Purification of functionalized perfluoropolyethers by complexation extraction
By using complexation extraction technology to separate functionalized perfluoropolyethers from non-functionalized perfluoropolyethers, the problems of low purity and yield in existing technologies have been solved, achieving efficient and low-cost separation, which is applicable to the automotive, semiconductor and aerospace industries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG UNIV
- Filing Date
- 2022-06-23
- Publication Date
- 2026-07-03
AI Technical Summary
Existing technologies struggle to efficiently separate and purify mixtures of functionalized and non-functionalized perfluoropolyethers, resulting in low product purity and yield, as well as high equipment investment and operational complexity.
A complexation extraction method is used, employing a mixed solution of amine or carboxylic acid compounds and a strongly polar protonating solvent as the complexation extractant, to separate functionalized perfluoropolyethers from non-functionalized perfluoropolyethers in a fluorinated organic solvent. After extraction equilibrium, the mixture is concentrated to obtain high-purity functionalized perfluoropolyethers.
It achieves the separation of functionalized perfluoropolyethers with high purity (≥95%) and high yield. The operation is simple, the cost is low, and it is suitable for industrial applications. The solvent can be recycled and reused.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of separation technology for perfluoropolyether mixtures, and specifically to a method for purifying functionalized perfluoropolyethers using complexation extraction. Background Technology
[0002] Perfluoropolyether (PFPE)-based compounds possess excellent antifouling, heat resistance, solvent resistance, and lubricity properties, and are commonly used in the automotive, semiconductor, and aerospace industries. PFPEs can be classified into non-functionalized and functionalized types. The former consists of PFPE chains with terminal haloalkyl groups, while the latter has PFPE chains with at least one functional group at one end. Among functionalized PFPEs, alcohols can be used as additives in magnetic media lubricants and as intermediates in the manufacture of other high-value PFPE derivatives. Carboxylic acids can serve as intermediates or additives in acrylic resins, polyurethanes, epoxy resins, polyester resins, and coatings, significantly improving the performance of these resins and forming an important class of compounds. Functionalized PFPE compounds used in these fields require high purity; however, their preparation often yields mixtures of non-functionalized PFPE and mono / bifunctionalized PFPE. The presence of non-functionalized PFPE can cause undesirable effects, such as altering the optical properties of acrylic polymers. The properties of nonfunctional PFPE and mono / bifunctional PFPE are very similar, therefore, the purification of functionalized perfluoropolyether compounds is quite challenging.
[0003] Patent WO2014067981A discloses a method for purifying perfluoropolyether compounds with carboxylic acid ester end groups using intermittent chromatography with silica gel, silicate, or activated alumina as solid supports. However, this method suffers from low yield and significant material losses. European patent EP2905298A discloses a chromatographic method for purifying carboxylic acid perfluoropolyethers using supercritical carbon dioxide as the mobile phase and silica gel as the stationary phase. However, this method has drawbacks such as high equipment investment, and the product composition contains a high content of perfluoropolyethers with single-ended carboxyl groups, while the loss of perfluoropolyethers with double-ended carboxyl groups is significant. Patent WO2018038213A discloses a method for chromatographically separating non-alcoholic perfluoropolyethers and mixtures of perfluoropolyether monohydric alcohols and dihydric alcohols, but the yield is less than 50%.
[0004] European patent EP3578585A discloses a method for purifying functionalized perfluoropolyethers using a primary amine adsorbent. However, this method involves a stirred tank operation, which not only consumes a large amount of adsorbent and is difficult to regenerate, but also operates intermittently and is not a continuous process. Patent WO2010130625A discloses a method for purifying polyol perfluoropolyether derivatives from perfluoropolyether-based mixtures by combining a chemical reaction between alcohols and aldehydes / ketones with molecular distillation. However, this method requires strict reaction conditions, involves cumbersome steps, and involves significant equipment investment.
