Degradable surfactant and preparation method thereof

Abstract

In order to overcome the problem that the substitutes of the existing C8 fluorine surfactants cannot simultaneously consider degradability and surface activity, the application provides a degradable surfactant, which comprises the following structure: wherein R1 is selected from a perfluoroalkyl group with 2-7 carbon atoms or an oxafuorine chain, R2 is selected from a hydrogen atom or a carbon-hydrogen alkyl chain with 1-6 carbon atoms, n is an integer of 1-5, R3 and R4 are selected from a hydrogen atom or a carbon-hydrogen alkyl chain with 1-3 carbon atoms, R5 is selected from -CH2-, -CH2CH2-, -CH2CH2CH2- or -CH2CH(OH)CH2-, and A is selected from -CO2 or -SO3.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluorine-containing surfactants, and particularly relates to a degradable surfactant and a preparation method thereof. BACKGROUND

[0002] Due to the unique properties of fluorine atoms, fluorine-containing compounds have been widely used in the fields of medicine, pesticides and materials. Similar to surfactants, fluorine surfactants are also composed of hydrophilic heads and hydrophobic tails [Langmuir 2015, 31, 8205-8217.]. In structure, the hydrophobic tail of fluorine surfactants is composed of perfluoro or polyfluoro substituted carbon chains. Compared with other types of surfactants, fluorine surfactants have the characteristics of water and oil repellency, high stability, high surface activity and low dosage [Fluorinated Surfactants and Repellents. Marcel Dekker, Inc.: New York, 2001.]. However, due to its high cost, fluorine surfactants are often used in specific applications or added in compounding to obtain excellent surface activity at a lower dosage.

[0003] At the end of the 21st century, many ecological environment studies also showed that perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) and their derivatives (fluorine functional group carbon atom number greater than or equal to 8, commonly known as C8, sometimes also collectively referred to as PFOX) exhibit persistence, bioaccumulation, toxicity and long-distance migration ability to the environment and organisms [Environ. Sci. Technol. 1999, 33, 2800-2806.; Environ. Sci. Technol. 2000, 34, 3864-3870.]. With the listing of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in the appendix of persistent organic pollutants (POPs) of the Stockholm Convention in 2009 and 2019, people gradually realized the harm of C8 fluorine surfactants containing long perfluoroalkyl chains. On October 11, 2021, the Ministry of Ecological Environment of China released the “New Pollutant Control Action Plan (Draft for Comments)”, which mentioned that by the end of 2025, the production and processing use of PFOS and PFOA compounds will be strictly limited.

[0004] To address the environmental concerns of the previous C8 fluorosurfactants, the current replacement strategies mainly focus on the introduction of shorter per(poly)fluorocarbon chains and oxygenated perfluorinated chains [Curr. Opin. Colloid. Interface. Sci. 2015, 20, 192-212.; Trends Environ. Anal. Chem. 2019, 23, e00066.; Science 2022, 375, eabg9065].

[0005] The purpose of using shorter per(poly)fluorocarbon chains (sulfonic carbon number ≤ 5, carboxylic carbon number ≤ 7) is to reduce the number of fluorocarbon, weaken its environmental persistence and biological toxicity. However, due to the polarization of fluorocarbon bonds is much weaker than that of carbon-hydrogen bonds, the degree of reduction of fluorination under the same carbon number may cause great changes in its physical and chemical properties, that is, the decrease of surface activity and the increase of critical micelle concentration [Langmuir 2006, 22, 4643-4648.]

[0006] Another alternative strategy is to introduce oxygen atoms into the fluorocarbon segment, which not only increases the hydrophobic segment while maintaining the number of fluorocarbons, but also regulates the biological toxicity and degradability of the surfactant molecule by introducing oxygen atoms [Curr. Opin. Colloid. Interface. Sci. 2015, 20, 192-212.]. However, due to the specific way of introducing oxygen-containing segments, the diversity of fluorine ether segments is limited [Chemosphere 2015, 129, 4-19.], and it is difficult to regulate toxicity and biological accumulation. Moreover, the degradation ability of fluorine ether segments in the natural environment is not as expected, and the toxicity of various aspects may be similar to that of the original long-chain perfluoroalkyl substances, which still has the potential to become a persistent pollutant [Environ. Int. 2015, 75, 172-179. Environ. Sci. Technol. Lett. 2019, 6, 662-668.]. For example, hexafluoropropylene oxide trimer acid (HFPO-TA), although its surface activity can be compared with traditional C8 surfactants, HFPO-TA also shows environmental problems that cannot be ignored - wide environmental distribution, similar biological accumulation to PFOA, more intense cytotoxicity, hepatotoxicity and stronger endocrine disrupting effects [Environ. Sci. Technol. 2020, 54, 13389-13398. J. Hazard. Mater. 2020, 389, 122124. Organic Fluorine Industry 2021, (04), 31-38.]. In order to alleviate such environmental problems, many fluorinated chemical companies choose short-chain fluorine ether substitutes. Although the environmental effects of these products are somewhat milder than traditional fluorinated surfactants, the surface activity of these products at similar concentrations is much lower than that of traditional fluorinated surfactants, and the amount used to achieve the same effect is higher than before, the cost of substitution increases sharply, and there is also the possibility of falling back into the "lock-in" effect.

[0007] In the face of environmental persistence, biological accumulation and toxicity brought about by traditional surfactants, existing substitutes have proposed solutions, but have not been able to satisfactorily solve the contradiction between the environment and performance. Therefore, designing an environmentally friendly, excellent surface active molecular structure is the key to breaking the vicious cycle of "lock-in" effect. SUMMARY

[0008] In view of the problem that the existing substitutes for fluorinated surfactants cannot balance degradability and surface activity, the present application provides a degradable surfactant and a preparation method thereof.

[0009] The technical scheme adopted by the present application to solve the above technical problems is as follows:

[0010] In one aspect, the present application provides a degradable surfactant comprising the following structure:

[0011]

[0012] wherein R1 is selected from a perfluoroalkyl group having 2 to 7 carbon atoms or an oxaf luoro chain, R2 is selected from a hydrogen atom or a carbon-hydrogen alkyl chain having 1 to 6 carbon atoms, n is an integer from 1 to 5, R3 and R4 are each independently selected from a hydrogen atom or a carbon-hydrogen alkyl chain having 1 to 3 carbon atoms, R5 is selected from -CH2-, -CH2CH2-, -CH2CH2CH2- or -CH2CH(OH)CH2-, and A is selected from -CO2 or -SO3.

[0013] Optionally, R1 is selected from a perfluoroalkyl group having 2 to 5 carbon atoms or an oxaf luoro chain having 2 to 5 carbon atoms.

[0014] Optionally, R1 is selected from CF3CF2-, CF3CF2CF2-, CF3CF2CF2CF2-, CF3CF2CF2CF2CF2-, CF3OCF(CF3)-, CF3CF2OCF2-, CF3CF2CF2OCF2-, CF3OCF2CF2-, CF3OCF2OCF2-, CF3(OCF2)2OCF2-, CF3(OCF2)3OCF2-, CF3CF2OCF(CF3)-, CF3CF2OCF2CF2-, CF3(CF2)2OCF(CF3)-, and CF3(CF2)2OCF2CF2-.

[0015] Optionally, R1 is selected from CF3(CF2) m OCF(CF3)-, and m = 0, 1 or 2.

[0016] Optionally, R2 is selected from a hydrogen atom or a carbon-hydrogen alkyl chain having 1 to 3 carbon atoms.

[0017] Optionally, R2 is selected from H or CH3-.

[0018] Optionally, n = 2 or 3.

[0019] Optionally, R3 and R4 are selected from CH3-.

[0020] Optionally, R5 is selected from -CH2- or -CH2CH2-.

[0021] Optionally, A is selected from -CO2.

[0022] Optionally, one or more of the following compounds:

[0023]

[0024] In another aspect, the present application provides a method for preparing the degradable surfactant as described above, comprising the following steps:

[0025]

[0026] wherein R1 is selected from a perfluoroalkyl group having 2-7 carbon atoms or an oxafurine chain;

[0027] The sulfuryl chloride compound shown in structural formula 2 is obtained, and the sulfuryl chloride compound shown in structural formula 2 is used as a reaction precursor to prepare a tertiary amine through amidation, and then converted into betaine to prepare the compound shown in structural formula 1.

[0028] Optionally, the sulfuryl chloride compound shown in structural formula 2 is prepared by the following method:

[0029]

[0030] The sulfuryl chloride compound shown in structural formula 2 is obtained by chlorinating the thiocyanate compound shown in structural formula 3 with chlorine or sulfuryl chloride.

[0031] Optionally, the thiocyanate compound shown in structural formula 3 is prepared by the following method:

[0032]

[0033]

[0034] The iodo compound shown in structural formula 4 is obtained, and the iodo compound shown in structural formula 4 is reacted with potassium thiocyanate to obtain the thiocyanate compound shown in structural formula 3.

[0035] Optionally, the iodo compound shown in structural formula 4 is prepared by the following method:

[0036]

[0037] The iodo compound shown in structural formula 5 is obtained, and the iodo compound shown in structural formula 5 is subjected to an addition reaction with ethylene to obtain the iodo compound shown in structural formula 4.

[0038] Optionally, the iodo compound shown in structural formula 5 is prepared by the following method:

[0039]

[0040] The acyl fluoride shown in structural formula 6 is obtained, and the acyl fluoride shown in structural formula 6 is reacted with iodine in the presence of sodium carbonate to obtain the iodo compound shown in structural formula 5 through distillation and purification.

[0041] Optionally, the operation of "preparing tertiary amine through amidation, and then converting into betaine" comprises:

[0042]

[0043] In the presence of triethylamine, the sulfonyl chloride compound shown in structural formula 2 is reacted with the compound shown in structural formula 7 to obtain the fluoroether ethyl sulfonamide shown in structural formula 8.

[0044] The fluoroether ethyl sulfonamide shown in structural formula 8 is reacted with the compound shown in structural formula 9 to obtain the betaine shown in structural formula 10.

[0045] Next, the degradability of the degradable surfactant is described.

[0046] As persistent organic pollutants, traditional fluorinated surfactants can only degrade non-fluorine groups in the environment, and the degradation products are mostly perfluoroalkyl carboxylic acids, and the length of the fluorocarbon chain is basically unchanged. Due to the stability of the fluorocarbon bond, perfluoroalkyl carboxylic acid is often difficult to further degrade in the environment. The industry urgently needs to develop a degradable fluorinated surfactant, which requires that the degradation product is no longer a long-chain perfluoroalkyl carboxylic acid or a fluoroether alkyl carboxylic acid, and can be deeply degraded in the environment to obtain a shorter chain molecule, that is, by improving the degradability to weaken the potential of persistent organic pollutants of the parent molecule.

