38.34 g (0.2 mol) of EDC and 48.8 g (0.4 mol) of DMAP, 10 °C stirring for 12 h, thin layer chromatography (TLC) analysis showed that the reaction was complete, the reaction liquid was washed with water once, then washed with 0.2 wt% hydrochloric acid once, and then washed with 1 wt% sodium bicarbonate once, the organic phase was concentrated, the solid was recrystallized with acetic acid, and compound 9 was obtained with a yield of 90%. The nuclear magnetic resonance hydrogen spectrum data are as follows: 1 H NMR (400 MHz, CDCl3) δ 10.17 (s, 2H), 8.40 (d, 4H, J = 8.0 Hz), 8.05 (d, 4H, J = 8.0 Hz), 7.67 (d, 4H, J = 8.0 Hz), 7.34 (d, 4H, J = 8.0 Hz), see Figure 3 .

[0086] The chemical synthesis route of this example 7 is as follows:

[0087]

[0088] Example 8

[0089] Compound 9 was dispersed in a mixed solution of 60 g of acetone and 20 g of water, 3.6 g (0.04 mol) of NaClO2 was added, heated at 15 °C for 48 h, then 50 mL of 0.1 wt% hydrochloric acid was added, stirred for 30 min, then filtered, then 14.4 g of N, N-dimethylformamide was beaten at 40 °C for 6 h, cooled and filtered, then 32 g of water was beaten at a temperature of 35 °C for 0.5 h, filtered, and the water beating process was repeated 6 times, and dried to obtain compound 10 with a yield of 89%. The nuclear magnetic resonance hydrogen spectrum data of compound 10 are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 8.28 (d, 4H, J = 8.0 Hz), 8.17 (d, 4H, J = 8.0 Hz), 7.83 (d, 4H, J = 8.0 Hz), 7.45 (d, 4H, J = 8.0 Hz), see Figure 4 .

[0090] The synthesis route of this example 8 is as follows:

[0091]

[0092] Example 9

[0093] In a four-necked flask, 812 mg (2.0 mmol) of compound 7 and 432 mg (1.0 mmol) of compound 11 were mixed well, then 8 g of polyphosphoric acid (containing 85 wt% P2O5) was added, and heated under nitrogen protection at a temperature of 190-200 °C for 6 h. After the reaction was completed, the reaction solution was cooled to room temperature, washed with water for 5 times, and measured to have a pH of 6.0. Then, the solution was dried at 80 °C to obtain a polymer 12 having a number average molecular weight of 49,400 daltons and a dispersity of 2.23.

[0094] The polymer 12 was dissolved in N-methyl pyrrolidone to prepare a 20 wt% solution, filtered with an organic filter membrane, vacuum dried and defoamed, coated on a clean glass plate, and cast into a film by a doctor blade method to have a thickness of about 20 μm. The solvent was removed in a vacuum drying oven at 80 °C, and then heated at 150 °C for 1 h to obtain a thin film 1.

[0095] The synthesis route of the polyarylate of Example 9 is as follows:

[0096]

[0097] Example 10

[0098] In a four-necked flask, 812 mg (2.0 mmol) of compound 7 and 432 mg (1.0 mmol) of compound 11 were mixed well, then 8 g of polyphosphoric acid (containing 85 wt% P2O5) was added, and heated under nitrogen protection at a temperature of 190-200 °C for 6 h. After the reaction was completed, the reaction solution was cooled to room temperature, washed with water for 5 times, and measured to have a pH of 6.0. Then, the solution was dried at 80 °C to obtain a polymer 12 having a number average molecular weight of 49,400 daltons and a dispersity of 2.23.

[0099] The polymer 12 was dissolved in N-methyl pyrrolidone to prepare a 20 wt% solution, filtered with an organic filter membrane, vacuum dried and defoamed, coated on a clean glass plate, and cast into a film by a doctor blade method to have a thickness of about 20 μm. The solvent was removed in a vacuum drying oven at 80 °C, and then heated at 150 °C for 1 h to obtain a thin film 1.

