Catalyst for synthesizing polyimide, and preparation method and application thereof

Abstract

The application provides a catalyst for synthesizing polyimide, and a structural formula of the catalyst is shown as formula (I): wherein, Ar 1 , Ar 2 are independently selected from substituted or unsubstituted aryl or substituted or unsubstituted heterocyclic aryl, R1 is oxygen, sulfur, sulfone group, sulfoxide group, carbonyl group, secondary amine group, alkylene group, alkenylene group, alkinylene group, alicyclic group, heterocyclic aryl group, fused ring aryl group or single bond. The catalyst has high reactivity, and a small amount of the catalyst is used in the synthesis of polyimide, so that the film forming property of the polyimide is not affected. The application further provides a preparation method and application of the catalyst for synthesizing polyimide.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyimide, in particular to a catalyst for synthesizing polyimide and a preparation method and application thereof. BACKGROUND

[0002] Polyimide has high mechanical properties, high and low temperature resistance, flame resistance, radiation resistance and other excellent properties, and is widely used in national defense, microelectronics, vehicles, chemical industry and other fields. At present, amine, quinoline or pyridine and other nitrogen-containing compounds are used as catalysts in the synthesis of polyimide. However, nitrogen-containing compounds are easy to react with uncyclized precursors to form salts, which makes it difficult to remove the catalyst, and the residual catalyst will affect the film forming properties of polyimide and reduce the quality of the product. SUMMARY

[0003] Therefore, the present application provides a catalyst for synthesizing polyimide and a preparation method and application thereof. The catalyst has high catalytic activity, and the amount used in the synthesis of polyimide is small, so as not to affect the film forming properties of polyimide.

[0004] In a first aspect, the present application provides a catalyst for synthesizing polyimide, and the structural formula of the catalyst is shown as formula (I):

[0005]

[0006] wherein, Ar 1 , Ar 2 is independently selected from substituted or unsubstituted aryl, or substituted or unsubstituted heterocyclic aryl, R1 is oxygen, sulfur, sulfone group, sulfoxide group, carbonyl group, secondary amine group, alkylene group, alkenylene group, alkynylene group, alicyclic group, heterocyclic aryl group, fused ring aryl group or single bond.

[0007] Optionally, the substituted or unsubstituted aryl is a substituted or unsubstituted C6-C 30 aryl.

[0008] Optionally, the substituted or unsubstituted heterocyclic aryl is a substituted or unsubstituted C2-C 30 heterocyclic aryl.

[0009] Optionally, the substituted or unsubstituted alkylene group is a substituted or unsubstituted C1-C8 alkylene group.

[0010] Optionally, the substituted or unsubstituted alkenylene group is a substituted or unsubstituted C2-C8 alkenylene group.

[0011] Optionally, the substituted or unsubstituted alkynylene group is a substituted or unsubstituted C2-C8 alkynylene group.

[0012] Optionally, the substituted or unsubstituted cycloalkylene group is a substituted or unsubstituted C3-C 30 cycloalkylene group.

[0013] Optionally, the substituted or unsubstituted heterocyclic arylene group is a substituted or unsubstituted C2-C 30 heterocyclic arylene group.

[0014] Optionally, the substituted or unsubstituted fused arylene group is a substituted or unsubstituted C 10 -C 30 fused arylene group.

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

[0016] Optionally, the catalyst comprises one of the compounds shown in formula (I-1) to formula (I-5),

[0017]

[0018]

[0019] The catalyst for synthesizing polyimide provided in the present application has a phosphorus atom, so that the activity of the catalyst is stronger, and the amount used in the synthesis of polyimide is less, so as not to affect the film forming performance of polyimide.

[0020] In a second aspect, the present application provides a preparation method of a catalyst for synthesizing polyimide, comprising:

[0021] providing a first reactant, the structural formula of the first reactant is shown in formula (II), wherein Ar 2 is selected from substituted or unsubstituted aryl groups, or substituted or unsubstituted heterocyclic aryl groups,

[0022]

[0023] providing a second reactant, the structural formula of the second reactant is shown in formula (III), wherein Ar 1 is selected from substituted or unsubstituted aryl groups, or substituted or unsubstituted heterocyclic aryl groups, and the R1 is oxygen, sulfur, sulfone group, sulfoxide group, carbonyl group, secondary amine group, alkylene group, alkenylene group, alkynylene group, cycloalkylene group, heterocyclic arylene group, fused arylene group, or single bond,

[0024] H2N-Ar 1 -R1-Ar1-NH2 (III);

[0025] Mixing the first reactant and the second reactant, after the first reaction, a catalyst for synthesizing polyimide is obtained, and the structural formula of the catalyst for synthesizing polyimide is shown as formula (I):

[0026]

[0027] Optionally, the molar ratio of the first reactant and the second reactant is 2-3.

[0028] Optionally, the first reaction includes reacting at 25℃-150℃ for 2h-48h.

[0029] Optionally, the preparation method of the first reactant includes: magnesium and Ar 2 -X, after the second reaction, Ar is obtained. 2 -MgX, wherein X is halogen; Ar 2 -MgX and diethylamine dichlorophosphorus, after the third reaction, Ar is obtained. 2 2P(NEt2); Ar 2 2P(NEt2) and phosphorus trichloride, after the fourth reaction, the first reactant is obtained.

