Highly stable environment-friendly foam extinguishing agent and preparation method thereof

Abstract

This invention discloses a highly stable and environmentally friendly foam fire extinguishing agent and its preparation method. The tetrasiloxane surfactant used includes one or two of the structural formulas [formulas omitted]. The highly stable and environmentally friendly foam fire extinguishing agent prepared using the tetrasiloxane surfactant of this invention exhibits excellent stability, oil resistance, film-forming properties, and fire extinguishing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foam extinguishing agent, and particularly relates to a high-stability environment-friendly foam extinguishing agent and a preparation method thereof. BACKGROUND

[0002] In the field of transformer oil fire extinguishing, traditional water film-forming foam extinguishing agent relies on perfluorooctane sulfonate (PFOS) and other fluorocarbon surfactants to realize oil surface spreading, thereby achieving efficient fire extinguishing. However, such substances have biological accumulation and environmental persistent pollution risks, and have been completely banned by international conventions.

[0003] Although the existing fluorine-free alternative solutions (such as fluorine-free foam extinguishing agents taking a trisiloxane organosilicon surfactant / hydrocarbon surfactant compound system as the core) have improved environmental performance, the hydrocarbon surfactant has "lipophilicity", and the trisiloxane organosilicon surfactant has "oleophobicity" deficiency, resulting in insufficient foam layer structure stability and insufficient high-temperature hot oil vapor sealing capacity. Fuel vapor can easily penetrate the foam layer and continue to burn, accelerating the rupture of the foam layer. Therefore, the existing fluorine-free foam extinguishing agent is difficult to completely and effectively extinguish flammable liquid fires. SUMMARY

[0004] The technical problem to be solved by the present application is how to improve the performance of fluorine-free foam extinguishing agent.

[0005] The present application solves the above technical problems by the following technical means:

[0006] A surfactant, the surfactant comprises a mixture of one or two of the following structure formulae:

[0007]

[0008] Bis-N-tris (trimethylsiloxy) silpropoxyethyl-N, N-dimethyl ethyldiammonium bromide

[0009]

[0010] Tris (trimethylsiloxy) siloxy octaethylenyl butyric acid sodium.

[0011] Preferably, when the compound system is used, it further comprises a trisiloxane surfactant, and the mass ratio of the trisiloxane surfactant, the tetrasiloxane surfactant and the trisiloxane surfactant is 15-25:10-15.

[0012] Preferably, the surfactant comprises a mixture of tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide and tetrasiloxane surfactant sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate, wherein the mass ratio of tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide to tetrasiloxane surfactant sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate is 5-15:5-10.

[0013] Preferably, the trisiloxane surfactant is CoatOsil-77 (purchased from Shanghai Sangjing Chemical Co., Ltd.) or DOWSIL. TM One or more of the following: 502W (purchased from Guangzhou Siteyuan Chemical Co., Ltd.), M-9120 (purchased from Guangzhou Chuying New Material Technology Co., Ltd.), UF-1328 (purchased from Ausjia Materials Technology (Shanghai) Co., Ltd.), and UF-5811 (purchased from Ausjia Materials Technology (Shanghai) Co., Ltd.).

[0014] The present invention also provides a method for preparing the aforementioned surfactant, comprising the following steps:

[0015] S1. Under an anhydrous environment, in an organic solvent, using allyl alcohol and 1,2-dibromoethane as raw materials, a reaction is carried out in the presence of anhydrous potassium carbonate to obtain an olefinic ether derivative.

[0016] S2. Under anhydrous conditions and in an organic solvent, using tris(trimethylsiloxy)silane (Me3SiO)3SiH as a raw material, an alkenyl ether derivative is used and reacted with (Me3SiO)3SiH in the presence of a platinum catalyst to obtain a siloxane compound.

[0017] S3. In an anhydrous environment and in an organic solvent, using siloxane compounds as raw materials, dimethyl ethylenediamine is used to react and obtain the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide.

[0018] Preferably, the synthetic route for the alkenyl ether derivative in S1 is as follows:

[0019]

[0020] Preferably, the organic solvent in S1 is N,N-dimethylformamide; the organic solvent in S2 is one or a mixture of two of anhydrous tetrahydrofuran and anhydrous dichloromethane; the platinum catalyst in S2 is a Karstedt catalyst (CAS: 81032-58-8); and the organic solvent in S3 is one or a mixture of two of anhydrous acetonitrile and anhydrous dichloromethane.

[0021] Preferably, in the reaction process S1, the reaction temperature is 60°C and the reaction time is 12 hours; in the reaction process S2, the reaction temperature is 40-60°C and the reaction time is 6-12 hours; in the reaction process S3, the reaction temperature is room temperature and the reaction time is 6-10 hours.

[0022] Preferably, in S1, the mass ratio of allyl alcohol to 1,2-dibromoethane is 5:18; in S2, the mass ratio of tris(trimethylsiloxy)silane to alkenyl ether derivative is 1:1; the mass ratio of alkenyl ether derivative to platinum catalyst is 18:0.5; and in S3, the mass ratio of siloxane compound to dimethylethylenediamine is 20:4.

[0023] The present invention also provides a method for preparing the aforementioned surfactant, comprising the following steps:

[0024] S1. Under an anhydrous environment, in an organic solvent, using tris(trimethylsiloxy)silane as a raw material, ethylene oxide is used, and the reaction is carried out under the action of an alkaline reagent to obtain a sodium alkoxide intermediate.

[0025] S2. In an anhydrous environment, in an organic solvent, using sodium alkoxide intermediate as raw material, 5-bromopentonitrile is used and the reaction is carried out in the presence of a proton buffer to obtain nitrile intermediate;

[0026] S3. Using nitrile intermediates as raw materials, a strong acid and a strong base are used to react the tetrasiloxane surfactant tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate sodium salt.