[0047] Therefore, we envisage that if a new molecule is cleverly designed to be functionally similar to a long-chain molecule with high surface activity, and then the new molecule is like a "multi-stage rocket", it is degraded and falls off into a short-chain molecule, and is environmentally compatible (such as Figure 2 ). The solution to achieve this path is to place an oxygen atom at a suitable position of the fluoroether chain segment to form a degradation switch, synthesize a degradable fluoroether surfactant, and thus reduce the impact of fluorinated surfactants on the ecology, and solve the contradiction between the performance of the surfactant and the environment.

[0048] The degradable surfactant provided by the application is provided with a branched fluoroether ethylene structure (i.e. -OCF(CF3)CH2CH2-) between the fluorine chain / oxygen-fluorine chain and the hydrophilic group. Through the preset photodegradation experiment, it is found that the betaine with such a structure can be degraded under relatively mild conditions, and the degradation product is a short-chain fluoroether carboxylic acid, which has good degradability. In the comparative experiment, it is found that the comparative analog with a straight-chain structure (i.e. -OCF2CF2CH2CH2-) can only be degraded to obtain a long-chain fluoroether carboxylic acid. Therefore, the degradation performance of the compound with the structural characteristics of the patent is better than that of the comparative analog, that is, the compound molecule with the structure of the patent has a unique degradability. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 is a surface tension test chart of various zwitterionic surfactants provided by the present application;

[0050] Figure 2 is a degradation principle comparison chart of existing fluorinated surfactants and the degradable surfactants provided by the present application. DETAILED DESCRIPTION

[0051] In order to make the technical problems solved by the present application, technical solutions and beneficial effects more clearly understood, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0052] The present application provides a degradable surfactant, comprising the following structure:

[0053]

[0054] wherein R1 is selected from a perfluoroalkyl group having 2-7 carbon atoms or an oxafurane chain, R2 is selected from a hydrogen atom or a carbon-hydrogen alkyl chain having 1-6 carbon atoms, n is an integer of 1-5, R3 and R4 are each independently selected from a hydrogen atom or a carbon-hydrogen alkyl chain having 1-3 carbon atoms, R5 is selected from -CH2-, -CH2CH2-, -CH2CH2CH2- or -CH2CH(OH)CH2-, and A is selected from -CO2 or -SO3.

[0055] In some embodiments, R1 is selected from a perfluoroalkyl group having 2-5 carbon atoms or an oxafurane chain having 2-5 carbon atoms.

[0056] In some embodiments, R1 is selected from CF3CF2-, CF3CF2CF2-, CF3CF2CF2CF2-, CF3CF2CF2CF2CF2-, CF3OCF(CF3)-, CF3CF2OCF2-, CF3CF2CF2OCF2-, CF3OCF2CF2-, CF3OCF2OCF2-, CF3(OCF2)2OCF2-, CF3(OCF2)3OCF2-, CF3CF2OCF(CF3)-, CF3CF2OCF2CF2-, CF3(CF2)2OCF(CF3)- or CF3(CF2)2OCF2CF2-.

[0057] In some embodiments, R1 is selected from CF3(CF2) m OCF(CF3)-, m = 0, 1 or 2.

[0058] In some embodiments, R2 is selected from a hydrogen atom or a carbon-hydrogen alkyl chain having 1-3 carbon atoms.

[0059] In some embodiments, R2 is selected from H or CH3-.

[0060] In some embodiments, n = 2, 3.

[0061] In some embodiments, R3, R4 is selected from CH3-.

[0062] In some embodiments, R5 is selected from -CH2- or -CH2CH2-.

[0063] In some embodiments, A is selected from -CO2.

[0064] In some embodiments, the degradable surfactant is selected from one or more of the following compounds:

[0065]

[0066] It should be noted that the above are only part of the embodiments claimed by the present application, and should not be understood as a limitation of the present application.

[0067] Embodiments of the present application provide a method for preparing the degradable surfactant as described above, comprising the following operation steps:

[0068]

[0069] Obtain a sulfonyl chloride compound as shown in structural formula 2, and use the sulfonyl chloride compound as shown in structural formula 2 as a reaction precursor to prepare a tertiary amine through amidation, and then convert it into betaine to prepare the compound as shown in structural formula 1.

[0070] In some embodiments, the sulfonyl chloride compound as shown in structural formula 2 is prepared by the following method:

[0071]

[0072] Obtain a thiocyanate compound as shown in structural formula 3, and perform chlorination on the thiocyanate compound as shown in structural formula 3 by using chlorine gas or thionyl chloride to obtain the sulfonyl chloride compound as shown in structural formula 2.

[0073] In specific embodiments, taking R1 selected from CF3CF2CF2OCF(CF3)- as an example, the preparation process of the sulfonyl chloride compound as shown in structural formula 2 is described:

[0074] Method one:

[0075] Into a pressure vessel was added CF3CF2CF2OCF(CF3)CF2OCF(CF3)CH2CH2SCN, acetic acid and nitrogen was heated to 45-50°C. Chlorine was continuously bubbled into the mixture for 10 hours. Simultaneously, water was continuously added to the mixture for 8 hours. After that, the reaction was stirred at 45-50°C for 1 hour. At 45-50°C, chlorine was added for the second time for 2.5 hours and stirring was continued for 1 hour. The crude product was heated to 70°C and washed with deionized water. The organic layer was separated in a glass separatory funnel, added to toluene, washed with 3.5 wt% sodium chloride solution twice, and after removing the excess solvent, the product 5b was obtained.

[0076]

[0077] Method Two: R F = CF3CF2CF2OCF(CF3)CF2OCF(CF3)-

[0078] Into a 100 mL three necked flask equipped with magnetic stirring, two stopcocks and a ball jointed reflux condenser was added acetic acid as solvent and C922-SCN (4b). The reaction system required a silicon tube attached to the outside of the ball jointed reflux condenser to bubble the possible gas into a 250 mL three necked flask (the other two ports were capped with stopcocks and the other was connected with a silicon tube to a 250 mL conical flask) which was used as a buffer flask to prevent back suction. The 250 mL conical flask was filled with 10 wt% KOH to absorb the possible acidic materials. Then using a 10 mL syringe, sulfuryl chloride was added dropwise into the stirred mixture from one of the stopcocks, and using a 1 mL syringe, water was added dropwise into the three necked flask from the other stopcock. At this time, the liquid mixture in the three necked flask turned light yellow and refluxed with heat, and bubbles were continuously generated in the KOH solution. Then the mixture was heated to 50°C and reacted for 18 hours. After the reaction was completed, the mixture was cooled to room temperature, and then about 10 mL of water was added into the three necked flask using a 10 mL syringe to quench the residual sulfuryl chloride in the mixture. The liquid mixture turned bright red first and then light yellow after the water was added, and the generated gas was absorbed by the KOH solution. After the quenching was completed, the stopcocks and the ball jointed reflux condenser were opened, and the mixture was left to air blow in the fume hood for 5 minutes to remove the possible chlorine or hydrogen chloride. Then the mixture was transferred into a 250 mL separatory funnel, dichloromethane was added, and the mixture was shaken and allowed to stand for 3 minutes. Then the lower organic phase was removed. Dichloromethane was added to extract the water layer three more times. The organic phases were collected, and since the product might react with the filter paper, the water was not removed, and the solvent was removed using a rotary evaporator. Then the light yellow liquid was evaporated using an oil pump with a cold trap, and the light yellow liquid was weighed. The light yellow liquid 5b was obtained.

[0079] In some embodiments, the thiocyanate compound of structural formula 3 is prepared by the following method:

[0080]

[0081]

[0082] The iodide of structural formula 4 is obtained, and the iodide of structural formula 4 is reacted with potassium thiocyanate to obtain the thiocyanate compound of structural formula 3.

[0083] In specific embodiments, the preparation of the thiocyanate compound of structural formula 3 is described with R1selected from CF3CF2CF2OCF(CF3)- as an example:

[0084]

[0085] R F = CF3CF2CF2OCF(CF3)CF2OCF(CF3)-

[0086] Into a 250 mL round bottom flask equipped with a spherical condenser and magnetic stirring, C922-I (3a), potassium thiocyanate and a stir bar were added. Ethanol and acetic acid were added as solvents, where ethanol was used to dissolve the substrate and acetic acid was used to dissolve the potassium thiocyanate. The reaction mixture was heated to 80 °C and the reaction time was 18 hours. The solid-liquid mixture of the reaction was observed to change from colorless at the beginning to orange-red and finally to orange-yellow, with a lot of fine salt analysis. The solid-liquid mixture obtained from the reaction was first transferred to a 250 mL separatory funnel, saturated brine was added, shaken three times and allowed to separate for 3 minutes. After standing, the lower organic phase was separated. Dichloromethane was added to extract three times and the lower organic phase was collected. The organic phases were combined, anhydrous sodium sulfate was used to remove water, and then the salt was filtered out and the filtrate was collected. The filtrate was spin-dried in a rotary evaporator. The light yellow liquid obtained was subjected to vacuum distillation (external temperature 150 °C, internal temperature 80 °C, pressure 2 Torr) to obtain a light yellow liquid 4b.

[0087] In some embodiments, the iodide of structural formula 4 is prepared by the following method:

[0088]

[0089] The iodide of structural formula 5 is obtained, and the iodide of structural formula 5 is subjected to addition reaction with ethylene to obtain the iodide of structural formula 4.

[0090] In specific embodiments, the preparation of the iodide of structural formula 4 is described with R1selected from CF3CF2CF2OCF(CF3)- as an example:

[0091]

[0092] R F =CF3CF2CF2OCF(CF3)CF2OCF(CF3)-

[0093] C92-I (2b) and recrystallized dibenzoyl peroxide (BPO) and a stir bar were added to a 100 mL autoclave (material: stainless steel 316L) equipped with a pressure gauge, a pressure relief valve, and a magnetic stirrer. Then, the operation of vacuuming three times and filling nitrogen was performed. Ethylene was filled into the autoclave, and the pressure relief valve was closed. Then, the autoclave was placed in an oil bath, the oil bath was heated to 80°C, and the reaction was performed for 6 hours. The reading of the pressure gauge decreased from 0.9 MPa at room temperature to 0.25 MPa (room temperature), which indicated that the free radical addition reaction occurred, and part of the ethylene was consumed. After the reaction was completed, the autoclave in the oil bath was cooled to room temperature. The autoclave was opened, and the colorless liquid (with a sweet ethylene odor) obtained by the reaction was collected. The reaction obtained liquid 3b was a colorless liquid. Finally, the product was subjected to vacuum distillation, the internal temperature of the distillation was 72°C, the external temperature was 130°C, and the pressure was tested by using a mercury pressure gauge after the distillation system was stabilized. The pressure of the vacuum distillation was 5 kPa (about 37 Torr).

