An extractant and method for extracting and separating boron trifluoride complex from a crude polyolefin product

Abstract

The present application relates to a kind of extractant and method for extracting and separating boron trifluoride complex in polyolefin crude product, the extractant is composed of polyhydroxy alcohol ether and chlorinated polyhydroxy alcohol, using the synergistic effect of polyhydroxy alcohol ether and chlorinated polyhydroxy alcohol, so that it obtains higher demulsification capacity to boron trifluoride complex, realizes the efficient separation of boron trifluoride complex in polyolefin crude product, so as to obtain high-quality polyolefin product.

Description

Technical Field

[0001] This invention relates to the field of boron trifluoride complex-catalyzed olefin polymerization reactions, and particularly to an extractant and method for extracting and separating boron trifluoride complexes from crude polyolefin products. Background Technology

[0002] Boron trifluoride complexes are generally prepared by complexing BF3 with cationic substances such as alcohols, aldehydes, acids, esters, and ethers at room temperature. Boron trifluoride complexes are widely used as catalysts in important organic chemical reactions such as catalysis, polymerization, and disproportionation due to their high catalytic activity and good product selectivity. However, the process of using boron trifluoride complexes to catalyze the polymerization of α-olefins to prepare PAO base oil suffers from problems such as difficult catalyst separation, easy pipeline blockage, and severe equipment corrosion. Therefore, developing a deep removal process for boron trifluoride complexes with mild conditions, short process flow, and fewer side reactions is of great significance.

[0003] US762185B2 discloses a distillation-phase separation process for boron trifluoride. After polymerization, the crude product is complexed with ethanol / acetic acid and then fed into a vacuum distillation column for cracking. The top of the column contains free boron trifluoride produced during catalyst cracking, organic matter, and unpolymerized hydrocarbons. The boron trifluoride complex generated in the condenser enters a phase separator, and the separated boron trifluoride complex is returned to the reactor for recovery. The drawbacks of this technology are its long process flow, cumbersome operation, severe corrosion problems caused by high temperatures, and poor product quality.

[0004] US6939943B2 discloses a method for extracting and separating boron trifluoride complexes. A certain amount of methanol or ethanol extractant is added to crude polyisobutylene products rich in boron trifluoride complexes at a low temperature of -60 to 20°C, causing the boron trifluoride complexes to transfer from the oil phase to the methanol or ethanol extraction phase, thus separating the boron trifluoride complexes from the product. However, this method has the drawback of low extraction rate, with a maximum of only 73%, making it unable to completely remove the boron trifluoride complexes from the crude product.

[0005] US7235509B2 discloses a method for extracting and separating boron trifluoride complexes. In this method, a fluoroalkane extractant is mixed with the crude product from a polymerization reaction at a low temperature of -30 to 10°C. After thorough stirring, the extract phase is separated from the crude product by static sedimentation. The content of boron trifluoride complexes in the extract phase is determined by gas chromatography. Although the extraction rate is greater than 90%, this method has the disadvantage of requiring a large amount of extractant, typically 1.1 times the product mass ratio, making it unsuitable for large-scale production.

[0006] CN111072821A provides a method for removing boron trifluoride and / or its complexes by extracting and separating boron trifluoride and its complexes from a fluid using a polar organic solvent. The polar organic solvent used includes one or more of sulfone compounds, oxygen-containing polyhydroxy compounds, and nitrogen-containing compounds. The organic extractant involved in this invention has limited separation efficiency for boron trifluoride and its complexes, with a maximum separation efficiency of 95%.

[0007] As can be seen from the above, the current process for preparing polyolefins by boron trifluoride-catalyzed α-olefin polymerization has problems such as severe equipment corrosion and incomplete separation of boron trifluoride complexes. Summary of the Invention

[0008] Based on the above, the main objective of this invention is to provide an extractant and method for extracting and separating boron trifluoride complexes from crude polyolefin products. Using this extractant to extract and separate boron trifluoride complexes from crude polyolefin products can effectively reduce the content of boron trifluoride complexes in the product, reduce side reactions, reduce equipment corrosion, achieve deep removal of boron trifluoride complexes, and improve product quality.

