Process for the preparation of a perfluoroether rubber crosslinking aid

Abstract

This invention discloses a method for preparing a perfluoroether rubber crosslinking aid. The invention provides a method for preparing a compound as shown in Formula I, comprising the following steps: in an organic solvent, in the presence of a metal reagent, a compound as shown in Formula II undergoes an addition-elimination reaction with tetrafluoroethylene to generate the compound as shown in Formula I. The preparation method provided by this invention has short synthetic steps, uses inexpensive and readily available reagents, and has a high product yield, showing potential for large-scale engineering preparation.

Description

Technical Field

[0001] This invention relates to a method for preparing a crosslinking aid for perfluoroether rubber. Background Technology

[0002] High-temperature steam is widely used in various industrial processes, such as semiconductor manufacturing equipment and chemical plants. Seals are required during steam transport to prevent steam leakage from piping systems or equipment. In these cases, perfluoroelastomer (FFKM) is used due to its excellent chemical and thermal stability. With the development of modern industry, especially in the semiconductor industry where the pressure of exposed gases changes drastically, higher demands are placed on the sealing of high-temperature steam. Sealing materials need to have very low swelling ratios to prevent cracking and maintain the high purity of semiconductor materials. Cross-linked perfluoroelastomers are needed as suitable sealing materials that are resistant to high temperatures, steam, and chemicals. However, cross-linked materials formed by general cross-linking agents such as triallyl urate (TAIC) [Reference WPT2010 / 099057] have a service temperature limit of no more than 300°C, indicating insufficient resistance to high-temperature steam. This means their performance needs further improvement. Further development of cross-linking agents that can form cross-linked structures with higher heat resistance is needed to meet the high-temperature steam sealing requirements of different industries.

[0003] Among crosslinking agents for phenyl-containing perfluoroelastomers, the crosslinking agent 1,1'-(1,1,2,2,3,3,4,4,5,6,6-dodecano-1,6-hexadiyl)bis[4-(1,2,2-trifluorovinyl)benzene (CAS: 1653294-96-2) exhibits the best performance in high-temperature steam sealing, with the lowest weight expansion ratio and the lowest expansion change rate, demonstrating excellent high-temperature steam resistance (Tomoya Shimizu. Sealing Technology. 2017, 7-11). Currently, its synthesis method is not reported in the literature, only described in patent (WO2015019581): 1,6-diiodoperfluorohexane is used as a substrate and coupled with p-iodoaniline via bilateral Ullmann coupling, followed by a Sandmeyer reaction using a diazonium salt to convert it to aryliodoiodine, and then palladium-catalyzed coupling to form the final product. The synthesis process is complex, difficult to control, costly, and difficult to engineer. When the applicant replicates the patented reaction, the yield is only about 10%. Summary of the Invention

[0004] The technical problem solved by this invention is to address the shortcomings of existing methods for synthesizing perfluoroether crosslinking agents, which suffer from complex reactions and low yields, and to provide a more effective preparation method. This invention provides a method for preparing a perfluoroether rubber crosslinking aid. The preparation method provided by this invention has short synthesis steps, uses inexpensive and readily available reagents, and has a high product yield, showing great potential for large-scale engineering preparation.

[0005] The present invention solves the above-mentioned technical problems through the following solutions.

[0006] This invention provides a method for preparing a compound as shown in Formula I, comprising the following steps:

[0007] In an organic solvent, in the presence of a metallic reagent, the compound shown in Formula II undergoes an addition-elimination reaction with tetrafluoroethylene to generate the compound shown in Formula I.

[0008]

[0009] In some embodiments of the present invention, the organic solvent is a hydrocarbon solvent and / or an ether solvent, preferably one or more of n-hexane, cyclohexane, n-heptane, methylcyclohexane, 2-methylpentane, isooctane, 1,2-dimethoxyethane, diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 2-methoxyethyl ether, and diethylene glycol dimethyl ether, more preferably diethyl ether, tetrahydrofuran, or 2-methyltetrahydrofuran.

[0010] In some embodiments of the present invention, the metal reagent may be an activated metal, a Grignard reagent, or an organolithium reagent;

[0011] Better place,

[0012] The activated metal may be activated magnesium powder or activated zinc powder, preferably activated magnesium powder;

[0013] The organolithium reagent may be methyllithium (MeLi), n-butyllithium (n-BuLi) or sec-butyllithium, preferably methyllithium or n-butyllithium;

[0014] The Grignard reagent may be ethyl magnesium bromide, methyl magnesium bromide (MeMgBr), ethyl magnesium bromide (EtMgBr), butyl magnesium chloride, or phenyl magnesium chloride, preferably methyl magnesium bromide or ethyl magnesium bromide.

