A method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride

Abstract

The application discloses a preparation method of 2,2'-di(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride, which comprises the following steps: ① iodization reaction of o-xylene to obtain 1,2-diiodo-4,5-xylene; ② coupling reaction of the product of step ① to obtain 2,2'-diiodo-4,4',5,5'-tetramethyl biphenyl; ③ trifluoromethylation of the product of step ② to obtain 2,2'-di(trifluoromethyl)-4,4',5,5'-tetramethyl biphenyl; ④ oxidation of the product of step ③ with an oxidant to obtain 2,2'-di(trifluoromethyl)-4,4',5,5'-biphenyl tetraacid; and ⑤ dehydration and cyclization of the product of step ④ to obtain 2,2'-di(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride. The synthetic route provided by the application has the advantages of mild reaction condition, simple treatment, high efficiency and low cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride. BACKGROUND

[0002] Fluorine-containing polyimide has low dielectric constant, good solubility, excellent optical performance, low moisture absorption rate, corrosion resistance, radiation resistance, high and low temperature resistance, excellent mechanical properties, good adhesion, and the like, and is widely used in the fields of electronics and electric power, OLED, aerospace, precision machinery and the like, becomes an irreplaceable high-performance polymer material, and has high development value. Therefore, it is necessary to develop new technologies to prepare fluorine-containing dianhydride monomers to meet the development needs of fluorine-containing polyimide industry.

[0003] 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride is a white solid powder with a melting point of 209-211 DEG C. The molecular formula is C 18 H4F6O6, and the relative molecular weight is 430.2144.

[0004] There are three kinds of preparation methods of 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride disclosed in the prior art.

[0005] Document 1 discloses a method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride by using 1-iodo-4,5-dimethyl-2-nitrobenzene as a starting material and through six-step reactions.

[0006] The method has the disadvantages of high cost of raw materials, low synthesis yield, high production cost, harsh reaction conditions, and unsuitability for industrialization.

[0007] Document 2 discloses a method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride by using 3,3',4,4'-tetramethylbiphenyl as a starting material and through four-step reactions.

[0008] The method has the disadvantages of difficulty in preparation of the starting material 3,3',4,4'-tetramethylbiphenyl, high price, unsuitability for large-scale industrialization, high reaction temperature (150-170 DEG C) in the introduction of trifluoromethyl, high energy consumption, release of a large amount of CO2, and high danger degree, and unsuitability for large-scale industrial production.

[0009] Document 3 discloses a method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride by using 2,4-dichlorobenzotrifluoride as a starting material and through four-step reactions.

[0010] The method has the following disadvantages: a large amount of thionyl chloride (SOCl2) is used in the first step, the post-treatment is troublesome, and the environmental pollution is serious. In addition, palladium-carbon is used as a catalyst during coupling, which is expensive and has high cost in large-scale industrial production.

[0011] Document 1: sheng-Hsien Lin et al., "Organo-Soluble Polyimides: Synthesis and Polymerization of 2,2'-Bis(trifluoromethyl)-4,4',5,5'-Biphenyltetracarboxylic Dianhydride" Macromolecules 1998, Vol. 31, No. 7, pp. 2080-2086.

[0012] Document 2: Chinese Patent Document CN106699709A, published on May 24, 2017.

[0013] Document 3: Chinese Patent Document CN114539194A, published on May 27, 2022. SUMMARY

[0014] The purpose of the present application is to solve the problems of high cost, low yield and high risk of the above technical solutions, and to provide a preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride which is efficient, convenient and suitable for large-scale industrial production.

[0015] The present application mainly solves the above technical problems through the following technical solutions.

[0016] The present application provides a preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride, which comprises the following steps:

[0017] ① In the presence of an acid and a solvent, o-xylene is iodized with an iodizing reagent to obtain 1,2-diiodo-4,5-dimethylbenzene;

[0018]

[0019] ② In a solvent, 1,2-diiodo-4,5-dimethylbenzene undergoes a coupling reaction in the presence of a base to obtain 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl;

[0020]

[0021] ③ A: polar solvent, CuX, MF and TMSCF3 (trifluoromethyltrimethylsilane) are mixed to obtain a mixed solution 1;

[0022] B: adding 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl to the above mixed solution 1 to obtain 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl;

[0023]

[0024] IV. oxidizing 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl with an oxidizing agent in the presence of a solvent to obtain 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid;

