A quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain and a preparation method thereof

Abstract

The invention discloses a quaternary ammonium surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain and a preparation method thereof, wherein the preparation method is by N-((dimethylamino) methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl) hexanoamide, 3-chloropropylmethyldimethoxysilane, potassium iodide and solvent in a reaction vessel, heating and stirring are completely dissolved to raw material, temperature reaction is continued afterwards, solvent and water are removed by decompression distillation after the reaction terminates, and washed with ethanol until washings do not change color, to obtain a quaternary ammonium surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain;The surfactant is free of perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS) substances, possesses environmentally friendly characteristics, will not have an impact on human nervous system, immune system, endocrine system and genetic information etc., can effectively produce foam, with good heat stability, it is possible to improve the foaming performance and the burning resistance of foam fire extinguishing agent. Wetting agent aspect can reduce aqueous solution surface tension, wets low-energy surface.

Description

Technical Field

[0001] The present invention relates to a surfactant and a preparation method thereof, in particular to a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain and a preparation method thereof, belonging to the technical field of surfactants. Background Art

[0002] Fluorocarbon surfactants are a special and important class of fine chemicals, often called "super surfactants." Fluorocarbon surfactants possess excellent thermal and chemical stability, high gas solubility, strong hydrophobic and oleophobic properties, and high surface activity. The most commonly used fluorocarbon surfactants are perfluorooctane sulfonates (PFOS) and perfluorooctanoic acid and its salts (PFOA). Unfortunately, PFOS / PFOA compounds are difficult to degrade in the natural environment, are not only neurotoxic, but also have the potential to accumulate in the biosphere. Against this backdrop, the use and production of PFOS / PFOA compounds are gradually being restricted. Therefore, the development of new fluorocarbon surfactants that are less environmentally friendly, non-bioaccumulative, and biodegradable is of great significance. Numerous researchers have explored strategies for developing high-performance, non-long-chain fluorocarbon surfactants, including ① shortening the fluorocarbon chain length, ② branching the fluorocarbon chain, and ③ introducing heteroatoms into the fluorocarbon chain. However, only a few new fluorocarbon surfactants have been proposed in China. Furthermore, these proposed new fluorocarbon surfactants have a limited structure and utilize only the ① strategy (reducing the fluorocarbon chain length from 8 to 6). Almost all new fluorocarbon surfactants use a 6-carbon fluorinated chain as the hydrophobic group, such as perfluorohexylsulfonyl fluoride and perfluorohexylsulfonyl chloride. However, the production process for these fluorocarbon surfactants is complex, with low yields and harsh reaction conditions. Very few fluorocarbon surfactants with new fluorocarbon chain structures have been proposed, and gemini fluorocarbon surfactants and fluorocarbon surfactants with mixed hydrophobic chains (fluorocarbon chain-silicon carbon chain) are even less common.

[0003] In summary, current new fluorinated surfactants have the following problems: limited variety, single structure, complex preparation process, harsh reaction conditions, low yield, and significant environmental hazards. Therefore, there is an urgent need for a fluorinated surfactant with simple preparation process, cheap and readily available raw materials, and excellent performance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the above existing technologies and propose a quaternary ammonium salt surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain and a preparation method thereof. Through a simple and mild preparation method, a surfactant is obtained that can significantly reduce the surface tension of aqueous solutions, generate a large amount of foam, and wet low-energy surfaces.

[0005] The technical solution of the present invention to solve the above technical problems is:

[0006] A quaternary ammonium surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, the structural formula of the surfactant is:

[0007]

[0008] The present invention also provides a method for preparing a quaternary ammonium surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, specifically:

[0009] N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide, 3-chloropropylmethyldimethoxysilane, potassium iodide and a solvent are added to a reaction vessel, heated and stirred until the raw materials are completely dissolved, and then the temperature is continued to react. After the reaction is completed, the solvent and water are removed by distillation under reduced pressure, and the washing liquid is washed with ethanol until the washing liquid does not change color to obtain a quaternary ammonium surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain. The chemical reaction formula is as follows:

[0010]

[0011] The technical solution further defined in the present invention is:

[0012] Furthermore, in the preparation method of the aforementioned quaternary ammonium surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, the molar ratio of N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide:3-chloropropylmethyldimethoxysilane:potassium iodide is 1:(1.0-2.0):(0.01-0.03);

[0013] Preferably, the molar ratio of N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide:3-chloropropylmethyldimethoxysilane:potassium iodide is 1:1.5:0.02.

