Safe preparation method, product and application of short fluorocarbon alkyl sulphobetaine surfactant

Abstract

The invention relates to the technical field of chemical material preparation, and particularly discloses a safe preparation method of a short fluorocarbon alkyl sulphobetaine surfactant, a product and application, and the safe preparation method comprises the following steps: (1) in a solvent system I, reacting epoxy chloropropane with secondary amine to obtain an intermediate 1; (2) in a solvent system II, reacting the intermediate 1 with sodium hydrosulfide or a hydrate thereof to obtain an intermediate 2; (3) reacting the intermediate 2 with short fluorocarbon alkyl iodide to obtain perfluoroalkyl thioether propyl tertiary amine; and (4) carrying out sulfonation treatment on perfluoroalkyl thioether propyl tertiary amine to obtain the short-fluorocarbon alkyl sulphobetaine surfactant. According to the invention, by designing a synthetic route without using a high-risk reagent, the safety and operability of the process are remarkably improved, and the sulphobetaine surfactant with excellent acid, alkali and salt chemical stability and excellent surface activity is successfully prepared; and a key material and a safe and reliable preparation process are provided for development of a new-generation efficient environment-friendly fire extinguishing agent.

Description

Technical Field

[0001] This invention relates to the field of chemical material preparation technology, and specifically discloses a safe preparation method, product, and application of a short-fluorocarbon alkyl sulfonyl betaine surfactant. Background Technology

[0002] Fluorocarbon surfactants are widely used in industrial fields such as fire protection, oil extraction, and coatings due to their extremely high surface activity, excellent thermal stability, and chemical inertness. Especially in aqueous film-forming foam (AFFF) fire extinguishing agents, fluorocarbon surfactants, as a key component, can rapidly spread and form a water film on the fuel surface, which also has the functions of isolating air and cooling, thereby achieving efficient fire extinguishing and preventing reignition.

[0003] To mitigate the persistent environmental risks of long-chain perfluorinated compounds (such as PFOA and PFOS), the industry is shifting towards developing environmentally friendly surfactants based on short fluorocarbon chains. Betaine-type amphoteric fluorocarbon surfactants have become a research hotspot due to their excellent compatibility and environmental compatibility. Among them, sulfobetaine, due to the strong acidity of its sulfonate group, can maintain a stable zwitterionic state over a wide pH range and in high electrolyte environments. Its chemical stability is significantly better than that of carboxybetaine, making it more promising for fire extinguishing applications in complex environments.

[0004] However, existing technologies for synthesizing short-fluorocarbon sulfobetaine still face severe challenges in terms of process safety and economy. For example, Chinese patent CN116144377A discloses a method for synthesizing fluorocarbon betaine using perfluorohexylethanol as a raw material. Although this method achieves a short-fluorocarbon chain structure, a key step requires the use of sodium hydride (NaH) as a strong base reagent. Sodium hydride reacts violently with water and is flammable and explosive, placing extremely high demands on production equipment, operational safety, and storage and transportation, greatly limiting the safe large-scale production of this technology. Another known synthetic route, such as patent US20110092735A1, uses perfluoroalkyl iodine as a starting material, but subsequent steps involve oxidation with highly toxic chlorine gas, which also poses significant safety and environmental risks. In addition, some processes, such as patent CN107903180A, suffer from poor atom economy, high levels of waste, and high costs due to the use of raw materials with low effective content or the need for multiple lengthy reactions.

[0005] Therefore, there is a need for a method to prepare short-fluorocarbon alkyl sulfobetaine that is safe, operates under mild conditions, and avoids the use of hazardous reagents. This method should reliably synthesize sulfobetaine products with excellent surface activity and stable chemical properties to meet the dual requirements of performance and safety / environmental friendliness in high-end foam fire extinguishing agents and other fields. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a safe preparation method, product, and application of short-fluorocarbon alkyl sulfonyl betaine surfactants. By designing a novel synthetic route that avoids the use of highly hazardous reagents such as sodium hydride and chlorine, the inherent safety and operability of the process are significantly improved. A novel short-fluorocarbon alkyl sulfonyl betaine was successfully prepared. This product combines the excellent acid, alkali, and salt chemical stability of sulfonyl betaine with the superior surface activity of fluorocarbon chains. When applied to aqueous film-forming foam fire extinguishing agents, it can significantly reduce the surface tension and interfacial tension of the extinguishing agent solution, providing a key material and a safe and reliable preparation process for the development of a new generation of high-efficiency and environmentally friendly fire extinguishing agents.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A safe preparation method of a short-fluorocarbon alkyl sulfonyl betaine surfactant, comprising the following steps:

[0008] (1) In solvent system I, epichlorohydrin reacts with a secondary amine to obtain intermediate 1;

[0009] (2) In solvent system II, intermediate 1 reacts with sodium hydrosulfide or its hydrate to obtain intermediate 2;

[0010] (3) Intermediate 2 reacts with a short-fluorocarbon alkyl iodine to give a perfluoroalkyl sulfide propyl tertiary amine; the structure of the short-fluorocarbon alkyl iodine is C n F 2n+1 -C m H 2m -I, where n is an integer from 2 to 6 and m is an integer from 1 to 8;

[0011] (4) The short-fluoroalkyl sulfonyl betaine surfactant is obtained by sulfonation of perfluoroalkyl sulfide propyl tertiary amine;

[0012] In each of the above reactions, R1 and R2 are independently C1-C4 alkyl groups, or R1 and R2 together form a C2-C6 carbocycloalkyl group or a carbocycloalkyl group containing oxygen / sulfur heteroatoms. Both ends of the carbocycloalkyl group are connected to the N atom to form a cyclic secondary amine structure, and R3 is H, OH or a C1-C3 alkyl group.

[0013] The core principle of this invention lies in the design of a four-step mild unit reaction based on the multifunctional reaction characteristics of epichlorohydrin, including the introduction of a tertiary amine center through epoxy ring opening, the introduction of a thiol group through nucleophilic substitution, the connection of a fluorocarbon chain through thioetherification, and the construction of a betaine structure through quaternization-sulfonation. This allows for the sequential construction of the target molecule's skeletal structure without the need for high-risk reagents such as sodium hydride and chlorine.

[0014] The chemical design principle begins with the use of epichlorohydrin as a key skeletal raw material. This molecule possesses both highly reactive epoxy groups and nucleophilically substituted chlorine atoms, providing ideal reaction sites for the subsequent targeted introduction of different functional groups. In the first step, under low-temperature conditions, the secondary amine selectively performs ring-opening nucleophilic attack on the epoxy group, generating the intermediate dimethylaminochloropropanol, which contains a tertiary amine center and a chlorine atom. This step is performed under mild conditions, avoiding a strongly alkaline environment, thus laying the foundation for the safety of the entire synthetic route.

[0015] Then, using sodium hydrosulfide as a mild nucleophile, the chlorine atom of intermediate 1 was nucleophilically substituted in the aqueous phase, efficiently converting it to a thiol group to obtain dimethylaminohydroxypropanethiol. This step achieved the key functional group conversion from chlorine to sulfur while preserving the hydroxyl and tertiary amine structures, preparing for the subsequent attachment of fluorocarbon chains.

[0016] The thiol group (-SH) of intermediate 2 acts as a strong nucleophilic center, undergoing a highly efficient nucleophilic substitution reaction with a short fluorocarbon alkyl iodide (Rf-AI) to form a stable thioether bond (-S-). This covalently links the amphiphilic short fluorocarbon chain with a hydrophilic nitrogen- or hydroxyl-containing segment, yielding a perfluoroalkyl thioether propyl tertiary amine. This reaction is conducted under mild conditions, with high feedstock utilization and minimal waste.

[0017] The final step involves constructing the betaine structure via a quaternization-sulfonation reaction. The tertiary amine nitrogen atom of the perfluoroalkyl thioether propyl tertiary amine acts as a nucleophilic center, reacting with the sulfonating agent to form an inner salt structure, thereby introducing a highly hydrating and stable sulfonate anion (-SO32-). - The final product, short-fluoroalkyl sulfobetaine, is formed.

[0018] The core design principle of the entire synthetic route lies in obtaining a complex zwitterionic structure with a short fluorocarbon hydrophobic chain, a thioether linker arm, a tertiary amine center, and a sulfonate hydrophilic head through epichlorohydrin ring-opening, nucleophilic substitution of the chlorine atom, thioether bond formation, and quaternization steps, without the need for extreme conditions such as the use of alkali metal hydrides. This achieves highly efficient synthesis of the target molecule structure under the premise of high safety.

