Catalyst for polyimide synthesis, its preparation method and use

Abstract

Catalyst for polyimide synthesis. The structural formula of the catalyst is formula (I): [Formula 1] As shown in JPEG2025541993000020.jpg58168, In the formula, Ar 1 and Ar 2 are independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, alkylene, alkenylene, alkynylene, alicyclylene group, heteroarylene group, fused polycyclic arylene group, or a single bond.

Description

[Technical Field]

[0001] This application claims priority to a Chinese patent application filed with the China Patent Office on December 30, 2022, bearing application number 202211726304.7 and titled "Catalyst for polyimide synthesis and its preparation method and use," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of polyimides, and to catalysts for polyimide synthesis and their preparation methods and applications. [Background technology]

[0003] Polyimides have excellent properties, such as high mechanical properties, high and low temperature resistance, flame retardancy, and radiation resistance. They are widely used in national defense, the military industry, microelectronics, vehicles, the chemical industry, and other fields. Currently, polyimide synthesis is mostly performed using nitrogen-containing compounds, such as amines, quinolines, or pyridines, as catalysts. However, nitrogen-containing compounds easily react with non-cyclized precursors to form salts, making catalyst removal difficult. Residual catalysts can affect the film-forming properties of polyimides and reduce product quality. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of this, the present application provides a catalyst for polyimide synthesis, a preparation method thereof and use thereof, such that the catalyst has high catalytic activity and can be used in a small amount in polyimide synthesis, thereby not affecting the film-forming properties of polyimide. [Means for solving the problem]

[0005] In a first aspect, the present application provides a catalyst for polyimide synthesis, the catalyst having a structural formula of Formula (I): [ka] As shown in.

[0006] In the formula, Ar 1 and Ar 2 are independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, alkylene, alkenylene, alkynylene, alicyclylene group, heteroarylene group, fused polycyclic arylene group, or a single bond.

[0007] In one embodiment, the substituted or unsubstituted aryl group is a substituted or unsubstituted C-C 30 It is an aryl group.

[0008] In one embodiment, the substituted or unsubstituted heteroaryl group is a substituted or unsubstituted C-C 30 It is a heteroaryl group.

[0009] In one embodiment, the substituted or unsubstituted alkylene is a substituted or unsubstituted C1-C8 alkylene.

[0010] In one embodiment, the substituted or unsubstituted alkenylene is a substituted or unsubstituted C2-C8 alkenylene.

[0011] In one embodiment, the substituted or unsubstituted alkynylene is a substituted or unsubstituted C2-C8 alkynylene.

[0012] In one embodiment, the substituted or unsubstituted alicyclylene group is a substituted or unsubstituted C-C 30 It is an alicyclylene group.

[0013] In one embodiment, the substituted or unsubstituted heteroarylene group is a substituted or unsubstituted C-C 30 It is a heteroarylene group.

[0014] In one embodiment, the substituted or unsubstituted fused polycyclic arylene group is a substituted or unsubstituted C 10 ~C30 It is a fused polycyclic arylene group.

[0015] In one embodiment, Ar 1 and Ar 2 are independently selected from substituted or unsubstituted aryl groups, and R1 is oxygen, sulfur, sulfone, sulfoxide, carbonyl, or secondary amine.

[0016] In one embodiment, the catalyst is a compound of formula (I-1) to formula (I-5): [ka] The compound includes one of the compounds represented by:

[0017] The catalysts for polyimide synthesis provided in the present application contain phosphorus atoms which make the catalysts more active and can be used in smaller amounts in the synthesis of polyimides, thereby not affecting the film-forming properties of the polyimides.

[0018] In a second aspect, the present application provides a method for preparing a catalyst for polyimide synthesis, the method comprising:

[0019] A first reactant is provided, the structural formula of the first reactant is shown in formula (II), wherein: 2 is selected from a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; [ka]

[0020] A second reactant is provided, the structural formula of the second reactant being shown in formula (III), wherein: 1is selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, alkylene, alkenylene, alkynylene, alicyclylene group, heteroarylene group, fused polycyclic arylene group, or a single bond; H2N-Ar 1 -R1-Ar 1 -NH2(III);

[0021] The first reactant and the second reactant are mixed, and a catalyst for polyimide synthesis is obtained after the first reaction. The structural formula of the catalyst for polyimide synthesis is Formula (I): [ka] As shown in.

[0022] In one embodiment, the molar ratio of the first reactant to the second reactant is 2-3.

[0023] In one embodiment, the first reaction comprises reacting at 25° C. to 150° C. for 2 hours to 48 hours.

[0024] In one embodiment, the method for preparing the first reactant comprises adding magnesium and Ar 2 -X to undergo a second reaction to form Ar 2 -MgX, where X is a halogen; 2 The third reaction was carried out with -MgX and diethylamine dichlorophosphorus to give Ar 2 2P(NEt2) and Ar 2 and subjecting 2P(NEt2) and phosphorus trichloride to a fourth reaction to obtain the first reactant.

[0025] Furthermore, the second reaction involves reacting at 0°C to 80°C for 2 hours to 48 hours.

[0026] Furthermore, the third reaction involves reacting at 0°C to 30°C for 2 to 18 hours.

[0027] Furthermore, the fourth reaction involves reacting at 60°C to 80°C for 1 hour to 10 hours.

[0028] Furthermore, magnesium Ar 2 The molar ratio of - to X is 1: (1 to 1.5).

[0029] Furthermore, Ar in phosphorus trichloride 2 The molar ratio to 2P(NEt2) is greater than 5.