[0014] In the preparation method of the aforementioned quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon dual hydrophobic chain, the solvent is one of acetonitrile, toluene, benzene, cyclohexane, chloroform, acetone, N,N-dimethylacetamide or N,N-dimethylformamide;

[0015] Preferably, the solvent is acetonitrile.

[0016] In the preparation method of the quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, the temperature of heating and stirring is 30-50°C;

[0017] Preferably, the temperature for heating and stirring is 40°C.

[0018] In the above-mentioned preparation method of the quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon dual hydrophobic chain, the temperature of the temperature-elevated reaction is 60-90°C; preferably, the temperature of the temperature-elevated reaction is 75°C.

[0019] In the aforementioned method for preparing the quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon dual hydrophobic chain, the temperature-raising reaction time is 4-8 hours; preferably, the temperature-raising reaction time is 6 hours.

[0020] The beneficial effects of the present invention are:

[0021] (1) The new quaternary ammonium surfactant with fluorocarbon-silicon-carbon double hydrophobic chain does not contain perfluorooctanoic acid (PFOS) and perfluorohexane sulfonate (PFH x S), the product is environmentally friendly, has little impact on the environment, and will not affect the human nervous system, immune system, endocrine system and genetic information.

[0022] (2) The raw materials used in the present invention are fluorinated alkyl amides, while the raw materials of existing fluorocarbon surfactants are generally perfluoroalkyl sulfonyl halides. Not only is the price of the raw materials lower, but also no inorganic acids such as HR (R=F, Cl, Br, I) are produced during the production process, and the synthesis route is more environmentally friendly.

[0023] (3) The fluorocarbon surfactant of the present invention contains two hydrophobic chains, a fluorocarbon chain and a silicon-carbon chain, which can reduce the surface tension of the aqueous solution, have high foaming properties and thermal stability, and can be used as a foaming agent and foam stabilizer for fire-fighting foam, and can effectively improve the foaming, fire extinguishing and fire resistance of the foam fire extinguishing agent.

[0024] (4) The fluorocarbon surfactant of the present invention has good chemical stability and can wet low-energy surfaces well at low concentrations when used as a wetting agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be described clearly and completely below with reference to specific embodiments. It should be understood that the embodiments described are merely some, and not all, of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0027] Example 1

[0028] This embodiment provides a method for preparing a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, comprising the following steps:

[0029] N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide, 3-chloropropylmethyldimethoxysilane, potassium iodide and acetonitrile were added to a reaction vessel, wherein the molar ratio of N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide:3-chloropropylmethyldimethoxysilane:potassium iodide was

[0030] 1:1.5:0.02, stirred at 40 ° C until the raw materials were completely dissolved, then continued to heat to 75 ° C for 6 hours, and after the reaction, acetonitrile was removed by vacuum distillation, and washed with ethanol until the washing liquid did not change color to obtain a quaternary ammonium surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain.

[0031] The nuclear magnetic resonance hydrogen spectrum of the quaternary ammonium salt surfactant with fluorocarbon-silicon-carbon double hydrophobic chains in Example 1 is as follows: Figure 1 As shown, the NMR spectrum is consistent with the structure of the target product.

[0032] Example 2

[0033] This embodiment provides a method for preparing a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, comprising the following steps:

[0034] N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide, 3-chloropropylmethyldimethoxysilane, potassium iodide and toluene are added to a reaction vessel, wherein the molar ratio of N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide:3-chloropropylmethyldimethoxysilane:potassium iodide is

[0035] 1:1.0:0.01, stirring at 30℃ until the raw materials are completely dissolved, then continuing to heat to 60℃ for 4h. After the reaction, toluene is removed by distillation under reduced pressure, and washing with ethanol until the washing liquid does not change color to obtain a quaternary ammonium surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain.

[0036] Example 3

[0037] This embodiment provides a method for preparing a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, comprising the following steps:

[0038] N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide, 3-chloropropylmethyldimethoxysilane, potassium iodide and cyclohexane are added to a reaction vessel, wherein the molar ratio of N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide:3-chloropropylmethyldimethoxysilane:potassium iodide is 1:2.0:0.03, and the mixture is stirred at 50°C until the raw materials are completely dissolved. The temperature is then continuously raised to 90°C for reaction for 8 hours. After the reaction is completed, the cyclohexane is removed by distillation under reduced pressure, and the mixture is washed with ethanol until the washing liquid does not change color to obtain a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain.

[0039] Example 4

[0040] This embodiment provides a method for preparing a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, comprising the following steps:

[0041] N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide, 3-chloropropylmethyldimethoxysilane, potassium iodide and chloroform are added to a reaction vessel, wherein the molar ratio of N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide:3-chloropropylmethyldimethoxysilane:potassium iodide is

[0042] 1:1.0:0.01, stirring at 30°C until the raw materials are completely dissolved, then continuing to heat to 90°C for 8 hours. After the reaction, chloroform is removed by distillation under reduced pressure, and washing with ethanol until the washing liquid does not change color to obtain a quaternary ammonium surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain.

