A sulfonate type fluorosurfactant having excellent degradability and emulsifying performance and a method for preparing the same

Abstract

The application provides a sulfonate type fluorine surfactant with excellent degradability and emulsifying performance and a preparation method thereof, and relates to the field of fine chemical synthesis. The sulfonate type fluorine surfactant is prepared by firstly introducing methylene into a hydrophobic tail through free radical polymerization reaction of halogenated fluorine alkane and fluorine alkene under an initiator, which can be biodegraded or enzymatically degraded, reduces harm to human body and pollution to ecological environment, then substituting a halogen atom with a hydroxyl group under the condition of heating sodium hydroxide aqueous solution, and then introducing an alkoxy group through ring-opening polymerization reaction of the alkoxy group with an alkylene oxide to increase the hydrophilicity of the surfactant, and finally substituting a hydrogen atom in an alcohol hydroxyl group with sodium and then reacting with sodium halogenated sulfonate to introduce a sodium sulfonate group as a head group, so that the surfactant has lower surface tension and critical micelle concentration.

Description

Technical Field

[0001] The present invention relates to the field of fine chemical synthesis, and in particular to a sulfonate-type fluorosurfactant that is degradable and has excellent emulsification performance, and a preparation method thereof. Background Art

[0002] Fluorosurfactants are surfactants with fluorocarbon chains as non-polar groups, meaning that fluorine atoms partially or completely replace hydrogen atoms on hydrocarbon chains. The hydrophobic effect of fluorocarbon chains is much stronger than that of hydrocarbon chains, allowing fluorosurfactants to significantly reduce the surface tension of aqueous solutions at extremely low concentrations. The bond energy of the fluorocarbon bond (FC) is very high, one of the highest known covalent bonds. Therefore, fluorosurfactants have good thermal and chemical stability and can stably exist and function under harsh conditions such as high temperature, strong acid, strong base, and strong oxidizing media. Fluorine atoms are very difficult to polarize, making the polarity of fluorocarbon chains smaller than that of hydrocarbon chains. This helps fluorosurfactants to align and align into molecular films at the liquid / gas interface, thereby further reducing surface tension.

[0003] However, certain components in fluorosurfactants, such as perfluorooctane sulfonic acid (PFOS) and its derivatives, are persistent and difficult to degrade in the environment and organisms. These substances can accumulate in organisms and be transferred through the food chain, causing long-term impacts on ecosystems. Due to the unique properties of fluorosurfactants, they can migrate through the atmosphere, water bodies, and soil, and even cross national borders, posing a threat to the global environment. Under high temperatures or in strong acidic or alkaline environments, some fluorosurfactants may decompose, producing toxic gases that pose a direct threat to the human body. People exposed to fluorosurfactants for a long time may experience health problems such as skin irritation, respiratory damage, and immune system abnormalities. Fluorosurfactants may also affect the growth and reproduction of organisms, posing a potential threat to aquatic life and terrestrial ecosystems.

