Fluorine-containing compound as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of a fluorine-containing compound. Specifically, the invention discloses a preparation method of a compound as shown in a formula III, which comprises the following step: in a solvent, under the action of alkali, carrying out substitution reaction as shown in the specification on a compound as shown in a formula I and a compound as shown in a formula II to prepare the compound as shown in the formula III. The modified polytetrafluoroethylene prepared from the fluorine-containing functional monomer prepared by the preparation method disclosed by the invention is excellent in performance, and the fluorine-containing functional monomer prepared by the preparation method disclosed by the invention is relatively high in yield. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorochemical synthesis, and relates to fluorine-containing compounds, their preparation methods and their applications. Background Art

[0002] PTFE has high chemical stability, extremely strong high-temperature resistance, outstanding waterproof and non-sticking properties, exceptional lubricity, as well as excellent electrical insulation, aging resistance and radiation resistance, making it widely used in the fields of petrochemical industry, electronics, aviation, aerospace, semiconductor, machinery, automobile, etc. However, PTFE has defects such as poor mechanical properties, large coefficient of linear expansion, poor dimensional stability, low thermal conductivity, poor creep resistance, poor abrasion resistance, easy cold flow, low hardness, and difficulties in forming and secondary processing, which have limited its application scope to a certain extent. Although these defects can be partially modified by physical means such as reinforcement, filling, compounding and blending, the problem cannot be fundamentally solved; through continuous exploration, scientists have found a method to completely solve the above defects, that is, by copolymerizing tetrafluoroethylene (TFE) with fluorine-containing functional monomers with side groups, various fluorine-containing functional monomers with side groups are introduced into the macromolecular chain of PTFE. Copolymer-modified PTFE (such as Teflon PFA) uses fluorine-containing functional monomers of trifluorovinyl ether to copolymerize with TFE, making the main chain structure of the material very close to that of PTFE. Therefore, the physical and chemical properties and electrical properties of PTFE can be maintained, while the perfluoroalkoxy side group increases the flexibility of the polymer chain, improves the cold flow property of the material, and enables it to be molded by general processing techniques or thermoplastic processing. The copolymer-modified PTFE can not only maintain the excellent characteristics of conventional PTFE, but also endow the material with good processing properties and can meet different processing application requirements. When the content of fluorine-containing functional monomers in the modified PTFE is low, although the material still cannot be melt-processed, its processing performance is significantly improved when using a processing method similar to that of PTFE. When the content of fluorine-containing functional monomers is large, since its melt viscosity is significantly reduced, it becomes a melt-processable PTFE product. In addition to being suitable for extrusion and transfer molding grades, the copolymer-modified PTFE also has injection molding grades, which can be processed into thin-walled transparent small parts and new grades that can be dissolved in special solvents. This series of high-grade PTFE materials with special properties not only maintain the physical and mechanical properties, corrosion resistance, weather resistance and other properties of traditional PTFE, but also have the advantages of being meltable, anti-cold flow, fold resistance and good gloss. However, the types of fluorine-containing functional monomers in China are few, resulting in domestic fluorine materials mainly being in the mid- to low-end range, and further leading to a disadvantage in international competition for high-end fluorine materials. The purpose of this article is to provide a preparation method of fluorine-containing functional monomers to provide material support for the research and development of domestic high-end fluorine materials. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a new fluorine-containing functional monomer, a preparation method thereof and an application thereof in view of the lack of preparation methods of fluorine-containing functional monomers in the prior art. The modified polytetrafluoroethylene prepared from the fluorine-containing functional monomer of the present invention has excellent properties, and the yield of the fluorine-containing functional monomer prepared by the preparation method of the present invention is relatively high.

[0004] The present invention solves the above technical problems through the following technical solutions.

[0005] The present invention provides a preparation method of a compound represented by Formula III, which comprises the following steps: in a solvent, under the action of a base, a compound represented by Formula I and a compound represented by Formula II are subjected to the following substitution reaction to prepare a compound represented by Formula III, that's all.

[0006]

[0007] wherein, R is independently -H, -CN, -C(=O)OR 1 , -C(=O)R 2 , halogen, C1-C6 alkyl or C1-C6 alkoxy;

[0008] R 1 is C1-C6 alkyl;

[0009] R 2 is C6-C 10 aryl or C6-C 2-1 aryl substituted by one or more R 10 ;

[0010] R 2-1 is halogen;

[0011] n is 1, 2, 3, 4 or 5;

[0012] X is halogen.

