Sulfonate type fluorosurfactant with excellent degradability and emulsifying performance and preparation method thereof

Abstract

The invention provides a sulfonate type fluorinated surfactant with excellent degradability and emulsifying performance and a preparation method thereof, and relates to the field of fine chemical synthesis. According to the sulfonate type fluorine surfactant, firstly, halogenated fluoroalkane and fluoroolefin are subjected to a free radical polymerization reaction under the action of an initiator, methylene is introduced into a hydrophobic tail, biodegradation or enzymatic degradation can be conducted, and harm to a human body and ecological environment pollution are reduced; then replacing halogen atoms with hydroxyl under the heating condition of a sodium hydroxide aqueous solution, then carrying out ring-opening polymerization reaction with alkylene oxide to introduce alkoxy to increase the hydrophilicity of the surfactant, finally substituting hydrogen atoms in alcoholic hydroxyl with sodium, and then reacting with halogenated sodium sulfonate to introduce a sodium sulfonate group as a head group; the surface tension and the critical micelle concentration are lower.

Description

Technical Field

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

[0002] Fluorosurfactants are surfactants with fluorocarbon chains as non-polar groups, that is, 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, which allows 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, and it is one of the covalent bonds with the highest known bond energy. Therefore, fluorosurfactants have good thermal and chemical stability, and can stably exist and function under harsh conditions such as high temperature, strong acid, strong alkali, and strong oxidizing media. Fluorine atoms are very difficult to polarize, making the polarity of fluorocarbon chains smaller than that of hydrocarbon chains, which helps fluorosurfactants to aggregate and arrange into molecular films at the liquid / gas interface, thereby further reducing surface tension.

[0003] However, some components in fluorosurfactants, such as perfluorooctane sulfonic acid (PFOS) and its derivatives, are persistent in the environment and in organisms and are not easily degraded. These substances can accumulate in organisms and be transmitted through the food chain, causing long-term impacts on ecosystems. Due to the special properties of fluorosurfactants, they can migrate in the atmosphere, water bodies, and soil, and even cross national borders, posing a threat to the global environment. Under high temperature or strong acid and alkali environments, some fluorosurfactants may decompose and produce toxic gases, causing direct harm to the human body. People who are 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 organisms and terrestrial ecosystems.

[0004] Among fluorosurfactants, if the carbon fluorine chain is long, it is difficult to degrade, which will have an adverse effect on environmental safety and human health. Therefore, people have always been committed to finding suitable alternative products. However, in the process of synthesizing these alternatives, most methods have encountered problems such as poor water solubility, insufficient surface emulsification performance, and difficulty in degradation. Studies have shown that the degradability of fluorosurfactants can be enhanced by adding "weak sites" such as methyl (CH) or methylene (CH2) to the hydrophobic tail. These "weak sites" can be decomposed by organisms or enzymes, so that the long carbon fluorine chains that are difficult to degrade are decomposed into short carbon fluorine chains with low bioaccumulation. At the same time, ethoxy and sulfonic acid groups are introduced to reduce the surface tension of the surfactant, so that it can form micelles at lower concentrations, thereby improving the emulsification performance of the surfactant. Therefore, it is of great significance to develop a degradable sulfonate-type fluorosurfactant with excellent emulsification performance and its preparation method. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a sulfonate-type fluorine surfactant with excellent emulsification performance and a preparation method thereof. First, a halogenated fluoroalkane and a fluoroolefin are subjected to a free radical polymerization reaction under an initiator to introduce methylene groups in the hydrophobic tail, and these methylene groups can be biodegraded or enzymatically degraded. Subsequently, the halogen atoms are replaced by hydroxyl groups under heating conditions of a sodium hydroxide aqueous solution, and then an alkoxy group is introduced by a ring-opening polymerization reaction with an alkylene oxide to increase the hydrophilicity of the surfactant. Finally, the hydrogen atoms in the alcoholic hydroxyl group are replaced by 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 degradable sulfonate-type fluorosurfactant with excellent emulsification performance, 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 the 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 under the action of an initiator to introduce a methylene group into the hydrophobic tail to prepare a methylene-containing halogenated fluoroalkane, wherein the components are calculated by weight as follows: 1-24 parts of the initiator, 0.5-50 parts of the fluoroolefin, and 0.25-100 parts of the halogenated fluoroalkane;

[0011] (2) Preparation of fluoroalkanols and fluoroalkanol ethers: the above-mentioned methylene-containing halogenated fluoroalkanes are subjected to heating 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 alcohol ether is replaced with sodium, and then reacted with sodium halide sulfonate to introduce a sodium sulfonate group as a head group to obtain a 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, and C6F13I.

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

[0016] Preferably, the specific operation of step (1) is as follows: after high-pressure sterilization and nitrogen purging, the initiator, fluoroolefin and halogenated fluoroalkane are added to an autoclave under vacuum, and reacted 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.