[0027] Preferably, in S1, the organic solvent is one or a mixture of two of anhydrous toluene or anhydrous dichloromethane, and the alkaline reagent is triphenylmethyl sodium; in S2, the organic solvent is one or a mixture of two of anhydrous dichloromethane and anhydrous tetrahydrofuran, and the proton buffer is one or a mixture of two of sodium carbonate or triethylamine; in S3, the strong acid is a 10% (w / w) dilute sulfuric acid solution, and the strong base is a 30% (w / w) sodium hydroxide solution.

[0028] Preferably, in S1, the mass ratio of tris(trimethylsiloxy)silane to ethylene oxide is 20:28; in S2, the mass ratio of sodium alkoxide intermediate to 5-bromopentonitrile is 20:8; and in S3, the mass ratio of nitrile intermediate, strong acid, and strong base is 20:8:9.

[0029] Preferably, in S1, the reaction temperature is 70°C and the reaction time is 15 hours; in S2, the reaction temperature is room temperature and the reaction time is 10 hours.

[0030] Preferably, in reaction S1, tris(trimethylsiloxy)silane is first dissolved in an organic solvent, then an alkaline reagent is added, and the reaction is carried out for 2 hours; then ethylene oxide is added, and the reaction is carried out at 70-80°C for 15 hours until the reaction is complete; in reaction S2, the sodium alkoxide intermediate is first dissolved in an organic solvent, then 5-bromopentanilonitrile is slowly added dropwise under stirring in an ice bath at 0°C, while a proton buffer is added simultaneously. After the addition is completed, the reaction is carried out at room temperature for 8-12 hours until the reaction is complete; in reaction S3, the nitrile intermediate is first added to a strong acid and reacted at 120°C for 24-36 hours; then a strong base is added, and the reaction is carried out at room temperature for 2-4 hours until the reaction is complete.

[0031] The present invention also proposes the application of the surfactant in fire extinguishing agents.

[0032] The present invention also proposes a highly stable and environmentally friendly foam fire extinguishing agent containing the aforementioned surfactant.

[0033] Preferably, the surfactant accounts for 15%-40% of the mass of the highly stable and environmentally friendly foam fire extinguishing agent.

[0034] Preferably, the raw materials of the highly stable environmentally friendly foam fire extinguishing agent also include co-solvents, organic solvents, thickeners, and preservatives.

[0035] Preferably, the high-stability environmentally friendly foam fire extinguishing agent comprises, by mass percentage, 15%-40% surfactant, 1%-1.5% co-solvent, 0.8%-1.2% organic solvent, 0.5%-1% thickener, 0.5%-0.8% preservative, with the balance being water.

[0036] Preferably, the co-solvent is urea; the organic solvent is isobutanol; the thickener is one or a mixture of two of hydroxyethyl cellulose and xanthan gum; and the preservative is benzoic acid.

[0037] The present invention also proposes a method for preparing the highly stable environmentally friendly foam fire extinguishing agent, comprising mixing surfactants with other raw materials uniformly to obtain the highly stable environmentally friendly foam fire extinguishing agent.

[0038] Preferably, the preparation method of the highly stable environmentally friendly foam fire extinguishing agent includes the following steps: taking a portion of water, adding a surfactant, and stirring to obtain a surfactant compound solution; mixing a cosolvent and a thickener evenly, adding them to the surfactant compound solution, and stirring; adding an organic solvent and a preservative, adding water, and stirring to obtain the foam fire extinguishing agent.

[0039] Preferably, the cosolvent and thickener are mixed evenly, and then added to the surfactant compound solution under heating and stirring conditions, followed by stirring.

[0040] Preferably, the cosolvent and thickener are mixed evenly and then added to the surfactant compound solution under stirring conditions of 50-60 degrees Celsius and 2000 rpm, and stirred for 90 min.

[0041] Preferably, after adding water, the mixture is cooled to room temperature and stirred at 1500 rpm for 60 minutes.

[0042] The present invention also proposes a fire extinguishing device containing the aforementioned highly stable and environmentally friendly foam fire extinguishing agent.

[0043] The advantages of this invention are:

[0044] (1) Based on the self-synthesized tetrasiloxane surfactant, this invention develops a highly stable and environmentally friendly foam extinguishing agent formula to address the technical bottleneck of poor fire extinguishing performance of existing fluorine-free foam extinguishing agents. This product fully complies with the requirements of the national standard GB15308-2006 "Foam Extinguishing Agents" and has good foam performance and fire extinguishing performance.

[0045] (2) For transformer oil fires, the high-stability environmentally friendly foam extinguishing agent of this invention has excellent foaming performance, foam stability, fire extinguishing performance and film-forming performance. Its foaming ratio is 7-8 times; the 25% liquid separation time is 11.2-15 min; the fire extinguishing time is 54 s-98 s; the fire resistance time is 10 min 55 s-14 min 30 s; and the film-forming speed is 1.3-1.9 cm. 2 / s. Under the same conditions, compared with commercial 3% aqueous film-forming foam fire extinguishing agent, the foaming ratio is increased by 19.05%-36.05%, the liquid separation time of 25% is extended by 212.56%-318.60%, the extinguishing time is shortened by 50.00%-72.45%, the anti-burning time is extended by 17.59%-56.19%, and the film-forming speed is increased by 8.33%-58.33%.

[0046] (3) This invention has developed a new process for the efficient synthesis of tetrasiloxane surfactants with a simple route and mild conditions.

[0047] (4) The present invention establishes a simple process, mild conditions and good repeatability for preparing foam extinguishing agent stock solution. The prepared foam extinguishing agent stock solution is uniform and stable after standing for 180 days, without stratification or changes in properties. Attached Figure Description

[0048] Figure 1 These are actual images of the surfactant compound system solutions in Examples 1-4 of this invention.