[0100] Example 11

[0101] In a four-necked flask, 812 mg (2.0 mmol) of compound 7 and 432 mg (1.0 mmol) of compound 11 were mixed well, then 8 g of polyphosphoric acid (containing 85 wt% P2O5) was added, and heated under nitrogen protection at a temperature of 190-200 °C for 6 h. After the reaction was completed, the reaction solution was cooled to room temperature, washed with water for 5 times, and measured to have a pH of 6.0. Then, the solution was dried at 80 °C to obtain a polymer 12 having a number average molecular weight of 49,400 daltons and a dispersity of 2.23.

[0102] Polymer 14 was dissolved in N-methylpyrrolidone to form a 20 wt% solution, which was filtered with an organic filter membrane, vacuum dried and degassed, coated on a clean glass plate, and cast into a film with a doctor blade method to form a film with a thickness of about 20 μm. The solvent was removed in a vacuum oven at 80°C, and then the film was heated at 150°C for 1 h to obtain film 3.

[0103] The synthetic route of the polyarylester of this example 12 is as follows:

[0104]

[0105] Example 12

[0106] In a four-necked flask, 1.264 g (2.0 mmol) of compound 6 and 496 mg (2.0 mmol) of compound 15 were mixed well, and then 24 g of polyphosphoric acid (containing 85 wt% P2O5) was added. The mixture was heated at a temperature of 160-170°C for 24 h under nitrogen protection. After cooling to room temperature, the reaction solution was washed with water for 5 times, and the pH was measured to be 6.0. The solution was dried at 80°C to obtain polymer 16, which had a number average molecular weight of 41800 Dalton and a dispersity of 2.45.

[0107] Polymer 16 was dissolved in N-methylpyrrolidone to form a 20 wt% solution, which was filtered with an organic filter membrane, vacuum dried and degassed, coated on a clean glass plate, and cast into a film with a doctor blade method to form a film with a thickness of about 20 μm. The solvent was removed in a vacuum oven at 80°C, and then the film was heated at 150°C for 1 h to obtain film 4.

[0108] The synthetic route of the polyarylester of this example 12 is as follows:

[0109]

[0110] Example 13

[0111] In a four-necked flask, 1.264 g (2.0 mmol) of compound 6 and 432 mg (2.0 mmol) of compound 11 were mixed well, and then 8 g of polyphosphoric acid (containing 85 wt% P2O5) was added. The mixture was heated at a temperature of 190-200°C for 6 h under nitrogen protection. After cooling to room temperature, the reaction solution was washed with water for 5 times, and the pH was measured to be 6.0. The solution was dried at 80°C to obtain polymer 17, which had a number average molecular weight of 38800 Dalton and a dispersity of 2.15.

[0112] Polymer 17 was dissolved in N-methylpyrrolidone to form a 20 wt% solution, which was filtered with an organic filter membrane, vacuum dried and degassed, coated on a clean glass plate, and cast into a film with a thickness of about 20 μm by using a doctor blade method. The solvent was removed in a vacuum oven at 80°C, and then the film was heated at 150°C for 1 h to obtain film 5.

[0113] The synthetic route of the polyarylester of this example 14 is as follows:

[0114]

[0115] Example 14

[0116] In a four-necked flask, 964 mg (2.0 mmol) of compound 10 and 432 mg (2.0 mmol) of compound 11 were mixed well, and then 16 g of polyphosphoric acid (containing 85 wt% P2O5) was added. The reaction was carried out at a temperature of 190-200°C under nitrogen protection for 6 h. After the reaction was completed, the reaction solution was cooled to room temperature, washed with water 5 times, and measured to have a pH of 6.0. Then, the solution was dried at 80°C to obtain polymer 18, which has a number average molecular weight of 32900 Dalton and a dispersity of 2.37.

[0117] Polymer 18 was dissolved in N-methylpyrrolidone to form a 20 wt% solution, which was filtered with an organic filter membrane, vacuum dried and degassed, coated on a clean glass plate, and cast into a film with a thickness of about 20 μm by using a doctor blade method. The solvent was removed in a vacuum oven at 80°C, and then the film was heated at 150°C for 1 h to obtain film 6.

