Preparation method and application of borate compound

Abstract

The invention belongs to the technical field of preparation of borate compounds, and discloses a preparation method and application of a borate compound, the preparation method comprises the following steps: 1) mixing a halogenated derivative of benzene with a solvent, dropwise adding an n-butyllithium solution at-60 DEG C to-100 DEG C under the protection of nitrogen, reacting for 2-24 hours, adding a boron trichloride solution, and continuously reacting for 1-36 hours; 2) heating the reaction mixture obtained in the step 1) to normal temperature, then reducing pressure and heating to remove the solvent to obtain a crude product, adding dichloromethane and amines or amine hydrochloride into the crude product, and stirring to react for 0.5-4 hours; and 3) filtering the product obtained in the step 2), adding hexane into the filtrate, stirring, standing for 0.5-5 hours, adding hexane again, stirring, standing for 12-48 hours, filtering, collecting crystals, and drying to obtain the borate compound. The preparation method is simple and easy to implement, raw materials are cheap, and the yield of the borate compound is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of borate compounds, and in particular, relates to a preparation method and application of a borate compound. Background Art

[0002] Since the early 1980s, when Professor Kaminsky formally proposed the metallocene catalyst system, a typical catalyst system is generally composed of two major parts, namely, various metallocene compounds located in the IVB group of the periodic table of elements, such as zirconium, hafnium, titanium, etc., as the main catalyst, and aluminoxane (MAO) as the cocatalyst. In the subsequent technological development, most of the patent documents have made a lot of improvements on the type and structure of the main catalyst metallocene compound, generally using aluminoxane, a hydrolysis product of alkyl aluminum, as a cocatalyst, with methylaluminoxane in the majority. Only a small amount of patent documents report the use of ionizing ion activators or cationic activators as cocatalysts, such as boron compounds.

[0003] Patent document CN108752526A discloses a catalytic system for preparing ethylene and / or α-olefin and cycloolefin copolymers, specifically a toluene solution of a metallocene compound, an organic boron compound and an alkyl aluminum.

[0004] Patent document CN104684919A discloses a method for preparing ammonium borate salt, specifically using an amine salt to react with potassium tetrakispentafluorobenzeneborate and using it for metallocene solution polymerization.

[0005] Borate compounds are widely used as co-catalysts in solution polymerization systems because they have better thermal stability than methylaluminoxane and are used in a smaller stoichiometric ratio relative to metal complexes than methylaluminoxane. Existing borate compound preparation methods have problems such as using unconventional chemical raw materials as starting materials, high prices, lengthy synthesis routes, and low conversion rates, which are not conducive to their industrial development. Summary of the invention

[0006] In view of the above problems existing in the prior art, the purpose of the present invention is to provide a method for preparing a borate compound and its application, the preparation process is simple and easy, the raw materials used are cheap, and the yield of the obtained borate compound is high.

[0007] A first aspect of the present invention provides a method for preparing a borate compound, the preparation method comprising the following steps:

[0008] 1) Mix the halogenated derivative of benzene and the solvent, add n-butyl lithium solution dropwise at -60°C to -100°C under nitrogen protection and react for 2 to 24 hours, then add boron trichloride solution and continue to react for 1 to 36 hours;

[0009] 2) heating the reaction mixture obtained in step 1) to room temperature, then removing the solvent by heating under reduced pressure to obtain a crude product, adding dichloromethane and amines or amine hydrochlorides to the crude product, and stirring the reaction for 0.5 to 4 hours;

[0010] 3) filtering the product obtained in step 2), adding hexane to the filtrate and stirring, then standing for 0.5 to 5 hours, adding hexane again and stirring, standing for 12 to 48 hours, then filtering and collecting the crystals, and drying to obtain the borate compound.

[0011] The second aspect of the present invention provides the use of the borate compound prepared by the above preparation method as a co-catalyst for a metallocene catalyst.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. The preparation process of the present invention is simple and easy. By reasonably setting the reaction steps and the post-reaction treatment process, the reaction molar yield of the borate compound can reach more than 90%. The starting materials and solvents are cheap chemical raw materials, and the reaction process can be synthesized in only one reactor, reducing the loss of reactants caused by transfer. The process route is suitable for industrial production.