[0013] In one embodiment, among Rs, the C1-C6 alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl, such as methyl.

[0014] In one embodiment, among Rs, the C1-C6 alkoxy is methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy or tert-butoxy, such as methoxy.

[0015] In one embodiment, among Rs, the halogen is F, Cl, Br or I, such as Br.

[0016] In one embodiment, R 1Among them, the C1-C6 alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl, such as ethyl.

[0017] In one embodiment, R 2 Among them, the C6-C 10 The aryl group is phenyl or naphthyl, such as phenyl.

[0018] In one embodiment, R 2-1 Among them, the halogen is F, Cl, Br or I, such as Cl.

[0019] In one embodiment, R is independently -H, -CN, -C(=O)OEt, -Br, -CH3 or -OCH3.

[0020] In one embodiment, n is 1, 2 or 3.

[0021] In one embodiment, the compound represented by Formula I is any one of the following compounds:

[0022]

[0023] In one embodiment, X is Br.

[0024] In one embodiment, the substitution reaction is carried out in an inert gas, and the inert gas is, for example, nitrogen.

[0025] In one embodiment, the molar ratio of the compound represented by Formula II to the compound represented by Formula I is (1 to 1.5):1, such as 1.1:1.

[0026] In one embodiment, the solvent is a polar aprotic solvent, for example, selected from one or more of amide solvents, sulfoxide solvents, nitrile solvents and ether solvents. The amide solvent is, for example, DMF, the sulfoxide solvent is, for example, dimethyl sulfoxide, the nitrile solvent is, for example, adiponitrile, and the ether solvent can be selected from one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether.

[0027] In one embodiment, the solvent is DMF, DMSO, adiponitrile, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether.

[0028] In one embodiment, the volume molar ratio of the solvent to the compound represented by Formula I is 1 to 2 mL / mmol, such as 1.5 mL / mmol.

[0029] In one embodiment, the base is selected from alkali metals, alkali metal hydrides, alkali metal carbonates, alkali metal hydroxides, alkali metal bicarbonates, alkyl lithiums and One or more of the following, where R a Each is independently a C1-C4 alkyl group (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl), M is an alkali metal (e.g., Na, K or Li); preferably, the alkali is selected from an alkali metal, an alkali metal hydride, an alkyl lithium and One or more of .

[0030] Preferably, the alkali metal element is sodium and / or potassium.

[0031] Preferably, the alkali metal hydride is NaH and / or NaK, such as NaH.

[0032] Preferably, the alkali metal carbonate is selected from one or more of sodium carbonate, potassium carbonate, lithium carbonate and cesium carbonate.

[0033] Preferably, the alkali metal hydroxide is selected from one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide.

[0034] Preferably, the alkali metal bicarbonate is sodium bicarbonate and / or potassium bicarbonate.

[0035] Preferably, the alkyl lithium is n-butyl lithium and / or tert-butyl lithium.

[0036] Preferably, the Selected from One or more of .

[0037] In one embodiment, the base is selected from Na, K, NaH, KH, n-butyl lithium, tert-butyl lithium, One or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, lithium carbonate, cesium carbonate, lithium hydroxide, sodium hydroxide and potassium hydroxide, preferably Na, K, NaH, KH, n-butyl lithium, tert-butyl lithium, One or more of, more preferably NaH.

[0038] In one embodiment, the molar ratio of the base to the compound of formula I is (1-1.5):1, for example 1.1:1.

[0039] In one embodiment, the reaction temperature of the substitution reaction is 40-60°C, for example 50°C.

[0040] The reaction time of the substitution reaction is until the compound shown in Formula I reacts completely.

[0041] In one embodiment, the reaction time of the substitution reaction is 10 to 15 h, such as 12 h.

[0042] In one embodiment, after the compound represented by Formula I is mixed with the base and the solvent (for example, a mixed solution of the compound represented by Formula I and the solvent is added dropwise to the base, and the temperature during mixing can be -5 to 0 °C), it is then subjected to a substitution reaction with the compound represented by Formula II. Preferably, after the compound represented by Formula I is mixed with the base and the solvent, it is stirred at 20 to 30 °C (such as 25 °C) for 0.5 to 1.5 h (such as 1 h).

[0043] After the substitution reaction is completed, it can be post-treated by conventional post-treatment methods in this field, such as quenching and extracting the reaction solution. The reagent used for quenching can be an aqueous ammonium chloride solution.