[0025]

[0026] V. dehydrating and cyclizing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid obtained in step IV to obtain 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride;

[0027]

[0028] In some embodiments, in step I, the acid is an inorganic acid, such as concentrated sulfuric acid;

[0029] In some embodiments, in step I, the iodinating agent is iodine and / or periodic acid; for example, iodine mixed with periodic acid;

[0030] In some embodiments, in step I, the solvent is a mixed solvent of a water-soluble organic solvent and water, such as acetic acid: water = 5:1;

[0031] In some embodiments, in step I, the molar ratio of o-xylene to the acid is 1:0.1-1:0.4, preferably 1:0.15-1:0.45, preferably 1:0.33;

[0032] In some embodiments, in step I, the molar ratio of o-xylene to iodine is 1:0.8-1:1.2, preferably 1:0.9;

[0033] In some embodiments, in step I, the molar ratio of o-xylene to periodic acid is 1:0.2-1:0.6, preferably 1:0.4;

[0034] In some embodiments, in step I, the reaction temperature is 0-100°C, preferably 50-80°C, further preferably 70°C;

[0035] In some embodiments, in step ①, the iodination reaction further comprises the following steps: adding the acid and the solvent under nitrogen protection, stirring, then adding o-xylene and the iodination reagent, slowly heating to the reaction temperature, and reacting to obtain 1,2-diiodo-4,5-dimethylbenzene.

[0036] In some embodiments, in step ①, the reaction material is composed of the acid, the iodination reagent, the o-xylene and the solvent

[0037] In some embodiments, in step ②, the base is an alkyl lithium reagent, preferably n-butyllithium, more preferably n-butyllithium in n-hexane;

[0038] In some embodiments, in step ②, the solvent is a cyclic ether solvent, preferably tetrahydrofuran;

[0039] In some embodiments, in step ②, the reaction temperature is -100 to -30℃, preferably -80 to -50℃, and more preferably -78℃.

[0040] In some embodiments, in step ②, the molar ratio of the 1,2-diiodo-4,5-dimethylbenzene to the base is 1:0.4 to 1:0.5, preferably 1:0.45 to 1:0.55, and more preferably 1:0.5;

[0041] In some embodiments, in step ②, the coupling reaction further comprises the following steps: dissolving the 1,2-diiodo-4,5-dimethylbenzene in dry solvent under nitrogen protection, then reducing the temperature of the system, slowly adding the base dropwise, and continuing to react after the addition is completed to obtain the 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl.

[0042] In some embodiments, in step ②, the reaction material is composed of the solvent, the 1,2-diiodo-4,5-dimethylbenzene and the base

[0043] In some embodiments, in step ③, step A, the CuX is CuCl, CuBr, Cul, CuSCN or CuOTf, preferably CuCl;

[0044] In some embodiments, in step ③, step A, the MF is NaF, KF or CsF, preferably KF;

[0045] In some embodiments, in step ③, step A, the polar solvent is DMF, DMSO or NMP, preferably DMF;

[0046] In some embodiments, in step ③, step A, the reaction temperature is 10 to 40℃, preferably 20 to 30℃;

[0047] In some embodiments, in step ③, in step A, after adding dry MF to the dry polar solvent, and activating the CuX, the TMSCF3 is slowly added dropwise to obtain a mixed solution 1 under nitrogen protection.

[0048] In some embodiments, in step ③, in step A, the molar ratio of the TMSCF3 to the CuX is 1:0.5-1:3, preferably 1:0.8-1:1.1, preferably 1:0.91.

[0049] In some embodiments, in step ③, in step A, the molar ratio of the TMSCF3 to the MF is 1:0.5-1:3, preferably 1:0.9-1:1.2, preferably 1:1.

[0050] In some embodiments, in step ③, in step B, the reaction temperature is 0-150°C, preferably 90-120°C, further preferably 115°C.

[0051] In some embodiments, in step ③, in step B, the reaction further comprises the following specific steps: adding 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl to the mixed solution 1 of step A to obtain the 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl.

[0052] In some embodiments, in step ③, in step B, the molar ratio of the TMSCF3 to the 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl is 1:0.1-1:3, preferably 1:0.1-1:0.2, further preferably 1:0.18.

[0053] In some embodiments, in step ③, in step A, the reaction material is composed of the polar solvent, the CuX, the MF, and the TMSCF3.

[0054] In some embodiments, in step ③, in step B, the reaction material is composed of the mixed solution and the 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl.