[0049] Figure 2 The graphs show the test data of the film-forming performance of the surfactant compound system solutions in Examples 1-4 and Comparative Examples 1-2 of this invention.

[0050] Figure 3 The graph shows the oil resistance test data of the solutions of the surfactant complex systems of Examples 1-4, Comparative Examples 1-2 and QE-80 / LS-408L and QE-80 / BS-12 of the present invention.

[0051] Figure 4 The performance test results of a highly stable environmentally friendly foam fire extinguishing agent under different concentrations of sodium tri(trimethylsiloxy)silyloctyl polyoxyethyl butyrate surfactant (THS).

[0052] Figure 5 The results of performance tests on highly stable environmentally friendly foam fire extinguishing agents at different concentrations of tetrasiloxane surfactants bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide.

[0053] Figure 6 The test results of high-stability environmentally friendly foam fire extinguishing agent under different concentrations of trisiloxane surfactants;

[0054] Figure 7 The results of performance tests on highly stable environmentally friendly foam fire extinguishing agents under different thickener concentrations;

[0055] Figure 8 This is a static image of the environmentally friendly foam fire extinguishing agent stock solution prepared in Example 5 of the present invention.

[0056] Figure 9 This is a static image of the foam extinguishing agent stock solution prepared in Comparative Example 9 of this invention.

[0057] Figure 10 These are experimental images showing the film-forming phenomena of the environmentally friendly foam fire extinguishing agents and 3% AFFF corresponding to Examples 5-10 and Comparative Examples 4, 6, and 8 of the present invention.

[0058] Figure 11 These are experimental phenomena of the high-stability environmentally friendly foam fire extinguishing agents in Examples 5-10 of this invention.

[0059] Figure 12 These are experimental images showing the extinguishing phenomena of foam fire extinguishing agents and 3% AFFF corresponding to Comparative Examples 3-8 of this invention.

[0060] Figure 13 The graphs show the oil resistance test data of the high-stability environmentally friendly foam fire extinguishing agent and 3% AFFF corresponding to Examples 5-10 and Comparative Examples 3-8 of this invention.

[0061] Figure 14 The graphs show the film-forming performance test data of the high-stability environmentally friendly foam fire extinguishing agent and 3% AFFF corresponding to Examples 5-10 and Comparative Examples 4, 6, and 8 of this invention. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0064] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0065] Example 1

[0066] The environmentally friendly foam fire extinguishing agent surfactant compound system of this embodiment is composed of tetrasiloxane surfactant and trisiloxane surfactant in a mass ratio of 25:15.

[0067] The tetrasiloxane surfactant is bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediamium bromide, and its structural formula and synthetic route are as follows:

[0068]

[0069]

[0070] The specific synthesis path is as follows:

[0071] Step 1: Synthesis of tris(trimethylsiloxy)silane. Under an anhydrous and nitrogen-protected environment, at 2°C, 15g of trichlorosilane (HSiCl3) was dissolved in 60g of anhydrous n-hexane, followed by the addition of 30g of pyridine, and then 30g of trimethylsilanol was slowly added with stirring. After the addition was complete, the mixture was stirred for another 2 hours. Subsequently, the system was heated to 60°C and stirred for another 0.5 hours to ensure complete reaction. Byproducts were removed by vacuum distillation to obtain tris(trimethylsiloxy)silane (Me3SiO)3SiH.

[0072]

[0073] Step 2: Introducing the carbon chain. Under an anhydrous environment, 18g of the alkenyl ether derivative... The solution was dissolved in 40 g of anhydrous tetrahydrofuran, and 18 g of (Me3SiO)3SiH was slowly added under stirring, followed by 0.5 g of Karstedt catalyst. The mixture was stirred at 45 °C for 6 hours until the silane-hydrogen bond reaction was complete, yielding the siloxane compound (Me3SiO)3Si(CH2)3O(CH2)2Br. After the reaction was complete, the solvent was removed by distillation, and the catalyst and byproducts were washed away with water.

[0074]

[0075] Step 3: Reaction with dimethylethylenediamine. Under anhydrous conditions and at 25°C, 20g of the siloxane compound (Me3SiO)3Si(CH2)3O(CH2)2Br was dissolved in 50g of anhydrous acetonitrile. Then, 4g of dimethylethylenediamine was slowly added, and the mixture was stirred for 8 hours until the reaction was complete. After the reaction, unreacted amine was removed by washing with water and dried with anhydrous sodium sulfate. The pure product was then obtained by evaporating the solvent. The NMR data are as follows:

[0076] 13 C NMR (100 MHz, CDCl3) δ 70.9, 68.4, 63.6, 61.4, 51.1, 25.5, 10.6,1.7.

[0077] 1 H NMR (400 MHz, CDCl3) δ 3.70 (t, J = 7.0 Hz, 4H,), 3.47 (t, J = 7.8Hz, 4H), 3.36 (t, J = 7.0 Hz, 4H), 2.89 (s, 12H), 3.31 (t, J = 7.3 Hz, 4H), 2.07 (tt, J = 7.5, 7.3 Hz, 4H), 1.14 (t, J = 7.5 Hz, 4H), 0.07 (54H, s).

[0078] The process is as follows:

[0079]

[0080] The trisiloxane surfactant is UF-5811.

[0081] The synthetic routes for alkenyl ether derivatives are as follows:

[0082]

[0083] The specific synthetic route is as follows: Under nitrogen protection and at 25°C, 5g of allyl alcohol and 18g of 1,2-dibromoethane were dissolved in 100mL of N,N-dimethylformamide (DMF). Then, 14g of anhydrous potassium carbonate (K₂CO₃) was slowly added in batches. The mixture was then stirred at 60°C for 12 hours to obtain the target product.