[0044] The present invention also provides a compound represented by Formula III according to any one of the above embodiments.

[0045] In one embodiment, the compound represented by Formula III is any one of the following compounds:

[0046]

[0047]

[0048] The present invention also provides an application of the compound represented by Formula III according to any one of the above embodiments in the preparation of modified polytetrafluoroethylene.

[0049] On the basis of conforming to common knowledge in the art, the above preferred conditions can be arbitrarily combined to obtain various preferred examples of the present invention.

[0050] The reagents and raw materials used in the present invention are all commercially available.

[0051] The positive and progressive effects of the present invention are as follows: The modified polytetrafluoroethylene prepared from the fluorine-containing functional monomer of the present invention has excellent performance, and the yield of the fluorine-containing functional monomer prepared by the preparation method of the present invention is relatively high. Specific Embodiments

[0052] The present invention will be further illustrated by the following examples, but the present invention is not limited to the scope of the examples. The experimental methods without specific conditions in the following examples are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0053] Synthesis Route:

[0054] Typical Operations of Examples

[0055]

[0056] Under nitrogen protection, add NaH (2.2 mol) into the reaction flask. Place the reaction flask in an ice-water bath. Slowly add a mixed solution of substituted phenol (2 mmol) and anhydrous DMF (3 mL) to the reaction flask using a syringe. After addition, restore to room temperature and continue the reaction for 1 hour. Add the fluorine-containing building block BrCF2CF2OCF═CF2 (II) (607 mg, 2.2 mmol) (dissolve the fluorine-containing building block with 1 mL of DMF) to the reaction flask. Seal the reaction flask and heat it at 50 °C in an oil bath for 12 hours. Quench the reaction system by adding an aqueous ammonia chloride solution, add 5 mL of water, extract with ethyl acetate, and after drying, remove the solvent and perform column chromatography to obtain the target product.

[0057]

[0058] Example 1:

[0059] In Example 1, the fluorine-containing functional monomer prepared is:

[0060] The substrate is phenol, and the separation yield is 86%.

[0061] 19 F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0062] 1 H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0063] Example 2:

[0064] In Example 2, the fluorine-containing functional monomer prepared is:

[0065] The substrate is phenol, the solvent is changed to diethylene glycol dimethyl ether, and other conditions remain unchanged. The separation yield is 78%.

[0066] 19 F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0067] 11H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0068] Example 3:

[0069] In Example 3, the fluorine-containing functional monomer prepared is:

[0070] The substrate is phenol, the solvent is changed to tetraethylene glycol dimethyl ether, and the others remain unchanged. The separation yield is 80%.

[0071] 19 19F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0072] 1 1H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0073] Example 4:

[0074] In Example 4, the fluorine-containing functional monomer prepared is:

[0075] The substrate is phenol, the solvent is changed to DMSO, and the others remain unchanged. The separation yield is 73%.

[0076] 19 19F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0077] 1 1H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0078] Example 5:

[0079] In Example 5, the fluorine-containing functional monomer prepared is:

[0080] The substrate is phenol, the solvent is changed to adiponitrile, and the others remain unchanged. The separation yield is 63%.

[0081] 19 F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0082] 1 H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0083] Example VI:

[0084] In Example VI, the prepared fluorine-containing functional monomer is:

[0085] The substrate is phenol, the base is changed to KH, and the others remain unchanged. The separation yield is 82%.

[0086] 19 F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0087] 1 H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0088] Example VII:

[0089] In Example VII, the prepared fluorine-containing functional monomer is:

[0090] The substrate is phenol, the base is changed to KHMDS, and the others remain unchanged. The separation yield is 79%.

[0091] 19 F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0092] 11H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0093] Example VIII:

[0094] In Example VIII, the fluorine-containing functional monomer prepared is:

[0095] The substrate is phenol, the base is replaced with NaHMDS, and the others remain unchanged. The separation yield is 76%.

[0096] 19 19F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0097] 1 1H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0098] Example IX:

[0099] In Example IX, the fluorine-containing functional monomer prepared is:

[0100] The substrate is phenol, the base is replaced with LiHMDS, and the others remain unchanged. The separation yield is 80%.

[0101] 19 19F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.5 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0102] 1 1H NMR (400 MHz, CDCl3) δ ppm 7.28 (dd, J = 8.7, 7.4 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 6.90 (dd, J = 8.7, 1.0 Hz, 2H).