[0094] In this preparation process, C92-I (2b) was washed with sodium thiosulfate first. The washed 2b can effectively improve the conversion rate of 2b to 3b. This may be due to the fact that part of the substrate contains a small amount of solvent DME which is not completely washed clean. For a free radical reaction, the ether solvent may block it, so the preset deiodination free radical addition reaction cannot proceed. After sufficient washing, 2b can be obtained with a high conversion rate.

[0095] In some embodiments, the iodide of structural formula 5 is prepared by the following method:

[0096]

[0097] The acyl fluoride of structural formula 6 is obtained, and the acyl fluoride of structural formula 6 is reacted with iodine in the presence of sodium carbonate to obtain the iodide of structural formula 5.

[0098] In specific embodiments, the preparation process of the iodide of structural formula 5 is described by taking R1 selected from CF3CF2CF2OCF(CF3)- as an example:

[0099]

[0100] R F= CF3CF2CF2OCF(CF3)CF2OCF(CF3)-

[0101] Into a 1 L three-necked flask equipped with a mechanical stirrer and a reflux condenser was added sodium carbonate, iodine and anhydrous DME and heated to 40 °C using a heating mantle. At 40 °C, C92-COF (1b) was added dropwise to the stirred mixture via a dropping funnel (about 2 hours for the addition). After the addition was complete, the reaction mixture was gradually warmed to 80 °C (5 °C every 5 minutes) and reacted for 18 hours. At the end of the reaction, the mixture was cooled to room temperature and transferred to a 500 mL Erlenmeyer flask for distillation, resulting in a brownish red liquid (the distillation was incomplete due to the high boiling point of C92-I (2b), and the distillation temperature was high). After washing with saturated brine and a small amount of 1 wt% sodium thiosulfate solution (to remove elemental iodine), the mixture was separated using a 250 mL separatory funnel, and after shaking three times, the original brownish red color was observed to change to colorless. After standing for 2 minutes, the lower organic phase (light purple) was removed. Dichloromethane was added to the aqueous phase and extracted three times. After the extraction was complete, the organic phases were combined and dried using anhydrous sodium sulfate. After filtering off the salt using filter paper, the filtrate was rotary evaporated to obtain a light purple liquid, and C92-I (2b) was obtained after rectification.

[0102] In some embodiments, the "preparing a tertiary amine via amidation, and converting to a betaine" operation comprises:

[0103]

[0104]

[0105] In the presence of triethylamine, a sulfonyl chloride compound shown in structural formula 2 is reacted with a compound shown in structural formula 7 to obtain a fluoroether ethyl sulfonamide shown in structural formula 8;

[0106] The fluoroether ethyl sulfonamide shown in structural formula 8 is reacted with a compound shown in structural formula 9 to obtain a betaine shown in structural formula 10.

[0107] In specific embodiments, the preparation of the betaine shown in structural formula 10 is described with R1 selected from CF3CF2CF2OCF(CF3)CF2- as an example:

[0108]

[0109] R F = CF3CF2CF2OCF(CF3)CF2OCF(CF3)-

[0110] Dimethylaminopropylamine, triethylamine and anhydrous methyl tert-butyl ether (MTBE) were charged into a 100 mL three-necked round bottom flask equipped with a reflux condenser, magnetic stirrer and temperature probe. C922-SO2Cl (5b) was then added dropwise into the stirred mixture using a 1 mL syringe. A significant amount of white smoke was observed to be generated, which was continuously absorbed as the stirring proceeded, and the liquid mixture in the flask became a white turbid solid-liquid mixture. The mixture was then heated to reflux and reacted for 24 hours. After the reaction was completed, the reaction flask was cooled to room temperature to obtain a white solid-liquid mixture, which was transferred to a 250 mL separatory funnel and introduced with another 15 mL of water and 20 mL of dichloromethane, and repeatedly shaken and settled. After 3 minutes of settling, the lower organic phase was removed. Dichloromethane was added for extraction three more times, and the organic phases were collected, and anhydrous sodium sulfate was added for dehydration (in the form of a flowing sand, not lumped), and then the salt was filtered using a funnel, and the filtrate was collected. The solvent was then spin-dried on a rotary evaporator to obtain an amber liquid 6b.

[0111]

[0112] R F = CF3CF2CF2OCF(CF3)CF2OCF(CF3)-

[0113] C922S-Amine (6b), ethanol, deionized water, sodium chloroacetate and sodium bicarbonate were charged into a 50 mL three-necked round bottom flask equipped with a reflux condenser, magnetic stirrer and temperature probe. The reaction mixture was heated to 80°C and reacted for 6 hours. After the reaction was completed, the obtained solid-liquid mixture was spin-dried in a rotary evaporator to obtain a white solid 7b.

[0114] It should be noted that when R1 is selected from other groups defined in the present application, the preparation process of the degradable surfactant is similar to the above preparation process, which will not be described here.

[0115] Compared with other existing substitutes for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) Capstone 1157 (the main fluorine surfactant of which is C62S-Betaine of Comparative Example 1 of the present patent), the present degradable surfactant has a branched fluoroether ethylene structure (-OCF(CF3)CH2CH2-) between the fluorine chain / oxyfluorine chain and the hydrophilic group. It is found through degradation experiments that it has good degradability and can be degraded under relatively mild conditions, thereby having a lower environmental and biological accumulation effect. At the same time, the degradable surfactant also has excellent surface activity and a lower critical micelle concentration, and its performance is similar to that of the existing substitutes.

[0116] The present application will be further described below through examples.

[0117] Example 1

[0118] This example is used to illustrate the C722S-Betaine (7a) (2-(dimethyl(3-((3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)butyl)sulfonamido)propyl)ammonio)acetate) and its preparation method disclosed by the present application, including the following operation steps:

[0119] 1) Preparation of C72-I (2a)

[0120]

[0121] To a 1 L three-necked flask equipped with mechanical stirring and reflux condenser, add sodium carbonate (58.4 g, 550 mmol, 1.1 equiv.), iodine (140 g, 550 mmol, 1.1 equiv.) and anhydrous DME (200 mL), and heat to 40 °C using a heating mantle. At 40 °C, C72-COF (1a) (200 g, 500 mmol, 1 equiv.) is added dropwise to the stirred mixture through a dropping funnel (about 30 minutes for dropwise addition). After dropwise addition is complete, the reaction mixture is gradually warmed to 80 °C (5 °C per 10 minutes), and reacted for 8 hours. At the end of the reaction, the mixture is cooled to room temperature, transferred to a 500 mL flask for distillation, and a brownish red liquid is obtained. After washing with 100 mL of saturated brine and adding a small amount of 1 wt% sodium thiosulfate solution (to remove elemental iodine), the mixture is separated using a 250 mL separatory funnel, shaken three times, and the original brownish red color is observed to change to colorless. After standing for 2 minutes, the lower organic phase (light purple) is removed. Another 30 mL of dichloromethane is added to the aqueous phase to extract three times. After the extraction is complete, the organic phases are combined and dried using anhydrous sodium sulfate. After filtering off the salt using filter paper, the filtrate is rotary evaporated to obtain a light purple liquid 214 g, which is subjected to 19 F-NMR detection found that C72-I: C72-H = 74:26, iodine head selectivity was 74%, the yield of the crude product was 89%, and the actual yield of 2a was 66%.

[0122] The crude products collected from the two reactions were concentrated and distilled, yielding a total of 382g (with similar selectivity across batches). At the beginning of the distillation process, the reflux valve should be closed while the upper gas valve is open. Once the thermometer reading at the top of the column stabilizes at 60-65℃ (outer temperature 125℃), the reflux valve is opened to allow liquid to flow out; this is the light component liquid. Once the liquid stops flowing back and the thermometer reading drops below 40℃, the reflux valve is closed, and reflux is restarted. When the thermometer reading rises again and stabilizes at 98℃ (outer temperature 150℃), the reflux valve is reopened to allow liquid to flow out continuously; this is the heavy component. The distillation operation is stopped when no more liquid flows out from the top of the column. After weighing, a total of 160g of the light component liquid was obtained, which was a colorless liquid. The heavy component liquid weighed 197g, which was a dark purple liquid. Some bottom liquid remained undistilled. 19 F-NMR and 1 H-NMR analysis confirmed that the light component consisted of approximately 90% C72-H and 10% solvent DME, while the recombinant component was C72-I (pale purple liquid, 197 g, 0.42 mol) with a purity exceeding 95%.

[0123] C72-I(2a) 19 The results of F-NMR, IR, and HRMS detections are as follows:

[0124]

[0125] 1,1,1,2,3,3-Hexafluoro-3-(1,2,2,2-tetrafluoro-1-iodoethoxy)-2-(trifluoromethoxy)propane

[0126] 1,1,1,2,3,3-Hexafluoro-3-(1,2,2,2-tetrafluoro-1-iodoethoxy)-2-(trifluorometh-oxy)propane(2a): Pale purple liquid, yield 66%. Bp: 96-99℃. 19 F NMR(376MHz, CDCl3)δ-53.5(m,3F),-75.6(m,1F),-79.9(m,3F),-80.6–-81.2(m,1F),-84.1(m,3F),-88.1–-88.7(m,1F),-146.7(m,1F).IR(film)ν / cm -1 :1231,1158,1077,982,922,893,805,773,740,685,666,616,535.HRMS-FI(m / z):calcd for C6O2F 13 [MI] +350.9685; found: 350.9689.

