Synthesis method of soluble organic boron salt cocatalyst

Abstract

The invention provides a synthesis method of a soluble organic boron salt cocatalyst, which comprises the following steps: step 1, putting a certain amount of boron salt and a certain amount of organic amine into a dry organic solvent, and slowly introducing dry halogen hydride gas under mechanical stirring; and 2, after stirring for a certain time, filtering the obtained reaction liquid to remove insoluble substances, and carrying out vacuum decompression to remove the solvent to obtain the viscous soluble organic boron salt cocatalyst. The method provided by the invention can effectively avoid the disadvantage that large-scale production cannot be realized in the existing reaction, is more beneficial to the realization of industrial large-scale production requirements, and improves the production speed and purity of the soluble organic boron salt cocatalyst at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemical synthesis, and in particular relates to a method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that dry hydrogen halide gas is used to participate in the reaction to directly prepare an anhydrous soluble organic boron salt co-catalyst. Background Art

[0002] As an important co-catalyst of metallocene catalyst system, organic boron salt has a very important use in the field of olefin polymerization. Organic boron salt anions can effectively disperse the negative charge of the boron center to make it a weakly coordinated anion. As a balance of the cationic metal center in olefin polymerization, it exhibits unique catalytic performance. The use of organic boron salt co-catalyst can greatly reduce the amount of methylaluminoxane and alkyl aluminum used in the olefin polymerization industry. Common organic boron salts are triphenylcarbon-tetrakis(pentafluorophenyl)borate, N, N-dimethylaniline-tetrakis(pentafluorophenyl)borate, etc. These organic boron salts have good solubility in aromatic hydrocarbon solvents, but very low solubility in aliphatic alkanes, and aliphatic alkanes are mainly used as reaction solvents in industrial polymerization. The solubility of organic boron salts in alkanes limits their industrial application. In 1999, Down Company developed a soluble organic boron salt co-catalyst, which mainly uses long-chain organic amines combined with tetrakis(pentafluorophenyl)boron anions. The resulting organic boron salt can be dissolved in cyclohexane or methylcyclohexane. However, in the conventional preparation method, hydrochloric acid is used as a reagent, and water is introduced. Due to the high viscosity of the soluble organic boron salt, it is impossible to perform recrystallization purification, and the residual water cannot be removed, resulting in low activity of the co-catalyst during use. Recently, Shi Xibi and others from South Korea reported the removal of water from soluble organic boron salts by an azeotropic method, but this method is very complicated to operate and is not conducive to scale-up production. The patent of Chen Yanhui and others shows that the boron salt and the hydrochloride of the organic amine are used together by ball milling to directly obtain an anhydrous soluble organic boron salt co-catalyst. However, the ball milling time is relatively long and the amount of ball milling is relatively small, which limits the scale-up production of such catalysts.

[0003] Therefore, from the perspective of large-scale industrial application, it is necessary to develop a simpler operation method to prepare a water-free soluble organic boron salt co-catalyst. Summary of the invention

[0004] The purpose of the present invention is to provide a method for synthesizing a soluble organic boron salt co-catalyst, aiming to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: using dry anhydrous hydrogen chloride as a reaction reagent, reacting with boron salt and organic amine in a solvent to directly obtain a water-free soluble organic boron salt co-catalyst. This reaction is simple to operate, low in risk, and very suitable for industrial scale-up production.

[0006] A method for synthesizing a soluble organic boron salt co-catalyst comprises the following steps:

[0007] Step 1, placing a certain amount of boron salt and a certain amount of organic amine in a dry organic solvent, and slowly introducing dry hydrogen halide gas under mechanical stirring;

[0008] Step 2, after stirring for a certain period of time, the obtained reaction solution is filtered to remove insoluble matter, and the solvent is removed by vacuum decompression to obtain a viscous soluble organic boron salt co-catalyst. The "organic solvent" described in the present invention can be a single organic solvent or a mixture of multiple organic solvents. This organic solvent can be alkanes, halogenated alkanes, aromatic hydrocarbons, halogenated aromatic hydrocarbons, cycloalkanes, etc., among which cycloalkanes and halogenated alkanes are preferred. The medium can contain one or more cycloalkanes, halogenated alkanes, and in different cases, it can also contain one or more other types of components, such as alkanes, aromatic hydrocarbons. Cyclohexane, methylcyclohexane and dichloromethane are preferred organic solvents in the implementation of the present invention.