[0103] Example X:

[0104] In Example X, the fluorine-containing functional monomer prepared is:

[0105] The substrate is the corresponding substituted phenol, and the separation yield is 76%.

[0106] 19 19F NMR (376 MHz, CDCl3) δ ppm -87.7 (m, 4F), -112.4 (m, 1F), -120.2 (m, 1F), -134.3 (m, 1F).

[0107] 1 1H NMR (400 MHz, CDCl3) δ ppm 7.76 (d, J = 8.8 Hz, 2H), 7.70 (d, J = 8.5 Hz, 2H), 7.46 (d, J = 8.5 Hz, 2H), 6.97 (d, J = 8.8 Hz, 2H).

[0108] Example XI:

[0109] In Example XI, the fluorine-containing functional monomer prepared is:

[0110] The substrate is p-methylphenol, and the isolated yield is 80%.

[0111] 19 19F NMR (376 MHz, CDCl3) δ ppm -88.4 (m, 4F), -113.4 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0112] 1 1H NMR (400 MHz, CDCl3) δ ppm 7.17 (d, J = 8.5 Hz, 2H), 7.11 (d, J = 8.6 Hz, 2H), 2.35 (s, 3H).

[0113] Example XII:

[0114] In Example XII, the fluorine-containing functional monomer prepared is:

[0115] The substrate is p-ethyl formate phenol, and the isolated yield is 92%.

[0116] 19 19F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.2 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0117] 1 1H NMR (400 MHz, CDCl3) δ ppm 8.02 (d, J = 8.9 Hz, 2H), 6.92 (d, J = 8.9 Hz, 2H), 4.36 (q, J = 7.0 Hz, 2H), 1.38 (t, J = 7.0 Hz, 3H).

[0118] Example XIII:

[0119] In Example XIII, the fluorine-containing functional monomer prepared is:

[0120] The substrate is p-bromophenol, and the separation yield is 73%.

[0121] 19 F NMR (376 MHz, CDCl3) δ ppm -88.2 (m, 4F), -113.0 (m, 1F), -121.1 (m, 1F), -135.2 (m, 1F).

[0122] 1 H NMR (400 MHz, CDCl3) δ ppm 7.45 (d, J = 8.3 Hz, 2H), 7.08 (d, J = 8.3 Hz, 2H).

[0123] Example XIV:

[0124] In Example XIV, the fluorine-containing functional monomer prepared is:

[0125] The substrate is p-bromophenol, and the separation yield is 85%.

[0126] 19 F NMR (376 MHz, CDCl3) δ ppm -88.7 (m, 4F), -113.4 (m, 1F), -121.2 (m, 1F), -135.5 (m, 1F).

[0127] 1 H NMR (400 MHz, CDCl3) δ ppm 7.58 (d, J = 8.8 Hz, 2H), 6.94 (d, J = 8.8 Hz, 2H).

[0128] Example XV:

[0129] In Example XV, the fluorine-containing functional monomer prepared is:

[0130] The substrate is m-ethyl formate phenol, and the separation yield is 89%.

[0131] 19 F NMR (376 MHz, CDCl3) δ ppm -88.7 (m, 4F), -113.1 (m, 1F), -121.2 (m, 1F), -135.3 (m, 1F).

[0132] 11H NMR (400 MHz, CDCl3) δ ppm 7.64 (d, J = 7.7 Hz, 1H), 7.53 (s, 1H), 7.32 (t, J = 7.8 Hz, 1H), 7.07 (dd, J = 8.1, 1.4 Hz, 1H), 4.35 (q, J = 7.0 Hz, 2H), 1.38 (t, J = 7.0 Hz, 3H).

[0133] Example XVI:

[0134] In Example XVI, the fluorine-containing functional monomer prepared is:

[0135] The substrate is p-methoxyphenol, and the separation yield is 78%.

[0136] 19 19F NMR (376 MHz, CDCl3) δ ppm -88.8 (m, 4F), -113.5 (m, 1F), -121.4 (m, 1F), -135.4 (m, 1F).

[0137] 1 1H NMR (400 MHz, CDCl3) δ ppm 7.16 (d, J = 8.9 Hz, 2H), 6.90 (d, J = 8.9 Hz, 2H), 3.82 (s, 3H).

[0138] Example XVII:

[0139] In Example XVII, the fluorine-containing functional monomer prepared is:

[0140] The substrate is 3,4,5-trimethoxyphenol, and the separation yield is 81%.

