Ultra-long-chain polyoxyethylene ether surfactant capable of being dissolved at subzero temperature and preparation method of ultra-long-chain polyoxyethylene ether surfactant

Abstract

The invention discloses a super-long-chain polyoxyethylene ether surfactant soluble at a temperature below zero and a preparation method of the super-long-chain polyoxyethylene ether surfactant. The chemical formula of the super-long-chain polyoxyethylene ether surfactant dissolved at the temperature below zero is UnCL-350, the structural formula is as follows: # imgabs0 #, U is carbon-carbon double bonds 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 hydrophilic head-based polyoxyethylene ether. According to the invention, 1, 2-propylene glycol is introduced into water to reduce the freezing point of water and create a low-temperature environment below zero, the number of carbon atoms in hydrophobic tail groups of the nonionic surfactant and the number of unsaturation degrees of the hydrophobic tail groups are regulated and controlled, and the purpose of dissolving the nonionic surfactant at the temperature below zero is achieved. According to the invention, the problem that the ultra-long-chain surfactant is not easy to dissolve at the temperature below zero so that the application at low temperature cannot be met is solved, the surfactant dissolved at the temperature below zero is obtained, and the application at low temperature is met.

Description

Technical Field

[0001] The invention belongs to the technical field of surfactants, and in particular relates to an ultra-long-chain polyoxyethylene ether surfactant capable of dissolving at sub-zero temperatures and a preparation method thereof. Background Art

[0002] Ultra-long chain surfactants refer to surfactants with 18 or more carbon atoms in the hydrophobic tail chain. Due to the presence of ultra-long chains, they have strong hydrophobicity and can form single-component worm-like micelles at low concentrations on a microscopic level, showing excellent viscosity-increasing ability. On a macroscopic level, they behave as water-based viscoelastic fluids and are used in personal care, fluid drag reduction, hydraulic fracturing in oil and gas production, self-steering acidification and other fields. However, as the number of carbon atoms in the hydrophobic tail chain increases, the solubility of the surfactant deteriorates, making it unable to dissolve at low temperatures or even sub-zero temperatures, limiting its application at low temperatures, for example, as an aircraft de-icing and anti-icing thickener.

[0003] The property of nonionic surfactants to dissolve below the cloud point is expected to make ultra-long chain nonionic surfactants still have good solubility at low temperatures. According to the different hydrophilic head groups, nonionic surfactants can be divided into polyoxyethylene ether and polyol types. Polyoxyethylene ether surfactants have good water solubility and biocompatibility, so they are widely used in the food and biological industries. However, after the introduction of ultra-long hydrophobic tail chains into such surfactants, their solubility is expected to be reduced, so it is necessary to "tailor" the molecular structure and introduce functional groups that can improve water solubility on the hydrophilic head group and hydrophobic tail chain. Summary of the invention

[0004] The purpose of the present invention is to provide a super-long chain polyoxyethylene ether surfactant soluble at sub-zero temperatures and a preparation method thereof, in order to obtain a surfactant soluble at sub-zero temperatures to meet the application requirements at low temperatures, in order to address the problem that current super-long chain surfactants are not easy to dissolve at sub-zero temperatures and therefore cannot meet the application requirements at low temperatures.

[0005] The present invention mainly introduces 1,2-propylene glycol to lower the freezing point of water to create a sub-zero low temperature environment, and regulates the number of carbon atoms and the unsaturation of the hydrophobic tail group of the non-ionic surfactant to achieve the purpose of dissolving the non-ionic surfactant at sub-zero temperature.

[0006] The ultra-long chain polyoxyethylene ether surfactant soluble at sub-zero temperature provided by the present invention has a chemical formula of U n C L -350, the structural formula is as follows,

[0007]

[0008] Among them, 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, and 350 is the molecular weight of the hydrophilic head group polyoxyethylene ether.

[0009] The present invention provides a method for preparing a super-long chain polyoxyethylene ether surfactant that dissolves at sub-zero temperatures, and the chemical reaction equation and preparation process are as follows:

[0010]

[0011] (1) A certain mass of molecular weight is 350 g·mol -1 Add the polyoxyethylene monomethyl ether MPEG-350 to the dichloromethane solution and stir until the compound is dissolved.

[0012] (2) Weigh a certain amount of catalyst 4-dimethylaminopyridine and dimethylaminopyridine toluenesulfonate, add them to the reaction solution obtained in step (1), and stir until the catalyst is completely dissolved.

[0013] (3) Then add a certain amount of very long chain fatty acids U n C L FA, stirring to dissolve.

[0014] (4) Continue to add a certain amount of condensation agent N,N'-dicyclohexylcarboximide, stir evenly, and carry out esterification reaction at a certain temperature. After a certain period of time, the reaction stops.