[0084] Example 2

[0085] The environmentally friendly foam fire extinguishing agent surfactant compound system of this embodiment is composed of tetrasiloxane surfactant and trisiloxane surfactant in a mass ratio of 20:15.

[0086] The tetrasiloxane surfactant is sodium tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate, and its structural formula and synthetic route are as follows:

[0087]

[0088]

[0089] The specific synthesis path is as follows:

[0090] Step 1: Synthesis of tris(trimethylsiloxy)silane. The synthetic route for this step is the same as the first step of the synthetic route for the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide in Example 1.

[0091] Step 2: Reaction with ethylene oxide. At 25°C, 20g of tris(trimethylsiloxy)silane was dissolved in 80g of anhydrous dichloromethane, and 0.05g of triphenylmethyl sodium was slowly added. After stirring for 2 hours, 28g of ethylene oxide was added, and the mixture was heated to 70°C to carry out the epoxide ring-opening reaction. The mixture was stirred for 15 hours to allow Si-H to undergo an addition reaction with ethylene oxide, generating a sodium alkoxide intermediate.

[0092]

[0093] Step 3: Nucleophilic substitution reaction. 20g of the sodium alkoxide intermediate was dissolved in 80g of anhydrous dichloromethane, and 8g of 5-bromopentanilonitrile was slowly added dropwise with stirring in an ice bath at 0 °C, while simultaneously adding 5g of sodium carbonate (Na₂CO₃) as a proton buffer. The reaction was stirred at room temperature for 10 hours to form a nitrile intermediate.

[0094]

[0095] Step 4: Sodium carboxylate salting reaction. 20g of the nitrile intermediate was dissolved in 80g of a 10% (w / w) dilute sulfuric acid solution and reacted at 120℃ for 24 hours. After the reaction was complete, the temperature was cooled to 25℃, and then 30g of a 30% (w / w) sodium hydroxide solution was slowly added dropwise while stirring for 3 hours until the reaction was complete, yielding the final target product, sodium tris(trimethylsiloxy)silyloctyl polyoxyethyl butyrate. Its NMR data are as follows:

[0096] 13 C NMR (100 MHz, CDCl3) δ 178.5, 71.0, 70.7, 70.2, 66.2, 38.6, 29.1,25.0, 15.8, 1.7.

[0097] 1 H NMR (400 MHz, CDCl3) δ 3.58-3.71 (m, 28H), 3.52 (t, J = 6.5 Hz, 2H), 3.37 (t, J = 7.2 Hz, 2H), 2.01 (t, J = 7.6 Hz, 2H), 1.77 (tt, J = 7.4, 7.2 Hz, 2H), 1.48 (tt, J = 7.6, 7.4 Hz, 2H), 1.43 (t, J = 6.5 Hz, 2H), 0.06 (s, 27H).

[0098] The process is as follows:

[0099]

[0100] The trisiloxane surfactant is CoatOsil-77.

[0101] Example 3

[0102] The environmentally friendly foam fire extinguishing agent surfactant compound system of this embodiment is composed of tetrasiloxane surfactants bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide and sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate. The synthesis routes of the two tetrasiloxane surfactants are the same as those described in Examples 1 and 2; and the mass ratio of bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide and sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate is 8:7.

[0103] Example 4

[0104] The environmentally friendly foam fire extinguishing agent surfactant compound system of this embodiment is composed of tetrasiloxane surfactant and trisiloxane surfactant in a mass ratio of 18:10.

[0105] The tetrasiloxane surfactant is composed of bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide and sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate in a mass ratio of 10:8. The synthesis routes of the two tetrasiloxane surfactants are the same as those described in Examples 1 and 2.

[0106] The trisiloxane surfactant is UF-5811.

[0107] Comparative Example 1

[0108] Same as Example 1, except that the mass ratio of tetrasiloxane surfactant to trisiloxane surfactant is changed to 1:7.

[0109] Comparative Example 2

[0110] Same as Example 2, except that the mass ratio of tetrasiloxane surfactant to trisiloxane surfactant is changed to 1:15.

[0111] The appearance of the surfactant complex solutions prepared in Examples 1-4 is as follows: Figure 1 As shown, the surfactant complex systems obtained in Examples 1-4 can all exist uniformly and stably in water, exhibiting good dispersibility. The performance of different surfactant complex systems was tested. The specific test method was as follows: The film-forming speed test method for the surfactant complex system solution was as follows: ① The apparatus used included a micro-injection pump, an oil pan (15cm in diameter), a high-speed camera, and transformer oil; ② 50mL of transformer oil was placed in the oil pan, and the needle of the micro-injection pump was positioned 2cm directly above the center of the oil pan; ③ At 25℃, surfactant drops were placed on the surface of the transformer oil at a rate of 12μL / drop using the micro-injection pump. The camera recorded the droplet spreading process, and the video data was processed by frame extraction to obtain the maximum spreading area and the time to reach the maximum area. The film-forming speed was calculated by dividing the maximum spreading area by the time to reach the maximum area. The method for testing the oil resistance of the surfactant compound system foam is as follows: First, 30 mL of transformer oil is placed in a 100 mL graduated cylinder; then, foam is generated using the double-syringe method, and 60 mL of foam is placed above the transformer oil. The time for the foam to separate to 25% is recorded using a camera, and this data is used to evaluate the oil resistance. Figures 2-3 As shown:

[0112] Table 1 Performance test results of surfactant compound systems

[0113]

[0114] Among them, the trisiloxane surfactant QE-80 was purchased from Guangzhou Zongyu Chemical Technology Co., Ltd.; the trisiloxane surfactant LS-408L was purchased from Jinan Lvsai Chemical Co., Ltd.; and the hydrocarbon surfactant BS-12 was purchased from Shandong Yousuo Chemical Technology Co., Ltd.