[0014] 2. In the process of preparing the borate compound of the present invention, water and oxygen are isolated, no water phase reaction is used, and no catalyst poisons of olefin polymerization reaction are contained. The borate compound can be used as a boron co-catalyst in catalytic reactions with high requirements for water and oxygen in raw materials, such as metallocene-catalyzed olefin polymerization process, and has good economic value.

[0015] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0017] According to a first aspect of the present invention, the present invention provides a method for preparing a borate compound, the preparation method comprising the following steps:

[0018] 1) Mix the halogenated derivative of benzene and the solvent, add n-butyl lithium solution dropwise at -60°C to -100°C under nitrogen protection and react for 2 to 24 hours, then add boron trichloride solution and continue to react for 1 to 36 hours;

[0019] 2) heating the reaction mixture obtained in step 1) to room temperature, then removing the solvent by heating under reduced pressure to obtain a crude product, adding dichloromethane and amines or amine hydrochlorides to the crude product, and stirring the reaction for 0.5 to 4 hours;

[0020] 3) filtering the product obtained in step 2), adding hexane to the filtrate and stirring, then standing for 0.5 to 5 hours, adding hexane again and stirring, standing for 12 to 48 hours, then filtering and collecting the crystals, and drying to obtain the borate compound.

[0021] In the present invention, the structure of the halogenated derivative of benzene can be shown as formula (1):

[0022]

[0023] In formula (1), R1 to R6 are each selected from fluorine, chlorine, bromine and iodine.

[0024] According to the present invention, the solvent in step 1) is an alkane and / or ether solvent, specifically, the alkane and / or ether solvent can be selected from at least one of n-octane, n-heptane, n-hexane, isohexane, cyclohexane, methylcyclohexane, petroleum ether, ethyl ether and dibutyl ether.

[0025] In the present invention, the amount of the solvent used in step 1) is 2 to 5 L, preferably 2 to 2.5 L, and more preferably 2 to 2.25 L per mole of the halogenated derivative of benzene; the amount of n-butyl lithium used in the n-butyl lithium solution is 1 mol; the amount of boron trichloride used in the boron trichloride solution is 0.15 to 0.35 mol, preferably 0.2 to 0.25 mol;

[0026] Preferably, the solvents of the n-butyl lithium solution and the boron trichloride solution are the same as the solvent in step 1). The molar concentrations of the n-butyl lithium solution and the boron trichloride solution can be selected as required, for example, 0.5 to 2M.

[0027] In step 1), the reaction temperature is always kept the same, and the reaction temperature range is preferably -70 to -90°C, more preferably -75 to -85°C. Since the addition of n-butyl lithium solution is relatively slow, the time for adding n-butyl lithium solution and reacting includes two stages: the first stage is the time for reacting while adding n-butyl lithium solution, and the second stage is the time for the n-butyl lithium solution to complete the reaction. 2 to 24 hours is the total time of the two-stage reaction, for example, the first stage takes 4 hours, 5 hours, 6 hours, and the second stage takes 1 to 3 hours. The reaction time is preferably 3 to 8 hours, more preferably 4 to 6 hours.

[0028] Taking a specific reaction raw material and solvent (mixed solvent of n-heptane and ether) as an example, the reaction formula of step 1) is as follows:

[0029]

[0030] According to the present invention, the time for heating to room temperature in step 2) is 1 to 48 hours, preferably 1 to 24 hours, and more preferably 1 to 18 hours. Room temperature is also called general temperature or room temperature, which is generally defined as 25°C.

[0031] The conditions for reducing pressure and raising temperature include: pressure of 0.5 to 2 KPa.A (A represents absolute pressure) and temperature of 50 to 200°C.