[0055] In some embodiments, in step ④, the oxidation reaction further comprises the following steps: under nitrogen protection, adding the 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl and the solvent, heating, adding the oxidizing agent, and constant temperature reaction to obtain 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid.

[0056] In some embodiments, in step IV, the oxidizing agent can be an oxidizing agent conventional in the art for such reactions, such as potassium permanganate, sodium dichromate, potassium dichromate or nitric acid, preferably potassium permanganate or 25% nitric acid;

[0057] In some embodiments, in step IV, when the oxidizing agent is potassium permanganate, sodium dichromate or potassium dichromate, the reaction can further comprise a base, which is sodium hydroxide or pyridine, preferably sodium hydroxide;

[0058] In some embodiments, in step IV, the molar ratio of the 2,2’-bis(trifluoromethyl)-4,4’,5,5’-tetramethylbiphenyl to the oxidizing agent is 1:10-1:20, preferably 1:13-1:18, further preferably 1:13 or 1:18;

[0059] In some embodiments, in step IV, the molar ratio of the 2,2’-bis(trifluoromethyl)-4,4’,5,5’-tetramethylbiphenyl to the base is 1:5-1:15, preferably 1:8-1:12, further preferably 1:8.3;

[0060] In some embodiments, in step IV, the reaction temperature is 80-200°C, preferably 90-170°C, further preferably 90°C or 170°C;

[0061] In some embodiments, in step IV, the oxidation reaction further comprises the following steps: under nitrogen protection, adding the 2,2’-bis(trifluoromethyl)-4,4’,5,5’-tetramethylbiphenyl and the solvent, heating, adding the oxidizing agent, constant temperature reaction, filtering while hot, washing the insoluble solid filtered with hot water several times, combining the filtrate, rotary evaporation to obtain a solid. Adding the solvent and the base to the solid to form a solution, heating, continuously reacting by adding the oxidizing agent in batches to obtain 2,2’-bis(trifluoromethyl)-4,4’,5,5’-biphenyltetraoic acid.

[0062] In some embodiments, in step IV, the reaction material consists of the following substances, which are scheme one or scheme two;

[0063] Scheme one: the reaction material consists of the following substances: the 2,2’-bis(trifluoromethyl)-4,4’,5,5’-tetramethylbiphenyl, the solvent and the oxidizing agent;

[0064] Scheme two: the reaction material consists of the following substances: the 2,2’-bis(trifluoromethyl)-4,4’,5,5’-tetramethylbiphenyl, the solvent, the base and the oxidizing agent.

[0065] The present application also provides a preparation method of 2,2’-bis(trifluoromethyl)-4,4’,5,5’-tetramethylbiphenyl, which comprises the following steps:

[0066] A polar solvent, CuX, MF and TMSCF3(trifluoromethyltrimethylsilane) are mixed to obtain a mixed solution 1;

[0067] B 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl is added to the above mixed solution 1 to obtain 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl;

[0068]

[0069] In some embodiments, in the preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step A, the CuX is CuCl, CuBr, Cul, CuSCN or CuOTf, preferably CuCl.

[0070] In some embodiments, the CuX is subjected to an activation treatment, and the activation treatment comprises the following steps: dissolving CuX in acid, diluting with water to precipitate, filtering, washing, drying, storing in the dark and protecting with a protective gas.

[0071] In some embodiments, in the preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step A, the MF is NaF, KF or CsF, preferably KF.

[0072] In some embodiments, in the preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step A, the polar solvent can be a polar solvent commonly used in the reaction in the art, such as DMF, DMSO or NMP, preferably DMF.

[0073] In some embodiments, in the preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step A, the reaction temperature is 10-40°C, preferably 20-30°C.

[0074] In some embodiments, in the preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step B, the reaction temperature is 0-150°C, preferably 90-120°C, and further preferably 115°C.

[0075] In some embodiments, in the preparation method of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step A, the reaction material is the TMSCF, the MF and the CuX.

[0076] In some embodiments, in step B, the reactant is the mixed solution 1 obtained in step A and 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl.

[0077] In some embodiments, in step A, the MF is anhydrous MF.

[0078] In some embodiments, in the method for preparing 2,2'-di(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step A, the reaction further comprises the following specific steps: adding dry MF into dry polar solvent under nitrogen protection, and after the activated CuX is treated, slowly adding TMSCF3, to obtain 2,2'-di(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl.

