Hydrophobic end fluorocarbon chain oxygen atom hybridization and hydrophilic end quaternization fluorocarbon surfactant as well as synthesis method and application thereof

Abstract

The invention discloses a fluorocarbon surfactant with a hydrophobic end fluorocarbon chain oxygen atom hybridization and a hydrophilic end quaternization and a synthesis method and application thereof, the fluorocarbon surfactant has a structure shown in any one of formulas (1)-(3), # imgabs0 #, n is an integer of 1-4, n1 and n2 are integers of 3-5, m1 is an integer of 2-4, m2 is an integer of 1-4, and X is Cl, Br or I. The invention further discloses a preparation method of the fluorocarbon surfactant with the hydrophobic end fluorocarbon chain oxygen atom hybridization and the hydrophilic end quaternization. At least one of the lowest surface tension or the critical micelle concentration (CMC) of the fluorocarbon surfactant disclosed by the invention is lower than that of reported PFOS products and fluorocarbon chain hybrid substitute products of PFOS such as 6: 2 FTS, Cl-PFESA and the like. The fluorocarbon surfactant disclosed by the invention is simple in synthesis method and better in surface performance, and can be widely applied to the fields of chromium electroplating fog inhibition, aqueous film-forming fire-fighting foam, fabric three-proofing, semiconductor etching and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemicals, and in particular relates to a fluorocarbon surfactant with hybridized hydrophobic-end carbon-fluorine chain oxygen atoms and quaternized hydrophilic-end oxygen atoms, as well as a synthesis method and application thereof. Background Art

[0002] Sulfonate-based fluorocarbon surfactants, due to their excellent surface properties and stability, are irreplaceable in many key applications. Perfluorooctane sulfonic acid (PFOS), once widely used, has been banned globally due to its persistent organic pollutant properties, paving the way for the development of alternatives. Current PFOS alternatives fall into two main categories: reduced carbon-fluorine chain and hybrid carbon-fluorine chain.

[0003] Among carbon-fluorine chain-reduced products, perfluorobutanesulfonic acid (PFBS) is environmentally friendly but has insufficient surface properties, failing to meet requirements such as oil repellency. Perfluorohexylsulfonic acid (PFHxS), while having performance close to that of PFOS, is also banned due to its comparable environmental toxicity and persistence. This route struggles to balance performance and environmental protection. Among carbon-fluorine chain hybrids, perfluorohexylethylsulfonate (6:2 FTS) contains a hydrogenated hybrid chain, exhibits excellent performance, is significantly less toxic than PFOS, and exhibits no significant bioaccumulation, making it suitable for high-performance applications such as firefighting foams and electroplating. However, its chemical inertness is reduced, its stability is poor, and its production cost is higher than that of PFOS. While chlorinated polyfluoroether sulfonates (Cl-PFESA / F-53B) also offer excellent performance, studies have shown that their environmental behavior and toxicity are similar to those of PFOS, and they are bioaccumulative, posing significant risks to my country's ecological environment (for example, soil concentrations in certain areas of Tianjin have exceeded those of PFOS).

[0004] In short, no alternative currently surpasses PFOS in overall performance. While shortening or modifying the fluorocarbon chain is necessary, achieving or exceeding PFOS's key properties (such as minimum surface tension and critical micelle concentration) often requires introducing hydrocarbon groups at the hydrophilic or hydrophobic ends, but this compromises chemical inertness. Therefore, achieving fundamental breakthroughs in fluorocarbon chain morphology is a key direction for future development. Summary of the Invention

[0005] The present invention aims to provide a fluorocarbon surfactant having a hydrophobic end with a carbon-fluorine chain oxygen atom hybridized and a hydrophilic end with a quaternized amine, as well as a synthesis method and application thereof. The fluorocarbon surfactant of the present invention has at least one of a minimum surface tension and a critical micelle concentration (CMC) lower than those of reported PFOS-based products, as well as carbon-fluorine chain hybrid alternatives to PFOS such as 6:2 FTS and Cl-PFESA, and exhibits superior surface properties.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions: In the first aspect, the present invention provides a fluorocarbon surfactant having a hydrophobic end carbon-fluorine chain oxygen atom hybridization and a hydrophilic end quaternization, which has a structure shown in any one of formulas (1) to (3), , wherein n is an integer of 1 to 4, n1 and n2 are integers of 3 to 5, m1 is an integer of 2 to 4, m2 is an integer of 1 to 4, and X is Cl, Br or I.

