Organic boron salt olefin polymerization promoter as well as preparation method and application thereof

Abstract

The invention provides an organic boron salt olefin polymerization cocatalyst as well as a preparation method and application thereof, and belongs to the technical field of olefin polymerization catalysts. The organic boron salt olefin polymerization promoter provided by the invention has a structure as shown in a formula I. In the formula I, Ct < + > is a cation capable of enabling a metal alkyl chain to be subjected to alkyl elimination, and R1 is independently selected from carbon or silicon atoms; r2, R3 and R4 are independently selected from hydrogen, alkyl or phenyl respectively; the organic boron salt olefin polymerization cocatalyst provided by the invention is mainly used in olefin polymerization reaction. Compared with a traditional perfluorotetraphenylboron promoter [Ct] + [B (C6F4-R-p) 4]-, the organic boron promoter [Ct] + [B (C6F4-R-p) 4]-has better solubility in non-polar straight-chain alkane and cycloalkane, metallocene and non-metallocene main catalysts can be efficiently activated, a more loose anion-cation pair polymerization active center is formed, and olefin coordination and polymerization are facilitated. And the formula I of the # imgabs0 # is shown in the specification.

Description

Technical Field

[0001] The invention belongs to the technical field of olefin polymerization catalysts, and in particular relates to an organic boron salt olefin polymerization co-catalyst and a preparation method and application thereof. Background Art

[0002] Polyolefin resins are generally made from different olefin monomers through catalytic polymerization technology. The catalytic systems commonly used in industry currently mainly include Ziegler-Natta (ZN) catalyst systems and metallocene catalyst systems. Compared with multi-phase and multi-site ZN catalysts, metallocene catalysts with a single active center have higher catalyst activity, excellent copolymerization performance, and a narrower molecular weight distribution of the polymerized products. With the continuous demand for high-end polyolefin resins (such as POE, COC, and COP, etc.) in the polyolefin market, metallocene catalysts, as the mainstream catalysts for the production of such polyolefin products, are one of the important directions for the future of the polyolefin industry.

[0003] The metallocene catalytic system is generally composed of a metallocene main catalyst and a Lewis acid cocatalyst. The activation process is that the metallocene alkyl compound interacts with the Lewis acid cocatalyst to form an ion pair of a metallocene alkyl cation and a Lewis acid anion. This ion pair can realize the insertion chain growth process of olefins in the metal center and B -H chain elimination process, thereby catalyzing olefin polymerization. The charge binding force between metallocene ion pairs, that is, the tightness between anion and cation pairs, directly affects the activity and copolymerization performance of metallocene catalysts, so Lewis acids as co-catalysts play an important role in the development of metallocene catalyst technology.

[0004] At present, most Lewis acid additives that are effectively matched with metallocene catalysts in industry are methylaluminoxane (MAO) and its modified derivatives. However, in industrial applications, due to the high price of MAO additives and their flammable properties in air, the cost of polyolefin resin products will increase. Therefore, developing cheap MAO alternative catalysts has become one of the effective means to reduce the price of such polyolefin products.

[0005] Perfluorotetraaryl borate is a new generation of cocatalysts that can replace MAO. They can react with metallocene dialkyl compounds to produce monoalkyl metallocene perfluorotetraaryl borate ion pairs, which can then catalyze olefin polymerization. On the one hand, the strong electron-withdrawing effect of fluorine atoms reduces the electron cloud density on the aromatic group, effectively avoiding the complexation of the aromatic π bond on the metallocene active center; on the other hand, the electron-withdrawing effect of fluorine atoms weakens the electronegativity of the borate anion, which can greatly weaken the interaction between the anion and cation pairs, and at the same time relatively increase the Lewis acidity of the metallocene active center, which is beneficial to the coordination insertion of the olefin π bond.

[0006] The perfluorotetraarylboric acid co-catalyst currently used in industry is mostly perfluorotetraphenylborane [B(C 6 F 5 ) 4 ] - As anion, cation is inorganic metal ion, triphenyl carbon cation or protonated organic ammonium ion. Commonly used organic boron additives mainly include M[B(C 6 F 5 ) 4 ](M=Li, Na, K), [PhNHMe 2 ][B(C 6 F 5 ) 4 ] and [Ph 3 C][B(C 6 F 5 ) 4 ], etc. In industrial olefin solution polymerization, the solvent is usually selected as a non-polar hydrocarbon solvent. However, the organic boron additive M[B(C 6 F 5 ) 4 ](M=Li, Na, K), [PhNHMe 2 ][B(C 6 F 5 ) 4 ] and [Ph 3 C][B(C 6 F 5 ) 4 ] There is a common problem of low solubility in alkane solvents, which makes them react unevenly when activating metallocenes, resulting in a decrease in the effective concentration of activated cationic metallocenes in the polymerization reactor, thereby reducing the overall catalyst activity and increasing the cost of catalyst use. This has limited the current scope of application of organoboron additives in industry to a certain extent.

[0007] In view of the low solubility of boron salt co-catalysts in hydrocarbon solvents, relevant technologies at home and abroad have also proposed solutions. The borate cation part (triphenylcarbon or protonated organic amine) is modified, and a long-chain alkyl group is introduced into the cation by technical means, thereby improving the solubility of the entire borate in hydrocarbon solvents. Introducing long-chain alkyl groups into the aromatic hydrocarbon group of the triphenylcarbon cation can effectively improve its solubility (CN 113527341A, CN 111971311B); using protonated long-chain organic amines (ethers) as cations can also improve the solubility of borates in hydrocarbon solvents (CN115279774A, CN113164932A). However, most of the above schemes are based on [B(C 6 F 5 ) 4 ] -as the borate anion. In addition, perfluorotetraphenylborane [B(C 6 F 5 ) 4 ] - As the counter ion of metallocene alkyl cation, the metallocene active center and [B(C 6 F 5 ) 4 ] - The fluorine atoms on the metal also have a certain weak coordination effect, which creates a certain energy barrier for the coordination and reaction of olefins at the metal center, thereby reducing the catalytic efficiency. Especially in the copolymerization of multiple olefins, it may hinder the coordination and insertion of the second olefin, thereby reducing the insertion rate of the second olefin in the polymer. Summary of the invention

[0008] In order to solve the problem of low solubility of organic boron salt olefin polymerization catalyst in hydrocarbons in the prior art and to further weaken the interaction between anion and cation pairs of olefin polymerization catalyst, the present invention provides an anion [B(Ar-F) 4 ] is a para-modified organic boron salt of fluoroaromatic hydrocarbons and its preparation method, and its application in olefin polymerization reaction.

