Ultra-long chain polyoxyethylene ether surfactants dissolved at subzero temperatures and methods of making the same

Abstract

The application discloses a super-long chain polyoxyethylene ether surfactant soluble at subzero temperature and a preparation method thereof. The chemical formula of the super-long chain polyoxyethylene ether surfactant soluble at subzero temperature is U n C L -350, a structural formula is as follows, wherein U is a carbon-carbon double bond in a hydrophobic tail chain, n is the number of double bonds in the hydrophobic tail chain, C is a carbon atom in the hydrophobic tail chain, L is the number of carbon atoms in the hydrophobic tail chain, and 350 is the molecular weight of a hydrophilic head group polyoxyethylene ether. The application creates a subzero low-temperature environment by introducing 1,2-propanediol into water to reduce the freezing point of water, and regulates the number of carbon atoms in a hydrophobic tail group of a non-ionic surfactant and the number of unsaturation degrees of the hydrophobic tail group, so that the non-ionic surfactant is soluble at subzero temperature. The application solves the problem that the super-long chain surfactant is not easy to be soluble at subzero temperature, and thus cannot meet the application at low temperature. The surfactant soluble at subzero temperature is obtained, and the application at low temperature is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of surfactants, and particularly relates to a super-long-chain polyoxyethylene ether surfactant capable of being dissolved at subzero temperature and a preparation method thereof. BACKGROUND

[0002] The super-long-chain surfactant refers to a surfactant with a hydrophobic tail chain of 18 or more carbon atoms. Due to the existence of the super-long chain, the surfactant has strong hydrophobicity, can form single-component worm-like micelles at a low concentration in a microcosmic view, and shows excellent tackifying capacity in a macroscopic view. The surfactant is a water-based viscoelastic fluid and is used in the fields of personal care, fluid drag reduction, hydraulic fracturing of oil and gas exploitation, self-diverting acidification and the like. However, with the increase of the number of carbon atoms in the hydrophobic tail chain, the solubility of the surfactant becomes poor, so that the surfactant cannot be dissolved at low temperature or even subzero temperature, which limits the application of the surfactant at low temperature, for example, the application of the surfactant as an aircraft deicing and anti-icing thickening agent.

[0003] The solubility of the nonionic surfactant below the cloud point is expected to make the super-long-chain nonionic surfactant have good solubility at low temperature. According to the difference of the hydrophilic head group, the nonionic surfactant can be divided into polyoxyethylene ether and polyhydric alcohol type. The polyoxyethylene ether surfactant has good water solubility and biocompatibility, and is widely used in the food and biological industries. However, after the super-long hydrophobic tail chain is introduced into the surfactant, the solubility of the surfactant is expected to be reduced, so it is necessary to “tailor” the molecular structure and introduce a functional group capable of improving water solubility into the hydrophilic head group and the hydrophobic tail chain. SUMMARY

[0004] The application aims to solve the problem that the current super-long-chain surfactant cannot be dissolved at subzero temperature and cannot meet the application at low temperature, and provides a super-long-chain polyoxyethylene ether surfactant capable of being dissolved at subzero temperature and a preparation method thereof, so as to obtain a surfactant capable of being dissolved at subzero temperature and meet the application at low temperature.

[0005] The application mainly creates a subzero low-temperature environment by introducing 1,2-propanediol to reduce the freezing point of water, regulates the number of carbon atoms in the hydrophobic tail group of the nonionic surfactant and the unsaturation of the hydrophobic tail group, so as to achieve the purpose of dissolving the nonionic surfactant at subzero temperature.

[0006] The super-long-chain polyoxyethylene ether surfactant provided by the application has the chemical formula U n C L -350, and the structural formula is as follows,

[0007]

[0008] Wherein, U is the carbon-carbon double bond in the hydrophobic tail chain, n is the number of double bonds in the hydrophobic tail chain, C is the carbon atom in the hydrophobic tail chain, L is the number of carbon atoms in the hydrophobic tail chain, 350 is the molecular weight of the hydrophilic head polyoxyethylene ether.