[0009] To achieve the above objectives, the present invention provides an extractant for extracting and separating boron trifluoride complexes from crude polyolefin products, wherein the extractant is composed of polyhydroxy alcohol ethers and chlorinated polyhydroxy alcohols.

[0010] Specifically, the polyhydroxy alcohol ether-chlorinated polyhydroxy alcohol composite extractant provided by the present invention utilizes the synergistic effect of polyhydroxy alcohol ether and chlorinated polyhydroxy alcohol to enable the extractant to achieve a higher demulsification ability for boron trifluoride complexes. Combined with subsequent stirring, sedimentation, separation and other steps, it achieves efficient separation of boron trifluoride complexes from crude polyolefin products, thereby obtaining high-quality polyolefin products.

[0011] Optionally, in the extractant, the content of the polyhydroxy alcohol ether is 60-85 wt%, preferably 70-85 wt%, and the content of the chlorinated polyhydroxy alcohol is 15-40 wt%, preferably 15-30 wt%.

[0012] Optionally, the polyhydroxy alcohol ether includes one or more of ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, and glycerol ether.

[0013] Optionally, the chlorinated polyhydroxy alcohol includes one or more of 3-chloro-1,2-propanediol, (S)-4-chloro-1,3-butanediol, 2-chloro-1,3-butanediol, and DL-1,4-dichloro-2,3-butanediol.

[0014] The present invention also provides a method for extracting and separating boron trifluoride complexes from crude polyolefin products, comprising the following steps: adding the above-mentioned extractant to a nonpolar fluid containing at least one boron trifluoride complex, stirring, settling, and then separating the boron trifluoride complexes from the nonpolar fluid; wherein the boron trifluoride complexes are composed of boron trifluoride and oxygen-containing organic compounds that can donate protons, preferably, the oxygen-containing organic compounds are one or more of alcohols, aldehydes, acids, esters, and ethers.

[0015] Optionally, the operating temperature of the method for extracting and separating boron trifluoride complexes from crude polyolefin products is 0–80°C, preferably 20–40°C.

[0016] Optionally, the stirring time is 0.5 to 10 hours, preferably 0.5 to 3 hours.

[0017] Optionally, the settling time is 1 to 20 hours, preferably 1 to 5 hours.

[0018] Optionally, the amount of the extractant is 1 to 20 wt% of the non-polar fluid, preferably 5 to 15 wt%.

[0019] Optionally, the non-polar fluid includes one or more of the following: crude polymeric α-olefin base oil, crude polybutene, and crude polyisobutylene. The content of boron trifluoride complex in the non-polar fluid is 0.1–1.5 wt%, preferably 0.3–0.5 wt%.

[0020] The beneficial effects of this invention are as follows:

[0021] (1) In the extractant provided by the present invention, the polyhydroxy alcohol ether and the chlorinated polyhydroxy alcohol have a synergistic effect, thereby the resulting composite extractant has a larger separation coefficient for boron trifluoride, and the composite extractant has a greater extraction rate than any component of the extractant.

[0022] (2) The extraction method provided by the present invention has a short process and is easy to operate. The amount of polyhydroxy alcohol ether-chlorinated polyhydroxy alcohol complex extractant is low, the removal rate of boron trifluoride complex is above 95%, and the content of boron trifluoride complex in the purified product is below 150 ppm. Attached Figure Description

[0023] Figure 1 This is a comparison chart of the content of boron trifluoride-butyl ether complex in polyolefins before and after extraction in Example 4. Detailed Implementation

[0024] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0025] Raw materials: Low viscosity (2-10 cSt) PAO base oil crude product; Specifications: Industrial grade; Boron trifluoride complex content 0.1-1.5 wt%; Manufacturers: Lanzhou Lubricating Oil and Additives Company, Daqing Jiatong Lubricating Oil Production Company, Daqing Petrochemical Company.