[0009] The "hydrogen halide" gas described in the method of the present invention can be hydrogen chloride gas or hydrogen bromide gas, or a mixture of the two gases. Hydrogen chloride is preferred. In the present invention, "boron salt" should be understood as tetraaryl boron salt when not specified, and the aryl group can be phenyl, naphthyl, or polyfluoroaryl with multiple fluorine atoms substituted. Polyfluoroaryl refers to a fluorine-containing aryl having at least two fluorine atoms directly bonded to the aromatic ring, or at least two perfluoroalkyl groups, or at least one fluorine atom and at least one perfluoroalkyl group. Preferably, at least two fluorine atoms or at least two perfluoroalkyl groups are directly bonded to the aromatic ring. Each position on the aromatic ring of the fluoroaryl that is not a fluorine atom or a perfluoroalkyl group can be substituted with a hydrogen atom, an alkyl group, or an alkoxy group. The aromatic ring of the fluoroaryl includes, but is not limited to, benzene, naphthalene, anthracene, biphenyl, and phenanthrene. Benzene and naphthalene are preferred parts. Perfluoroalkyl groups include alkyl and aryl perfluorinated compounds; including but not limited to trifluoromethyl, pentafluoroethyl, pentafluorophenyl, and heptafluoronaphthyl. The hydrocarbyl substituent of the aryl is preferably a C1 to C24 alkyl or a C6 to C30 aryl or aralkyl. Examples including but not limited to are methyl, ethyl, isopropyl, tert-butyl, cyclopentyl, methylcyclohexyl, decyl, phenyl, tolyl, xylyl, benzyl, naphthyl. The alkoxy preferably has a C1 to C24 alkyl moiety. Alternative but not limited examples of alkoxy are methoxy, ethoxy, isopropoxy, cyclohexyl and methylcyclopentyloxy. Examples of fluoroaryl groups that may be present on the borate portion of the present invention include 3,5-bis(trifluoromethyl)phenyl, 2,4,6-tris(trifluoromethyl)-phenyl, 4-[tri(isopropyl)silyl]-tetrafluorophenyl, 4-[dimethyl(tert-butyl)silyl]-tetrafluorophenyl, 4′-(methyloxy)-octafluoro-1-biphenyl-4-yl, 2,3-bis(pentafluoroethyl)-naphthyl, 2-(isopropoxy)-hexafluoronaphthyl, 9,10-bis(heptafluoropropyl)-heptafluoroanthracenyl, 9,10-bis(p-tolyl)-heptafluorophenanthranyl.

[0010] Preferably, at most two substituents on the ring of the fluoroaryl are hydrocarbon groups, perfluoroalkyl groups, and the remaining substituents are fluorine atoms. Preferred fluoroaryl groups are those in which all substituents are fluorine atoms. Examples of such groups are pentafluorophenyl, nonafluoro-1-biphenyl-4-yl, nonafluoro-1-biphenyl-3-yl, 1-heptafluoronaphthyl, 2-heptafluoronaphthyl, 7-nonafluoroanthracenyl, 9-nonafluorophenanthrenyl and similar groups. Preferred perfluoroaryl groups include pentafluorophenyl and heptafluoronaphthyl.

[0011] In the present invention, "organic amine" refers to an organic amine containing a long organic chain, and the molecular formula is NR1R2R3, R1, R2, and R3 may be the same or different, and may be an alkyl or aromatic substituent containing a C6-C30 chain, such as phenyl, o-methylphenyl, etc. The reaction temperature range in the present invention may be -20°C to 80°C. More preferably, the condition is 0°C to 40°C.

[0012] The following examples are given for illustrative purposes and are not intended to limit the scope of the present invention.

[0013] Example 1

[0014] In a three-necked flask with mechanical stirring, add K[B(C6F5)4](7.18g, 10mmol) and (C18H37)2NMe(5.36g, 10mmol) and 200ml of dichloromethane. Stirring is started at 20℃, and dry hydrogen bromide gas is slowly introduced. The suspension is stirred for 1 hour and then filtered. The obtained dichloromethane solution is vacuum dried to obtain a light yellow viscous liquid. The yield is 92%.

[0015] Example 2

[0016] In a three-necked flask with mechanical stirring, add K[B(C6F5)4](7.18g, 10mmol) and (C18H37)2NMe(5.36g, 10mmol) and 200ml of methylcyclohexane. Stirring is started at 60℃, and dry hydrogen chloride gas is slowly introduced. The suspension is stirred for 2 hours and then filtered. The obtained methylcyclohexane solution is vacuum dried to obtain a light yellow viscous liquid. The yield is 88%.

[0017] Example 3

[0018] In a three-necked flask with mechanical stirring, add Na[B(C6F5)4](7.02g, 10mmol) and (C18H37)2NMe(5.36g, 10mmol) and 200ml of methylcyclohexane. Stirring is started at 30℃, and dry hydrogen chloride gas is slowly introduced. The suspension is stirred for 1 hour and then filtered. The obtained methylcyclohexane solution is vacuum dried to obtain a light yellow viscous liquid. The yield is 84%.