[0009] The present invention provides an organic boron salt olefin polymerization co-catalyst having a structure as shown in Formula I: Formula I; Among them, Ct + It is a cation that can cause alkyl elimination of metal alkyl chains, R 1 R is independently selected from carbon or silicon atoms; 2 , R 3 , R 4 are independently selected from hydrogen, alkyl or phenyl.

[0010] Furthermore, Ct + Selected from triarylmethyl carbocations or protonated organic amine ions.

[0011] Further, the triarylmethyl carbocation is selected from triphenylmethyl carbocation or tri(alkylated phenyl)methyl carbocation derivatives; The organic amines include primary amines, secondary amines or tertiary amines and their derivatives.

[0012] Furthermore, R 2 , R 3 , R 4 Each of the following is independently selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, cyclopentyl, cyclohexyl or phenyl.

[0013] The present invention also provides a method for preparing any of the above-mentioned organic boron salt olefin polymerization co-catalysts, comprising the following steps: 1) 1,4-dibromotetrafluorobenzene reacts with alkyl lithium or Grignard reagent to generate corresponding p-bromotetrafluorophenyl lithium or p-bromotetrafluorophenyl Grignard reagent; then reacts with halogen silane or halogenated hydrocarbon in situ to generate p-substituted tetrafluorobromobenzene derivative; 2) the para-substituted tetrafluorobromobenzene derivative is reacted with an alkyl lithium or a Grignard reagent to generate a corresponding phenyl metal reagent, which is then reacted in situ with a boron halide to generate an organic lithium borate or an organic magnesium borate with a large para-position steric substitution; 3) The above-mentioned organic borate lithium or organic borate magnesium with bulky steric substituted para position reacts with protonated organic amine or triaryl chloromethane to obtain an organic boron salt olefin polymerization cocatalyst.

[0014] Furthermore, in step 1), the molar ratio of 1,4-dibromotetrafluorobenzene, p-bromotetrafluorophenyl lithium or p-bromotetrafluorophenyl Grignard reagent, and halogenated silane or halogenated hydrocarbon is 1:0.5-1.5:0.5-1.5; In step 2), the molar ratio of the para-substituted tetrafluorobromobenzene derivative, the alkyl lithium or Grignard reagent, and the boron halide is 1:0.5-1.5:0.1-0.35; In step 3), the molar ratio of the para-position sterically hindered organic lithium borate or organic magnesium borate to the protonated organic amine or triaryl chloromethane is 1:0.5-2.0.

[0015] The present invention also proposes the use of any of the above-mentioned organic boron salt olefin polymerization co-catalysts in olefin polymerization reactions.

[0016] Further, the main catalyst for olefin polymerization reaction acting together with the above-mentioned co-catalyst includes a metal organic complex precursor that can form a cationic metal polymerization active center; Preferably, the main catalyst used for olefin polymerization reaction and co-acting with the above-mentioned co-catalyst is a metallocene compound or a non-metallocene compound for olefin polymerization. Further, the reaction raw material monomers for olefin polymerization include linear, branched or cyclic olefins or diolefins; Preferably, the reaction raw material monomers for olefin polymerization reaction include at least one of ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, norbornene, norbornadiene, vinyl norbornene, ethylidene norbornene monomer, 1,5-hexadiene, 1,6-heptadiene, and 1,7-octadiene.

[0017] Furthermore, the solvent used for dissolving the organic boron salt in the olefin polymerization reaction includes at least one of benzene, toluene, xylene, chlorobenzene, aromatic derivatives, pentane, hexane, heptane, decane, cyclohexane, methylcyclohexane and branched alkanes.

[0018] The present invention has the following advantages: The organic boron salt olefin polymerization co-catalyst proposed by the present invention is modified for perfluorotetraphenylborate anion, and a large steric hindrance group is introduced at the para position of the phenyl group connected to the boron atom, thereby reducing the polarity of the perfluorotetraphenylborate anion and improving the solubility of perfluorotetraphenylborate in hydrocarbons, which is conducive to the efficient formation of olefin polymerization active centers. In addition, the introduced large steric hindrance substituent increases the steric hindrance of the anion at the same time, weakens the charge effect of the catalyst cation active center and the boron salt anion through the steric hindrance effect, is conducive to the formation of loose anion and cation pairs, and facilitates the coordination insertion and alkyl elimination reaction of olefins in the catalyst active center. When the borate of the present invention is used as a co-catalyst to catalyze the olefin polymerization system, the activation efficiency is high, the stability of the catalyst is better, and the polymerization activity is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 The organic boron olefin cocatalyst B3 obtained in Example 3 of the present invention is 1 HNMR spectra; Figure 2 The organic boron olefin cocatalyst B6 obtained in Example 6 of the present invention is 1 HNMR spectra; Figure 3 The organic boron olefin cocatalyst B9 obtained in Example 9 of the present invention 1 HNMR spectrum. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0022] The inventors of the present application have found that in the case of fluorotetraphenylborane [B(Ar-F) 4 ] -The introduction of a non-polar functional group with large steric hindrance on the anion can further weaken the interaction between the anion and cation pairs of the olefin polymerization catalyst through the steric hindrance effect of the substituent, which is beneficial to the coordination and reaction of the olefin π bond and improves the catalyst performance. In addition, the introduction of a large steric hindrance alkane substituent into the anion [B(Ar-F) 4 ] - The addition of ions to aromatic hydrocarbons can improve the solubility of ion-pair olefin polymerization catalysts in alkanes, making it easy to form a uniform solution polymerization system, which is beneficial to improving the activity of the catalyst.

[0023] The embodiment of the present invention provides an organic boron salt olefin polymerization co-catalyst having a structure as shown in Formula I: Formula I; Among them, Ct + It is a cation that can cause alkyl elimination of metal alkyl chains, R 1 R is independently selected from carbon or silicon atoms; 2 , R 3 , R 4 are independently selected from hydrogen, alkyl or phenyl.

[0024] The organic boron salt olefin polymerization co-catalyst and its preparation method and application proposed in the embodiments of the present invention modify the benzene of the fluorophenyl organic boron anion by introducing a large sterically hindered alkyl group at the para position, thereby solving the problem of low solubility of traditional organic boron additives in hydrocarbons. At the same time, the steric effect of the substituent further stretches the distance between the catalyst anion and cation pairs, weakens the interaction force, and thus improves the polymerization performance of the catalyst.

[0025] In one embodiment of the present invention, Ct + Selected from triarylmethyl carbocations or protonated organic amine ions.