[0030] The method for preparing a catalyst for polyimide synthesis provided in the present application is simple and easy to operate, and can prepare a catalyst with excellent activity, which is beneficial for polyimide synthesis.

[0031] In a third aspect, the present application provides a method for preparing a polyimide, the method comprising mixing the polyimide synthesis catalyst described in the first aspect or the polyimide synthesis catalyst obtained by the preparation method described in the second aspect with a diamine and a dianhydride, and a polyimide is obtained after a fifth reaction.

[0032] The method for preparing polyimides provided in this application is simple, and polyimides can be prepared by a one-step reaction. The operation is simple, the conditions are relatively mild, and no impurity removal is required after the reaction. The products have good performance and good application prospects.

[0033] In a fourth aspect, the present application provides a polyimide prepared by the preparation method described in the third aspect.

[0034] The polyimides provided in this application have excellent performance and good mechanical properties after film formation, which facilitates the use of polyimides. DETAILED DESCRIPTION OF THE INVENTION

[0035] The technical solutions in the embodiments of the present application are clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the present application, any other embodiments obtained by those skilled in the art without creative research shall fall within the scope of protection of the present application.

[0036] The present application provides a catalyst for synthesizing polyimides, the structural formula of the catalyst being Formula (I): [ka] As shown in.

[0037] In the formula, Ar 1 and Ar 2 are independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, alkylene, alkenylene, alkynylene, alicyclylene group, heteroarylene group, fused polycyclic arylene group, or a single bond.

[0038] Current catalysts used to synthesize polyimides, such as pyridine or quinoline catalysts, primarily react via the lone electron pair of the nitrogen atom. Because nitrogen belongs to the second period, its orbital is relatively restricted compared to the same main group elements, and therefore the relative activity of its lone electron pair in catalytic reactions is relatively weak. The catalyst provided by the present application contains a phosphorus atom, which has a more extended orbital compared to the nitrogen atom, which is beneficial for improving reaction activity, lowering the temperature required for the reaction, and promoting the reaction to proceed under milder conditions, thereby reducing production costs and improving production efficiency. In addition, the catalyst provided by the present application has high catalytic activity, is used in small amounts in the process of synthesizing polyimides, and does not affect the film-forming properties of the polyimide if not removed, thereby facilitating the production of polyimides with excellent performance.

[0039] In this application, Ar 1 and Ar2 are independently selected from a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, which means that Ar 1 is selected from a substituted aryl group, an unsubstituted aryl group, a substituted heteroaryl group, or an unsubstituted heteroaryl group; Ar 2 is selected from a substituted aryl group, an unsubstituted aryl group, a substituted heteroaryl group, or an unsubstituted heteroaryl group. In this application, R1 is oxygen, sulfur, sulfone, sulfoxide, carbonyl, a secondary amine, alkylene, alkenylene, alkynylene, an alicyclylene group, a heteroarylene group, a fused polycyclic arylene group, or a single bond.

[0040] In the present application, an aryl group is an aromatic group, which may be a monocyclic aromatic group, a polycyclic aromatic group, or a fused polycyclic aromatic group; a monocyclic aromatic group refers to an aromatic group having only one aromatic ring in the molecule, a polycyclic aromatic group refers to an aromatic group having two or more independent aromatic rings in the molecule, and a fused polycyclic aromatic group refers to an aromatic group having two or more aromatic rings in the molecule that are fused to each other by sharing two adjacent carbon atoms. Specifically, the aryl group may include, but is not limited to, at least one of phenyl, naphthyl, anthracenyl, naphthacene, pentacene, and tetrahydronaphthyl. In an embodiment of the present application, a substituted or unsubstituted aryl group is a substituted or unsubstituted C6-C6 30 It is an aryl group; that is, the number of carbon atoms in the aryl group is 6 to 30. Specifically, the number of carbon atoms in the aryl group is not limited, but may be 6, 10, 13, 15, 18, 20, 23, 25, 29, or 30, etc.

[0041] In the present application, a heteroaryl group refers to an aryl group containing at least one heteroatom, including a monocyclic heteroaryl group or a fused heteroaryl group, where the heteroatom is selected from oxygen, sulfur, nitrogen, or the like. Specifically, the heteroaryl group may include, but is not limited to, at least one of pyridyl, furyl, thienyl, indolyl, quinolyl, imidazolinyl, and thiazolyl. In an embodiment of the present application, a substituted or unsubstituted heteroaryl group is a substituted or unsubstituted C2-C 30 that is, the number of carbon atoms in the heteroaryl group is 2 to 30. Specifically, the number of carbon atoms in the heteroaryl group is not limited, but may be 3, 5, 8, 10, 12, 15, 18, 20, 25, 27, or 30.

[0042] In the present application, alkylene is a divalent saturated group obtained by removing one hydrogen atom from an alkyl group. Specifically, alkylene may include, but is not limited to, at least one of -CH-, -CHCH-, -CHCHCHCHCH-, -CHCHCHCHCHCH-, -CHCHCHCHCHCHCH-, and -CHCHCHCHCHCHCHCHCHCHCH-. In an embodiment of the present application, substituted or unsubstituted alkylene is substituted or unsubstituted C1-C8 alkylene; that is, the number of carbon atoms in the alkylene is 1 to 8. Specifically, the number of carbon atoms in the alkylene may be, but is not limited to, 1, 2, 3, 4, 5, 6, 7, or 8.