[0032] In the present invention, the amines or amine hydrochlorides can be selected from N,N-dimethylaniline, N,N-dimethylaniline hydrochloride, N-methyldiphenylamine, N-methyldiphenylamine hydrochloride, triethylaniline, triethylaniline hydrochloride, N,N-dioctadecylaniline, N,N-dioctadecylaniline hydrochloride, N,N-dioctadecylmethylamine, N,N-dioctadecylmethylamine hydrochloride, dimethyloctadecylamine, dimethyloctadecylamine hydrochloride, dimethyldioctadecylbenzene-1,4-diamine, and dimethyldioctadecylbenzene-1,4-diamine hydrochloride.

[0033] According to the present invention, the amount of dichloromethane used can be 1 to 3 L, preferably 1 to 2 L, and more preferably 1 to 1.25 L per mole of the halogenated derivative of benzene; the molar ratio of boron trichloride to amines or amine hydrochlorides in the boron trichloride solution can be 1:1 to 1:2, preferably 1:1 to 1:1.5, and more preferably 1:1 to 1:1.2.

[0034] Taking N,N-dimethylaniline hydrochloride as an example of amines or amine hydrochlorides, the reaction formula of step 2) is as follows:

[0035]

[0036] The drying in step 3) of the present invention is vacuum drying, the drying temperature is 50-200° C., and the drying time is 1-5 hours;

[0037] In step 3), the volume ratio of the total amount of hexane to dichloromethane is 1:1 to 3:1, preferably 1:1 to 2:1.

[0038] Preferably, the amount of hexane used twice in step 3) is the same.

[0039] According to the present invention, the structure of the borate compound may be as shown in formula (2):

[0040]

[0041] In formula (2), A is NH or a carbon atom; B is a boron atom; Ar is a C6-C30 aryl group substituted with fluorine; R1', R2', and R3' are each independently selected from a C1-C30 alkyl group, a C1-C30 alkoxy group, a halogenated C1-C30 alkyl group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C6-C30 aryloxy group; and the substituent is selected from one or more of a C1-C30 alkyl group, a halogenated C1-C30 alkyl group, and a (C6-C30)aryl(C1-C30)alkyl group.

[0042] In the present invention, (C6-C30)aryl (C1-C30) alkyl may specifically include: benzyl, (2-methylphenyl)methyl, (3-methylphenyl)methyl, (4-methylphenyl)methyl, (2,3-dimethylphenyl)methyl, (2,4-dimethylphenyl)methyl, (2,5-dimethylphenyl)methyl, (2,6-dimethylphenyl)methyl, (3,4-dimethylphenyl)methyl, (4,6-dimethylphenyl)methyl, (2,3,4-trimethylphenyl)methyl, (2,3,5-trimethylphenyl)methyl, (2,3,6-trimethylphenyl)methyl, (3,4,5-trimethylphenyl)methyl, (2, methyl, (n-butylphenyl)methyl, (sec-butylphenyl)methyl, (tert-butylphenyl)methyl, (n-pentylphenyl)methyl, (neopentylphenyl)methyl, (n-hexylphenyl)methyl, (n-octylphenyl)methyl, (n-decylphenyl)methyl, (n-decylphenyl)methyl, (n-tetramethylphenyl)methyl, (n-tetradecylphenyl)methyl, naphthylmethyl or anthracenylmethyl, etc.

[0043] The present invention adopts low-temperature homogeneous reaction conditions, an alkane or ether solvent system under nitrogen protection, and n-butyl lithium reacts with a halogenated derivative of benzene at low temperature, further reacts with boron trichloride, and then reacts with a cationic part, such as amines or amine hydrochloride. By controlling a specific reaction process, such as a reaction raw material ratio, reaction time, temperature and other process parameters, a borate compound is synthesized. The raw materials used are cheap, the synthesis process is simple and easy, and the total yield is high. The reaction process can be synthesized in only one reactor, and the process route is suitable for industrial production.

[0044] According to a second aspect of the present invention, the present invention provides a use of a borate compound prepared by the above preparation method as a co-catalyst for a metallocene catalyst.

[0045] The borate compound product prepared by the invention does not contain catalyst poisons of olefin polymerization reaction and has good economic value as a co-catalyst of metallocene catalyst.