[0019] Furthermore, the secondary amine mentioned in step (1) includes at least one of dimethylamine, diethylamine, piperidine, or morpholine.

[0020] Furthermore, in step (1), the molar ratio of epichlorohydrin to secondary amine is 1:1-1.2; and / or, in step (2), the molar ratio of intermediate 1 to sodium hydrosulfide is 1:1-1.5.

[0021] Further, the sulfonating agent in step (4) is selected from one or more of sodium 3-chloro-2-hydroxypropanesulfonate, 1,3-propanesulfonate lactone, 2-methyl-1,3-propanesulfonate lactone or 2-ethyl-1,3-propanesulfonate lactone.

[0022] Furthermore, in step (3), the molar ratio of intermediate 2 to short fluorocarbon alkyl iodine is 1:1-1.2.

[0023] Furthermore, in step (4), the molar ratio of perfluoroalkyl sulfide propyl tertiary amine to sulfonating reagent is 1:1-2.

[0024] Furthermore, steps (1) to (4) of the above preparation method are all carried out in an organic solvent, which includes at least one of acetonitrile, acetone, tetrahydrofuran, N,N-dimethylformamide or dimethyl sulfoxide; the reaction in step (4) is carried out in a mixed solvent of organic solvent and water, and the pH of the system is controlled to be 7.0-9.0 during the reaction.

[0025] A short-fluorocarbon alkyl sulfonyl betaine surfactant prepared by the above preparation method has the following general formula structure: Rf-ABC; Wherein, Rf is a C2-C6 straight-chain or branched perfluoroalkyl group; A is a C1-C8 alkylene group; B is -SCH2CH(OH)N(R1)(R2)-; C is -CH2CH(R3)CH2SO3 - .

[0026] Furthermore, in the B group, R1 and R2 together form a C2-C6 carbocycloalkyl group, wherein one or two heteroatoms selected from oxygen atoms and sulfur atoms are inserted, and the heteroatoms may be the same or different.

[0027] A fire extinguishing agent composition comprising the above-mentioned short-fluorocarbon alkyl sulfobetaine surfactant.

[0028] The beneficial effects of this invention are: (1) The synthetic route of this invention avoids the use of highly toxic, flammable, and explosive reagents such as sodium hydride and chlorine throughout the process. It selects conventional chemicals with high safety and easy storage and transportation, such as sodium sulfide and sulfonyl lactone, and the reaction conditions are mild, which greatly reduces the safety risks, equipment requirements and operation difficulty in the production process, and lays a solid foundation for the industrial scale-up of the technology and safe production.

[0029] (2) The short-fluorocarbon alkyl sulfonyl betaine prepared by the method integrates the hydrophobic and heat-resistant properties of the short fluorocarbon chain, the flexibility of the thioether linker arm, and the strong ionicity of the sulfonate group into its molecular structure. This structure endows the product with extremely low surface tension and interfacial tension, while the properties of sulfonyl betaine ensure its chemical stability in a wide pH range, high hardness, and electrolyte solutions, overcoming the shortcomings of traditional carboxyl betaine.

[0030] (3) When this product was applied to aqueous film-forming foam extinguishing agents, the test results showed that its extinguishing agent composition exhibited excellent comprehensive performance and good foaming performance. Compared with the control product, it showed a faster extinguishing speed and a more durable fireproof isolation effect under the same test conditions.

[0031] (4) This invention uses short-chain (C2-C6) perfluoroalkyl raw materials, which is in line with the trend of environmental protection. The synthesis route is reasonably designed, the steps are simple, and the atom economy is high. It avoids the use of expensive or difficult-to-recycle raw materials. The overall process produces less waste, and the production cost and environmental protection cost are effectively controlled, which enhances the market competitiveness of the product. Attached Figure Description

[0032] Figure 1 The image shows the 1H NMR spectrum of the product obtained by the safe preparation method of the short fluorocarbon alkyl sulfobetaine surfactant in Example 4 of this invention.

[0033] Figure 2 The nuclear magnetic resonance fluorine spectrum of the product obtained by the safe preparation method of short fluorocarbon alkyl sulfobetaine surfactant in Example 4 of this invention.

[0034] Figure 3 The liquid chromatogram of the product obtained by the safe preparation method of short fluorocarbon alkyl sulfobetaine surfactant in Example 4 of the present invention.