[0005] Therefore, developing efficient methods for purifying functional perfluoropolyether compounds from mixtures containing nonfunctional, monofunctional, and difunctional perfluoropolyethers remains a significant challenge. Summary of the Invention
[0006] To address the aforementioned technical problems and shortcomings in the field, this invention provides a method for purifying functionalized perfluoropolyethers using complexation extraction, which is simple to operate, produces high-purity products with high yields, and offers stable and controllable quality.
[0007] The specific technical solution is as follows:
[0008] A method for purifying functionalized perfluoropolyethers using complex extraction includes: dissolving a mixture containing non-functionalized perfluoropolyether and functionalized perfluoropolyether in a fluorinated organic solvent to obtain a raw material solution; contacting the raw material solution with a complex extractant; after extraction equilibrium, collecting the fluorinated organic solvent phase and concentrating it to obtain non-functionalized perfluoropolyether; and collecting the complex extractant phase and concentrating it to obtain functionalized perfluoropolyether.
[0009] At least one end group of the functionalized perfluoropolyether is -COOH, -CH2OH, -CH2SH or -NH2;
[0010] The complexing extractant is a mixed solution of an amine compound and a strongly polar protonating solvent, or a mixed solution of at least one of a carboxylic acid compound and a sulfonic acid compound and a strongly polar protonating solvent.
[0011] The strongly polar protonating solvent is one or more of methanol, ethanol, ethylene glycol, isopropanol, n-butanol, and water.
[0012] Complex extraction is an extraction and separation method based on reversible complexation reactions. It boasts advantages such as high efficiency, high selectivity, relatively simple back-extraction and regeneration processes with minimal secondary pollution and low operating costs. The key to complex extraction lies in the selection of the complexing extractant; a good complexing extractant should possess high selective recognition ability for the components to be separated. Functionalized and non-functionalized perfluoropolyether compounds have very similar molecular structures and physicochemical properties, making separation challenging.
[0013] In this invention, when the functionalized perfluoropolyether has an end group of -COOH, the complexing extractant is preferably a mixed solution of an amine compound and a strongly polar protonating solvent; when the functionalized perfluoropolyether has an end group of -CH2OH, -CH2SH, or -NH2, the complexing extractant is preferably a mixed solution of at least one of a carboxylic acid compound or a sulfonic acid compound and a strongly polar protonating solvent.
[0014] Complex extraction is not determined by a single reaction mechanism. For example, the extraction of organic carboxylic acid compounds by amine extractants involves hydrogen bonding mechanisms. Therefore, complex extraction has the advantages of high selectivity, fast reaction rate, high product purity and yield. By changing the type of complex extractant and adjusting parameters such as the concentration of the complex extractant, better extraction and separation effects on different types of functional perfluoropolyether compounds can be achieved.
[0015] In a preferred embodiment, the volume percentage of the strongly polar protonating solvent in the complexing extractant is 30% to 80%.
[0016] The nonfunctionalized perfluoropolyether may conform to the structure shown in formula (A):
[0017] T 11 -R f1 -T 12 (A)
[0018] In formula (A):
[0019] T 11 T 12 Each of the following can be independently -F, -CF3, -CF2CF3, -CF2Cl, -CF2CF2Cl or C1 to C4 perfluorinated alkyl groups;
[0020] R f1 The backbone is composed of fluorinated polyether with a number average molecular weight of 300–25000, and its chemical formula is as follows:
[0021] -O(CF2O) a -(C2F4O) b -(C3F6O) c -(C4F8O) d -
[0022] Wherein: a, b, c, and d are each independently selected from integers from 0 to 300, and the sum of a, b, c, and d is greater than 2; the order of the above repeating units (CF2O), (C2F4O), (C3F6O), and (C4F8O) is arbitrary, and the repeating unit (C3F6O) includes one or more of the following structures: (CF2CF2CF2O), (CF2CF(CF3)O), and (CF(CF3)CF2O).