[0046] The substances and parameters not limited in the present invention can be selected according to the prior art and belong to the conventional technical means in the field. Unless otherwise specified, the operations and processing methods involved in the present invention belong to the conventional methods in the field, the instruments used are conventional instruments in the field, and the raw materials used are commercially available.

[0047] The present invention will be further described below with reference to the following examples, but is not limited to these examples.

[0048] In the following examples and comparative examples, the determination methods of the relevant data are as follows:

[0049] 1. Structure of borate compounds: The H-NMR, C-NMR, F-NMR and B-NMR spectra of the catalysts were measured on a Bruker-400 NMR spectrometer using deuterated chloroform as solvent at room temperature.

[0050] 2. Total molar yield of borate compound: molar yield = n(borate) / n(BCl3);

[0051] Wherein, n(BCl3) is the molar amount of BCl3 added to the system; n(borate) is the molar amount of borates of various structures prepared, n(borate) = m(borate) / M(borate), wherein m(borate) and M(borate) are the mass (g) and relative molecular weight (g / mol) of borate, respectively.

[0052] The mass of borate was measured by an electronic balance, brand: METTLER TOLEDO, equipment model: XPR6002SDR / AC.

[0053] Example 1

[0054] Add 10.0L of n-hexane to a 20L reactor filled with nitrogen, add 1111g of bromopentafluorobenzene, cool to -80°C, slowly add 2.813L of 1.6M n-butyl lithium in n-hexane solution, drop and react for 4 hours, keep -80°C for 1 hour after adding n-butyl lithium, then add 1.0L of 1M boron trichloride in n-hexane solution, react at -80°C for 1 hour, then slowly warm up to room temperature, and return to temperature for 6 hours. Remove the n-hexane solution under reduced pressure and temperature rise conditions (1KPa.A, 75°C) to obtain a viscous crude product. Add 5L of dichloromethane and 138.0g of triethylamine hydrochloride to the above crude product, stir and react for 1 hour, accompanied by the generation of white powder. Filter out the above white powder and collect the dichloromethane solution. Add 5.0L of hexane to the resulting solution, and stir during the addition of hexane. After the addition was completed, the mixture was allowed to stand for 1 hour, and then 5.0 L of hexane was added to the system, and stirring was required during the addition of hexane. After standing for 24 hours, the recrystallization mother liquor was filtered out and the crystals were collected. The obtained solid was heated and vacuum dried to obtain 651 g of N,N,-diethylethylamine tetrakis(pentafluorophenyl)borate, and the total molar yield was 83.4%.

[0055] Characterization: 1 H NMR (400MHz, CDCl3, 298K) δ / ppm: 1.21 (t, J=8.01Hz, 9H), 2.59 (m, 6H), 10.70 (br, 1H). 13 C{ 1 H}NMR (126MHz, CDCl3, 298K) δ / ppm: 148.6, 143.3, 142.84, 137.3, 130.40, 130.11, 120.7, 111.3, 42.34, 11.85. 19 F NMR (471MHz, CDCl3, 298K) δ / ppm: -132.72 (d, J=9.61Hz, 2F, oF), -162.46 (t, J=20.49Hz, 1F, pF), -166.61 (t, J=17.76Hz, 2F, mF). 11 B NMR (160MHz, CDCl3, 298K) δ / ppm: 16.59.HRMS (ESI / TOF) m / z: [M+H] + Calcd for C 30 H 17 BF 20 N 782.1056; Found 782.1127.

