CN117486830B

CN117486830B - Fluorocarbon alkyl thioether propyl betaine and preparation method and application thereof

Info

Publication number: CN117486830B
Application number: CN202311840679.0A
Authority: CN
Inventors: 陈超; 钟望; 罗传杰; 张建华; 李纪晖; 康刚; 叶丹妮; 张豫红; 张艺
Original assignee: Chengdu Kehengda Fire Protection Technology Co ltd; Chengdu Kehongda Chemical Co ltd
Current assignee: Chengdu Kehengda Fire Protection Technology Co ltd; Chengdu Kehongda Chemical Co ltd
Priority date: 2023-12-29
Filing date: 2023-12-29
Publication date: 2024-03-22
Anticipated expiration: 2043-12-29
Also published as: CN117486830A

Abstract

The invention discloses fluorocarbon alkyl thioether propyl betaine and a preparation method and application thereof, and belongs to the technical field of fluorocarbon surfactants. The fluorocarbon alkyl thioether propyl betaine has the following structural formula: r is R _f -X-Y-Z; wherein R is _f Is a linear or branched perfluoroalkyl group of C6; x is a C1-C12 straight or branched alkylene group; y is-SCH ₂ CHOH‑N(R ₃ )‑R ₄ -; z is-COO ^‑ ；R ₃ Cycloalkyl of C2-C6, said R ₃ Both ends of the group(s) are linked to the N to form a cyclic secondary amine, R ₄ Is methylene. The fluorocarbon alkyl thioether propyl betaine has the advantages that the group connected with the nitrogen atom is cycloalkyl, the space positioning effect is achieved, and the unstable surface tension caused by space torsion of chain-shaped C-O and C-C is avoided. And the cycloalkyl connected with nitrogen atoms can lead the molecular arrangement to be more orderly and compact, and the surface tension to be lower.

Description

Fluorocarbon alkyl thioether propyl betaine and preparation method and application thereof

Technical Field

The invention relates to a fluorocarbon surfactant, in particular to fluorocarbon alkyl thioether propyl betaine, and a preparation method and application thereof.

Background

The fluorine surfactant has unique three-high and two-hydrophobic properties, namely high surface activity, high heat resistance stability and high chemical stability, and meanwhile, the fluorine-containing hydrocarbon group is hydrophobic and oleophobic. In addition, the fluorine surfactant has good compounding performance with the hydrocarbon surfactant, and the compounding system has higher capability of reducing the surface tension of the solvent, so that the special surfactant plays a unique role in a plurality of fields. The betaine type amphoteric surfactant is a surfactant which is applied earlier, has excellent compounding performance with cationic, anionic and nonionic surfactants, has excellent synergistic effect, is mild in property, has excellent characteristics of good corrosion resistance, sterilization and antistatic property, is easy to biodegrade and the like, and is widely applied to daily chemical industry.

The fluorocarbon betaine surfactant is a structural modification of betaine surfactant, and can show better product performance than betaine surfactant at lower content. Currently, fluorocarbon betaine surfactants are used as key materials in high-efficiency foam extinguishing agents, as wetting agents for the solid or liquid surfaces of hydrocarbons, as dispersants, and as emulsifiers for the emulsion polymerization of fluoroolefins. And the metal surface detergent can be used as a metal surface detergent, an oil displacement agent, a release agent, a fire extinguishing agent, an electroplating intermediate and the like, and has huge market potential.

Since perfluorooctanesulfonyl compounds (PFOS) and perfluorooctanoic acid (PFOA) have bioaccumulation and reproductive toxicity, the european union issued restrictions on the sale and use of PFOS and PFOA in 2006, and thus surfactants of PFOS and PFOA structures are greatly affected. The perfluorohexyl ethyl structural fluorocarbon surfactant is considered to be capable of being naturally degraded, and does not have bioaccumulation and reproduction toxicity, so that the structural surfactant has great application value. The types of betaine with the perfluorohexyl ethyl structure are few in the market at present, so that the surfactant for exploring and developing the betaine with the perfluorohexyl ethyl structure has great economic value.