[0026] In a preferred embodiment of the present invention, the triarylmethyl carbocation is selected from triphenylmethyl carbocation or tri(alkylated phenyl)methyl carbocation derivatives.

[0027] In a preferred embodiment of the present invention, the organic amine includes primary amine, secondary amine or tertiary amine and derivatives thereof. Specifically, the organic amine includes primary amine and derivatives thereof, secondary amine and derivatives thereof or tertiary amine and derivatives thereof. For example, the protonated organic amine ion includes protonated N, N-dimethylaniline ion and protonated di(octadecyl)methylamine ion. In one embodiment of the present invention, R 2 , R 3 , R 4 Each of the following is independently selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, cyclopentyl, cyclohexyl or phenyl.

[0028] On the other hand, an embodiment of the present invention further provides a method for preparing any of the above-mentioned organic boron salt olefin polymerization co-catalysts, comprising the following steps: 1) 1,4-dibromotetrafluorobenzene reacts with alkyl lithium or Grignard reagent to generate corresponding p-bromotetrafluorophenyl lithium or p-bromotetrafluorophenyl Grignard reagent; then reacts with halogen silane or halogenated hydrocarbon in situ to generate p-substituted tetrafluorobromobenzene derivative; 2) the para-substituted tetrafluorobromobenzene derivative is reacted with an alkyl lithium or a Grignard reagent to generate a corresponding phenyl metal reagent, which is then reacted in situ with a boron halide to generate an organic lithium borate or an organic magnesium borate with a large para-position steric substitution; 3) The above-mentioned organic borate lithium or organic borate magnesium with bulky steric substituted para position reacts with protonated organic amine or triaryl chloromethane to obtain an organic boron salt olefin polymerization cocatalyst.

[0029] Preferably, in step 1), the reaction time is 20 min to 5 h; the reaction temperature is -100 o C~50 o C; the in-situ reaction time is 1h to 20h; the in-situ reaction temperature is -100 o C~50 o C.

[0030] Preferably, in step 1), the molar ratio of 1,4-dibromotetrafluorobenzene, p-bromotetrafluorophenyl lithium or p-bromotetrafluorophenyl Grignard reagent, and halogenated silane or halogenated hydrocarbon is 1:0.5-1.5:0.5-1.5. Preferably, in step 2), the reaction time is 20 min to 5 h, and the reaction temperature is -100 o C~50 o C; the in-situ reaction time is 1h to 20h; the reaction temperature is -100 o C~80 o C. Preferably, in step 2), the molar ratio of the para-substituted tetrafluorobromobenzene derivative, the alkyl lithium or Grignard reagent, and the boron halide is 1:0.5-1.5:0.1-0.35. The halogen element of the boron halide is selected from Cl, F, and Br.

[0031] Preferably, in step 3), the reaction time is 20 min to 10 h; the reaction temperature is 0 o C~60 o C. Preferably, in step 3), the molar ratio of the para-hindered organic lithium borate or organic magnesium borate to the protonated organic amine or triaryl methyl chloride is 1:0.5-2.0. The method for preparing the organic boron salt olefin polymerization co-catalyst proposed in the embodiment of the present invention has the following reaction formula: .

[0032] On the other hand, the embodiments of the present invention also propose the use of any of the above-mentioned organic boron salt olefin polymerization co-catalysts in olefin polymerization reactions. The organic boron salt olefin polymerization co-catalyst proposed in the present invention is a type of perfluorotetraphenylborate substituted with a large steric group at the para position, which has good solubility in aromatic or alkane solvents, can efficiently activate the metallocene main catalyst, and form a looser anion-cation pair polymerization active center, which is easy to coordinate and polymerize olefins. In one embodiment of the present invention, the main catalyst used for olefin polymerization reaction and the above-mentioned co-catalyst comprises a metal organic complex precursor that can form a cationic metal polymerization active center. Preferably, the main catalyst used for olefin polymerization reaction and the above-mentioned co-catalyst is a metallocene compound or a non-metallocene compound for olefin polymerization. In the olefin polymerization catalyst system, the organic boron salt olefin polymerization co-catalyst reacts with the olefin polymerization main catalyst for activation, efficiently forming a stable olefin polymerization active center for catalyzing olefin polymerization.

[0033] In the embodiment of the present invention, the alkyl aluminum can also be mixed with the metal organic complex and the organic boron salt to generate a cationic olefin polymerization active center through an alkyl elimination reaction.

[0034] Preferably, the ligands eliminated by the metal organic complex include alkanes, halogens, amino groups or alkoxy groups.

[0035] Preferably, the alkyl aluminum includes trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, tri-n-octylaluminum, methylaluminoxane (MAO) and modified methylaluminoxane (MMAO). In one embodiment of the present invention, the reaction raw material monomers for olefin polymerization include linear, branched or cyclic olefins or dienes. Preferably, the reaction raw material monomers for olefin polymerization include ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, norbornene, norbornadiene, vinyl norbornene, ethylidene norbornene monomers, 1,5-hexadiene, 1,6-heptadiene, 1, at least one of 7-octadiene. In an embodiment of the present invention, the olefin polymerization catalyst system constructed by the organic boron salt can be used for the polymerization of one or more olefin monomers.

[0036] In a preferred embodiment of the present invention, the olefin polymerization is a polymerization reaction of ethylene and at least one comonomer having 4 to 8 carbon atoms. Preferably, the comonomer includes at least one of 1-butene, 4-methyl-1-pentene, 1-hexene or 1-octene. More preferably, the comonomer includes 1-hexene and 1-octene.

[0037] In one embodiment of the present invention, the solvent used to dissolve the organic boron salt in the olefin polymerization reaction includes at least one of benzene, toluene, xylene, chlorobenzene, aromatic derivatives, pentane, hexane, heptane, decane, cyclohexane, methylcyclohexane and branched alkanes. By using the borate of the present invention as a co-catalyst, the anions and cations generated by the reaction are dissolved in the hydrocarbon solvent for the active center of olefin polymerization, forming a stable liquid phase catalytic system, rather than the emulsion heterogeneous catalytic system formed by the traditional borate, which is conducive to improving the efficiency of the catalyst.

[0038] In an embodiment of the present invention, the olefin polymerization catalyst system constructed by the organic boron salt of the present invention is an olefin solution polymerization reaction system.