[0007] In a second aspect, the present invention provides a method for synthesizing the above-mentioned fluorocarbon surfactant: the synthesis equations of the compounds represented by formulas (1) to (3) are: .

[0008] In the above technical scheme, the specific synthesis steps of the compound represented by formula (1) are: using potassium hydroxide as a raw material and calcium hydroxide as a fluoride ion absorbent to first convert the sulfonyl fluoride group of the starting material into a potassium sulfonate group, then using tetraalkylammonium hydroxide with n=1~4 as a cation exchanger and hydrochloric acid as a base neutralizer to convert the potassium sulfonate group into a tetraalkylammonium sulfonate group, and finally achieving the synthesis of the compound represented by formula (1); or The specific synthesis steps of the compound represented by formula (1) are as follows: using tetraalkylammonium hydroxide with n=1~4 as raw material and calcium hydroxide as fluoride ion absorbent to directly convert the sulfonyl fluoride group of the starting material into a tetraalkylammonium sulfonate group.

[0009] In the above technical scheme, the synthesis of the compound represented by formula (2) and the compound represented by formula (3) both need to be carried out through two steps. The common point is that the first step is the same, both use N,N-dimethylaminoalkylamine compounds with m1=2~4 as raw materials, and use triethylamine as an acid binding agent to absorb the hydrogen fluoride produced by the reaction to form an N,N-dimethylaminoalkylsulfonamide intermediate with a hydrophobic end carbon-fluorine chain oxygen atom hybridization feature. The difference lies in the second step. The raw material for the second step of the synthesis of the compound represented by formula (2) is a halogenated alkane with m2=1~4, and the raw material for the second step of the synthesis of the compound represented by formula (3) is a sodium halogenated alkyl carboxylate with m2=1~4.

[0010] In a third aspect, the present invention provides applications of the above-mentioned fluorocarbon surfactant in chromium electroplating mist suppression, aqueous film-forming firefighting foam, fabric triple protection, and semiconductor etching.

[0011] The beneficial effects of this invention are that its fluorocarbon surfactants exhibit at least one lower minimum surface tension or critical micelle concentration (CMC) than previously reported PFOS-based products, as well as carbon-fluorine hybrid alternatives to PFOS, such as 6:2 FTS and Cl-PFESA. The fluorocarbon surfactants of this invention are simple to synthesize and exhibit superior surface properties, making them widely applicable in fields such as chromium electroplating mist suppression, aqueous film-forming firefighting foams, textile triple protection, and semiconductor etching. DETAILED DESCRIPTION

[0012] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. The present invention can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the present invention to those skilled in the art. The present invention will be limited only by the claims.

[0013] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or can be prepared by existing methods.

[0014] The present invention provides a type of fluorocarbon surfactant with a hydrophobic end fluorocarbon chain oxygen atom hybridization and a hydrophilic end quaternization. Compared with the prior art, first of all, from the perspective of molecular structure, although this type of fluorocarbon surfactant, like 6:2 FTS and Cl-PFESA, is a fluorocarbon chain hybridization type alternative to PFOS, there are obvious differences in the hydrophobic end atomic composition. The difference from 6:2 FTS is that the present invention hybridizes the fluorocarbon chain with oxygen atoms, while 6:2 FTS hybridizes the fluorocarbon chain with hydrogen atoms. The difference from Cl-PFESA is that on the one hand, the present invention only hybridizes the fluorocarbon chain with oxygen atoms, while Cl-PFESA hybridizes the fluorocarbon chain with two atoms, oxygen atoms and chlorine atoms, and the oxygen atom hybridization site of the present invention is also different from that of Cl-PFESA. In addition, from the perspective of surface properties, the present invention has also been quaternized at the hydrophilic end in order to further improve the surface properties, thereby achieving cost reduction and efficiency improvement of the fluorocarbon surfactant, while reducing its release into the environment to weaken its environmental risks.

[0015] The specific molecular structural characteristics of the fluorocarbon surfactants of the present invention with hybridized hydrophobic end carbon-fluorine chain oxygen atoms and quaternized hydrophilic end are shown below. According to the type of hydrophilic group ions, they can be divided into anionic type (1), cationic type (2) and zwitterionic type (3). These ionic types of fluorocarbon surfactants all contain quaternized functional groups.

[0016] , wherein n is an integer of 1 to 4; n1 and n2 are integers of 3 to 5; m1 is an integer of 2 to 4; m2 is an integer of 1 to 4; and X is Cl, Br or I.