[0056] Example 2

[0057] Add 10.0L of n-hexane to a 20L reactor filled with nitrogen, add 1111g of bromopentafluorobenzene, cool to -80°C, slowly add 2.813L of 1.6M n-butyl lithium n-hexane solution, drop and react for 6 hours, keep -80°C for 1 hour after adding n-butyl lithium, then add 1.0L of 1M boron trichloride n-hexane solution, react at -80°C for 1 hour, then slowly warm up to room temperature, and return to temperature for 2 hours. Remove the n-hexane solution under reduced pressure and temperature rise conditions (1KPa.A, 75°C) to obtain a viscous crude product. Add 5L of dichloromethane and 220.0g of N-methyldiphenylamine hydrochloride to the above crude product, stir and react for 1 hour, accompanied by the generation of white powder. Filter out the above white powder and collect the dichloromethane solution. Add 6.0L of hexane to the resulting solution, and stir during the addition of hexane. After the addition was completed, the system was allowed to stand for 1 hour, and then 6.0 L of hexane was added to the system, and stirring was required during the addition of hexane. After standing for 24 hours, the recrystallization mother liquor was filtered out and the crystals were collected. The obtained solid was heated and vacuum dried to obtain 725 g of N-methyldiphenylamine tetrakis(pentafluorophenyl)borate, and the total molar yield was 84.0%.

[0058] Characterization: 1 H NMR (400MHz, CDCl3, 298K) δ / ppm: 7.24 (m, mH, 4H), 7.08 (m, J=7.49, pH, 2H), 6.64 (dd, J=7.57, 1.55, oH, 4H), 3.27 (s, 3H). 13 C{ 1 H} NMR (126MHz, CDCl3, 298K) δ / ppm: 148.6, 143.3, 148.08, 137.3, 129.28, 122.66, 120.17, 111.3, 38.02. 19 F NMR (471MHz, CDCl3, 298K) δ / ppm: -132.76 (d, J=9.61Hz, 2F, oF), -162.48 (t, J=20.49Hz, 1F, pF), -166.63 (t, J=17.76Hz, 2F, mF). 11 B NMR (160MHz, CDCl3, 298K) δ / ppm: 16.62.HRMS (ESI / TOF) m / z: [M+H] + Calcd for C 37 H 15 BF 20 N 864.0900; Found 864.0963.

[0059] Example 3

[0060] Add 10.0L dibutyl ether to a 20L reactor filled with nitrogen, add 1111g bromopentafluorobenzene, cool to -80°C, slowly add 2.813L of 1.6M n-butyl lithium in n-hexane solution, drop and react for 5 hours, keep -80°C for 1 hour after adding n-butyl lithium, then add 1.0L of 1M boron trichloride in n-hexane solution, react at -80°C for 1 hour, then slowly warm to room temperature, and return to temperature for 12 hours. Remove the dibutyl ether and n-hexane mixed solution under reduced pressure and temperature rise conditions (1KPa.A, 75°C) to obtain a viscous crude product. Add 5L of dichloromethane and 158.0g of N, N-dimethylaniline hydrochloride to the above crude product, stir and react for 0.5 hours, accompanied by the generation of white powder. Filter out the above white powder and collect the dichloromethane solution. Add 5.0L of hexane to the resulting solution, and stir during the addition of hexane. After the addition was completed, the mixture was allowed to stand for 1 hour, and then 5.0 L of hexane was added to the system. The mixture was stirred during the addition of hexane. After standing for 24 hours, the recrystallization mother liquor was filtered out and the crystals were collected. The obtained solid was heated and vacuum dried to obtain 729 g of N,N-dimethylaniline tetrakis(pentafluorophenyl)borate, with a total molar yield of 91.0%.

[0061] Characterization: 1 H NMR (400MHz, CDCl3, 298K) δ / ppm: 3.27 (s, 6H), 7.52 (m, 3H), 7.90 (m, 2H), 14.21 (br, 1H). 13 C{ 1 H} NMR (126MHz, CDCl3, 298K) δ / ppm: 148.6, 143.3, 142.84, 137.3, 130.40, 130.11, 120.7, 111.3, 46.50. 19 F NMR (471MHz, CDCl3, 298K) δ / ppm: -132.73 (d, J=9.61Hz, 2F, oF), -162.47 (t, J=20.49Hz, 1F, pF), -166.62 (t, J=17.76Hz, 2F, mF). 11 BNMR (160MHz, CDCl3, 298K) δ / ppm: 16.59.HRMS (ESI / TOF) m / z: [M+H] + Calcd for C 32 H 13 BF 20 N802.0743; Found 802.0712.