[0009] The application provides a preparation method of the super-long chain polyoxyethylene ether surfactant dissolved at subzero temperature, a chemical reaction equation and a preparation process.

[0010]

[0011] (1) A certain mass of polyoxyethylene monomethyl ether MPEG-350 with a molecular weight of 350 g·mol-1 is added to a dichloromethane solution, and stirring is performed until the compound is dissolved. -1

[0012] (2) A certain amount of catalyst 4-dimethylaminopyridine and dimethylaminopyridine toluenesulfonate is weighed and added to the reaction solution obtained in step (1), and stirring is performed until the catalyst is completely dissolved.

[0013] (3) Then, a certain amount of super-long chain fatty acid U n C L FA is added, and stirring is performed to dissolve the super-long chain fatty acid.

[0014] (4) A certain amount of condensing agent N,N'-dicyclohexyl carbodiimide is continuously added, stirring is uniformly performed, esterification is performed at a certain temperature, and the reaction is stopped after a certain time.

[0015] (5) The solvent and the condensing agent are removed, and a crude product is obtained.

[0016] (6) The crude product is separated and purified by column chromatography, and finally vacuum drying is performed to obtain the surfactant U n C L -350.

[0017] In the above technical solution of the application, further, the number L of carbon atoms in the hydrophobic tail chain of the U n C L FA is any one of 20 and 22;

[0018] In the above technical solution of the application, further, the number n of carbon-carbon double bonds C=C in the hydrophobic tail chain of the U n C L FA is any one of 1, 2 and 3.

[0019] In the above technical solution of the application, further, the mass of the MPEG-350 in step (1) is 1-5% of the mass of the dichloromethane, and preferably 2%.

[0020] ​In the above technical solution of the present application, further, the molar ratio of the catalyst 4-dimethylaminopyridine and dimethylaminopyridine toluenesulfonate to MPEG-350 is (0.1-0.5):1, preferably 0.2:1.

[0021] In the above technical solution of the present application, further, the dosage of the step (3) super-long chain fatty acid U n C L The dosage of the FA is added according to the molar ratio of MPEG-350 to U n C L FA is 1:(1.15-1.2).

[0022] In the above technical solution of the present application, further, the dosage of the step (4) condensing agent N,N'-dicyclohexylcarbodiimide is added according to the molar ratio of N,N'-dicyclohexylcarbodiimide to MPEG-350, which is (1-3):1, preferably 2:1.

[0023] In the above technical solution of the present application, further, the reaction temperature of the step (4) is 10-30℃, preferably 25℃, and the esterification reaction time is 36-56h, preferably 48h.

[0024] The super-long chain polyoxyethylene ether surfactant prepared by the above method provided by the present application can be dissolved in the range of -20-80℃, and the dissolution temperature can be adjusted according to actual needs.

[0025] Compared with the prior art, the present application has the following beneficial effects and characteristics:

[0026] The present application adjusts the number of carbon atoms L and the number of C=C on the hydrophobic tail chain, adjusts the subzero temperature dissolution performance of the surfactant, so that the obtained super-long chain polyoxyethylene ether surfactant has the characteristics of subzero temperature dissolution, thereby improving the application range of the super-long chain polyoxyethylene ether surfactant at subzero temperature, such as being used as a preservative or thickening agent in antifreeze or ice-melting liquid, or being applied in the field of low-temperature cleaning and care. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of the surfactant U1C 20 -350 in Example 1 and its corresponding structural formula.

[0028] Figure 2 is the permeability-temperature relationship diagram of 1wt.% U1C 20 -350 in Example 1 in water / 1,2-propanediol.

[0029] Figure 3 is the surfactant U3C 22-350 1H NMR spectrum and its corresponding structural formula.

[0030] Figure 4 It is 1 wt.% U3C in Example 2 22 -350 Transmittance in water / 1,2-propanediol as a function of temperature.

[0031] Figure 5 The surfactant U2C in Example 3 22 -350 1H NMR spectrum and its corresponding structural formula.