[0004] Fluorosurfactants with long carbon-fluorine chains are difficult to degrade, posing adverse environmental and human health risks. Therefore, efforts are underway to identify suitable alternatives. However, most approaches to synthesizing these alternatives have encountered challenges such as poor water solubility, insufficient surface emulsification, and difficulty degrading. Studies have shown that the biodegradability of fluorosurfactants can be enhanced by adding "weak sites" such as methine (CH) or methylene (CH2) groups to the hydrophobic tail. These "weak sites" can be degraded by organisms or enzymes, converting the long, recalcitrant carbon-fluorine chains into shorter, less bioaccumulative carbon-fluorine chains. Furthermore, the introduction of ethoxy and sulfonic acid groups can reduce the surface tension of the surfactant, enabling micelle formation at lower concentrations and thus improving its emulsification properties. Therefore, the development of biodegradable sulfonate-based fluorosurfactants with excellent emulsification properties and methods for their preparation are of great significance. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the present invention provides a sulfonate-type fluorosurfactant with excellent emulsification performance and a preparation method thereof. First, a free radical polymerization reaction is carried out with a halogenated fluoroalkane and a fluoroolefin in the presence of an initiator to introduce methylene groups into the hydrophobic tail. These methylene groups can be biodegraded or enzymatically degraded. Subsequently, the halogen atoms are replaced with hydroxyl groups under heating conditions with a sodium hydroxide aqueous solution. Then, a ring-opening polymerization reaction is carried out with an alkylene oxide to introduce alkoxy groups to increase the hydrophilicity of the surfactant. Finally, the hydrogen atoms in the alcoholic hydroxyl groups are replaced with sodium, and then the reaction is carried out with a halogenated sodium sulfonate to introduce a sodium sulfonate group as a head group, which has lower surface tension and critical micelle concentration.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A biodegradable sulfonate-type fluorosurfactant with excellent emulsification properties, the surfactant structure is as follows:

[0008] Where R1=C n F 2n+1 , n=1-6; R2=CF2 or CHCF3, x=1-5; R3=H or CH3, y=1-30, all are integers.

[0009] The preparation method of sulfonate type fluorosurfactant comprises the following steps:

[0010] (1) Preparation of a methylene-containing halogenated fluoroalkane: a halogenated fluoroalkane and a fluoroolefin are subjected to a free radical polymerization reaction in the presence of an initiator to introduce a methylene group into the hydrophobic tail, thereby preparing a methylene-containing halogenated fluoroalkane, wherein the components are calculated by weight as follows: 1-24 parts of initiator, 0.5-50 parts of fluoroolefin, and 0.25-100 parts of halogenated fluoroalkane;

[0011] (2) Preparation of fluoroalkanols and fluoroalkanol ethers: The above-mentioned methylene-containing halogenated fluoroalkanes are heated in a sodium hydroxide aqueous solution to replace the halogen atom with a hydroxyl group to obtain fluoroalkanols, and then the fluoroalkanols are subjected to a ring-opening polymerization reaction with an alkylene oxide in a mass percentage of 1-4:0.25-8 to introduce an alkoxy group to obtain fluoroalkanol ethers;

[0012] (3) Preparation of sulfonate type fluorosurfactant: The hydrogen atom in the alcoholic hydroxyl group of the above fluoroalkyl ether is replaced with sodium, and then reacted with sodium halide sulfonate to introduce sodium sulfonate group as the head group to obtain sulfonate type fluorosurfactant.

[0013] Preferably, the fluoroolefin in step (1) is at least one of vinyl fluoride, vinylidene fluoride, and trifluoropropylene.

[0014] Preferably, the halogenated fluoroalkane in step (1) is at least one of CF3I, CF3Br, CF3Cl, C2F5I, C2F5Br, C2F5Cl, C3F7I, C3F7Br, C3F7Cl, C4F9I, C6F13I.

[0015] Preferably, the initiator in step (1) is at least one of t-butyl peroxypivalate, cyclohexyl t-butyl peroxydicarbonate, azobisisobutyronitrile.

[0016] Preferably, the specific operation of step (1) is as follows: after high pressure sterilization and nitrogen purging, the high pressure sterilizer is placed in a vacuum state, the initiator, fluoroalkene and halogenated fluoroalkane are added, and the reaction is carried out at 30-120°C for 2-9 hours; after the reaction, the high pressure sterilizer is cooled to room temperature, and then placed in an ice bath for 10-40 min; after degassing of the unreacted monomer, the container is opened, the polymer is dissolved in acetone, and the polymer is precipitated from cold pentane; the polymer is filtered, washed and vacuum dried to obtain a methylene-containing halogenated fluoroalkane.

[0017] Preferably, the specific operation of step (1) is as follows: the alkylene oxide in step (2) is at least one of ethylene oxide, propylene oxide, cyclohexene oxide.