[0062] Example 4

[0063] Add 10.0L of n-hexane to a 20L reactor filled with nitrogen, add 1111g of bromopentafluorobenzene, cool to -80°C, slowly add 2.813L of 1.6M n-butyl lithium n-hexane solution, drop and react for 5 hours, keep -80°C for 1 hour after adding n-butyl lithium, then add 1.0L of 1M boron trichloride n-hexane solution, react at -80°C for 1 hour, then slowly warm to room temperature, and return to temperature for 12 hours. Remove the n-hexane solution under reduced pressure and temperature rise conditions (1KPa.A, 75°C) to obtain a viscous crude product. Add 5L of dichloromethane and 158.0g of N, N-dimethylaniline hydrochloride to the above crude product, stir and react for 0.5 hours, accompanied by the generation of white powder. Filter out the above white powder and collect the dichloromethane solution. Add 5.0L of hexane to the resulting solution, and stir during the addition of hexane. After the addition was completed, the mixture was allowed to stand for 1 hour, and then 5.0 L of hexane was added to the system, and stirring was required during the addition of hexane. After standing for 24 hours, the recrystallization mother liquor was filtered out and the crystals were collected. The obtained solid was heated and vacuum dried to obtain 642 g of N,N-dimethylaniline tetrakis(pentafluorophenyl)borate, and the total molar yield was 80.1%.

[0064] Characterization: 1 H NMR (400MHz, CDCl3, 298K) δ / ppm: 3.27 (s, 6H), 7.52 (m, 3H), 7.90 (m, 2H), 14.21 (br, 1H). 13 C{ 1 H}NMR (126MHz, CDCl3, 298K) δ / ppm: 148.6 (fluorobenzene), 143.3, 142.84 (anilinium benzene), 137.3, 130.40, 130.11, 120.7, 111.3, 46.50. 19 F NMR (471MHz, CDCl3, 298K) δ / ppm: -132.70 (d, J=9.61Hz, 2F, oF), -162.44 (t, J=20.49Hz, 1F, pF), -166.59 (t, J=17.76Hz, 2F, mF). 11 B NMR (160MHz, CDCl3, 298K) δ / ppm: 16.59.HRMS (ESI / TOF) m / z: [M+H] + Calcd for C 32 H 13 BF 20 N 802.0743; Found 802.0712.

[0065] Example 5

[0066] Add 10.0L dibutyl ether to a 20L reactor filled with nitrogen, add 1111g bromopentafluorobenzene, cool to -80°C, slowly add 2.813L of 1.6M n-butyl lithium in n-hexane solution, drop and react for 5 hours, keep -80°C for 1 hour after adding n-butyl lithium, then add 1.0L of 1M boron trichloride in n-hexane solution, react at -80°C for 1 hour, then slowly warm to room temperature, and return to temperature for 12 hours. Remove the dibutyl ether and n-hexane mixed solution under reduced pressure and temperature rise conditions (1KPa.A, 75°C) to obtain a viscous crude product. Add 10L dichloromethane and 599.0g N, N-dioctadecane aniline to the above crude product, stir and react for 2 hours, accompanied by the generation of white powder. Filter out the above white powder and collect the dichloromethane solution. Add 5.0L hexane to the resulting solution, and stir during the addition of hexane. After the addition was completed, the system was allowed to stand for 1 hour, and then 5.0 L of hexane was added to the system, and stirring was required during the addition of hexane. After standing for 24 hours, the recrystallization mother liquor was filtered out and the crystals were collected. The obtained solid was heated and vacuum dried to obtain 1138 g of N, N-dioctadecylaniline tetrakis (pentafluorophenyl) borate, and the total molar yield was 89.0%.

[0067] Characterization: 1 H NMR (400MHz, CDCl3, 298K) δ / ppm: 3.27 (s, 6H), 7.52 (m, 3H), 7.90 (m, 2H), 14.21 (br, 1H). 13 C{ 1 H} NMR (126MHz, CDCl3, 298K) δ / ppm: 148.6, 143.3, 142.84, 137.3, 130.40, 130.11, 120.7, 111.3, 46.50. 19 F NMR (471MHz, CDCl3, 298K) δ / ppm: -132.72 (d, J=9.61Hz, 2F, oF), -162.46 (t, J=20.49Hz, 1F, pF), -166.61 (t, J=17.76Hz, 2F, mF). 11 BNMR (160MHz, CDCl3, 298K) δ / ppm: 16.59.HRMS (ESI / TOF) m / z: [M+H] + Calcd for C 32 H 13 BF 20 N802.0743; Found 802.0712.