[0032] Figure 6 It is 1 wt.% U2C in Example 3 22 -350 Transmittance in water / 1,2-propanediol as a function of temperature.

[0033] Figure 7 1 wt.% U1C in Comparative Example 1 24 -350 Transmittance in water / 1,2-propanediol as a function of temperature.

[0034] Figure 8 1 wt.% U1C in Comparative Example 2 22 -350 Transmittance in water / 1,2-propanediol as a function of temperature.

[0035] Figure 9 1 wt.% U1C in Comparative Example 3 22 -750 Transmittance-temperature relationship in water / 1,2-propanediol. Detailed Implementation

[0036] The specific embodiments of the present invention will be further described below with reference to implementation examples. These embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0037] Example 1

[0038] (1) 2.50g of a substance with a molecular weight of 350g·mol -1 MPEG was added to 125g of dichloromethane solution and stirred until the compound dissolved.

[0039] (2) Weigh 0.17g of catalyst 4-dimethylaminopyridine and 0.42g of dimethylaminopyridine toluenesulfonate, add them to the above reaction solution, and stir until the catalyst is completely dissolved.

[0040] (3) Subsequently, 2.66g of ultra-long chain fatty acid U3C with a carbon chain length L of 22 and an unsaturation degree n of 3 was added. 22 Add FA and stir until dissolved.

[0041] (4) After 48 h of continuous stirring, the reaction was stopped.

[0042] (5) After the reaction was completed, the solution was rotary evaporated, and then filtered through a solvent filter to remove the condensing agent, to obtain a crude product.

[0043] (6) The crude product was separated and purified by column chromatography, and then vacuum dried to obtain the surfactant U1C 20 -350. The structural formula is

[0044] The surfactant in this example was analyzed by nuclear magnetic resonance hydrogen spectrum, and the results are shown in Figure 1 . The peak position and peak area of the nuclear magnetic resonance hydrogen spectrum are consistent with the structure of U1C 20 -350, indicating that the surfactant is successfully prepared.

[0045] The surfactant 0.20 g was placed in 19.80 g of 1,2-propanediol / water (50 / 50, vol / vol) and stirred at 60°C until completely dissolved to prepare a 1 wt.% surfactant solution.

[0046] The surfactant solution was tested by ultraviolet-visible spectrophotometer (Mapada UV-6100) to test the change of transmittance with temperature, and the results are shown in Figure 2 . It can be found that the transmittance of the surfactant is close to 100% at -20°C, indicating that the surfactant can be dissolved at subzero temperature.

[0047] Example 2

[0048] (1) 1.56 g of MPEG with a molecular weight of 350 g·mol -1 was added to a 78 g dichloromethane solution and stirred until the compound was dissolved.

[0049] (2) 0.11 g of catalyst 4-dimethylaminopyridine and 0.26 g of dimethylaminopyridine toluenesulfonic acid salt were weighed and added to the above reaction solution, respectively, and stirred until the catalyst was completely dissolved.

[0050] (3) Then, 1.79 g of ultra-long chain fatty acid U3C 22 FA with a carbon chain length L of 22 and an unsaturation n of 3 was added and stirred to dissolve.

[0051] (4) 1.84 g of condensing agent N,N'-dicyclohexyl carbodiimide was added to the above solution. After 48 h of continuous stirring, the reaction was stopped.

[0052] (5) After the reaction is completed, rotary evaporation is performed, and then the condensing agent is filtered out using a solvent filter to obtain a crude product.

[0053] (6) The crude product is separated and purified by column chromatography, and vacuum drying is finally performed to obtain cis-13, 16, 19-docosatrienoic acid polyoxyethylene monomethyl ether ester U3C. 22 -350. The structural formula is

[0054] The surfactant in this example is analyzed by nuclear magnetic resonance hydrogen spectrum, and the results are shown in Figure 3 . The peak position and peak area of the nuclear magnetic resonance hydrogen spectrum are consistent with the structure of U3C 22 -350, indicating that the surfactant is successfully prepared.