[0015] In some embodiments of the present invention, the molar ratio of the metal reagent to the compound shown in Formula II is (2-4):1, preferably 2.2:1, 2.4:1, 2.5:1 or 4:1.

[0016] In some embodiments of the present invention, the molar ratio of the tetrafluoroethylene to the compound shown in Formula II is (5-20):1, preferably 5:1, 7.5:1 or 10:1.

[0017] In some embodiments of the present invention, the molar volume ratio of the compound as shown in Formula II to the organic solvent is 0.1 to 0.5 mmol / mL, preferably 0.2 mmol / mL or 0.25 mmol / mL.

[0018] In some embodiments of the present invention, the concentration of the organolithium reagent may be 1.2M to 2M, preferably 1.6M; the concentration refers to the concentration of the organolithium reagent when it is added to the reaction.

[0019] In some embodiments of the present invention, the concentration of the Grignard reagent may be 1M to 5M, preferably 1M or 3M; the concentration refers to the concentration of the Grignard reagent when it is added to the reaction.

[0020] In some embodiments of the present invention, the reaction is carried out under an inert gas protection, such as nitrogen protection.

[0021] In some embodiments of the present invention, the preparation method includes the following steps:

[0022] Step 1: Mix the compound shown in Formula II with the organic solvent, then add the metal reagent to react and obtain an aryl metal reagent;

[0023] Step 2: The aryl metal reagent is added to the organic solvent containing tetrafluoroethylene to react and generate a compound as shown in Formula I.

[0024] In some embodiments of the present invention, in step one, the feeding temperature of the metal reagent can be -78°C to 25°C; preferably,

[0025] When the metal reagent is an organolithium reagent, the preferred feeding temperature of the metal reagent is -78℃ to -60℃, for example -70℃;

[0026] When the metal reagent is an activated metal or a Grignard reagent, the preferred feeding temperature of the metal reagent is 0℃~50℃.

[0027] In some embodiments of the present invention, in step one, the metal reagent is added by dripping.

[0028] In some embodiments of the present invention, in step one, the reaction temperature can be 0°C to 70°C; preferably,

[0029] When the metal reagent is an organolithium reagent, the reaction temperature is preferably -5℃ to 5℃, for example, 0℃;

[0030] When the metal reagent is a Grignard reagent, the reaction temperature is preferably 40℃~50℃;

[0031] When the metal reagent is an activated metal, the reaction temperature is preferably 60°C to 80°C, for example, 70°C.

[0032] In some embodiments of the present invention, the reaction time in step one can be 1h to 3h, for example 2h.

[0033] In some embodiments of the present invention, in step one, the reaction can be carried out using a magnetic stirrer, preferably at a speed of 400 to 1200 revolutions per minute.

[0034] In some embodiments of the present invention, step one is carried out under anhydrous and inert gas protection, such as nitrogen.

[0035] In some embodiments of the present invention, in step two, the feeding temperature of the reaction can be -78°C to 0°C; preferably -40°C.

[0036] In some embodiments of the present invention, in step two, the aryl metal reagent is added dropwise.

[0037] In some embodiments of the present invention, in step two, the reaction temperature can be -78℃ to 0℃, preferably -40℃ to 0℃.

[0038] In some embodiments of the present invention, in step two, the reaction can be carried out in a reaction vessel, preferably a reaction vessel equipped with mechanical stirring and high and low temperature circulation.

[0039] In some embodiments of the present invention, in step two, when the aryl metal reagent is added, the pressure of the reaction system is 1 atm to 2 atm.

[0040] In some embodiments of the present invention, in step two, the reaction process is detected using conventional monitoring methods for such reactions in the art, such as TLC, HPLC, etc. Preferably, the reaction endpoint is defined as the complete conversion of tetrafluoroethylene or the cessation of the formation of the compound shown in Formula I, and the reaction time is preferably 1–4 hours.

[0041] In some embodiments of the present invention, the preparation method further includes the following post-processing step: reaction After completion, add After water quenching, the temperature is slowly raised to room temperature, followed by post-processing using conventional methods in the field. The process involves, for example, concentrating and purifying the organic phase to obtain a compound as shown in Formula I; wherein the purification is preferably silica gel column purification, and the eluent for the silica gel column is preferably petroleum ether.

[0042] In some embodiments of the present invention, the preparation method preferably uses a low-temperature cycle of ethanol medium to control the reaction temperature.

[0043] In some embodiments of the present invention, the preparation method further includes a method for preparing the compound shown in Formula II, which includes the following steps: in an organic solvent, in the presence of metallic copper or a copper salt, the compound shown in Formula III undergoes a selective coupling reaction with p-chloroiodobenzene to generate the compound shown in Formula II.

[0044]

[0045] In some embodiments of the present invention, the metallic copper in the selective coupling reaction is copper powder (Cu).