[0026] Evaluation and analysis method: Chromatographic analysis of boron trifluoride complex.

[0027] Example 1

[0028] At 25°C, 30g of a composite extractant consisting of ethylene glycol monobutyl ether and DL-1,4-dichloro-2,3-butanediol was added to 200g of low-viscosity PAO base oil crude product rich in 3300ppm boron trifluoride-butanol complex. The amount of ethylene glycol monobutyl ether added was 24.81g, and the amount of DL-1,4-dichloro-2,3-butanediol added was 5.19g. After stirring for 0.5h and allowing to settle for 3h, the raffinate phase was separated to obtain purified PAO base oil product. A small amount of the purified PAO base oil product was subjected to chromatographic analysis, which determined that the boron trifluoride complex content in the purified PAO base oil product was 130ppm. The removal rate of the boron trifluoride-butanol complex was calculated to be 96.06wt%.

[0029] Comparative Example 1-1

[0030] The only difference from Example 1 is that the composite extractant consisting of 30g of ethylene glycol monobutyl ether and DL-1,4-dichloro-2,3-butanediol used in Example 1 was replaced with 30g of ethylene glycol monobutyl ether as the extractant. After extraction, chromatographic analysis of the PAO base oil showed that the purified product contained 436ppm of boron trifluoride-butanol complex, indicating a removal rate of 86.79% for the boron trifluoride-butanol complex using this extractant.

[0031] Comparative Examples 1-2

[0032] The only difference from Example 1 is that the composite extractant consisting of 30g of ethylene glycol monobutyl ether and DL-1,4-dichloro-2,3-butanediol used in Example 1 was replaced with 30g of DL-1,4-dichloro-2,3-butanediol as the extractant. After extraction, chromatographic analysis of the PAO base oil showed that the purified product contained 53ppm of boron trifluoride-butanol complex, indicating a removal rate of 83.67% for the boron trifluoride-butanol complex using this extractant.

[0033] Comparative Examples 1-3

[0034] The only difference from Example 1 is that the composite extractant consisting of 30g of ethylene glycol monobutyl ether and DL-1,4-dichloro-2,3-butanediol used in Example 1 was replaced with an extractant consisting of 24.81g of ethylene glycol monobutyl ether and 5.19g of ethanol. The amount of ethylene glycol monobutyl ether added was 24.81g, and the amount of ethanol added was 5.19g. After extraction, chromatographic analysis of the PAO base oil showed that the content of boron trifluoride-butanol complex in the purified product was 320ppm, indicating that the removal rate of boron trifluoride-butanol complex using this extractant was 89.7%.

[0035] Comparative Examples 1-4

[0036] The only difference from Example 1 is that the composite extractant consisting of 30g of ethylene glycol monobutyl ether and DL-1,4-dichloro-2,3-butanediol used in Example 1 was replaced with a composite extractant consisting of 24.81g of DL-1,4-dichloro-2,3-butanediol and 5.19g of diethyl ether. After extraction, the PAO base oil was analyzed by chromatography, and the content of boron trifluoride-butanol complex in the purified product was 380ppm. The removal rate of boron trifluoride-butanol complex using this extractant was 88.48%.

[0037] Example 2

[0038] At 30°C, 50g of a complex extractant consisting of glycerol ether and 3-chloro-1,2-propanediol was added to 400g of crude low-viscosity PAO base oil containing 5000ppm boron trifluoride-butanol complex. The amount of glycerol ether added was 41.04g, and the amount of 3-chloro-1,2-propanediol added was 8.96g. After stirring for 3h and allowing to settle for 2h, the raffinate phase was separated to obtain purified PAO base oil product. A small amount of the purified PAO base oil product was taken for chromatographic analysis, and the content of boron trifluoride-butanol complex in the purified PAO base oil product was determined to be 137ppm. The removal rate of boron trifluoride-butanol complex was calculated to be 97.26wt%.