[0127] Table 1. Distillation process data for 2a

[0128]

[0129] 2) Preparation of C722-I(3a)

[0130]

[0131] C72-I(2a) (32.6 g, 68 mmol, 1 equiv.) and recrystallized BPO (200 mg, 0.8 mmol, 0.12 equiv.) and a stir bar were added to a 100 mL autoclave (made of 316L stainless steel) equipped with a pressure gauge, a pressure reducing valve, and a magnetic stirrer. The autoclave was then evacuated three times and purged with nitrogen. Ethylene (3.5 g, 120 mmol, 1.8 equiv.) was added to the autoclave, and the pressure reducing valve was closed. The autoclave was then placed in an oil bath, heated to 80 °C, and reacted for 6 hours. The pressure gauge reading decreased from 1.2 MPa at room temperature to 0.78 MPa (room temperature), indicating that the free radical addition reaction had occurred and some ethylene had been consumed. After the reaction was complete, the autoclave was removed from the oil bath and cooled to room temperature. The autoclave was opened, and the resulting colorless liquid (with a sweet ethylene odor) was collected and weighed (33.8 g). 1 H-NMR and 19 F-NMR analysis of the colorless liquid confirmed that the liquid obtained from the reaction was 3a (colorless liquid, 33.8 g, 66.8 mmol), with a yield of 98%.

[0132] C722-I(3a) 1 H NMR, 19 The results of F-NMR, IR, and HRMS detections are as follows:

[0133]

[0134] 1,1,1,2-Tetrafluoro-2-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)-4-iodobutane

[0135] 1,1,1,2-Tetrafluoro-2-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)-4-iodobutane (3a): Colorless liquid, yield 98%. Bp 40℃ / 4 Torr. 1H NMR (400 MHz, CDC13) δ 3.17 (m, 2H), 2.79 (m, 2H). 19 F NMR (376 MHz, CDC13) δ -53.4 (m, 3F), -79.3 - -80.1 (m, 4F), -81.1 - 81.7 (m, IF), -83.0 (d, J = 9 Hz, 3F), -129.6 (m, IF), -146.0 - -146.3 (m, IF). 13 CNMR (100 MHz, CDC13) δ 38.3 (d, J = 22 Hz), -11.5, carbons corresponding to the CF3OCF(CF3)CF2OCF(CF3)-group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 1445, 1309, 1239, 1158, 1064, 1050, 982, 910, 737. HRMS-EI (m / z): calcd for C8H4O2F 13 I[M] + : 505.9043; found: 505.9049.

[0136] 3) Preparation of C722-SCN (4a)

[0137]

[0138] A 250 mL round bottom flask equipped with a magnetic stir bar was charged with C722-I (33.2 g, 66 mmol, 1 equiv.), potassium thiocyanate (12.7 g, 131 mmol, 2 equiv.) and a stir bar. Ethanol (50 mL) and acetic acid (10 mL) were added as solvents. The reaction mixture was heated to 80 °C and the reaction time was 16 hours. The reaction was observed to change from colorless to orange-red and finally to orange-yellow. A large amount of fine salt was observed. The reaction mixture was first transferred to a 250 mL separatory funnel, 50 mL of saturated brine was added, shaken three times and allowed to separate for 3 minutes. The lower organic layer was separated. The organic layer was extracted with 10 mL x 3 dichloromethane and the lower organic layer was collected. The organic layers were combined, dried over 5 g of anhydrous sodium sulfate, filtered and the filtrate was collected. The filtrate was concentrated on a rotary evaporator. The light yellow liquid was sampled and sent for GC-MS analysis. After confirming it was the product 4a, the light yellow liquid was distilled under reduced pressure (outer temperature 150 °C, inner temperature 80 °C, pressure 11 Torr) to give a light yellow liquid (26.8 g, 61.3 mmol) in 94% yield.

[0139] Synthesis of C722-SCN (4a) 1 H NMR, 19 F-NMR, 13 C NMR, IR and HRMS results are as follows:

[0140]

[0141] 1,1,1,2-Tetrafluoro-2-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)-4-thiocyanatobutane (4a): light yellow liquid in 94% yield. B.p. 81-83 °C / 11 Torr.

[0142] 1,1,1,2-Tetrafluoro-2-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)-4-thiocyanatobutane (4a): light yellow liquid in 94% yield. B.p. 81-83 °C / 11 Torr. 1 H NMR (400 MHz, CD3OD) δ 3.23 (m, 2H), 2.85 (m, 2H). 19F NMR (376 MHz, CD3OD) δ -54.9 (m, 3F), -79.8 - -80.6 (m, 1F), -81.2 (m, 3F), -82.1 - -82.7 (m, 1F), -84.5 (d, J = 10 Hz, 3F), -130.0 (m, 1F), -147.1 - -147.4 (m, 1F). 13 C NMR (100 MHz, CDC13) δ 110.3, 34.1 (d, J = 22 Hz), 25.3, carbons corresponding to the CF3OCF(CF3)CF2OCF(CF3)- group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 2162, 1443, 1239, 1077, 988, 892, 737, 685, 537. HRMS-EI (m / z): calcd for C9H4O2NF 13 S[M] + : 436.9750; found: 436.9751.

[0143] 4) Preparation of C722-SO2CI (5a)

[0144]

[0145] To a 100 mL three neck flask equipped with magnetic stirring, two septa and a ball jointed reflux condenser was added acetic acid (10 mL) as solvent and C722-SCN (4a) (2.2 g, 5 mmol). The reaction set up required a silicon tubing to be attached to the outside of the ball jointed reflux condenser to vent the gases produced into a 250 mL three neck flask (two ports capped with stoppers and one port connected to a 250 mL conical flask with silicon tubing) which acted as a buffer flask to prevent back siphoning. The 250 mL conical flask was filled with 10 wt% KOH to absorb any acidic material produced. A 10 mL syringe was then used to add sulfuryl chloride (6.7 mL, 50 mmol) drop wise into the stirred mixture from one of the septa and a 1 mL syringe was used to add water (270 mg, 15 mmol) into the three neck flask from the other septa. At this point, the liquid mixture in the three neck flask turned a light yellow color and refluxed due to the heat of reaction and bubbles were observed in the KOH solution. The mixture was then heated to 50 °C and left to react for 18 hours. After the reaction was complete, the mixture was cooled to room temperature and a 10 mL syringe was used to add approximately 10 mL of water into the three neck flask to quench any remaining sulfuryl chloride in the mixture. The liquid mixture turned a bright red color and then a light yellow color as the water was added and the gases produced were absorbed by the KOH solution. After the quench was complete, the septa and ball jointed reflux condenser were removed and the mixture was left to air blow in a fume hood for 5 minutes to remove any remaining chlorine or hydrogen chloride. The mixture was then transferred to a 250 mL separatory funnel and 10 mL of dichloromethane was added and the mixture was shaken and allowed to stand for 3 minutes. The lower organic layer was then removed and the water layer was extracted with 5 mL x 3 of dichloromethane. The organic layers were combined and the mixture was not dried as the product could react with the filter paper. The mixture was then concentrated on a rotary evaporator and the light yellow liquid was then further dried using an oil pump with a cold trap and weighed to give 2.3 g of a light yellow liquid. 19 F-NMR and 1 H-NMR were used to identify the product and the yield was 96%.

[0146] Preparation of C722-SO2Cl (5a) 1 H NMR, 19 F-NMR, 13 C NMR, IR and HRMS were used to identify the product and the yield was 96%.

[0147]

[0148] 3,4,4,4-Tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)butane-1- sulfonyl chloride

[0149] 3,4,4,4-Tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)butane- 1 -sulfonyl chloride (5a): colorless liquid, yield 96%. B.p. 85-88 °C / 1 Torr. 1 H NMR (400 MHz, CDCI3) δ 3.82 (m, 2H), 2.92 (m, 2H). 19 F NMR (376 MHz, CDCI3) δ -53.4 (m, 3F), -79.3 - -80.2 (m, 4F), -81.1 - -81.8 (m, 1 F), -83.0 (m, 3F), -129.2 (m, 1 F), -145.9 - -146.2 (m, 1 F). 13 C NMR (100 MHz, CDCI3) δ 57.1, 28.6 (d, J = 23 Hz), carbons corresponding to the CF3OCF(CF3)CF2OCF(CF3)-group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 3014, 2950. 2350, 1747, 1444, 1382, 1238, 1078, 988, 892, 764, 737, 541, 496. HRMS-EI (m / z): calcd for C8H4O4F 13 S[M-Cl] + : 442.9617; found: 442.9612.

[0150] 5) Preparation of C722S-Amine (6a)

[0151]

[0152] Dimethylaminopropylamine (918 mg, 9 mmol, 1.5 equiv.), triethylamine (1.2 g, 12 mmol, 2 equiv.) and dry MTBE (15 mL) were charged into a 100 mL three necked round bottom flask equipped with a reflux condenser, magnetic stirrer and temperature probe. C722-S02CI (5a) (1.09 g, 6 mmol, 1 equiv.) prepared using the method of Example 1 was then added dropwise into the stirred mixture using a 1 mL syringe. A significant amount of white smoke was observed to be generated and as stirring proceeded, the generated smoke was constantly absorbed and the liquid mixture in the flask turned into a white turbid solid-liquid mixture. The mixture was then heated to reflux and stirred for 24 hours. After the reaction was completed, the reaction flask was cooled to room temperature to obtain a white solid-liquid mixture which was transferred into a 250 mL separatory funnel and 15 mL of water and 20 mL of dichloromethane were introduced and the mixture was shaken repeatedly and allowed to settle. After 3 minutes, the lower organic phase was removed. The organic phase was extracted three times with 5 mL x 3 dichloromethane and the organic phases were collected and 2 g of anhydrous sodium sulfate was added to dry the salt (in the form of a flowing sand and does not cake) and the salt was filtered using a funnel and the filtrate was collected. The solvent was then spun off on a rotary evaporator to obtain 2.7 g of an amber liquid with a yield of 82%.

[0153] Preparation of C722S-Amine (6a) 1 H NMR, 19 F-NMR, 13 C NMR, IR and HRMS results are as follows:

[0154]

[0155] N-(3-(Dimethylamino)propyl)-3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)butane-1-sulfonamide

[0156] N-(3-(Dimethylamino)propyl)-3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)butane-1-sulfonamide (6a): white solid with a yield of 82%. 1 H NMR (400 MHz, CD3OD) δ 3.21 (m, 2H), 3.08 (t, J = 7.2 Hz, 2H), 2.74 (m, 2H), 2.38 (t, J = 7.6 Hz, 2H), 2.23 (s, 6H), 1.71 (m, 2H). 19F NMR (376 MHz, CD3OD) δ -54.9 (m, 3F), -79.9 - -80.8 (m, 1F), -81.2 (m, 3F), -82.2 - -82.7 (m, 1F), -84.6 (d, J = 10 Hz), -129.7 (m, 1F), -147.1 - -147.4 (m, 1F). 13 C NMR (100 MHz, CD3OD) δ 57.7, 45.4, 45.0, 42.2, 28.9, 28.8 (d, J = 23 Hz), carbons corresponding to the CF3OCF(CF3)CF2OCF(CF3)- group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 3290, 3072, 2953, 2867, 2826, 2786, 1466, 1310, 1243, 1155, 1063, 987, 892, 768, 737, 557. HRMS -ESI (m / z): calcd for C 13 H 18 O4N2F 13 S [M+H] + : 545.0785; found: 545.0784.