[0039] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0040] Example 1 Synthesis of Fluorophenyl Borate B1

[0041] Under nitrogen atmosphere, 1,4-dibromo-tetrafluorobenzene (7.70 g, 25.0 mmol) was added to a 250 mL three-necked flask (equipped with a magnet and a low-temperature thermometer), and 80 mL of ether was added. After stirring to dissolve, the mixture was placed in a low-temperature cooling bath and cooled to -78 o C. Slowly add 10mL with a syringe n BuLi hexane solution (2.5M), control the reaction temperature not higher than -70 o C, after the addition is complete, continue stirring for 0.5h. Slowly add SiMe 3 Cl (2.72 g, 25.0 mmol), and then slowly warmed to room temperature to generate 1,2,5,6-tetrafluoro-4-trimethylsilyl-bromobenzene and LiCl precipitation.

[0042] The reaction solution was cooled to -78 o C, slowly add 10mL with a syringe n BuLi hexane solution (2.5M) was reacted for 0.5 h to generate 1,2,5,6-tetrafluoro-4-trimethylsilyl-phenyllithium. 6.3 mL of BCl was added by syringe. 3 The hexane solution (1.0 M) was slowly heated to room temperature to generate Li[B(C 6 F 4 -SiMe 3 - p ) 4 ] and white LiCl precipitate. LiCl was removed by filtration, the ether solvent was vacuum-dried, and the mixture was heated at 90 o C was dried under vacuum for 5 h to obtain a pale yellow waxy solid Li[B(C 6 F 4-SiMe 3 - p ) 4 ](5.19g, 92% yield).

[0043] Li[B(C 6 F 4 -SiMe 3 - p ) 4 ] was dissolved in 50% toluene, and an equal molar amount of Ph 3 CCl (1.60 g, 5.75 mmol) solid, the solution color quickly turned yellow, after 2 h of reaction, the solution color turned yellow-brown. Filter the toluene solution with diatomaceous earth to remove the generated LiCl, and wash with 20 mL of dry toluene. Vacuum dry the toluene and heat at 60 o C, vacuum dried for 24 h to obtain a yellow-green solid powder [Ph 3 C][B(C 6 F 4 -SiMe 3 - p ) 4 ], the overall yield was 87.4% (based on BCl 3 ).

[0044] 1 H NMR: 7.97 (m, 6 H); 8.12 (m, 3 H); 8.54 (m, 6 H); 0.21 (s, 36 H). Elemental analysis (for C 55 H 51 BF 16 Si 4 ): C, 57.66%; H, 4.68%.

[0045] Example 2 Synthesis of Fluorophenylboronic Acid B2

[0046] According to the method of Example 1, Li[B(C 6 F 4 -SiMe 3 - p ) 4 ]. Weigh 4.51 g Li[B(C 6 F 4 -SiMe 3 - p ) 4 ] (5.0 mmol) was dissolved in 50 ether, and an equal mole of PhNHMe was added under stirring at room temperature. 2Cl (0.79 g, 5.0 mmol) solid was added, and then 10 mL of distilled water was added and stirred for 2 h. The ether solution was separated by a separatory funnel, and the aqueous solution was extracted with 20 mL of ether. The ether solution was combined and dried over anhydrous sodium carbonate. The ether solvent was removed in vacuo to obtain a light yellow solid, which was then washed alternately with distilled water and hexane three times, and then 60 o After drying under vacuum for 24 h, a white solid [PhNHMe 2 ][B(C 6 F 4 -SiMe 3 - p ) 4 ] (3.66 g, 3.6 mmol), yield 72%. 1 H NMR: 7.47 (m, 2 H); 6.92 (m, 1 H); 6.34 (m, 2 H); 3.23 (s, 6 H), 0.22 (s, 36 H). Elemental analysis (for C 44 H 48 BF 16 NSi 4 ): C, 51.86%; H, 4.65%.

[0047] Example 3 Synthesis of Fluorophenylboronic Acid B3

[0048] According to the method of Example 1, Li[B(C 6 F 4 -SiMe 3 - p ) 4 ]. Weigh 4.51 g Li[B(C 6 F 4 -SiMe 3 - p ) 4 ] (5.0 mmol) was dissolved in 50% toluene, and an equal mole of (C 18 H 37 ) 2 NHMeCl (2.86 g, 5.0 mmol) solid was added, followed by 10 mL of distilled water and stirred for 2 h. The toluene solution was separated by a separatory funnel and dried over anhydrous sodium carbonate. The toluene solvent was removed in vacuo and the mixture was heated to 120 °C. o C was dried under vacuum for 12 h to obtain a light yellow oil [(C 18 H 37 ) 2 NH][B(C 6 F 4 -SiMe 3 -p ) 4 ](4.66 g, 3.25 mmol), yield 65%. 1 H NMR: 2.96 (br, 2H), 2.82 (br, 2H), 2.57 (br, 3H), 2.52 (br, 4H), 1.16 (m, 60H), 0.80 (m, 6H), 0.27 (s, 36H). Elemental analysis (for C 73 H 114 BF 16 NSi 4 ): C, 60.99%; H, 8.23%.

[0049] Example 4 Synthesis of Fluorophenylboronic Acid B4

[0050] Under nitrogen atmosphere, 1,4-dibromo-tetrafluorobenzene (7.70 g, 25.0 mmol) was added to a 250 mL three-necked flask (equipped with a magnet and a low-temperature thermometer), and 80 mL of ether was added. After stirring to dissolve, the mixture was placed in a low-temperature cooling bath and cooled to -78 o C. Slowly add 10mL with a syringe n BuLi hexane solution (2.5M), control the reaction temperature not higher than -70 o C, after the addition is complete, continue stirring for 0.5h. Slowly add SiEt 3 Cl (3.77 g, 25.0 mmol), and then slowly warmed to room temperature to generate 1,2,5,6-tetrafluoro-4-triethylsilyl-bromobenzene and LiCl precipitate. The reaction solution was cooled to -78 o C, slowly add 10mL with a syringe n BuLi hexane solution (2.5 M) was reacted for 0.5 h to generate 1,2,5,6-tetrafluoro-4-triethylsilyl-phenyllithium. 6.3 mL of BCl was added by syringe. 3 The hexane solution (1.0 M) was slowly heated to room temperature to generate Li[B(C 6 F 4 -SiEt 3 - p ) 4 ] and white LiCl precipitate. LiCl was removed by filtration, the ether solvent was vacuum-dried, and the mixture was heated at 90 o C was dried under vacuum for 5 h to obtain a pale yellow waxy solid Li[B(C 6 F 4 -SiEt 3 - p ) 4](6.02g, 90%yield). Put Li[B(C 6 F 4 -SiEt 3 - p ) 4 ] was dissolved in 50% toluene, and an equal molar amount of Ph 3 CCl (1.57 g, 5.63 mmol) solid, the solution color quickly turned yellow, after 2 h of reaction, the solution color turned yellow-brown. Filter the toluene solution with diatomaceous earth to remove the generated LiCl, and wash with 20 mL of dry toluene. Vacuum dry the toluene and heat at 60 o C, vacuum dried for 24 h to obtain a yellow solid powder [Ph 3 C][B(C 6 F 4 -SiEt 3 - p ) 4 ], the overall yield was 83.4% (based on BCl 3 ). 1 H NMR: 7.92 (m, 6 H); 8.17 (m, 3 H); 8.49 (m, 6 H); 0.32 (m, 24 H), 0.83 (m, 36 H). Elemental analysis (for C 67 H 75 BF 16 Si 4 ): C, 61.06%; H, 5.84%.