[0018] Preferably, the specific operation of step (2) is as follows: the methylene-containing halogenated fluoroalkane in step (1) is reacted in a sodium hydroxide aqueous solution at 20-50°C for 0.5-2 hours to obtain a fluoroalkanol; then the fluoroalkanol is transferred to a high pressure reaction kettle, the alkylene oxide is added, and the reaction is carried out at 0.05-0.55 MPa and 70-180°C for 1-4 hours to obtain a fluoroalkanol ether.

[0019] Preferably, the sodium halogenated sulfonate in step (3) is at least one of sodium 2-chloroethyl sulfonate and sodium 2-bromoethyl sulfonate.

[0020] Preferably, the specific operation of step (3) is as follows: the Na and THF distillate are sequentially placed in a flask, mixed and stirred for 10-40 minutes to obtain a mixed solution, then the fluoroalkanol ether obtained in step (2) and the mixed solution are added dropwise into an ice bath flask, after the addition process is completed, the reaction is continued in the ice bath for 2-5 hours, then stirring is carried out in nitrogen at 15-30°C for 1-4 hours, then the sodium halogenated sulfonate-containing distillate THF is added dropwise, the reaction solution is heated at reflux at 40-80°C for 36-72h, and the end point is determined by thin layer chromatography; after natural cooling at room temperature, THF is removed from the product mixture under vacuum using a rotary evaporator, and then the product is separated by column chromatography to obtain a sulfonate-type fluorine surfactant; and the raw materials are Na 0.05-1 parts, THF distillate 10-300 parts, fluoroalkanol ether 0.5-75 parts, and sodium halogenated sulfonate 0.25-30 parts by weight.

[0021] The present invention provides a biodegradable sulfonate-type fluorosurfactant with excellent emulsification properties, which has the following advantages over the prior art:

[0022] (1) The sulfonate-type fluorosurfactant prepared by the present invention introduces methylene units between the hydrophobic tail carbon fluorine chains, which can be biodegraded or enzymatically degraded, thereby reducing harm to the human body and ecological environment pollution. In the aggregation behavior of the carbon fluorine hydrophobic tail, a branched hydrophobic tail can be used instead of a straight hydrophobic tail to prevent the impact on the emulsification performance of the surfactant;

[0023] (2) The sulfonate-type fluorosurfactant prepared by the present invention introduces an ethoxy group with controllable molecular weight, which increases the hydrophilicity of the surfactant. The molecular weight can be adjusted as needed to cope with different practical application scenarios;

[0024] (3) The sulfonate-type fluorosurfactant prepared by the present invention introduces sodium sulfonate containing ethoxy groups. For fluorinated surfactants in aqueous solution, sulfonates have lower surface tension and critical micelle concentration than carboxylates. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The synthetic route of the sulfonate type fluorosurfactant prepared by the present invention, wherein R f is CF2 or CH—CF3, X is a halogen atom I or Cl or Br, R is H or CH3, n=1-6, x=1-5, y=1-30;

[0026] Figure 2 is the H NMR spectrum of the product of Reaction Formula I in Example 1;

[0027] Figure 3 is the H NMR spectrum of the intermediate and product of Reaction Formula II in Example 1;

[0028] Figure 4 is the H NMR spectrum of the intermediate and product of Reaction Formula III in Example 1;

[0029] Figure 5 is the H NMR spectrum of the product of Reaction Formula IV in Example 2;

[0030] Figure 6 is the H NMR spectrum of the intermediate and product of Reaction Formula V in Example 2;

[0031] Figure 7 is the H NMR spectrum of the intermediate and product of Reaction Formula VI in Example 2;

[0032] Figure 8 is the H NMR spectrum of the product of reaction formula VII in Example 3;

[0033] Figure 9: is the H NMR spectrum of the intermediate and product of Reaction Formula VIII in Example 3;