[0157] 6) Preparation of C722S-Betaine (7a)

[0158]

[0159] C722S-Amine (6a) (1.58 g, 3 mmol, 1 equiv.), ethanol (8 mL), deionized water (4 mL), sodium chloroacetate (348 mg, 3 mmol, 1 equiv.) and sodium bicarbonate (252 mg, 3 mmol, 1 equiv.) were added to a 50 mL three necked round bottom flask equipped with a reflux condenser, magnetic stirrer and temperature probe. The reaction mixture was heated to 80 °C for 24 hours. At the end of the reaction, the resulting solid-liquid mixture was spin dried in a rotary evaporator to obtain 1.4 g of white solid with a 77% yield.

[0160] Preparation of C722S-Betaine (7a) 1 H NMR, 19 F-NMR, 13 C NMR, IR and HRMS results are as follows:

[0161]

[0162] 2-(dimethyl(3-((3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)butyl)sulfonamido)propyl)ammonio)acetate (7a): white solid, yield 32%.

[0163] 2-(dimethyl(3-((3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)butyl)sulfonamido)propyl)ammonio)acetate (7a): white solid, yield 32%. 1 H NMR (400 MHz, CD3OD) δ 3.81 (s, 2H), 3.66 (m, 2H), 3.21 - 3.30 (m, 8H), 3.16 (m, 2H), 2.75 (m, 2H), 1.99 (m, 2H). 19 F NMR (376 MHz, CD3OD) δ -54.9 (m, 3F), -79.8 - -80.7 (m, IF), -81.2 (m, 3F), -82.2 - -82.8 (m, IF), -84.5 (d, J = 10 Hz, 3F), -129.5 - -129.8 (m, IF), -147.1 - -147.4 (m, IF). 13 C NMR (100 MHz, CD3OD) δ 168.9, 65.1, 63.2, 51.9, 45.0, 41.0, 28.7 (d, J = 23 Hz), 25.0, carbons corresponding to the CF3OCF(CF3)CF2OCF(CF3)- group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 3444, 2106, 1632, 1484, 1400, 1313, 1235, 1156, 1076, 988, 893, 738, 686, 555. HRMS-DART (m / z): calcd for C 15 H 20 O6N2F 13 S [M+H] + : 603.8929; found: 603.0828.

[0164] Example 2

[0165] This embodiment illustrates the C922S-Betaine(7b)(2-(dimethyl(3-((3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)butyl)sulfonamide)propyl)ammonium)acetic acid inner salt) disclosed in this invention and its preparation method, including the following steps:

[0166] 1) Preparation of C92-I(2b)

[0167]

[0168] Sodium carbonate (47 g, 440 mmol, 1.1 equiv.), iodine (112 g, 440 mmol, 1.1 equiv.), and anhydrous DME (200 mL) were added to a 1 L three-necked flask equipped with a mechanical stirrer and a reflux condenser, and the mixture was heated to 40 °C using a heating mantle. At 40 °C, C92-COF(1b) (200 g, 400 mmol, 1 equiv.) was added dropwise to the stirred mixture through a dropping funnel (the addition took approximately 2 hours). After the addition was complete, the reaction mixture was gradually heated to 80 °C (5 °C every 5 minutes), and the reaction was allowed to proceed for 18 hours. After the reaction was complete, the mixture was cooled to room temperature and transferred to a 500 mL round-bottom flask for distillation, yielding a brownish-red liquid (due to the high boiling point of C92-I and the high distillation temperature, the distillation was incomplete). After washing with 100 mL of saturated saline solution and a small amount of 1 wt% sodium thiosulfate solution (excluding iodine), the mixture was separated using a 250 mL separatory funnel. After shaking three times, the original brownish-red color changed to colorless. After standing for 2 minutes, the lower organic phase (light purple) was collected. Then, 30 mL of dichloromethane was added to the aqueous phase for extraction three times. After extraction, the organic phases were combined and dried over anhydrous sodium sulfate. The salts were filtered off using filter paper, and the filtrate was evaporated to dryness on a rotary evaporator, yielding 162 g of a light purple liquid. This liquid was then distilled to obtain approximately 140 g of C92-I(2b), with a yield of 61%.

[0169] C92-I(2b) 19 The results of F NMR, IR and HRMS detection are as follows:

[0170]

[0171] 1,1,1,2,2,3,3-Hepanofluoro-3-((1,1,1,2,3,3-Hexafluoro-3-(1,2,2,2-Tetrafluoro-1-iodoethoxy)propane-2-yl)oxy)propane

[0172] 1,1,1,2,2,3,3-Heptafluoro-3-((1,1,1,2,3,3-hexafluoro-3-(1,2,2,2-tetrafluoro-1- iodoe thoxy)propan-2-yl)oxy)propane (2b): pale purple liquid, yield 61%. B.p. 140 °C / 37 Torr. 19 F NMR (376 MHz, CDC13) δ -75.4 - -75.7 (m, IF), -79.9 (m, 3F), -80.8 - -82.3 (m, 6F), -84.1 (m, 3F), -88.0 - -88.9 (m, IF), -129.7 (m, 2F), -145.7 (m, IF). IR (film) v / cm-1: 3445, 1790, 1298, 1235, 1200, 1098, 994, 923, 907, 804, 747, 707, 667, 650, 534. HRMS-EI (m / z): calcd for C8O2F -1 : 450.9621; found: 450.9627. 17 [M-I] + : 450.9621; found: 450.9627.

[0173] 2) Preparation of C922-I (3b)

[0174]

[0175] C92-I (2b) (30.0 g, 52 mmol, 1 equiv.) and recrystallized BPO (100 mg, 0.4 mmol, 0.8 mol%) and a stirring bar were introduced into a 100 mL autoclave (material: stainless steel 316L) equipped with a pressure gauge, a pressure relief valve and magnetic stirring. Three vacuum-pumping and nitrogen-filling operations were then performed. Ethylene (3.5 g, 120 mmol, 1.8 equiv.) was introduced into the autoclave and the pressure relief valve was closed. The autoclave was then placed in an oil bath, which was heated to 80 °C, and the reaction was carried out for 6 hours. The pressure gauge reading decreased from 0.9 MPa at room temperature to 0.25 MPa at room temperature, which indicated that the radical addition reaction had occurred and some of the ethylene had been consumed. At the end of the reaction, the autoclave was removed from the oil bath and cooled to room temperature. The autoclave was opened and the colorless liquid (with a sweet ethylene odor) obtained in the reaction was collected and weighed at 27.6 g. The product was purified by distillation under reduced pressure (bath temperature: 130 °C, pressure: 37 Torr) and the colorless liquid (with a sweet ethylene odor) obtained in the reaction was collected and weighed at 24.6 g. The product was analyzed by H-NMR and 1 H-NMR and 19F NMR analysis of the colorless liquid confirmed that the liquid obtained from the reaction was 3b (colorless liquid, 27.6 g, 45.5 mmol) with a yield of 88%. The product was also subjected to a vacuum distillation with an internal temperature of 72 °C, an external temperature of 130 °C, and a pressure of 5 kPa (about 37 Torr) as measured by a mercury manometer after the distillation system was stabilized.

[0176] C922-I (3b) was synthesized according to the following scheme: 1 H NMR, 19 F NMR, 13 C NMR, IR and HRMS results are as follows:

[0177]

[0178] 1,1,1,2-Tetrafluoro-2-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)-4-iodobutane (3b): colorless liquid, yield 88%. B.p. 72 °C / 37 Torr.

[0179] 1,1,1,2-Tetrafluoro-2-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)-4-iodobutane (3b): colorless liquid, yield 88%. B.p. 72 °C / 37 Torr. 1 H NMR (400 MHz, CDC13) δ 3.17 (d, J = 8.8 Hz, 2H), 2.78 (m, 2H). 19 F NMR (376 MHz, CDC13) δ -79.1 - -80.4 (m, 4F), -80.2 - -82.6 (m, 6F), -83.2 (m, 3F), -88.1 - -88.9 (m, IF), -145.5 (t, J = 22 Hz, 2F), -145.8 (m, IF). 13 C NMR (100 MHz, CD3OD) δ 38.8 (d, J = 22 Hz), -12.3, carbons corresponding to the CF3CF2CF2OCF(CF3)CF2OCF(CF3)- group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 1446, 1307, 1239, 1200, 1158, 1049, 1064, 994, 909, 809, 747, 706, 650, 583, 535. HRMS-EI (m / z): calcd for C 10 H4O2F 17I[M] + :605.8979; found:605.8978.

[0180] 3) Preparation of C922-SCN(4b)

[0181]

[0182] C922-I(3b) (5 g, 8 mmol, 1 equiv.), potassium thiocyanate (1.55 g, 16 mmol, 2 equiv.), and a stir bar were added to a 250 mL round-bottom flask equipped with a spherical condenser and a magnetic stirrer. Ethanol (10 mL) and acetic acid (1 mL) were added as solvents. The reaction mixture was heated to 80 °C and reacted for 16 hours. The solid-liquid mixture was observed to gradually change from colorless to orange-red, finally settling at an orange-yellow color, with many fine salts precipitated. The resulting solid-liquid mixture was first transferred to a 250 mL separatory funnel, 20 mL of saturated saline solution was added, the mixture was shaken three times, and allowed to stand for 3 minutes for separation. After standing, the lower organic phase was separated. Then, 5 mL × 3 of dichloromethane was added for extraction three times, and the mixture was separated, collecting the lower organic phase. The organic phases were combined, and water was removed using 2 g of anhydrous sodium sulfate. The salts were then filtered off, and the filtrate was collected. The solvent in the filtrate was evaporated using a rotary evaporator. The resulting pale yellow liquid was then sampled and analyzed by GC-MS. After confirming that it was product 4b, the pale yellow liquid was subjected to vacuum distillation (external temperature 150℃, internal temperature 80℃, pressure 2 Torr) to obtain 3.2 g (6.0 mmol) of pale yellow liquid, with a yield of 74%.