[0079] In some embodiments, in the method for preparing 2,2'-di(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step B, the reaction further comprises the following specific steps: adding 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl into the reaction solution of step A to obtain 2,2'-di(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl.

[0080] In some embodiments, in the method for preparing 2,2'-di(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step A, the molar ratio of TMSCF3 to CuX is 1:0.5-1:3, preferably 1:0.8-1:1.1, and further preferably 1:0.9.

[0081] In some embodiments, in the method for preparing 2,2'-di(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, in step A, the molar ratio of TMSCF3 to MF is 1:0.5-1:3, preferably 1:0.9-1:1.2, and further preferably 1:1.

[0082] In some embodiments, in the method for preparing 2,2'-di(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, the molar ratio of TMSCF3 to 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl is 1:0.1-1:3, preferably 1:0.1-1:0.2, and further preferably 1:0.18.

[0083] In some embodiments, in the method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, the progress of the reaction can be detected by using conventional monitoring methods in the art (e.g. TLC, HPLC or NMR), and the reaction is generally terminated when the 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl disappears or no longer reacts, or when the 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl no longer increases. For example, the reaction time can be 14-20 hours.

[0084] In some embodiments, in the method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, the reaction further comprises the following post-treatment step: after the reaction is completed, the reaction solution is filtered to remove insoluble substances, the insoluble substances are washed with a small amount of ethyl acetate, then the filtrate is rotary evaporated to obtain a solid, which is then soaked and washed with a large amount of PE / EA (volume ratio 10:1) mixed solvent, the washing liquid is washed with saturated brine, dried with anhydrous sodium sulfate, filtered, concentrated and dried to obtain 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl.

[0085] Unless otherwise specified, the terms used in the present application have the following meanings:

[0086] The term "alkyl" refers to straight-chain or branched-chain alkyl groups having a specified number of carbon atoms (e.g. C1-C6). Alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, etc.

[0087] The term "halogen" refers to fluorine, chlorine, bromine or iodine, which is abbreviated as X in the chemical formula.

[0088] The term "MF" refers to metal fluoride of metal elements, including but not limited to NaF, KF and CsF.

[0089] On the basis of common sense in the art, the above-mentioned preferred conditions can be combined arbitrarily, i.e. to obtain each preferred example of the present application.

[0090] The reagents and raw materials used in the present application are commercially available.

[0091] The positive progress effect of the present application is to provide a method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride, which is efficient, convenient and suitable for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0092] Figure 1 1H NMR (CDCl3) of 1,2-diiodo-4,5-dimethylbenzene;

[0093] Figure 2 H NMR (CDC13, 400 MHz) of 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl is:

[0094] Figure 3 H NMR (CDC13, 400 MHz) of 4,4',5,5'-tetramethyl-2,2'-di(trifluoromethyl)- biphenyl is:

[0095] Figure 4 F NMR (CDC13, 376 MHz) of 4,4',5,5'-tetramethyl-2,2'-di(trifluoromethyl)- biphenyl is:

[0096] Figure 5 H NMR (DMSO-d6, 400 MHz) of 2,2'-di(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid is:

[0097] Figure 6 F NMR (DMSO-d6, 376 MHz) of 2,2'-di(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid is: DETAILED DESCRIPTION

[0098] The present application is further illustrated by the following examples, which are not intended to limit the application in any way. The experimental procedures in the following examples, where no specific conditions are indicated, were carried out according to standard methods and conditions, or according to the instructions of the commercial suppliers.

[0099] Example 1

[0100] 1. Under nitrogen protection, 300 mL of glacial acetic acid, 60 mL of deionized water, and 9 mL of concentrated sulfuric acid (98%) were added into a 1000 mL three-necked flask, and stirred. Then o-xylene (500 mmol, 53.08 g), I2(450 mmol, 114.21 g), and periodic acid (200 mmol, 45.6 g) were added, and slowly heated to 70°C, and reacted for 24 hours. The reaction was stopped, and cooled to room temperature, and the reaction solution was poured into 2 L of 3% aqueous sodium sulfite solution, and stirred until the system was colorless. The water layer was removed, and the oily substance on the bottom and wall was dissolved with dichloromethane, dried with anhydrous sodium sulfate, filtered, concentrated, and 20 mL of ethanol was added, and a large amount of white solid was precipitated, filtered, and dried to obtain the product 1,2-diiodo-4,5-dimethylbenzene 161.1 g, with a yield of 90%. 1 H NMR (CDC13, 400 MHz): δ 7.62 (s, 2H), 2.15 (s, 6H) Figure 1

