A method for preparing a boron trifluoride complex catalyst

Abstract

This invention provides a method for preparing a boron trifluoride complex catalyst, comprising the following steps: using haloalkyl alcohols and cycloalkylalkyl ethers as complexing agents, reacting them with BF3 gas in a first reactor until the product density in the first reactor reaches 1.15–1.3 g / cm³. 3 The overflow flows into the second reactor, and BF3 is continuously introduced until the product density in the second reactor reaches 1.25–1.35 g / cm³. 3 Upon reaching this point, a boron trifluoride complex catalyst is obtained. The process of this invention utilizes two reactors connected in series, enhancing mass and heat transfer. This allows the complexing agent containing lone pairs of electrons and boron trifluoride to mix rapidly in a continuous flow reactor, shortening the reaction time, avoiding side reactions caused by excessively long reaction times, and improving the stability of the catalyst.

Description

Technical Field

[0001] This invention belongs to the field of polyalphaolefin oil catalysts, specifically relating to a method for preparing a boron trifluoride complex catalyst. Background Technology

[0002] Polyalphaolefin (PAO) base oil is a Group IV lubricating oil base oil. Compared with traditional mineral lubricating oil base oils (Groups I, II, and III), it has advantages such as excellent viscosity-temperature properties, good low-temperature fluidity, excellent high-temperature oxidation resistance, good shear stability, and low evaporation loss. It is particularly suitable for extreme environments such as high loads, high speeds, high vacuum, high-energy radiation, and strong oxidizing media. Viscosity is one of the most important physical properties of PAO base oils; conventionally, a viscosity below 100℃ is considered acceptable. 2 The product is called low-viscosity PAO base oil, with a viscosity of 10-40 mm at 100℃. 2 Products with a viscosity between 0.5 and 0.5 are called medium viscosity PAO base oils; those with a viscosity higher than 40 mm at 100°C are called medium viscosity PAO base oils. 2 The product with a viscosity of / s is called high-viscosity PAO base oil. Among them, low-viscosity PAO base oil is the most in-demand lubricating oil base oil product, accounting for 80% of PAO. The catalysts used to synthesize low-viscosity PAO base oil are mainly boron trifluoride cationic catalysts.

[0003] Currently, the production process of boron trifluoride cation complexes involves introducing boron trifluoride gas into a stirred batch reactor, heating or cooling the reactants through a jacket and coils. When the pressure in the batch reactor exceeds a certain value, the boron trifluoride gas supply is stopped, and the reactor is pressure-maintained and stirred for 3-8 hours. Finally, the pressure is released to obtain the boron trifluoride complex. However, due to the highly corrosive nature of boron trifluoride, the stirring paddle and heating / cooling coils of the batch reactor are easily corroded, resulting in low heat exchange efficiency. Furthermore, the inherent safety of the stirred reactor means that the reaction pressure cannot be too high. All these factors contribute to the long reaction time, inability to produce continuously, and low safety performance of the batch production process for boron trifluoride complexes, contradicting the principles of green chemistry. Therefore, new synthesis technologies urgently need to be explored and developed.

[0004] To address the aforementioned issues, CN202110375646.8 discloses a method for the continuous polymerization synthesis of boron trifluoride complexes. This method employs a microchannel reactor, where a complexing agent (one of acetonitrile, petroleum ether, monoethylamine, ethyl acetate, anisole, or methyl ether) and BF3 gas are simultaneously introduced into the microchannel reactor to undergo a complexation reaction. The resulting reaction products are then separated to obtain the target product, the boron trifluoride complex. CN202110844868.X discloses a continuous synthesis method and reaction apparatus for boron trifluoride complexes. The continuous flow reactor is one or more of a microchannel reactor, tubular reactor, stacked mixer, and static mixer. This significantly shortens the diffusion time of the organic compound containing lone pairs of electrons and boron trifluoride in the reactor. The organic compound containing lone pairs of electrons and boron trifluoride can mix rapidly in the continuous flow reactor, enhancing mass and heat transfer processes, shortening reaction time, and greatly improving the efficiency of the synthesis reaction. Simultaneously, it avoids side reactions caused by excessively long reaction times, thus increasing the yield of the target product, the boron trifluoride complex.