[0183] C922-SCN(4b) 1 H NMR, 19 F NMR, 13 The results of C NMR, IR and HRMS detection are as follows:

[0184]

[0185] 1,1,1,2-Tetrafluoro-2-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)-4-thiocyanate butane

[0186] 1,1,1,2-Tetrafluoro-2-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)-4-thiocyanatobutane (4b): Orange-yellow liquid, yield 74%. Bp 80℃ / 2 Torr. 1H NMR (400 MHz, CD3OD) δ 3.21 (d, J = 8.0 Hz, 2H), 2.85 (m, 2H). 19 F NMR (376 MHz, CD3OD) δ -79.7 - -80.8 (m, IF), -81.4 (m, 3F), -82.3 - -84.0 (m, 6F), -84.6 (m, 3F), -130.0 (m, IF), -131.0 (m, 2F), -146.2 (m, IF). 13 C NMR (100 MHz, CD3OD) δ 112.3, 34.6 (d, J = 22 Hz), 26.6 carbons corresponding to the CF3CF2CF2OCF(CF3)CF2OCF(CF3)-group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 2162, 1444, 1333, 1305, 1239, 1075, 993, 947, 810, 747, 706, 687, 650, 535, 458. HRMS-EI (m / z): calcd for C 11 H4O2NF 17 S[M] + : 536.9686; found: 536.9688.

[0187] 4) Preparation of C922-SO2CI (5b)

[0188]

[0189] CF3CF2CF2OCF(CF3)CF2OCF(CF3)CH2CH2SCN (5.4 g, 10 mmol), acetic acid (12 g, 0.2 mol) and nitrogen were added in an autoclave and heated to 45-50 °C. Chlorine (21 g, 30 mmol) was continuously bubbled into the mixture for 10 hours. At the same time, water was continuously added dropwise into the mixture for 8 hours. After that, the reaction was stirred at 45-50 °C for 1 hour. Chlorine (7 g, 10 mmol) was added for the second time at 45-50 °C for 2.5 hours and stirring was continued for 1 hour. The crude product was heated to 70 °C and washed with 60 g of ionized water. The organic layer was separated in a glass separation funnel, added to toluene (125 g, 1.36 mol), washed twice with 3.5 wt% sodium chloride solution (149 g) and after removal of excess solvent, passed through a column with 10 wt% of activated carbon (10 g) and 10 wt% of silica gel (10 g). 19 F-NMR and 1 H-NMR identification, the product obtained was 5b with a mass of 5.3 g and a yield of 90%.

[0190]

[0191] To a 100 mL three neck flask equipped with magnetic stirring, two septa and a ball jointed reflux condenser was added acetic acid (5 mL) as solvent and C922-SCN (4b) (2.68 g, 5 mmol). The reaction set up required a silicon tube attached to the outside of the ball jointed reflux condenser to vent the gases that might be generated into a 250 mL three neck flask (two ports capped with stoppers and one port vented to a 250 mL Erlenmeyer flask with a silicon tube) which acted as a buffer flask to prevent siphoning. The 250 mL Erlenmeyer flask was vented to a 10 wt% KOH solution which was used to absorb any acidic material that might be generated. Then using a 10 mL syringe, sulfuryl chloride (6.7 mL, 50 mmol) was added drop wise to the stirred mixture from one of the septa and using a 1 mL syringe, water (270 mg, 15 mmol) was added drop wise to the three neck flask from the other septa. At this point, the light yellow colored liquid mixture in the three neck flask turned a light red color and refluxed due to the heat of the exothermic reaction and the KOH solution in the Erlenmeyer flask started to bubble. The mixture was then heated to 50 °C and left to react for 18 hours. After the reaction was complete, the mixture was cooled to room temperature and then using a 10 mL syringe, about 10 mL of water was added to the three neck flask to quench any residual sulfuryl chloride in the mixture. The light red color of the liquid mixture turned to a light yellow color and the gas generated was absorbed by the KOH solution. After the quench was complete, the septa and the ball jointed reflux condenser were removed and the mixture was left to air blow in the hood for 5 minutes to remove any residual chlorine or hydrogen chloride. The mixture was then transferred to a 250 mL separatory funnel and 10 mL of dichloromethane was added and the mixture was shaken and allowed to stand for 3 minutes. The lower organic layer was then removed. The water layer was then extracted with 5 mL x 3 of dichloromethane. The organic layers were combined and since the product might react with the filter paper, the mixture was not dried and was directly used to remove the solvent using a rotary evaporator. The light yellow liquid was then dried using an oil pump with a cold trap and weighed to give 2.7 g of a light yellow liquid. 19 F-NMR and 1 H-NMR identification, the 2.7 g (4.6 mmol) of light yellow liquid obtained was 5b with a 93% yield.

[0192] C922-SO2Cl (5b) was prepared by the reaction of C922-SCN (4b) with sulfuryl chloride (5) as shown in Scheme 5. 1 H NMR, 19 F NMR, 13 C NMR, IR and HRMS were determined as follows:

[0193]

[0194] 3,4,4-Tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)butane-1-sulfonyl chloride (5b): colorless liquid in 93% yield.

[0195] 3,4,4,4-Tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)butane-1-sulfonyl chloride (5b): colorless liquid in 93% yield. 1 H NMR (400 MHz, CDC13) δ 3.81 (m, 2H), 2.91 (m, 2H). 19 F NMR (376 MHz, CDC13) δ -79.0 - -81.4 (m, 4F), -81.1 - -82.6 (m, 6F), -83.1 (m, 3F), -129.3 - -129.5 (m, IF), -129.7 (m, 2F), -145.2 (m, IF). 13 C NMR (100 MHz, CDC13) δ 57.1, 28.6 (d, J = 23 Hz), carbons corresponding to the CF3CF2CF2OCF(CF3)CF2OCF(CF3)- group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 3011, 2690, 1724, 1417, 1294, 1215, 931, 809, 658, 450. HRMS -ESI (m / z): calcd for C 10 H3O4ClF 17 S[M-H] - : 576.9175; found: 576.9175.

[0196] 5) Preparation of C922-Amine (6b)

[0197]

[0198] Dimethylaminopropylamine (306 mg, 3 mmol, 1.5 equiv.), triethylamine (404 mg, 4 mmol, 2 equiv.) and dry MTBE (8 mL) were charged into a 100 mL three necked round bottom flask equipped with a reflux condenser, magnetic stirrer and temperature probe. The C922-S02CI (5b) (1.2 g, 2 mmol, 1 equiv.) prepared using the method of Example 3 was then added dropwise into the stirred mixture using a 1 mL syringe. A significant amount of white smoke was observed to be generated and as stirring proceeded, the generated smoke was constantly absorbed and the liquid mixture in the flask turned into a white turbid solid-liquid mixture. The mixture was then heated to reflux and left to react for 24 hours. After the reaction was completed, the reaction flask was cooled to room temperature to obtain a white solid-liquid mixture which was transferred into a 250 mL separatory funnel and 15 mL of water and 20 mL of dichloromethane were introduced and the mixture was shaken repeatedly and left to stand. After 3 minutes, the lower organic phase was removed. The organic phase was extracted three times with 5 mL x 3 of dichloromethane and the organic phases were collected and 2 g of anhydrous sodium sulfate was added to dry the salt (in the form of a quicksand, not cake) and the salt was filtered using a funnel and the filtrate was collected. The solvent was then spun off on a rotary evaporator to obtain 1.1 g of an amber liquid with a yield of 85%.

[0199] Preparation of C922-Amine (6b) 1 H NMR, 19 F NMR, 13 C NMR and IR results are as follows:

[0200]

[0201] N-(3-(Dimethylamino)propyl)-3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)butane-1-sulfonamide

[0202] N-(3-(Dimethylamino)propyl)-3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)butane-1-sulfonamide (6b): amber liquid with a yield of 85%. 1 H NMR (400 MHz, CD3OD) δ 3.21 (m, 2H), 3.08 (t, J = 7.2 Hz, 2H), 2.74 (m, 2H), 2.42 (m, 2H), 2.27 (m, 6H), 1.72 (m, 2H). 19F NMR (376 MHz, CD3OD) δ -79.9 - -80.8 (m, IF), -81.3 (m, 3F), -82.8 - -83.3 (m, 6F), -84.6 (m, 3F), -129.5 - -129.9 (m, IF), -131.0 (m, 2F), -146.2 (m, IF). 13 C NMR (100 MHz, CD3OD) δ 57.7, 45.3, 45.2, 42.1, 28.84, 28.85 (d, J = 23 Hz), carbons corresponding to the CF3CF2CF2OCF(CF3)CF2OCF(CF3)- group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 3285, 2953, 2867, 2825, 2785, 1720, 1646, 1466, 1333, 1239, 1063, 993, 810, 746, 707, 535, 504.

[0203] 6) Preparation of C922S-Betaine (7b)

[0204]

[0205] C922S-Amine (6b) (2.0 g, 3 mmol, 1 equiv.), ethanol (8 mL), deionized water (4 mL), sodium chloroacetate (348 mg, 3 mmol, 1 equiv.) and sodium bicarbonate (318 mg, 3 mmol, 1 equiv.) were added to a 50 mL three necked round bottom flask equipped with a reflux condenser, magnetic stirrer and temperature probe. The reaction mixture was heated to 80 °C for 24 hours. Upon completion of the reaction, the resulting solid-liquid mixture was spun dry in a rotary evaporator to yield 1.8 g of white solid with 85% yield.

[0206] Preparation of C922S-Betaine (7b) 1 H NMR, 19 F NMR, 13 C NMR, IR and HRMS results are as follows:

[0207]

[0208] 2-(Dimethyl(3-((3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)butyl)sulfonamidyl)propyl)ammonio)acetate inner salt

[0209] 2-(Dimethyl(3-((3,4,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(perfluoropropoxy)propoxy)butyl)sulfonamido)propyl)ammonio)acetate (7b): white solid, yield 85%. 1 H NMR (400 MHz, CD3OD) δ 3.83 (s, 2H), 3.68 (m, 2H), 3.30 - 3.15 (m, 10H), 2.74 (m, 2H), 2.01 (m, 2H). 19 F NMR (376 MHz, CD3OD) δ -79.7 - -80.9 (m, IF), -81.5 (m, 3F), -82.2 - -84.1 (m, 6F), -84.7 (m, 3F), -129.5 - -130.0 (m, IF), -131.2 (m, 2F), -146.4 (m, IF). 13 C NMR (100 MHz, CD3OD) δ 168.8, 65.1, 63.2, 51.9, 45.0, 41.0, 28.7 (d, J = 23 Hz), 25.0, carbons corresponding to the CF3CF2CF2OCF(CF3)CF2OCF(CF3)- group cannot be identified due to C-F coupling. IR (film) v / cm -1 : 3421, 2115, 1635, 1485, 1400, 1333, 1237, 1154, 1074, 994, 940, 896, 808, 747, 707, 535. HRMS-DART (m / z): calcd for C 17 H 20 O6N2F 17 S[M+H] + : 703.0765; found: 703.0764.