[0035] Figure 4 The mass spectrum of the product obtained by the safe preparation method of short fluorocarbon alkyl sulfobetaine surfactant in Example 4 of this invention. Detailed Implementation

[0036] The specific implementation method is described below with reference to the accompanying drawings.

[0037] Example 1 This embodiment provides a safe preparation method for a short-fluorocarbon alkyl sulfonyl betaine surfactant. The preparation process is as follows: (1) Add 3.9g epichlorohydrin and 12g acetonitrile to the reactor, vent the reactor, cool it to 0-5℃, and slowly add 1.2 equivalents of dimethylamine aqueous solution. React overnight at the dropping temperature. After washing three times with 20% saline, intermediate 1 solution is obtained.

[0038] (2) After heating the solution of 17.8g intermediate 1 to 30-40℃, 1.2 equivalents of sodium hydrosulfide aqueous solution were slowly added. The reaction was carried out overnight at the dropping temperature. After washing three times with 20% saline, the solution of intermediate 2 was obtained.

[0039] (3) 17.7g of intermediate 2 solution was added to the reactor, the reactor was emptied, the temperature was raised to 20-30℃, and 1 equivalent of perfluorohexyl ethyl iodine was slowly added dropwise. The reaction was carried out overnight at the addition temperature to obtain a perfluoroalkyl sulfide propyl tertiary amine solution.

[0040] (4) A solution containing 20g of perfluorohexyl ethyl sulfide propyl tertiary amine and 6.1g of propanesulfonic acid lactone were added to a reaction flask, heated to 80-90℃ and refluxed for 7 hours. 80mL of acetonitrile was added and stirred at room temperature for 2 hours. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain perfluorohexyl ethyl sulfide propyl propanesulfonic betaine 9#, with a total yield of 53.2%.

[0041] Example 2 This embodiment provides a safe method for preparing short-fluorocarbon alkyl sulfonyl betaine surfactants. The preparation process is as follows: (1) Add 3.9g epichlorohydrin and 12g acetonitrile to the reactor, vent the reactor, cool it to 0-5℃, and slowly add 1.2 equivalents of dimethylamine aqueous solution. React overnight at the dropping temperature. After washing three times with 20% saline, intermediate 1 solution is obtained.

[0042] (2) After heating the solution of 17.8g intermediate 1 to 30-40℃, 1.2 equivalents of sodium hydrosulfide aqueous solution were slowly added. The reaction was carried out overnight at the dropping temperature. After washing three times with 20% saline, the solution of intermediate 2 was obtained.

[0043] (3) 17.7g of intermediate 2 solution was added to the reactor, the reactor was emptied, the temperature was raised to 20-30℃, and 1 equivalent of perfluorobutyl ethyl iodine was slowly added dropwise. The reaction was carried out overnight at the addition temperature to obtain perfluoroalkyl sulfide propyl tertiary amine solution.

[0044] (4) A solution containing 20g of perfluorobutyl ethyl sulfide propyl tertiary amine and 7.4g of propanesulfonic acid lactone were added to a reaction flask, heated to 80-90℃ and refluxed for 7 hours. 80mL of acetonitrile was added and stirred at room temperature for 2 hours. After filtration, the filter cake was dried under reduced pressure to obtain perfluorobutyl ethyl sulfide propyl propanesulfonic betaine 10#, with a total yield of 54.5%.

[0045] Example 3 This embodiment provides a safe method for preparing short-fluorocarbon alkyl sulfonyl betaine surfactants. The preparation process is as follows: (1) Add 3.9g epichlorohydrin and 12g acetonitrile to the reactor, vent the reactor, cool it to 0-5℃, and slowly add 1.2 equivalents of dimethylamine aqueous solution. React overnight at the dropping temperature. After washing three times with 20% saline, intermediate 1 solution is obtained.

[0046] (2) After heating the solution of 17.8g intermediate 1 to 30-40℃, 1.2 equivalents of sodium hydrosulfide aqueous solution were slowly added. The reaction was carried out overnight at the dropping temperature. After washing three times with 20% saline, the solution of intermediate 2 was obtained.

[0047] (3) 17.7g of intermediate 2 solution was added to the reactor, the reactor was emptied, the temperature was raised to 20-30℃, and 1 equivalent of perfluorobutyl ethyl iodine was slowly added dropwise. The reaction was carried out overnight at the addition temperature to obtain perfluoroalkyl sulfide propyl tertiary amine solution.