[0005] From the perspective of the types of boron trifluoride cationic complexes, the complexing agents used in the above technical solutions are mostly substances containing lone pair electrons, such as acetonitrile, petroleum ether, ethylamine, ethyl acetate, anisole, methyl ether, and furan compounds. These complexes form with BF3, and the concentration of BF3 in these complexes has a maximum value. Furthermore, these complexes are prone to decomposition at high temperatures, requiring low-temperature storage. To overcome the instability of existing BF3 catalysts, a third component can be added to improve catalyst stability. For example, patent CN02144631.8 provides a method using phenylalkyl ether as the third component to react with BF3 and C1-C1... 10 The catalyst prepared by alcohol complex has significantly improved stability and a longer storage time, and can be stored for 10 to 15 days in an environment below 0°C. However, this method requires the temperature to be controlled within the range of 0 to -30°C during catalyst preparation, which is too low and difficult to operate. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing boron trifluoride complex catalysts, so as to solve the problems of harsh preparation conditions and unstable catalysts prepared by existing methods.

[0007] To achieve the above objectives, this invention provides a method for preparing a boron trifluoride complex catalyst, comprising the following steps: using haloalkyl alcohols and cycloalkylalkyl ethers as complexing agents, performing a complexation reaction with BF3 gas in a first reactor, until the product density in the first reactor reaches 1.15–1.3 g / cm³. 3 The overflow flows into the second reactor, and BF3 is continuously introduced until the product density in the second reactor reaches 1.25–1.35 g / cm³. 3 When the time is right, a boron trifluoride complex catalyst is obtained.

[0008] The method for preparing the boron trifluoride complex catalyst of the present invention is characterized in that the haloalkyl alcohol is a C3-C5 chloroalcohol, preferably chloropropanol, and the cycloalkyl ether is cyclopentylmethyl ether and / or cyclohexylethyl ether.

[0009] The method for preparing the boron trifluoride complex catalyst of the present invention is characterized in that the mass ratio of haloalkyl alcohol to cycloalkyl ether is 1 to 10:1.

[0010] The method for preparing the boron trifluoride complex catalyst of the present invention is characterized in that the mass ratio of haloalkyl alcohol to cycloalkyl ether is 3 to 8:1.

[0011] The method for preparing the boron trifluoride complex catalyst of the present invention is characterized in that the reaction temperature of the first reaction vessel and the second reaction vessel is controlled at 5-15°C during the preparation process.

[0012] The method for preparing the boron trifluoride complex catalyst of the present invention is characterized in that the flow rate of BF3 in the first reaction vessel is 15-30 L / h and the pressure is 0.1-0.5 MPa.

[0013] The method for preparing the boron trifluoride complex catalyst of the present invention is characterized in that the flow rate of BF3 in the second reaction vessel is 5-15 L / h and the pressure is 0.1-0.5 MPa.

[0014] The method for preparing the boron trifluoride complex catalyst of the present invention is characterized in that the mass ratio of BF3 to complexing agent in the boron trifluoride complex catalyst is 0.6 to 1:1.

[0015] The method for preparing the boron trifluoride complex catalyst of the present invention is characterized in that the reaction temperature is controlled with an accuracy of ±2℃ during the preparation process.

[0016] Beneficial effects of this invention:

[0017] This invention utilizes two reactors connected in series, enhancing mass and heat transfer. This allows for rapid mixing of the complexing agent containing lone pairs of electrons and boron trifluoride in a continuous flow reactor, shortening the reaction time, avoiding side reactions caused by excessively long reaction times, and improving catalyst stability. Simultaneously, by controlling the density range of the products in each reactor, the degree of complexation is controlled, thereby achieving low-temperature controllable temperature of the complexing system and ensuring product quality. This technical solution involves the combined use of haloalkyl alcohols and cyclopentyl methyl ether or cyclohexyl ethyl ether. The acidity of the catalyst is adjusted through the inductive effect of different functional groups in the composite complexing agent, meeting the requirements for catalytic α-olefin oligomerization and obtaining the main component of low-viscosity PAO. Detailed Implementation

[0018] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0019] raw material:

[0020] BF3 gas, purity > 99.5%.