[0023] The functionalized perfluoropolyether may be at least one of monofunctionalized perfluoropolyether and difunctionalized perfluoropolyether;
[0024] The monofunctionalized perfluoropolyether can conform to the structure shown in formula (B):
[0025] T 21 -R f2 -T 22(B)
[0026] The difunctionalized perfluoropolyether can conform to the structure shown in formula (C):
[0027] T 31 -R f3 -T 32 (C)
[0028] In equations (B) and (C):
[0029] T 21 It is a -F, -CF3, -CF2CF3, -CF2Cl, -CF2CF2Cl or a C1 to C4 perfluorinated alkyl group;
[0030] T 22 T 31 T 32 For -CFXR m Each can be selected independently, where -CFX is -CF2-, -CF2CF2-, -CF2CH2-, or -CF2CH2CH2-, R m It can be -COOH, -CH2OH, -CH2SH or -NH2;
[0031] R f2 R f3 The backbone consists of fluorinated polyethers with a number average molecular weight of 300–25,000, each independently selected, with the following chemical formula:
[0032] -O(CF2O) a -(C2F4O) b -(C3F6O) c -(C4F8O) d -
[0033] Wherein: a, b, c, and d are each independently selected from integers from 0 to 300, and the sum of a, b, c, and d is greater than 2; the order of the above repeating units (CF2O), (C2F4O), (C3F6O), and (C4F8O) is arbitrary, and the repeating unit (C3F6O) includes one or more of the following structures: (CF2CF2CF2O), (CF2CF(CF3)O), and (CF(CF3)CF2O).
[0034] The amine compound preferably includes at least one of primary amines, secondary amines, tertiary amines, iminoureas, and metformin;
[0035]
[0036] Among them, R, R', and R" are each preferably C1 to C12 fluorine-containing or fluorine-free hydrocarbons (including alkanes, etc.).
[0037] The carboxylic acid compound preferably includes at least one of citric acid, tertiary carbonic acid, α-halo fatty acid, malonic acid, succinic acid, glycolic acid, oxalic acid, and polyacrylic acid.
[0038] The sulfonic acid compound is R. n SO2OH, where R n Preferably, it is a C1 to C12 fluorinated or non-fluorinated hydrocarbon (including alkanes, etc.).
[0039] The fluorinated organic solvent is preferably one or more of the following: saturated hydrocarbons or their halogenated derivatives containing fluorine atoms, unsaturated hydrocarbons or their halogenated derivatives containing fluorine atoms, aromatic solvents containing fluorine atoms, ethers containing fluorine atoms, ketones containing fluorine atoms, and esters containing fluorine atoms.
[0040] The total concentration of the nonfunctionalized perfluoropolyether and the functionalized perfluoropolyether in the raw material solution is preferably 10-100 mg / mL.
[0041] If the temperature is too low, the mass transfer rate between the two phases decreases, and the time required to reach extraction equilibrium is longer, which is not conducive to production operations; if the temperature is too high, it will reduce the partition coefficient and selectivity of the extraction. The extraction temperature for the method of purifying functionalized perfluoropolyethers using complex extraction is preferably 10–60°C, and more preferably 15–55°C.
[0042] The method for purifying functionalized perfluoropolyethers by complex extraction described in this invention yields functionalized perfluoropolyethers with a purity of not less than 95% obtained through concentration.
[0043] The beneficial effects of this invention are:
[0044] 1) This invention is the first to propose a technique for separating functionalized perfluoropolyether compounds and non-functionalized perfluoropolyether compounds using complexation extraction, which is easy to industrialize.
[0045] 2) Compared with existing patented technologies such as chromatographic separation, the complexation extraction separation technology used in this invention not only has high product purity (over 95%), but also high yield, high capacity and low cost.
[0046] 3) The solvent used in this invention can be recycled and reused, which can effectively reduce costs and has broad application prospects. Detailed Implementation
[0047] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.