[0046] In some embodiments of the present invention, in the selective coupling reaction, the copper salt is a monovalent copper salt, such as cuprous iodide (CuI), cuprous bromide (CuBr), or cuprous chloride (CuCl), preferably cuprous iodide.

[0047] In some embodiments of the present invention, the selective coupling reaction further includes a base and a ligand; wherein the base may be an inorganic base; and the ligand may be a monodentate ligand or a bidentate ligand.

[0048] Better place,

[0049] The inorganic base is sodium carbonate (Na2CO3), potassium carbonate (K2CO3), cesium carbonate (Cs2CO3), potassium hydroxide (KOH), potassium fluoride (KF), or potassium phosphate (K3PO4), preferably potassium carbonate (K2CO3), cesium carbonate (Cs2CO3), or potassium fluoride (KF);

[0050] The monodentate ligand is N-methylglycine, proline, or N,N-dimethylglycine, preferably proline;

[0051] The bidentate ligand is 2,2-bipyridine, phenanthroline, or N,N'-dimethyl-1,2-ethylenediamine, preferably 2,2-bipyridine.

[0052] In some embodiments of the present invention, in the selective coupling reaction, the organic solvent may be selected from one or more of nitrile solvents, amide solvents, sulfoxide solvents and ether solvents, such as one or more of acetonitrile (MeCN), N-methylpyrrolidone (NMP), N,N'-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF) and 1,4-dioxane, preferably acetonitrile, DMF or DMSO.

[0053] In some embodiments of the present invention, in the selective coupling reaction, the molar ratio of the metallic copper or copper salt to the compound shown in Formula III is 1:(1 to 20), preferably 1:20.

[0054] In some embodiments of the present invention, in the selective coupling reaction, the molar ratio of p-chloroiodobenzene to the compound shown in Formula III is (2-5):1, preferably 2:1.

[0055] In some embodiments of the present invention, in the selective coupling reaction, the molar volume ratio of the compound as shown in Formula III to the organic solvent is 0.1 to 1 mmol / mL, preferably 0.2 mmol / mL.

[0056] In some embodiments of the present invention, in the selective coupling reaction, the molar ratio of the base to the compound as shown in Formula III is (0-5):1, preferably 2:1.

[0057] In some embodiments of the present invention, in the selective coupling reaction, the molar ratio of the ligand to the compound as shown in Formula III is (0-1):1, preferably 0.8:1 or 0.4:1.

[0058] In some embodiments of the present invention, the selective coupling reaction is carried out under the protection of an inert gas, such as nitrogen.

[0059] In some embodiments of the present invention, the temperature of the selective coupling reaction is 30°C to 160°C, preferably 80°C to 100°C.

[0060] In some embodiments of the present invention, the selective coupling reaction is carried out under mechanical stirring, preferably at a stirring speed of 50 to 600 revolutions per minute.

[0061] In some embodiments of the present invention, the selective coupling reaction further includes the following post-processing steps: after the reaction is completed, it is processed by conventional post-processing methods in the art (e.g., after quenching the reaction with water, extraction and separation are performed using solvents such as EA, followed by concentration column purification, etc.).

[0062] In some embodiments of the present invention, the reaction process of the selective coupling reaction can be tested using methods commonly used in the art (e.g., 19 The reaction is monitored by 1F-NMR, and the endpoint is generally defined as the disappearance of the compound shown in Formula III or the cessation of the formation of the compound shown in Formula II.

[0063] The present invention also provides a method for preparing the compound shown in Formula II, which includes the following steps: in an organic solvent, in the presence of metallic copper or copper salt, the compound shown in Formula III undergoes a selective coupling reaction with p-chloroiodobenzene to generate the compound shown in Formula II.

[0064]

[0065] Preferably, the preparation method of the compound shown in Formula II is as described in any of the foregoing embodiments of the present invention.

[0066] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0067] The reagents and raw materials used in this invention are all commercially available.

[0068] The positive and progressive effects of this invention are as follows:

[0069] This invention utilizes commercially available raw material (I(CF2)6I) and common, inexpensive, and readily available reagents to obtain the key intermediate (II) via a selective Ullmann condensation reaction. Further, an aryl metal reagent is prepared, followed by an addition-elimination reaction with inexpensive tetrafluoroethylene to yield a valuable fluororubber crosslinking agent. Compared to existing synthetic methods, this method has fewer steps, uses inexpensive and readily available reagents, and achieves higher yields, demonstrating significant potential for large-scale engineering production. It provides a solid foundation for the development of high-temperature, water vapor-resistant perfluoroether rubber sealing materials. Detailed Implementation

[0070] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0071] The structure and purity of the compound were determined by nuclear magnetic resonance (NMR). 19 The determination was performed using nuclear magnetic resonance (NMR) technology, employing a Bruker AVANCE 300 instrument, with the solvent being the solvent used in the reaction.