[0101] ​(80 mmol, 28.64 g) was dissolved in 400 mL of dry tetrahydrofuran (THF) under nitrogen protection, and then the temperature of the system was lowered to -78 °C with dry ice acetone bath, and then 40 mL of n-butyllithium (n-BuLi, 1 mol / L n-hexane solution, 40 mmol) solution was slowly added dropwise, and after the dropwise addition was completed, the reaction was continued at -78 °C for half an hour, and then the dry ice acetone bath was removed and slowly returned to room temperature. The reaction solution was poured into 1 L of deionized water, and then extracted with ethyl acetate (extracted three times), and the organic phase was combined, dried with anhydrous sodium sulfate, and then filtered and concentrated to obtain a solid (crude product), 20 ml of cooled ethanol was added to the crude product, and then stirred, filtered and washed, and dried to obtain the pure product 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl 15.71 g, yield 85%. 1 H NMR (CDCI3, 400 MHz): δ 7.68 (s, 2H), 6.93 (s, 2H), 2.27 (s, 6H), 2.23 (s, 6H) 3, 400MHz): δ 7.68 (s, 2H), 6.93 (s, 2H), 2.27 (s, 6H), 2.23 (s, 6H) Figure 2 );

[0102] (343.75 mmol, 19.9375 g, 5.5 equiv.) was added to a 1000 mL three-necked reaction flask, and then stirred at room temperature, and then TMSCF3 (343.75 mmol, 48.8125 g, 5.5 equiv.) was slowly added dropwise, and after the dropwise addition was completed, the reaction was continued at room temperature for 22 hours. Then 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl (62.5 mmol, 28.8750 g, 1.0 equiv.) obtained in ② was added, and the temperature was raised to 115 °C and the reaction was continued for 14 hours. Nuclear magnetic resonance tracking showed that the reaction was complete. The reaction was stopped, the reaction solution was filtered, and the insoluble was washed with a small amount of ethyl acetate, and then the filtrate was rotary evaporated to obtain a solid, which was washed with a large amount of PE / EA (volume ratio 10:1) mixed solvent, and the washing liquid was washed with saturated brine, dried with anhydrous sodium sulfate, filtered, concentrated and dried to obtain the colorless product 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl 21.22 g, yield 98%, mp 114-116 °C, 1 H NMR (CDCI3, 400 MHz): δ 7.68 (s, 2H), 6.93 (s, 2H), 2.27 (s, 6H), 2.23 (s, 6H) 3, 400MHz): δ 7.68 (s, 2H), 6.93 (s, 2H), 2.27 (s, 6H), 2.23 (s, 6H) Figure 3 ); 19 F NMR (CDCI3, 376 MHz): δ -57.73 (s) ( Figure 4 );The same procedure was followed to perform the experiment according to the conditions in the following table, and the yields of product P2 and monosubstituted product P1 were as follows.

[0103]

[0104] IV. Under nitrogen protection, 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl (15 mmol, 5.195 g) obtained in III, 180 mL of pyridine and 30 mL of deionized water were added into a 500 mL three-necked flask, heated to 90°C, and then 21.33 g (135 mmol) of KMnO4 was added in portions, and the reaction was continued at 90°C overnight. Hot filtration was performed, and the insoluble solid was washed with hot water for several times. The filtrate was combined and rotary evaporated to obtain a solid. 150 mL of deionized water and 6 g of NaOH were added to the solid to form a solution. The solution was transferred into a 500 mL three-necked flask, heated to 90°C, and 10.20 g of KMnO4 (64.5 mmol) was added in portions. The reaction was continued, and the reaction was tracked by fluorine nuclear magnetic resonance spectroscopy until the oxidation was complete. Then ethanol was added to quench the reaction, and the excess KMnO4 was consumed. Hot filtration was performed, and the filter cake was washed with hot water for several times. The filtrate was combined and concentrated to about 200 mL. The solution was acidified to pH 2.0 with concentrated hydrochloric acid, and then the solution was placed in the refrigerator to cool overnight to precipitate the product. Filtration and drying yielded 6.294 g of product 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid, with a yield of 90%. 1 H NMR (DMSO , 400 MHz): δ 8.28 (s, 2H), 7.85 (s, 2H) Figure 5 ); 19 F NMR (DMSO , 376 MHz): δ -57.42 (s) Figure 6 );