[0043] In the present application, alkenylene is a divalent unsaturated group formed by removing one hydrogen atom from an alkenyl group. Specifically, alkenylene may include, but is not limited to, at least one of -CH=CH-, -CH=CHCH2-, -CH2CH=CH-, -CH=CHCH2CH2-, -CH2CH2CH=CH-, -CH2CH=CHCH2-, -CH=CH-CH=CH-, -CH=CHCH2CH2-, -CH=CH-CH=CH-, -CH=CHCH2CH2-, -CH=CH-CH=CH-, -CH=CHCH2CH2-, -CH=CH-CH=CH2CH2-, and -CH=CH2CH2CH=CH-. In an embodiment of the present application, the substituted or unsubstituted alkenylene is a substituted or unsubstituted C2-C8 alkenylene; that is, the number of carbon atoms in the alkenylene is 2 to 8. Specifically, the number of carbon atoms in the alkenylene may be, but is not limited to, 2, 3, 4, 5, 6, 7, or 8.

[0044] In this application, alkynylene is a divalent unsaturated group obtained by removing one hydrogen atom from an alkynyl group. Specifically, alkynylene includes, but is not limited to, -C≡C-, -C≡CCH2-, -CH2C≡C-, -C≡CCH2CH2-, -CH2C≡CCH2-, -CH2CH2C≡C-, -C≡CC≡C-, -C≡CCH2CH2CH2-, -CH2C≡CCH2CH2-, -CH2CH2C≡CCH2-, -CH2C≡CC≡ The alkynylene may include C-CH2-, -C≡CCH2CH2CH2-, -CH2CH2C≡CCH2-, -CH2C≡CC≡C-CH2-, -C≡CCH2CH2CH2-, -CH2C≡CCH2CH2-, -CH2CH2C≡CCH2CH2-, -CH2CH2C≡CCH2-, and -CH2CH2CH2CH2C≡C-. In an embodiment of the present application, the substituted or unsubstituted alkynylene is a substituted or unsubstituted C2-C8 alkynylene; that is, the number of carbon atoms in the alkynylene is 2 to 8. Specifically, the number of carbon atoms in the alkynylene may be, but is not limited to, 2, 3, 4, 5, 6, 7, or 8.

[0045] In the present application, an alicyclylene group is a divalent alicyclic group. Specifically, the alicyclylene group may include, but is not limited to, at least one of a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, and a cyclopentenylene group. In an embodiment of the present application, the substituted or unsubstituted alicyclylene group is a substituted or unsubstituted C3-C 30 that is, the number of carbon atoms in the alicyclylene group is 3 to 30. Specifically, the number of carbon atoms in the alicyclylene group is not limited, but may be 3, 5, 9, 10, 13, 15, 18, 23, 26, or 30.

[0046] In the present application, a heteroarylene group is a divalent heteroaryl group. Specifically, the heteroarylene group may include, but is not limited to, at least one of a pyridylene group, a furylene group, a thienylene group, an indolylene group, a quinolylene group, an imidazolinylene group, and a thiazolylene group. In an embodiment of the present application, the substituted or unsubstituted heteroarylene group is a substituted or unsubstituted C2-C 30 that is, the number of carbon atoms in the heteroarylene group is 2 to 30. Specifically, the number of carbon atoms in the heteroarylene group is not limited, but may be 3, 5, 8, 12, 17, 20, 25, 28, or 30.

[0047] In the present application, the fused polycyclic arylene group is a divalent fused polycyclic aryl group. Specifically, the fused polycyclic arylene group may include, but is not limited to, at least one of a naphthylene group, an arylene group, a tetraphenylene group, and a pentaphenylene group. In an embodiment of the present application, the substituted or unsubstituted fused polycyclic arylene group may be a substituted or unsubstituted C 10 ~C 30 That is, the number of carbon atoms in the fused polycyclic arylene group is 10 to 30. Specifically, the number of carbon atoms in the fused polycyclic arylene group is not limited, but may be 10, 15, 18, 20, 25, 28, or 30.

[0048] In this application, a substituted group (such as an aryl group, a heteroaryl group, an alkylene group, an alkenylene group, an alkynylene group, an alicyclylene group, a heteroarylene group, and a fused polycyclic arylene group) refers to a group substituted with a substituent. In one embodiment, the substituent includes at least one of a halogen, a nitrogen atom, an oxygen atom, a sulfur atom, a hydroxyl, a nitro, an amine, a thiol, a methoxy, and a cyano.

[0049] In one embodiment of the present application, Ar 1 and Ar 2 are independently selected from substituted or unsubstituted aryl groups, and R is oxygen, sulfur, sulfone, sulfoxide, carbonyl, or secondary amine. This is beneficial for improving the synthetic efficiency of the catalyst. In one embodiment, Ar 1 and Ar 2 are the same group. In another embodiment, Ar 1 and Ar 2 are different groups. In one embodiment of the present application, the catalyst is represented by the formula (I-1) to the formula (I-5): [ka] The compound includes one of the compounds represented by:

[0050] The present application provides a method for preparing a catalyst for polyimide synthesis, the method comprising:

[0051] A first reactant is provided, the structural formula of the first reactant is shown in formula (II), wherein: 2 is selected from a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; [ka]

[0052] A second reactant is provided, the structural formula of the second reactant being shown in formula (III), wherein: 1is selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, alkylene, alkenylene, alkynylene, alicyclylene group, heteroarylene group, fused polycyclic arylene group, or a single bond; H2N-Ar 1 -R1-Ar 1 -NH2(III);

[0053] The first reactant and the second reactant are mixed, and a catalyst for polyimide synthesis is obtained after the first reaction. The structural formula of the catalyst for polyimide synthesis is Formula (I): [ka] As shown in.

[0054] The method for preparing a catalyst for polyimide synthesis provided in the present application is simple and easy to operate, and can prepare a catalyst with excellent activity, which is beneficial for polyimide synthesis.

