Asymmetric ester group-containing dicarboxylic acid, polyarylester, preparation method and application

Abstract

The invention discloses asymmetric ester group-containing dicarboxylic acid, polyarylester, a preparation method and application. The asymmetric ester group-containing dicarboxylic acid is prepared from 4-formylbenzoic acid or a derivative thereof and p-hydroxybenzaldehyde or a derivative thereof through an esterification reaction and an aldehyde group oxidation reaction in sequence; the polyarylester is obtained by copolymerizing asymmetric ester group-containing dicarboxylic acid and aromatic amine; the main chain structure of the polyarylester contains heteroaromatic rings, so that the interaction force among polyarylester molecules is remarkably enhanced, the glass transition temperature and the thermal decomposition temperature of the polyarylester are greatly improved, and the polyarylester has excellent thermal stability and high-temperature-resistant application prospects, is remarkably higher than those of existing polyarylester materials, and shows certain toughness; meanwhile, the polyarylester has excellent gas separation performance after film formation, particularly has good selectivity to hydrogen, and is obviously superior to that of traditional polyarylester.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, in particular to an asymmetric ester group-containing dicarboxylic acid, 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 chain segments, 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 has a low melting temperature, generally between 200-270℃, which limits its application under high temperature conditions and cannot meet the special requirements of aerospace, military and other fields for the heat resistance and mechanical properties of materials. The existing polyarylate monomers are relatively few, which cannot meet the needs of multifunctional polyarylate design; on the other hand, the traditional polyarylate is polymerized by esterification reaction between monomers, which limits the molecular weight of polyarylate to some extent, and the polymerization process is high in energy consumption, which is not conducive to the polymerization reaction. SUMMARY

[0004] The purpose of the present application is to provide an asymmetric ester group-containing dicarboxylic acid for synthesizing high heat-resistant and high mechanical property polyarylate and a preparation method thereof.

[0005] Another purpose of the present application is to provide a polyarylate prepared from the asymmetric ester group-containing dicarboxylic acid and a preparation method thereof.

[0006] Another purpose of the present application is to provide an application of the polyarylate.

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

[0008] An asymmetric ester group-containing dicarboxylic acid has the following chemical structure:

[0009]

[0010] In the formula, the substituent group R1 and the substituent group R2 are each selected from one of Cl, F, Br, CH3O and CH3, n is 0, 1, 2, 3 or 4; m and n are the number of substituents, and the values of the two are 0, 1, 2, 3 or 4.

[0011] Specifically, the asymmetric ester-containing dicarboxylic acid is prepared by esterification and oxidation of an aldehyde group from 4-aldehydebenzoic acid or its derivative and p-hydroxybenzaldehyde or its derivative; wherein,

[0012] The chemical structural formula of 4-aldehydebenzoic acid or its derivative is:

[0013]

[0014] In the formula, X is chlorine or hydroxyl; R1 is a substituent, preferably R1 is one of Cl, F, Br, CH3O, and CH3; R1 is located at any position on the benzene ring except the aldehyde group and -COX; n is the number of R1 substituents, and n is 0, 1, 2, 3, or 4;

[0015] The chemical structure of p-hydroxybenzaldehyde or its derivative is:

[0016]

[0017] In the formula, R2 is a substituent, preferably R2 is one of Cl, F, Br, CH3O, and CH3; R2 is located at any position on the benzene ring except the aldehyde group and the hydroxyl group; m is the number of R2 substituents, and m is 0, 1, 2, 3, or 4.

[0018] Further, the preparation method of the asymmetric ester-containing dicarboxylic acid comprises the following steps:

[0019] (1) Dissolving 4-aldehydebenzoic acid or its derivative, p-hydroxybenzaldehyde or its derivative, and an activating agent in an aprotic polar organic solvent, and reacting at 10-45°C for 12-72h; after the reaction is completed, performing water washing, dilute hydrochloric acid washing, alkali washing, and recrystallization to obtain an asymmetric ester-containing aromatic dialdehyde;

[0020] (2) Dissolving the asymmetric ester-containing aromatic dialdehyde and an oxidizing agent in a solvent, and reacting at 10-45°C for 6-48h; after the reaction is completed, performing acidification, filtration, and beating to prepare the asymmetric ester-containing dicarboxylic acid.

[0021] The chemical synthesis route of the preparation steps is shown in the following formula:

[0022]

[0023] In the preparation step (1) of the asymmetric ester-containing dicarboxylic acid, the molar ratio of 4-aldehydebenzoic acid or its derivative to p-hydroxybenzaldehyde or its derivative is 1:(0.8-1), and is preferably 1:(0.9-1).