[0068] Comparative Example 1

[0069] Under nitrogen protection, a solution of pentafluorobenzene (16.8 g, 100.0 mmol) and dibutyl ether (100 mL) was cooled to -40 ° C, and 20 wt% of water was added. Sec-butyl lithium / hexane solution (28.2 g, 88.0 mmol) was added, and the mixture was stirred at -30 ° C to -40 ° C for 2 hours. Thereafter, boron trifluoride-ether complex (2.84 g, 20.0 mmol) was added at -40 ° C, and the temperature was raised to room temperature within 2 hours. After stirring overnight at room temperature, octane (200 mL) was added, and after distilling off ether and hexane under heating, octane was further distilled off under heating to recover about 30% of the added amount. After filtering off the precipitated lithium fluoride, octane was removed and dried to obtain a white solid of lithium tetrakis (pentafluorophenyl) borate with a yield of 67.3%.

[0070] 1.1 equivalents of tributylammonium chloride aqueous solution and the obtained lithium tetrakis(pentafluorophenyl)borate were mixed and dissolved in the aqueous solution, and stirred to react to form precipitated white crystals. The obtained crystals were filtered, washed with water, and then vacuum dried to obtain tributylammonium tetrakis(pentafluorophenyl)borate with a yield of 95.2%. The total molar yield was 64.1%.

[0071] Comparative Example 2

[0072] Under nitrogen protection, add 50g of pentafluorobromobenzene and 250mL of n-pentane to a four-necked flask, cool to -45°C, drop 76mL of n-butyllithium (2.5M) n-hexane solution, keep the internal temperature below -40°C, stir at -45°C for 4h, then start to drop 4.94g of trimethyl borate, add dropwise, keep stirring at -45°C for 4h, add 200mL of water to quench, extract twice with 200mL of ether respectively, combine the organic phases, add anhydrous magnesium sulfate to dry, and spin dry to obtain crude lithium tetrakis(pentafluorophenyl)borate.

[0073] Under nitrogen protection, 100 g of n-heptane and 60 g of ether were added, refluxed, filtered, and vacuum dried to obtain 32 g of lithium tetrakis(pentafluorophenyl)borate ether complex (each molecule of lithium salt contained 2.5 molecules of ether), with a yield of 73%.

[0074] 1.1 equivalents of N,N-dimethylanilinium chloride aqueous solution was reacted with the obtained tetrakis(pentafluorophenyl)borate lithium ether complex to generate precipitated white crystals. The obtained crystals were filtered, washed with water, and then vacuum dried to obtain N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate with a yield of 92.3%.

[0075] The total molar yield was 67.4%.

[0076] The comparative example is a common step-by-step method for synthesizing the target product. Compared with the comparative example, the borate compound prepared by the method of the present invention has a higher comprehensive yield, and the total molar yield can reach more than 90%. The starting raw materials and solvents of the present invention are cheap chemical raw materials, and the reaction process can be synthesized in one step in only one reactor, reducing the loss of reactants caused by transfer, isolating water and oxygen during the reaction process, not using water phase reaction, and will not contain catalyst poisons for olefin polymerization reactions. It can be used as a boron co-catalyst in catalytic reactions with high requirements for raw material water and oxygen, such as metallocene-catalyzed olefin polymerization processes, and is suitable for industrial production and has good economic value.