[0030] Further, the second reaction includes reacting at 0℃-80℃ for 2h-48h.

[0031] Further, the third reaction includes reacting at 0℃-30℃ for 2h-18h.

[0032] Further, the fourth reaction includes reacting at 60℃-80℃ for 1h-10h.

[0033] Further, the molar ratio of the magnesium and the Ar 2 -X is 1:(1-1.5).

[0034] Further, the molar ratio of the phosphorus trichloride and the Ar 2 2P(NEt2) is greater than 5.

[0035] The preparation method of the catalyst for synthesizing polyimide provided in the application is simple, convenient to operate, and can prepare a catalyst with excellent activity, which is conducive to the synthesis of polyimide.

[0036] In a third aspect, the application provides a preparation method of polyimide, including: mixing the catalyst for synthesizing polyimide in the first aspect or the catalyst for synthesizing polyimide prepared by the preparation method in the second aspect with diamine and dianhydride, after the fifth reaction, polyimide is obtained.

[0037] The polyimide provided by the application has simple preparation method, can be prepared by one-step reaction, simple operation, mild conditions, and does not need to remove impurities after reaction, and the product has good performance and good application prospect.

[0038] In a fourth aspect, the application provides a polyimide prepared by the preparation method in the third aspect.

[0039] The polyimide provided by the application has excellent performance, good mechanical properties after film formation, and is beneficial to the use of the polyimide. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the application.

[0041] The application provides a catalyst for synthesizing polyimide, and the structural formula of the catalyst is shown as formula (I):

[0042]

[0043] wherein, Ar 1 , Ar 2 are independently selected from substituted or unsubstituted aryl or substituted or unsubstituted heterocyclic aryl, and R1 is oxygen, sulfur, sulfone group, sulfoxide group, carbonyl group, secondary amine group, alkylene group, alkenylene group, alkynylene group, alicyclic group, heterocyclic aryl group, fused ring aryl group or single bond.

[0044] The catalysts currently used for synthesizing polyimide, such as pyridine or quinoline catalysts, mainly react through the lone pair of electrons in the nitrogen atom. Since nitrogen is a second-period element, its orbital is relatively limited compared with the elements in the same main group, so the relative activity of the lone pair of electrons is weak in the catalytic reaction. The catalyst provided by the application contains phosphorus atoms, and the phosphorus atom has a more expanded orbital than the nitrogen atom, which is beneficial to improving the reaction activity, reducing the required reaction temperature, and promoting the reaction to proceed under more mild conditions, thereby reducing the production cost and improving the production efficiency. In addition, the catalyst provided by the application has high catalytic activity, and the amount used in the synthesis of polyimide is small, and the removal thereof will not affect the film-forming performance of the polyimide, thereby being beneficial to obtaining polyimide with excellent performance.

[0045] In the application, Ar 1 , Ar 2 are independently selected from substituted or unsubstituted aryl or substituted or unsubstituted heterocyclic aryl, that is, Ar 1Ar is selected from substituted aryl, unsubstituted aryl, substituted heterocyclic aryl, or unsubstituted heterocyclic aryl. In the present application, R1is oxygen, sulfur, sulfone group, sulfoxide group, carbonyl group, secondary amine group, alkylene group, alkenylene group, alkynylene group, alicyclic group, heterocyclic aryl group, fused aryl group, or single bond. 2 Ar is selected from substituted aryl, unsubstituted aryl, substituted heterocyclic aryl, or unsubstituted heterocyclic aryl. In the present application, R1is oxygen, sulfur, sulfone group, sulfoxide group, carbonyl group, secondary amine group, alkylene group, alkenylene group, alkynylene group, alicyclic group, heterocyclic aryl group, fused aryl group, or single bond.

[0046] In the present application, aryl is an aromatic group, which can be monocyclic aryl, polycyclic aryl, or fused aryl; monocyclic aryl refers to aryl having only one aromatic ring in the molecule, polycyclic aryl refers to aryl having two or more independent aromatic rings in the molecule, and fused aryl refers to aryl having two or more aromatic rings in the molecule and fused to each other by sharing two adjacent carbon atoms. Specifically, aryl can include, but is not limited to, at least one of phenyl, naphthyl, anthryl, tetracene, pentacene, and tetrahydronaphthyl. In the embodiments of the present application, substituted or unsubstituted aryl is substituted or unsubstituted C6-C 30 aryl; that is, the number of carbon atoms of aryl is 6-30. Specifically, the number of carbon atoms of aryl can include, but is not limited to, 6, 10, 13, 15, 18, 20, 23, 25, 29, or 30.

[0047] In the present application, heterocyclic aryl refers to aryl containing at least one heteroatom, including monocyclic heterocyclic aryl or fused heterocyclic aryl, and the heteroatom is selected from oxygen, sulfur, or nitrogen. Specifically, heteroaryl can include, but is not limited to, at least one of pyridyl, furanyl, thienyl, indolyl, quinolyl, imidazolinyl, and thiazolyl. In the embodiments of the present application, substituted or unsubstituted heterocyclic aryl is substituted or unsubstituted C2-C 30 heterocyclic aryl; that is, the number of carbon atoms of heterocyclic aryl is 2-30. Specifically, the number of carbon atoms of heterocyclic aryl can include, but is not limited to, 3, 5, 8, 10, 12, 15, 18, 20, 25, 27, or 30.