[0210] Comparative Example 1

[0211] This comparative example provides C62S-Betaine (7c) (2-(dimethyl(3-((3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)sulfonamido)propyl)ammonio)acetate) for comparison and a process for its preparation comprising the following operational steps:

[0212] 1) Synthesis of C62S-Amine (6c)

[0213]

[0214] In a 10 mL Schlenk tube, add anhydrous MTBE (2 mL) as solvent and stir bar, add N,N-dimethyl-1,3-propanediamine (408 mg, 4 mmol, 2 equiv.) and triethylamine (404 mg, 4 mmol, 2 equiv.), then weigh C62-SO2Cl (5c) (892 mg, 2 mmol, 1 equiv.) using a 1 mL syringe and inject quickly along the wall of the tube, immediately tighten the pentafluoroethane plug. Warm the mixture to reflux, react for 24 hours, taking care to keep the stir bar always stirring. At the end of the reaction, transfer all the liquid from the Schlenk tube into a 250 mL separatory funnel, add brine (20 mL) and dichloromethane (10 mL), close the plug, shake vigorously, let stand. After 3 minutes, remove the lower organic phase. Then extract three times with dichloromethane 5 mL x 3, collect the lower organic phase and dry using anhydrous sodium sulfate. Filter the solid-liquid mixture, take the clear filtrate to the rotary evaporator to evaporate the solvent, finally obtain a yellow solid, pass it through a silica gel column using dichloromethane as eluent, collect the fractions containing the product, evaporate the solvent, finally obtain a yellow solid, weigh 690 mg of product (2.7 mmol), yield 68%. 19 F-NMR and 1 H-NMR identification confirmed that the product was 6c, weighing 690 mg of product (yellow solid, 2.7 mmol), yield 68%.

[0215] Synthesis of C62S-Amine (6c) 1 H NMR and 19 F NMR detection results are as follows:

[0216]

[0217] N-(3-(dimethylamino)propyl)-3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane-1-sulfonamide

[0218] N-(3-(dimethylamino)propyl)-3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane-1-sulfonamide (6c): yellow solid, yield 68%. 1 H NMR (400 MHz, CD3OD) δ 3.31 (m, 2H), 3.08 (m, 2H), 2.56 - 2.70 (m, 2H), 2.37 (m, 2H), 2.22 (s, 6H), 1.70 (m, 2H). 19F NMR (376 MHz, CD3OD) δ -82.5 (m, 3F), -114.9 (m, 2F), -123.0 (m, 2F), -124.0 (m, 2F), -124.4 (m, 2F), -127.4 (m, 2F).

[0219] 2) Synthesis of C62S-Betaine (7c)

[0220]

[0221] In a 10 mL Schlenk tube, a stir bar, sodium chloroacetate (116 mg, 1 mmol, 1 equiv.) and sodium bicarbonate (86 mg, 1 mmol, 1 equiv.) were added, followed by ethanol (1.5 mL) and water (0.75 mL) as solvents, and finally C62S-Amine (6c) (512 mg, 6.5 mmol, 1 equiv.) was weighed, the temperature was raised to 80 °C and the reaction was left for 24 h. After the reaction was completed, the resulting solid-liquid mixture was transferred to a 50 mL flask, and the solvent was evaporated in a rotary evaporator to obtain 510 mg of product with a yield of 90%.

[0222] Synthesis of C62S-Betaine (7c) 1 H NMR and 19 F NMR detection results are as follows:

[0223]

[0224] 2-(Dimethyl(3-((3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)sulfonamido)propyl)ammonio)acetate (7c): white solid, yield 90%.

[0225] 2-(Dimethyl(3-((3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)sulfonamido)propyl)ammonio)acetate (7c): white solid, yield 90%. 1 H NMR (400 MHz, CD3OD) δ 3.81 (s, 2H), 3.67 (m, 2H), 3.37 (m, 2H), 3.25 (s, 6H), 3.19 (t, J = 8 Hz, 2H), 2.61 - 2.74 (m, 2H), 2.00 (m, 2H). 19 F NMR (376 MHz, CD3OD) δ -82.4 (m, 3F), -114.8 (m, 2F), -123.0 (m, 2F), -123.9 (m, 2F), -124.3 (m, 2F), -127.4 (m, 2F).

[0226] Comparative Example 2

[0227] This comparative example provides a commercially available product Capstone 1157 from Solvay. It appears as a clear amber liquid with a density of about 1.03 g / mL. Its composition includes 27% of a fluorinated alkyl betaine (consistent with the structure of Comparative Example 1) and a mixture of ethanol and water as solvent.

[0228] Performance Testing

[0229] The surfactants prepared from the above examples and comparative examples were tested for the following properties:

[0230] I. Surface Tension Measurement

[0231] The surface tension of the surfactants was measured using the Wilhelmy plate method on a Kruss K100C mechanical surface tensiometer in deionized water. The platinum plate was 19.9 mm in length and 0.2 mm in thickness. The solutions were prepared in deionized water and a series of different concentrations were measured from 0.001% to 1% (or higher solubility of the surfactant). The data were measured at room temperature and the surface tension was measured five times to obtain an average value.

[0232] The surface tension of C722S-Betaine prepared from Example 1, C922S-Betaine prepared from Example 2, C62S-Betaine prepared from Comparative Example 1, and Capstone 1157 from Solvay (which contains C62S-Betaine as the main fluorosurfactant) were measured and the results are shown in Table 1 and Table 2. Figure 1

[0233] Table 2. Surface Tensiometric Properties of Various Betaine Surfactants

[0234]

[0235] The surface tension values of various amphoteric betaine surfactants at multiple concentrations were selected and recorded in Table 3.

[0236] Table 3. Surface Tension of Various Amphoteric Betaine Surfactants (25°C)

[0237]

[0238] From Figure 1 ​From the results of Table 2 and Table 3, it can be seen that the surface tension of C722S-Betaine, C62S-Betaine and Capstone 1157 at the critical micelle concentration can all reach below 18 mN / m, and the critical micelle concentration can all be reduced to 0.2 g / L. The results show that in terms of surface activity, C722-Betaine, C62S-Betaine and Capstone 1157 have equivalent effects at the same dosage, and have excellent surface activity. C922S-Betaine is different from the above three types of fluorinated surfactants, and its critical micelle concentration is extremely low, below 10 mg / L. Moreover, C922S-Betaine can also reach a surface tension below 20 mN / m at a concentration of 10 parts per million, and its ability to reduce surface tension at extremely low concentrations is far superior to the above three types of fluorinated surfactants.

[0239] II. Spreading Experiment

[0240] The foam extinguishing agent concentrate used in the experiment is formulated as follows: fluorinated surfactant (0.2 wt%), hydrocarbon surfactant (cocamidopropyl betaine, 35 wt%, 0.2 wt%), cosolvent (dipropylene glycol methyl ether, 1 wt%), and water as solvent.

[0241] The configuration process is as follows: first, 5 mg of C722S-Betaine prepared in Example 2 and 5 mg of C62S-Betaine prepared in Comparative Example 4 are added to two 10 mL volumetric flasks, respectively, then 60 mg of CAB-35 and 100 mg of dipropylene glycol methyl ether are added, and finally, deionized water is added to make up to 10 mL.

[0242] Spreading experiment: In two 6 cm diameter culture dishes, 20 mL of n-hexane is added. Two clean 100 μL microsyringes are used to rinse the syringes in the prepared surfactant solution. Then, 100 μL of the solution is drawn into the microsyringe and added to the n-hexane-containing culture dish, and the process is repeated continuously on the same droplet as much as possible until the water film forms a droplet and sinks to the bottom of the culture dish. The volume of the foam concentrate added to the culture dish at this time is recorded.

[0243] The experimental results are as follows:

[0244] C722S-Betaine is added to 130 μL, the water film forms a droplet, and the water droplet sinks, indicating that the foam concentrate can spread on n-hexane.

[0245] C62S-Betaine is added to 110 μL, the water film forms a droplet, and the water droplet sinks, indicating that the foam concentrate can spread on n-hexane.

[0246] The branched fluorine ether ethylene surfactant C722S-Betaine prepared by the present application can achieve better spreading performance than the currently used C62S-Betaine.

[0247] UV photodegradation experiment under titanium dioxide

[0248] At present, the method of using titanium dioxide for simple ultraviolet light (non-vacuum ultraviolet) cannot achieve efficient degradation of PFOA and other perfluoroalkyl compounds. In order to comprehensively evaluate the environmental performance of the fluorine ether surfactant prepared by the present application, and preliminarily verify the assumption of the degradation path in the design initial stage, the present application carries out titanium dioxide photodegradation on the newly synthesized fluorine ether surfactant molecules.

[0249] In order to verify the degradability of the branched fluorine ether ethylene structure, we prepared and synthesized Isomer-C722S-Betaine (7d) which is an analogue of C722S-Betaine, and its structure is

[0250] CF3OCF(CF3)CF2OCF2CF2CH2CH2SO2NH(CH2)3N + (CH3)2CH2COO -

[0251] Structural formula of Isomer-C722S-Betaine

[0252] Isomer-C722S-Betaine (7d) (2-(dimethyl(3-((3,3,4,4-tetrafluoro-3-(1,1,2,3,3,3-hexafluoro-2-(trifluoromethoxy)propoxy)butyl)sulfonamido)propyl)ammonio)acetate) and a preparation method thereof, comprising the following operation steps:

[0253] The method starts from fluorine ether alkyl trifluorovinyl ether C72VE (1d) according to the literature [J. Fluorine Chem. 2014, 161, 41-50], and through a fluorination-iodination process, Isomer-C72-I (2d) is obtained. Through ethylene insertion (product Isomer-C722-I, 3d), potassium thiocyanate substitution, thiocyanate product Isomer-C722-SCN (4d) is obtained. Isomer-C722-SCN (4d) is converted into isomer-C722-SO2Cl (5d) under the reaction conditions of sulfuryl chloride, and after amidation (product Isomer-C722-SO2Cl, 6d), betaine, the final product Isomer-C722S-Betaine (7d) is obtained.