Application number US20110092735 discloses the synthesis of perfluorohexyl ethyl sulfonamide propyl betaine by the method of: firstly, perfluorohexyl iodide reacts with ethylene under the initiation of BPO to prepare perfluorohexyl ethyl iodide, then perfluorohexyl ethyl iodide reacts with potassium thiocyanate to prepare perfluorohexyl ethyl thiocyanate, then chlorine is used for oxidation to obtain perfluorohexyl ethyl sulfonyl chloride, then the perfluorohexyl ethyl sulfonyl chloride reacts with N, N-dimethyl-1, 3-propanediamine, finally, sodium chloroacetate reacts with sodium chloroacetate, ethanol and water are added for dilution to obtain 27% perfluorohexyl ethyl sulfonamide propyl betaine product, and when the effective content of the product is 0.1% in 2% KCl solution, the surface tension is measured to be 18.0mN/m.

The synthetic route is as follows:

the compound is prepared into 27% of perfluor hexyl ethyl sulfonamide propyl betaine solution, has excellent performance in the fire-fighting field, and has the advantages of low material price and low raw material cost. However, there are also long synthetic routes, resulting in long production cycles; the reaction uses highly toxic gas chlorine, has great research and development difficulty for laboratories, has higher requirements for equipment and qualification during amplified production, and has the defects of high safety risk and the like.

Publication number CN107903180 discloses the synthesis of perfluorohexyl diethyl ether propyl betaine, which comprises the following steps: and (3) reacting a perfluorohexyl ethanol solution containing 12% of perfluorohexyl ethanol sodium with epichlorohydrin to obtain an intermediate, reacting the intermediate with 40% of dimethylamine aqueous solution in an autoclave, distilling out a large amount of perfluorohexyl ethanol, reacting the obtained solution with sodium chloroacetate in isopropanol, adding water, stirring for 1 hour to obtain a product containing 45% of fluorine surfactant, and measuring the surface tension to be 16.9mN/m when the effective content of the product is 0.1%.

The synthetic route is as follows:

the product has excellent performance, short synthetic process route and high atom utilization rate, does not use toxic and harmful chemicals, and integrally meets the requirement of green chemistry. However, the active ingredient of the raw material sodium perfluorohexyl ethanol in the perfluorohexyl ethanol solution only accounts for 12 percent, so that the raw material utilization rate is low; meanwhile, the perfluorohexyl ethanol has higher price and higher raw material cost; although perfluorohexyl ethanol can be recovered by reduced pressure distillation in the second step, the problem of high recovery energy consumption caused by higher boiling point of perfluorohexyl ethanol is also faced.

Publication number CN103237577a discloses an aqueous fire-extinguishing foam with reduced fluorine content, wherein in the disclosed structural formula, two methyl groups are connected behind the N atom, the N atom structure is unshaped, spatial distortion and rotation are easy to occur, the molecular arrangement is not tight, and thus the surface tension of the fluorocarbon surfactant is uncertain because the spatial arrangement is easy to change.

In summary, the perfluorohexyl ethyl betaine fluorocarbon surfactant in the prior art has the technical problems of high raw material cost, high production hazard and the like in the preparation process, and the surface tension also has a reduced space. Therefore, a perfluorohexyl ethyl betaine fluorocarbon surfactant with good safety performance, environmental protection in production and low surface tension is needed to be provided.

Disclosure of Invention

In order to solve the problems, the invention provides the fluorocarbon alkyl thioether propyl betaine, and the preparation method and application thereof, wherein the raw materials are high in reactivity and utilization rate, equipment cost in the preparation method is low, and the obtained fluorocarbon alkyl thioether propyl betaine is lower in surface tension.

In order to achieve the above object, the present invention is achieved by the following technical scheme:

a fluorocarbon alkyl thioether propyl betaine having the structural formula:

R _f -X-Y-Z；

wherein the R is _f A linear or branched perfluoroalkyl group of C6;

x is a C1-C12 straight or branched alkylene group;

y is-SCH ₂ CHOH-CH ₂ -N(R ₃ )-R ₄ -；

Z is-COO ^- ；

The R is ₃ Cycloalkyl of C2-C6, said R ₃ Both ends of the group(s) are linked to the N to form a cyclic secondary amine, R ₄ Is methylene.