[0118] The synthetic route of the polyarylester of this example 14 is as follows:

[0119]

[0120] Performance test:

[0121] The polyarylester materials prepared in examples 9-14 were tested for glass transition temperature, thermal decomposition temperature and optical performance in sequence.

[0122] Glass transition temperature test method: The glass transition temperature of a polymer sample was measured by using differential scanning calorimetry (DSC). During the measurement, 5-10 mg of the sample was placed in a DSC aluminum crucible, tightly sealed, and the temperature and heat flow signals of the DSC were calibrated by using a standard substance zinc. The temperature was raised from room temperature to 400°C at a rate of 10°C / min, then quickly cooled to the initial temperature to eliminate thermal history, and then raised to the same temperature at the same rate, and the data was recorded.

[0123] Thermal decomposition temperature test method: thermal decomposition temperature of the polymer sample is tested by thermal gravimetric analysis (TGA). 5-20 mg sample is taken, and the temperature curve of thermal weight loss is analyzed by increasing the temperature from 40℃ to 700℃ at a rate of 10℃ / min to obtain the temperature at which 5% weight loss occurs.

[0124] Optical performance test method: the light transmittance of the film is tested by using a UV-visible near infrared spectrometer, and the transmittance values at 450 nm and 500 nm are taken.

[0125] The specific test results are shown in Table 1.

[0126] Table 1:

[0127]

[0128] Embodiments 9-14 of the present application prepared a series of polyarylate based on symmetric ester-containing aromatic dicarboxylic acid and aromatic amine; as can be seen from the test results in Table 1, the glass transition temperature of the polyarylate is 315-356℃, and the thermal decomposition temperature is 427-492℃, proving that the polyarylate has excellent thermal stability and high temperature resistance; in the optical performance test, the transmittance of the polyarylate at 450 nm is 87.6-90.5%, and the transmittance at 500 nm is 88.6-91.7%, proving that the polyarylate has excellent optical transmittance, and can be used as an optical film material after film formation.

[0129] Further acid and alkali resistance test of the polyarylate material prepared in embodiments 9-14. The specific test method is as follows: the film 4 obtained in embodiment 12 is immersed in 1wt% hydrochloric acid and 1wt% sodium hydroxide solution at room temperature for 7 days, and is irradiated under 254 nm ultraviolet lamp for 48 h to obtain film 4-HCl, film 4-NaOH, and film 4-hv, respectively, and the optical transmittance of the three obtained films is tested.

[0130] The specific test results are shown in Table 2.

[0131] Table 2:

[0132] Test Example Film 4 Film 4-HCl Film 4-NaOH Film 4-hv 450 nm light transmittance 90.2％ 88.7％ 87.4％ 88.3％ 500 nm transmittance 90.5％ 89.1％ 88.7％ 88.9％

[0133] As can be seen from the test results in Table 2, the polymer film prepared by the method of the present application has only less than 2% loss of light transmittance after acid, alkali and ultraviolet light irradiation, indicating that the polymer film prepared by the method of the present application has good acid and alkali resistance and anti-aging performance.

[0134] As Comparative Example 1, a polyarylate of a bisphenol A structure (Dingtaoguo. Preparation and performance research of bisphenol type polyarylate [D]. Anhui University of Technology, 2022.) comprising two structures of polyarylate PAR and polyarylate PBR as shown below:

[0135]

[0136] The glass transition temperature T g of the polyarylate PAR is 210℃, and the glass transition temperature T g of the polyarylate PBR is 202℃; both of which are much lower than the polyarylate material synthesized in the present application.

[0137] As Comparative Example 2, a copolymer polyarylate (Ma X C, Niu H J, Cai W A, et al. New high-solubility aromatic polyesters with pendent phenothiazine: synthesis, electrochromic and optoelectronic properties [J]. Reactive and Functional Polymers, 2016, 108: 63-70.) whose chemical structural formula is as shown below:

[0138]

[0139] The glass transition temperature T g of the copolymer polyarylate is 191℃.