[0024] In the asymmetric preparation step (1) of the ester group-containing dicarboxylic acid, the selection of the activating agent is related to the chemical structure of the 4- aldehydebenzoic acid or its derivative, and specifically,

[0025] The chemical structure of the 4-aldehydebenzoic acid or its derivative is as follows:

[0026]

[0027] Case 1: when X is hydroxyl, the activating agent is a mixture of 1-ethyl-(3- dimethylaminopropyl) carbodiimide hydrochloride (EDC) and 4-dimethylaminopyridine (DMAP), or a mixture of dicyclohexyl carbodiimide (DCC) and 4-dimethylaminopyridine (DMAP);

[0028] Case 2: when X is chlorine, the activating agent is an organic base, preferably the activating agent is triethylamine or pyridine.

[0029] Preferably, in case 1, the amount of the activating agent is that the molar ratio of the 4-aldehydebenzoic acid or its derivative to EDC or DCC is 1:(1-2), and the molar ratio of EDC to DMAP or the molar ratio of DCC to DMAP is 1:(0.1-2).

[0030] Preferably, in case 2, the amount of the activating agent is that the molar ratio of the 4-aldehydebenzoic acid or its derivative to the organic base is 1:(1-1.5).

[0031] In the above step (1), the aprotic polar organic solvent is dichloromethane, chloroform, carbon tetrachloride or 1,2-dichloroethane, and the amount of the aprotic polar organic solvent is 10-30 times the mass of the 4-aldehydebenzoic acid or its derivative.

[0032] In the above step (1), the reaction time is preferably 12-48 hours.

[0033] In the above step (1), in the dilute hydrochloric acid washing step, the dilute hydrochloric acid is a 0.2wt%-2wt% hydrochloric acid solution.

[0034] In the above step (1), in the alkali washing step, the alkali solution is a 1wt%-8wt% sodium bicarbonate solution or a 1wt%-20wt% sodium carbonate solution.

[0035] In the above step (1), the recrystallization solvent is one of N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, acetic acid, or a mixture of two of them in any ratio.

[0036] In the above step (2), the oxidizing agent is sodium chlorite; the molar amount of the asymmetric ester group-containing aromatic dialdehyde or its derivative to the oxidizing agent is 1:(2-5).

[0037] In the step (2), the solvent is one or a mixture of two of water, t-butyl alcohol, and acetone in any ratio, and the amount is 10 to 20 times that of the asymmetric ester group-containing aromatic dialdehyde or its derivative.

[0038] In the step (2), the acid washing step uses dilute hydrochloric acid, which is a 0.1wt% to 1wt% hydrochloric acid solution.

[0039] In the step (2), the solvent used for beating is one or a mixture of two of N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, and acetic acid in any ratio.

[0040] In the step (2), the beating operation is as follows: the solid obtained by suction filtration is dispersed in the beating solvent, and then stirred at 40°C to 80°C for 2h to 12h; after the stirring is completed, the temperature is cooled to room temperature, suction filtration is performed, and then the solid obtained by suction filtration is dispersed in water, and the stirring is continued at 15°C to 35°C for 0.5h to 6h; after the stirring is completed, suction filtration is performed, and the above water beating process is repeated 3 to 6 times; wherein the amount of the beating solvent is 4 to 6 times that of the asymmetric ester group-containing aromatic dialdehyde; and the amount of water used for beating is 4 to 8 times that of the asymmetric ester group-containing aromatic dialdehyde.

[0041] A polyarylate, characterized in that the main chain contains an aromatic heterocycle; the chemical structural formula of the polyarylate is:

[0042]

[0043] In the formula, the substituent group R1 and the substituent group R2 are selected from one of Cl, F, Br, CH3O, and CH3, and m and n are the number of substituents, and the values of m and n are 0, 1, 2, 3, or 4; selected from one of the following chemical structures:

[0044]

[0045] k is the degree of substitution, and the value of k is 100 to 10,000.

[0046] In some embodiments of the present application, the number average molecular weight of the polyarylate is in the range of 33,000 to 37,000 Daltons, and the dispersity is between 2.0 and 2.2.

[0047] A preparation method of the polyarylate with the main chain containing an aromatic heterocycle, the preparation steps are:

[0048] Step 1, mixing and reacting the asymmetric ester group-containing dicarboxylic acid prepared above, an aromatic amine, and polyphosphoric acid under nitrogen protection, and placing in a 160°C to 200°C environment for 6 to 48h;

[0049] Step 2, the reaction product obtained from Step 1 is washed with water until pH = 6-7 at room temperature, and the obtained solid is dried to obtain the polyarylate with the main chain containing aromatic heterocycle.