[0034] Figure 10 1H NMR spectra of the intermediate and product of Reaction Formula IX in Example 3;

[0035] Figure 11 1 is the H NMR spectrum of the intermediate and product of Reaction Formula X in Comparative Example. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] Example 1:

[0038] Preparation of sulfonate type fluorosurfactant:

[0039] 1. Preparation of iodofluoroalkanes containing methylene:

[0040] After 20 minutes of autoclave sterilization and a 30 bar nitrogen purge, the autoclave was placed under vacuum. 6.70 g of the initiator tert-butyl peroxypivalate, 6.40 g of vinylidene fluoride, and 12.30 g of pentafluoroiodoethane were added and reacted at 75°C for 6 hours. After the reaction, the autoclave was cooled to room temperature and then placed in an ice bath for 30 minutes. The reaction was then degassed, the container opened, and the polymer dissolved in acetone and precipitated from cold pentane. The polymer was filtered, washed, and vacuum-dried to yield a methylene-containing iodofluoroalkane, according to the following reaction equation:

[0041]

[0042] Depend on Figure 2 The H-NMR spectrum showed that there was an absorption peak at 3.1 ppm and 3.2 ppm, respectively, proving the synthesis of 1,1,1,2,2,4,4,6,6-nonafluoro-6-iodohexane in formula Ⅰ.

[0043] 2. Preparation of fluoroalkanols and fluoroalkanol ethers:

[0044] 18.70 g of the methylene-containing iodofluoroalkane from step 1 was reacted in a sodium hydroxide aqueous solution at 40° C. for 1 hour to obtain a fluoroalkanol; the mixture was then transferred to an autoclave, 4.41 g of ethylene oxide was added, and the reaction was carried out at 0.05-0.55 MPa and 130° C. for 2 hours to obtain a fluoroalkanol ether. The reaction equation is as follows:

[0045]

[0046] Depend on Figure 3 As shown in the hydrogen spectrum of a, the absorption peak at 3.23ppm is the hydroxyl hydrogen absorption peak of the intermediate product, proving the synthesis of 1,1,1,2,2,4,4,6,6-nonafluoro-6-iodohexane in formula II. Figure 3 As shown in b, the absorption peak of hydrogen on the ethoxy group is between 3.6 and 3.8 ppm, which proves that the final product ((1,1,3,3,5,5,6,6,6-nonafluorohexyl)oxy)diethoxy-1-ol is obtained.

[0047] 3. Preparation of sulfonate type fluorosurfactant:

[0048] 1.50 g of Na and 50 mL of (tetrahydrofuran) THF distillate were placed in a 500 mL flask and stirred for 30 minutes. Then, a solution containing 17.60 g of the fluoroalkyl alcohol ether obtained in step 2 and 100 ml of distilled THF was added dropwise to the ice bath flask. After the addition process was completed, the reaction was continued in the ice bath for 4 hours, and then stirred in nitrogen at 25°C for 2 hours. Subsequently, 100 mL of distilled THF containing 7.69 g of sodium 2-chloroethylsulfonate was added dropwise, and the reaction solution was refluxed at 65°C for 60 hours. The endpoint was determined by thin layer chromatography. After cooling to room temperature, THF was removed from the product mixture using a rotary evaporator under vacuum, and the product was separated by column chromatography to obtain a sulfonate-type fluorosurfactant. The reaction equation is as follows:

[0049]

[0050] Depend on Figure 4 As shown in the hydrogen spectrum of a, the absorption peak at 3.6-3.8ppm is split into a triplet peak due to the introduction of sodium in reaction formula III, proving that the intermediate product 2-(2-((1,1,3,3,5,5,6,6,6-nonafluorohexyl)oxy)ethoxy sodium is obtained. Figure 4 As shown in Figure b, due to the introduction of the sulfonic acid group, there is an absorption peak at 3.83 ppm, which proves that the final product is sodium (1,1,3,3,5,5,6,6,6-nonafluorohexyl)oxy)diethoxysulfonate.