[0055] The above surfactant 0.20 g is placed in 19.80 g of 1,2-propanediol / water (50 / 50, vol / vol), and stirred at 60°C until completely dissolved to prepare a 1 wt.% surfactant solution.

[0056] The surfactant solution is tested by ultraviolet visible spectrophotometer (Mapada UV-6100) to test the change of transmittance with temperature, and the results are shown in Figure 4 . It can be found that the transmittance of the surfactant is close to 100% at -20°C, indicating that the surfactant can be dissolved at subzero temperature.

[0057] Example 3

[0058] (1) 1.56 g of MPEG with a molecular weight of 350 g·mol -1 is added to a dichloromethane solution of 78 g, and stirred until the compound is dissolved.

[0059] (2) 0.11 g of catalyst 4-dimethylaminopyridine and 0.26 g of dimethylaminopyridine toluenesulfonate are weighed and added to the above reaction solution, respectively, and stirred until the catalyst is completely dissolved.

[0060] (3) Then, 1.80 g of ultra-long chain fatty acid U2C 22 FA with a carbon chain length L of 22 and an unsaturation n of 2 is added and stirred to dissolve it.

[0061] (4) 1.84 g of condensing agent N,N'-dicyclohexyl carbodiimide is added to the above solution. The reaction is stopped after 48 h of continuous stirring.

[0062] (5) After the reaction is completed, rotary evaporation is performed, and then the condensing agent is filtered out using a solvent filter to obtain a crude product.

[0063] (6) The above crude product is separated and purified by column chromatography, and finally vacuum dried to obtain cis 13, 16-docosadienoic acid polyoxyethylene monomethyl ether ester U2C 22 -350. The structural formula is

[0064] The surfactant in this example was analyzed by nuclear magnetic resonance spectroscopy, and the results are shown in Figure 5 . The peak position and peak area of nuclear magnetic resonance hydrogen spectrum are consistent with the structure of U2C 22 -350, indicating that the surfactant is successfully prepared.

[0065] Take 0.20 g of the above surfactant and place it in 19.80 g of 1,2-propanediol / water (50 / 50, vol / vol), stir at 60°C until completely dissolved, to prepare a 1 wt.% surfactant solution.

[0066] The transmittance of the surfactant solution was tested by ultraviolet visible spectrophotometer (Mapada UV-6100) as the temperature changed, and the results are shown in Figure 6 It can be found that the transmittance of the surfactant solution is close to 100% at -20°C, indicating that the surfactant can be dissolved at subzero temperature.

[0067] Comparative Example 1

[0068] The surfactant U1C 24 -350 in this comparative example is self-made, and the preparation method is described in: J. X. Wang, J. Wang, B. Wang, S. Guo, Y. M. Feng, Synthesis and aqueous solution properties of polyoxyethylene surfactants with ultra-long unsaturated hydrophobic chains, J. Dispersion Sci. Technol. 34 (2013) 504-510.

[0069] Take 0.20 g of the above surfactant and place it in 19.80 g of 1,2-propanediol / water (50 / 50, vol / vol), stir at 60°C until completely dissolved, to prepare a 1 wt.% surfactant solution.

[0070] The transmittance of the surfactant solution was tested by ultraviolet visible spectrophotometer (Mapada UV-6100) as the temperature changed, and the results are shown in Figure 7 It can be found that the transmittance of the surfactant solution is close to 100% at -20°C, indicating that the surfactant can be dissolved at subzero temperature.

[0071] Comparative Example 2

[0072] Surfactant U1C in this comparative example 22 - 350 was self-made, and the preparation method was described in J. X. Wang, J. Wang, B. Wang, S. Guo, Y. M. Feng, Synthesis and aqueous solution properties of polyoxyethylene surfactants with ultra-long unsaturated hydrophobic chains, J. Dispersion Sci. Technol. 34 (2013) 504-510.

[0073] The above surfactant 0.20 g was placed in 19.80 g of 1,2-propanediol / water (50 / 50, vol / vol), stirred at 60°C until completely dissolved, and a 1 wt.% surfactant solution was prepared.