[0050] In Step 1 above, the aromatic amine is selected from compounds with the following chemical structure:

[0051]

[0052] In Step 1 above, 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 added is 8-20 times the weight of the asymmetric ester-containing aromatic dicarboxylic acid. Preferably, the polyphosphoric acid used is polyphosphoric acid with P2O5≥85wt%.

[0053] A gas separation membrane prepared using the above polyarylate with the main chain containing aromatic heterocycle, in particular, the application of the gas separation membrane, which is specifically used for the separation of H2 / CO2 mixed gas.

[0054] A preparation method of a gas separation membrane, comprising the steps of: dissolving the polymer 24 in N,N-dimethylformamide to prepare 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 doctor blade method; then, placing the glass plate coated with the polymer solution in a vacuum drying oven at 60-90°C to remove the solvent, and then heating at 140-160°C for 1-2h to obtain a polymer thin film.

[0055] In the present application, the asymmetric ester-containing dicarboxylic acid can break the symmetry of the molecular chain by introducing a flexible chain segment ester group into the diacid monomer, increase the degree of freedom of chain segment rotation, thereby enhancing the toughness of its copolymer and improving the melt processability; at the same time, by weakening the intermolecular force and increasing the elongation at break, the polyarylate has high heat resistance and strong mechanical properties; on the other hand, the polyarylate realizes the introduction of heteroatoms (polarity, hydrogen bond sites) in the chemical structure by copolymerization with aromatic amine, which cooperates with the structure regulation of rigid aromatic ring to improve the polarity and free volume of the membrane, realizes the synergistic optimization of selective adsorption-diffusion of gas molecules, and makes the membrane structure prepared based on the polyarylate form high-performance gas separation membrane performance.

[0056] Compared with the prior art, the polyarylate prepared by using the asymmetric ester-containing dicarboxylic acid has an aromatic heterocycle in the main chain structure, the interaction force between the polyarylate molecules is significantly enhanced, the glass transition temperature and thermal decomposition temperature of the polyarylate are greatly improved, the polyarylate has excellent thermal stability and high-temperature resistance, is significantly higher than the existing polyarylate material, and has certain toughness; at the same time, the polyarylate film has excellent gas separation performance, specifically has good selectivity to hydrogen, and is obviously better than the traditional polyarylate. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 The nuclear magnetic test diagram of compound 3 prepared for example 1 of the application;

[0058] Figure 2 The nuclear magnetic test diagram of compound 5 prepared for example 2 of the application. DETAILED DESCRIPTION

[0059] The application will be further described below in combination with the drawings and specific examples, but the following examples are by no means any limitation on the application.

[0060] Example 1

[0061] 150 g (1 mol) of compound 1 was dissolved in 1500 g of dichloromethane (DCM), then 122 g (1 mol) of compound 2 was added, and then 383.4 g (2 mol) of EDC and 488 g (4 mol) of DMAP were added in sequence, stirred at 10℃ for 12 h, thin layer chromatography (TLC) analysis showed that the reaction was completed, the reaction liquid was washed once with water, then washed once with 0.2 wt% HCl, and then washed once with 1 wt% sodium bicarbonate, the organic phase was concentrated, the solid was recrystallized with acetic acid, and compound 3 was obtained, with a yield of 95%. 1H NMR (400 MHz, DMSO-d6) δ 10.2 (s, 1), 10.0 (s, 1), 8.45 (d, 2H, J = 7.9 Hz), 8.10 (d, 2H, J = 7.9), 8.05 (d, 2H, J = 7.9), 7.45 (d, 2H, J = 7.9), see Figure 1 .

[0062] The synthesis route of this example 1 is as follows:

[0063]

[0064] Example 2

[0065] DMSO-d6) δ 10.22 (s, 1), 10.13 (s, 1), 8.15 (d, 2H, J = 7.9 Hz), 8.08 (d, 2H, J = 7.9), 7.65 (s, 2H, J = 7.9), 2.13 (s, 3H), 2.09 (s, 3H), see Figure 2 .

[0066] The synthetic route of this Example 2 is as follows:

[0067]

[0068] Example 3

[0069] Dissolve 168.6 g (1 mol) of compound 1 in 1500 g of dichloromethane (DCM), then add 122 g (1 mol) of compound 4, and then add 151.8 g (1.5 mol) of triethylamine, stir at 10°C for 72 h, thin layer chromatography (TLC) analysis shows that the reaction is complete, the reaction liquid is washed once with water, then washed once with 1.5 wt% HC1, and then washed once with 5 wt% sodium bicarbonate, the organic phase is concentrated, the solid is recrystallized with acetic acid, to obtain compound 3, the yield is 93%. NMR results show that the structure is the same as that of Example 1.