[0017] The synthesis methods of the above three different ionic types of hydrophobic end carbon-fluorine chain oxygen atom hybridization and hydrophilic end quaternization fluorocarbon surfactants are shown below. Their common point is that the starting materials are all sulfonyl fluoride compounds with hydrophobic end carbon-fluorine chain oxygen atom hybridization characteristics. The synthesis routes are shown below.

[0018] There are two methods for synthesizing anionic compounds (1). The first method uses potassium hydroxide as a raw material and calcium hydroxide as a fluoride ion absorbent to first convert the sulfonyl fluoride group of the starting material into a potassium sulfonate group. Then, tetraalkylammonium hydroxide with n=1~4 is used as a cation exchanger and hydrochloric acid is used as a base neutralizer to convert the potassium sulfonate group into a tetraalkylammonium sulfonate group, ultimately achieving the synthesis of the target anionic compound (1). The second method directly uses tetraalkylammonium hydroxide with n=1~4 as a raw material and calcium hydroxide as a fluoride ion absorbent to directly convert the sulfonyl fluoride group of the starting material into a tetraalkylammonium sulfonate group. The first method has lower raw material costs, but the final product purification cost is high. The second method has a relatively higher cost and is more suitable for preparing high-purity anionic compound (1).

[0019] The synthesis of both the cationic (2) and zwitterionic (3) products requires two steps. The common point is that the first step is the same, using N,N-dimethylaminoalkylamine compounds with m1 = 2~4 as raw materials, triethylamine as an acid binder to absorb the hydrogen fluoride produced by the reaction, and forming an N,N-dimethylaminoalkylsulfonamide intermediate with the hydrophobic end carbon-fluorine chain oxygen atom hybrid characteristics described in this patent. The difference lies in the second step. The raw material for the synthesis of the target product of the cationic (2) type is a halogenated alkane with m2 = 1~4, while the raw material for the synthesis of the target product of the zwitterionic (3) type is a sodium halogenated alkyl carboxylate with m2 = 1~4.

[0020] The fluorocarbon surfactant of the present invention, which has a hybridized hydrophobic end carbon-fluorine chain oxygen atom and a quaternized hydrophilic end, has at least one of the following properties: a minimum surface tension or a critical micelle concentration (CMC) lower than that of reported PFOS products, as well as carbon-fluorine chain hybrid alternatives to PFOS such as 6:2 FTS and Cl-PFESA, indicating that the surface performance of the product of the present invention is superior.

[0021] Minimum surface tension and critical micelle concentration (CMC) are two key indicators for evaluating surfactant performance. The critical micelle concentration (CMC) refers to the lowest concentration at which a surfactant begins to form micelles. The lower the CMC, the less dosage is required to achieve optimal results, resulting in lower costs. Minimum surface tension, on the other hand, refers to the minimum surface tension reached by a surfactant at the CMC, directly reflecting its ultimate effectiveness in reducing surface / interfacial tension. This is illustrated below using specific compounds from the present invention.

[0022] As one example, the present invention synthesized an anionic fluorocarbon surfactant product characterized by an oxygen-hybridized fluorocarbon chain, with n=2, n1=n2=4, and is named 4-(perfluorobutoxy)perfluorobutanesulfonic acid tetraethylammonium. As shown in Table 1 below, while the CMC of this anionic fluorocarbon surfactant product synthesized by the present invention is slightly higher than that of PFOS-based products with the same hydrophilic group, its minimum surface tension is as low as 17.1 mN / m, significantly lower than the 21.6 mN / m of PFOS-based products. Furthermore, the CMC and minimum surface tension of this fluorocarbon surfactant product synthesized by the present invention (0.957 mmol / L and 17.1 mN / m) are both lower than those of the similar PFOS substitute, Cl-PFESA (1.4 mmol / L and 21.2 mN / m).

[0023] Table 1. Comparison of surface properties of anionic tetraalkylammonium salts As one example, the present invention synthesizes a cationic fluorocarbon surfactant product characterized by an oxygen-hybridized fluorocarbon chain, wherein n1=n2=4; m1=3; m2=1; and X is 1. The product is named N,N-trimethyl-3-[1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamidopropylammonium iodide. As shown in Table 2 below, the CMC and minimum surface tension (0.136 mmol / L and 15.6 mN / m) of this cationic fluorocarbon surfactant product synthesized by the present invention are slightly lower than those of a similar PFOS product (0.138 mmol / L and 16.2 mN / m), and significantly lower than those of a similar 6:2 FTS product (0.16 mmol / L and 22.4 mN / m). This indicates that this product synthesized by the present invention has the best surface performance among the three.