[0051] Example 5 Synthesis of Fluorophenylboronic Acid B5

[0052] According to the method of Example 4, Li[B(C 6 F 4 -SiEt 3 - p ) 4 ]. Weigh 5.36 g Li[B(C 6 F 4 -SiEt 3 - p ) 4 ] (5.0 mmol) was dissolved in 50 ether, and an equal mole of PhNHMe was added under stirring at room temperature. 2Cl (0.79 g, 5.0 mmol) solid was added, and then 10 mL of distilled water was added and stirred for 2 h. The ether solution was separated by a separatory funnel, and the aqueous solution was extracted with 20 mL of ether. The ether solution was combined and dried over anhydrous sodium carbonate. The ether solvent was removed in vacuo to obtain a light yellow solid, which was then washed alternately with distilled water and hexane three times, and then 60 o After drying under vacuum for 24 h, a white solid [PhNHMe 2 ][B(C 6 F 4 -SiEt 3 - p ) 4 ] (3.26 g, 2.75 mmol), yield 55%. 1 H NMR: 7.46 (m, 2 H); 6.88 (m, 1 H); 6.35 (m, 2 H); 3.27 (s, 6H), 0.33 (m, 24 H), 0.84 (m, 36 H). Elemental analysis (for C 56 H 72 BF 16 NSi 4 ): C, 56.56%; H, 6.23%.

[0053] Example 6 Synthesis of Fluorophenylboronic Acid B6

[0054] According to the method of Example 4, Li[B(C 6 F 4 -SiEt 3 - p ) 4 ]. Weigh 5.36 g Li[B(C 6 F 4 -SiEt 3 - p ) 4 ] (5.0 mmol) was dissolved in 50% toluene, and an equal mole of (C 18 H 37 ) 2 NHMeCl (2.86 g, 5.0 mmol) solid was added, followed by 10 mL of distilled water and stirred for 2 h. The toluene solution was separated by a separatory funnel and dried over anhydrous sodium carbonate. The toluene solvent was removed in vacuo and the mixture was heated to 120 °C. o C was dried under vacuum for 12 h to obtain a light yellow oil [(C 18 H 37 ) 2 NH][B(C 6 F 4 -SiEt3 - p ) 4 ](4.88 g, 3.05 mmol), yield 61%. 1 H NMR: 2.93 (br, 2H), 2.83 (br, 2H), 2.56 (br, 3H), 1.56 (br, 4H), 1.17 (m, 60H), 0.88 (m, 42H), 0.80 (m, 24H). Elemental analysis (for C 85 H 138 BF 16 NSi 4 ): C, 63.44%; H, 8.54%.

[0055] Example 7 Synthesis of Fluorophenylboronic Acid B7

[0056] Under nitrogen atmosphere, 1,4-dibromo-tetrafluorobenzene (7.70 g, 25.0 mmol) was added to a 250 mL three-necked flask (equipped with a magnet and a low-temperature thermometer), and 80 mL of ether was added. After stirring to dissolve, the mixture was placed in a low-temperature cooling bath and cooled to -78 o C. Slowly add 10mL with a syringe n BuLi hexane solution (2.5M), control the reaction temperature not higher than -70 o C, after the addition is complete, continue stirring for 0.5h. Slowly add Si n Bu 3 Cl (5.87 g, 25.0 mmol), and then slowly warmed to room temperature to generate 1,2,5,6-tetrafluoro-4-tributylsilyl-bromobenzene and LiCl precipitate. The reaction solution was cooled to -78 o C, slowly add 10mL with a syringe n BuLi hexane solution (2.5 M) was reacted for 0.5 h to generate 1,2,5,6-tetrafluoro-4-tributylsilyl-phenyllithium. 6.3 mL of BCl was added by syringe. 3 The hexane solution (1.0 M) was slowly heated to room temperature to generate Li[B(C 6 F 4 -Si n Bu 3 - p ) 4 ] and white LiCl precipitate. LiCl was removed by filtration, the ether solvent was vacuum-dried, and the mixture was heated at 90 o C was dried under vacuum for 5 h to obtain a light yellow viscous liquid Li[B(C 6 F 4 -Si n Bu3 - p ) 4 ](8.18g, 93%yield). Put Li[B(C 6 F 4 -Si n Bu 3 - p ) 4 ] was dissolved in 50% toluene, and an equal molar amount of Ph 3 CCl (1.57 g, 5.63 mmol) solid, the solution color quickly turned yellow, after 2 h of reaction, the toluene solution was filtered through diatomaceous earth to remove the generated LiCl, and washed with 20 mL of dry toluene. Toluene was vacuum-dried and heated at 60 o C, and vacuum dried for 24 h to obtain a yellow-brown product [Ph 3 C][B(C 6 F 4 -Si n Bu 3 - p ) 4 ], the overall yield was 83.4% (based on BCl 3 ). 1 H NMR: 7.94 (m, 6 H); 8.13 (m, 3 H); 8.51 (m, 6 H); 1.32 (m, 48 H), 0.81 (m, 36 H), 0.54 (m, 32 H). Elemental analysis (for C 91 H 123 BF 16 Si 4 ): C, 66.76%; H, 7.67%.

[0057] Example 8 Synthesis of Fluorophenylboronic Acid B8

[0058] According to the method of Example 7, Li[B(C 6 F 4 -Si n Bu 3 - p ) 4 ]. Weigh 7.04 g Li[B(C 6 F 4 -Si n Bu 3 - p ) 4 ] (5.0 mmol) was dissolved in 50 ether, and an equal mole of PhNHMe was added under stirring at room temperature. 2Cl (0.79 g, 5.0 mmol) solid, then add 10 mL of distilled water and stir for 2 h. Separate the ether solution with a separatory funnel, extract the aqueous solution with 20 mL of ether, combine the ether solution, and dry it over anhydrous sodium carbonate. Remove the ether solvent in vacuo to obtain a light yellow viscous solid, which is crystallized in a mixed solvent of n-hexane and ether to obtain a white solid [PhNHMe 2 ][B(C 6 F 4 -Si n Bu 3 - p ) 4 ] (2.67 g, 1.75 mmol), yield 35%. 1 H NMR: 7.45 (m, 2 H); 6.88 (m, 1 H); 6.33 (m, 2 H); 3.25 (s, 6H), 1.33 (m, 48 H), 0.82 (m, 36 H), 0.51 (m, 32 H). Elemental analysis (for C 80 H 120 BF 16 NSi 4 ): C, 63.15%; H, 7.97%.