[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 and cyclohexane oxide.

[0018] Preferably, the specific operation of step (2) is: reacting the methylene-containing halogenated fluoroalkane in step (1) in a sodium hydroxide aqueous solution at 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.

[0019] Preferably, the sodium halide sulfonate in step (3) is at least one of sodium 2-chloroethylsulfonate and sodium 2-bromoethylsulfonate.

[0020] Preferably, 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. 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. Subsequently, 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 at 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 by weight as follows: Na 0.05-1 part, THF distillate 10-300 parts, fluoroalkyl alcohol ether 0.5-75 parts, sodium halide sulfonate 0.25-30 parts.

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

[0022] (1) The sulfonate-type fluorinated surfactant prepared by the present invention has methylene units introduced 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, the branched hydrophobic tail can be used to replace the straight hydrophobic tail to prevent the influence 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] Fig. 9is the H NMR spectrum of the intermediate and product of reaction formula VIII in Example 3;

[0034] Fig.10 is the H NMR spectrum of the intermediate and product of reaction formula IX in Example 3;

[0035] Fig.11 The H NMR spectra of the intermediate and product of reaction formula X in the comparative example are shown in FIG. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Embodiment 1:

[0038] Preparation of sulfonate type fluorosurfactant:

[0039] 1. Preparation of iodofluoroalkanes containing methylene:

[0040] After 20 minutes of high pressure sterilization and 30 bar of nitrogen pressure purge, the autoclave was placed under vacuum, and 6.70 g of initiator tert-butyl peroxypivalate, 6.40 g of vinylidene fluoride and 12.30 g of pentafluoroiodoethane were added, and the reaction was carried out 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, 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 iodofluoroalkane, and the reaction equation is as follows:

[0041]

[0042] Depend on Figure 2 The H-NMR spectrum showed that there was an absorption peak at 3.1ppm and 3.2ppm, 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 in step 1 was reacted in a sodium hydroxide aqueous solution at 40° C. for 1 hour to obtain a fluoroalkanol; then the mixture was transferred to a high-pressure reactor, 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 a The hydrogen spectrum shows that 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 3.6-3.8 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] 1.50g of Na and 50mL of (tetrahydrofuran) THF distillate were placed in a 500mL flask in turn and mixed for 30 minutes, and then a solution containing 17.60g of the fluoroalkyl alcohol ether obtained in step 2 and 100ml of distilled THF was added drop by drop to the ice bath flask. After the addition process was completed, the reaction continued in the ice bath for 4 hours, and then stirred in nitrogen at 25°C for 2 hours. Subsequently, 100mL of distilled THF containing 7.69g of sodium 2-chloroethylsulfonate was dripped in, and the reactant solution was refluxed at 65°C for 60h, and 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 then the product was separated by column chromatography to obtain a sulfonate-type fluorosurfactant, and the reaction equation is as follows:

[0049]

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

[0051] Embodiment 2:

[0052] Preparation of sulfonate type fluorosurfactant:

[0053] 1. Preparation of bromofluoroalkanes containing methylene:

[0054] After 20 minutes of high pressure 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 the reaction was carried out 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, 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, and the reaction equation is as follows:

[0055]

[0056] Depend on Figure 5 As shown in the H-NMR spectrum, there are 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 in step 1 was reacted in a sodium hydroxide aqueous solution at 40° C. for 1 hour to obtain a fluoroalkanol; then the mixture was transferred to a high-pressure reactor, 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 a The hydrogen spectrum shows that 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 (1,1,1,6,6,6-hexafluoro-4-(trifluoromethyl)hexan-2-yl)oxy)propan-2-yl)oxy)propan-2-ol is obtained.

[0061] 3. Preparation of sulfonate type fluorosurfactant:

[0062] 1.50g of Na and 50mL of (tetrahydrofuran) THF distillate were placed in a 500mL flask in turn and mixed for 30 minutes, and then a solution containing 24.50g of the fluoroalkyl alcohol ether obtained in step 2 and 70ml of distilled THF was added drop by drop to the ice bath flask. After the addition process was completed, the reaction continued for 3 hours in the ice bath, and then stirred for 1.5 hours in nitrogen at 25°C. Subsequently, 70mL of distilled THF containing 8.88g of sodium 2-bromoethylsulfonate was dripped in, and the reactant solution was refluxed at 60°C for 48h, and 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 then the product was separated by column chromatography to obtain a sulfonate-type fluorosurfactant, and the reaction equation is as follows:

[0063]

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

[0065] Embodiment 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 15.33 g of initiator cyclohexyl tert-butyl peroxydicarbonate, 14.41 g of trifluoropropylene and 7.45 g of trifluoroiodomethane were added, and the reaction was carried out 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, 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, and the reaction equation is as follows:

[0069]

[0070] Depend on Figure 8As shown in the H NMR spectrum, there are 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 in step 1 was reacted in a sodium hydroxide aqueous solution at 40° C. for 1 hour to obtain a fluoroalkanol; then the mixture was transferred to a high-pressure reactor, 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 Fig. 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. Fig. 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-pentahydroicosan-1-ol is obtained.