[0024] Table 2. Comparison of surface properties of cationic quaternary ammonium iodides As one example, the present invention synthesized a zwitterionic fluorocarbon surfactant characterized by oxygen-hybridized fluorocarbon chains, with n1=n2=4, m1=3, and m2=1. Its name is 2-(dimethyl[3-([1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamido)propyl]ammonium)acetate. As shown in Table 3 below, the CMC and minimum surface tension (0.0839 mmol / L and 13.4 mN / m) of this zwitterionic fluorocarbon surfactant synthesized by the present invention are significantly lower than those of the similar PFOS product (0.155 mmol / L and 17.0 mN / m) and 6:2 FTS product (0.23 mmol / L and 15.6 mN / m). This indicates that this product synthesized by the present invention has the best surface performance among the three.

[0025] Table 3. Comparison of surface properties of zwitterionic betaine Example 1: Synthesis and Surface Performance Testing of Tetraethylammonium 4-(Perfluorobutoxy)perfluorobutanesulfonate 0.143 g of calcium hydroxide (0.5 N), 15 mL of water, 3 mL of ethanol, 2.40 g of a 25% tetraethylammonium hydroxide (1.05 N) methanol solution, and 2.00 g of perfluorobutoxybutylsulfonyl fluoride (1.0 N) were weighed sequentially into a 50 mL flask and refluxed at 90°C for 4 h. Upon completion, 9 mL of ethanol was added. The calcium fluoride precipitate was removed by hot filtration, and the filtrate was dried to obtain the crude product. The crude product was dissolved in a mixture of ethyl acetate and n-hexane by heating. After cooling, the supernatant was evaporated to dryness, yielding approximately 2.29 g of tetraethylammonium 4-(perfluorobutoxy)perfluorobutanesulfonate as a white solid with a yield of approximately 92%.

[0026] Tetraethylammonium 4-(perfluorobutoxy)perfluorobutanesulfonate was prepared into aqueous solutions of varying concentrations (see Table 4 for specific concentrations). The surface tension of these solutions at 24°C was measured using a BZY-101 fully automatic surface tension meter using the platinum plate method. The tests were conducted in ascending order of concentration, with three measurements taken for each concentration and the average value calculated. After each measurement, the platinum plate was rinsed with deionized water and calibrated to a surface tension that could detect water (approximately 71.9 mN / m) before the next test. The results are shown in Table 4.

[0027] Table 4. Surface tension test of tetraethylammonium 4-(perfluorobutoxy)perfluorobutanesulfonate Example 2: Synthesis of Intermediate N-[3-(dimethylamino)propyl]-1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonamide 1.97 g (2.0 N) 3-dimethylaminopropylamine, 1.95 g (2.0 N) triethylamine, and 20 mL (20 mL) of dichloromethane were weighed into a 50 mL flask. 5.00 g (1.0 N) perfluorobutoxybutylsulfonyl fluoride was added dropwise with stirring at 0°C. After the addition was complete, the reaction was continued for 0.5 hours, then the temperature was raised to 40°C and the reaction was continued for 4 hours. After the reaction was complete, the reaction solution was recrystallized at 0°C and filtered to obtain a pale yellow solid crude product. The crude product was washed with dichloromethane three times (10 mL / wash) to obtain approximately 5.16 g of N-[3-(dimethylamino)propyl]-1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonamide as a white solid with a yield of approximately 89%.

[0028] Example 3: Synthesis and Surface Tension Measurement of N,N-Trimethyl-3-[1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamidopropylammonium iodide Weigh 1.00 g (1.0 N) of the F404 dimethylaminopropylenediamine intermediate, 0.71 g (3.0 N) of methyl iodide, and 10 mL of anhydrous tetrahydrofuran into a 50 mL flask. The reaction was incubated at 45°C for 8 h, then heated to 60°C for 4 h. Upon completion of the reaction, the solvent was removed under reduced pressure to yield a crude brown solid. The crude product was purified by column chromatography using acetone / dichloromethane (1:1) as the developing solvent. The purified product was washed with dichloromethane and then dried to yield approximately 0.952 g of the final product, N,N-trimethyl-3-[1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamidopropylammonium iodide, as a pale yellow solid, with a yield of approximately 77%.