[0048] In the following embodiments, unless otherwise specified, "%" is based on molar reference.
[0049] Example 1
[0050] A mixture containing 40% unfunctionalized perfluoropolyether and 60% carboxyl-terminated perfluoropolyether was prepared with AC-6000 (CF3CF2CF2CF2CF2CF2CH2CH3) to form a 60 mg / mL feed solution (100 mL). Then, 150 mL of a mixed solution of perfluorobutylamine and methanol (1:1 volume ratio) was added, and complexation extraction was performed at 30 °C. After extraction equilibrium, the phases were separated. The AC-6000 phase was collected, concentrated under vacuum, and dried to obtain the unfunctionalized perfluoropolyether. The methanol phase was collected, concentrated under vacuum, and dried to obtain the active perfluoropolyether carboxylic acid compound. 19 F NMR analysis showed that the purity of the perfluoropolyether carboxylic acid compound was 96%.
[0051] Example 2
[0052] A mixture containing 50% non-functionalized perfluoropolyether and 50% carboxyl-terminated perfluoropolyether was prepared with perfluorobenzene to form a feed solution with a total concentration of 35 mg / mL (150 mL). 200 mL of a 2:1 (v / v) mixture of perfluorohexyl secondary amine and n-butanol was added, and complexation extraction was performed at 25°C. After extraction equilibrium, the phases were separated, and the ethylene glycol phase was collected to obtain the enriched carboxyl-terminated perfluoropolyether active product. This product was then concentrated under vacuum and dried to obtain the active perfluoropolyether carboxylic acid compound. 19 F NMR analysis showed that the purity of the perfluoropolyether compound with carboxyl end groups was 95%.
[0053] Example 3
[0054] A mixture of 20% unfunctionalized perfluoropolyether and 80% carboxyl-terminated perfluoropolyether was prepared with hexafluoroxylene to form a feed solution with a total concentration of 180 mg / mL. 100 mL of a 2:1 (v / v) mixture of imine urea and isopropanol was added, and complexation extraction was performed at 30°C. After extraction equilibrium, the phases were separated, and the ethanol phase was collected to obtain the enriched carboxyl-terminated perfluoropolyether active product. This product was then concentrated under vacuum and dried to obtain the active perfluoropolyether carboxylic acid compound. 19 F NMR analysis showed that the purity of the perfluoropolyether compound with carboxyl end groups was 96%.
[0055] Example 4
[0056] A mixture containing 70% nonfunctionalized perfluoropolyether and 30% amino-terminated perfluoropolyether was prepared with heptafluorocyclopentane to form a feed solution with a total concentration of 85 mg / mL (100 mL). 80 mL of a 2:3 (v / v) mixture of citric acid and water was added, and complexation extraction was performed at 30°C. After extraction equilibrium, the phases were separated, and the aqueous phase was collected to obtain the enriched amino-terminated perfluoropolyether active product. This product was then concentrated under vacuum and dried to obtain the active amino-terminated perfluoropolyether compound.19 F NMR analysis showed that the purity of the perfluoropolyether compound with amino-terminated groups was 95%.
[0057] Example 5
[0058] A mixture containing 35% unfunctionalized perfluoropolyether and 65% amino-terminated perfluoropolyether was prepared with HCFC-225 (CF3CF2CHCl2) to form a feed solution with a total concentration of 80 mg / mL, comprising 120 mL. Then, 150 mL of a 1:3 (v / v) mixture of α-chlorododecanoic acid and methanol was added, and complexation extraction was performed at 30 °C. After extraction equilibrium, the phases were separated, and the methanol phase was collected to obtain the enriched amino-terminated perfluoropolyether active product. This product was then concentrated under vacuum and dried to obtain the active amino-terminated perfluoropolyether compound. 19 FNMR analysis showed that the purity of the perfluoropolyether compound with amino-terminated groups was 96%.