[0039] Comparative Example 2-1

[0040] The only difference from Example 2 is that the composite extractant consisting of 50g of ethylene glycol monobutyl ether and DL-1,4-dichloro-2,3-butanediol used in Example 2 was replaced with 50g of glycerol ether as the extractant. After extraction, chromatographic analysis of the PAO base oil showed that the content of the boron trifluoride-butanol complex was 722ppm, and the removal rate of the boron trifluoride-butanol complex using this extractant was 85.56%.

[0041] Comparative Example 2-2

[0042] The only difference from Example 2 is that the 50g of compound extractant used in Example 2 was replaced with 50g of 3-chloro-1,2-propanediol as the extractant. After extraction, the PAO base oil was analyzed by chromatography, and the content of boron trifluoride-butanol complex in the purified product was 764ppm. The removal rate of boron trifluoride-butanol complex using this extractant was 84.72%.

[0043] Comparative Examples 2-3

[0044] The only difference from Example 2 is that the 50g of the composite extractant used in Example 2 was replaced with 41.04g of glycerol ether and 8.96g of ethanol extractant. The purified product contained 624ppm of boron trifluoride-butanol complex, and the removal rate of boron trifluoride-butanol complex using this extractant was 87.52%.

[0045] Comparative Examples 2-4

[0046] The only difference from Example 2 is that the 50g composite extractant used in Example 2 was replaced with an extractant composed of 41.04g of 3-chloro-1,2-propanediol and 8.96g of acetone. The purified product contained 724ppm of boron trifluoride-butanol complex, and the removal rate of boron trifluoride-butanol complex using this extractant was 85.52%.

[0047] Example 3:

[0048] At 50°C, 10g of a composite extractant consisting of ethylene glycol methyl ether and 2-chloro-1,3-butanediol was added to 100g of crude low-viscosity PAO base oil containing 4500ppm boron trifluoride-methanol complex. The amount of ethylene glycol methyl ether added was 7.25g, and the amount of 2-chloro-1,3-butanediol added was 2.75g. After stirring for 4h and allowing to settle for 5h, the extract phase and raffinate phase were separated to obtain a purified product. A small amount of the purified product was subjected to chromatographic analysis, which determined that the boron trifluoride complex content in the purified product was 120ppm. Calculations showed that the removal rate of the boron trifluoride-methanol complex was 97.33wt%.

[0049] Comparative Example 3-1

[0050] The only difference from Example 3 is that the 10g of the composite extractant in Example 3 was replaced with 10g of ethylene glycol methyl ether as the extractant. The purified product contained 614 ppm of boron trifluoride-methanol complex, and the removal rate of boron trifluoride-methanol complex using this extractant was 86.36%.

[0051] Comparative Example 3-2

[0052] The only difference from Example 3 is that the 10g of the composite extractant in Example 3 was replaced with 2-chloro-1,3-butanediol as the extractant. The purified product contained 731ppm of boron trifluoride-methanol complex, and the removal rate of boron trifluoride-methanol complex using this extractant was 83.76%.

[0053] Comparative Example 3-3

[0054] The only difference from Example 3 is that the 10g composite extractant in Example 3 was replaced with an extractant composed of 7.25g ethylene glycol methyl ether and 2.75g ethanol, while the amounts of each component remained unchanged. The purified product contained 552ppm of boron trifluoride-methanol complex, and the removal rate of boron trifluoride-methanol complex using this extractant was 87.73%.

[0055] Comparative Examples 3-4

[0056] The only difference from Example 3 is that the 10g of the composite extractant in Example 3 was replaced with an extractant composed of 7.25g of 2-chloro-1,3-butanediol and 2.75g of acetone. The purified product contained 330ppm of boron trifluoride-methanol complex, and the removal rate of boron trifluoride-methanol complex using this extractant was 86.80%.