[0029] N,N-trimethyl-3-[1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamidopropylammonium iodide samples were prepared into aqueous solutions of varying concentrations (see Table 5 for specific concentrations). The surface tension of these solutions at 24°C was measured using a BZY-101 fully automatic surface tension meter using the platinum plate method. The tests were conducted in ascending order of concentration, with three measurements taken for each concentration and the average value calculated. After each measurement, the platinum plate was rinsed with deionized water and calibrated to a surface tension that could detect water (approximately 71.9 mN / m) before the next test. The results are shown in Table 5.

[0030] Table 5. Surface tension test of N,N-trimethyl-3-[1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamidopropylammonium iodide Example 4: Synthesis and Surface Tension Measurement of 2-(Dimethyl[3-([1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamido)propyl]ammonium)acetate 2.00 g (1.0 N) of the F404 dimethylaminopropylenediamine intermediate and 10 mL of anhydrous ethanol were weighed into a 50 mL flask. 2.35 mL of a 20% aqueous solution containing 0.47 g of sodium chloroacetate was added dropwise with stirring at room temperature. After the addition was complete, a 10% sodium hydroxide solution was added dropwise to adjust the pH of the reaction solution to approximately 8. The temperature was then raised to 70°C and the reaction was allowed to proceed for 8 hours. After the reaction was complete, the solvent was removed by rotary evaporation and dried to obtain a crude pale yellow solid product. The crude product was purified by column chromatography using methanol / dichloromethane (1:1) as the developing solvent. The purified product was washed with dichloromethane and then dried to obtain approximately 1.51 g of the final pale yellow solid product, 2-(dimethyl[3-([1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamido)propyl]ammonium)acetate, with a yield of approximately 69%.

[0031] 2-(Dimethyl[3-([1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamido)propyl]ammonium)acetate was prepared into aqueous solutions of varying concentrations (see Table 6 for specific concentrations). The surface tension of these solutions at 24°C was measured using a BZY-101 fully automatic surface tension meter using the platinum plate method. The tests were conducted in ascending order of concentration, with three measurements taken for each concentration and the average value calculated. After each measurement, the platinum plate was rinsed with deionized water and calibrated to a surface tension that could detect water (approximately 71.9 mN / m) before the next test. The results are shown in Table 6.

[0032] Table 6. Surface tension test of 2-(dimethyl[3-([1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butyl]sulfonamido)propyl]ammonium)acetate Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A fluorocarbon surfactant having a hybridized hydrophobic end carbon-fluorine chain oxygen atom and a hydrophilic end quaternized, characterized by: It has a structure shown in any one of formulas (1) to (3), ， wherein n is an integer of 1 to 4, n1 and n2 are integers of 3 to 5, m1 is an integer of 2 to 4, m2 is an integer of 1 to 4, and X is Cl, Br or I.

2. The method for synthesizing the fluorocarbon surfactant according to claim 1, characterized in that: The synthesis equations of the compounds represented by formula (1)-(3) are: 。 3. The synthesis method according to claim 2, characterized in that: The specific synthesis steps of the compound represented by formula (1) are as follows: using potassium hydroxide as a raw material and calcium hydroxide as a fluoride ion absorbent to first convert the sulfonyl fluoride group of the starting material into a potassium sulfonate group, then using tetraalkylammonium hydroxide with n=1~4 as a cation exchanger and hydrochloric acid as a base neutralizer to convert the potassium sulfonate group into a tetraalkylammonium sulfonate group, and finally achieving the synthesis of the compound represented by formula (1); or The specific synthesis steps of the compound represented by formula (1) are as follows: using tetraalkylammonium hydroxide with n=1~4 as raw material and calcium hydroxide as fluoride ion absorbent to directly convert the sulfonyl fluoride group of the starting material into a tetraalkylammonium sulfonate group.

4. The synthesis method according to claim 2, characterized in that: The synthesis of the compound represented by formula (2) and the compound represented by formula (3) both requires two steps. The common point is that the first step is the same, both use N,N-dimethylaminoalkylamine compounds with m1=2~4 as raw materials, and use triethylamine as an acid binding agent to absorb the hydrogen fluoride produced by the reaction to form an N,N-dimethylaminoalkylsulfonamide intermediate with a hydrophobic end carbon-fluorine chain oxygen atom hybridization feature. The difference lies in the second step. The raw material for the second step of the synthesis of the compound represented by formula (2) is a halogenated alkane with m2=1~4, and the raw material for the second step of the synthesis of the compound represented by formula (3) is a sodium halogenated alkyl carboxylate with m2=1~4.

5. Use of the fluorocarbon surfactant according to claim 1 in chromium electroplating mist suppression, aqueous film-forming firefighting foam, fabric three-proofing and semiconductor etching.

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