[0048] In the present application, alkylene group is a divalent saturated group formed by removing one hydrogen atom from alkyl. Specifically, alkylene group can include, but is not limited to, at least one of -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, and -CH2CH2CH2CH2CH2CH2-. In the embodiments of the present application, substituted or unsubstituted alkylene group is substituted or unsubstituted C1-C8alkylene group; that is, the number of carbon atoms of alkylene group is 1-8. Specifically, the number of carbon atoms of alkylene group can include, but is not limited to, 1, 2, 3, 4, 5, 6, 7, or 8.

[0049] In the present application, alkenylene is a divalent unsaturated group formed by removing one hydrogen atom from an alkenyl group. Specifically, alkenylene can 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=CHCH2CH2CH2-, -CH=CH-CH=CH2CH2-, and -CH=CH2CH2CH=CH-. In embodiments of the present application, substituted or unsubstituted alkenylene is a substituted or unsubstituted C2-C8 alkenylene; that is, the number of carbon atoms of alkenylene is 2-8. Specifically, the number of carbon atoms of alkenylene can be, but is not limited to, 2, 3, 4, 5, 6, 7, or 8.

[0050] In the present application, alkynylene is a divalent unsaturated group formed by removing one hydrogen atom from an alkynyl group. Specifically, alkynylene can include, but is not limited to, at least one of -C≡C-, -C≡CCH2-, -CH2C≡C-, -C≡CCH2CH2-, -CH2C≡CCH2-, -CH2CH2C≡C-, -C≡C-C≡C-, -C≡CCH2CH2CH2-, -CH2C≡CCH2CH2-, -CH2CH2C≡CCH2-, -CH2C≡C-C≡C-CH2-, -C≡CCH2CH2CH2CH2-, -CH2C≡CCH2CH2CH2-, -CH2CH2C≡CCH2CH2-, -CH2CH2CH2C≡CCH2-, and -CH2CH2CH2CH2C≡C-. In embodiments of the present application, substituted or unsubstituted alkynylene is a substituted or unsubstituted C2-C8 alkynylene; that is, the number of carbon atoms of alkynylene is 2-8. Specifically, the number of carbon atoms of alkynylene can be, but is not limited to, 2, 3, 4, 5, 6, 7, or 8.

[0051] In the present application, cycloalkylene is a divalent cycloalkyl group. Specifically, cycloalkylene can include, but is not limited to, at least one of cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, and cyclopentenyl. In embodiments of the present application, substituted or unsubstituted cycloalkylene is a substituted or unsubstituted C3-C30 cycloalkylene; that is, the number of carbon atoms of cycloalkylene is 3-30. Specifically, the number of carbon atoms of cycloalkylene can be, but is not limited to, 3, 5, 9, 10, 13, 15, 18, 23, 26, or 30. 30

[0052] ​In the present application, a heteroaromatic group is a trivalent heteroaromatic group. Specifically, a heteroaromatic group can include, but is not limited to, at least one of a pyridyl group, a furanyl group, a thiophenyl group, an indolyl group, a quinolyl group, an imidazolyl group, and a thiazolyl group. In an embodiment of the present application, a substituted or unsubstituted heteroaromatic group is a substituted or unsubstituted C 30 heteroaromatic group; that is, the number of carbon atoms in the heteroaromatic group is 2-30. Specifically, the number of carbon atoms in the heteroaromatic group can include, but is not limited to, 3, 5, 8, 12, 17, 20, 25, 28, or 30.

[0053] In the present application, a fused aromatic group is a trivalent fused aromatic group. Specifically, a fused aromatic group can include, but is not limited to, at least one of a naphthyl group, an anthryl group, a tetracenyl group, and a pentacenyl group. In an embodiment of the present application, a substituted or unsubstituted fused aromatic group is a substituted or unsubstituted C 10 -C 30 fused aromatic group; that is, the number of carbon atoms in the fused aromatic group is 10-30. Specifically, the number of carbon atoms in the fused aromatic group can include, but is not limited to, 10, 15, 18, 20, 25, 28, or 30.

[0054] In the present application, a substituted group (such as an aryl group, a heteroaromatic group, an alkylene group, an alkenylene group, an alkynylene group, an alicyclic group, a heteroaromatic group, a fused aromatic group) refers to a group substituted by a substituent. In an embodiment, the substituent includes at least one of a halogen, a nitrogen atom, an oxygen atom, a sulfur atom, a hydroxyl group, a nitro group, an amine group, a mercapto group, a methoxy group, and a cyano group.