[0021] Chloropropanol, purity > 99%.

[0022] Cyclopentyl methyl ether, purity > 99%.

[0023] Cyclohexyl ethyl ether, purity > 99%.

[0024] Catalyst evaluation methods:

[0025] Catalyst stability evaluation:

[0026] The catalyst was stored at 15°C or below for 45 days, and its appearance was observed for any obvious changes.

[0027] Catalytic performance evaluation: The performance was evaluated using a conventional small-scale batch evaluation method in a 1L polymerization reactor. 2g of complexing catalyst and 200g of 1-decene were added, BF3 was introduced, the reactor pressure was controlled at 0.2 MPa, the reaction temperature at 30℃, and the reaction was carried out for 2 hours. The resulting product was then washed with water, and its composition was determined.

[0028] Catalyst preparation method:

[0029] 1) Before the complexation begins, clean the reactor with 300ml of purified cyclohexane at a temperature of 100℃ for 0.5h-1h. After releasing the cyclohexane, purge the polymerization reactor with high-purity nitrogen to ensure that air and trace amounts of water are removed from the polymerization reactor.

[0030] 2) The complexing agent is refined using a molecular sieve drying tower, and the water content in the complexing agent is less than 20 ppm.

[0031] 3) First, introduce the complexing agent into reactor I, then start the BF3 flow controller of reactor I, set the flow rate, and start the cooling equipment at the same time. Heat is extracted through coils, shaft cooling and external circulation to control the reaction temperature and pressure of reactor I and carry out the complexation reaction. When the density of the reactants in reactor I reaches the qualified level, the reactants in reactor I are overflowed into reactor II. Reactors I and II reach complexation equilibrium. After the density of reactor II reaches the qualified level, the reactants are discharged online to the product storage tank or transport tank.

[0032] Example 1

[0033] The complexation reaction was carried out using the polymerization steps described above. After pretreatment of the reactor, the complexation reaction began: ① 10 kg of complexing agent chloropropanol and cyclopentyl methyl ether (mass ratio of 10:1) were added to reactor I at a flow rate of 20 L / h. The cooling system was started to lower the temperature to 10℃. The BF3 flow controller was started and the flow rate was set to 15 L / h. During normal complexation, the pressure inside the reactor was maintained at 0.1-0.5 MPa, and the reaction temperature inside the complexation reactor was maintained at 10℃. The temperature control was stable. During the complexation process, the product density was measured every 2 hours, and the density was 1.28 g / cm³. 3 Overflow into reactor II. ② Control the temperature of reactor II to 10℃ and the complexation temperature to 12℃. Start the BF3 flow controller, set the flow rate to 5L / h, turn on the stirrer, and maintain the pressure at 0.1-0.5Mpa. During the complexation process, repeat the process every 2 hours. The product density is measured to be 1.35g / cm³. 3 The product is unloaded from the production line and transferred to a product storage tank or transport tank for BF3 content analysis and performance evaluation. Complexation conditions and product performance analysis are listed in Table 1.

[0034] Example 2

[0035] The same complexation method as in Example 1 was used, with the following differences: ① 10 kg of complexing agent chloropropanol and cyclopentyl methyl ether (mass ratio of 5:1) were pre-added to reactor I at a flow rate of 35 L / h. The temperature was lowered to 5°C, and the BF3 flow controller was started, setting the flow rate to 30 L / h. The reaction temperature inside the complexation reactor was maintained at 7°C, and the temperature control was stable. During the complexation process, the product density was measured every 2 hours, and the density was 1.20 g / cm³. 3 Overflow into reactor II. ② Control the temperature of reactor II to 5℃ and the complexation temperature to 6℃. Start the BF3 flow controller, set the flow rate to 10L / h, turn on the stirrer, and maintain the pressure at 0.1-0.5Mpa. During the complexation process, repeat the process every 2 hours. The product density is measured to be 1.25g / cm³. 3 .