[0057] Example 4:

[0058] At 40℃, 15g of a composite extractant consisting of ethylene glycol monobutyl ether and DL-1,4-dichloro-2,3-butanediol was added to 150g of crude polybutene product rich in 2500ppm boron trifluoride-butyl ether complex. The amount of ethylene glycol monobutyl ether added was 10.15g, and the amount of DL-1,4-dichloro-2,3-butanediol added was 4.85g. After stirring for 1.5h and allowing to settle for 3h, the raffinate phase was separated to obtain the purified product. A small amount of the purified product was taken for chromatographic analysis (the comparison of the boron trifluoride-butyl ether complex content in polybutene before and after extraction is shown in the figure). Figure 1 As shown in the figure, the content of boron trifluoride complex in the purified product was determined to be 120 ppm. After conversion, the removal rate of boron trifluoride-butyl ether complex was 95.20 wt%.

[0059] Comparative Example 4-1

[0060] The only difference from Example 4 is that the 15g of composite extractant used in Example 4 was replaced with 15g of ethylene glycol monobutyl ether as the extractant. The purified product contained 334ppm of boron trifluoride-butyl ether complex, and the removal rate of boron trifluoride-butyl ether complex using this extractant was 86.64%.

[0061] Comparative Example 4-2

[0062] The difference from Example 4 is that the 15g of composite extractant used in Example 4 was replaced with 15g of DL-1,4-dichloro-2,3-butanediol as the extractant. The purified product contained 479ppm of boron trifluoride-butyl ether complex, and the removal rate of boron trifluoride-butyl ether complex using this extractant was 80.84%.

[0063] Comparative Example 4-3

[0064] The only difference from Example 4 is that the 15g of the composite extractant used in Example 4 was replaced with an extractant composed of 10.15g of ethylene glycol monobutyl ether and 4.85g of ethanol. The purified product contained 197ppm of boron trifluoride-butyl ether complex, and the removal rate of boron trifluoride-butyl ether complex using this extractant was 92.12%.

[0065] Comparative Example 4-4

[0066] The only difference from Example 4 is that the 15g of the composite extractant used in Example 4 was replaced with an extractant composed of 10.15g of DL-1,4-dichloro-2,3-butanediol and 4.85g of acetone. The purified product contained 282ppm of boron trifluoride-butyl ether complex, and the removal rate of boron trifluoride-butyl ether complex using this extractant was 88.72%.

[0067] Example 5:

[0068] At 60℃, 20g of a composite extractant consisting of ethylene glycol monobutyl ether and (S)-4-chloro-1,3-butanediol was added to 250g of crude polybutene product rich in 10000ppm boron trifluoride-butyl ether complex. The amount of ethylene glycol monobutyl ether added was 16.15g, and the amount of (S)-4-chloro-1,3-butanediol added was 3.85g. After stirring for 1.5h and allowing to settle for 3h, the extract phase and raffinate phase were separated to obtain a purified product. Chromatographic analysis showed that the boron trifluoride complex content in the purified product was 148ppm, and the removal rate of the boron trifluoride complex was calculated to be 98.52wt%.

[0069] Comparative Example 5-1

[0070] The only difference from Example 5 is that the 20g of composite extractant used in Example 5 was replaced with 20g of ethylene glycol monobutyl ether as the extractant. The purified product contained 1432ppm of boron trifluoride-butyl ether complex, and the removal rate of boron trifluoride-butyl ether complex using this extractant was 85.68%.

[0071] Comparative Example 5-2

[0072] The only difference from Example 5 is that the 20g of the composite extractant used in Example 5 was replaced with 20g of (S)-4-chloro-1,3-butanediol as the extractant. The purified product contained 1932ppm of boron trifluoride-butyl ether complex, and the removal rate of boron trifluoride-butyl ether complex using this extractant was 80.68%.

[0073] Comparative Example 5-3

[0074] The only difference from Example 5 is that the 20g composite extractant used in Example 5 was replaced with an extractant composed of 16.15g ethylene glycol monobutyl ether and 3.85g ethanol. The purified product contained 1268ppm of boron trifluoride-butyl ether complex, and the removal rate of boron trifluoride-butyl ether complex using this extractant was 87.32%.