[0048] (4) A solution containing 20g of perfluorobutyl ethyl sulfide propyl tertiary amine, 12.4g of sodium 3-chloro-2-hydroxypropanesulfonate, and 20ml of deionized water were added to a reaction flask. The mixture was heated to 80-90℃ and refluxed for 24 hours. Sodium hydroxide solution was added during the reaction to maintain the pH of the reaction system at 7-9. After the reaction was completed, the mixture was concentrated under reduced pressure, and water and a small amount of isopropanol were added. The mixture was heated to 80-90℃ and recrystallized for 2 hours. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain perfluorobutyl ethyl sulfide propyl hydroxysulfobetaine 11#, with a total yield of 56.0%.

[0049] Example 4 This embodiment provides a safe method for preparing short-fluorocarbon alkyl sulfonyl betaine surfactants. The preparation process is as follows: (1) Add 3.9g epichlorohydrin and 12g acetonitrile to the reactor, vent the reactor, cool it to 0-5℃, and slowly add 1.2 equivalents of dimethylamine aqueous solution. React overnight at the dropping temperature. After washing three times with 20% saline, intermediate 1 solution is obtained.

[0050] (2) After heating the solution of 17.8g intermediate 1 to 30-40℃, 1.2 equivalents of sodium hydrosulfide aqueous solution were slowly added. The reaction was carried out overnight at the dropping temperature. After washing three times with 20% saline, the solution of intermediate 2 was obtained.

[0051] (3) 17.7g of intermediate 2 solution was added to the reactor, the reactor was emptied, the temperature was raised to 20-30℃, and 1 equivalent of perfluorohexyl ethyl iodine was slowly added dropwise. The reaction was carried out overnight at the addition temperature to obtain a perfluoroalkyl sulfide propyl tertiary amine solution.

[0052] (4) A solution containing 20g of perfluorohexyl ethyl sulfide propyl tertiary amine, 9.8g of sodium 3-chloro-2-hydroxypropanesulfonate, 40mL of isopropanol, and 20mL of deionized water were added to a reaction flask. The mixture was heated to 80-90℃ and refluxed for 24 hours. Sodium hydroxide solution was added during the reaction to maintain the pH of the reaction system at 7-9. After the reaction was completed, the mixture was concentrated under reduced pressure, and water and a small amount of isopropanol were added. The mixture was then heated to 80-90℃ for recrystallization for 2 hours. After filtration, the filter cake was dried under reduced pressure to obtain perfluorohexyl ethyl sulfide propyl hydroxysulfobetaine 4#, with a total yield of 56.8%.

[0053] The prepared product #4 was analyzed by NMR and LCMS as shown in the attached figure. Figure 1 , 2 As shown in Figures 3 and 4, the ¹H NMR (400MHz, CD3OD) values ​​are: δ4.32–4.37 (m, ¹H), 3.57–3.69 (m, 2H), δ3.42–3.51 (m, 2H), δ3.21 (s, 6H), δ2.81–2.97 (m, 4H), δ2.67–2.78 (m, 2H), δ2.46–2.60 (m, 2H), δ2.16–2.32 (m, 2H). 19F NMR (376 MHz, CD3OD) δ-82.44, -115.28, -122.95, -123.94, -124.42, -127.38.

[0054] LCMS(Pos, Acid) shows: [M+H]+ = 604.2, while C 16 H 22 F 13 The m / z of NO4S2 is 603.2, and the obtained value is the target molecular weight.

[0055] Experimental Example 1 This experimental example provides tests on the surface tension and interfacial tension of the short fluorocarbon alkyl sulfobetaine surfactant prepared in Example 4 above.

[0056] (1) Experimental methods Preparation method for 0.10% solution: Weigh 1.00g of short-fluoroalkyl sulfonyl betaine and dilute with 99.00g of deionized water to obtain 1.00% short-fluoroalkyl sulfonyl betaine. Take 10.00g of 1.00% short-fluoroalkyl sulfonyl betaine and dilute with 90.00g of deionized water to obtain 0.10% short-fluoroalkyl sulfonyl betaine.

[0057] Preparation method for 0.05% solution: Weigh 1.00g of short-fluoroalkyl sulfonyl betaine and dilute with 99.00g of deionized water to obtain 1.00% short-fluoroalkyl sulfonyl betaine. Take 5.00g of 1.00% short-fluoroalkyl sulfonyl betaine and dilute with 95.00g of deionized water to obtain 0.05% short-fluoroalkyl sulfonyl betaine.

