Method for intelligently regulating and controlling solubility of anionic surfactant-zwitterionic surfactant mixture in engine mode

Abstract

The invention provides a method for intelligently regulating and controlling the solubility of an anionic surfactant-zwitterionic surfactant mixture in an engine mode, which comprises the following steps: by taking a selenium-containing zwitterionic surfactant 3-tetradecyl selene-1-propane sulphobetaine (C14SeSB) as an engine, carrying out H2O2 oxidation and Na2SO3 reduction reaction to obtain a selenium-containing zwitterionic surfactant mixture; the soluble reversible stress intelligent response of the mixture of the C14SeSB and the anionic surfactant sodium dodecyl sulfate (C12SS) is driven, and the high-efficiency recovery and reutilization of the mixture of the C14SeSB and the C12SS at the recovery rate of not less than 97.3% can be realized. The technology provided by the invention can realize intelligent reversible regulation and control of the solubility of the mixture of the zwitterionic surfactant and the anionic surfactant. According to the technology disclosed by the invention, the Krafft temperature of the mixture of the zwitterionic surfactant and the anionic surfactant can be cyclically regulated and controlled for multiple times. The method is simple in technical equipment requirement, low in energy consumption and low in economic cost.

Description

Technical Field

[0001] The invention relates to the regulation of the solubility of a surfactant mixture and belongs to the field of fine chemical industry. Background Art

[0002] Daily chemical products such as toothpaste, facial cleanser, laundry detergent, and cosmetics often contain a large amount of surfactants. Not only that, surfactants have penetrated into various fields of life, but with the large-scale use of surfactants, the random discharge after use has caused increasingly serious environmental pollution problems. Among the large-scale use of surfactants, the use of ionic surfactants occupies a dominant position, so improving the use efficiency of ionic surfactants is an effective means to control the environmental pollution of surfactants.

[0003] The solubility of ionic surfactants in aqueous solutions is significantly dependent on temperature. When the temperature reaches a certain value, the solubility of ionic surfactants suddenly increases. This temperature is a unique property of ionic surfactants and is called the Krafft temperature (K T , °C). When the temperature is less than K T When the temperature is higher than K, its solubility suddenly decreases; and whether some of the listed interfacial activities of ionic surfactants can be manifested depends on their solubility in aqueous solution. T When the temperature is lower than K, the solubility of ionic surfactants in aqueous solution is much greater than cmc, and they can exert a series of surface activities, such as cleaning, foaming, emulsification, solubilization, etc. T , the solubility of ionic surfactants in water is greatly reduced, resulting in a concentration far below the cmc. At the same time, ionic surfactants precipitate from aqueous solution in the form of crystals, which facilitates the recovery of surfactants. If the K of ionic surfactants can be reversibly adjusted T, which can realize the normal use of ionic surfactants and their recycling. The inventors have reported redox-triggered "precipitation-dissolution" switch surfactants (Langmuir, 2020, 36, 3514−3521). "Precipitation-dissolution" switch surfactants are also a type of switch surfactants. The principle is that when the surfactant is in a dissolved state, it can normally exert its surface activity, emulsification, foaming, solubility and other properties. When the surfactant is in a precipitated state, it cannot normally exert its surface activity, emulsification, foaming, solubility and other properties. More importantly, when the "precipitation-dissolution" switch surfactant is in the "precipitation" state when it is in the off state, it provides the recovery and reuse of surfactants with the characteristics of easy separation and recycling that other types of switch surfactants do not have. However, the technology reported in the literature (Langmuir, 2020, 36, 3514−3521) has two limitations. First, they are all for a single selenium-containing surfactant. Second, it is not yet known whether it is applicable to a mixed surfactant system. Currently, many surfactant-based products contain two or more surfactants, and there is still a lack of efficient recovery of surfactant mixtures. To this end, the present invention proposes an engine-type intelligent control method for the solubility of anionic surfactant-zwitterionic surfactant mixtures, using a selenium-containing zwitterionic surfactant 3-tetradecylseleno-1-propanesulfonyl betaine (C 14 SeSB) is the engine, which drives C 14 SeSB and anionic surfactant sodium dodecyl sulfate (C 12 SS) mixture solubility stress intelligent response, can achieve C 14 SeSB and C 12 High-efficiency recovery and reuse of SS mixture. Compared with the prior art, the most distinctive difference of the present invention is that the present invention can realize the separation of selenium-containing switch surfactants and traditional high-K T Intelligent regulation of the solubility of anionic surfactant mixtures, rather than being applicable only to a single switch surfactant system as in the literature (Langmuir, 2020, 36, 3514−3521). The significant advantage of the technology of the present invention is that a method for intelligently regulating the solubility of anionic surfactant-zwitterionic surfactant mixtures by an engine-type can achieve efficient recovery and reuse of the two surfactants in the anionic surfactant-zwitterionic surfactant mixture. The selenium-containing zwitterionic surfactant used in the present invention, 3-tetradecylseleno-1-propanesulfonyl betaine (C 14 SeSB and anionic surfactant sodium dodecyl sulfate (C 12 The molecular structure of SS) is as follows 3-Tetradecylseleno-1-propanesulfobetaine (C 14 SeSB), Sodium dodecyl sulfate (C12SS). Summary of the invention