[0043] Example 5

[0044] This embodiment provides a method for preparing a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, comprising the following steps:

[0045] N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide, 3-chloropropylmethyldimethoxysilane, potassium iodide and acetone were added to a reaction vessel, wherein the molar ratio of N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide:3-chloropropylmethyldimethoxysilane:potassium iodide was

[0046] 1:2.0:0.03, stirring at 50°C until the raw materials are completely dissolved, then continuing to heat to 60°C for 4 hours. After the reaction, acetone is removed by distillation under reduced pressure, and washing is carried out with ethanol until the washing liquid does not change color to obtain a quaternary ammonium surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain.

[0047] Surface tension test sample preparation: The fluorocarbon surfactants in Examples 1-5 were prepared into aqueous solutions at 0.005 mg / mL, 0.002 mg / mL, and 0.001 mg / mL, respectively. Commercially available perfluorooctylsulfonyl quaternary ammonium salt surfactant (PFOS) and commercially available betaine-type fluorocarbon surfactant (FS-50) were also prepared into solutions at the above concentrations.

[0048] Experimental design: According to the ring-pull method in GB / T 22237-2008, the surface tension of the new quaternary ammonium surfactant with fluorocarbon-silicon-carbon double hydrophobic chains was measured using an SFZL-A series automatic surface tension tester (Shanghai Yingnuo Precision Instrument Co., Ltd.).

[0049] The test results are shown in Table 1:

[0050] Table 1 Surface tension of aqueous solutions of various substances at different concentrations (mN / m)

[0051]

[0052] As can be seen from Table 1, although the surface tension of the quaternary ammonium salt surfactants with fluorocarbon-silicon-carbon double hydrophobic chains obtained in Examples 1-5 is higher than that of imported PFOS at high concentrations (concentration of 0.005 mg / mL), when the concentration is reduced to below 0.002 mg / mL, the surface tension of the new sulfonate anionic surfactant containing double fluorocarbon short chains is lower than that of imported PFOS and PFOA. This shows that the fluorocarbon surfactants of the present invention outperform imported PFOS and PFOA at low concentrations. In addition, the surface tension of the fluorocarbon surfactants of the present invention at the same concentration is significantly lower than that of commercially available FS-50, that is, the fluorocarbon surfactants of the present invention have stronger surface activity.

[0053] Preparation of contact angle test samples: The fluorocarbon surfactants in Examples 1-5 were prepared at 0.005 mg / mL, 0.002 mg / mL, 0.001 mg / mL, 5×10 -4 mg / mL and 2×10 -4 mg / mL aqueous solution; commercially available perfluorooctyl sulfonyl quaternary ammonium salt surfactant (PFOS) and commercially available betaine type fluorocarbon surfactant (FS-50) were also prepared into solutions of the above concentrations.

[0054] Experimental design: According to the contact angle method in GB / T 30693-2014, a JCY-3 contact angle meter (Shanghai Fangrui Instrument Co., Ltd.) was used to measure the contact angle of a new quaternary ammonium surfactant solution with a fluorocarbon-silicon-carbon dual hydrophobic chain using a polytetrafluoroethylene plate (PTFE, an ultra-low surface energy hydrophobic material) as the test substrate.

[0055] The test results are shown in Table 2:

[0056] Table 2 Contact angles of aqueous solutions of various substances at different concentrations (°)

[0057]

[0058] As can be seen from Table 2, the contact angles of Examples 1-5 are lower than those of imported PFOS and commercial FS-50, which indicates that the wetting performance of the quaternary ammonium surfactant solution with fluorocarbon-silicon-carbon double hydrophobic chains is better than that of PFOS and FS-50. Moreover, when the concentration is reduced to 2×10 -4 At a concentration of 2×10 PFOS, the contact angles of imported PFOS and commercial FS-50 were 88.45 and 94.32, respectively. This indicates that at this concentration, imported PFOS can hardly wet the PTFE plate, while commercial FS-50 can no longer wet the PTFE plate. However, the fluorosilicone surfactant of the present invention can wet the PTFE plate at a concentration of 2×10 -4 When the concentration of fluorosilicone surfactant is 0.1 mg / mL, the contact angle is about 44-46°, and the PTFE plate can be well wetted. This shows that the fluorosilicone surfactant of the present invention not only has excellent wetting properties, but also has a low usage concentration.