[0141] 19 19F NMR (376 MHz, CDCl3) δ ppm -88.6 (m, 4F), -113.4 (m, 1F), -121.1 (m, 1F), -135.3 (m, 1F).

[0142] 1 1H NMR (400 MHz, CDCl3) δ ppm 6.13 (s, 2H), 3.82 (s, 6H), 3.78 (s, 3H).

[0143] Test on the Effect of Fluorine-containing Functional Monomer

[0144] During the telomerization of tetrafluoroethylene, high-molecular-weight modified PTFE can be prepared by adding one or more modified functional monomers prepared by the present invention (for the preparation of modified PTFE, refer to Example 3 of Patent: CN108219053A, and the modified monomers therein can be replaced with the modified functional monomers of the present invention). The orderly incorporation of the modified functional monomers improves the bonding performance of PTFE and simultaneously enhances the crystallization processing performance. While maintaining a high dielectric performance (Df), the bonding force (peel strength) and processing compatibility of this product are higher than those of foreign products. In particular, its bonding force (peel strength) can reach 4.0 N / mm, far exceeding that of foreign counterparts (the peel strength is 2.0 N / mm), greatly improving the problem of copper foil detachment that often occurs during the deep processing or installation welding of copper clad laminate materials, and having an absolute market advantage compared with similar products.

[0145] Peel strength test method: IPC-TM-650 2.4.8C:1994 (copper foil peel strength test after thermal stress on the sample)

[0146] Test conditions: The vertical tensile rate is 50 mm / min. Thermal stress treatment conditions: 288 °C, 10 s, once.

[0147] Performance Peeling strength (N / mm) Df Modified PTFE 4.0 0.001 Foreign competing products 2.0 0.001 。

Claims

1. A method for preparing a compound represented by Formula III, which comprises the following steps: In a solvent, under the action of a base, the compound represented by Formula I reacts with the compound represented by Formula II in the following substitution reaction to prepare the compound represented by Formula A, that's all. Among them, R is independently -H, -CN, -C(=O)OR 1 , -C(=O)R 2 , a halogen, a C1-C6 alkyl or a C1-C6 alkoxy group; R 1 is a C1-C6 alkyl group; R 2 is C6-C 10 aryl or C6-C aryl substituted by one or more R 2-1 groups; 10 aryl; R 2-1 is a halogen; n is 1, 2, 3, 4 or 5; X is a halogen.

2. The preparation method of the compound shown in Formula III as described in Claim 1, characterized in that, It satisfies one or more of the following conditions: (1) In R, the C1-C6 alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl, such as methyl; (2) In R, the C1-C6 alkoxy is methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy or tert-butoxy, such as methoxy; (3) In R, the halogen is F, Cl, Br or I, such as Br; (4)R 1 Among them, the C1-C6 alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl, such as ethyl; (5)R 2 Among them, the C6-C 10 aryl is phenyl or naphthyl, such as phenyl; (6)R 2-1 In this case, the halogen is F, Cl, Br or I, such as Cl.

3. The preparation method of the compound shown in Formula III as described in Claim 2, characterized in that, It satisfies one or more of the following conditions: (1)R is independently -H, -CN, -C(=O)OEt, -Br, -CH3 or -OCH3; (2) n is 1, 2 or 3; (3) X is Br.

4. The preparation method of the compound shown in Formula III according to any one of claims 1-3, characterized in that, It satisfies one or more of the following conditions: (1) The compound represented by Formula I is any one of the following compounds: (2) The substitution reaction is carried out in an inert gas; (3) The molar ratio of the compound represented by Formula II to the compound represented by Formula I is (1-1.5):1; (4) The solvent is a polar aprotic solvent, such as selected from one or more of amide solvents, sulfoxide solvents, nitrile solvents and ether solvents; (5) The volume molar ratio of the solvent to the compound represented by Formula I is 1-2 mL / mmol (6) The base is selected from alkali metals, alkali metal hydrides, alkali metal carbonates, alkali metal hydroxides, alkali metal bicarbonates, alkyl lithiums and One or more of the following, where R a Each is independently a C1-C4 alkyl group, and M is an alkali metal; (7) The molar ratio of the base to the compound represented by Formula I is (1-1.5):1, such as 1.1:1; (8) The reaction temperature of the substitution reaction is 40-60 °C, such as 50 °C; (9) After the compound represented by Formula I is mixed with the base and the solvent (for example, the mixed solution of the compound represented by Formula I and the solvent is added dropwise to the base, and the temperature during mixing can be -5 to 0 °C), then it reacts with the compound represented by Formula II in a substitution reaction; preferably, after the compound represented by Formula I is mixed with the base and the solvent, it is stirred at 20-30 °C (such as 25 °C) for 0.5-1.5 h (such as 1 h).