[0004] For the existing surfactant K T Reversible control technology is not enough to effectively control the solubility of surfactant mixtures and cannot achieve the shortcomings of surfactant mixture recovery. The present invention proposes an engine-type intelligent control method for the solubility of anionic surfactant-zwitterionic surfactant mixtures, using selenium-containing zwitterionic surfactant 3-tetradecyl selenium-1-propane sulfonyl betaine (C 14 SeSB) is the engine, which drives C 14 SeSB and anionic surfactant sodium dodecyl sulfate (C 12 SS) mixture solubility stress intelligent response, can achieve C 14 SeSB and C 12 High efficiency recovery and reuse of SS mixtures.

[0005] Furthermore, the selenium-containing zwitterionic surfactant 3-tetradecylseleno-1-propanesulfonyl betaine (C 14 SeSB) is an engine, which is characterized by C 14 SeSB and anionic surfactant sodium dodecyl sulfate (C 12 SS) mixture (C 14 SeSB-C 12 SS mixture) 14 The amount of substance of SeSB (n C14SeSB ) accounts for C 14 SeSB and C 12 The total amount of SS (n C14SeSB-C12SS ) is in the range of 0.2~0.9, preferably in the range of 0.3~0.5, and most preferably in the range of 0.5.

[0006] Furthermore, the reversible redox reaction is characterized in that H2O2 is used as an oxidant to 14 SeSB is oxidized to 3-tetradecylselenosulfoxide-1-propanesulfobetaine (C 14 SeOSB), and then Na2SO3 was used as a reducing agent to reduce C 14 Reduction of SeOSB to C 14 SeSB, oxidation reaction according to the amount of H2O2 (n H2O2 ) is n C14SeSBThe amount of H2O2 is determined by 1.1 times of the amount of Na2SO3 in the reduction reaction (n Na2SO3 ) is n H2O2 Determine the amount of Na2SO3 by 1 times.

[0007] Furthermore, the driving C 14 SeSB and anionic surfactant sodium dodecyl sulfate (C 12 The solubility stress intelligent response of the SS) mixture is characterized in that after the oxidation reaction with H2O2 as the oxidant is completed, C 14 SeSB-C 12 K of SS mixture T The temperature of the reactor is significantly reduced, and the lowest temperature can be reduced to about 0°C. After the reduction reaction with Na2SO3 as the reducing agent is completed, C 14 SeSB-C 12 K of SS mixture T It increases significantly above 25°C.

[0008] Furthermore, the C 14 SeSB and C 12 The high-efficiency recovery and reuse of SS mixture is characterized in that after the reduction reaction with Na2SO3 as the reducing agent is completed, C 14 SeSB-C 12 K of SS mixture T Increased significantly above 25°C, C 14 SeSB-C 12 The recovery rate of the SS mixture is not less than 97.3%. After the recovered surfactant mixture is oxidized by H2O2, it can be completely dissolved at room temperature and can function normally as a surfactant.

[0009] The method of the present invention has the following advantages over the prior art: 1. The technology of the present invention can realize intelligent reversible regulation of the solubility of a mixture of zwitterionic surfactants and anionic surfactants.

[0010] 2. The technology of the present invention can be used to determine the K of a mixture of zwitterionic surfactants and anionic surfactants. T Perform multiple cycles of regulation.

[0011] 3. The technology of the present invention can efficiently recycle and reuse the mixture of zwitterionic surfactants and anionic surfactants.

[0012] 4. The technical equipment requirements of the present invention are simple, the energy consumption is low and the economic cost is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 C obtained in Example 1 of the present invention 14 SeSB 1 H NMR spectrum.