[0072] The main steps of this invention are divided into two steps:

[0073]

[0074] Step 1: The key intermediate compound (II) is prepared by Ullmann coupling of compound (III) with perfluoroalkyl diiodide compound (I(CF2)6I) via copper catalysis or copper-mediated coupling.

[0075] Step 2: Preparation of compound (II) with metal reagent. The aryl metal reagent undergoes an addition-elimination reaction with tetrafluoroethylene (TFE) in a specific solvent to obtain the target product compound (I).

[0076] Example of Step 1:

[0077] Example 1

[0078]

[0079] In a 1L round-bottom three-necked flask equipped with a magnetic stir bar and a cooling reflux tube, weigh the substrate p-chloroiodobenzene (47.6 g, 200 mmol), copper powder (12.8 g, 200 mmol), and the raw material 1,6-diiodoperfluorohexane (55.4 g, 100 mmol) shown in formula (III) and add them to the reaction flask. Seal with a rubber stopper, replace the nitrogen gas with a double-row oil pump, and add the ultra-dry solvent dimethyl sulfoxide (DMSO) (500 mL) through a syringe. React for 6 h under oil bath at 100°C with magnetic stirring at 500 rpm. After the fluorine spectrum detection showed the reaction was complete, the temperature was lowered to room temperature. Water was added to quench the reaction, and then EA (500 mL * 4) was added for extraction. The organic phase was washed three times with water and saturated saline solution at a volume ratio of (1:1) (1 L * 3). After drying with saturated saline solution, the organic phase was dried with anhydrous sodium sulfate and concentrated by rotary evaporation to obtain the crude product. After column purification and elution (PE:DCM = 100:1), a total of 46.1 g of white crystalline target product was obtained (yield 88.1%).

[0080] Example 2

[0081]

[0082] In a 1L round-bottom three-necked flask equipped with a magnetic stir bar and a cooling reflux tube, weigh the following substrates: p-chloroiodobenzene (47.6 g, 200 mmol), CuI (3.8 g, 20 mmol), KF (11.6 g, 200 mmol), and proline L2 (4.6 g, 40 mmol). Weigh the following raw material: 1,6-diiodoperfluorohexane (55.4 g, 100 mmol) as shown in formula (III). Add the mixture to the reaction flask, seal it with a rubber stopper, replace the nitrogen gas with a double-row oil pump, and then add the ultra-dry solvent N,N'-dimethylformamide (DMF) (400 mL) through a syringe. React for 12 h under oil bath conditions at 110°C with magnetic stirring at 600 rpm. After the fluorine spectrum detection showed the reaction was complete, the temperature was lowered to room temperature. Water was added to quench the reaction, and then EA (400 mL * 3) was added for extraction. The organic phase was washed four times with water and saturated saline solution at a volume ratio of (1:1) (500 mL * 4). The phase was dried with saturated saline solution, separated, and the organic phase was dried with anhydrous sodium sulfate and concentrated by rotary evaporation to obtain the crude product. The crude product was purified by column purification (PE:DCM = 100:1) to obtain a total of 48.1 g of white crystalline target product (yield 92.3%).

[0083] Example 3

[0084]

[0085] In a 500 mL round-bottom three-necked flask equipped with a magnetic stir bar and a cooling reflux tube, weigh the following substrates: p-chloroiodobenzene (11.9 g, 50 mmol), CuBr (1.43 g, 10 mmol), Cs2CO3 (9.65 g, 50 mmol), and proline L2 (1.15 g, 10 mmol). Weigh the following starting material: 1,6-diiodoperfluorohexane (13.1 g, 25 mmol) as shown in formula (III) and add them to the reaction flask. Seal the flask with a rubber stopper. After replacing the nitrogen gas with a double-row oil pump, add 200 mL of ultra-dry solvent N,N'-dimethylformamide (DMF) through a syringe. React for 8 h under oil bath at 90 °C with magnetic stirring at 700 rpm. After the fluorine spectrum detection showed the reaction was complete, the temperature was lowered to room temperature. Water was added to quench the reaction, and then EA (100 mL * 3) was added for extraction. The organic phase was washed four times with water and saturated saline solution at a volume ratio of (1:1) (200 mL * 4). The phase was dried with saturated saline solution, separated, and the organic phase was dried with anhydrous sodium sulfate and concentrated by rotary evaporation to obtain the crude product. The crude product was purified by column purification (PE:DCM = 100:1) to obtain a total of 11.6 g of white crystalline target product (yield 87.1%).