[0074] The change of the transmittance of the surfactant solution with temperature was tested by using a UV-visible spectrophotometer (Mapada UV-6100), and the results are shown in Figure 8 It can be found that when the temperature is < -2°C, the transmittance of the surfactant is close to 0, indicating that the surfactant is not dissolved below -2°C.

[0075] Comparative Example 3

[0076] Surfactant U1C in this comparative example 22 - 750 was self-made, and the preparation method was described in J. X. Wang, Y. M. Zhang, Z. L. Chu, Y. J. Feng, Wormlike micelles formed by ultra-long-chain nonionic surfactant, Colloid Polym. Sci. 299 (2021) 1295-1304.

[0077] The above surfactant 0.20 g was placed in 19.80 g of 1,2-propanediol / water (50 / 50, vol / vol), stirred at 60°C until completely dissolved, and a 1 wt.% surfactant solution was prepared.

[0078] The change of the transmittance of the surfactant solution with temperature was tested by using a UV-visible spectrophotometer (Mapada UV-6100), and the results are shown in Figure 9 It can be found that when the temperature is < -2°C, the transmittance of the surfactant is close to 0, indicating that the surfactant is not dissolved below -2°C.

Claims

1. A super-long-chain polyoxyethylene ether surfactant that dissolves at sub-zero temperatures, characterized in that, Its chemical formula and structural formula are as follows: cis-11-eicosenoic acid polyoxyethylene monomethyl ether ester, chemical formula U1C 20 -350, structural formula is ; cis-13,16,19-docosatrienoic acid polyoxyethylene monomethyl ether, chemical formula U3C 22 -350, structural formula is ; cis-13,16-docosadienoic acid polyoxyethylene monomethyl ether ester U2C 22 -350, structural formula is .

2. The method for preparing the ultra-long-chain polyoxyethylene ether surfactant dissolved at sub-zero temperatures according to claim 1, characterized in that, Includes the following steps: (1) The molecular weight is 350 g·mol −1 Polyoxyethylene monomethyl ether MPEG-350 was added to a dichloromethane solution and stirred until the compound dissolved. (2) Add the catalysts 4-dimethylaminopyridine and dimethylaminopyridine toluenesulfonate to the reaction solution obtained in step (1) and stir until the catalysts are completely dissolved; (3) Then add ultra-long chain fatty acid U n C L FA, stir to dissolve; the U n C L The number of carbon atoms L on the hydrophobic tail chain of FA is either 20 or 22; the U n C L The number n of carbon-carbon double bonds C=C on the hydrophobic tail chain of FA can be any one of 1, 2, or 3; (4) Continue to add condensing agent N,N'-dicyclohexylcarboimide, stir evenly, and carry out esterification reaction at 25°C; (5) After the reaction is complete, remove the solvent and condensing agent to obtain the crude product; (6) The crude product was separated and purified by column chromatography, and finally dried under vacuum to obtain surfactant U. n C L -350.

3. The method according to claim 2, characterized in that, In step (1), the mass of MPEG-350 is 1 to 5% of the mass of dichloromethane.

4. The method according to claim 2, characterized in that, The molar ratio of catalysts 4-dimethylaminopyridine and dimethylaminopyridine toluenesulfonate to MPEG-350 is (0.1~0.5):

1.

5. The method according to claim 2, characterized in that, Step (3) Ultra-long chain fatty acid U n C L FA usage according to MPEG-350 and U n C L The molar ratio of FA is 1:(1.15~1.2) added.

6. The method according to claim 2, characterized in that, Step (4) The amount of condensing agent N,N'-dicyclohexylcarboimide is added according to the molar ratio of N,N'-dicyclohexylcarboimide to MPEG-350 of (1~3):

1.

7. The method according to claim 2, characterized in that, The esterification reaction time in step (4) is 36~56 h.

8. The use of the ultra-long chain polyoxyethylene ether surfactant of claim 1 as a thickener in antifreeze or de-icing fluid.

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