[0014] Figure 2 C obtained in Example 1 of the present invention 14 FT-IR spectrum of SeSB.

[0015] Figure 3 For the H2O2 oxidation regulation of C in Examples 2 and 3 of the present invention 14 SeSB-C 12 K of SS mixture T .

[0016] Figure 4 C in Example 3 of the present invention 14 SeSB-C 12 SS mixture before and after H2O2 oxidation 77 Se NMR spectrum.

[0017] Figure 5 The Na2SO3 reduction in Example 4 of the present invention regulates C 14 SeSB-C 12 K of SS-Ox mixture T .

[0018] Figure 6 The redox cycle regulation C in Example 5 of the present invention 14 SeSB-C 12 K of SS mixture T . DETAILED DESCRIPTION

[0019] The following is a specific embodiment of the present invention to provide a method for intelligently controlling the solubility of anionic surfactant-zwitterionic surfactant mixture by engine type, using selenium-containing zwitterionic surfactant 3-tetradecylseleno-1-propanesulfobetaine (C 14 SeSB) is the engine, which drives C 14 SeSB and anionic surfactant sodium dodecyl sulfate (C 12 SS) mixture solubility stress intelligent response, can achieve C 14 SeSB and C 12 The effect of high-efficiency recovery and reuse of SS mixture is further illustrated.

[0020] Example 1: 3-Tetradecylseleno-1-propanesulfonyl betaine (C 14 Synthesis of SeSB This example mainly describes the selenium-containing zwitterionic surfactant 3-tetradecylseleno-1-propane sulfobetaine (C 14 The synthesis method of SeSB).

[0021] The first step is the synthesis of dodecyl diselenide. The synthesis route is as follows: .

[0022] Weigh 30.00 g (0.384 mol) of selenium powder and 90 mL of THF into a 1000 mL three-necked flask, stir at room temperature for 30 min, add 19.68 g (0.492 mol) of NaOH dispersed in 90 mL of THF, and stir in an ice bath for 10 min. Use a constant pressure dropping funnel to slowly drip (0.5 d / s) 9.19 g (0.156 mol, effective content) of hydrazine hydrate dispersed in 120 mL of THF, react for 2 h, and use a constant pressure dropping funnel to drip 116.46 g (0.42 mol) of 1-bromotetradecane and 120 mL of THF. After the addition is complete, remove the ice bath and react at room temperature for 12 h to obtain a crude product.

[0023] Filter and rotary evaporate to remove solid impurities and solvents, add appropriate amount of deionized water and dichloromethane (CH2Cl2) to extract and separate the liquids, take the dichloromethane phase, dry it with anhydrous sodium sulfate, recrystallize it with ethyl acetate (EA) for 3 times, and dry it in vacuum to obtain yellow needle-shaped solid diselenide with a yield of 82.5%.

[0024] In the second step, 3-tetradecyl selenol-1-propane alcohol (C 14 The synthesis of SeC3OH) is as follows .

[0025] Weigh 20.00 g (36.18 mmol) C 14 DSe was placed in a 500 mL three-necked round-bottom flask, and 150 mL THF was added. In N2 atmosphere, 6.85 g (181.13 mmol) NaBH4 in 75 mL deionized water was slowly added dropwise using a constant pressure dropping funnel under ice bath conditions. After the addition was complete, the reaction was carried out at room temperature until the system turned completely white. Finally, a mixture of 100 mL THF and 11.08 g (79.72 mmol) Br(CH2)3OH was added dropwise and the reaction was carried out at room temperature for 24 h.

[0026] After the reaction was completed, the solvent was removed by rotary evaporation, water and dichloromethane were added to extract the liquid, the dichloro phase was taken and the solvent was removed by rotary evaporation under reduced pressure, and finally recrystallization was performed three times with petroleum ether to obtain a white product 3-tetradecylseleno-1-propanol (C14 SeC3OH) is about 14.11 g, with a yield of 89.9%.

[0027] The third step is toluenesulfonic acid tetradecyl selenopropyl ester (C 14 The synthesis of SeC3OTs) is as follows .

[0028] Weigh 6.70 g (20 mmol) C 14 SeC3OH, 0.25 g (2 mmol) catalyst 4-dimethylaminopyridine (DMAP) and 6.86 g (66.67 mmol) of acid-binding agent triethylamine were placed in a 500 mL three-necked round-bottom flask, 140 mL of dichloromethane was added and stirred thoroughly, 5.32 g (27.93 mol) of TsCl dissolved in 95 mL of dichloromethane was measured and slowly added dropwise using a separatory funnel, and the reaction was allowed to react at room temperature for 12 h.