[0115] From Table 1 and Figures 2-3 It can be seen that the surfactant compound systems of Examples 1-4 of the present invention have faster film-forming speeds and longer oil resistance times compared to Comparative Examples 1-2, the trisiloxane / trisiloxane surfactant compound system (QE-80 / LS-408L, mass ratio 8:7), and the trisiloxane / hydrocarbon surfactant compound system (QE-80 / BS-12, mass ratio 8:7). Therefore, the present invention provides a surfactant compound system with excellent film-forming performance and good oil resistance. Experimental results show that the film-forming speed of this surfactant compound system is 1.4-1.8 cm⁻¹. 2 / s, oil resistance is 7-9min.

[0116] Application examples:

[0117] The formulation of a highly stable environmentally friendly foam fire extinguishing agent based on the above surfactant compound system is as follows: by mass percentage, 15%-40% environmentally friendly foam fire extinguishing agent surfactant compound system, 1%-1.5% co-solvent, 0.8%-1.2% organic solvent, 0.5%-1% thickener, 0.5%-0.8% preservative, and the balance is water.

[0118] According to the standard GB 15308-2006 "Foam Extinguishing Agents", the effects of changes in the concentration of single tetrasiloxane surfactants, trisiloxane surfactants and thickeners on the diffusion coefficient, expansion ratio, 25% separation time, extinguishing time and anti-burning time of high-stability environmentally friendly foam extinguishing agent formulations were tested.

[0119] The foam extinguishing agent formulation with fixed mass concentrations of all substances except the tetrasiloxane surfactant sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate is as follows: by mass percentage, 1%-30% sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate, 15% trisiloxane surfactant UF-5811, 1.5% co-solvent urea, 1.2% organic solvent isobutanol, 0.7% thickener xanthan gum, 0.8% preservative benzoic acid, and the balance being water. Based on this formulation, the performance of a highly stable and environmentally friendly foam extinguishing agent at different concentrations of sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate was tested, such as... Figure 4As shown in the diagram, when the concentration of sodium tri(trimethylsiloxy)silyloctyl polyoxyethylbutyrate is below 7%, the foam extinguishing agent exhibits good foaming ratio, but its 25% exudation time and anti-burning time are relatively short, its diffusion coefficient is small, and its extinguishing time is long. When the concentration of sodium tri(trimethylsiloxy)silyloctyl polyoxyethylbutyrate is above 20%, the foam extinguishing agent exhibits good foaming ratio and a large diffusion coefficient, but its 25% exudation time and anti-burning time are relatively short, and its extinguishing time is long. When the concentration of sodium tri(trimethylsiloxy)silyloctyl polyoxyethylbutyrate is between 7% and 20%, the overall performance of the foam extinguishing agent is optimal. Therefore, the optimal concentration range for sodium tri(trimethylsiloxy)silyloctyl polyoxyethylbutyrate is 7%-20%.

[0120] The foam extinguishing agent formulation, with a fixed mass concentration of all substances except the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)siloxyethyl-N,N-dimethylethylenediammonium bromide, is as follows (by mass percentage): 2%-30% bis-N-tris(trimethylsiloxy)siloxyethyl-N,N-dimethylethylenediammonium bromide, 15% trisiloxane surfactant UF-5811, 1.5% urea, 1.2% isobutanol, 0.7% xanthan gum, 0.8% benzoic acid, and the balance being water. Based on this formulation, the performance of a highly stable and environmentally friendly foam extinguishing agent at different concentrations of bis-N-tris(trimethylsiloxy)siloxyethyl-N,N-dimethylethylenediammonium bromide was tested. Figure 5 As shown in the diagram, when the concentration of bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide is below 8%, the foam extinguishing agent has a high foaming ratio, but a low diffusion coefficient, a short 25% exudation time, a short anti-burning time, and a long extinguishing time. When the concentration of bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide is greater than 25%, the foam extinguishing agent has a high foaming ratio and a high diffusion coefficient, but a short 25% exudation time, a short anti-burning time, and a long extinguishing time. When the concentration of bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide is between 8% and 25%, the foam extinguishing agent exhibits the best overall performance. Therefore, the optimal concentration range for bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide is 8%-25%.

[0121] The foam extinguishing agent formulation with fixed mass concentrations of all substances except the trisiloxane surfactant (UF-5811) is as follows: by mass percentage, 7% sodium tris(trimethylsiloxy)silyloctyl polyoxyethyl butyrate, 8% bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediamine bromide, 3%-20% trisiloxane surfactant UF-5811, 1.5% urea, 1.2% isobutanol, 0.7% xanthan gum, 0.8% benzoic acid, and the balance being water. Based on this formulation, the performance of a highly stable and environmentally friendly foam extinguishing agent at different concentrations of trisiloxane surfactant was tested, such as... Figure 6 As shown in the diagram, when the concentration of trisiloxane surfactant is below 10%, the foam extinguishing agent exhibits good expansion ratio, but its diffusion coefficient is relatively low, the 25% exudation time and anti-burning time are short, and the extinguishing time is long. When the concentration of trisiloxane surfactant is above 15%, the foam extinguishing agent has a high expansion ratio and diffusion coefficient, but its 25% exudation time and anti-burning time are short, and the extinguishing time is long. When the concentration of trisiloxane surfactant is between 10% and 15%, the overall performance of the foam extinguishing agent is optimal. Therefore, the optimal concentration range for trisiloxane surfactant is 10%-15%.