[0105] V. Under nitrogen protection, 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid (4.662 g, 10 mmol) obtained in IV was added into 30 mL of acetic anhydride and heated to reflux for 6 h, and then rapid filtration was performed, and the solid was washed with a small amount of cooled diethyl ether. The solid was collected and dried in a vacuum oven at 50°C for 10 h to obtain 3.92 g of product 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride, with a yield of 91%. 1H NMR (acetone-d6, 400 MHz) δ 8.67 (s, 2H), 8.29 (s, 2H); 19 F NMR (acetone-d6 , 376 MHz): δ -57.35 (s);

[0106] Example 2

[0107] ① Under nitrogen protection, 300 mL of glacial acetic acid, 60 mL of deionized water, and 9 mL of concentrated sulfuric acid (98%) were added into a 1000 mL three-necked reaction flask, stirred, and then o-xylene (500 mmol, 53.08 g), I2(450 mmol, 114.21 g), and periodic acid (200 mmol, 45.6 g) were added, slowly heated to 70°C, and reacted for 24 hours. The reaction was stopped, cooled to room temperature, and the reaction solution was poured into 2 L of 3% aqueous sodium sulfite solution, stirred until the system was colorless. The water layer was removed, and the oily substance on the bottom and wall was dissolved with dichloromethane, dried with anhydrous sodium sulfate, filtered, concentrated, 20 mL of ethanol was added, a large amount of white solid was precipitated, filtered, and dried to obtain the product 161.1 g with a yield of 90%.

[0108] ② Under nitrogen protection, 1,2-diiodo-4,5-dimethylbenzene (80 mmol, 28.64 g) obtained in ① was dissolved in 400 mL of dry tetrahydrofuran (THF), and then the system was cooled to -78°C with a dry ice acetone bath, and then 40 mL of n-butyllithium (n-BuLi, 1 mol / L in n-hexane, 20 mmol) solution was slowly added dropwise, and after the dropwise addition was completed, the reaction was continued at -78°C for half an hour, and then the dry ice acetone bath was removed and slowly returned to room temperature. The reaction solution was poured into 1 L of deionized water, and then extracted with ethyl acetate (extracted three times), and the organic phase was combined, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain a solid (crude product), which was then dissolved in a small amount of cooled ethanol, stirred, filtered, washed, and dried to obtain the pure product 15.71 g with a yield of 85%.

[0109] ③ Under nitrogen protection, add dry KF (343.75 mmol, 19.9375 g, 5.5 equiv.), activated CuCl (312.5 mmol, 30.9375 g, 5.0 equiv.), and dry DMF (500 mL) to a 1000 mL three-necked reaction flask. Stir at room temperature, then slowly add TMSCF3 (343.75 mmol, 48.8125 g, 5.5 equiv.). After the addition is complete, react at room temperature for 22 hours. Then, 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl (62.5 mmol, 28.8750 g, 1.0 equiv.) obtained in step ② was added, and the temperature was raised to 115 °C to continue the reaction for 14 hours. NMR spectroscopy confirmed that the reaction was complete. The reaction was stopped, and the reaction solution was filtered to remove insoluble matter. The insoluble matter was washed with a small amount of ethyl acetate, and the filtrate was then evaporated to dryness to obtain a solid. This solid was then soaked and washed with a large amount of PE / EA (volume ratio 10:1) mixed solvent. The washes were washed with saturated brine, dried with anhydrous sodium sulfate, filtered, concentrated, and dried to obtain 21.22 g of a colorless product, with a yield of 98%.

[0110] ④ Add 3,6-bis(trifluoromethyl)-meshtemonene (15 mmol, 5.195 g) obtained in ③ and 60 mL of 25% nitric acid to a 500 mL high-pressure reactor. Heat to 170 °C and react for 17 h. After cooling to room temperature, a solid precipitates. Soak and wash the solid with a small amount of cold water, filter, and dry to obtain 6.154 g of the product 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetraic acid, with a yield of 88%.

[0111] ⑤ Under nitrogen protection, the 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetraic acid (4.662 g, 10 mmol) obtained in ④ was added to 30 mL of acetic anhydride and heated under reflux for 6 h. The mixture was quickly filtered and washed with a small amount of cooled diethyl ether. The solid was collected and dried in a vacuum oven at 50 °C for 10 h to give 3.92 g of the product 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride, with a yield of 91%.