[0070] The synthetic route of this Example 3 is as follows:

[0071]

[0072] Example 4

[0073] Disperse 25.4 g (0.1 mol) of compound 3 in a mixed solution of 300 g of acetone and 100 g of water, add 36 g (0.4 mol) of NaClO2, heat at 15°C for 48 h, then add 500 mL of 0.1 wt% hydrochloric acid, stir for 30 min, then filter, then beat with 120 g of N,N-dimethylformamide at 80°C for 2 h, cool and filter, then beat with 120 mL of water at a temperature of 15°C for 6 h, filter, repeat the water beating process 3 times, and dry to obtain compound 6, the yield is 89%.

[0074] The1H NMR data of the compound 6 is as follows:1H NMR (400 MHz, DMSO-d6) δ 13.26 (b, 2H), 8.27 (d, 2H, J = 8.0 Hz), 8.16 (d, 2H, J = 8.0 Hz), 8.07 (m, 4H); the high performance liquid chromatography purity is 99.21%.

[0075] The synthetic route of the example 4 is as follows:

[0076]

[0077] Example 5

[0078] The 28.2 g (0.1 mol) of compound 6 is dispersed in a mixed solution of 260 g of tert-butyl alcohol and 60 g of water, 18 g (0.2 mol) of NaClO2 is added, and the reaction is carried out at 45 °C for 6 h, then 300 mL of 0.5% hydrochloric acid is added, stirred for 30 min, and then filtered, then 165 g of acetic acid is used for beating at 40 °C for 12 h, cooled and filtered, then 225 mL of water is used for beating at a temperature of 35 °C for 0.5 h, filtered, and the water beating process is repeated 6 times, and dried to obtain compound 7, with a yield of 83%.

[0079] The1H NMR data of the compound 7 is as follows:1H NMR (400 MHz, DMSO-d6) δ 8.32 (d, 2H, J = 8.0 Hz), 8.18 (d, 2H, J = 8.0 Hz), 7.77 (s, 2H), 2.23 (s, 3H), 2.19 (s, 3H); the high performance liquid chromatography purity is 99.46%.

[0080] The synthetic route of the example 5 is as follows:

[0081]

[0082] Example 6

[0083] The 18 g (0.1 mol) of compound 8 is dissolved in 540 g of dichloromethane, then 13.52 g (0.09 mol) of compound 9 is added, and then 20.6 g (0.1 mol) of DCC and 24.4 g (0.2 mol) of DMAP are added in sequence, stirred at 25 °C for 72 h, and thin layer chromatography (TLC) analysis shows that the reaction is complete, the reaction liquid is washed once with water, then once with 1 wt% hydrochloric acid, and once with 1 wt% sodium carbonate, the organic phase is concentrated, and the solid is recrystallized with acetic acid to obtain compound 10, with a yield of 90%.

[0084] The synthetic route of the example 6 is as follows:

[0085]

[0086] Example 7

[0087] Dissolve 22.9 g (0.1 mol) of compound 11 in 350 g of chloroform, then add 12.52 g (0.08 mol) of compound 12, and then add 38.34 g (0.2 mol) of EDC and 2.44 g (0.02 mol) of DMAP, stir at 45 °C for 12 h, TLC analysis shows that the reaction is complete, wash the reaction liquid with water once, then with 2 wt% HCl once, and then with 8 wt% sodium bicarbonate once, concentrate the organic phase, and recrystallize the solid with DMF to obtain compound 13, with a yield of 87%.

[0088] The synthetic route of this Example 7 is as follows:

[0089]

[0090] Example 8

[0091] Dissolve 20.46 g (0.1 mol) of compound 14 in 500 g of carbon tetrachloride, then add 15.22 g (0.1 mol) of compound 15, and then add 8.52 g (0.1 mol) of piperidine, stir at 35 °C for 48 h, TLC analysis shows that the reaction is complete, wash the reaction liquid with water once, then with 1.5 wt% HCl once, and then with 20 wt% sodium carbonate once, concentrate the organic phase, and recrystallize the solid with DMF to obtain compound 16, with a yield of 89%.