[0019] Example 4

[0020] In a three-necked flask with mechanical stirring, add Li[B(C6F5)4](6.86g, 10mmol) and (C18H37)2NMe(16.08g, 30mmol) and 200ml cyclohexane. Stirring is started at 20℃, and dry hydrogen chloride gas is slowly introduced. The suspension is stirred for 1 hour and then filtered. The obtained cyclohexane solution is vacuum dried to obtain a light yellow viscous liquid. The yield is 65%.

[0021] Example 5

[0022] In a three-necked flask with mechanical stirring, add K[B(C6F5)4](7.18g, 10mmol) and (C16 H33)2NMe(3.40g, 10mmol) and 200ml of dichloromethane. Stirring is started at 0℃, and dry hydrogen chloride gas is slowly introduced. The suspension is stirred for 1 hour and then filtered. The obtained dichloromethane solution is vacuum dried to obtain a light yellow viscous liquid. The yield is 74%.

[0023] Example 6

[0024] In a three-necked flask with mechanical stirring, add K[B(C6F5)4](7.18g, 10mmol) and (C12H25)2NEt(3.81g, 10mmol) and 200ml of dichloromethane. Stirring is started at 20℃, and dry hydrogen chloride gas is slowly introduced. The suspension is stirred for 1 hour and then filtered. The obtained dichlorohexane solution is vacuum dried to obtain a light yellow viscous liquid. The yield is 77%.

[0025] Example 7

[0026] In a three-necked flask with mechanical stirring, add K[B(C6F5)4](7.18g, 10mmol) and PhN(C18H37)2(5.98g, 10mmol) and 200ml of dichloromethane. Stirring is started at 20℃, and dry hydrogen chloride gas is slowly introduced. The suspension is stirred for 1 hour and then filtered. The obtained dichlorohexane solution is vacuum dried to obtain a light yellow viscous liquid. The yield is 81%.

[0027] Example 8

[0028] In a three-necked flask with mechanical stirring, add K[B(C6F5)4](7.18g, 10mmol) and (2-Me-Ph)N(C12H25)2(6.12g, 10mmol) and 200ml of dichloromethane. Stirring is started at 20℃, and dry hydrogen chloride gas is slowly introduced. The suspension is stirred for 1 hour and then filtered. The obtained dichlorohexane solution is vacuum dried to obtain a light yellow viscous liquid. The yield is 85%.

[0029] The invention is susceptible to considerable variations in practice.The foregoing description is therefore not intended to be limiting and should not be construed as limiting the invention to the particular exemplifications given hereinabove.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention uses dry hydrogen halide gas as a reaction reagent to react with boron salt and organic amine to directly obtain a water-free soluble organic boron salt co-catalyst, which can effectively avoid the disadvantage that the existing reaction cannot be produced on a large scale, and is more conducive to achieving industrial large-scale production requirements.

Claims

1. A method for synthesizing a soluble organic boron salt co-catalyst, characterized in that: The following steps are involved: Step 1, placing a certain amount of boron salt and a certain amount of organic amine in a dry organic solvent, and slowly introducing dry hydrogen halide gas under mechanical stirring; Step 2: After stirring for a certain period of time, the obtained reaction solution is filtered to remove insoluble matter, and the solvent is removed under vacuum to obtain a viscous soluble organic boron salt co-catalyst.

2. The method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that: In the step 1, an anhydrous organic solvent is used for the reaction, and dry hydrogen halide gas is used as a reaction reagent.

3. The method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that: In the step 2, unreacted raw materials are removed by direct filtration, and the solvent is removed by vacuum to directly obtain a water-free soluble organic boron salt co-catalyst.

4. The method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that: The temperature in the screw-stirred tubular reactor is controlled to be in the range of -30 to -80°C by circulating low-temperature liquid.

5. The method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that: The molar ratio of the boron salt to the organic amine is in the range of 1:1 to 1:

3.

6. The method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that: The reaction temperature during the passage of hydrogen halide is -20-80°C.

7. The method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that: The hydrogen chloride may be hydrogen chloride or hydrogen bromide.

8. The method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that The boron salt used may be a phenyl boron salt or a perfluoroaryl boron salt.

9. The method for synthesizing a soluble organic boron salt co-catalyst according to claim 1, characterized in that The organic solvent used can be aromatic hydrocarbons such as toluene, xylene, chlorobenzene, etc., and cyclohexane, methylcyclohexane, and halogenated alkanes can also be used.