[0055] In one embodiment of the present application, the method for preparing the first reactant comprises the steps of: 2 -X to undergo a second reaction to form Ar 2 -MgX, where X is a halogen; 2 The third reaction was carried out with -MgX and diethylamine dichlorophosphorus to give Ar 2 2P(NEt2) and Ar 2 and subjecting the 2P(NEt2) and phosphorus trichloride to a fourth reaction to obtain the first reactant. 2 X in -X is a halogen, and Ar 2 It can be understood that Et in 2P(NEt2) represents an ethyl group.

[0056] In one embodiment of the present application, magnesium Ar 2The molar ratio of magnesium to Ar is 1:(1-1.5), which promotes the second reaction and does not produce by-products. 2 The molar ratio of magnesium to Ar may be, but is not limited to, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, or 1:1.5. In one embodiment, 2 In another embodiment, the molar ratio of magnesium to Ar 2 The molar ratio of -X to -X is 1:(1.2 to 1.5). In another embodiment of the present application, the second reaction involves reacting at 0°C to 80°C for 2 to 48 hours. Specifically, the reaction temperature of the second reaction may be, but is not limited to, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, or 80°C, and the reaction time of the second reaction may be, but is not limited to, 2 hours, 5 hours, 10 hours, 20 hours, 28 hours, 30 hours, 35 hours, 40 hours, 42 hours, 45 hours, or 48 hours. In one embodiment, the second reaction involves reacting at 0°C to 20°C for 2 to 25 hours. In another embodiment, the second reaction involves reacting at 50°C to 80°C for 2 to 20 hours. In yet another embodiment, the second reaction involves reacting at 20°C to 50°C for 5 to 30 hours. In yet another embodiment of the present application, the second reaction is carried out under the action of an initiator, which promotes rapid progress of the second reaction. Specifically, the initiator may include, but is not limited to, at least one of elemental iodine, 1,2-dibromoethane, and a Grignard reagent. In yet another embodiment of the present application, the reaction solvent for the second reaction may include at least one of tetrahydrofuran and diethyl ether.

[0057] In one embodiment of the present application, diethylamine dichlorophosphorus Ar 2 The molar ratio of -X to Ar is 0.3 to 1. Specifically, 2The molar ratio of - to X may be, but is not limited to, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In one embodiment, the molar ratio of diethylamine dichlorophosphorus to Ar 2 The molar ratio of -X to -X is 0.5. In another embodiment of the present application, the third reaction is carried out at 0°C to 30°C for 2 to 18 hours. Specifically, the reaction temperature of the third reaction may be, but is not limited to, 0°C, 10°C, 15°C, 20°C, 25°C, or 30°C, and the reaction time of the third reaction may be, but is not limited to, 2 hours, 5 hours, 10 hours, 12 hours, 15 hours, 17 hours, or 18 hours. In one embodiment, the third reaction is carried out at 0°C to 20°C for 10 to 18 hours. In another embodiment of the present application, saturated ammonium chloride can be used for quenching after the third reaction, and ethyl acetate can be used for extraction. The organic phase is dried over saturated sodium sulfate, concentrated using a rotary evaporator, and then vacuum dried to obtain a HCl-containing solution. 2 2P(NEt2) can be obtained.

[0058] In one embodiment of the present application, Ar of phosphorus trichloride 2 The molar ratio of Ar to 2P(NEt2) is greater than 5, thereby ensuring an excess of phosphorus trichloride. 2 This further ensures that 2P(NEt2) can be completely reacted. In another embodiment of the present application, the fourth reaction includes reacting at 60°C to 80°C for 1 hour to 10 hours. Specifically, the reaction temperature of the fourth reaction may be, but is not limited to, 60°C, 62°C, 65°C, 70°C, 73°C, 75°C, 77°C, or 80°C, and the reaction time of the fourth reaction may be, but is not limited to, 1 hour, 2 hours, 5 hours, 7 hours, 8 hours, or 10 hours. In yet another embodiment of the present application, the fourth reaction is carried out under an inert atmosphere. Specifically, but not limited to, it may be carried out under a nitrogen atmosphere. In another embodiment of the present application, after the fourth reaction, phosphorus trichloride and by-products produced in the reaction may be removed by vacuum distillation to obtain the first reactant.

[0059] In one embodiment of the present application, the second reactant may include at least one of 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, N,N-bis(4-aminophenyl)-1,4-phenylenediamine, and 9,9-bis(4-aminophenyl)fluorene.

[0060] In one embodiment of the present application, the molar ratio of the first reactant to the second reactant is 2 to 3, which contributes to ensuring sufficient reaction. Specifically, the molar ratio of the first reactant to the second reactant may be, but is not limited to, 2:1, 2.2:1, 2.5:1, 2.8:1, 2.9:1, or 3:1. In one embodiment of the present application, the first reaction involves reacting at 25°C to 150°C for 2 to 48 hours. Specifically, the reaction temperature of the first reaction may be, but is not limited to, 25°C, 40°C, 50°C, 65°C, 80°C, 100°C, 125°C, or 150°C. The reaction time of the first reaction may be, but is not limited to, 2 hours, 5 hours, 10 hours, 18 hours, 25 hours, 36 hours, 40 hours, or 48 hours. In one embodiment, the first reaction involves reacting at 25°C to 130°C for 2 hours to 48 hours. In another embodiment, the first reaction involves reacting at 80°C to 130°C for 10 hours to 48 hours. In another embodiment of the present application, after the first reaction, ethyl acetate is used for extraction, and the organic phase is dried with saturated sodium sulfate and then concentrated using a rotary evaporator, and the catalyst can be obtained after recrystallization with ethyl acetate and n-hexane.