[0254]

[0255] Method for preparing compound Isomer-C722S-Betaine (7d) is shown in the schematic diagram

[0256] The nuclear magnetic resonance data of the related compounds are as follows:

[0257] C72VE (1d):

[0258] 19 F NMR (376 MHz, neat) δ -55.9 (m, 3F), -82.2 (m, 3F), -86.6 (m, 2F), -117.5 (dd, J = 88, 67 Hz, IF), -124.9 (dd, J = 86, 113 Hz, IF), -138.3 (dd, J = 68, 112 Hz, IF), -147.6 (m, IF).

[0259] Isomer-C72-I (2d):

[0260] 19 F NMR (376 MHz, CDCl3) δ -53.4 (m, 3F), -65.3 (m, 2F), -79.8 (m, 3F), -83.4 (m, 2F), -85.7 (m, 2F), -146.4 (t, J = 15 Hz, IF).

[0261] Isomer-C722-I (3d):

[0262] 1 H NMR (400 MHz, CD3OD) δ 3.22 (t, J = 8 Hz, 2H), 2.63 (tt, J = 17, 9 Hz, 2H).

[0263] 19 F NMR (376 MHz, CD3OD) δ -53.3 (m, 3F), -79.8 (m, 3F), -83.1 (m, 2F), -87.7 (m, 2F), -119.0 (t, J = 17 Hz, 2F), -146.4 (t, J = 15 Hz, IF).

[0264] Isomer-C722-SCN (4d):

[0265] 1 H NMR (400 MHz, CD3OD) δ 3.22 (t, J = 8 Hz, 2H), 2.58 (tt, J = 17, 9 Hz, 2H).

[0266] 19F NMR (376 MHz, CD3OD) δ -53.3 (m, 3F), -79.8 (m, 3F), -83.1 (m, 2F), -87.7 (m, 2F), -118.0 (t, J = 17 Hz, 2F), -146.4 (t, J = 15 Hz, IF).

[0267] Isomer-C722-SO2Cl (5d):

[0268] 1 H NMR (400 MHz, CDCl3) δ 3.91 - 3.87 (m, 2H), 2.84 - 2.71 (m, 2H).

[0269] 19 F NMR (376 MHz, CDCl3) δ -53.3 (m, 3F), -79.8 (m, 3F), -83.1 (m, 2F), -87.5 (m, 2F), -117.4 (t, J = 17 Hz, 2F), -146.4 (t, J = 15 Hz, IF).

[0270] Isomer-C722-SO2Cl (6d):

[0271] 1 H NMR (400 MHz, CDCl3) δ 3.30 - 3.27 (m, 2H), 3.09 (t, J = 7 Hz, 2H), 2.64 - 2.50 (m, 2H), 2.41 - 2.36 (t, J = 7 Hz, 2H), 2.24 (s, 6H), 1.72 (tt, J = 7 Hz, 2H).

[0272] 19 F NMR (376 MHz, CDCl3) δ -54.9 (m, 3F), -81.3 (m, 3F), -84.3 (m, 2F), -88.8 (m, 2F), -119.0 (t, J = 17 Hz, 2F), -147.5 (t, J = 15 Hz, IF).

[0273] Isomer-C722S-Betaine (7d):

[0274] 1 H NMR (400 MHz, CDCl3) δ 3.81 (s, 2H), 3.69 - 3.64 (m, 2H), 3.37 - 3.33 (m, 2H), 3.25 (s, 6H), 3.18 (t, J = 7 Hz, 2H), 2.66 - 2.52 (m, 2H), 2.00 (m, 2H).

[0275] 19F NMR (376 MHz, CDCl3) δ -54.9 (m, 3F), -81.3 (m, 3F), -84.3 (m, 2F), -88.7 (m, 2F), -118.9 (t, J = 17 Hz, 2F), -147.5 (t, J = 15 Hz, IF).

[0276] The UV photodegradation experiment of titanium dioxide under UV light includes the following operations:

[0277] Preparation: 1 mmol of the substrate was weighed in a 10 mL beaker, dissolved in pure water, and then transferred to a 50 mL volumetric flask for constant volume to obtain a 1 mM solution, which was ready for use. Several clean 10 mL ground-neck test tubes were taken, and 10 mg of TiO2(anatase, hydrophilic, 2-3 nm) was added to each test tube. 5 mL of the prepared substrate solution was taken and added to the test tube, which was sealed with a sealing film.

[0278] Irradiation: a 254 nm UV lamp with a quartz wall (Philips, 36 W, G36 / T8) was taken. The prepared irradiation group was placed beside the UV lamp, and the UV lamp was turned on to start irradiation. The other group was placed in the dark to avoid light.

[0279] Pre-treatment and storage: first, the substrate adsorbed on the wall was desorbed by ultrasonic treatment for 10 minutes. Then, all the solid-liquid systems in the ground-neck test tube were taken out with a 5 mL syringe, and about 5 mL of clear liquid was collected in a 10 mL centrifuge tube by passing through a 0.22 μm nylon filter. The centrifuge tube was sealed. Before starting the test, all samples should be stored in the dark.

[0280] Test: before testing, dilute 1000 times, then use HPLC-MS / MS to detect, and analyze the samples under light and irradiation by combining standard samples.

[0281] After testing and data processing, the corresponding data was obtained.

[0282] The present application first explores the ordinary glass bottle as a reaction container for the photodegradation of titanium dioxide under UV light. In this experiment, C722S-Betaine in Example 1 and isomer-C722S-Betaine in the comparative example were selected as experimental objects, and the experimental results are shown in Table 4.

[0283] Table 4 Distribution of degradation products of two types of betaine under the preset degradation conditions within 72 hours

[0284]

[0285] Under the preset experimental environment, through the degradation experiment and the degradation product detection, the experiment confirms that the C722S-Betaine can realize the degradation of the fluoroether chain segment within 72 hours, and the main degradation product is the shorter chain perfluoroether carboxylic acid CF3OCF(CF3)CO2H (PMPA). In contrast, the isomer-C722S-Betaine fails to realize substantial degradation of the fluoroether chain segment within 72 hours, and its degradation products are mainly CF3OCF(CF3)CF2OCF2CF2CO2H and CF3OCF(CF3)CF2OCF2CO2H, both of which are long-chain fluoroether carboxylic acids.

[0286] In contrast, the C722S-Betaine prepared in the patent can substantially degrade the fluoroether chain segment due to the branched fluoroether ethylene structure, especially the branched-OCF(CF3)CH2CH2- structure, and the degradation product is mainly the shorter chain fluoroether carboxylic acid PMPA; while the degradation product of the comparative substance isomer-C722S-Betaine is mainly long-chain fluoroether carboxylic acid, and sufficient short-chain fluoroether is not found, which means that the comparative analogue isomer-C722S-Betaine can only realize the degradation of the ethylene part due to the structural difference (i.e. -OCF2CF2CH2CH2-), and it is difficult to further degrade into shorter chain PMPA. Therefore, the degradation experiment comparison in the patent reflects the degradation superiority of C722S-Betaine different from general betaine surfactants with fluoroether or perfluoro chain segments, that is, the structure of the patent can realize more thorough degradation of the fluoroether chain segment under suitable preset conditions, and generate shorter chain fluoroether carboxylic acid.

[0287]

[0288] Degradability experiment result graph

[0289] From the degradation experiment, the C722S-Betaine surfactant molecule can realize substantial degradation of the fluoroether chain segment under more moderate conditions, forming a short-chain fluorocarbon molecule without persistent pollution, which reflects the unique degradability and to some extent alleviates the contradiction between performance and environment.

[0290] The above merely describes preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A degradable surfactant, characterized by, Comprising the following structure: Structure 1 wherein R1is selected from CF3(CF2) m OCF(CF3)-, m = 0, 1 or 2, n = 2 or 3, R2is selected from H or CH3-, R3, R4are selected from CH3-, R5is selected from -CH2- or -CH2CH2-, A is selected from -CO2.

2. The degradable surfactant of claim 1, wherein, The degradable surfactant is selected from one or more of the following compounds: 。 3. The method for preparing the biodegradable surfactant according to any one of claims 1 to 2, characterized in that, Comprising the following operational steps: Structure 2 Obtaining a sulfonyl chloride compound shown in structure 2, using the sulfonyl chloride compound shown in structure 2 as a reaction precursor, preparing a tertiary amine through amidation, and then converting the tertiary amine into a betaine to prepare the compound shown in structure 1.

4. The method for preparing the biodegradable surfactant according to claim 3, characterized in that, The sulfonyl chloride compound shown in structure 2 is prepared by the following method: Structure 3 Obtaining a thiocyanate compound shown in structure 3, and chlorinating the thiocyanate compound shown in structure 3 by using chlorine gas or thionyl chloride to obtain the sulfonyl chloride compound shown in structure 2.

5. The method for preparing the biodegradable surfactant according to claim 4, characterized in that, The thiocyanate compound shown in structure 3 is prepared by the following method: Structure 4 Obtaining an iodo compound shown in structure 4, and reacting the iodo compound shown in structure 4 with potassium thiocyanate to obtain the thiocyanate compound shown in structure 3.

6. The method for preparing the biodegradable surfactant according to claim 5, characterized in that, The iodo compound shown in structure 4 is prepared by the following method: Structure 5 Obtaining an iodo compound shown in structure 5, and adding the iodo compound shown in structure 5 to ethylene to obtain the iodo compound shown in structure 4.

7. The method for preparing the biodegradable surfactant according to claim 6, characterized in that, The iodo compound shown in structure 5 is prepared by the following method: Structure 6 Obtaining an acyl fluoride shown in structure 6, and reacting the acyl fluoride shown in structure 6 with iodine in the presence of sodium carbonate, and then distilling and purifying to obtain the iodo compound shown in structure 5.

8. The method for preparing the biodegradable surfactant according to claim 3, characterized in that, The operation of "preparing a tertiary amine through amidation, and then converting the tertiary amine into a betaine" comprises: Structure 7 Structure 8 Structure 9 Structure 10 Reacting the sulfonyl chloride compound shown in structure 2 with a compound shown in structure 7 in the presence of triethylamine to obtain a fluoroether ethyl sulfonamide shown in structure 8; Reacting the fluoroether ethyl sulfonamide shown in structure 8 with a compound shown in structure 9 to obtain a betaine shown in structure 10.

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