[0122] The foam extinguishing agent formulation with fixed mass concentrations of all substances except the thickener (xanthan gum) is as follows: by mass percentage, 7% sodium tris(trimethylsiloxy)silyloctyl polyoxyethyl butyrate, 8% bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediamine bromide, 15% trisiloxane surfactant UF-5811, 1.5% urea, 1.2% isobutanol, 0.1%-1.3% xanthan gum, 0.8% benzoic acid, and the balance being water. Based on this formulation, the performance of a highly stable and environmentally friendly foam extinguishing agent at different thickener concentrations was tested, such as... Figure 7 As shown in the diagram, when the thickener concentration is below 0.5%, the foam extinguishing agent has a high expansion ratio and diffusion coefficient, but its 25% separation time and anti-burning time are relatively short, while its extinguishing time is relatively long. When the thickener concentration is above 1%, the foam extinguishing agent has a high expansion ratio and diffusion coefficient, but its 25% separation time and anti-burning time are relatively short, while its extinguishing time is relatively long. The foam extinguishing agent exhibits the best overall performance when the thickener concentration is between 0.5% and 1%. Therefore, the optimal concentration range for the thickener is 0.5%-1%.

[0123] Therefore, based on this highly stable and environmentally friendly foam fire extinguishing agent formulation and Figures 4-7 The test results and design examples 5-10 are as follows:

[0124] Example 5

[0125] A highly stable and environmentally friendly foam fire extinguishing agent was prepared using the following method:

[0126] ① Weigh out 25g of the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide, 15g of the trisiloxane surfactant UF-5811, 1g of urea, 0.8g of isobutanol, 0.5g of hydroxyethyl cellulose, and 0.5g of benzoic acid, respectively; ② Take 30g of deionized water, and add the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide, and the trisiloxane surfactant UF-5811 sequentially at 100rpm. 5811 was added to deionized water and stirred for 10 min to obtain a surfactant compound solution; ③ Urea and hydroxyethyl cellulose were mixed evenly in a petri dish; ④ At 50℃ and 2000 rpm, the mixture obtained in ③ was slowly added to the surfactant compound solution and stirred for 90 min; ⑤ Isobutanol and benzoic acid were added to the mixture in ④, 27.2 g of deionized water was added, the mixture was cooled to room temperature, and stirred for 60 min at 1500 rpm to obtain the target foam extinguishing agent stock solution, the appearance of which is shown in the figure below. Figure 8 As shown in the figure, during the 180-day settling period, the stock solution remained a homogeneous liquid without any obvious stratification, precipitation, or solid particle separation, and maintained an overall emulsified state, indicating that the foam extinguishing agent stock solution has good stability.

[0127] Example 6

[0128] A highly stable and environmentally friendly foam fire extinguishing agent was prepared using the following method:

[0129] ① Weigh out 7g of tetrasiloxane surfactant tris(trimethylsiloxy)silyloctyl polyoxyethyl butyrate, 8g of tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide, 1.5g of urea, 1.2g of isobutanol, 1g of xanthan gum, and 0.8g of benzoic acid, respectively; ② Take 40g of deionized water, and add the two tetrasiloxane surfactants sequentially to the deionized water at 100rpm, stirring for 10min to obtain a surfactant compound solution; ③ Mix urea and xanthan gum evenly in a petri dish; ④ At 60℃ and 2000rpm, slowly add the mixture obtained in ③ to the surfactant compound solution, stirring for 90min; ⑤ Continue to add isobutanol and benzoic acid to the mixture in ④, cool to room temperature, add 40.5g of deionized water, stir at 1500rpm for 60min to obtain the target foam extinguishing agent stock solution.

[0130] Example 7

[0131] A highly stable and environmentally friendly foam fire extinguishing agent was prepared using the following method:

[0132] ① Weigh out 20g of tetrasiloxane surfactant tris(trimethylsiloxy)silyloctyl polyoxyethyl butyrate, 15g of trisiloxane surfactant CoatOsil-77, 1g of urea, 0.8g of isobutanol, 0.5g of hydroxyethyl cellulose, and 0.5g of benzoic acid, respectively; ② Take 30g of deionized water, and add the tetrasiloxane surfactant tris(trimethylsiloxy)silyloctyl polyoxyethyl butyrate and the trisiloxane surfactant CoatOsil-77 to the deionized water sequentially at 100rpm, and stir for 10min to obtain a surfactant compound solution; ③ Mix urea and hydroxyethyl cellulose evenly in a petri dish; ④ At 50℃ and 2000rpm, slowly add the mixture obtained in ③ to the surfactant compound solution and stir for 90min; ⑤ Continue to add isobutanol and benzoic acid to the mixture in ④, add 32.2g of deionized water, cool to room temperature, and stir at 1500rpm for 60min to obtain the target foam extinguishing agent stock solution.

[0133] Example 8

[0134] A highly stable and environmentally friendly foam fire extinguishing agent was prepared using the following method:

[0135] ① Weigh out 8g of the tetrasiloxane surfactant tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate, 10g of the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediamine bromide, 10g of the trisiloxane surfactant UF-5811, 1.5g of urea, 1.2g of isobutanol, 1g of xanthan gum, and 0.8g of benzoic acid, respectively; ② Take 40g of deionized water, and add the tetrasiloxane surfactant tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate and bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediamine bromide, respectively, at 100rpm. Oxyethyl-N,N-dimethylethylenediammonium bromide and trisiloxane surfactant UF-5811 were added to deionized water and stirred for 10 min to obtain a surfactant compound solution; ③ Urea and xanthan gum were mixed evenly in a petri dish; ④ The mixture obtained in ③ was slowly added to the surfactant compound solution at 60℃ and 2000 rpm and stirred for 90 min; ⑤ Isobutanol and benzoic acid were added to the mixture in ④, the mixture was cooled to room temperature, 27.5 g of deionized water was added, and the mixture was stirred at 1500 rpm for 60 min to obtain the target foam extinguishing agent stock solution.

[0136] Example 9

[0137] Same as Example 5, except that the amount of tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide is changed from 25g to 15g, and the corresponding amount of water added in step ⑤ is changed from 27.2g to 37.2g.