[0059] Example 9 Synthesis of Fluorophenylboronic Acid B9

[0060] According to the method of Example 7, Li[B(C 6 F 4 -Si n Bu 3 - p ) 4 ]. Weigh 7.04 g Li[B(C 6 F 4 -Si n Bu 3 - p ) 4 ] (5.0 mmol) was dissolved in 50% toluene, and an equal mole of (C 18 H 37 ) 2 NHMeCl (2.86 g, 5.0 mmol) solid was added, followed by 10 mL of distilled water and stirred for 2 h. The toluene solution was separated by a separatory funnel and dried over anhydrous sodium carbonate. The toluene solvent was removed in vacuo and the mixture was heated to 120 °C. o C was dried under vacuum for 12 h to obtain a light yellow oil [(C 18 H 37 ) 2 NH][B(C 6F 4 -Si n Bu 3 - p ) 4 ](6.88 g, 3.55 mmol), yield 71%. 1 H NMR: 2.92 (br, 2H), 2.83 (br, 2H), 2.56 (br, 3H), 1.58 (br, 4H), 1.17 (m, 110H), 0.79 (m, 64H). Elemental analysis (for C 109 H 186 BF 16 NSi 4 ): C, 67.49%; H, 9.59%.

[0061] Example 10 Synthesis of Fluorophenyl Borate B10

[0062] Under nitrogen atmosphere, 1,4-dibromo-tetrafluorobenzene (7.70 g, 25.0 mmol) was added to a 250 mL three-necked flask (equipped with a magnet and a low-temperature thermometer), and 80 mL of ether was added. After stirring to dissolve, the mixture was placed in a low-temperature cooling bath and cooled to -78 o C. Slowly add 10mL with a syringe n BuLi hexane solution (2.5M), control the reaction temperature not higher than -70 o C, after the addition was complete, continue stirring for 0.5 h. Slowly add Si(C 7 H 15 ) 3 Cl (9.03 g, 25.0 mmol), and then slowly warmed to room temperature to generate 1,2,5,6-tetrafluoro-4-trimethylsilyl-bromobenzene and LiCl precipitate. The reaction solution was cooled to -78 o C, slowly add 10mL with a syringe n BuLi hexane solution (2.5 M) was reacted for 0.5 h to generate 1,2,5,6-tetrafluoro-4-trimethylsilyl-phenyllithium. 6.3 mL of BCl was added by syringe. 3 The hexane solution (1.0 M) was slowly heated to room temperature to generate Li[B(C 6 F 4 -Si(C 7 H 15 ) 3 - p ) 4 ] and white LiCl precipitate. LiCl was removed by filtration, the ether solvent was vacuum-dried, and the mixture was heated at 90 oC was dried under vacuum for 5 h to obtain a light yellow viscous liquid Li[B(C 6 F 4 -Si(C 7 H 15 ) 3 - p ) 4 ](10.64 g, 89% yield). 6 F 4 -Si(C 7 H 15 ) 3 - p ) 4 ] was dissolved in 50% toluene, and an equal molar amount of Ph 3 CCl (1.60 g, 5.75 mmol) solid, the solution color quickly turned yellow, after 2 h of reaction, the solution color turned yellow-brown. Filter the toluene solution with diatomaceous earth to remove the generated LiCl, and wash with 20 mL of dry toluene. Vacuum dry the toluene and heat at 60 o C, vacuum dried for 24 h to obtain [Ph 3 C][B(C 6 F 4 -Si(C 7 H 15 ) 3 - p ) 4 ], the overall yield was 78.4% (based on BCl 3 ). 1 H NMR: 7.85 (m, 6 H); 8.17 (m, 3 H); 8.43 (m, 6 H); 1.41 (m, 120 H), 0.79 (m, 36 H), 0.47 (m, 32 H). Elemental analysis (for C 127 H 195 BF 16 Si 4 ): C, 70.58%; H, 9.27%.

[0063] Embodiment 11 Synthesis of Fluorophenyl Borate B11

[0064] According to the method of Example 10, Li[B(C 6 F 4 -Si(C 7 H 15 ) 3 - p ) 4 ]. Weigh 9.56 g Li[B(C6 F 4 -Si(C 7 H 15 ) 3 - p ) 4 ] (5.0 mmol) was dissolved in 50% toluene, and an equal mole of (C 18 H 37 ) 2 NHMeCl (2.86 g, 5.0 mmol) solid was added, followed by 10 mL of distilled water and stirred for 2 h. The toluene solution was separated by a separatory funnel and dried over anhydrous sodium carbonate. The toluene solvent was removed in vacuo and the mixture was heated to 120 °C. o C was dried under vacuum for 12 h to obtain a light yellow oil [(C 18 H 37 ) 2 NH][B(C 6 F 4 -Si(C 7 H 15 ) 3 - p ) 4 ](9.16 g, 3.75 mmol), yield 75%. 1 H NMR: 2.93 (br, 2H), 2.82 (br, 2H), 2.56 (br, 3H), 1.59 (br, 4H), 1.18 (m, 182H), 0.76 (m, 64H). Elemental analysis (for C 145 H 258 BF 16 NSi 4 ): C, 71.29%; H, 10.23% Example 12 Synthesis of Fluorophenylborate B12