[0051] Example 2:

[0052] Preparation of sulfonate type fluorosurfactant:

[0053] 1. Preparation of bromofluoroalkanes containing methylene:

[0054] After 20 minutes of autoclave sterilization and 30 bar of nitrogen pressure purge, the autoclave was placed under vacuum, and 15.33 g of initiator cyclohexyl tert-butyl peroxydicarbonate, 14.41 g of trifluoropropylene, and 7.45 g of trifluorobromomethane were added and reacted at 60°C for 8 hours. After the reaction, the autoclave was cooled to room temperature and then placed in an ice bath for 30 minutes. After the unreacted trifluoropropylene monomer was degassed, the container was opened and the polymer was dissolved in acetone and precipitated from cold pentane. The polymer was filtered, washed, and vacuum dried to obtain a methylene-containing bromofluoroalkane. The reaction equation is as follows:

[0055]

[0056] Depend on Figure 5 The H-NMR spectrum showed absorption peaks at 2.1-2.6 ppm and 4.8 ppm, respectively, proving the successful preparation of the product 2-bromo-1,1,1,6,6,6-hexafluoro-4-(trifluoromethyl)hexane in formula IV.

[0057] 2. Preparation of fluoroalkanols and fluoroalkanol ethers:

[0058] 19.41 g of the methylene-containing bromofluoroalkane from step 1 was reacted in a sodium hydroxide aqueous solution at 40° C. for 1 hour to obtain a fluoroalkanol; the mixture was then transferred to an autoclave, 5.81 g of propylene oxide was added, and the reaction was carried out at 0.05-0.55 MPa and 140° C. for 3 hours to obtain a fluoroalkanol ether. The reaction equation is as follows:

[0059]

[0060] Depend on Figure 6 As shown in the hydrogen spectrum of a, the absorption peak at 4.12ppm is the hydroxyl hydrogen absorption peak of the intermediate product, proving the synthesis of 1,1,1,6,6,6-hexafluoro-4-(trifluoromethyl)hexan-2-ol in formula V. Figure 6 As shown in b, the absorption peak of hydrogen on the ethoxy group is between 1.2-4.2 ppm, which proves that the final product is (1,1,1,6,6,6-hexafluoro-4-(trifluoromethyl)hexan-2-yl)oxy)propan-2-yl)oxy)propan-2-ol.

[0061] 3. Preparation of sulfonate type fluorosurfactant:

[0062] 1.50 g of Na and 50 mL of (tetrahydrofuran) THF distillate were placed in a 500 mL flask and mixed and stirred for 30 minutes. Then, a solution containing 24.50 g of the fluoroalkyl ether obtained in step 2 and 70 ml of distilled THF was added drop by drop to the ice bath flask. After the addition process was completed, the reaction was continued in the ice bath for 3 hours, and then stirred for 1.5 hours in nitrogen at 25°C. Subsequently, 70 mL of distilled THF containing 8.88 g of sodium 2-bromoethylsulfonate was added dropwise, and the reaction solution was refluxed at 60°C for 48 hours. The end point was determined by thin layer chromatography. After natural cooling to room temperature, THF was removed from the product mixture using a rotary evaporator under vacuum, and the product was separated by column chromatography to obtain a sulfonate-type fluorosurfactant. The reaction equation is as follows:

[0063]

[0064] Depend on Figure 7 As shown in the hydrogen spectrum of a, due to the introduction of sodium in reaction formula VI, the absorption peak at 2.1-2.3ppm changes from a triplet peak to a strong absorption peak, proving that the intermediate product (1,1,1,6,6,6-hexafluoro-4-(trifluoromethyl)hexan-2-yl)oxy)propoxy sodium is obtained. Figure 7 As shown in Figure b, due to the introduction of sulfonic acid group, there is a strong absorption peak at 3.23 ppm, which proves that the final product is sodium (1,1,1,6,6,6-hexafluoro-4-(trifluoromethyl)hexan-2-yl)propoxysulfonate.