[0092] The synthetic route of this Example 8 is as follows:

[0093]

[0094] Example 9

[0095] Dissolve 3.18 g (0.01 mol) of compound 10 in a mixture of 26 g of tert-butyl alcohol and 6 g of water, add 1.8 g (0.02 mol) of NaClO2, heat to 45 °C and react for 6 h, then add 30 mL of 0.5% hydrochloric acid, stir for 30 min, then filter, then beat with 15 mL of acetic acid at 50 °C for 6 h, cool and filter, then beat with 15 mL of water at a temperature of 25 °C for 3 h, filter, and repeat the water beating process 6 times, and dry to obtain compound 17, with a yield of 83%.

[0096] The synthetic route of this Example 9 is as follows:

[0097]

[0098] Example 10

[0099] Compound 18 was obtained by dispersing 3.68 g (0.01 mol) of compound 13 in a mixed solution of 50 g of t-butyl alcohol and 23.6 g of water, adding 3.6 g (0.04 mol) of NaClO2, heating at 25°C for 12 h, then adding 20 mL of 1 wt% hydrochloric acid, stirring for 30 min, then suction filtering, then beating with 16 mL of acetic acid at 50°C for 6 h, cooling, suction filtering, then beating with 16 mL of water at 25°C for 2 h, suction filtering, and repeating the water beating process 4 times, and drying to obtain compound 18 at a yield of 90%.

[0100] The synthetic route of this example 10 is as follows:

[0101]

[0102] Example 11

[0103] In a four-necked flask, 2.86 g (10 mmol) of compound 6 and 2.16 g (10 mmol) of compound 19 were mixed uniformly, then 40 g of polyphosphoric acid (containing 85% P2O5) was added, heated under nitrogen protection, and reacted at 190-200°C for 6 h. After cooling to room temperature, the reaction solution was washed with water 5 times, and the pH was measured to be 6.0. The polymer 20 was obtained by drying at 80°C. The number average molecular weight of the polymer 20 was measured to be 36.2 kDa, and the dispersity was 2.1.

[0104] The polymer 20 was dissolved in N-methylpyrrolidone to form a 20 wt% solution, filtered using an organic filter membrane, vacuum dried and defoamed, and then coated on a clean glass plate to form a film by the doctor blade method, with a film thickness of about 20 μm. Then the film was placed in a vacuum drying oven at 80°C to remove the solvent, and then heated at 150°C for 1 h to obtain a polymer film.

[0105] The synthetic route of this example 11 is as follows:

[0106]

[0107] Example 12

[0108] In a four-necked flask, 3.14 g (10 mmol) of compound 7 and 3.72 g (10.2 mmol) of compound 21 were mixed uniformly, then 80 g of polyphosphoric acid (containing 85% P2O5) was added, heated under nitrogen protection, and reacted at 160-170°C for 48 h. After cooling to room temperature, the reaction solution was washed with water 5 times, and the pH was measured to be 6.0. The polymer 22 was obtained by drying at 80°C. The number average molecular weight of the polymer 22 was measured to be 35.5 kDa, and the dispersity was 2.1.

[0109] The polymer 22 was dissolved in N-methylpyrrolidone to form a 20 wt% solution, and filtered with an organic filter membrane. After vacuum drying and degassing, the solution was coated on a clean glass plate, and cast into a film with a doctor blade method, with a film thickness of about 20 μm. The film was then placed in a vacuum drying oven at 80°C to remove the solvent, and heated at 150°C for 1 h to obtain a polymer film.

[0110] The synthetic route of this Example 13 is as follows:

[0111]

[0112] Example 13

[0113] In a four-necked flask, 2.86 g (10 mmol) of compound 6 and 2.68 g (10.2 mmol) of compound 23 were mixed well, and then 40 g of polyphosphoric acid (containing 85% P2O5) was added. The mixture was heated under nitrogen protection, with the temperature controlled at 190-200°C for 6 h. 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 product was dried at 80°C to obtain polymer 24. The number average molecular weight of the polymer 24 was measured to be 33200 Dalton, and the dispersity was 2.2.

[0114] The polymer 24 was dissolved in N,N-dimethylformamide to form a 20 wt% solution, and filtered with an organic filter membrane. After vacuum drying and degassing, the solution was coated on a clean glass plate, and cast into a film with a doctor blade method, with a film thickness of about 20 μm. The film was then placed in a vacuum drying oven at 80°C to remove the solvent, and heated at 150°C for 1 h to obtain a polymer film.

[0115] The synthetic route of this Example 13 is as follows:

[0116]

[0117] Example 14

[0118] In a four-necked flask, 350 mg (1.0 mmol) of compound 17 and 372 mg (1.02 mmol) of compound 21 were mixed well, and then 8 g of polyphosphoric acid (containing 85% P2O5) was added. The mixture was heated under nitrogen protection, with the temperature controlled at 160-170°C for 48 h. 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 product was dried at 80°C to obtain polymer 25. The number average molecular weight of the polymer 25 was measured to be 36500 Dalton, and the dispersity was 2.0.