[0055] In an embodiment of the present application, Ar 1 , Ar 2 are independently selected from a substituted or unsubstituted aryl group, and R1is an oxygen atom, a sulfur atom, a sulfone group, a sulfoxide group, a carbonyl group, or a secondary amine group. In this way, the synthesis efficiency of the catalyst is improved. In an embodiment, Ar 1 , Ar 2 are the same group. In another embodiment, Ar 1 , Ar 2 are different groups. In an embodiment of the present application, the catalyst includes one of the compounds shown in formulas (I-1) to (I-5),

[0056]

[0057]

[0058] The present application also provides a preparation method of a catalyst for synthesizing a polyimide, including:

[0059] providing a first reactant, the structural formula of the first reactant being shown in formula (II), wherein Ar2 selected from substituted or unsubstituted aryl, or substituted or unsubstituted heterocyclic aryl,

[0060] a second reactant, the structural formula of the second reactant is shown as formula (III), wherein Ar 1 selected from substituted or unsubstituted aryl, or substituted or unsubstituted heterocyclic aryl, R1 is oxygen, sulfur, sulfone group, sulfoxide group, carbonyl group, secondary amine group, alkylene group, alkenylene group, alkynylene group, alicyclic group, heterocyclic aryl group, fused ring aryl group or single bond,

[0061] H2N-Ar 1 -R1-Ar 1 -NH2 (III);

[0062] mixing the first reactant and the second reactant, and obtaining a catalyst for synthesizing polyimide after the first reaction, the structural formula of the catalyst for synthesizing polyimide is shown as formula (I):

[0063]

[0064] The preparation method of the catalyst for synthesizing polyimide provided in the application is simple, convenient to operate, and can prepare a catalyst with excellent activity, which is conducive to the synthesis of polyimide.

[0065] In an embodiment of the application, the preparation method of the first reactant comprises: magnesium and Ar 2 -X are reacted to obtain Ar 2 -MgX, wherein X is halogen; Ar 2 -MgX and diethylamine dichlorophosphine are reacted to obtain Ar 2 2P(NEt2); Ar 2 2P(NEt2) and phosphorus trichloride are reacted to obtain the first reactant. It can be understood that Ar 2 X in -X is halogen, Ar 2 Et in 2P(NEt2) represents ethyl.

[0066] In an embodiment of the application, magnesium and Ar 2 The molar ratio of magnesium and Ar 2 The molar ratio of magnesium and Ar 2 The molar ratio of magnesium and Ar 2The molar ratio of X is 1:(1.2-1.5). In another embodiment of the present application, the second reaction comprises reacting at 0-80°C for 2-48h. Specifically, the reaction temperature of the second reaction can 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, etc., and the reaction time of the second reaction can be but is not limited to 2h, 5h, 10h, 20h, 28h, 30h, 35h, 40h, 42h, 45h or 48h, etc. In an embodiment, the second reaction comprises reacting at 0-20°C for 2-25h. In another embodiment, the second reaction comprises reacting at 50-80°C for 2-20h. In yet another embodiment, the second reaction comprises reacting at 20-50°C for 5-30h. In still another embodiment of the present application, the second reaction is carried out under the action of an initiator, which is conducive to the rapid progress of the second reaction. Specifically, the initiator can be but is not limited to at least one of elemental iodine, 1,2-dibromoethane and Grignard reagent. In still another embodiment of the present application, the reaction solvent of the second reaction can comprise at least one of tetrahydrofuran and diethyl ether.

[0067] In an embodiment of the present application, diethylaminodichlorophosphine and Ar 2 The molar ratio of X is 0.3-1. Specifically, the molar ratio of diethylaminodichlorophosphine to Ar 2 The molar ratio of X can be but is not limited to 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc. In an embodiment, the molar ratio of diethylaminodichlorophosphine to Ar 2 The molar ratio of X is 0.5. In another embodiment of the present application, the third reaction comprises reacting at 0-30°C for 2-18h. Specifically, the reaction temperature of the third reaction can be but is not limited to 0°C, 10°C, 15°C, 20°C, 25°C or 30°C, etc., and the reaction time of the third reaction can be but is not limited to 2h, 5h, 10h, 12h, 15h, 17h or 18h, etc. In an embodiment, the third reaction comprises reacting at 0-20°C for 10-18h. In still another embodiment of the present application, after the third reaction, saturated ammonium chloride can be used for quenching, and ethyl acetate is used for extraction. The organic phase is dried with saturated sodium sulfate, concentrated with a rotary evaporator, and vacuum dried to obtain Ar 2 2P(NEt2).

[0068] In an embodiment of the present application, phosphorus trichloride and Ar 2 The molar ratio of 2P(NEt2) is greater than 5, so as to ensure that phosphorus trichloride is excessive, thereby ensuring that Ar 22P(NEt2) can be reacted completely. In another embodiment of the present application, the fourth reaction includes reacting at 60-80℃ for 1-10h. Specifically, the reaction temperature of the fourth reaction can be but is not limited to 60℃, 62℃, 65℃, 70℃, 73℃, 75℃, 77℃ or 80℃, etc., and the reaction time of the fourth reaction can be but is not limited to 1h, 2h, 5h, 7h, 8h or 10h, etc. In yet another embodiment of the present application, the fourth reaction is carried out under an inert atmosphere. Specifically, it can be but is not limited to carried out under a nitrogen atmosphere. In another embodiment of the present application, after the fourth reaction, the phosphorus trichloride and by-products generated in the reaction can be removed by means of reduced pressure distillation, thereby obtaining the first reactant.

[0069] In an embodiment of the present application, the second reactant can 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.