[0065] Example 3:

[0066] Preparation of sulfonate type fluorosurfactant:

[0067] 1. Preparation of iodofluoroalkanes containing methylene:

[0068] After 20 minutes of high-pressure sterilization and 30 bar of nitrogen pressure purge, the autoclave was placed under vacuum, and 15.33g of initiator cyclohexyl tert-butyl peroxydicarbonate, 14.41g of trifluoropropylene and 7.45g of trifluoroiodomethane were added and reacted at 60°C for 8 hours. After the reaction, the autoclave was cooled to room temperature and then placed in an ice bath for 30 minutes. After the unreacted trifluoropropylene monomer was degassed, the container was opened and the polymer was dissolved in acetone and precipitated from cold pentane. The polymer was filtered, washed and vacuum dried to obtain a bromofluoroalkane containing a methylene group. The reaction equation is as follows:

[0069]

[0070] Depend on Figure 8The H-NMR spectrum showed absorption peaks at 2.1-2.5 ppm and 4.8 ppm, respectively, proving the successful preparation of the product 1,1,1,6,6,6-hexafluoro-2-iodo-4-(trifluoromethyl)hexane in formula VII.

[0071] 2. Preparation of fluoroalkanols and fluoroalkanol ethers:

[0072] 19.41 g of the methylene-containing iodofluoroalkane from step 1 was reacted in a sodium hydroxide aqueous solution at 40° C. for 1 hour to obtain a fluoroalkanol; the mixture was then transferred to an autoclave, 11.01 g of ethylene oxide was added, and the reaction was carried out at 0.05-0.55 MPa and 140° C. for 5 hours to obtain a fluoroalkanol ether. The reaction equation is as follows:

[0073]

[0074] Depend on Figure 9 a The hydrogen spectrum shows that the absorption peak at 4.14ppm is the hydroxyl hydrogen absorption peak of the intermediate product, proving the synthesis of 1,1,1,6,6,6-hexafluoro-4-(trifluoromethyl)hexan-2-ol in formula VIII. Figure 9 As shown in b, the absorption peak of hydrogen on the ethoxy group is between 1.2-4.2 ppm, which proves that the final product 20,20,20-trifluoro-16,18-bis(trifluoromethyl)-3,6,9,12,15-pentahydroicosane-1-ol is obtained.

[0075] 3. Preparation of sulfonate type fluorosurfactant:

[0076] 1.50 g of Na and 50 mL of (tetrahydrofuran) THF distillate were placed in a 500 mL flask and stirred for 30 minutes. Then, a solution containing 30.24 g of the fluoroalkyl ether obtained in step 2 and 100 ml of distilled THF was added dropwise to the ice bath flask. After the addition process was completed, the reaction was continued in an ice bath for 4 hours, and then stirred in nitrogen at 25°C for 1.5 hours. Subsequently, 100 mL of distilled THF containing 7.69 g of sodium 2-chloroethylsulfonate was added dropwise, and the reaction solution was refluxed at 65°C for 72 hours. The endpoint was determined by thin layer chromatography. After cooling naturally to room temperature, THF was removed from the product mixture using a rotary evaporator under vacuum, and the product was separated by column chromatography to obtain a sulfonate-type fluorosurfactant. The reaction equation is as follows:

[0077]

[0078] Depend on Figure 10 As shown in the hydrogen spectrum of a, the hydroxyl absorption peak at 3.38ppm disappears due to the introduction of sodium in reaction formula IX, proving that the intermediate product (1,1,1,6,6,6-hexafluoro-4-(trifluoromethyl)hexan-2-yl)oxy)propoxy sodium is obtained. Figure 10As shown in Figure b, due to the introduction of the sulfonic acid group, there is a strong absorption peak at 3.12 ppm, proving that the final product is sodium 23,23,23-trifluoro-19,21-bis(trifluoromethyl)-3,6,9,12,15,18-hexahydroheptadecanesulfonate.