[0077] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing a borate compound, characterized in that: The preparation method comprises the following steps: 1) Mix the halogenated derivative of benzene and the solvent, add n-butyl lithium solution dropwise at -60°C to -100°C under nitrogen protection and react for 2 to 24 hours, then add boron trichloride solution and continue to react for 1 to 36 hours; 2) heating the reaction mixture obtained in step 1) to room temperature, then removing the solvent by heating under reduced pressure to obtain a crude product, adding dichloromethane and amines or amine hydrochlorides to the crude product, and stirring the reaction for 0.5 to 4 hours; 3) filtering the product obtained in step 2), adding hexane to the filtrate and stirring, then standing for 0.5 to 5 hours, adding hexane again and stirring, standing for 12 to 48 hours, then filtering and collecting the crystals, and drying to obtain the borate compound.

2. The method for preparing a borate compound according to claim 1, wherein: The structure of the halogenated derivative of benzene is shown in formula (1): In formula (1), R1 to R6 are each selected from fluorine, chlorine, bromine and iodine.

3. The method for preparing a borate compound according to claim 1, wherein: The solvent in step 1) is an alkane and / or ether solvent, and the alkane and / or ether solvent is selected from at least one of n-octane, n-heptane, n-hexane, isohexane, cyclohexane, methylcyclohexane, petroleum ether, ethyl ether and dibutyl ether.

4. The method for preparing a borate compound according to claim 1 or 3, wherein: The amount of solvent used in step 1) is 2 to 5 L, preferably 2 to 2.5 L, and more preferably 2 to 2.25 L per mole of the halogenated derivative of benzene; the amount of n-butyl lithium used in the n-butyl lithium solution is 1 mol; the amount of boron trichloride used in the boron trichloride solution is 0.15 to 0.35 mol, preferably 0.2 to 0.25 mol; Preferably, the solvent of the n-butyl lithium solution and the boron trichloride solution is the same as the solvent in step 1).

5. The method for preparing a borate compound according to claim 1, wherein: The time for heating to room temperature in step 2) is 1 to 48 hours; the conditions for reducing pressure and heating include: pressure of 0.5 to 2 KPa.A and temperature of 50 to 200°C.

6. The method for preparing a borate compound according to claim 1, wherein: The amines or amine hydrochlorides are selected from N,N-dimethylaniline, N,N-dimethylaniline hydrochloride, N-methyldiphenylamine, N-methyldiphenylamine hydrochloride, triethylaniline, triethylaniline hydrochloride, N,N-dioctadecylaniline, N,N-dioctadecylaniline hydrochloride, N,N-dioctadecylmethylamine, N,N-dioctadecylmethylamine hydrochloride, dimethyloctadecylamine, dimethyloctadecylamine hydrochloride, dimethyldioctadecylbenzene-1,4-diamine, and dimethyldioctadecylbenzene-1,4-diamine hydrochloride.

7. The method for preparing a borate compound according to claim 1, wherein: The amount of dichloromethane used is 1 to 3 L, preferably 1 to 2 L, and more preferably 1 to 1.25 L per mole of the halogenated derivative of benzene; the molar ratio of boron trichloride to amines or amine hydrochlorides in the boron trichloride solution is 1:1 to 1:2, preferably 1:1 to 1:1.5, and more preferably 1:1 to 1:1.

2.

8. The method for preparing a borate compound according to claim 1, wherein: The drying in step 3) is vacuum drying, the drying temperature is 50-200° C., and the drying time is 1-5 h; In step 3), the volume ratio of the total amount of hexane to dichloromethane is 1:1 to 3:1, preferably 1:1 to 2:1; preferably, the amount of hexane used twice is the same.

9. The method for preparing a borate compound according to claim 1, wherein: The structure of the borate compound is shown in formula (2): In formula (2), A is NH or a carbon atom; B is a boron atom; Ar is a C6-C30 aryl group substituted with fluorine; R1', R2', and R3' are each independently selected from a C1-C30 alkyl group, a C1-C30 alkoxy group, a halogenated C1-C30 alkyl group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C6-C30 aryloxy group; and the substituent is selected from one or more of a C1-C30 alkyl group, a halogenated C1-C30 alkyl group, and a (C6-C30)aryl(C1-C30)alkyl group.

10. Use of the borate compound obtained by the preparation method according to any one of claims 1 to 9 as a co-catalyst for a metallocene catalyst.

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