[0059] Preparation of Foaming Power and Foaming Stability Test Samples: The fluorocarbon surfactants in Examples 1 and 2 were prepared into aqueous solutions at concentrations of 0.01 mg / mL, 0.005 mg / mL, 0.002 mg / mL, and 0.001 mg / mL, respectively. A commercially available perfluorooctylsulfonyl quaternary ammonium salt surfactant (PFOS) and a commercially available betaine-type fluorocarbon surfactant (FS-50) were also prepared into solutions at the above concentrations.

[0060] Experimental design: According to the improved Ross-Miles method in GB / T 7462-1994, the foaming power of a new quaternary ammonium surfactant solution with a fluorocarbon-silicon-carbon double hydrophobic chain was measured at room temperature (25°C) using an improved Ross foam instrument (Shenzhen Sanli Technology Co., Ltd.). The foam height was observed 30 seconds and 5 minutes after the liquid flow stopped. The foam height h0 at 30 seconds was used as the measure of the foaming power, and the residual foam ratio R5 was used as the measure of the foaming stability (R5 = h0 / h5).

[0061] The test results are shown in Table 3, Table 4 and Table 5:

[0062] Table 3 Foam height h0 (mm) of various substance solutions at different concentrations at 30s

[0063]

[0064] Table 4 Foam height h5 (mm) of each substance solution at different concentrations in 5 minutes

[0065]

[0066] Table 5 Residual foam ratio R5 (%) of each substance at different concentrations

[0067]

[0068] As can be seen from the foam height of Example 1 and Example 2 in Table 3, when solution concentration was higher (0.01mg / mL and 0.005mg / mL), the foaming power of the novel quaternary ammonium salt surfactant with fluorocarbon-silicon-carbon double hydrophobic chains of the present invention was approximately equal, but when concentration decreased (0.002mg / mL and 0.001mg / mL), foaming power had a larger decline. The data in Comparative Table 3 can be found that no matter it is high concentration or low concentration, the foaming power of fluorosilicone surfactant of the present invention is all higher than import PFOS and commercially available FS-50. The data in Comparative Table 5 can be found that no matter it is fluorosilicone surfactant of the present invention, or import PFOS and commercially available FS-50, the residual foam is than all presenting the trend that reduces along with concentration reduction. And, it can be clearly seen that the residual foam of fluorosilicone surfactant of the present invention is than far higher than import PFOS and commercially available FS-50, and namely fluorosilicone surfactant of the present invention has better foaming stability.

[0069] The fluorosilicone surfactant of the present invention does not contain perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS) substances, has environmentally friendly characteristics, will not affect the human nervous system, immune system, endocrine system and genetic information, etc., can effectively generate foam, has good heat stability, can improve the foaming performance and burning resistance of the foam fire extinguishing agent, and as a wetting agent, can reduce the surface tension of the aqueous solution and wet low-energy surfaces.

[0070] In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.

Claims

1. A quaternary ammonium surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain, characterized in that: The structural formula of the surfactant is:

2. A method for preparing a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain as claimed in claim 1, characterized in that: Specifically: Add N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide, 3-chloropropylmethyldimethoxysilane, potassium iodide and a solvent to a reaction vessel, heat and stir until the raw materials are completely dissolved, then continue to heat and react, and after the reaction is completed, remove the solvent by distillation under reduced pressure, wash with ethanol until the washing liquid does not change color, and obtain a quaternary ammonium surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain.

3. The preparation method of the quaternary ammonium salt surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain according to claim 2, wherein: The molar ratio of N-((dimethylamino)methyl)-4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)hexanamide:3-chloropropylmethyldimethoxysilane:potassium iodide is 1:(1.0-2.0):(0.01-0.03).

4. The preparation method of the quaternary ammonium salt surfactant with a fluorocarbon-silicon-carbon double hydrophobic chain according to claim 2, wherein: The solvent is one of acetonitrile, toluene, benzene, cyclohexane, chloroform, acetone, N,N-dimethylacetamide or N,N-dimethylformamide.

5. The preparation method of the quaternary ammonium salt surfactant with fluorocarbon-silicon-carbon double hydrophobic chains according to claim 2, wherein: The temperature of the heating and stirring is 30-50°C.

6. The method for preparing a quaternary ammonium salt surfactant having a fluorocarbon-silicon-carbon double hydrophobic chain according to claim 2, wherein: The temperature of the temperature-raising reaction is 60-90°C.

7. The preparation method of the quaternary ammonium salt surfactant with fluorocarbon-silicon-carbon double hydrophobic chains according to claim 2, wherein: The temperature-raising reaction time is 4-8 hours.

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