[0059] Example 6
[0060] A mixture containing 75% nonfunctionalized perfluoropolyether and 25% amino-terminated perfluoropolyether was prepared with perfluorobutyl ethyl ether to form a feed solution with a total concentration of 90 mg / mL (100 mL). Then, 100 mL of a 1:2 (v / v) mixture of perfluorobutylsulfonic acid and n-butanol was added, and complexation extraction was performed at 30 °C. After extraction equilibrium, the phases were separated, and the methanol phase was collected to obtain the enriched amino-terminated perfluoropolyether active product. This product was then concentrated under vacuum and dried to obtain the active amino-terminated perfluoropolyether compound. 19 F NMR analysis showed that the purity of the perfluoropolyether compound with amino-terminated groups was 96%.
[0061] Example 7
[0062] A mixture containing 80% non-functionalized perfluoropolyether and 20% hydroxyl-terminated perfluoropolyether was prepared with trichlorotrifluoroethane to form a feed solution with a total concentration of 90 mg / mL (100 mL). Then, 100 mL of a 1:1 (v / v) mixture of glycolic acid and ethanol was added, and complexation extraction was performed at 40 °C. After extraction equilibrium, the phases were separated, and the ethanol phase was collected to obtain the enriched hydroxyl-terminated perfluoropolyether active product. This product was then concentrated under vacuum and dried to obtain the active hydroxyl-terminated perfluoropolyether compound. 19 1F NMR analysis showed that the purity of the perfluoropolyether compound with hydroxyl end groups was 95%.
[0063] Example 8
[0064] A mixture containing 65% unfunctionalized perfluoropolyether and 35% perfluoropolyether with thiol-terminated groups was prepared with perfluorobutyl ethyl ether to form a feed solution with a total concentration of 80 mg / mL (100 mL). 200 mL of a 1:1 (v / v) mixture of oxalic acid and ethanol was added, and complexation extraction was performed at 40 °C. After extraction equilibrium, the phases were separated, and the ethanol phase was collected to obtain the enriched thiol-terminated perfluoropolyether active product. This product was then concentrated under vacuum and dried to obtain the active thiol-terminated perfluoropolyether compound. 19 F NMR analysis showed that the purity of the perfluoropolyether compound with thiol end groups was 95%.
[0065] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.
Claims
1. A method for purifying functionalized perfluoropolyethers using complexation extraction, characterized in that, include: A mixture containing nonfunctionalized perfluoropolyether and functionalized perfluoropolyether is dissolved in a fluorinated organic solvent to obtain a raw material solution. The raw material solution is then contacted with a complexing extractant. After extraction equilibrium is reached, the fluorinated organic solvent phase is collected and concentrated to obtain nonfunctionalized perfluoropolyether. The complexing extractant phase is then collected and concentrated to obtain functionalized perfluoropolyether. At least one end group of the functionalized perfluoropolyether is -COOH, -CH2OH, -CH2SH or -NH2; The fluorinated organic solvent is one or more of the following: saturated hydrocarbons or their halogenated derivatives containing fluorine atoms, unsaturated hydrocarbons or their halogenated derivatives containing fluorine atoms, aromatic solvents containing fluorine atoms, ethers containing fluorine atoms, ketones containing fluorine atoms, and esters containing fluorine atoms. The complexing extractant is a mixed solution of an amine compound and a strongly polar protonating solvent, or a mixed solution of at least one of a carboxylic acid compound and a sulfonic acid compound and a strongly polar protonating solvent. The strongly polar protonating solvent is one or more of methanol, ethanol, ethylene glycol, isopropanol, n-butanol, and water.