[0086] Example 4

[0087]

[0088] In a 1L round-bottom three-necked flask equipped with a magnetic stir bar and a cooling reflux tube, weigh the following substrates: p-chloroiodobenzene (23.8 g, 100 mmol), CuCl (2.0 g, 20 mmol), K2CO3 (13.8 g, 100 mmol), and 2,2-bipyridine L4 (6.24 g, 40 mmol). Weigh the following raw material: 1,6-diiodoperfluorohexane (27.7 g, 50 mmol) as shown in formula (III) and add them to the reaction flask. Seal the flask with a rubber stopper. After replacing the nitrogen gas with a double-row tube and an oil pump, add the ultra-dry solvent N,N'-dimethylacetamide (DMAc) (500 mL) through a syringe. React for 10 h under oil bath at 110°C with magnetic stirring at 800 rpm. After the fluorine spectrum detection showed the reaction was complete, the mixture was cooled to room temperature. Water was added to quench the reaction, followed by extraction with EA (200 mL * 3). The organic phase was washed four times with a water and saturated brine volume ratio of (1:1) (300 mL * 4). The mixture was then dried with saturated brine. After separation, the organic phase was dried with anhydrous sodium sulfate and concentrated by rotary evaporation to obtain the crude product. The crude product was purified by column purification (PE:DCM = 100:1) to obtain a total of 21.3 g of white crystalline target product (yield 81.3%).

[0089] Example 5

[0090]

[0091] In a 1L round-bottom three-necked flask equipped with a magnetic stir bar and a cooling reflux tube, weigh the following substrates: p-chloroiodobenzene (23.8 g, 100 mmol), CuI (3.8 g, 20 mmol), K2CO3 (13.8 g, 100 mmol), and 2,2-bipyridine L4 (6.24 g, 40 mmol). Weigh the following raw material: 1,6-diiodoperfluorohexane (27.7 g, 50 mmol) as shown in formula (III) and add them to the reaction flask. Seal the flask with a rubber stopper. After replacing the nitrogen gas with a double-row tube and an oil pump, add the ultra-dry solvent dimethyl sulfoxide (DMSO) (500 mL) through a syringe. React for 10 h under oil bath conditions at 100°C with magnetic stirring at 600 rpm. After the fluorine spectrum detection showed the reaction was complete, the temperature was lowered to room temperature. Water was added to quench the reaction, and then EA (200 mL * 3) was added for extraction. The organic phase was washed four times with water and saturated saline solution at a volume ratio of (1:1) (300 mL * 4). The phase was dried with saturated saline solution, separated, and the organic phase was dried with anhydrous sodium sulfate and concentrated by rotary evaporation to obtain the crude product. The crude product was purified by column purification (PE:DCM = 100:1) to obtain a total of 25.5 g of white crystalline target product (yield 92.3%).

[0092] Step Two Example:

[0093] Example 6

[0094]

[0095] Weigh 52.3 g (100 mmol) of the raw material shown in formula (II) into a 1 L round-bottom three-necked flask containing a magnetic inlet and add it to the reaction flask. Seal the flask with a rubber stopper. After replacing the nitrogen gas with a double-row tube and an oil pump, add 500 mL of ultra-dry tetrahydrofuran (THF) using a syringe under nitrogen protection. Cool the resulting solvent to -70 °C using a dry ice ethanol bath. Then, slowly add 138 mL (220 mmol) of MeLi (1.6 M in Et2O) to the reaction flask dropwise over a period of 60 mins. After the addition is complete, keep the flask in an ice-water bath at 0 °C for 2 h before use.

[0096] In a 2L clean reactor equipped with mechanical stirring and high / low temperature circulation, 500 mL of tetrahydrofuran (THF) solvent was added. The reactor was cooled to -40°C using a cooling cycle. Tetrafluoroethylene (100 g, 1 mol) was slowly introduced through the gas phase valve for 2 hours. After maintaining the pressure (1-2 atm) for 1 hour, the prepared aryl lithium reagent was slowly added to the reaction system through the liquid phase port using a pressure pump for 2 hours. The reaction was then carried out at -40°C for 1 hour and maintained at 0°C for 3 hours. The temperature was then slowly raised to room temperature while depressurizing. The tail gas was introduced into a treatment device, quenched with water, and the organic phase was collected, concentrated, and purified by column chromatography using pure petroleum ether to obtain a 38.7 g white crystalline solid with a yield of 63.1% and a fluorocarbon backbone diaryltrifluoroolefin crosslinking agent.

[0097] Example 7

[0098]

[0099] Weigh 52.3 g (100 mmol) of the raw material shown in formula (II) into a 1 L round-bottom three-necked flask containing a magnetic stopper and add it to the reaction flask. Seal the flask with a rubber stopper. After replacing the nitrogen gas with a double-row tube and an oil pump, add 500 mL of redistilled diethyl ether (Et2O) containing NaH under nitrogen protection using a syringe. Cool the resulting solvent to -70 °C using a dry ice ethanol bath. Then, slowly add n-BuLi (1.6 M in Hexane) (138 mL, 220 mmol) dropwise to the reaction flask over a period of 60 mins. After the addition is complete, keep the flask in an ice-water bath at 0 °C for 2 h before use.