[0061] The present application also provides a method for preparing a polyimide, comprising mixing the catalyst of any of the above embodiments with a diamine and a dianhydride, and obtaining a polyimide after a fifth reaction.

[0062] In one embodiment of the present application, the diamine includes at least one of o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 1,3-diamino-2-methylpropane, N,N-bis(4-aminophenyl)-1,4-phenylenediamine, and 9,9-bis(4-aminophenyl)fluorene. In the present application, the two phosphorus skeletons in the diamine and catalyst have similar structures, which promote molecular stacking and help improve the mechanical properties of the polyimide.

[0063] In one embodiment of the present application, the dianhydride comprises at least one of pyromellitic anhydride, 2,3,3',4'-diphenyl ether tetracarboxylic acid anhydride, 3,3',4,4'-tetracarboxybenzophenone dianhydride, 3,3',4,4'-tetracarboxybiphenyl sulfone dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylmethane dianhydride, and 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride.

[0064] In one embodiment of the present application, the molar ratio of diamine, dianhydride, and catalyst is (0.95-1.05):1:(0.0001-0.1). This facilitates rapid preparation of polyimides. The catalysts provided herein have high reactivity and only need to be added in small amounts (only 100 ppm) to effectively catalyze the polyimide preparation. This not only ensures the preparation of polyimides but also does not affect the film-forming properties of the polyimides, benefiting the use of polyimides. Specifically, the molar ratio of diamine, dianhydride, and catalyst may be, but is not limited to, 0.95:1:0.001, 1:1:0.05, 0.98:1:0.0001, 1.01:1:0.07, 1.03:1:0.0045, etc. In one embodiment, the ratio is (0.95-1.05):1:(0.0001-0.001). In another embodiment, the ratio is (0.95 to 1.05):1:(0.001 to 0.01), and in yet another embodiment, the ratio is (0.95 to 1.05):1:(0.01 to 0.1).

[0065] In one embodiment of the present application, the reaction solvent for the fifth reaction may include at least one of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. In one embodiment of the present application, the molar ratio of the diamine, dianhydride, catalyst, and reaction solvent for the fifth reaction may be (0.95-1.05):1:(0.0001-0.1):(25-200). In one embodiment, the molar ratio of the diamine, dianhydride, catalyst, and reaction solvent for the fifth reaction may be (0.95-1.05):1:(0.0001-0.1):(25-85). In another embodiment, the molar ratio of the diamine, dianhydride, catalyst, and reaction solvent for the fifth reaction may be (0.95-1.05):1:(0.0001-0.1):(50-150). In yet another embodiment, the molar ratio of the diamine, the dianhydride, the catalyst, and the reaction solvent for the fifth reaction may be (0.95-1.05):1:(0.0001-0.1):(75-120).

[0066] In one embodiment of the present application, the fifth reaction involves reacting at 60°C to 180°C for 1 hour to 48 hours. Specifically, the reaction temperature of the fifth reaction is not limited to, but may be, for example, 60°C, 70°C, 95°C, 120°C, 140°C, 150°C, 160°C, or 180°C, and the reaction time of the fifth reaction is not limited to, but may be, for example, 2 hours, 5 hours, 10 hours, 18 hours, 25 hours, 36 hours, 40 hours, or 48 hours. In one embodiment, the fifth reaction involves reacting at 60°C to 120°C for 5 hours to 42 hours. In another embodiment, the fifth reaction involves reacting at 85°C to 150°C for 1 hour to 38 hours.

[0067] In one embodiment of the present application, the diamine, catalyst, and reaction solvent for the fifth reaction may be added to a reactor and uniformly stirred and mixed at -20°C to 25°C; then, the dianhydride is slowly added to the reactor, the temperature is raised to 60°C to 180°C, and the reaction is carried out for 1 hour to 48 hours; after the reaction solution is cooled to room temperature, a polar solvent is added to the reaction system, and after filtration and drying, a polyimide is obtained. In one embodiment, the polar solvent includes at least one of methanol, ethanol, and water.

[0068] The present application also provides a polyimide prepared by the above-mentioned method for preparing a polyimide. The polyimide has good film-forming properties and excellent mechanical properties, which are beneficial for its use.

[0069] The technical solutions of the present application are further illustrated below by specific embodiments and comparative examples. [Example]

[0070] In the presence of an iodine initiator, magnesium metal and 4-chloro-N,N-dimethylaniline (1:1 molar ratio) were reacted at 45°C for 6 hours in tetrahydrofuran as a solvent. The solution was cooled to 0°C, diethylamine dichlorophosphorus was added dropwise to the solution (the molar ratio of diethylamine dichlorophosphorus to 4-chloro-N,N-dimethylaniline was 0.5), and the mixture was stirred for 18 hours. The reaction mixture was quenched with saturated ammonium chloride and then extracted with ethyl acetate. The organic phase was dried with saturated sodium sulfate and concentrated using a rotary evaporator. After drying under vacuum, it was reacted with excess phosphorus trichloride under nitrogen protection. The reaction mixture was refluxed for 2 hours, and then phosphorus trichloride and its by-products were removed by distillation under reduced pressure. [ka] obtained.