[0138] Example 10

[0139] Same as Example 6, except that the amount of sodium tris(trimethylsiloxy)silyloctyl polyoxyethylbutyrate, a tetrasiloxane surfactant, is changed from 7g to 10g, and the amount of water added in step ⑤ is changed from 40.5g to 37.5g.

[0140] Comparative Example 3

[0141] Same as Example 5, except that the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide is removed, and the corresponding step ⑤ water replenishment amount is changed from 27.2g to 52.2g.

[0142] Comparative Example 4

[0143] Same as Example 5, except that the amount of tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide used is changed from 25g to 1g, and the corresponding amount of water added in step ⑤ is changed from 27.2g to 51.2g.

[0144] Comparative Example 5

[0145] Same as Example 5, except that all tetrasiloxane surfactants are replaced with hydrocarbon surfactant BS-12.

[0146] Comparative Example 6

[0147] Same as Example 7, except that the amount of sodium tris(trimethylsiloxy)silyloctyl polyoxyethylbutyrate surfactant used in step 5 is changed from 20g to 1g, and the amount of water added in step 5 is changed from 32.2g to 51.2g.

[0148] Comparative Example 7

[0149] Same as Example 7, except that the tetrasiloxane surfactant tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate sodium is replaced with trisiloxane surfactant UF-5811.

[0150] Comparative Example 8

[0151] Same as Example 6, except that the amount of sodium tris(trimethylsiloxy)silyloctyl polyoxyethylbutyrate surfactant used in Example 6 is changed from 7g to 1g, and the amount of water added in step ⑤ is changed from 40.5g to 46.5g.

[0152] Comparative Example 9

[0153] ① Weigh out 8g of the tetrasiloxane surfactant tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate, 10g of the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediamine bromide, 10g of the trisiloxane surfactant UF-5811, 1.5g of urea, 1.2g of isobutanol, 1g of xanthan gum, and 0.8g of benzoic acid, respectively; ② Take 40g of deionized water, and add the tetrasiloxane surfactant tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate and bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediamine bromide sequentially at 100rpm. Dimethyl ethylenediamine bromide and trisiloxane surfactant UF-5811 were added to deionized water and stirred for 10 min to obtain a surfactant compound solution; ③ At 60℃ and 2000 rpm, xanthan gum was slowly added to the surfactant compound solution and stirred for 30 min; ④ At 2000 rpm, urea was added to the mixture in ③ and stirred for 30 min; ⑤ Isobutanol and benzoic acid were added to the mixture in ④, the mixture was cooled to room temperature, 27.5 g of deionized water was added, and the mixture was stirred for 60 min at 1500 rpm to obtain the target foam extinguishing agent stock solution, such as... Figure 9 As shown. The main difference between Comparative Example 9 and Example 8 in the preparation process is that in Comparative Example 9, xanthan gum and urea were added separately in stages, and the stirring time for the xanthan gum and urea addition steps was adjusted from 90 min to 30 min. Figure 9 It can be seen that at day 0, the stock solution was a uniform milky white color with no internal sediment, layering, or bubbles. After 15 days, layering appeared on the upper layer of the stock solution. After 30 days, the stock solution clearly separated into two layers, with a clear upper layer and a viscous lower layer, and a clear interface. This indicates that the prepared foam extinguishing agent sample has poor stability and a short shelf life.

[0154] Based on the extinguishing agent stock solutions described in Examples 5-10 and Comparative Examples 3-8, a 3% foam extinguishing agent solution was obtained by diluting the stock solution with water at a volume ratio of 3:97. Based on the characteristics of fires involving large oil-filled equipment in converter stations (substations) and existing mainstream foam extinguishing systems, a 4.52m... 2A high-temperature transformer oil pool fire source model was used (oil pool dimensions and test procedures were based on standard GB 27897-2011 "Class A Foam Extinguishing Agents"). The initial oil temperature of the high-temperature transformer oil was controlled at 150±5℃. Using a positive pressure foaming system (based on standard GB 27897-2011 "Class A Foam Extinguishing Agents"), the foaming ratio, 25% separation time, extinguishing time, and anti-burning time of the foam extinguishing agent were tested. Simultaneously, the film-forming properties and oil resistance of the foam extinguishing agent solution on the transformer oil surface were tested. The oil resistance and film-forming properties of the foam extinguishing agent were tested using the same methods as the surfactant compound system tests described above. The performance of the foam extinguishing agents in Examples 5-10 and Comparative Examples 3-8 was measured using the above methods, with commercially available 3% AFFF used as a comparison. The test results are shown in Table 2 below. Figures 10-14 As shown:

[0155] Table 2 Performance test data of foam fire extinguishing agent

[0156]

[0157] From Table 2 and Figures 10-14 It is evident that the high-stability environmentally friendly foam fire extinguishing agent of the present invention (Examples 5-10) exhibits superior oil resistance, faster film-forming speed, and shorter extinguishing time compared to comparative examples 3-8; and compared to 3% AFFF, it has a higher foaming ratio, shorter extinguishing time, and longer 25% separation time and fire resistance time. Therefore, the high-stability environmentally friendly foam fire extinguishing agent of the present invention possesses excellent foaming performance, stability, oil resistance, film-forming ability, and fire extinguishing performance. Experimental results show that the foaming ratio of the high-stability environmentally friendly foam fire extinguishing agent is 7-8 times; the 25% separation time is 11.2-15 min; and the film-forming speed is 1.3-1.9 cm. 2 / s, oil resistance is 11.7-14.2min, fire extinguishing time is 54s-98s; fire resistance time is 10min55s-14min30s.