[0100] In a 2L clean reactor equipped with mechanical stirring and high / low temperature circulation, 500mL of redistilled diethyl ether (Et2O) containing NaH was added. The reactor was cooled to -40°C using a cooling cycle. Tetrafluoroethylene (50g, 500mol) was slowly introduced through a gas phase valve for 2 hours. After maintaining the pressure (1-2 atm) for 1 hour, the prepared aryl lithium reagent was slowly added to the reaction system through a pressure pump via a liquid phase port for 2 hours. The reaction was then carried out at -40°C for 1 hour and maintained at 0°C for 2 hours. The temperature was then slowly raised to room temperature while depressurizing. The tail gas was introduced into a treatment device, quenched with water, and the organic phase was collected, concentrated, and purified by column chromatography using pure petroleum ether to obtain a 40.3g white crystalline solid of the diaryltrifluoroene crosslinking agent with a fluorocarbon backbone as shown in formula (I), with a yield of 65.5%.

[0101] Example 8

[0102]

[0103] Weigh the raw material (104.6 g, 200 mmol) shown in Formula (II) into a 2L round-bottom three-necked flask equipped with a magnetic inlet and a reflux condenser. Seal the flask with a rubber stopper. After replacing the nitrogen gas with a double-row tube and an oil pump, add 600 mL of ultra-dry dimethyltetrahydrofuran (2-Me-THF) under nitrogen protection using a syringe. At room temperature, slowly add 500 mL (500 mmol) of MeMgBr (1 M inTHF) to the flask dropwise over 60 mins. After the addition is complete, reflux the resulting reaction solution at 50°C for 2 h, then turn off the heating and transfer the solution to a liquid chromatography autogenous system at room temperature for preparation.

[0104] 800 mL of ultra-dry dimethyltetrahydrofuran (2-MeTHF) was added to a 2 L clean reactor equipped with mechanical stirring and high / low temperature circulation. The reactor was cooled to -40 °C using a cooling cycle. Tetrafluoroethylene (150 g, 1.5 mol) was slowly introduced through the gas phase valve for 2 h. After maintaining the pressure at 1-2 atm for 1 h at the same temperature, the liquid phase pipeline switch was opened, and the prepared aryl Grignard reagent was slowly added to the reaction system by a pressure pump for 2 h. The reaction was then carried out at -40 °C for 1 h, maintained at 0 °C for 3 h, and then slowly raised to room temperature while depressurizing. The tail gas was introduced into a treatment device, quenched with water, and the organic phase of the reactor was collected, concentrated, and purified by silica gel column chromatography. The crosslinking agent of the fluorocarbon backbone shown in formula (I) was obtained by elution with pure petroleum ether. 51.9 g of white crystalline solid was obtained, with a yield of 84.6%.

[0105] Example 9

[0106]

[0107] Weigh 52.3 g (100 mmol) of the raw material shown in formula (II) into a 1 L round-bottom three-necked flask equipped with a magnetic inlet and a reflux condenser. Seal the flask with a rubber stopper. After replacing the nitrogen gas with a double-row tube and an oil pump, add 500 mL of redistilled sodium hydride (NaH) ether (Et2O) using a syringe under nitrogen protection. At room temperature, slowly add 80 mL (240 mmol) of EtMgBr (3 M in Et2O) dropwise to the reaction flask over 60 mins. After the addition is complete, reflux the resulting reaction solution at 40 °C for 2 h, then turn off the heating and transfer the solution to a liquid chromatography autogenous system at room temperature for preparation.

[0108] Add 500 mL of redistilled sodium hydride (NaH) ether (Et2O) to a 2 L clean reactor equipped with mechanical stirring and high / low temperature circulation. Cool the reactor to -40 °C using a cooling cycle. Slowly introduce tetrafluoroethylene (50 g, 500 mmol) through the gas phase valve for 2 h. Maintain pressure (1-2 atm) at the same temperature for 1 h. Open the liquid phase pipeline switch and slowly add the prepared aryl Grignard reagent to the reaction system using a pressure pump. Continue for 2 h. React at -40 °C for 1 h. Maintain 0 °C for 3 h. Slowly raise to room temperature while depressurizing. Pass the tail gas into a treatment device and quench it with water. Collect the organic phase from the reactor and concentrate it. Purify it by silica gel column chromatography. Elute with pure petroleum ether to obtain 51.5 g of a white crystalline solid with a fluorocarbon backbone as shown in formula (I), yielding 83.9%.