[0079] Comparative Example 1:

[0080] Preparation of sulfonate type fluorosurfactant:

[0081] 1.50 g of Na and 50 mL of (tetrahydrofuran) THF distillate were placed in a 500 mL flask and stirred for 30 minutes. Then, a solution of 23.21 g of 2-perfluorooctylethanol and 100 ml of distilled THF was added dropwise to the ice bath flask. After the addition process was completed, the reaction was continued in the ice bath for 4 hours, and then stirred for 2 hours in nitrogen at 25°C. Subsequently, 100 mL of distilled THF containing 7.69 g of sodium 2-chloroethylsulfonate was added dropwise, and the reaction solution was refluxed at 65°C for 60 hours. The endpoint was determined by thin layer chromatography. After cooling to room temperature, THF was removed from the product mixture using a rotary evaporator under vacuum, and the product was separated by column chromatography to obtain a sulfonate-type fluorosurfactant. The reaction equation is as follows:

[0082]

[0083] Depend on Figure 11 As shown in the hydrogen spectrum of a, the hydroxyl absorption peak at 4.12ppm disappears due to the introduction of sodium in reaction formula X, proving that the intermediate product 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-dodecafluorodecane sodium is obtained. Figure 11 As shown in Figure b, due to the introduction of sulfonic acid groups, the absorption peaks at 3.13 ppm and 3.52 ppm prove that the final product is sodium 2-((3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-dodecafluorodecyl)oxy)ethane-1-sulfonate.

[0084] Detection:

[0085] 1. The molecular weights of the sulfonate surfactants prepared in Examples 1-3 and Comparative Example 1 were tested according to the standard GB / T11988-2008. The test results are shown in Table 1.

[0086] 2. The surface tension of the sulfonate surfactants prepared in Examples 1-3 and Comparative Example 1 was tested according to the standard GB / T22237-2008. The test results are shown in Table 1.

[0087] 3. The biodegradability of the sulfonate surfactants prepared in Examples 1-3 and Comparative Example 1 was tested according to standard GB / T15818-2018. The test results are shown in Table 1.

[0088]

[0089] As can be seen from the data in the table, the preparation method of the present invention can be used to obtain sulfonate surfactants of different molecular weights by adjusting the values ​​of n, x, and y. As can be seen from Comparative Example 1, the equilibrium surface tensions of the sulfonate surfactants in Examples 1-3 are all lower than those in Comparative Example 1, the critical micelle concentrations are all lower than those in Comparative Example 1, and the content of long-chain fluorocarbons in the biodegradation products is much lower than that in Comparative Example 1, indicating that the overall performance of the sulfonate surfactants obtained by the preparation method of the present invention is improved.

[0090] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A sulfonate-type fluorosurfactant, characterized in that: The surfactant structure is as follows: Where R1=C n F 2n+1 , n=1-6; R2=CF2 or CHCF3, x=1-5; R3=H or CH3, y=1-30, all are integers.

2. A method for preparing a surfactant according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Preparation of a methylene-containing halogenated fluoroalkane: a halogenated fluoroalkane and a fluoroolefin are subjected to a free radical polymerization reaction in the presence of an initiator to introduce a methylene group into the hydrophobic tail, thereby preparing a methylene-containing halogenated fluoroalkane, wherein the components are calculated by weight as follows: 1-24 parts of initiator, 0.5-50 parts of fluoroolefin, and 0.25-100 parts of halogenated fluoroalkane; (2) Preparation of fluoroalkanols and fluoroalkanol ethers: The above-mentioned methylene-containing halogenated fluoroalkanes are heated in a sodium hydroxide aqueous solution to replace the halogen atom with a hydroxyl group to obtain fluoroalkanols, and then the fluoroalkanols are subjected to a ring-opening polymerization reaction with an alkylene oxide in a mass percentage of 1-4:0.25-8 to introduce an alkoxy group to obtain fluoroalkanol ethers; (3) Preparation of sulfonate-type fluorosurfactants: The hydrogen atoms in the alcoholic hydroxyl groups of the above-mentioned fluoroalkyl ethers are substituted with sodium, and then reacted with sodium halide sulfonate to introduce sodium sulfonate groups as head groups to obtain sulfonate-type fluorosurfactants; The specific synthetic route of the preparation is as follows: Where R1=C n F 2n+1 , n=1-6; R2=CF2 or CHCF3, x=1-5; R3=H or CH3, y=1-30, all are integers.