[0029] After the reaction, dichloromethane was added to extract the liquid, the dichloro phase was taken, dried over anhydrous sodium sulfate to remove water, and then dried under reduced pressure. Column chromatography was performed using a developing solvent of petroleum ether: ethyl acetate = 10:1, and the product toluenesulfonic acid tetradecyl selenopropyl ester (C 14 SeC3OTs), with a yield of about 91.7%.

[0030] Step 4: 3-tetradecyl selenium-1-propylamine (C 14 The synthesis of SeC3AM) is as follows

[0031] Weigh 28.50 g (58.21 mmol) of crude product C 14 SeC3OTs was placed in a 1000 mL three-necked round-bottom flask, 500 mL of ethanol was added, and the mixture was stirred thoroughly. 52.49 g (1164.20 mmol) of an effective dimethylamine aqueous solution was added, and the mixture was reacted at 25 °C for 24 h. After the reaction was completed, the mixture was evaporated by rotary evaporation and separated by column chromatography using ethyl acetate as the developing solvent to obtain yellow oily 3-tetradecylseleno-1-propylamine (C 14 1%。 SeC3AM) 8.60 g, yield 57.1%.

[0032] The fifth step, 3-tetradecyl selenium-1-propane sulfobetaine (C 14 The synthesis of SeSB) is as follows .

[0033] Weigh 5.00 g (13 mmol) C 14 SeC3AM was placed in a 500 mL three-necked round-bottom flask, 200 mL of acetone was added, and the mixture was stirred thoroughly. 2.03 g (16 mmol) of 1,3-propanesulfone was weighed and dissolved in acetone and added to the reaction system. White particles appeared during the reaction and the reaction lasted for 24 h. After the reaction was completed, the white solid was filtered out by suction, and the filtrate was allowed to stand to allow the white precipitate to continue to precipitate. The white solid was then filtered out by suction and washed with acetone several times, filtered and dried to obtain white powdery particles of 3-tetradecylseleno-1-propanesulfobetaine (C 14 SeSB) 5.10 g, yield 76.3%.

[0034] Product C 14 SeSB 1 H NMR spectra and FT-IR spectra are shown in Figure 1 and Figure 2 . Configure C with a mass percentage of 0.2% 14 SeSB aqueous solution, heated to boiling, C 14 SeSB was not completely dissolved, so C 14 SeSB's K T Over 90°C.

[0035] Example 2: C 14 SeSB-C 12 K of SS mixture T This embodiment mainly describes C 14 SeSB-C 12 K of SS mixture T With C 14 SeSB-C 12 The relationship between the composition of the SS mixture. 14 SeSB and C 12 SS is expressed in molar ratio (n C14SeSB / n C12SS ) are 0:1, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, and 1:0, respectively, to prepare C 14 SeSB-C 12 The mass percentage concentration of the SS mixture is 1.0% aqueous solution. After the mixed system is heated to completely dissolve, it is precipitated at 0~4℃ and K is determined by visual method. T The experiment was repeated three times, and the experimental results are shown in Figure 3 . C 12 SS K T is about 36.8°C, due to C 14 SeSB's K TOver 90°C, so Figure 3 90°C is denoted as C 14 SeSB's K T For C 14 SeSB and C 12 SS is expressed in molar ratio (n C14SeSB / n C12SS ) are 0:1, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, and 1:0 systems, respectively. 14 The molar ratio of SeSB (n C14SeSB / n C14SeSB-C12SS ) are 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 respectively. Figure 3 The results show that C 14 SeSB-C 12 K of SS mixture T All above 30°C.