Further preferably, said R ₃ Cycloalkyl of C4, said R ₃ Both ends of the group(s) are linked to the N to form a cyclic secondary amine.

The invention also provides a preparation method of the fluorocarbon alkyl thioether propyl betaine, which comprises the following steps:

(1) Adding fluorocarbon alkyl mercaptan and triethylamine into a reactor, emptying the reactor, slowly adding 3-substituted epoxypropane, and reacting for 6-8 hours at 20-30 ℃ to obtain an intermediate B, wherein the reaction formula is as follows:

(2) Adding isopropanol and cyclic secondary amine into the intermediate B obtained in the step (1), reacting for 12-16 hours at the temperature of 40-50 ℃, adding alkali, stirring, concentrating the reaction liquid until the reaction liquid is dry, adding an organic solvent, pulping, filtering, washing, and concentrating the filtrate to obtain a light yellow liquid, namely an intermediate C, wherein the reaction formula is as follows:

(3) Adding the intermediate C into sodium chloroacetate solution, adding isopropanol, heating and refluxing for reaction for 10-12h, concentrating the reaction solution under reduced pressure, and recrystallizing to obtain a white solid product, namely fluorocarbon alkyl thioether propyl betaine, wherein the reaction formula is as follows:

further, in the reaction formulae of step (1), step (2) and step (3), n is 1, or 2, or 3, or 4.

Further, m is 0, or 1, or 2, or 3, or 4 in the reaction formulae of step (2) and step (3).

Further, in the reaction formula of step (1) and step (2), X is Cl, br, or OTf.

Further, the cyclic secondary amine in the step (2) is a cyclic secondary amine of C2-C6.

Further, the 3-substituted propylene oxide in the step (1) is added in a slow dropwise manner.

Further, the reaction temperature of the intermediate C and isopropanol in the step (3) in the sodium chloroacetate solution is 70-90 ℃.

Further, the addition amount of the triethylamine in the step (1) is 0.2-3% of the mass of fluorocarbon alkyl mercaptan; the addition amount of the 3-substituted epoxypropane is 20-30% of the mass of the fluorocarbon alkyl mercaptan.

Further, in the step (2), the addition amount of the isopropanol is 100% of the mass of the fluorocarbon alkyl mercaptan, and the addition amount of the cyclic secondary amine is 10% -60% of the mass of the fluorocarbon alkyl mercaptan.

Further, the alkali used in the step (2) is sodium hydroxide or sodium carbonate, and the addition amount of the alkali is 20-40% of the mass of the fluorocarbon alkyl mercaptan.

Further, in the pulping of the organic solvent in the step (2), the organic solvent is petroleum ether, heptane, or toluene. The addition amount of the organic solvent is 100-300% of the mass of the fluorocarbon alkyl mercaptan.

Further, in the step (3), the mass fraction of the sodium chloroacetate solution is 10% -30%.

The invention also protects an application of the fluorocarbon alkyl thioether propyl betaine.

The fluorocarbon alkyl thioether propyl betaine is used as a foam extinguishing agent for fire control.

The fluorocarbon alkyl thioether propyl betaine is used in a foam fire extinguishing agent composition for fire control.

Further, when the fluorocarbon alkyl thioether propyl betaine is used in the foam fire extinguishing agent composition for fire control, the fluorocarbon alkyl thioether propyl betaine accounts for 0.1 to 10 percent of the mass of the foam fire extinguishing agent composition for fire control.

The fluorocarbon alkyl thioether propyl betaine and the preparation method and application thereof have the beneficial effects that:

(1) Because of adopting specific production raw materials, the raw materials have high activity. The fluorocarbon alkyl mercaptan has high activity, replaces perfluorohexyl ethanol, can react with epoxy chloropropane under the catalysis of a small amount of triethylamine, and avoids the use of strong alkali sodium ethoxide; meanwhile, excessive raw materials are avoided being used as solvents, and the production cost is increased due to the fact that the raw materials are recycled.

(2) The intermediate B is thoroughly reacted, and the obtained intermediate B has high purity and does not need post-treatment, so that continuous feeding of the reaction can be realized, the production time is shortened, and the production cost is reduced.