Claims

1. A method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride, characterized in that, It includes the following steps: ① In the presence of acid and solvent, o-xylene is subjected to an iodination reaction with an iodizing agent to obtain the 1,2-diiodo-4,5-xylene; ； ② In a solvent, 1,2-diiodo-4,5-xylene undergoes a coupling reaction in the presence of a base to give 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl; ； ③A: A mixed solution 1 is obtained by mixing a polar solvent, CuX, MF and TMSCF3; B: Add 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl to the above mixed solution 1 to react and obtain 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl; ； In step A, CuX is CuCl; MF is KF; the polar solvent is DMF; the reaction temperature is 20~30℃; the molar ratio of TMSCF3 to CuX is 1:0.9; the molar ratio of TMSCF3 to MF is 1:

1. In step B, the reaction temperature is 115°C; The molar ratio of TMSCF3 to 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl is 1:0.18; Step A further includes the following specific steps: under nitrogen protection, dry MF is added to the dry polar solvent, and after the activated CuX is added, TMSCF3 is slowly added dropwise to obtain mixed solution 1; ④ In the presence of a solvent, 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl reacts with an oxidizing agent to yield 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetraic acid; ； ⑤ 2,2'-Di(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid was dehydrated and cyclized to give 2,2'-di(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride; 。 2. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 1, characterized in that, Step ① satisfies one or more of the following conditions: (1) The acid is an inorganic acid; (2) The iodizing agent is iodine and / or periodic acid; (3) The solvent is a water-soluble organic solvent and water; (4) The molar ratio of o-xylene to the acid is 1:0.1 to 1:0.4; (5) The reaction temperature of the iodination reaction is 0~100℃; (6) In the iodination reaction, the reactants consist of the following substances: the acid, the iodination reagent, the o-xylene and the solvent.

3. The preparation method according to claim 2, characterized in that, Step ① satisfies one or more of the following conditions: (1) The acid is concentrated sulfuric acid; (2) The iodizing reagent is iodine and periodic acid; (3) The solvent is acetic acid and water; (4) The molar ratio of o-xylene to the acid is 1:0.15 to 1:0.45; (5) The molar ratio of o-xylene to iodine is 1:0.8 to 1:1.2; (6) The molar ratio of o-xylene to periodic acid is 1:0.2 to 1:0.6; (7) The reaction temperature of the iodination reaction is 50~80℃; (8) The iodination reaction further includes the following steps: under nitrogen protection, o-xylene and the iodination reagent are added to the mixture of the acid and the solvent, and the temperature is slowly raised to the reaction temperature to obtain 1,2-diiodo-4,5-dimethylbenzene.

4. The preparation method according to claim 2, characterized in that, Step ① satisfies one or more of the following conditions: (1) The solvent is acetic acid and water, and the volume ratio of acetic acid to water is 5:1; (2) The molar ratio of o-xylene to the acid is 1:0.33; (3) The molar ratio of o-xylene to iodine is 1:0.9; (4) The molar ratio of o-xylene to periodic acid is 1:0.4; (5) The reaction temperature of the iodination reaction is 70℃.

5. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 1, characterized in that, Step ② above satisfies one or more of the following conditions: (1) The base is an alkyl lithium reagent; (2) The solvent is a cyclic ether solvent; (3) The reaction temperature of the coupling reaction is -100~-30℃; (4) The molar ratio of the 1,2-diiodo-4,5-xylene to the base is 1:0.4 to 1:0.6; (5) In the coupling reaction, the reactants consist of the following substances: the solvent, the 1,2-diiodo-4,5-xylene and the base.

6. The preparation method according to claim 5, characterized in that, Step ② above satisfies one or more of the following conditions: (1) The base is n-butyllithium; (2) The solvent is tetrahydrofuran; (3) The reaction temperature is -80~-50℃; (4) The molar ratio of the 1,2-diiodo-4,5-xylene to the base is 1:0.45 to 1:0.55; (5) The coupling reaction further includes the following steps: under nitrogen protection, the 1,2-diiodo-4,5-xylene and the solvent are mixed, the temperature is lowered to the reaction temperature of the coupling reaction, the base is slowly added dropwise, and the reaction yields the 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl.

7. The preparation method according to claim 5, characterized in that, Step ② above satisfies one or more of the following conditions: (1) The alkali is a n-butyllithium n-hexane solution; (2) The reaction temperature is -78℃; (3) The molar ratio of 1,2-diiodo-4,5-xylene to the base is 1:0.