[0071] The above product and 4,4'-diaminodiphenyl ether (molar ratio 2:1) were stirred in tetrahydrofuran at 25°C for 48 hours, then extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated using a rotary evaporator, and recrystallized with ethyl acetate and n-hexane to obtain a catalyst for polyimide synthesis. The structural formula of the catalyst for polyimide synthesis is shown in Formula (I-1). [Example]

[0072] Under the action of 1,2-dibromoethane initiator, magnesium metal and 4-bromoanisole (molar ratio 1:1) were reacted at 80°C for 18 hours in tetrahydrofuran as a solvent. The solution was cooled to 0°C, diethylamine dichlorophosphorus was added dropwise to the solution (the molar ratio of diethylamine dichlorophosphorus to 4-bromoanisole was 0.5), stirred for 12 hours, quenched with saturated ammonium chloride, and then extracted with ethyl acetate. The organic phase was dried with saturated sodium sulfate and concentrated using a rotary evaporator. After drying in vacuo, it was reacted with excess phosphorus trichloride under nitrogen protection. The reaction solution was refluxed for 2 hours, and then phosphorus trichloride and its by-products were removed by distillation under reduced pressure. [ka] obtained.

[0073] The above product and 4,4'-diaminodiphenyl ether (molar ratio 2:1) were stirred in toluene at 25°C for 2 hours, then extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated using a rotary evaporator, and recrystallized with ethyl acetate and n-hexane to obtain a catalyst for polyimide synthesis. The structural formula of the catalyst for polyimide synthesis is shown in Formula (I-2). [Example]

[0074] Under the action of iodine initiator, magnesium metal and m-bromoanisole (1:1 molar ratio) were reacted at 0°C for 2 hours in ether as a solvent. The solution was cooled to 0°C, diethylamine dichlorophosphorus was added dropwise to the solution (the molar ratio of diethylamine dichlorophosphorus to m-bromoanisole was 0.5), stirred for 18 hours, quenched with saturated ammonium chloride, and then extracted with ethyl acetate. The organic phase was dried with saturated sodium sulfate and concentrated using a rotary evaporator. After drying in vacuo, it was reacted with excess phosphorus trichloride under nitrogen protection. The reaction solution was refluxed for 2 hours, and then phosphorus trichloride and its by-products were removed by distillation under reduced pressure. [ka] obtained.

[0075] The above product and 4,4'-diaminodiphenyl ether (molar ratio 2:1) were stirred in tetrahydrofuran at 80°C for 48 hours, then extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated using a rotary evaporator, and recrystallized with ethyl acetate and n-hexane to obtain a catalyst for polyimide synthesis. The structural formula of the catalyst for polyimide synthesis is shown in Formula (I-3). [Example]

[0076] Under the action of iodine initiator, magnesium metal and 1-bromo-2,4,6-trimethoxybenzene (1:1 molar ratio) were reacted at 0°C for 2 hours in tetrahydrofuran as a solvent. The solution was cooled to 0°C, diethylamine dichlorophosphorus was added dropwise to the solution (the molar ratio of diethylamine dichlorophosphorus to 1-bromo-2,4,6-trimethoxybenzene was 0.5), and the mixture was stirred for 15 hours. The reaction mixture was quenched with saturated ammonium chloride and then extracted with ethyl acetate. The organic phase was dried with saturated sodium sulfate and concentrated using a rotary evaporator. After drying under vacuum, it was reacted with excess phosphorus trichloride under nitrogen protection. The reaction mixture was refluxed for 2 hours, and then phosphorus trichloride and its by-products were removed by distillation under reduced pressure. [ka] obtained.

[0077] The above product and 4,4'-diaminodiphenyl ether (molar ratio 2:1) were stirred in xylene at 130°C for 48 hours, then extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated using a rotary evaporator, and recrystallized with ethyl acetate and n-hexane to obtain a catalyst for polyimide synthesis. The structural formula of the catalyst for polyimide synthesis is shown in Formula (I-4). [Example]

[0078] Under the action of iodine initiator, magnesium metal and 1-bromo-2,4,6-trimethoxybenzene (1:1 molar ratio) were reacted at 0°C for 2 hours in tetrahydrofuran as a solvent. The solution was cooled to 0°C, diethylamine dichlorophosphorus was added dropwise to the solution (the molar ratio of diethylamine dichlorophosphorus to 1-bromo-2,4,6-trimethoxybenzene was 0.5), and the mixture was stirred for 15 hours. The reaction mixture was quenched with saturated ammonium chloride and then extracted with ethyl acetate. The organic phase was dried with saturated sodium sulfate and concentrated using a rotary evaporator. After drying under vacuum, it was reacted with excess phosphorus trichloride under nitrogen protection. The reaction mixture was refluxed for 2 hours, and then phosphorus trichloride and its by-products were removed by distillation under reduced pressure. [ka] obtained.

[0079] The above product and 4,4'-diaminodiphenyl sulfone (molar ratio 2:1) were stirred in xylene at 80°C for 48 hours, then extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated using a rotary evaporator, and recrystallized with ethyl acetate and n-hexane to obtain a catalyst for polyimide synthesis. The structural formula of the catalyst for polyimide synthesis is shown in Formula (I-5). [Example]

[0080] 4 g of 4,4'-diaminodiphenyl ether, 0.0015 g of the catalyst prepared in Example 1, and 190 g of N-methylpyrrolidone were sequentially placed in a reactor, and stirring was started and the temperature was lowered to 0°C; then 6.44 g of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was slowly added to the reactor; the reactor was heated to 120°C and stirred for 36 hours, cooled to room temperature, methanol was added, and the mixture was filtered and dried to obtain a polyimide solid. [Example]

[0081] 4 g of 4,4'-diaminodiphenyl ether, 0.0014 g of the catalyst prepared in Example 2, and 190 g of N-methylpyrrolidone were sequentially placed in a reactor, and stirring was started and the temperature was lowered to 0°C; then 6.44 g of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was slowly added to the reactor; the reactor was heated to 120°C and stirred for 36 hours, cooled to room temperature, added with methanol, and filtered and dried to obtain a polyimide solid. [Example]