(3) The atomic utilization rate is high, and the fluorocarbon raw material can be completely converted into a target product. In the synthesis process, no toxic and harmful raw materials are used, so that the production difficulty is greatly reduced.

(4) The fluorocarbon alkyl thioether propyl betaine has the advantages that the group connected with the nitrogen atom is cycloalkyl, the space positioning effect is achieved, and the unstable surface tension caused by space torsion of chain-shaped C-O and C-C is avoided. And the cycloalkyl group connected with nitrogen atoms can lead the molecular arrangement to be more orderly and compact, and can lead the surface tension to be lower.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.

FIG. 1 is a nuclear magnetic resonance spectrum of fluorocarbon alkyl sulfide propyl betaine obtained in example 1 of the present invention;

FIG. 2 is a fluorine spectrum of fluorocarbon alkyl thioether propyl betaine obtained in example 1 of the present invention;

FIG. 3 is a LCMS spectrum of fluorocarbon alkyl sulfide propyl betaine obtained in example 1 of the present invention.

Detailed Description

In order that the manner in which the invention may be better understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

A fluorocarbon alkyl thioether propyl betaine having the structural formula:

R _f -X-Y-Z；

wherein the R is _f A linear or branched perfluoroalkyl group of C6;

x is a C1-C12 straight or branched alkylene group;

y is-SCH ₂ CHOH-CH ₂ -N(R ₃ )-R ₄ -；

Z is-COO ^- ；

R ₃ Cycloalkyl of C2-C6, R ₃ Both ends of the group (A) are linked to N atoms to form a cyclic secondary amine, R ₄ Is methylene.

As a preference, R ₃ Cycloalkyl of C4, R ₃ Both ends of the group(s) are linked to an N atom to form a cyclic secondary amine.

As a preference, X is a C1-C4 linear or branched alkylene radical.

The fluorocarbon alkyl thioether propyl betaine has the following structural formula:

a preparation method of fluorocarbon alkyl thioether propyl betaine, which comprises the following steps:

example 1

(1) Adding perfluorohexyl ethanethiol and triethylamine into a reactor, evacuating the reactor through nitrogen replacement, slowly dropwise adding epoxy chloropropane at 30 ℃, and reacting for 8 hours at 30 ℃ after dropwise adding to obtain an intermediate B with the product purity of 92.9%;

(2) Adding isopropanol and tetrahydropyrrole into the intermediate B obtained in the step (1), heating to 50 ℃, reacting for 12 hours at the temperature of 50 ℃ to obtain a reaction liquid, adding sodium carbonate, concentrating the reaction liquid, adding n-heptane, pulping, filtering, washing, and concentrating the filtrate to obtain a light yellow liquid, namely an intermediate C;

(3) And adding the intermediate C into a sodium chloroacetate solution, adding isopropanol, heating to 75 ℃ for reflux reaction for 12 hours, concentrating the reaction solution under reduced pressure, and recrystallizing to obtain a white solid product, namely the fluorocarbon alkyl thioether propyl betaine.

Example 2

(1) Adding perfluorohexyl ethanethiol and triethylamine into a reactor, evacuating the reactor through nitrogen replacement, slowly dropwise adding epoxy chloropropane at 20 ℃, and reacting for 6 hours at 20 ℃ after dropwise adding to obtain an intermediate B;

(3) And adding the intermediate C into a sodium chloroacetate solution, adding isopropanol, heating to 80 ℃ for reflux reaction for 12 hours, concentrating the reaction solution under reduced pressure, and recrystallizing to obtain a white solid product, namely the fluorocarbon alkyl thioether propyl betaine.