[0070] In an embodiment of the present application, the molar ratio of the first reactant to the second reactant is 2-3, which is conducive to ensuring sufficient reaction. Specifically, the molar ratio of the first reactant to the second reactant can be but is not limited to 2:1, 2.2:1, 2.5:1, 2.8:1, 2.9:1 or 3:1, etc. In an embodiment of the present application, the first reaction includes reacting at 25-150℃ for 2-48h. Specifically, the reaction temperature of the first reaction can be but is not limited to 25℃, 40℃, 50℃, 65℃, 80℃, 100℃, 125℃ or 150℃, etc., and the reaction time of the first reaction can be but is not limited to 2h, 5h, 10h, 18h, 25h, 36h, 40h or 48h, etc. In an embodiment, the first reaction includes reacting at 25-130℃ for 2-48h. In another embodiment, the first reaction includes reacting at 80-130℃ for 10-48h. In yet another embodiment of the present application, after the first reaction, ethyl acetate is used for extraction, the organic phase is dried with saturated sodium sulfate, and then concentrated by a rotary evaporator. After recrystallization with ethyl acetate and n-hexane, the catalyst can be obtained.

[0071] The present application also provides a preparation method of polyimide, which includes mixing the catalyst of any of the above embodiments with diamine and dianhydride, and obtaining polyimide after a fifth reaction.

[0072] In an 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, 9,9-bis(4-aminophenyl)fluorene. In the present application, the diamine is similar in structure to the two phosphorus skeletons in the catalyst, thereby facilitating the occurrence of molecular stacking and helping to improve the mechanical properties of the polyimide.

[0073] In an embodiment of the present application, the dianhydride includes at least one of pyromellitic dianhydride, 2,3,3',4'-diphenyl ether tetra carboxylic dianhydride, 3,3',4,4'-tetracarboxybenzophenone dianhydride, 3,3',4,4'-tetracarboxy diphenyl 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.

[0074] In an embodiment of the present application, the molar ratio of the diamine, the dianhydride, and the catalyst is (0.95-1.05):1:(0.0001-0.1). This facilitates the rapid preparation of the polyimide. The catalyst provided in the present application has high reactivity, and in the preparation of the polyimide, only a small amount (as low as 100 ppm) needs to be added to play an effective catalytic role, thereby ensuring the preparation of the polyimide and not affecting the film-forming properties of the polyimide, which is conducive to the use of the polyimide. Specifically, the molar ratio of the diamine, the dianhydride, and the catalyst can 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 an embodiment, the molar ratio is (0.95-1.05):1:(0.0001-0.001). In another embodiment, the molar ratio is (0.95-1.05):1:(0.001-0.01). In yet another embodiment, the molar ratio is (0.95-1.05):1:(0.01-0.1).

[0075] In an embodiment of the present application, the reaction solvent of the fifth reaction can include at least one of dimethyl sulfoxide, N-methyl pyrrolidone, N,N-dimethyl formamide and N,N-dimethyl acetamide. In an embodiment of the present application, the molar ratio of the diamine, the dianhydride, the catalyst and the reaction solvent of the fifth reaction can be (0.95-1.05):1:(0.0001-0.1):(25-200). In an embodiment, the molar ratio of the diamine, the dianhydride, the catalyst and the reaction solvent of the fifth reaction can be (0.95-1.05):1:(0.0001-0.1):(25-85). In another embodiment, the molar ratio of the diamine, the dianhydride, the catalyst and the reaction solvent of the fifth reaction can 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 of the fifth reaction can be (0.95-1.05):1:(0.0001-0.1):(75-120).

[0076] In an embodiment of the present application, the fifth reaction includes reacting at 60-180°C for 1-48h. Specifically, the reaction temperature of the fifth reaction can be but is not limited to 60°C, 70°C, 95°C, 120°C, 140°C, 150°C, 160°C or 180°C, etc., and the reaction time of the fifth reaction can be but is not limited to 2h, 5h, 10h, 18h, 25h, 36h, 40h or 48h, etc. In an embodiment, the fifth reaction includes reacting at 60-120°C for 5-42h. In another embodiment, the fifth reaction includes reacting at 85-150°C for 1-38h.

[0077] In an embodiment of the present application, the diamine, the catalyst and the reaction solvent of the fifth reaction can be added into the reaction kettle and stirred uniformly at -20-25°C; then the dianhydride can be slowly added into the reaction kettle, and the temperature can be raised to 60-180°C, and reacted for 1-48h; after the reaction solution is cooled to room temperature, a polar solvent can be added into the reaction system, and the polyimide can be obtained after filtration and drying. In an embodiment, the polar solvent includes at least one of methanol, ethanol and water.

[0078] The present application also provides a polyimide prepared by the above-mentioned method for preparing polyimide. The polyimide has good film-forming property and mechanical property, which is beneficial to its use.

[0079] The technical solutions of the present application are further described below through specific examples and comparative examples.