[0082] 4 g of 4,4'-diaminodiphenyl ether, 0.0014 g of the catalyst prepared in Example 3, and 190 g of N-methylpyrrolidone were sequentially placed in a reactor, and stirring was started and the temperature was lowered to 0°C; then 6.44 g of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was slowly added to the reactor; the reactor was heated to 120°C and stirred for 36 hours, cooled to room temperature, methanol was added, and the mixture was filtered and dried to obtain a polyimide solid. [Example]

[0083] 4 g of 4,4'-diaminodiphenyl ether, 0.0019 g of the catalyst prepared in Example 4, and 190 g of N-methylpyrrolidone were sequentially placed in a reaction vessel, and stirring was started and the temperature was lowered to 0°C; then 6.44 g of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was slowly added to the vessel; the reaction vessel was heated to 120°C and stirred for 36 hours, cooled to room temperature, methanol was added, and the mixture was filtered and dried to obtain a polyimide solid. [Example]

[0084] 4 g of 4,4'-diaminodiphenyl ether, 0.002 g of the catalyst prepared in Example 5, and 190 g of N-methylpyrrolidone were sequentially added to a reaction vessel, stirring was started, and the temperature was lowered to 0°C; then 6.44 g of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was slowly added to the vessel; the reaction vessel was heated to 120°C and stirred for 36 hours, cooled to room temperature, methanol was added, and the mixture was filtered and dried to obtain a polyimide solid.

[0085] Comparative Example 1 4 g of 4,4'-diaminodiphenyl ether, 0.0015 g of isoquinoline, and 190 g of N-methylpyrrolidone were sequentially added to a reaction vessel, stirring was started, and the temperature was lowered to 0°C; then 6.44 g of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was slowly added to the vessel; the reaction vessel was heated to 120°C and stirred for 36 hours, cooled to room temperature, methanol was added, and the mixture was filtered and dried to obtain a polyimide solid.

[0086] Comparative Example 2 4 g of 4,4'-diaminodiphenyl ether, 0.15 g of isoquinoline, and 190 g of N-methylpyrrolidone were sequentially added to a reaction vessel, stirring was started, and the temperature was lowered to 0°C; then 6.44 g of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was slowly added to the vessel; the reaction vessel was heated to 120°C and stirred for 36 hours, cooled to room temperature, methanol was added, and the mixture was filtered and dried to obtain a polyimide solid.

[0087] Performance Test The structures of the catalysts obtained in Examples 1 to 5 and the polyimide obtained in Comparative Example 1 were characterized by nuclear magnetic resonance, and the results of the hydrogen nuclear magnetic resonance spectra obtained were as follows:

[0088] Example 1: 1H NMR (500MHz, chloroform-d) δ7.35-7.29(m,2H), 6.94-6.88(m,1H), 6.88-6.82(m,1H), 6.72-6.64(m,2H), 2.98(s,4H).

[0089] Example 2: 1H NMR (500 MHz, chloroform-d) δ 7.49-7.42 (m, 1H), 6.94-6.82 (m, 2H), 3.83 (s, 1H).

[0090] Example 3: 1H NMR (500MHz, chloroform-d) δ7.25 (td, J=8.2, 7.5Hz, 1H), 7.17-7.11 (m, 1H), 6.9 4(td,J=2.1,1.3Hz,1H), 6.94-6.88(m,1H), 6.88-6.81(m,2H), 3.82(s,2H).

[0091] Example 4: 1H NMR (500 MHz, chloroform-d) δ 6.94-6.88 (m, 1H), 6.88-6.82 (m, 1H), 6.26 (s, 1H), 3.83 (d, J=16.3 Hz, 7H).

[0092] Example 5: 1H NMR (500 MHz, chloroform-d) δ 7.82-7.76 (m, 1H), 7.13-7.07 (m, 1H), 6.26 (s, 1H), 3.83 (d, J=16.3 Hz, 7H).

[0093] Comparative example 1: 1H NMR (500MHz, THF-d8) δ8.48 (d, J = 1.7 Hz, 1H), 8.39 (d, 2H), 8.24 (d, 1H), 8.15 (ddd, 3H), 8.04 (d, 2H), 7.45-7.39 (m, 4H), 7.15-7.09 (m, 4H).

[0094] The cyclization degree of the products obtained in Examples 6 to 10 and Comparative Examples 1 and 2 was examined by H NMR (500 MHz, DMSO-d). The chemical shift of the uncyclized form was 7.94 ppm, and the chemical shift of the cyclized form was 8.24 ppm. The cyclization degree = integral of the chemical shift of the cyclized form / (integral of the chemical shift of the uncyclized form + integral of the chemical shift of the cyclized form). The test results are shown in Table 1.

[0095] The polyimides prepared in Examples 6-9 and Comparative Examples 1-2 were dissolved in organic solvents and formed into films by roller coating or blade coating; the polyimide prepared in Example 10 was formed into a film by hot pressing using a high-temperature roller. After film formation, the film was cut into dumbbell shapes using a film cutting tool. The edges of the samples were required to be smooth and unbroken. Samples were inspected using a low-power magnifying glass, and samples with defective edges were discarded. In accordance with GB 13022-91, the samples were stretched at a constant speed using a tensile tester. After the sample broke, the required load and the elongation between the corresponding markings were read, and the breaking elongation was calculated. The test results are shown in Table 1.