2. The method for purifying functionalized perfluoropolyethers by complex extraction according to claim 1, characterized in that, The nonfunctionalized perfluoropolyether conforms to the structure shown in formula (A): T 11 -R f1 -T 12 (A) In formula (A): T 11 T 12 Each of the following can be independently -F, -CF2Cl, -CF2CF2Cl or C1~C4 perfluorinated alkyl groups; R f1 The backbone is composed of fluorinated polyether with a number average molecular weight of 300-25000, and its chemical formula is as follows: -O(CF2O) a -(C2F4O) b -(C3F6O) c -(C4F8O) d - Where: a, b, c, and d are each independently selected from integers from 0 to 300, and the sum of a, b, c, and d is greater than 2; the order of the above repeating units (CF2O), (C2F4O), (C3F6O), and (C4F8O) is arbitrary, and the repeating unit (C3F6O) includes one or more of the following structures: (CF2CF2CF2O), (CF2CF(CF3)O), and (CF(CF3) CF2O).
3. The method for purifying functionalized perfluoropolyethers by complexation extraction according to claim 1 or 2, characterized in that, The functionalized perfluoropolyether is at least one of monofunctionalized perfluoropolyether and difunctionalized perfluoropolyether; The monofunctionalized perfluoropolyether conforms to the structure shown in formula (B): T 21 -R f2 -T 22 (B) The difunctionalized perfluoropolyether conforms to the structure shown in formula (C): T 31 -R f3 -T 32 (C) In equations (B) and (C): T 21 It is a -F, -CF2Cl, -CF2CF2Cl or a C1~C4 perfluorinated alkyl group; T 22 T 31 T 32 For -CFXR m Each can be selected independently, where -CFX is -CF2-, -CF2CF2-, -CF2CH2-, or -CF2CH2CH2-, R m It can be -COOH, -CH2OH, -CH2SH or -NH2; R f2 R f3 The backbone consists of fluorinated polyethers with a number average molecular weight of 300-25000, each independently selected, with the following chemical formula: -O(CF2O) a -(C2F4O) b -(C3F6O) c -(C4F8O) d - Where: a, b, c, and d are each independently selected from integers from 0 to 300, and the sum of a, b, c, and d is greater than 2; the order of the above repeating units (CF2O), (C2F4O), (C3F6O), and (C4F8O) is arbitrary, and the repeating unit (C3F6O) includes one or more of the following structures: (CF2CF2CF2O), (CF2CF(CF3)O), and (CF(CF3) CF2O).
4. The method for purifying functionalized perfluoropolyethers by complex extraction according to claim 1, characterized in that, The amine compounds include at least one of primary amines, secondary amines, tertiary amines, iminoureas, and metformin; Among them, R, R', and R'' are C1 to C12 hydrocarbons, either fluorine-containing or non-fluorine-containing.
5. The method for purifying functionalized perfluoropolyethers by complex extraction according to claim 1, characterized in that, The carboxylic acid compounds include at least one of citric acid, tertiary carbonic acid, α-halo fatty acids, malonic acid, succinic acid, glycolic acid, oxalic acid, and polyacrylic acid.
6. The method for purifying functionalized perfluoropolyethers by complex extraction according to claim 1, characterized in that, The sulfonic acid compound is R. n SO2OH, where R n It refers to C1 to C12 hydrocarbons, which may contain or not contain fluorine.
7. The method for purifying functionalized perfluoropolyethers by complex extraction according to claim 1, characterized in that, The total concentration of the nonfunctionalized perfluoropolyether and the functionalized perfluoropolyether in the raw material solution is 10~100 mg / mL; In the complexing extractant, the volume percentage of the strongly polar protonating solvent is 30% to 80%.
8. The method for purifying functionalized perfluoropolyethers by complex extraction according to claim 1, characterized in that, The extraction temperature is 10~60℃.
9. The method for purifying functionalized perfluoropolyethers by complex extraction according to claim 8, characterized in that, The extraction temperature is 15~55℃.
10. The method for purifying functionalized perfluoropolyethers by complex extraction according to claim 1, characterized in that, The purity of the functionalized perfluoropolyether obtained by concentration is not less than 95%.