Example 3

(1) Adding perfluorohexyl methyl mercaptan and triethylamine into a reactor, evacuating the reactor through nitrogen replacement, slowly dropwise adding epoxy chloropropane at 20 ℃, and reacting for 6 hours at 20 ℃ after dropwise adding to obtain an intermediate B;

(2) Adding isopropanol and tetrahydropyrrole into the intermediate B obtained in the step (1), heating to 40 ℃, reacting for 16 hours at the temperature of 40 ℃ to obtain a reaction liquid, adding sodium carbonate, concentrating the reaction liquid, adding n-heptane, pulping, filtering, washing, and concentrating the filtrate to obtain a light yellow liquid, namely an intermediate C;

Example 4

(1) Adding perfluorohexyl propanethiol and triethylamine into a reactor, evacuating the reactor through nitrogen replacement, slowly dropwise adding epoxy chloropropane at 20 ℃, and reacting for 6 hours at 20 ℃ after dropwise adding to obtain an intermediate B;

Example 5

(1) Adding perfluorohexyl butyl mercaptan and triethylamine into a reactor, evacuating the reactor through nitrogen replacement, slowly dropwise adding epoxy chloropropane at 20 ℃, and reacting for 6 hours at 20 ℃ after dropwise adding to obtain an intermediate B;

Example 6

(2) Adding isopropanol and C2 cyclic secondary amine into the intermediate B obtained in the step (1), heating to 40 ℃, reacting for 16 hours at the temperature of 40 ℃ to obtain a reaction solution, adding sodium carbonate, concentrating the reaction solution, adding n-heptane, pulping, filtering, washing, and concentrating the filtrate to obtain a light yellow liquid, namely the intermediate C;

Example 7

(2) Adding isopropanol and C3 cyclic secondary amine into the intermediate B obtained in the step (1), heating to 40 ℃, reacting for 16 hours at the temperature of 40 ℃ to obtain a reaction solution, adding sodium carbonate, concentrating the reaction solution, adding n-heptane, pulping, filtering, washing, and concentrating the filtrate to obtain a light yellow liquid, namely the intermediate C;

Example 8

(2) Adding isopropyl alcohol and C5 cyclic secondary amine into the intermediate B obtained in the step (1), heating to 40 ℃, reacting for 16 hours at the temperature of 40 ℃ to obtain a reaction solution, adding sodium carbonate, concentrating the reaction solution, adding n-heptane, pulping, filtering, washing, and concentrating the filtrate to obtain a light yellow liquid, namely the intermediate C;

Example 9

(2) Adding isopropanol and C6 cyclic secondary amine into the intermediate B obtained in the step (1), heating to 40 ℃, reacting for 16 hours at the temperature of 40 ℃ to obtain a reaction solution, adding sodium carbonate, concentrating the reaction solution, adding n-heptane, pulping, filtering, washing, and concentrating the filtrate to obtain a light yellow liquid, namely the intermediate C;

Characterization of Compounds

The final product obtained in example 1 was analyzed by nuclear magnetic resonance spectroscopy, and the obtained spectrum is shown in FIG. 1. As can be seen from fig. 1, the nuclear magnetic analysis thereof is:

¹ HNMR(400MHz,Methanol-d4)δ4.22(dtd,J＝10.2,5.9,1.8Hz,1H),4.06-3.82(m,5H),3.71(dt,J＝11.6,7.0Hz,2H),3.55(dd,J＝13.4,10.1Hz,1H),2.92-2.80(m,2H),2.762.62(m,2H),2.60-2.42(m,2H),2.17(t,J＝4.2Hz,4H)。

the final product obtained in example 1 was analyzed by fluorine spectrum, and the obtained spectrum is shown in fig. 2.

As can be seen from fig. 2, the nuclear magnetic analysis thereof is:

¹⁹ FNMR(376MHz,MeOD)δ-82.45,-115.30,-122.96,-123.94,-124.41,-127.36。

the final product obtained in example 1 was analyzed by LCMS and the spectrum obtained is shown in fig. 3. As can be seen from fig. 3, LCMS analysis thereof is:

LCMS (ELSD, acid) spectra show: [ M+H ]] ⁺ = 566.0, and C17H20F13NO3S m/z= 565.0, analyzed as target molecular weight.

And determining the structure of the fluorocarbon alkyl thioether propyl betaine as a target product by combining a nuclear magnetism hydrogen spectrum, a fluorine spectrum and LCMS.

Application evaluation

Control 1: the mass components and the proportion of the water are 27 percent of perfluorohexyl ethyl sulfonamide propyl betaine, 30 percent of glycol and the balance of water.