5.

8. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 1, characterized in that, Step ③ above satisfies one or more of the following conditions: (1) In step A, the CuX undergoes an activation treatment, which includes the following steps: dissolving CuX in acid, diluting with water to precipitate the precipitate, filtering, washing, drying, protecting from light, and storing under a protective gas for later use. (2) In step A, the reactants consist of the following substances: the polar solvent, CuX, MF and TMSCF3; (3) In step B, the reactants consist of the following substances: the mixed solution and the 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl.

9. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 1, characterized in that, Step ④ above must satisfy one or more of the following conditions; (1) The oxidation reaction further includes the following steps: under nitrogen protection, the 2,2'-bis(trifluoromethyl)-4,4', 5, 5'-tetramethylbiphenyl and the solvent are added, heated, the oxidant is added, and the reaction is carried out at a constant temperature to obtain 2,2'-bis(trifluoromethyl)-4,4', 5, 5'-biphenyltetracarboxylic acid; (2) In the oxidation reaction, the solvent is a water-soluble polar solvent and / or water; (3) In the oxidation reaction, the oxidant is potassium permanganate, sodium dichromate, potassium dichromate or nitric acid; (5) The molar ratio of the 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl to the oxidant is 1:10 to 1:20; (6) The reaction temperature is 80~200℃.

10. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 1, characterized in that, In step ④ above, When the oxidant is potassium permanganate, sodium dichromate or potassium dichromate, the reaction further includes a base, wherein the base is sodium hydroxide and / or pyridine.

11. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 10, characterized in that, The alkali is sodium hydroxide.

12. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 10, characterized in that, In step ④ above, the molar ratio of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl to the base is 1:5 to 1:

15.

13. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 10, characterized in that, In step ④ above, the molar ratio of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl to the base is 1:8 to 1:

12.

14. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 10, characterized in that, In step ④ above, the molar ratio of 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl to the base is 1:8.

3.

15. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 10, characterized in that, The oxidation reaction includes the following steps: under nitrogen protection, 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl and the solvent are added, heated, the oxidant is added, the reaction is carried out at a constant temperature, filtered while hot, the filtered insoluble solid is washed with hot water, the filtrates are combined and evaporated to dryness to obtain a solid; the solvent and the base are added to the solid to form a solution, heated, the oxidant is added in batches to continue the reaction, and 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetraic acid is obtained.

16. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 1, characterized in that, In the oxidation reaction, the reactants consist of the following substances: the 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, the solvent, and the oxidant.

17. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 10, characterized in that, In the oxidation reaction, the reactants consist of the following substances: the 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, the solvent, the base, and the oxidant.

18. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 1, characterized in that, Step ④ above must satisfy one or more of the following conditions; (1) In the oxidation reaction, the solvent is deionized water; (2) In the oxidation reaction, the oxidant is potassium permanganate or 25% nitric acid; (3) The molar ratio of the 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl to the oxidant is 1:13 to 1:18; (4) The reaction temperature is 90~170℃.

19. The method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyl dianhydride as described in claim 1, characterized in that, Step ④ above must satisfy one or more of the following conditions; (2) The molar ratio of the 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl to the oxidant is 1:13 or 1:18; (3) The reaction temperature is 90℃ or 170℃.

20. A method for preparing 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl, characterized in that, It includes the following steps: A: A mixed solution 1 is obtained by mixing polar solvent, CuX, MF and TMSCF3; B: Add 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl to the above mixed solution 1 to react and obtain 2,2'-bis(trifluoromethyl)-4,4',5,5'-tetramethylbiphenyl; In step A, CuX is CuCl; MF is KF; the polar solvent is DMF; the reaction temperature is 20~30℃; the molar ratio of TMSCF3 to CuX is 1:0.9; the molar ratio of TMSCF3 to MF is 1:

1. In step B, the reaction temperature is 115°C; The molar ratio of TMSCF3 to 2,2'-diiodo-4,4',5,5'-tetramethylbiphenyl is 1:0.18; Step A further includes the following specific steps: under nitrogen protection, dry MF is added to the dry polar solvent, and after the activated CuX is added, TMSCF3 is slowly added dropwise to obtain mixed solution 1.

21. The preparation method according to claim 20, characterized in that, Its operation and conditions are as described in claim 1 or 8.

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