[0058] Preparation method for 0.01% solution: Weigh 1.00g of short-fluoroalkyl sulfonyl betaine and dilute with 99.00g of deionized water to obtain 1.00% short-fluoroalkyl sulfonyl betaine. Take 1.0g of 1.00% short-fluoroalkyl sulfonyl betaine and dilute with 99.00g of deionized water to obtain 0.01% short-fluoroalkyl sulfonyl betaine.

[0059] Surface tension was tested according to the ring-pulling method in GB / T 22237-2008, determining the surface tension of short-fluorocarbon alkyl sulfobetaine surfactants.

[0060] (2) Sample setup Based on the short fluorocarbon sulfobetaine structure Rf-ABC, samples 1#-8# were synthesized by following the same preparation method as in Example 4, except that the structures of Ff, A, B and C were changed during the preparation process. Their structures are shown in Table 1 below.

[0061] Table 1. Sample Structure Design Table

[0062] The structures of Ff, A, B and C of the short fluorocarbon sulfobetaine used in the preparation of samples 9#-11# are the same as those of sample 4#.

[0063] Additionally, a control standard 1 was prepared, consisting of 27% perfluorohexyl ethyl sulfonamide propyl betaine, 30% ethylene glycol, and the remainder being water.

[0064] Reference standard 2: It consists of 27% perfluorooctyl ethyl sulfonamide propyl hydroxy sulfonate betaine, 30% ethylene glycol, and the remainder is water.

[0065] Reference standard 3: It consists of 27% perfluorobutyl ethyl sulfonamide propyl hydroxysulfonate betaine, 30% ethylene glycol, and the remainder is water.

[0066] Reference standard 4: It consists of 27% perfluorohexyl ethyl ether propyl betaine, 30% ethylene glycol, and the remainder is water.

[0067] Following the experimental method described above, samples 1#-8# were prepared as sample solutions 1#-8#, each consisting of 27% short-chain alkyl sulfoethyl betaine, 30% ethylene glycol, and the remainder water. These solutions were then compared with reference standards 1-4. Samples 1#-8# and reference standards 1-4 were diluted 2000 times with pure water to prepare solutions of the same concentration, and the surface tension and interfacial tension of each solution were measured.

[0068] (3) Experimental results The results are shown in Table 2 below.

[0069] Table 2. Surface tension and interfacial tension test results

[0070] The test results above show that, at the same concentration, the longer the fluorocarbon chain in the Rf group, the lower the surface tension and interfacial tension of the sample. Increasing the number of carbon chains in parts A and B has a certain effect on reducing surface tension, but as the number of carbon atoms increases, the interfacial tension also increases. In part C, the increased polarity of the functional groups leads to increased surface tension and interfacial tension.

[0071] Experimental Example 2 This experimental example provides a fire extinguishing experiment on the short fluorocarbon alkyl sulfobetaine surfactant prepared in Example 4 above.

[0072] (1) Experimental methods Sample solutions 4#, 9#, 10# and 11# from Experimental Example 1 were respectively prepared with reference standards 1, 2, 3 and 4 to form corresponding fire extinguishing agent compositions.

[0073] The fire extinguishing composition, by weight, consists of: 0.6% fluorocarbon surfactant solution (test sample), 3% diethylene glycol butyl ether, 8% hydrocarbon foaming agent, and the remainder is water. According to the requirements of foam fire extinguishing agents (GB / T15308-2025), the prepared fire extinguishing agent composition was tested for foaming performance, fire extinguishing performance, and fire resistance.

[0074] (2) Experimental results The results are shown in Table 3 below.

[0075] Table 3. Results of foaming ratio, fire extinguishing test and burning resistance test

[0076] It can be seen that the foaming ratio is generally between 7.7 and 8.1 times, with sample #4 having a slightly higher foaming ratio of 8.04 times.

[0077] Fire extinguishing experiments showed that #4 was extinguished within 1 minute and 15 seconds, while the extinguishing time for the other samples exceeded 1 minute and 20 seconds. This invention demonstrates excellent fire extinguishing efficiency.