[0096] [Table 1]

[0097] It can be seen from Table 1 that the polyimides synthesized using the catalysts prepared in Examples 1 to 5 have higher cyclization degrees than the polyimides prepared in Comparative Examples 1 and 2, with the cyclization degree of the polyimide in Example 9 being as high as 94%; at the same time, a large amount of catalyst was added to Comparative Example 2 to improve the cyclization effect of the polyimide, but the residual catalyst affected the elongation at break of the polyimide, while the polyimides synthesized using the catalysts prepared in Examples 1 to 5 had high elongation at break. It was found that the catalysts provided in the present application have high activity even in small amounts, and even if not removed, they do not affect the film-forming properties of the polyimide, which is beneficial for the use of polyimides.

[0098] The above embodiments are merely some implementations of the present application, and although the descriptions thereof are specific and detailed, they should not be construed as limiting the patent scope of the present application. It should be noted that those skilled in the art may make various modifications and improvements without departing from the concept of the present application, and all such modifications and improvements shall fall within the protection scope of the present application. Therefore, the protection scope of the present application should be based on the appended claims.

Claims

1. A catalyst for polyimide synthesis, the structural formula of which is Formula (I): 【Chemistry 1】 As shown in In the formula, Ar １ and Ar ２ are independently selected from a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; R １ is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, alkylene, alkenylene, alkynylene, alicyclylene group, heteroarylene group, fused polycyclic arylene group, or a single bond; Catalyst for polyimide synthesis.

2. The substituted or unsubstituted aryl group is a substituted or unsubstituted C ６ ~C ３０ The catalyst of claim 1, which is an aryl group.

3. The substituted or unsubstituted heteroaryl group is a substituted or unsubstituted C ２ ~C ３０ The catalyst of claim 1 which is a heteroaryl group.

4. The substituted or unsubstituted alkylene is a substituted or unsubstituted C １ ~C ８ The catalyst of claim 1 which is an alkylene.

5. The substituted or unsubstituted alkenylene is a substituted or unsubstituted C ２ ~C ８ The catalyst of claim 1 which is an alkenylene.

6. The substituted or unsubstituted alkynylene is a substituted or unsubstituted C ２ ~C ８ The catalyst of claim 1 which is an alkynylene.

7. The substituted or unsubstituted alicyclylene group is a substituted or unsubstituted C ３ ~C ３０ The catalyst of claim 1 which is an alicyclylene group.

8. The substituted or unsubstituted heteroarylene group is a substituted or unsubstituted C ２ ~C ３０ The catalyst of claim 1 which is a heteroarylene group.

9. The substituted or unsubstituted fused polycyclic arylene group is a substituted or unsubstituted C １０ ~C ３０ The catalyst of claim 1 which is a fused polycyclic arylene group.

10. Ar １ and Ar ２ are independently selected from substituted or unsubstituted aryl groups; R １ 10. The catalyst of claim 1, wherein is oxygen, sulfur, sulfone, sulfoxide, carbonyl, or secondary amine.

11. The catalyst is represented by the formula (I-1) to the formula (I-5): 【Chemistry 2】 11. The catalyst of claim 10, comprising one of the compounds represented by:

12. 1. A method for preparing a catalyst for polyimide synthesis, comprising: A first reactant is provided, the structural formula of the first reactant is shown in formula (II), wherein Ar ２ is selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group; 【Transformation 3】 A second reactant is provided, the structural formula of the second reactant being shown in formula (III), wherein: Ar １ is selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group; R １ is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, alkylene, alkenylene, alkynylene, alicyclylene group, heteroarylene group, fused polycyclic arylene group, or a single bond; and _ ２ ____ １  １ ___ １ H ２ (_=)) The first reactant and the second reactant are mixed, and a catalyst for polyimide synthesis is obtained after the first reaction. The structural formula of the catalyst for polyimide synthesis is formula (I): 【Chemistry 4】 2. A method for preparing a catalyst for polyimide synthesis, as shown in FIG.

13. The preparation method according to claim 12, wherein the molar ratio of the first reactant to the second reactant is 2-3.

14. 14. The method of claim 12 or 13, wherein the first reaction comprises reacting at 25°C to 150°C for 2 hours to 48 hours.

15. The method for preparing the first reactant comprises: Magnesium and Ar ２ -X to undergo a second reaction to give Ar ２ -MgX, where X is a halogen; Ar ２ The third reaction is carried out with MgX and diethylamine dichlorophosphorus to give Ar ２ ２ P(NEt ２ ) and Ar ２ ２ P(NEt ２ ) and phosphorus trichloride to undergo a fourth reaction to obtain the first reactant.

15. The method of any one of claims 12 to 14, comprising:

16. The second reaction comprises reacting at 0°C to 80°C for 2 hours to 48 hours, and ２ The preparation method according to claim 15, wherein the molar ratio of - to X is 1: (1-1.5).

17. The third reaction is carried out at 0°C to 30°C for 2 to 18 hours; and the fourth reaction is carried out at 60°C to 80°C for 1 to 10 hours, and the reaction is carried out by reacting phosphorus trichloride with Ar. ２ ２ P(NEt ２ 17. The method according to claim 15 or 16, wherein the molar ratio of hydroxybenzoate to hydroxybenzoate is greater than 5.

18. The catalyst for polyimide synthesis according to any one of claims 1 to 11 or the catalyst for polyimide synthesis obtained by the preparation method according to any one of claims 12 to 17 is mixed with a diamine and a dianhydride, and a polyimide is obtained after a fifth reaction. A method for preparing a polyimide comprising:

19. The molar ratio of diamine, dianhydride, and catalyst is (0.95-1.05):1:(0.0001-0.1); The fifth reaction comprises reacting at 60°C to 80°C for 1 hour to 48 hours.

20. A method for preparing the polyimide of claim 18.

20. 20. A polyimide prepared by the method of claim 18 or 19.

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