[0036] Example 3: Engine-type regulation of C under H2O2 oxidation 14 SeSB-C 12 K of SS mixture T According to Example 2 C14SeSB / n C14SeSB-C12SS ratio, configuration C 14 SeSB-C 12 SS mixture aqueous solution, C 14 SeSB-C 12 The mass percentage concentration of the SS mixture is 1.0%. 14 The amount of substance in SeSB is expressed in terms of n C14SeSB 1.1 times of H2O2 was added, and after the oxidation reaction was completed, the resulting system (denoted as C 14 SeSB-C 12 SS-Ox) was placed in -10℃ and fully frozen until crystals precipitated out of the system, and then K was determined by visual method. T The experiment was repeated three times, and the results are shown in Figure 3 .Depend on Figure 3 The results show that n C14SeSB / n C14SeSB-C12SS For a system with a value of 0, K before and after oxidation T There is no significant change, all about 36.8°C, this is because n C14SeSB / n C14SeSB-C12SS The system with a value of 0 is essentially composed of only C 12 SS is a surfactant; C14SeSB / n C14SeSB-C12SSFor a system with a value of 1.0, K before and after oxidation T There is a significant change, from 90°C before oxidation to 0°C, this is because n C14SeSB / n C14SeSB-C12SS The system with a value of 1.0 actually only has C 14 SeSB is a surfactant that forms C 14 SeOSB ( Figure 4 ), namely C 14 K of SeOSB T About 0°C; for n C14SeSB / n C14SeSB-C12SS In the range of 0.1~0.9, C 14 SeSB-C 12 SS-Ox K T In the range of 0~34.1°C, it can be seen that the surfactant C 14 Oxidation of SeSB to C 14 SeOSB ( Figure 4 ) and then drive C 14 SeSB-C 12 SS-Ox K T There is a significant reduction effect. According to K T Whether to reduce to 25°C or below, preferably n C14SeSB / n C14SeSB-C12SS The range is 0.3~0.9. According to the principle of using as little special surfactant as possible, the preferred n C14SeSB / n C14SeSB-C12SS The range is 0.3~0.5, according to K T The principle of using as little special surfactant as possible when the minimum value is reached is the most preferred n C14SeSB / n C14SeSB-C12SS The value is 0.5.

[0037] Figure 4 C 14 SeSB-C 12 C in SS mixture 14 SeSB and C 14 SeSB-C 12 SS-Ox C 14 SeOSB 77 Se NMR spectrum.

[0038] Example 4: Engine-type regulation C under Na2SO3 reduction 14 SeSB-C 12 K of SS-Ox mixture T This example mainly illustrates the engine-type regulation of C under the reduction of Na2SO3 14 SeSB-C 12 K of SS-Ox mixture T The effect of C 14 SeSB-C 12 The SS-Ox mixture samples were prepared according to the method described in Example 3. According to the amount of Na2SO3 (n Na2SO3 ) is n H2O2 The amount of Na2SO3 is determined by 1 times of the original amount. After the reduction reaction is completed, the resulting system (referred to as C 14 SeSB-C 12 SS-Re) was placed in -10℃ and fully frozen until crystals precipitated out of the system, and then K was determined by visual method. T The experiment was repeated three times, and the results are shown in Figure 5 .

[0039] Depend on Figure 5 The results show that the C 14 SeSB-C 12 SS-Re K T With C 14 SeSB-C 12 SS system, it can be seen that under the engine-like regulation of Na2SO3 reduction, C 14 SeSB-C 12 K of SS-Ox mixture T This is because the Na2SO3 reduction reaction has significantly increased the 14 Reduction of SeOSB to C 14 SeSB ( Figure 4 ), thereby driving C 14 SeSB-C 12 SS-Re K T Increase. For n C14SeSB / n C14SeSB-C12SS For a system with a value of 0, K before and after reduction T The value does not change much, because there is no C in the sample with this composition. 14 SeSB or C 14 SeOSB; for n C14SeSB / n C14SeSB-C12SS For a system with a value of 1.0, K T The value changes the most, because the sample with this composition has only C 14 SeSB (or C 14 SeOSB) is a surfactant; for n C14SeSB / n C14SeSB-C12SS In the range of 0.1~0.9, C 14SeSB-C 12 SS-Ox K T , after being reduced by Na2SO3, there was a significant increase.

[0040] Example 5: Redox reversible regulation of C 14 SeSB-C 12 K of SS mixture T This embodiment mainly describes C 14 SeSB-C 12 K of SS mixture T After the effect of oxidation (H2O2 as oxidant) and reduction (Na2SO3 as reductant) cycle regulation, the C 14 SeSB-C 12 The material composition ratio in the SS mixture is n C14SeSB / n C14SeSB-C12SS is 0.5, sample configuration, oxidation, reduction and K T The methods and reaction conditions of the determination steps were carried out according to the relevant methods in the above-mentioned selected examples 2 to 4, and the experimental results are shown in Figure 6 .Depend on Figure 6 It can be seen that C 14 SeSB-C 12 K of SS mixture T After H2O2 oxidation, K T At around 0℃, after reduction by Na2SO3, K T At around 35.5℃, this cycle of regulation can be performed at least 5 times.