[0036] Example 3

[0037] The same complexation method as in Example 1 was used, with the following differences: ① 10 kg of complexing agent chloropropanol and cyclopentyl methyl ether (mass ratio 1:1) were pre-added to reactor I at a flow rate of 25 L / h. The temperature was lowered to 8°C, and the BF3 flow controller was started, setting the flow rate to 20 L / h. The reaction temperature inside the complexation reactor was maintained at 10°C, and the temperature control was stable. During the complexation process, the product density was measured every 2 hours, and the density was 1.02 g / cm³. 3Overflow into reactor II. ② Control the temperature of reactor II to 10℃ and the complexation temperature to 12℃. Start the BF3 flow controller, set the flow rate to 15L / h, turn on the stirrer, and maintain the pressure at 0.1-0.5Mpa. During the complexation process, repeat the process every 2 hours. The product density is measured to be 1.25g / cm³. 3 .

[0038] Example 4

[0039] The same complexation method as in Example 1 was used, with the following differences: ① 10 kg of complexing agent chloropropanol and cyclohexyl ethyl ether (mass ratio 7:1) were pre-added to reactor I at a flow rate of 28 L / h. The temperature was lowered to 8°C, and the BF3 flow controller was started, setting the flow rate to 15 L / h. The reaction temperature inside the complexation reactor was maintained at 9°C, and the temperature control was stable. During the complexation process, the product density was measured every 2 hours, and the density was 1.25 g / cm³. 3 Overflow into reactor II. ② Control the temperature of reactor II to 8℃ and the complexation temperature to 10℃. Start the BF3 flow controller, set the flow rate to 5L / h, turn on the stirrer, and maintain the pressure at 0.1-0.5Mpa. During the complexation process, repeat the process every 2 hours. The product density is measured to be 1.33g / cm³. 3 .

[0040] Example 5

[0041] The same complexation method as in Example 1 was used, with the following differences: ① 10 kg of complexing agent chloropropanol and cyclohexyl ethyl ether (mass ratio of 6:1) were pre-added to reactor I at a flow rate of 34 L / h. The temperature was lowered to 9°C, and the BF3 flow controller was started, setting the flow rate to 20 L / h. The reaction temperature inside the complexation reactor was maintained at 9°C, and the temperature control was stable. During the complexation process, the product density was measured every 2 hours, and the density was 1.20 g / cm³. 3 Overflow into reactor II. ② Control the temperature of reactor II to 9℃ and the complexation temperature to 11℃. Start the BF3 flow controller, set the flow rate to 10L / h, turn on the stirrer, and maintain the pressure at 0.1-0.5Mpa. During the complexation process, repeat the process every 2 hours. The product density is measured to be 1.30g / cm³. 3 .

[0042] Example 6

[0043] The same complexation method as in Example 1 was used, with the following differences: ① 10 kg of complexing agent chloropropanol and cyclohexyl ethyl ether (mass ratio of 8:1) were pre-added to reactor I at a flow rate of 22 L / h. The temperature was lowered to 10°C, and the BF3 flow controller was started, setting the flow rate to 30 L / h. The reaction temperature inside the complexation reactor was maintained at 12°C, and the temperature control was stable. During the complexation process, the product density was measured every 2 hours, and the density was 1.22 g / cm³. 3Overflow into reactor II. ② Control the temperature of reactor II to 10℃ and the complexation temperature to 12℃. Start the BF3 flow controller, set the flow rate to 15L / h, turn on the stirrer, and maintain the pressure at 0.1-0.5Mpa. During the complexation process, repeat the process every 2 hours. The product density is measured to be 1.28g / cm³. 3 .

[0044] Comparative Example 1

[0045] After pretreatment in the reactor, a complexation reaction was carried out in a single reactor (Unit I). Other complexation conditions were similar to those in Example 1: 10 kg of the complexing agent chloropropanol and cyclopentyl methyl ether (mass ratio 10:1) were pre-added to reactor I at a flow rate of 20 L / h. The cooling system was started, and the temperature was lowered to 10°C. The BF3 flow controller was then activated, and the flow rate was set to 15 L / h. During normal complexation, the pressure inside the reactor was maintained at 0.1-0.5 MPa, the reaction temperature inside the reactor reached 22°C, and the product density was measured to be 1.24 g / cm³. 3 The product is unloaded from the production line and transferred to a product storage tank or transport tank for BF3 content analysis and performance evaluation. Complexation conditions and product performance analysis are listed in Table 1.