[0015] (5) removing the solvent and the condensing agent to obtain a crude product.

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

[0017] In the above technical solution of the present invention, further, the U n C L The number of carbon atoms L on the hydrophobic tail chain of FA is either 20 or 22;

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

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

[0020] In the above technical solution of the present invention, 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 invention, further, in step (3), the very long chain fatty acid U n C L The amount of FA is based on MPEG-350 and U n C L FA was added at a molar ratio of 1:(1.15-1.2).

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

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

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

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

[0026] The present invention adjusts the sub-zero temperature solubility of the surfactant by adjusting the number of carbon atoms L and the number n of C=C on the hydrophobic tail chain, so that the obtained ultra-long chain polyoxyethylene ether surfactant has the characteristic of dissolving at sub-zero temperatures, thereby improving the application range of the ultra-long chain polyoxyethylene ether surfactant at sub-zero temperatures, such as being used as a preservative or thickener in antifreeze or de-icing fluid, or being applied in the field of low-temperature cleaning and care. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the surfactant U1C in Example 1 20 -350 H NMR spectrum and its corresponding structural formula.

[0028] Figure 2 1wt.% of U1C in Example 1 20 -350 transmittance-temperature graph in water / 1,2-propylene glycol.

[0029] Figure 3 is the surfactant U3C in Example 2 22-350 H NMR spectrum and its corresponding structural formula.

[0030] Figure 4 1wt.% of U3C in Example 2 22 -350 transmittance-temperature graph in water / 1,2-propylene glycol.

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

[0032] Figure 6 1wt.% U2C in Example 3 22 -350 transmittance-temperature graph in water / 1,2-propylene glycol.

[0033] Figure 7 1wt.% U1C in Comparative Example 1 24 -350 transmittance-temperature graph in water / 1,2-propylene glycol.

[0034] Figure 8 It is 1wt.% of U1C in Comparative Example 2 22 -350 transmittance-temperature graph in water / 1,2-propylene glycol.

[0035] Fig. 9 1wt.% U1C in Comparative Example 3 22 -750 transmittance-temperature relationship in water / 1,2-propylene glycol. DETAILED DESCRIPTION

[0036] The following examples are used to further describe the specific implementation of the present invention. The following examples are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0037] Example 1

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

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

[0040] (3) Then, 2.66 g 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 FA, stirring to dissolve.

[0041] (4) Add 2.94 g of condensation agent N,N'-dicyclohexylcarboximide to the above solution and continue stirring for 48 hours before stopping the reaction.

[0042] (5) After the reaction is completed, the product is evaporated and then filtered out with 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 finally vacuum dried to obtain cis-11-eicosenoic acid polyoxyethylene monomethyl ether ester U1C 20 -350. The structural formula is

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

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

[0046] The change of transmittance of the surfactant solution with temperature was tested by UV-visible spectrophotometer (Mapada UV-6100). 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 is soluble at sub-zero temperatures.

[0047] Example 2

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

[0049] (2) Weigh 0.11 g of catalyst 4-dimethylaminopyridine and 0.26 g of dimethylaminopyridine toluenesulfonate, add them to the above reaction solution, and stir until the catalyst is completely dissolved.

[0050] (3) Then, 1.79 g 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 FA, stirring to dissolve.

[0051] (4) Add 1.84 g of condensation agent N,N'-dicyclohexylcarboximide to the above solution and continue stirring for 48 hours before stopping the reaction.

[0052] (5) After the reaction is completed, the product is evaporated and then filtered out with a solvent filter to remove the condensing agent to obtain a crude product.

[0053] (6) The crude product was separated and purified by column chromatography, and finally vacuum dried 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 was analyzed by hydrogen nuclear magnetic resonance spectroscopy, and the results are shown in Figure 3 The peak position and peak area of ​​H NMR spectrum are similar to those of U3C 22 The structure of -350 was consistent, indicating that the surfactant was successfully prepared.

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

[0056] The change of transmittance of the surfactant solution with temperature was tested by UV-visible spectrophotometer (Mapada UV-6100). 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 is soluble at sub-zero temperatures.

[0057] Example 3

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

[0059] (2) Weigh 0.11 g of catalyst 4-dimethylaminopyridine and 0.26 g of dimethylaminopyridine toluenesulfonate, add them to the above reaction solution, and stir until the catalyst is completely dissolved.

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

[0061] (4) Add 1.84 g of condensation agent N,N'-dicyclohexylcarboximide to the above solution and continue stirring for 48 hours before stopping the reaction.

[0062] (5) After the reaction is completed, the product is evaporated and then filtered out with a solvent filter to remove the condensing agent to obtain a crude product.