Control 2: the weight components and the proportion of the components are 27 percent of perfluorooctyl ethyl sulfonamide sweet propyl vegetable alkali, 30 percent of glycol and the balance of water.

Control 3: the mass components and the proportion of the water are 27 percent of perfluorobutyl sulfonamide propyl betaine, 30 percent of glycol and the balance of water.

Control 4: the mass components and the proportion of the components are 27 percent of perfluorohexyl diethyl ether propyl betaine, 30 percent of glycol and the balance of water.

Preparing sample liquid 1# -14# of fluorocarbon alkyl thioether propyl betaine, wherein the mass components of the sample liquid 1# -14# are 27% of fluorocarbon alkyl thioether propyl betaine, 30% of ethylene glycol and the balance of water respectively. Comparing with reference 1-4;

diluting sample solutions prepared from reference substances 1-4 and 1# -14# fluorocarbon alkyl thioether propyl betaine with deionized water for 2000 times, and measuring the surface tension of each diluted solution to obtain the results shown in Table 1:

table 1 results of performance comparisons

From the surface tension test results in Table 1, it was found that the surface tension of the controls 1 to 4 was generally between 17 and 18mN/m, the control 1 was at a minimum 16.31mN/m, and the surface tension of the sample solution 6# (fluorocarbon alkyl thioether propyl betaine) was 16.57mN/m, which was similar to that of the control 1; however, the synthetic route of the reference substance 1 is longer, the production period is long, meanwhile, the highly toxic gas chlorine is needed in the reaction process, the requirements on the production conditions are severe, and the safety risk is high. The fluorocarbon alkyl thioether propyl betaine has simpler production process, high safety performance and unexpected effect. From the results of the interfacial tension test in Table 1, it was found that the interfacial tension of sample solution # 6 (fluorocarbon alkyl thioether propyl betaine) was 0.96mN/m, and that the interfacial tension of control 1 and control 4 was 1.2-1.3mN/m. The interfacial tension of the reference substance 2 and the reference substance 3 is 1.4-1.6mN/m. The sample liquid 6# (fluorocarbon alkyl thioether propyl betaine) has extremely low surface tension and relatively lower interfacial tension, the surface tension and the interfacial tension are two most important indexes for measuring the spreadability of the foam liquid on the surface of the fuel, and the lower surface tension and the interfacial tension enable the spreading coefficient of the foam on the oil fuel to be larger, so that the foam can rapidly cover the combustion surface of the oil fuel in the fire extinguishing process and isolate air, thereby achieving the aim of rapidly extinguishing the fire.

Fire extinguishing performance test

Sample liquid 6# and the control products 1, 2, 3 and 4 are respectively prepared into corresponding fire extinguishing agent compositions.

The fire extinguishing agent composition comprises the following components in parts by weight: 8% hydrocarbon blowing agent, 3% diethylene glycol butyl ether, 0.6% fluorocarbon surfactant solution (test sample), balance water. The prepared fire extinguishing agent composition is respectively tested for foaming performance, fire extinguishing performance and burning resistance according to the requirements of a foam fire extinguishing agent (GB/T15308-2006), and the obtained data are shown in Table 2;

TABLE 2 foaming, fire extinguishing and burn resistance test results

Sample name	Expansion ratio of foaming	Extinguishing time of fire	Burn time resistance
				Reference substance 1	7.74	1min52s	16min20s
Reference substance 2	7.71	1min59s	17min20s
				Reference substance 3	7.77	2min01s	12min30s
Control 4	7.81	1min58s	15min55s
				Sample solution 6#	7.79	1min52s	17min05s

As can be seen from Table 2, the foaming times were all 7.7 to 7.8 for the respective test samples.

The fire extinguishing experiment shows that the fire extinguishment is completed in 1min52s for both the control substance 1 and the sample liquid 6. The rest samples are about 2 minutes, which shows that the fire extinguishing rate of the invention is good.

The burn-resistant experiment shows that the burn-resistant time of the reference substance 2 and the sample liquid 6# is longer and respectively 17min20s and 17min05s, and both are more than 17min, but the fluorocarbon surfactant of the reference substance 2 introduces toxic gas in the synthesis process, so that the production process is difficult and the process is complex. The rest samples, reference 1, reference 4, reference 3 and reference 3 are respectively 16min and 20s, 15min and 55s and 12min and 30s, respectively.