[0119] The polymer 25 was dissolved in N,N-dimethylformamide to form a 20 wt% solution, and filtered with an organic filter membrane. After vacuum drying and degassing, the solution was 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 film was then placed in a vacuum drying oven at 80°C to remove the solvent, and heated at 150°C for 1 h to obtain a polymer film.

[0120] The polymerization reaction route of this Example 15 is as follows:

[0121]

[0122] Example 15

[0123] In a four-necked flask, 399 mg (1.0 mmol) of compound 18 and 268 mg (1.02 mmol) of compound 23 were mixed well, and then 4 g of polyphosphoric acid (containing 85% P2O5) was added. The mixture was heated under nitrogen protection at a temperature of 190-200°C for 6 h. After cooling to room temperature, the reaction solution was washed with water 5 times, and the pH was measured to be 6.0. The polymer 26 was obtained by drying at 80°C. The number average molecular weight of the polymer 26 was measured to be 34.5 kD, and the dispersity was 2.1.

[0124] The polymer 26 was dissolved in N-methylpyrrolidone to form a 20 wt% solution, and filtered with an organic filter membrane. After vacuum drying and degassing, the solution was 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 film was then placed in a vacuum drying oven at 80°C to remove the solvent, and heated at 150°C for 1 h to obtain a polymer film.

[0125] The polymerization reaction route of this Example 15 is as follows:

[0126]

[0127] Comparative Example 1

[0128] With reference to the preparation method recorded in the published patent CN119410003A, a high-temperature-resistant polyarylate fluorescent film and a preparation method thereof are provided, which comprises the following components by weight: bisphenol A (BPA) 60 parts; bisphenol fluorene (BPF) 30 parts; terephthaloyl chloride (TPC) 55 parts; 18-crown-6 0.5 parts. The preparation method comprises the following steps: S1, adding a mixture containing BPF and 18-crown-6 to a mixed solution of deionized water, stirring at a speed of 120 rpm for 1 h under alkaline conditions to prepare a precursor solution, and controlling the reaction temperature to be 20℃; continuously introducing nitrogen as a protective gas during the reaction process; S2, adding part of the dichloromethane solution containing TPC to the precursor solution, and continuously reacting for 3 h; S3, adding an aqueous solution containing BPA to the above solution, continuously adding the remaining TPC solution, and reacting for 5 h; S4, adding HCl solution drop by drop to the mixed solution until the pH value is 3, then precipitating in an acetone solution, repeatedly washing with deionized water for 5 times, crushing with a broken wall machine at a speed of 25000 rpm, and drying in an oven for 12 h to prepare a dried polyarylate fluorescent material; S5, dissolving the polyarylate fluorescent material in an NMP solution, controlling the solid content to be 20%, coating the solution on a clean glass plate, and drying in a vacuum oven with a vacuum degree of-0.1 MPa and a temperature of 120℃ for 9 h to obtain a high-temperature-resistant polyarylate fluorescent film.

[0129] Comparative Example 2

[0130] With reference to the preparation method recorded in the published patent CN116585910A, a preparation method of an intrinsic microporous polyarylate hollow fiber composite membrane is provided. 1) At 63℃, a mixture of 19 parts of polyether sulfone resin, 1.8 parts of silicone oil and 4.2 parts of polyvinylpyrrolidone K15 is uniformly dissolved in 71 parts of N,N-dimethylacetamide to obtain a casting solution, and further prepared into a hollow fiber membrane; 2) At 190℃, 9 parts of intrinsic microporous polyarylate with a molecular weight of 180,000 and hydroxy porphyrin as a microporous structure unit is uniformly dissolved in 91 parts of diethylene glycol dimyric acid ester to prepare a homogeneous intrinsic microporous polyarylate solution; 3) The prepared polyether sulfone hollow fiber membrane is used as a support, and the intrinsic microporous polyarylate solution is extruded and coated on the surface of the polyether sulfone hollow fiber membrane by using an inner hole diameter of 0.4 mm, an extrusion diameter of the intrinsic microporous polyarylate solution of 0.6 mm and a size of the slit of 0.2 mm, at the same time, the prepared intrinsic microporous polyarylate solution is extruded and coated on the surface of the polyether sulfone hollow fiber membrane to form a composite, and the thickness of the polyarylate surface coating solution is 0.01 mm; 4) Finally, the intrinsic microporous polyarylate hollow fiber blank prepared in step 3) is subjected to a 30 cm 90℃ air bath section, and then enters a 10% polyethylene glycol and 90% glycerol mixed coagulation bath tank with a temperature of 5℃ to undergo phase inversion, and finally the intrinsic microporous polyarylate hollow fiber composite membrane is prepared.