[0065] Under nitrogen atmosphere, add 4-tert-butyl-2,3,5,6-tetrafluorobromobenzene (7.13 g, 25.0 mmol) into a 250 mL three-necked flask (equipped with a magnet and a low-temperature thermometer), add 80 mL of ether, stir to dissolve, and place in a low-temperature cooling bath to cool to -78 o C. Slowly add 10mL with a syringe n BuLi hexane solution (2.5M), control the reaction temperature not higher than -70 o C, after the addition was complete, stirring was continued for 0.5 h to generate 4-tert-butyl-2,3,5,6-tetrafluorophenyl lithium, and 6.3 mL of BCl was added with a syringe. 3 The hexane solution (1.0 M) was slowly heated to room temperature to generate Li[B(C6 F 4 - t Bu- p ) 4 ] and white LiCl precipitate. LiCl was removed by filtration, the ether solvent was vacuum-dried, and the mixture was heated at 90 o C was dried under vacuum for 5 h to obtain a pale yellow waxy solid Li[B(C 6 F 4 - t Bu- p ) 4 ](4.45g, 85%yield). Put Li[B(C 6 F 4 - t Bu- p ) 4 ] was dissolved in 50% toluene, and an equal molar amount of Ph 3 CCl (1.48 g, 5.31 mmol) solid, the solution color quickly turned yellow, after 2 h of reaction, the solution color turned yellow-brown. Filter the toluene solution with diatomaceous earth to remove the generated LiCl, and wash with 20 mL of dry toluene. Vacuum dry the toluene and heat at 60 o C, and vacuum dried for 24 h to obtain a yellow solid [Ph 3 C][B(C 6 F 4 - t Bu- p ) 4 ], the overall yield was 72.3% (based on BCl 3 ). 1 H NMR: 7.92 (m, 6 H); 8.17 (m, 3 H); 8.54 (m, 6 H); 1.12 (m, 36 H). Elemental analysis (for C 59 H 51 BF 16 ): C, 66.02%; H, 4.59%.

[0066] Example 13 Synthesis of Fluorophenyl Borate B13

[0067] According to the method of Example 13, Li[B(C 6 F 4 - t Bu- p ) 4 ]. Weigh 4.19 g Li[B(C 6 F 4 - t Bu-p ) 4 ] (5.0 mmol) was dissolved in 50 ether, and an equal mole of PhNHMe was added under stirring at room temperature. 2 Cl (0.79 g, 5.0 mmol) solid, then add 10 mL of distilled water and stir for 2 h. Separate the ether solution with a separatory funnel, extract the aqueous solution with 20 mL of ether, combine the ether solutions, and dry with anhydrous sodium carbonate. Remove the ether solvent in vacuo to obtain a light yellow solid, which is washed alternately with distilled water and n-hexane three times to obtain a white solid [PhNHMe 2 ][B(C 6 F 4 - t Bu- p ) 4 ] (3.10 g, 3.25 mmol), yield 65%. 1 H NMR: 7.51 (m, 2 H); 6.85 (m, 1 H); 6.33 (m, 2 H); 3.25 (s, 6 H), 1.14 (m, 36 H). Elemental analysis (for C 48 H 48 BF 16 ): C, 60.32%; H, 4.99%.

[0068] Embodiment 14 Synthesis of Fluorophenyl Borate B14

[0069] According to the method of Example 13, Li[B(C 6 F 4 - t Bu- p ) 4 ]. Weigh 4.19 g Li[B(C 6 F 4 - t Bu- p ) 4 ] (5.0 mmol) was dissolved in 50% toluene, and an equal mole of (C 18 H 37 ) 2 NHMeCl (2.86 g, 5.0 mmol) solid was added, followed by 10 mL of distilled water and stirred for 2 h. The toluene solution was separated by a separatory funnel and dried over anhydrous sodium carbonate. The toluene solvent was removed in vacuo and the mixture was heated to 120 °C. o C was dried under vacuum for 12 h to obtain a light yellow oil [(C 18 H 37 ) 2 NH][B(C 6 F 4- t Bu- p ) 4 ](5.82 g, 4.25 mmol), yield 85%. 1 H NMR: 2.94 (br, 2H), 2.82 (br, 2H), 2.57 (br, 3H), 1.58 (br, 4H), 1.16 (m, 60H), 0.80 (m, 6H), 1.12 (m, 36H). Elemental analysis (for C 77 H 114 BF 16 N): C, 67.43%; H, 8.49%.

[0070] Test Example 1 Olefin polymerization experiments In order to evaluate the performance of the organic boron olefin cocatalyst synthesized by the present invention, the experimental example selected ethylene-octene copolymerization reaction for experiment. The structure of the selected metallocene main catalyst (the synthesis method is recorded in the invention patent CN 115894573 B) is:

[0071] The organoboron olefin cocatalyst in the prior art (the synthesis method is recorded in the following patents and documents: US006169208B1; WO 97 / 35893[P]; H. Li, DC Neckers, Can. J. Chem., 2003,81, 758) compared with the present invention is:

[0072]

[0073] Instruments and equipment: high temperature and high pressure intermittent reactor, hot press, electronic density meter, melt flow rate meter, high temperature gel permeation chromatograph (GPC).

[0074] The experimental conditions for ethylene-octene copolymerization are as follows: In the CGC-Ti catalytic ethylene-octene polymerization experiment, the reaction temperature was 140°C, the ethylene pressure was 2MPa, the octene concentration was 1.5M, the catalyst dosage was 3.0umol, the reaction time was 10min, the total solvent volume was 30mL, the concentration ratio was: B / Ti=1.1, Al / Ti=150, and the CGC-Ti metallocene catalyst, organic boron olefin cocatalyst, and triisobutylaluminum were all toluene solutions.

[0075] The experimental steps of ethylene-octene polymerization are as follows: The autoclave was vacuum dried at 150°C for 1 h, and then the reaction system was replaced with ethylene three times. When the temperature of the autoclave dropped below 60°C, 16.4 mL of n-hexane, 7.1 mL of octene, and 4.5 mL of triisobutylaluminum were added in sequence. After stirring for 1 minute (stirring rate 1000 rpm), the autoclave temperature was heated to 140 o C, add 1mL of toluene solution of metallocene catalyst CGC-Ti to the catalyst feeder, press it into the reactor with ethylene, then add toluene solution of organic boron olefin cocatalyst to the system in the same way, open the ethylene flow valve, keep the system ethylene pressure at 2MPa, and react for 10 minutes. After the reaction is completed, add acidified ethanol to extract. The polymer solution is precipitated with acidified ethanol, dried and pressed into sheets, and density, melt index determination, GPC and other analytical tests are performed. The results are shown in Tables 1 to 3. Table 1 shows the metallocene CGC-Ti as the main catalyst, substituted organic boron salt [Ph 3 C][B(C 6 F 4 -R- p ) 4 ](B1: R=SiMe 3 , B4: R=SiEt 3 , B7: R=Si n Bu 3 ,B10:R=Si(C 7 H 15 ) 3 , B12: R= t Bu) and [Ph 3 C][B(C 6 F 5 ) 4 ](B15, commercial co-catalyst) is the experimental results of ethylene-octene copolymerization with olefin polymerization co-catalyst.