3. The preparation method according to claim 2, wherein: In the step (1), the fluoroolefin is at least one of vinylidene fluoride and trifluoropropylene.

4. The preparation method according to claim 2, wherein: The halogenated fluoroalkane in step (1) is CF3I, CF3Br, CF3Cl, C2F5I, C2F5Br, C2F5Cl, C3F7I, C3F7Br, C3F7Cl, C4F9I, C6F 13 At least one of I.

5. The preparation method according to claim 2, wherein: The initiator in step (1) is at least one of tert-butyl peroxypivalate, tert-butyl cyclohexyl peroxydicarbonate, and azobisisobutyronitrile.

6. The preparation method according to claim 2, wherein: The specific operation of step (1) is as follows: after high-pressure sterilization and nitrogen purging, the autoclave is placed in a vacuum state, an initiator, a fluoroolefin and a halogenated fluoroalkane are added, and the reaction is carried out at 30-120° C. for 2-9 hours; after the reaction, the autoclave is cooled to room temperature and then placed in an ice bath for 10-40 minutes; after the unreacted monomer is degassed, the container is opened, the polymer is dissolved in acetone, and precipitated from cold pentane; the polymer is filtered, washed and vacuum dried to obtain a halogenated fluoroalkane containing a methylene group.

7. The preparation method according to claim 2, characterized in that: In the step (2), the alkylene oxide is at least one of ethylene oxide and propylene oxide.

8. The preparation method according to claim 2, wherein: The specific operation of step (2) is as follows: reacting the methylene-containing halogenated fluoroalkane in step (1) in a sodium hydroxide aqueous solution under heating conditions of 20-50° C. for 0.5-2 hours to obtain a fluoroalkanol; then transferring the fluoroalkanol to a high-pressure reactor, adding alkylene oxide, and reacting at 0.05-0.55 MPa and 70-180° C. for 1-4 hours to obtain a fluoroalkanol ether.

9. The preparation method according to claim 2, wherein: The sodium halide sulfonate in step (3) is at least one of 2-chloroethyl sodium sulfonate and 2-bromoethyl sodium sulfonate.

10. The preparation method according to claim 2, characterized in that: The specific operation of step (3) is as follows: Na and THF distillate are sequentially placed in a flask and mixed and stirred for 10-40 minutes to obtain a mixed solution, and then the fluoroalkyl alcohol ether and the mixed solution obtained in step (2) are added dropwise to an ice bath flask, and after the addition process is completed, the reaction is continued in an ice bath for 2-5 hours, and then stirred in nitrogen at 15-30°C for 1-4 hours, and then distilled THF containing sodium halide sulfonate is added dropwise, and the reactant solution is refluxed at 40-80°C for 36-72 hours, and the end point is determined by thin layer chromatography; after natural cooling to room temperature, THF is removed from the product mixture using a rotary evaporator under vacuum, and then the product is separated by column chromatography to obtain a sulfonate-type fluorosurfactant; and the raw materials are calculated in parts by weight as follows: Na 0.05-1 part, THF distillate 10-300 parts, fluoroalkyl alcohol ether 0.5-75 parts, and sodium halide sulfonate 0.25-30 parts.

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