[0131] Comparative Example 3

[0132] Referring to the preparation method described in the published patent CN117264393A, a preparation method of polyarylate fiber reinforced thermoplastic composite for 3D printing is provided. The polyarylate fiber is soaked in an acetone / ethanol solution (ethanol:acetone volume ratio is 1:1) for 60 min, washed with deionized water until neutral, and then vacuum dried at 60°C for 6h. Then the mixture is placed in a vacuum drying oven and dried at 150°C for 1h. The silane coupling agent mixed solution is a mixed solution of silane coupling agent and acetone / water solution, the amount of silane coupling agent is 2% of the mass of polyarylate fiber, and the ratio of acetone / water solution is 0.5wt%. The components are weighed and added to the mixing blender, the mixing blender speed is 1000 rad / min, the mixing time is 5 min, and the mixture is obtained. The mixture is added to a twin-screw extruder for mixing, the extruder temperature is controlled at 140°C, 160°C, 180°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C, 190°C, the main shaft speed is 150 rpm, and the cooling water temperature is 30°C. The cooled filament is cut into granules by a pelletizer. The obtained granules are placed in a vacuum drying oven at 50°C for 6h. The dried granules are added to a single-screw extruder to extrude into a wire, the extruder temperature is controlled at 140°C, 190°C, 200°C, 200°C, 190°C, the main shaft speed is 20 rad / min, the cooling water temperature is 60°C, the traction speed is 25 rad / min, and the extruded wire diameter is controlled at about 1.75mm. The prepared 1.75mm wire is used for printing, and the printed sample is tested for mechanical properties according to standard ASTM D638.

[0133] Performance test:

[0134] The film materials prepared in Examples 9-11 and Comparative Examples 1-3 were tested for glass transition temperature, thermal decomposition temperature, strain, and H2 / CO2 permeation selectivity, respectively.

[0135] Glass transition temperature test method: The glass transition temperature of the polymer sample is measured by differential scanning calorimetry (DSC). During the measurement, 5-10mg of sample is taken and uniformly placed in a DSC aluminum crucible, tightly sealed, and the temperature and heat flow signals of the DSC are calibrated using standard zinc. The temperature is raised from room temperature to 400°C at a rate of 10°C / min, then quickly cooled to the starting temperature to eliminate thermal history, and then raised to the same rate, and the data is recorded.

[0136] Thermal decomposition temperature test method: Thermal decomposition temperature of the polymerized sample was tested by thermogravimetric analysis (TGA). 5-20 mg sample was taken and analyzed for thermal gravimetric temperature curve by increasing the temperature from 40 °C to 700 °C at a rate of 10 °C / min to obtain the temperature at which 5% weight loss occurred.

[0137] Tensile strength and strain performance test method: According to the standard GB / T 1040.3-2006.

[0138] Gas permeability test method: The membrane was installed between the upper chamber (capable of introducing high pressure gas) and the lower chamber (maintained vacuum before the experiment began) of a gas separation device, and the permeation rates of H2, O2, N2 and CO2 of the membrane were determined in turn by constant volume pressure change method at 35 °C, 2 bar upstream pressure. The permeation rate was determined using the following formula. Before testing, the polymer was degassed for at least 24 h. After obtaining the permeation rate, the permeation rate of He was divided by the permeation rates of O2, N2 and CO2 respectively to obtain the corresponding ratio, which was used to evaluate the permeation selectivity of the membrane to He.

[0139]

[0140] In the formula, P is the permeation rate (Barrer), 1 Barrer = 10 -10 cm 3 cm cm -2 s -1 cmHg -1 , V d is the calibrated permeation volume (cm 3 ), l is the membrane thickness (cm), P up is the upstream pressure (cmHg), A is the effective membrane area (cm 2 ), T is the working temperature (K), R is the gas constant (0.278 cm 3 cmHg cm -3 K -1 ), dp / dt is the steady-state downstream pressure increment (cmHg s -1 ).

[0141] The specific performance test results are shown in Table 1 below.