[0080] Example 1

[0081] In the presence of iodine initiator, magnesium and 4-chloro-N,N-dimethylaniline (molar ratio 1:1) were reacted in tetrahydrofuran as solvent at 45℃ for 6h, then the solution was cooled to 0℃, and diethyl phosphorus dichloride (molar ratio of diethyl phosphorus dichloride to 4-chloro-N,N-dimethylaniline was 0.5) was added dropwise into the solution, stirred for 18h, then quenched with saturated ammonium chloride, extracted with ethyl acetate, the organic phase was dried with saturated sodium sulfate, concentrated by rotary evaporator, vacuum dried, reacted with excess phosphorus trichloride under nitrogen protection, refluxed for 2h, then removed phosphorus trichloride and by-products by vacuum distillation, to obtain

[0082] The above product was stirred with 4,4'-diaminodiphenyl ether (molar ratio 2:1) in tetrahydrofuran at 25℃ for 48h, then extracted with ethyl acetate, the organic phase was dried with saturated sodium sulfate, concentrated by rotary evaporator, recrystallized with ethyl acetate and n-hexane to obtain a catalyst for synthesizing polyimide, and the structural formula of the catalyst for synthesizing polyimide is shown as formula (I-1).

[0083] Example 2

[0084] In the presence of 1,2-dibromoethane initiator, magnesium and 4-bromoanisole (molar ratio 1:1) were reacted in tetrahydrofuran as solvent at 80℃ for 18h, then the solution was cooled to 0℃, and diethyl phosphorus dichloride (molar ratio of diethyl phosphorus dichloride to 4-bromoanisole was 0.5) was added dropwise into the solution, stirred for 12h, then quenched with saturated ammonium chloride, extracted with ethyl acetate, the organic phase was dried with saturated sodium sulfate, concentrated by rotary evaporator, vacuum dried, reacted with excess phosphorus trichloride under nitrogen protection, refluxed for 2h, then removed phosphorus trichloride and by-products by vacuum distillation, to obtain

[0085] The above product was stirred with 4,4'-diaminodiphenyl ether (molar ratio 2:1) in toluene at 25℃ for 2h, then extracted with ethyl acetate, the organic phase was dried with saturated sodium sulfate, concentrated by rotary evaporator, recrystallized with ethyl acetate and n-hexane to obtain a catalyst for synthesizing polyimide, and the structural formula of the catalyst for synthesizing polyimide is shown as formula (I-2).

[0086] Example 3

[0087] In the presence of iodine initiator, magnesium metal was reacted with 1-bromo-2,4,6-trimethoxybenzene (molar ratio 1:1) in tetrahydrofuran as solvent at 0°C for 2h, then the solution was cooled to 0°C, and diethyl phosphorochloridite (molar ratio of diethyl phosphorochloridite to 1-bromo-2,4,6-trimethoxybenzene was 0.5) was added dropwise into the solution, stirred for 15h, then quenched with saturated ammonium chloride, extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated by rotary evaporator, vacuum dried, then reacted with excess phosphorus trichloride under nitrogen protection, refluxed for 2h, then removed phosphorus trichloride and its by-products by vacuum distillation, to obtain

[0088] The above product was stirred with 4,4'-diaminodiphenyl ether (molar ratio 2:1) in tetrahydrofuran at 80°C for 48h, then extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated by rotary evaporator, recrystallized from ethyl acetate and n-hexane to obtain a catalyst for synthesizing polyimide, and the structural formula of the catalyst for synthesizing polyimide is shown as formula (I-3).

[0089] Example 4

[0090] In the presence of iodine initiator, magnesium metal was reacted with 1-bromo-2,4,6-trimethoxybenzene (molar ratio 1:1) in tetrahydrofuran as solvent at 0°C for 2h, then the solution was cooled to 0°C, and diethyl phosphorochloridite (molar ratio of diethyl phosphorochloridite to 1-bromo-2,4,6-trimethoxybenzene was 0.5) was added dropwise into the solution, stirred for 15h, then quenched with saturated ammonium chloride, extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated by rotary evaporator, vacuum dried, then reacted with excess phosphorus trichloride under nitrogen protection, refluxed for 2h, then removed phosphorus trichloride and its by-products by vacuum distillation, to obtain

[0091] The above product was stirred with 4,4'-diaminodiphenyl ether (molar ratio 2:1) in tetrahydrofuran at 80°C for 48h, then extracted with ethyl acetate, the organic phase was dried over saturated sodium sulfate, concentrated by rotary evaporator, recrystallized from ethyl acetate and n-hexane to obtain a catalyst for synthesizing polyimide, and the structural formula of the catalyst for synthesizing polyimide is shown as formula (I-3).

[0092] Example 5

[0093] In the presence of iodine initiator, magnesium and 1-bromo-2,4,6-trimethoxybenzene (molar ratio of 1:1) were reacted at 0℃ for 2h in tetrahydrofuran as solvent, then the solution was cooled to 0℃, and diethyl phosphorus dichloride (molar ratio of diethyl phosphorus dichloride to 1-bromo-2,4,6-trimethoxybenzene was 0.5) was added dropwise into the solution, stirred for 15h, then quenched with saturated ammonium chloride, extracted with ethyl acetate, the organic phase was dried with saturated sodium sulfate, concentrated by rotary evaporator, vacuum dried, reacted with excess phosphorus trichloride under nitrogen protection, the reaction was refluxed for 2h, then phosphorus trichloride and its by-products were removed by distillation under reduced pressure, to obtain

[0094] The above product was stirred with 4,4'-diaminodiphenyl sulfone (molar ratio of 2:1) in xylene at 80℃ for 48h, then extracted with ethyl acetate, the organic phase was dried with saturated sodium sulfate, concentrated by rotary evaporator, recrystallized with ethyl acetate and n-hexane to obtain a catalyst for synthesizing polyimide, and the structural formula of the catalyst for synthesizing polyimide is shown as formula (I-5).