[0109] Example 10

[0110]

[0111] At room temperature, weigh the raw material (52.3 g, 100 mmol) and activated magnesium powder (96 g, 400 mmol) shown in formula (II) into a 1 L round-bottom three-necked flask equipped with a magnetic inlet and a reflux condenser. Seal the flask with a rubber stopper. After replacing the nitrogen gas with a double-row tube and an oil pump, add 500 mL of ultra-dry tetrahydrofuran (THF) under nitrogen protection using a syringe. Heat the resulting reaction solution to reflux at 70 °C for 2 h until the solid content no longer decreases. Then transfer the solution to a liquid phase injection vessel for preparation.

[0112] In a 2L clean reactor equipped with mechanical stirring and high / low temperature circulation, 500 mL of tetrahydrofuran (THF) solvent was added. The reactor was cooled to -40°C using a cooling cycle. Tetrafluoroethylene (100 g, 1 mol) was slowly introduced through the gas phase valve for 2 hours. After maintaining the pressure (1-2 atm) for 1 hour, the prepared aryl Grignard reagent was slowly added to the reaction system through the liquid phase port using a pressure pump for 2 hours. The reaction was then carried out at -40°C for 1 hour and maintained at 0°C for 3 hours. The temperature was then slowly raised to room temperature while depressurizing. The tail gas was introduced into a treatment device, quenched with water, and the organic phase was collected, concentrated, and purified by silica gel column chromatography. The crosslinking agent with a fluorocarbon backbone of formula (I) was obtained by elution with pure petroleum ether. 49.7 g of white crystalline solid was obtained, with a yield of 80.8% and a purity of 99.63% as determined by HPLC.

[0113] The NMR data of the crosslinking agent final product are as follows:

[0114] 19F NMR(376MHz,CDCl3)δppm-96.4(dd,J=33.4,63.3Hz,2F),-111.1(p,J=6.8Hz,4F),-111.4(dd,J=63.1,109.3Hz,2F),-121.3(ddt,J=6.1,13.2,18.5Hz,4F),-121.9(dt,J=9.5,19.3Hz,4F),-177.9(dd,J=33.3,109.1Hz,2F)。

[0115] 1 H NMR(400MHz,CDCl3)δ7.7(d,J=8.5Hz,4H),7.6(d,J=8.5Hz,4H)。

Claims

1. A method for preparing a compound as shown in Formula I, characterized in that, It includes the following steps: In an organic solvent, in the presence of a metallic reagent, the compound shown in Formula II undergoes an addition-elimination reaction with tetrafluoroethylene to generate the compound shown in Formula I.

2. The preparation method according to claim 1, characterized in that, It satisfies one or more of the following conditions: (1) The organic solvent is a hydrocarbon solvent and / or an ether solvent; (2) The metal reagent is an activated metal, a Grignard reagent, or an organolithium reagent; (3) The molar ratio of the metal reagent to the compound shown in Formula II is (2-4):1; (4) The molar ratio of the tetrafluoroethylene to the compound shown in Formula II is (5-20):1; (5) The molar volume ratio of the compound as shown in Formula II to the organic solvent is 0.1 to 0.5 mmol / mL; (6) The reaction is carried out under an inert gas protection, such as nitrogen protection.

3. The preparation method according to claim 2, characterized in that, It satisfies one or more of the following conditions: (1) The organic solvent is selected from one or more of n-hexane, cyclohexane, n-heptane, methylcyclohexane, 2-methylpentane, isooctane, 1,2-dimethoxyethane, diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 2-methoxyethyl ether and diethylene glycol dimethyl ether, preferably diethyl ether, tetrahydrofuran or 2-methyltetrahydrofuran; (2) The activated metal is activated magnesium powder or activated zinc powder, preferably activated magnesium powder; (3) The organolithium reagent is methyllithium, n-butyllithium or sec-butyllithium, preferably methyllithium or n-butyllithium; (4) The Grignard reagent is ethyl magnesium bromide, methyl magnesium bromide, ethyl magnesium bromide, butyl magnesium chloride or phenyl magnesium chloride, preferably methyl magnesium bromide or ethyl magnesium bromide; (5) The molar ratio of the metal reagent to the compound shown in Formula II is 2.2:1, 2.4:1, 2.5:1 or 4:1; (6) The molar ratio of the tetrafluoroethylene to the compound shown in Formula II is 5:1, 7.5:1 or 10:1; (7) The molar volume ratio of the compound as shown in Formula II to the organic solvent is 0.2 mmol / mL or 0.25 mmol / mL; (8) The concentration of the organolithium reagent is 1.2M to 2M, preferably 1.6M; (9) The concentration of the Grignard reagent is 1M to 5M, preferably 1M or 3M.

4. The preparation method according to claim 3, characterized in that, The preparation method includes the following steps: Step 1: Mix the compound shown in Formula II with the organic solvent, then add the metal reagent to react and obtain an aryl metal reagent; Step 2: The aryl metal reagent is added to the organic solvent containing tetrafluoroethylene to react and generate a compound as shown in Formula I.