5. The preparation method of the compound shown in Formula III as described in claim 4, characterized in that, It satisfies one or more of the following conditions: (1) The base selected from alkali metal simple substances, hydrides of alkali metals, carbonates of alkali metals, hydroxides of alkali metals, bicarbonates of alkali metals, alkyllithiums and one or more of them, and the alkali metal simple substance is sodium and / or potassium; (2) The base selected from the group consisting of alkali metal elements, hydrides of alkali metals, carbonates of alkali metals, hydroxides of alkali metals, bicarbonates of alkali metals, alkyllithiums, and one or more of the above, wherein the hydride of the alkali metal is NaH and / or NaK, such as NaH; (3) The base described above is selected from one or more of alkali metal simple substances, hydrides of alkali metals, carbonates of alkali metals, hydroxides of alkali metals, bicarbonates of alkali metals, alkyllithiums, and one or more of the above, and the carbonate of the alkali metal is selected from one or more of sodium carbonate, potassium carbonate, lithium carbonate, and cesium carbonate; (4) The base described above is selected from one or more of elemental alkali metals, hydrides of alkali metals, carbonates of alkali metals, hydroxides of alkali metals, bicarbonates of alkali metals, alkyllithiums and ; the hydroxides of the alkali metals are selected from one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; (5) The base selected from alkali metal elements, hydrides of alkali metals, carbonates of alkali metals, hydroxides of alkali metals, bicarbonates of alkali metals, alkyllithiums and one or more of the above, and the bicarbonate of alkali metal is sodium bicarbonate and / or potassium bicarbonate; (6) The base selected from alkali metal simple substances, hydrides of alkali metals, carbonates of alkali metals, hydroxides of alkali metals, bicarbonates of alkali metals, alkyllithiums and one or more of them, and the alkyllithium is n-butyllithium and / or tert-butyllithium; (7) The selected from one or more of.

6. The preparation method of the compound shown in Formula III as described in claim 4, characterized in that, It satisfies one or more of the following conditions: (1) When the substitution reaction is carried out in an inert gas, the inert gas is nitrogen; (2) The molar ratio of the compound represented by Formula II to the compound represented by Formula I is 1.1:1; (3) When the solvent is selected from one or more of amide solvents, sulfoxide solvents, nitrile solvents and ether solvents, the amide solvent is DMF; (4) When the solvent is selected from one or more of amide solvents, sulfoxide solvents, nitrile solvents and ether solvents, the sulfoxide solvent is dimethyl sulfoxide; (5) When the solvent is selected from one or more of amide solvents, sulfoxide solvents, nitrile solvents, and ether solvents, the nitrile solvent is adiponitrile; (6) When the solvent is selected from one or more of amide solvents, sulfoxide solvents, nitrile solvents, and ether solvents, the ether solvent is selected from one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether; (7) The volume molar ratio of the solvent to the compound shown in Formula I is 1.5 mL / mmol; (8) wherein R a is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl; (9) wherein M is Na, K or Li; (10) The base is an alkali metal element, a hydride of an alkali metal, an alkyllithium or 7. The preparation method of the compound shown in Formula III as described in Claim 1, characterized in that, It satisfies one or more of the following conditions: (1) The solvent is DMF, DMSO, adiponitrile, DMF, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, or tetraethylene glycol dimethyl ether; (2) The base selected from Na, K, NaH, KH, n-butyllithium, tert-butyllithium, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, lithium carbonate, cesium carbonate, lithium hydroxide, sodium hydroxide and potassium hydroxide, one or more of them, preferably one or more of Na, K, NaH, KH, n-butyllithium, tert-butyllithium, one or more of them, and more preferably NaH.

8. A compound shown in Formula III: Among them, R and n are defined as described in any one of claims 1-4.

9. The compound of formula III as claimed in claim 8, wherein, It is any one of the following compounds:

10. Use of the compound shown in Formula III as described in claim 8 or 9 in the preparation of modified polytetrafluoroethylene.

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