[0078] The burn resistance test revealed that controls 2, 11#, and 4# had longer burn resistance times, all exceeding 17 minutes, specifically 17 minutes 25 seconds and 17 minutes 12 seconds respectively. Sample 4# achieved the best burn resistance time at 17 minutes 38 seconds. Among the remaining samples, control 3 only lasted 12 minutes 34 seconds, while controls 1, 4, 9#, and 10# had burn resistance times between 16 and 17 minutes.

Claims

1. A safe preparation method for a short-fluorocarbon alkyl sulfonyl betaine surfactant, characterized in that, Includes the following steps: (1) In solvent system I, epichlorohydrin reacts with a secondary amine to obtain intermediate 1; (2) In solvent system II, intermediate 1 reacts with sodium hydrosulfide or its hydrate to obtain intermediate 2; (3) Intermediate 2 reacts with a short-fluorocarbon alkyl iodine to give a perfluoroalkyl sulfide propyl tertiary amine; the structure of the short-fluorocarbon alkyl iodine is C n F 2n+1 C m H 2m I, where n is an integer from 2 to 6, and m is an integer from 1 to 8; (4) Perfluoroalkyl sulfide propyl tertiary amine is sulfonated to obtain short-fluorocarbon alkyl sulfobetaine surfactant; R1 and R2 are each independently a C1-C4 alkyl group, or R1 and R2 together form a C2-C6 carbocycloalkyl group or a carbocycloalkyl group containing oxygen / sulfur heteroatoms. Both ends of the carbocycloalkyl group are connected to the N atom to form a cyclic secondary amine structure, and R3 is H, OH or a C1-C3 alkyl group.

2. The safe preparation method of the short-fluorocarbon alkyl sulfonyl betaine surfactant according to claim 1, characterized in that, The secondary amine mentioned in step (1) includes at least one of dimethylamine, diethylamine, piperidine, or morpholine.

3. The safe preparation method of the short-fluorocarbon alkyl sulfonyl betaine surfactant according to claim 1, characterized in that, In step (1), the molar ratio of epichlorohydrin to secondary amine is 1:1-1.2; and / or, in step (2), the molar ratio of intermediate 1 to sodium hydrosulfide is 1:1-1.

5.

4. The safe preparation method of the short-fluorocarbon alkyl sulfonyl betaine surfactant according to claim 1, characterized in that, The sulfonating agent in step (4) is selected from one or more of sodium 3-chloro-2-hydroxypropanesulfonate, 1,3-propanesulfonate lactone, 2-methyl-1,3-propanesulfonate lactone or 2-ethyl-1,3-propanesulfonate lactone.

5. The safe preparation method of the short-fluorocarbon alkyl sulfonyl betaine surfactant according to claim 1, characterized in that, In step (3), the molar ratio of intermediate 2 to short fluorocarbon alkyl iodine is 1:1-1.

2.

6. The safe preparation method of the short-fluorocarbon alkyl sulfonyl betaine surfactant according to claim 1, characterized in that, In step (4), the molar ratio of perfluoroalkyl sulfide propyl tertiary amine to sulfonating reagent is 1:1-2.

7. The safe preparation method of the short-fluorocarbon alkyl sulfonyl betaine surfactant according to claim 1, characterized in that, Steps (1) to (4) of the above preparation method are all carried out in an organic solvent, which includes at least one of acetonitrile, acetone, tetrahydrofuran, N,N-dimethylformamide or dimethyl sulfoxide; the reaction in step (4) is carried out in a mixed solvent of organic solvent and water, and the pH of the system is controlled to be 7.0-9.0 during the reaction.

8. A short-fluorocarbon alkyl sulfonyl betaine surfactant prepared by the safe preparation method according to any one of claims 1-7, characterized in that, It has the following general formula structure: Rf-ABC; Wherein, Rf is a C2-C6 straight-chain or branched perfluoroalkyl group; A is a C1-C8 alkylene group; B is -SCH2CH(OH)N(R1)(R2)-; C is -CH2CH(R3)CH2SO3 - .

9. The short-fluorocarbon alkyl sulfonyl betaine surfactant according to claim 8, characterized in that, In the B group, R1 and R2 together form a C2-C6 carbocycloalkyl group, wherein one or two heteroatoms selected from oxygen atoms and sulfur atoms are inserted, and the heteroatoms may be the same or different.

10. A fire extinguishing agent composition, characterized in that, It contains the short-fluorocarbon alkyl sulfobetaine surfactant as described in claim 8 or 9.

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