[0142] Table 1:

[0143]

[0144] The polyarylate prepared in Embodiment 11 to Embodiment 15 based on the symmetric aromatic dicarboxylic acid containing ester group and aromatic amine has a glass transition temperature of 331.7-353.4°C, which is all higher than 320°C, especially the glass transition temperature of Embodiment 15 is as high as 353°C. Meanwhile, the thermal decomposition temperature of the polyarylate is 489.3-498.9°C, which proves that the polyarylate has excellent thermal stability and high temperature resistance. The strain of the polyarylate is 4.46-9.37%, which proves that the polyarylate has certain toughness. Meanwhile, the polyarylate can also be used as a gas separation membrane. Specifically, the test results show that the permeation rate ratio of H2 to O2 is 21-32, the permeation rate ratio of H2 to N2 is 68-87, and the permeation rate ratio of H2 to CO is 21-26, which proves that the polyarylate has good selectivity for hydrogen after being formed into a film. 2 and CO 2

[0145] In the above performance test, three comparative examples and the performance difference caused by the chemical structure difference of the present application are also used for comparison. Comparative Example 1 lacks the heterocyclic structure of benzoxazole, benzimidazole, benzothiazole, etc. in the main chain structure, which leads to relatively low glass transition temperature and thermal decomposition temperature. The polyarylate in Comparative Example 2 is a hydroquinone structure unit, which is a traditional polyarylate structure. Due to the significant difference in structure, the polyarylate in the embodiment has good toughness in the strain performance test, but the gas permeability is slightly poor, and it does not have excellent thermal stability and high temperature resistance. Comparative Example 3 is a composite resin containing 1-30% polyarylate component, which also belongs to a traditional polyarylate material. The structural difference leads to low strain performance and tensile strength of the material.​

Claims

1. An asymmetric ester-containing dicarboxylic acid, characterized in that: Its chemical structural formula is: In the formula, the substituent R1 and the substituent R2 are each selected from one of Cl, F, Br, CH3O, and CH3; m and n are the number of substituents, and the values ​​of the two are 0, 1, 2, 3, or 4.

2. The asymmetric ester-containing dicarboxylic acid according to claim 1, characterized in that It is prepared by sequentially subjecting 4-formylbenzoic acid or its derivatives and p-hydroxybenzaldehyde or its derivatives to esterification reaction and oxidation reaction of the aldehyde group; wherein, The chemical structural formula of 4-formylbenzoic acid or its derivatives is: In the formula, X is chlorine or hydroxyl; the substituent R1 is selected from one of Cl, F, Br, CH3O, and CH3; n is the number of R1 substituents, which is 0, 1, 2, 3, or 4; The chemical structure of p-hydroxybenzaldehyde or its derivatives is: In the formula, the substituent R2 is selected from one of Cl, F, Br, CH3O, and CH3; m is the number of R2 substituents, which is 0, 1, 2, 3 or 4.

3. A method for preparing an asymmetric ester-containing dicarboxylic acid as claimed in claim 2, characterized in that the steps include: (1) dissolving 4-formylbenzoic acid or its derivatives, p-hydroxybenzaldehyde or its derivatives and an activator in a non-protonic polar organic solvent and reacting at 10°C to 45°C for 12 hours to 72 hours; after the reaction, washing with water, washing with dilute hydrochloric acid, washing with alkali and recrystallizing to obtain an asymmetric ester-containing aromatic dialdehyde; wherein the selection of the activating agent is related to the chemical structure of 4-formylbenzoic acid or its derivatives; when X is hydroxyl, the activating agent 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 activating agent is an organic base; (2) dissolving an asymmetric ester-containing aromatic dialdehyde and an oxidant in a solvent and reacting them at 10° C. to 45° C. for 6 h to 48 h; after the reaction, acidifying, filtering, and beating to prepare an asymmetric ester-containing dicarboxylic acid.

4. The asymmetric ester-containing dicarboxylic acid according to claim 3, characterized in that In step (1), the molar ratio of 4-formylbenzoic acid or its derivatives to p-hydroxybenzaldehyde or its derivatives is 1:(0.8-1); the amount of the activator is as follows: when X is hydroxyl, the molar ratio of 4-formylbenzoic acid or its derivatives to 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride or dicyclohexylcarbodiimide is 1:(1-2), the molar ratio of EDC to DMAP, or the molar ratio of DCC to DMAP is 1:(0.1-2); 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 asymmetric ester-containing dicarboxylic acid according to claim 3, characterized in that 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 asymmetric ester-containing dicarboxylic acid according to claim 3, characterized in that 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: in, Selected from one of the following chemical structures: k is the degree of substitution, and the value of k ranges from 100 to 10,000.

8. A method for preparing polyarylate according to claim 1, characterized in that: The steps are: Step 1: Mix an asymmetric ester-containing dicarboxylic acid, an 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 prepare 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: Polyarylate is made into a gas separation membrane to effectively separate hydrogen and carbon dioxide gases.

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