[0158] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly stable and environmentally friendly foam fire extinguishing agent, characterized in that: It contains surfactants; the surfactant mass is 15%-40% of the mass of the high-stability environmentally friendly foam fire extinguishing agent; the surfactants include one or two of the tetrasiloxane surfactants shown in the following structural formulas and a mixture of trisiloxane surfactants; the mass ratio of tetrasiloxane surfactant to trisiloxane surfactant is 15-25:10-15; bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide Sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate; Alternatively, the surfactant comprises a mixture of the above-mentioned tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide and tetrasiloxane surfactant sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate, wherein the mass ratio of the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide to the tetrasiloxane surfactant sodium tri(trimethylsiloxy)silyloctylpolyoxyethylbutyrate is 5-15:5-10.

2. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 1, characterized in that: The trisiloxane surfactant is CoatOsil-77 or DOWSIL. TM One or more of 502W, M-9120, UF-1328, and UF-5811.

3. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 1, characterized in that: The method for preparing the surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide includes the following steps: S1. Under an anhydrous environment, in an organic solvent, using allyl alcohol and 1,2-dibromoethane as raw materials, a reaction is carried out in the presence of anhydrous potassium carbonate to obtain an olefinic ether derivative. S2. Under anhydrous conditions and in an organic solvent, using tris(trimethylsiloxy)silane (Me3SiO)3SiH as a raw material, an alkenyl ether derivative is used and reacted with (Me3SiO)3SiH in the presence of a platinum catalyst to obtain a siloxane compound. S3. In an anhydrous environment and in an organic solvent, using siloxane compounds as raw materials, dimethyl ethylenediamine is used to react and obtain the tetrasiloxane surfactant bis-N-tris(trimethylsiloxy)silylpropoxyethyl-N,N-dimethylethylenediammonium bromide.

4. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 3, characterized in that: The organic solvent in S1 is N,N-dimethylformamide; the organic solvent in S2 is one or a mixture of two of anhydrous tetrahydrofuran and anhydrous dichloromethane; the platinum catalyst in S2 is a cassiterite catalyst; the organic solvent in S3 is one or a mixture of two of anhydrous acetonitrile and anhydrous dichloromethane.

5. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 3, characterized in that: During the reaction of S1, the reaction temperature is 60℃ and the reaction time is 12 hours; during the reaction of S2, the reaction temperature is 40-60℃ and the reaction time is 6-12 hours; during the reaction of S3, the reaction temperature is room temperature and the reaction time is 6-10 hours.

6. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 3, characterized in that: In S1, the mass ratio of allyl alcohol to 1,2-dibromoethane is 5:18; in S2, the mass ratio of tris(trimethylsiloxy)silane to alkenyl ether derivative is 1:1; and in S3, the mass ratio of siloxane compound to dimethylethylenediamine is 20:

4.

7. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 1, characterized in that: The method for preparing the surfactant sodium tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate includes the following steps: S1. Under an anhydrous environment, in an organic solvent, using tris(trimethylsiloxy)silane as a raw material, ethylene oxide is used, and the reaction is carried out under the action of an alkaline reagent to obtain a sodium alkoxide intermediate. S2. Under anhydrous conditions, in an organic solvent, using sodium alkoxide intermediate as raw material, 5-bromopentonitrile is reacted in the presence of a proton buffer to obtain nitrile intermediate; S3. Using nitrile intermediates as raw materials, a strong acid and a strong base are used to react the tetrasiloxane surfactant tris(trimethylsiloxy)silyloctylpolyoxyethylbutyrate sodium salt.

8. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 7, characterized in that: S1 The organic solvent is one or a mixture of two of anhydrous toluene or anhydrous dichloromethane, and the alkaline reagent is triphenylmethyl sodium; S2 The organic solvent is one or a mixture of two of anhydrous dichloromethane and anhydrous tetrahydrofuran, and the proton buffer is one or a mixture of two of sodium carbonate or triethylamine; S3 The strong acid is a 10% (w / w) dilute sulfuric acid solution, and the strong base is a 30% (w / w) sodium hydroxide solution.

9. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 7, characterized in that: In S1, the mass ratio of tris(trimethylsiloxy)silane to ethylene oxide is 20:28; in S2, the mass ratio of sodium alkoxide intermediate to 5-bromopentonitrile is 20:8; and in S3, the mass ratio of nitrile intermediate, strong acid, and strong base is 20:8:

9.

10. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 7, characterized in that: In S1, the reaction temperature is 70°C and the reaction time is 15 hours; in S2, the reaction temperature is room temperature and the reaction time is 10 hours.

11. The highly stable environmentally friendly foam fire extinguishing agent according to any one of claims 1-10, characterized in that: Its raw materials also include cosolvents, organic solvents, thickeners, and preservatives.

12. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 11, characterized in that: Its raw materials, by mass percentage, consist of 15%-40% surfactant, 1%-1.5% cosolvent, 0.8%-1.2% organic solvent, 0.5%-1% thickener, 0.5%-0.8% preservative, with the balance being water.

13. The highly stable and environmentally friendly foam fire extinguishing agent according to claim 12, characterized in that: The cosolvent is urea; the organic solvent is isobutanol; the thickener is one or a mixture of two of hydroxyethyl cellulose and xanthan gum; and the preservative is benzoic acid.

14. A method for preparing a highly stable environmentally friendly foam fire extinguishing agent as described in any one of claims 1-13, characterized in that: This includes mixing surfactants with other raw materials to obtain the highly stable and environmentally friendly foam fire extinguishing agent.

15. The preparation method of the highly stable environmentally friendly foam fire extinguishing agent according to claim 14, characterized in that: Includes the following steps: Take some water, add surfactant, and stir to obtain a surfactant compound solution; The cosolvent and thickener are mixed evenly and added to the surfactant compound solution, and stirred; organic solvent and preservative are added, water is added and stirred to obtain the foam fire extinguishing agent.

16. A fire extinguishing device, characterized in that: It contains a highly stable environmentally friendly foam fire extinguishing agent as described in any one of claims 1-13.

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