[0075] 3. Preparation of sulfonate type fluorosurfactant:

[0076] 1.50g of Na and 50mL of (tetrahydrofuran) THF distillate were placed in a 500mL flask in turn and mixed and stirred for 30 minutes, and then a solution containing 30.24g of the fluoroalkyl alcohol ether obtained in step 2 and 100ml of distilled THF was added drop by drop to the ice bath flask. After the addition process was completed, the reaction continued in the ice bath for 4 hours, and then stirred in nitrogen at 25°C for 1.5 hours. Subsequently, 100mL of distilled THF containing 7.69g of sodium 2-chloroethylsulfonate was dripped in, and the reactant solution was refluxed at 65°C for 72h, and 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 then the product was separated by column chromatography to obtain a sulfonate-type fluorosurfactant, and the reaction equation is as follows:

[0077]

[0078] Depend on Fig.10 a As shown in the hydrogen spectrum, 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)hex-2-yl)oxy)propoxy sodium is obtained. Fig.10As shown in b, due to the introduction of 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-hexaoxyheptadecanesulfonate.

[0079] Comparative Example 1:

[0080] Preparation of sulfonate type fluorosurfactant:

[0081] 1.50g of Na and 50mL of (tetrahydrofuran) THF distillate were placed in a 500mL flask and mixed for 30 minutes, and then 23.21g of 2-perfluorooctylethanol and 100ml of distilled THF solution were added drop by drop into the ice bath flask. After the addition process was completed, the reaction continued for 4 hours in the ice bath, and then stirred for 2 hours in nitrogen at 25°C. Subsequently, 100mL of distilled THF containing 7.69g of 2-chloroethylsulfonate was dripped in, and the reactant solution was refluxed at 65°C for 60h, and 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 then the product was separated by column chromatography to obtain a sulfonate-type fluorosurfactant. The reaction equation is as follows:

[0082]

[0083] Depend on Fig.11 a As shown in the hydrogen spectrum, 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-dodecyloxy sodium is obtained. Fig.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 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 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] It can be seen from the data in the table that 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. It can be seen from Comparative Example 1 that the equilibrium surface tension of the sulfonate surfactants in Examples 1-3 is less than that in Comparative Example 1, the critical micelle concentration is lower than that in Comparative Example 1, and the content of long-chain carbon fluorides in the biodegradation products is much less than that in Comparative Example 1, indicating that the comprehensive performance of the sulfonate surfactant 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 the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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 embodiments of the present invention.

Claims

1. A biodegradable sulfonate-type fluorosurfactant with excellent emulsification properties, 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 as claimed in 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 under the action of an initiator to introduce a methylene group into the hydrophobic tail to prepare a methylene-containing halogenated fluoroalkane, wherein the components are calculated by weight as follows: 1-24 parts of the initiator, 0.5-50 parts of the fluoroolefin, and 0.25-100 parts of the halogenated fluoroalkane; (2) Preparation of fluoroalkanols and fluoroalkanol ethers: the above-mentioned methylene-containing halogenated fluoroalkanes are subjected to heating 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 fluorosurfactant: The hydrogen atom in the alcoholic hydroxyl group of the above fluoroalkyl alcohol ether is replaced with sodium, and then reacted with sodium halide sulfonate to introduce a sodium sulfonate group as a head group to obtain a sulfonate type fluorosurfactant.

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

4. The preparation method according to claim 2, characterized in that: In the step (1), the halogenated fluoroalkane is at least one of CF3I, CF3Br, CF3Cl, C2F5I, C2F5Br, C2F5Cl, C3F7I, C3F7Br, C3F7Cl, C4F9I, and C6F13I.

5. The preparation method according to claim 2, characterized in that: 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, characterized in that: 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: The specific operation of step (1) is as follows: the alkylene oxide in step (2) is at least one of ethylene oxide, propylene oxide and cyclohexene oxide.

8. The preparation method according to claim 2, characterized in that: 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, characterized in that: 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, 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 the ice bath flask. After the addition process is completed, the reaction is continued in the ice bath for 2-5 hours, and then stirred in nitrogen at 15-30° C. for 1-4 hours. Subsequently, distilled THF containing sodium halide sulfonate is added dropwise, 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 at room temperature, THF is removed from the product mixture by 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 by weight as follows: Na 0.05-1 part, THF distillate 10-300 parts, fluoroalkyl alcohol ether 0.5-75 parts, sodium halide sulfonate 0.25-30 parts.

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