[0095] Example 6

[0096] 4g of 4,4'-diamino diphenyl ether, 0.0015g of the catalyst prepared in Example 1, and 190g of N-methyl pyrrolidone were sequentially put into a reaction kettle, stirring was started and the temperature was lowered to 0℃; then 6.44g of 3,3',4,4'-benzophenone tetracarboxylic dianhydride was slowly added into the kettle; the reaction kettle was heated to 120℃, and after stirring for 36h, the temperature was lowered to room temperature and methanol was added, the polyimide solid was obtained after filtration and drying.

[0097] Example 7

[0098] 4g of 4,4'-diamino diphenyl ether, 0.0014g of the catalyst prepared in Example 2, and 190g of N-methyl pyrrolidone were sequentially put into a reaction kettle, stirring was started and the temperature was lowered to 0℃; then 6.44g of 3,3',4,4'-benzophenone tetracarboxylic dianhydride was slowly added into the kettle; the reaction kettle was heated to 120℃, and after stirring for 36h, the temperature was lowered to room temperature and methanol was added, the polyimide solid was obtained after filtration and drying.

[0099] Example 8

[0100] 4g of 4,4'-diamino diphenyl ether, 0.0014g of the catalyst prepared in Example 3, and 190g of N-methyl pyrrolidone were sequentially put into a reaction kettle, stirring was started and the temperature was lowered to 0℃; then 6.44g of 3,3',4,4'-benzophenone tetracarboxylic dianhydride was slowly added into the kettle; the reaction kettle was heated to 120℃, and after stirring for 36h, the temperature was lowered to room temperature and methanol was added, the polyimide solid was obtained after filtration and drying.

[0101] Example 9

[0102] Into a reaction kettle, 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 added, 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 into the kettle; the reaction kettle was heated to 120°C, and after stirring for 36 h, the temperature was lowered to room temperature and methanol was added, and the polyimide solid was obtained after filtration and drying.

[0103] Example 10

[0104] Into a reaction kettle, 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, 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 into the kettle; the reaction kettle was heated to 120°C, and after stirring for 36 h, the temperature was lowered to room temperature and methanol was added, and the polyimide solid was obtained after filtration and drying.

[0105] Comparative Example 1

[0106] Into a reaction kettle, 4 g of 4,4'-diaminodiphenyl ether, 0.0015 g of isoquinoline, and 190 g of N-methylpyrrolidone were sequentially added, 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 into the kettle; the reaction kettle was heated to 120°C, and after stirring for 36 h, the temperature was lowered to room temperature and methanol was added, and the polyimide solid was obtained after filtration and drying.

[0107] Comparative Example 2

[0108] Into a reaction kettle, 4 g of 4,4'-diaminodiphenyl ether, 0.15 g of isoquinoline, and 190 g of N-methylpyrrolidone were sequentially added, 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 into the kettle; the reaction kettle was heated to 120°C, and after stirring for 36 h, the temperature was lowered to room temperature and methanol was added, and the polyimide solid was obtained after filtration and drying.

[0109] Performance detection

[0110] The structures of the catalysts obtained in Examples 1-5 and the polyimide prepared in Comparative Example 1 were characterized by nuclear magnetic resonance, and the obtained nuclear magnetic resonance hydrogen spectrum results were as follows:

[0111] Example 1: 1H NMR (500 MHz, Chloroform-d) δ 7.35 - 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).

[0112] 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).

[0113] Example 3: 1H NMR (500 MHz, Chloroform-d) δ 7.25 (td, J = 8.2, 7.5 Hz, 1H), 7.17 - 7.11 (m, 1H), 6.94 (td, J = 2.1, 1.3 Hz, 1H), 6.94 - 6.88 (m, 1H), 6.88 - 6.81 (m, 2H), 3.82 (s, 2H).

[0114] 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).

[0115] 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).

[0116] Comparative Example 1: 1H NMR (500 MHz, THF-d8) δ 8.48 (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).

[0117] The degree of cyclization of the products obtained in Examples 6-10 and Comparative Examples 1-2 was tested by nuclear magnetic resonance hydrogen spectrum (500 MHz, DMSO-d6). The uncyclized chemical shift is 7.94 ppm, the cyclized chemical shift is 8.24 ppm, the degree of cyclization = cyclized chemical shift integral / (uncyclized chemical shift integral + cyclized chemical shift integral), and the test results are shown in Table 1.

[0118] The polyimides prepared in Examples 6-9 and Comparative Examples 1-2 were dissolved in organic solvents and formed films by roll coating or blade coating. The polyimide prepared in Example 10 was formed into a film by hot pressing with a hot roller. After film formation, the film was cut into dumbbell shapes with a film cutter. The edges of the samples were smoothed and no defects were allowed. The samples were examined under a low-power magnifying glass and samples with defective edges were discarded. According to GB 13022-91, the samples were stretched at a constant speed using a tensile testing machine. The load and the corresponding gauge length elongation were read after the sample broke, and the elongation at break was calculated. The test results are shown in Table 1.