[0140] Compared with Comparative Example 1 and Comparative Example 2, in Examples 9 to 14 of the present application, the structural characteristics of the aromatic heterocycle improve the intermolecular π-π strong interaction force and the polar interaction of the polyarylate, and in addition to the rigidity of the structure, it has a higher glass transition temperature.

[0141] Further gas permeability tests were performed on the polyarylate materials prepared in Examples 9 to 14; the specific test method is as follows: the membrane is installed between the upper chamber (which can introduce high pressure gas) and the lower chamber (which is kept vacuum before the experiment begins) of the gas separation device, and the permeation rates of H2, He, O2, N2 and CO2 of the membrane are determined in turn by using the constant volume pressure change method at 35℃, 2bar upstream pressure, and the permeation rate is determined using the following formula. Before testing, the polymer is degassed for at least 24h. After obtaining the permeation rate, the permeation rate of He is divided by the permeation rate of O2, N2 and CO2 respectively to obtain the corresponding ratio, so as to evaluate the permeation selectivity of the membrane to He.

[0142]

[0143] where P is permeance (Barrer), 1 Barrer = 10 -10 · cm 3 · cm·cm -2 s -1 · cmHg -1 , V d is the calibrated permeation volume (cm 3 ), 1 is the membrane thickness (cm), P up is the upstream pressure (cmHg), A is the effective membrane area (cm 2 ), T is the operating temperature (K), R is the gas constant (0.278 cm 3 · cmHg· cm -3 · K -1 ), dp / dt is the downstream pressure increase at steady state (cmHg· s -1 ).

[0144] The specific test results are shown in Table 3.

[0145] Table 3:

[0146]

[0147] From the test results in Table 3, the selectivity values of H2 / CO2, He / N2, He / CO2, He / O2 of the thin film 1 are 2.51, 32.39, 3.64, 19.58 respectively; the selectivity values of H2 / CO2, He / N2, He / CO2, He / O2 of the thin film 2 are 2.16, 27.08, 3.15, 17.26 respectively; the selectivity values of H2 / CO2, He / N2, He / CO2, He / O2 of the thin film 3 are 2.42, 27.23, 3.36, 20.81 respectively; the selectivity values of H2 / CO2, He / N2, He / CO2, He / O2 of the thin film 4 are 3.29, 27.76, 4.28, 21.52 respectively; the selectivity values of H2 / CO2, He / N2, He / CO2, He / O2 of the thin film 5 are 1.63, 18.83, 2.64, 16.48 respectively; the selectivity values of H2 / CO2, He / N2, He / CO2, He / O2 of the thin film 6 are 1.67, 23.92, 2.59, 17.88 respectively. In summary, the obtained thin films all exhibit good separation performance for hydrogen and helium, which proves the use of the thin films in efficient separation and purification of helium from air.

Claims

1. A symmetrical ester-containing aromatic dicarboxylic acid, characterized in that: Its chemical structural formula is: In the formula, the substituent R is selected from Cl, F, Br, CH3O, CH3, H; n is the number of substituents R, which is 1, 2, 3 or 4; Ar is a group with an aromatic ring structure, which is selected from:

2. The symmetrical ester-containing aromatic dicarboxylic acid according to claim 1, characterized in that It is prepared by sequentially subjecting 4-formylbenzoic acid or its derivatives to esterification reaction and aldehyde group oxidation reaction with aromatic ring-containing dihydric phenol; wherein, The chemical structural formula of 4-formylbenzoic acid or its derivatives is: Wherein, X is chlorine or hydroxyl; the substituent R is selected from Cl, F, Br, CH3O, CH3, H; n is the number of substituents R, which is 1, 2, 3 or 4; The aromatic ring-containing diphenol is selected from the following chemical structures:

3. A method for preparing a symmetrical ester-containing aromatic dicarboxylic acid according to claim 1, characterized in that: The steps are: (1) 4-formylbenzoic acid or its derivative, aromatic ring-containing diphenol and an activator are added to a non-protonic polar organic solvent, and reacted at 10°C to 45°C for 12 hours to 72 hours under stirring conditions; the reaction product is sequentially washed with water, washed with dilute hydrochloric acid, washed with alkali and recrystallized to prepare an ester-containing aromatic dialdehyde; wherein the selection of the activating agent is related to the chemical structure of 4-formylbenzoic acid or its derivative; when X is hydroxyl, the activator is a mixture of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4-dimethylaminopyridine, or a mixture of dicyclohexylcarbodiimide and 4-dimethylaminopyridine; when X is chlorine, the activator is an organic base; (2) adding an ester-containing aromatic dialdehyde and an oxidant to a solvent, and reacting at 10°C to 45°C for 6h to 48h under stirring conditions; after the reaction is completed, acidifying, filtering and beating to prepare a symmetrical ester-containing aromatic dicarboxylic acid.

4. The method for preparing a symmetrical ester-containing aromatic dicarboxylic acid according to claim 3, wherein: The molar ratio of 4-formylbenzoic acid or its derivatives to the aromatic ring-containing diphenol is preferably 1:(0.3-0.5); in the chemical structure of 4-formylbenzoic acid or its derivatives, when X is a hydroxyl group, the molar ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride to 4-dimethylaminopyridine, or the molar ratio of dicyclohexylcarbodiimide to 4-dimethylaminopyridine is 1:(0.1-2), and the molar ratio of 4-formylbenzoic acid or its derivatives to 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, or the molar ratio of 4-formylbenzoic acid or its derivatives to dicyclohexylcarbodiimide is 1:(1-2); when X is chlorine, the molar ratio of 4-formylbenzoic acid or its derivatives to the organic base is 1:(1-1.5).

5. The method for preparing a symmetrical ester-containing aromatic dicarboxylic acid according to claim 3, wherein: In step (2), the oxidant is sodium chlorite; the molar ratio of the asymmetric ester-containing aromatic dialdehyde or its derivative to the oxidant is 1:(2-5).

6. The method for preparing a symmetrical ester-containing aromatic dicarboxylic acid according to claim 3, wherein: In step (1), the aprotic polar organic solvent is dichloromethane, chloroform, carbon tetrachloride or 1,2-dichloroethane, and its amount is 10 to 30 times the mass of 4-formylbenzoic acid or its derivative; in step (2), the solvent is one of water, tert-butanol, acetone or a mixture of two of them in any ratio, and its amount is 10 to 20 times the mass of the asymmetric ester-containing aromatic dialdehyde or its derivative.

7. A polyarylate prepared from the asymmetric ester-containing dicarboxylic acid according to claim 1, characterized in that: The chemical structure of polyarylate is: Where, Use one of the following chemical formulas: m is the degree of substitution, m=100 to 10,000.

8. A method for preparing polyarylate according to claim 1, characterized in that: The steps are: Step 1: Mix ester-containing dicarboxylic acid, aromatic amine and polyphosphoric acid, and react at 160° C. to 200° C. under nitrogen protection for 6 to 48 hours; Step 2: Wash the reaction product obtained in step 1 with water at room temperature until the pH value is 6-7, and dry the obtained solid to obtain polyarylate.

9. The method for preparing polyarylate according to claim 8, wherein: In step 1, the molar ratio of the asymmetric ester-containing aromatic dicarboxylic acid to the aromatic amine is 1:(0.97-1.02), and the amount of polyphosphoric acid used is 8 to 20 times the weight of the asymmetric ester-containing aromatic dicarboxylic acid.

10. An application of the polyarylate according to claim 7, characterized in that: The applications after film preparation are: 1) utilizing its heat resistance, acid and alkali resistance to be used as a substrate and battery separator; 2) utilizing its heat resistance and optical properties to be used as an optical film on color filters, printed materials, luminescent materials, electronic devices, flexible displays, liquid crystal display devices, and electronic paper; 2) utilizing its gas separation properties to be used as a gas separation membrane to separate helium from the air.

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