[0046] Comparative Example 2

[0047] The same two-reactor series complexation process as in Example 6 was adopted, except that only one complexing agent, chloropropanol, was used. The complexation reaction process was as follows: ① 10 kg of complexing agent chloropropanol and cyclohexyl ethyl ether (mass ratio of 8:1) were pre-added to reactor I at a flow rate of 22 L / h. The temperature was lowered to 10°C, and the BF3 flow controller was started and the flow rate was set to 30 L / h. The reaction temperature in the complexation reactor was maintained at 12°C. The temperature control was stable. During the complexation process, the product density was measured every 2 hours. After the same amount of complexation time, the complexation density was measured to be 1.19 g / cm³. 3 The product overflows into reactor II. ② The temperature of reactor II is controlled at 10℃, and the complexation temperature at 12℃. The BF3 flow controller is started, the flow rate is set to 15L / h, and stirring is initiated. During the complexation process, stirring is performed at a frequency of 2 hours per cycle, the same as in Example 6. After this period, the product density is measured to be 1.22 g / cm³. 3 The product is unloaded from the production line into a product storage tank or transport tank for BF3 content analysis and performance evaluation. Complexation conditions and product performance analysis are listed in Table 1.

[0048] Comparative Example 3

[0049] Similar to Example 1, except that propanol and phenylethyl ether were used as the complexing agents. The complexation conditions and product performance analysis are listed in Table 1.

[0050] Table 1. Complexation conditions and product performance analysis

[0051]

[0052] Comparing the data in Table 1, it can be seen that the catalyst products produced in Examples 1-6 have excellent performance. Taking 500ml samples of the catalysts from the examples and comparative examples and placing them below 15℃ for 45 days, the color of the products in Examples 1-6 did not change significantly before and after the placement, and the evaluation results of the catalytic performance of the products also did not change significantly, indicating that the product quality is stable. However, the color of the products in Examples 1-3 became darker, and the conversion rate of the raw materials and the content of trimer and tetramer in the products were reduced.

[0053] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a boron trifluoride complex catalyst, characterized in that, The process includes the following steps: using haloalkyl alcohols and cycloalkyl alkyl ethers as complexing agents, a complexation reaction is carried out with BF3 gas in a first reactor until the product density in the first reactor reaches 1.15~1.3 g / cm³. 3 The overflow flows into the second reactor, and BF3 is continuously introduced until the product density in the second reactor reaches 1.25~1.35 g / cm³. 3 When the time is right, a boron trifluoride complex catalyst is obtained; The haloalkyl alcohol is a C3-C5 chloroalcohol, and the cycloalkylalkyl ether is cyclopentylmethyl ether and / or cyclohexylethyl ether; During the preparation process, the reaction temperature of the first and second reaction vessels is controlled at 5~15℃; The flow rate of BF3 in the first reactor is 15~30 L / h, and the pressure is 0.1~0.5 MPa; The flow rate of BF3 in the second reactor is 5~15L / h, and the pressure is 0.1~0.5MPa.

2. The method for preparing the boron trifluoride complex catalyst according to claim 1, characterized in that, The haloalkyl alcohol is chloropropanol.

3. The method for preparing the boron trifluoride complex catalyst according to claim 1, characterized in that, The mass ratio of haloalkyl alcohols to cycloalkyl ethers is 1 to 10:

1.

4. The method for preparing the boron trifluoride complex catalyst according to claim 1, characterized in that, The mass ratio of haloalkyl alcohols to cycloalkyl ethers is 3~8:

1.

5. The method for preparing the boron trifluoride complex catalyst according to claim 1, characterized in that, The mass ratio of BF3 to complexing agent in the boron trifluoride complexing catalyst is 0.6~1:

1.

6. The method for preparing the boron trifluoride complex catalyst according to claim 1, characterized in that, The reaction temperature was controlled with an accuracy of ±2℃ during the preparation process.

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