[0119] Table 1 Test Results

[0120] Degree of cyclization / % Elongation at break / % Example 6 68 32 Example 7 72 34 Example 8 59 32 Example 9 94 31 Example 10 89 30 Comparative Example 1 38 33 Comparative Example 2 65 16

[0121] As can be seen from Table 1, compared with the polyimide prepared in Comparative Example 1-2, the polyimides prepared in Examples 1-5 using the catalysts have a higher cyclization degree, and the cyclization degree of the polyimide in Example 9 is as high as 94%. In Comparative Example 2, a large amount of catalyst was added to improve the cyclization effect of the polyimide, but the residual catalyst affected the elongation at break of the polyimide. The polyimides prepared in Examples 1-5 using the catalysts have a high elongation at break. It can be seen that the catalysts provided in the present application have high activity and are used in small amounts, and even if they are not removed, they will not affect the film-forming properties of the polyimide, which is conducive to the use of the polyimide.

[0122] The above-described examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application should be subject to the appended claims.

Claims

1. A catalyst for the synthesis of polyimides, characterized in that, The structural formula of the catalyst is shown as formula (I): wherein Ar 1 , Ar 2 is independently selected from substituted or unsubstituted aryl, or substituted or unsubstituted heterocyclic aryl, and R1is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, C2-C8alkylene, alkenylene, alkynylene, cycloalkylene, heterocyclic arylene, fused arylene, or a single bond.

2. The catalyst of claim 1, wherein The substituted or unsubstituted aryl group is a substituted or unsubstituted C6-C 30 aryl group; The substituted or unsubstituted heterocyclic aryl is a substituted or unsubstituted C2-C 30 heterocyclic aryl; The alkenylene group is a substituted or unsubstituted C2-C8 alkenylene group; The alkynylene group is a substituted or unsubstituted C2-C8 alkynylene group; said cycloalkyl group is a substituted or unsubstituted C3-Ci0cycloalkyl group; 30 said cycloalkyl group is a substituted or unsubstituted C3-Ci0cycloalkyl group; said heterocyclylene is a substituted or unsubstituted C2-C 30 heterocyclylene; said heteroaromatic group is a substituted or unsubstituted 5- to 10-membered 10 -C 30 heteroaromatic group.

3. The catalyst of claim 1, wherein said Ar 1 , said Ar 2 is independently selected from substituted or unsubstituted aryl, said R1is oxygen, sulfur, sulfone, sulfoxide, carbonyl, or secondary amine.

4. The catalyst of claim 3, wherein The catalyst comprises one of the compounds shown as formula (I-1) to formula (I-5), 5. A process for the preparation of a catalyst for the synthesis of polyimides according to any one of claims 1 to 4, characterized in that Comprising: A first reactant is provided, the first reactant having a structural formula as shown in Formula (II), wherein Ar 2 is selected from substituted or unsubstituted aryl, or substituted or unsubstituted heterocyclic aryl, a second reactant having a formula as shown in formula (III) wherein Ar 1 R1is selected from substituted or unsubstituted aryl, or substituted or unsubstituted heterocyclic aryl, R1is oxygen, sulfur, sulfone, sulfoxide, carbonyl, secondary amine, C2-C8alkylene, alkenylene, alkynylene, cycloalkylene, heterocyclic arylene, fused arylene, or a single bond, H2N-Ar 1 -R1-Ar 1 -NH2 (III); Mixing the first reactant and the second reactant to obtain a catalyst for synthesizing polyimide after a first reaction, the structural formula of the catalyst for synthesizing polyimide is shown as formula (I):

6. The production method according to claim 5, wherein The molar ratio of the first reactant to the second reactant is 2-3; The first reaction includes reacting at 25-150℃ for 2-48h.

7. The production method according to claim 5, wherein The preparation method of the first reactant comprises: Magnesium and Ar 2 - X is reacted to obtain Ar 2 - MgX, wherein X is halogen; Ar 2 -MgX with diethylamine dichlorophosphor via a third reaction to obtain Ar 2 2P(NEt2); Ar 2 2P(NEt2) with phosphorus trichloride via a fourth reaction to obtain the first reactant.

8. The production method according to claim 7, wherein The second reaction includes reacting at 0-80℃ for 2-48h; The third reaction includes reacting at 0-30℃ for 2-18h; The fourth reaction includes reacting at 60-80℃ for 1-10h; said magnesium and said Ar 2 the molar ratio of X is 1 : (1-1.5); said phosphorus trichloride and said Ar 2 2the molar ratio of P(NEt2) is greater than 5.

9. A method for producing a polyimide, characterized by, Comprising: Mixing the catalyst for synthesizing polyimide according to any one of claims 1-4 or the catalyst for synthesizing polyimide prepared by the preparation method according to any one of claims 5-8 with diamine and dianhydride to obtain polyimide after a fifth reaction.

10. The method of producing a polyimide according to claim 9, wherein The molar ratio of the diamine, the dianhydride and the catalyst is (0.95-1.05):1:(0.0001-0.1); The fifth reaction includes reacting at 60-180℃ for 1-48h.

11. A polyimide, characterized by, Prepared by the preparation method according to any one of claims 9-10.

Images