[0076] Table 1 CGC-Ti / [Ph 3 C][B(C 6 F 4 -R- p ) 4 Catalytic properties data of

[0077] Table 2 shows the metallocene CGC-Ti as the main catalyst, substituted organic boron salt [PhNHMe 2 ][B(C 6 F 4 -R- p ) 4 ](B2: R=SiMe 3 , B5: R=SiEt 3, B8: R=Si n Bu 3 , B13: R= t Bu) and [PhNHMe 2 ][B(C 6 F 5 ) 4 ](B16, commercial co-catalyst) is the experimental results of ethylene-octene copolymerization with olefin polymerization co-catalyst.

[0078] Table 2 CGC-Ti / [PhNHMe 2 ][B(C 6 F 4 -R- p ) 4 Catalytic properties data of

[0079] Table 3 shows that metallocene CGC-Ti as the main catalyst, substituted organic boron salt [(C 18 H 37 ) 2 NHMe][B(C 6 F 4 -R- p ) 4 ](B3:R=SiMe 3 , B6: R=SiEt 3 , B9: R=Si n Bu 3 , B14: R= t Bu) and [(C 18 H 37 ) 2 NHMe][B(C 6 F 5 ) 4 ](B17, commercial co-catalyst) is the experimental results of ethylene-octene copolymerization with olefin polymerization co-catalyst.

[0080] Table 3 CGC-Ti / [(C 18 H 37 ) 2 NHMe][B(C 6 F 4 -R- p ) 4 Catalytic properties data of

[0081] It can be seen from the polymerization data in Table 1, Table 2 and Table 3 that under the same boron salt cation conditions, the polymerization activity of the perfluorotetraphenylborate substituted with a large steric hindrance group in the para position of the present invention is significantly higher than that of the commercial perfluorotetraphenylborate, and the polymerization activity increases with the increase of the steric hindrance of the substituent. This may be mainly due to the following two reasons: (1) After the fluorophenylboronic acid anion is modified with a large steric group, the polarity of the anion can be effectively reduced, thereby increasing the solubility of the organic boron olefin polymerization co-catalyst in non-polar solvents, making the activation reaction of the metallocene main catalyst more uniform, and effectively increasing the concentration of the olefin polymerization active center; (2) The sterically substituted perfluorotetraphenylborate reacts with the metallocene cocatalyst to form anion-cation pairs that are active olefin polymerization centers and have better solubility in hydrocarbon solvents, making it easier to achieve homogeneous solution polymerization. (3) The perfluorotetraphenylborate with large steric hindrance and the metallocene cocatalyst react to form anion-cation pair active olefin polymerization center. Due to the spatial effect of the substituent, the interaction between the anion-cation pair can be weakened, making the ion pair active center looser, which is conducive to the coordination and insertion reaction of the olefin.

[0082] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An organic boron salt olefin polymerization cocatalyst, characterized in that: Having the structure shown in Formula I: Formula I; Among them, Ct + It is a cation that can cause alkyl elimination in a metal alkyl chain, R1 is independently selected from a carbon or silicon atom; R2, R3, and R4 are independently selected from hydrogen, an alkyl group, or a phenyl group.

2. The organic boron salt olefin polymerization cocatalyst according to claim 1, characterized in that: Ct + Selected from triarylmethyl carbocations or protonated organic amine ions.

3. The organic boron salt olefin polymerization cocatalyst according to claim 1, characterized in that: The triarylmethyl carbocation is selected from triphenylmethyl carbocation or tri(alkylated phenyl)methyl carbocation derivatives; The organic amines include primary amines, secondary amines or tertiary amines and their derivatives.

4. The organic boron salt olefin polymerization cocatalyst according to claim 1, characterized in that: R2, R3, and R4 are independently selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, cyclopentyl, cyclohexyl, or phenyl.

5. The method for preparing the organic boron salt olefin polymerization cocatalyst according to any one of claims 1 to 4, characterized in that: The steps include: 1) 1,4-dibromotetrafluorobenzene reacts with alkyl lithium or Grignard reagent to generate corresponding p-bromotetrafluorophenyl lithium or p-bromotetrafluorophenyl Grignard reagent; then reacts with halogen silane or halogenated hydrocarbon in situ to generate p-substituted tetrafluorobromobenzene derivative; 2) the para-substituted tetrafluorobromobenzene derivative is reacted with an alkyl lithium or a Grignard reagent to generate a corresponding phenyl metal reagent, which is then reacted in situ with a boron halide to generate an organic lithium borate or an organic magnesium borate with a large para-position steric substitution; 3) The above-mentioned organic borate lithium or organic borate magnesium with bulky steric substituted para position reacts with protonated organic amine or triaryl chloromethane to obtain an organic boron salt olefin polymerization cocatalyst.

6. The preparation method according to claim 5, characterized in that: In step 1), the molar ratio of 1,4-dibromotetrafluorobenzene, p-bromotetrafluorophenyl lithium or p-bromotetrafluorophenyl Grignard reagent, and halogenated silane or halogenated hydrocarbon is 1:0.5-1.5:0.5-1.5; In step 2), the molar ratio of the para-substituted tetrafluorobromobenzene derivative, the alkyl lithium or Grignard reagent, and the boron halide is 1:0.5-1.5:0.1-0.35; In step 3), the molar ratio of the para-position sterically hindered organic lithium borate or organic magnesium borate to the protonated organic amine or triaryl chloromethane is 1:0.5-2.

0.

7. Use of the organic boron salt olefin polymerization cocatalyst according to any one of claims 1 to 4 in olefin polymerization reactions.

8. The use according to claim 7, characterized in that: The main catalyst used in olefin polymerization reaction and co-acting with the above-mentioned co-catalyst includes a metal organic complex precursor that can form a cationic metal polymerization active center; Preferably, the main catalyst used for olefin polymerization reaction and co-acting with the above-mentioned co-catalyst is a metallocene compound or a non-metallocene compound for olefin polymerization.

9. The use according to claim 7, characterized in that: The raw monomers for olefin polymerization include linear, branched or cyclic olefins or diolefins; Preferably, the reaction raw material monomers for olefin polymerization reaction include at least one of ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, norbornene, norbornadiene, vinyl norbornene, ethylidene norbornene monomer, 1,5-hexadiene, 1,6-heptadiene, and 1,7-octadiene.

10. The use according to claim 7, characterized in that: The solvent used for dissolving the organic boron salt in olefin polymerization reaction includes at least one of benzene, toluene, xylene, chlorobenzene, aromatic derivatives, pentane, hexane, heptane, decane, cyclohexane, methylcyclohexane and branched alkane.

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