[0075] Comparative Example 5-4

[0076] The only difference from Example 5 is that the 20g composite extractant used in Example 5 was replaced with an extractant composed of 16.15g of (S)-4-chloro-1,3-butanediol and 3.85g of acetone. The purified product contained 1386ppm of boron trifluoride-butyl ether complex, and the removal rate of boron trifluoride-butyl ether complex using this extractant was 86.14%.

[0077] In summary, the extractant provided by this invention exhibits a synergistic effect between polyhydroxy alcohol ethers and chlorinated polyhydroxy alcohols, resulting in a composite extractant with a large separation coefficient for boron trifluoride. This allows the composite extractant to achieve a higher extraction rate compared to any single component of the extractant. The extraction method provided by this invention has a short process, is easy to operate, requires a low dosage of the polyhydroxy alcohol ether-chlorinated polyhydroxy alcohol composite extractant, achieves a boron trifluoride complex removal rate of over 95%, and yields a purified product with a boron trifluoride complex content below 150 ppm.

[0078] 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 present invention.

Claims

1. An extractant for extracting and separating boron trifluoride complexes from crude polyolefin products, characterized in that, The extractant is composed of polyhydroxy alcohol ethers and chlorinated polyhydroxy alcohols; In the extractant, the content of the polyhydroxy alcohol ether is 60-85 wt%, and the content of the chlorinated polyhydroxy alcohol is 15-40 wt%.

2. The extractant according to claim 1, characterized in that, In the extractant, the content of the polyhydroxy alcohol ether is 70-85 wt%.

3. The extractant according to claim 1, characterized in that, The polyhydroxy alcohol ethers include one or more of ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, and glycerol ether.

4. The extractant according to claim 1, characterized in that, The chlorinated polyhydroxy alcohol includes one or more of 3-chloro-1,2-propanediol, (S)-4-chloro-1,3-butanediol, 2-chloro-1,3-butanediol, and DL-1,4-dichloro-2,3-butanediol.

5. The extractant according to claim 1, characterized in that, In the extractant, the content of the chlorinated polyhydroxy alcohol is 15-30 wt%.

6. A method for extracting and separating boron trifluoride complexes from crude polyolefin products, characterized in that, Includes the following steps: The extractant according to any one of claims 1 to 5 is added to a nonpolar fluid containing at least one boron trifluoride complex, stirred, allowed to settle, and then the boron trifluoride complex in the nonpolar fluid is separated; the boron trifluoride complex is composed of boron trifluoride and an oxygen-containing organic compound that can donate protons.

7. The method according to claim 6, characterized in that, The operating temperature of the method for extracting and separating boron trifluoride complexes from crude polyolefin products is 0–80°C.

8. The method according to claim 6, characterized in that, The stirring time is 0.5 to 10 hours.

9. The method according to claim 6, characterized in that, The settling time is 1 to 20 hours.

10. The method according to claim 6, characterized in that, The amount of the extractant used is 1 to 20 wt% of the non-polar fluid.

11. The method according to claim 6, characterized in that, The non-polar fluid includes one or more of the following: crude polymeric α-olefin base oil, crude polybutene, and crude polyisobutylene, and the content of boron trifluoride complex in the non-polar fluid is 0.1 to 1.5 wt%.

12. The method according to claim 6, characterized in that, The oxygen-containing organic compounds are one or more of the following: alcohols, aldehydes, acids, esters, and ethers.

13. The method according to claim 7, characterized in that, The method for extracting and separating boron trifluoride complexes from crude polyolefin products operates at a temperature of 20–40°C.

14. The method according to claim 8, characterized in that, The stirring time is 0.5 to 3 hours.

15. The method according to claim 9, characterized in that, The settling time is 1 to 5 hours.

16. The method according to claim 10, characterized in that, The amount of the extractant used is 5 to 15 wt% of the non-polar fluid.

17. The method according to claim 11, characterized in that, The content of boron trifluoride complex in the nonpolar fluid is 0.3-0.5 wt%.

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