[0041] Example 6: C 14 SeSB-C 12 Recycling and reuse of SS mixtures The C used in this example 14 SeSB-C 12 The preparation method and oxidation-reduction method of the aqueous solution sample of the SS mixture are the same as those in Examples 3 to 5. 14 SeSB-C 12 SS mixture C14SeSB / n C14SeSB-C12SS The values ​​of C and D were 0.3, 0.4, 0.5 and 0.6 respectively. After being oxidized completely by H2O2, all sample aqueous solutions were clear and transparent at room temperature. When stained with chlorinated pinacol cyanol, all sample solutions were blue, indicating that micelles existed in all sample solutions. After adding Na2SO3 for full reduction, all solutions showed precipitation. After precipitation was complete, the filtrate was filtered, vacuum dried, and weighed to calculate C and D respectively. 14 SeSB-C 12The recoveries of the SS mixture were 97.4±0.1%, 97.7±0.2%, 98.4±0.1% and 98.2±0.1%, respectively. 14 SeSB-C 12 The recovery rate of SS mixture was no less than 97.3%, and the recovery effect was good.

[0042] The recovered C 14 SeSB-C 12 The SS mixture is reconfigured to have a mass percentage content of 1.0%, n C14SeSB / n C14SeSB-C12SS The aqueous solutions of 0.3, 0.4, 0.5 and 0.6 respectively, after being completely oxidized by H2O2, all the sample aqueous solutions were clear and transparent at room temperature. They were stained with chlorinated pinacol cyanol and all the sample solutions were blue, indicating that micelles existed in all the sample solutions. T The values ​​are Figure 3 Corresponding to n C14SeSB / n C14SeSB-C12SS System K T The numerical values ​​are consistent, indicating that the C 14 SeSB-C 12 The quality of SS mixture is better.

[0043] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Any person familiar with the present invention can easily change or replace the components after the present invention is disclosed, and all technical improvements that do not depart from the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for intelligently controlling the solubility of anionic surfactant-zwitterionic surfactant mixture by engine type, characterized in that: Using 3-tetradecylseleno-1-propane sulfobetaine as the engine, the solubility stress intelligent response of the mixture of 3-tetradecylseleno-1-propane sulfobetaine and the anionic surfactant sodium dodecyl sulfate is driven by the reversible redox reaction, thereby achieving efficient recovery and reuse of the mixture of 3-tetradecylseleno-1-propane sulfobetaine and sodium dodecyl sulfate.

2. The method according to claim 1, characterized in that The ratio of the amount of 3-tetradecylseleno-1-propane sulfobetaine in the mixture of 3-tetradecylseleno-1-propane sulfobetaine and sodium dodecyl sulfonate to the total amount of the substance is in the range of 0.2 to 0.9, preferably in the range of 0.3 to 0.5, and most preferably 0.

5.

3. The method according to claim 1, characterized in that The redox reversible reaction refers to the oxidation of 3-tetradecylselenium-1-propane sulfobetaine to 3-tetradecylselenium sulfoxide-1-propane sulfobetaine using H2O2 as an oxidant, and then the reduction of 3-tetradecylselenium sulfoxide-1-propane sulfobetaine to 3-tetradecylselenium sulfoxide-1-propane sulfobetaine using Na2SO3 as a reducing agent.

4. The method according to claim 3, characterized in that During the oxidation reaction, the amount of H2O2 is determined based on the amount of H2O2 being 1.1 times that of 3-tetradecylseleno-1-propanesulfobetaine, and during the reduction reaction, the amount of Na2SO3 is determined based on the amount of Na2SO3 being 1 times that of H2O2.

5. The method according to claim 1, characterized in that After the oxidation reaction with H2O2 as the oxidant is completed, the K T It can be reduced to 0°C. After the reduction reaction with Na2SO3 as the reducing agent is completed, the K T May increase to 25°C and above.

6. The method according to claim 1, characterized in that The recovery rate of the mixture of 3-tetradecylseleno-1-propanesulfobetaine and sodium dodecylsulfonate is not less than 97.3%. The recovered surfactant mixture can be converted into a surfactant that can be completely dissolved at room temperature and can normally perform the surfactant function after being oxidized by H2O2.

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