5. The preparation method according to claim 4, characterized in that, It satisfies one or more of the following conditions: (1) In step one, the feeding temperature of the metal reagent is -78℃ to 25℃; (2) In step one, the metal reagent is added by dripping. (3) In step one, the reaction temperature is 0℃~70℃; (4) Step one is carried out under the protection of anhydrous and inert gas; (5) In step two, the reaction feeding temperature is -78℃ to 0℃; (6) In step two, the aryl metal reagent is added by dropping; (7) In step two, the reaction temperature is -78℃ to 0℃.

6. The preparation method according to claim 5, characterized in that, It satisfies one or more of the following conditions: (1) In step one, when the metal reagent is an organolithium reagent, the feeding temperature of the metal reagent is -78℃ to -60℃, for example -70℃; (2) In step one, when the metal reagent is an activated metal or a Grignard reagent, the feeding temperature of the metal reagent is 0℃~50℃; (3) In step one, when the metal reagent is an organolithium reagent, the reaction temperature is -5℃ to 5℃, preferably 0℃; (4) In step one, when the metal reagent is a Grignard reagent, the reaction temperature is preferably 40℃~50℃. (5) In step one, when the metal reagent is an activated metal, the reaction temperature is preferably 60℃~80℃, and more preferably 70℃. (6) Step one is carried out under anhydrous and nitrogen gas protection; (7) In step two, the reaction feeding temperature is -40℃; (8) In step two, the reaction temperature is -40℃ to 0℃.

7. The preparation method according to claim 1, characterized in that, The preparation method also includes a method for preparing the compound shown in Formula II, which includes the following steps: in an organic solvent, in the presence of metallic copper or copper salt, the compound shown in Formula III undergoes a selective coupling reaction with p-chloroiodobenzene to generate the compound shown in Formula II.

8. The preparation method according to claim 7, characterized in that, In the preparation method of the compound shown in Formula II, the selective coupling reaction satisfies one or more of the following conditions: (1) The selective coupling reaction further includes a base and a ligand; (2) The metallic copper is copper powder; (3) The copper salts are monovalent copper salts; (4) The organic solvent is selected from one or more of nitrile solvents, amide solvents, sulfoxide solvents and ether solvents; (5) The molar ratio of the metallic copper or copper salt to the compound shown in Formula III is 1:(1-20); (6) The molar ratio of the p-chloroiodobenzene to the compound shown in Formula III is (2-5):1; (7) The molar volume ratio of the compound as shown in Formula III to the organic solvent is 0.1 to 1 mmol / mL; (8) The selective coupling reaction is carried out under the protection of an inert gas; (9) The temperature of the selective coupling reaction is 30℃~160℃.

9. The preparation method according to claim 8, characterized in that, In the preparation method of the compound shown in Formula II, the selective coupling reaction satisfies one or more of the following conditions: (1) The copper salt is cuprous iodide, cuprous bromide or cuprous chloride, preferably cuprous iodide; (2) The alkali is an inorganic alkali; the inorganic alkali is preferably sodium carbonate, potassium carbonate, cesium carbonate, potassium hydroxide, potassium fluoride or potassium phosphate, and more preferably potassium carbonate, cesium carbonate or potassium fluoride; (3) The ligand is a monodentate ligand or a bidentate ligand; the monodentate ligand is preferably N-methylglycine, proline or N,N-dimethylglycine, and more preferably proline; The bidentate ligand is preferably 2,2-bipyridine, phenanthroline, or N,N'-dimethyl-1,2-ethylenediamine, more preferably 2,2-bipyridine; (3) The organic solvent is selected from one or more of acetonitrile, N-methylpyrrolidone, N,N'-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran and 1,4-dioxane, preferably acetonitrile, DMF or DMSO; (4) The molar ratio of the metallic copper or copper salt to the compound shown in Formula III is 1:20; (5) The molar ratio of the p-chloroiodobenzene to the compound shown in Formula III is 2:1; (6) The molar volume ratio of the compound as shown in Formula III to the organic solvent is 0.2 mmol / mL; (7) The molar ratio of the base to the compound shown in Formula III is (0-5):1, preferably 2:1; (8) The molar ratio of the ligand to the compound shown in Formula III is (0-1):1, preferably 0.8:1 or 0.4:1; (9) The selective coupling reaction is carried out under nitrogen protection; (10) The temperature of the selective coupling reaction is 80℃~100℃.

10. A method for preparing a compound as shown in Formula II, characterized in that, It includes the following steps: in an organic solvent, in the presence of metallic copper or a copper salt, the compound shown in Formula III undergoes a selective coupling reaction with p-chloroiodobenzene to generate the compound shown in Formula II. Preferably, the method for preparing the compound as shown in Formula II is as described in any one of claims 7-9.

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