The comprehensive test results show that the fluorocarbon alkyl thioether propyl betaine has long burning resistance time, rapid fire extinguishing, and all properties in the optimal and the front of the control sample, and the comprehensive performance reaches or exceeds that of the control sample.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

Finally, it should be noted that: the embodiment of the invention is disclosed only as a preferred embodiment of the invention, and is only used for illustrating the technical scheme of the invention, but not limiting the technical scheme; although the invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that; the technical scheme recorded in the various embodiments can be modified or part of technical features in the technical scheme can be replaced equivalently; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims

1. A kind of fluorocarbon alkyl sulfide propyl betaine, which is characterized in that: it has the following structural formula:

R _f -XYZ;

Wherein, the R _f is a C6 linear perfluoroalkyl group;

X is a C1-C12 linear alkylene group;

Y is -SCH ₂ CHOH-CH ₂ -N(R ₃ )-R ₄ -;

Z is -COO ^- ;

The R ₃ is a C2-C6 cycloalkyl group, both ends of the R ₃ group are connected to the N to form a cyclic secondary amine, and R ₄ is a methylene group.

2. Fluorocarbon alkyl sulfide propyl betaine according to claim 1, characterized in that: the R ₃ is a C4 cycloalkyl group, and both ends of the R ₃ group are connected to the N to form Cyclic secondary amine.

3. A method for preparing fluorocarbon alkyl sulfide propyl betaine according to any one of claims 1-2, characterized in that: it includes the following steps:

(1) Add fluorocarbon alkylmercaptan and triethylamine to the reactor, empty the reactor, slowly add 3-substituted propylene oxide, and react at 20°C-30°C for 6h-8h to obtain intermediate B , its reaction formula is:

;

(2) Add isopropanol and cyclic secondary amine to intermediate B obtained in step (1), react at 40°C-50°C for 12h-16h, add alkali and stir, the reaction solution is concentrated to dryness, and an organic solvent is added After beating, filtering and washing, the filtrate is concentrated to obtain a light yellow liquid, which is intermediate C. The reaction formula is:

;

(3) Add intermediate C to the sodium chloroacetate solution, then add isopropyl alcohol, raise the temperature and reflux for 10h-12h, concentrate the reaction solution under reduced pressure, and then recrystallize to obtain a white solid product, which is fluorocarbon alkyl sulfide. Propyl betaine, its reaction formula is:

;

In the reaction formulas of steps (1) and (2), X is Cl, or Br, or OTf;

In the reaction formulas of step (1), step (2) and step (3), n is 1, or 2, or 3, or 4; in the reaction formulas of step (2) and step (3), m is 0, or 1 , or 2, or 3, or 4.

4. The preparation method of fluorocarbon alkyl sulfide propyl betaine according to claim 3, characterized in that: the cyclic secondary amine in step (2) is a C2-C6 cyclic secondary amine.

5. The preparation method of fluorocarbon alkyl sulfide propyl betaine according to claim 3, characterized in that: the reaction temperature of intermediate C and isopropyl alcohol in the sodium chloroacetate solution in step (3) is 70°C. -90℃.

6. The preparation method of fluorocarbon alkyl sulfide propyl betaine according to claim 3, characterized in that: the addition amount of triethylamine in step (1) is 0.2% of the mass of fluorocarbon alkyl mercaptan. -3%; the addition amount of the 3-substituted propylene oxide is 20%-30% of the mass of the fluorocarbon alkyl mercaptan.

7. The preparation method of fluorocarbon alkyl sulfide propyl betaine according to claim 3, characterized in that: the addition amount of isopropanol in step (2) is 100% of the quality of fluorocarbon alkyl mercaptan. , the addition amount of the cyclic secondary amine is 10%-60% of the mass of the fluorocarbon alkyl mercaptan.

8. An application of fluorocarbon alkyl sulfide propyl betaine according to claim 1, characterized in that it is used as a fire-fighting foam fire-extinguishing agent or in a fire-fighting foam fire-extinguishing agent composition.