[0063] (6) The crude product was 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 ​​H NMR spectrum are similar to those of U2C 22 The structure of -350 was consistent, indicating that the surfactant was successfully prepared.

[0065] 0.20 g of the above surfactant was placed in 19.80 g of 1,2-propylene glycol / water (50 / 50, vol / vol), and stirred at 60° C. until completely dissolved to prepare a 1 wt. % surfactant solution.

[0066] The change of transmittance of the surfactant solution with temperature was tested by UV-visible spectrophotometer (Mapada UV-6100). The results are shown in Figure 6 It can be found that the transmittance of the surfactant solution at -20°C is close to 100%, indicating that the surfactant is soluble at sub-zero temperatures.

[0067] Comparative Example 1

[0068] In this comparative example, the surfactant U1C 24 -350 was homemade. The preparation method is as follows: JX Wang, J. Wang, B. Wang, S. Guo, YM Feng, Synthesis and aqueous solution properties of polyoxyethylene surfactants with ultra-long unsaturated hydrophobic chains, J. Dispersion Sci. Technol. 34 (2013) 504-510.

[0069] 0.20 g of the above surfactant was placed in 19.80 g of 1,2-propylene glycol / water (50 / 50, vol / vol), and stirred at 60° C. until completely dissolved to prepare a 1 wt. % surfactant solution.

[0070] The change of transmittance of the surfactant solution with temperature was tested by UV-visible spectrophotometer (Mapada UV-6100). The results are shown in Figure 7 It can be found that when the temperature is less than 5°C, the transmittance of the surfactant is close to 0, indicating that the surfactant cannot be dissolved at sub-zero temperatures.

[0071] Comparative Example 2

[0072] In this comparative example, the surfactant U1C 22 -350 is homemade. The preparation method is shown in JX Wang, J. Wang, B. Wang, S. Guo, YM Feng, Synthesis and aqueous solution properties of polyoxyethylene surfactants with ultra-long unsaturated hydrophobic chains, J. Dispersion Sci. Technol. 34 (2013) 504-510.

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

[0074] The change of transmittance of the surfactant solution with temperature was tested by UV-visible spectrophotometer (Mapada UV-6100). The results are shown in Figure 8 It can be found that when the temperature is less than -2°C, the permeability of the surfactant is close to 0, indicating that the surfactant is insoluble below -2°C.

[0075] Comparative Example 3

[0076] In this comparative example, the surfactant U1C 22 -750 is homemade. The preparation method is shown in JX Wang, YM Zhang, ZLChu, YJ Feng, Wormlike micelles formed by ultra-long-chain nonionicsurfactant, Colloid Polym. Sci. 299 (2021) 1295-1304.

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

[0078] The change of transmittance of the surfactant solution with temperature was tested by UV-visible spectrophotometer (Mapada UV-6100). The results are shown in Fig. 9 It can be found that when the temperature is less than 0°C, the transmittance of the surfactant is close to 0, indicating that the surfactant is insoluble at sub-zero temperatures.

Claims

1. A super long chain polyoxyethylene ether surfactant that dissolves at sub-zero temperatures, characterized in that: Its chemical formula is U n C L -350, the structural formula is as follows, Among them, 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, and 350 is the molecular weight of the hydrophilic head group polyoxyethylene ether.

2. The method for preparing the sub-zero temperature soluble ultra-long chain polyoxyethylene ether surfactant according to claim 1, characterized in that: The following steps are involved: (1) The molecular weight is 350 g·mol -1 Polyoxyethylene monomethyl ether MPEG-350 was added to the dichloromethane solution and stirred until the compound was dissolved; (2) adding catalysts 4-dimethylaminopyridine and dimethylaminopyridine toluenesulfonate to the reaction solution obtained in step (1), respectively, and stirring until the catalysts are completely dissolved; (3) Then add the very long chain fatty acid U n C L FA, stir to dissolve; (4) continue to add the condensation agent N,N'-dicyclohexylcarboximide, stir evenly, and carry out esterification reaction at 25°C; (5) removing the solvent and the condensing agent after the reaction is completed to obtain a crude product; (6) The obtained crude product was separated and purified by column chromatography, and finally vacuum dried to obtain surfactant U n C L -350.

3. The method according to claim 2, characterized in that: The U n C L The number L of carbon atoms in the hydrophobic tail chain of FA is 20 or 22.

4. The method according to claim 2, characterized in that: The U n C L The number n of carbon-carbon double bonds C=C on the FA hydrophobic tail chain is any one of 1, 2, and 3.

5. 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.

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

1.

7. The method according to claim 2, characterized in that: Step (3) Very long chain fatty acid U n C L The amount of FA is based on MPEG-350 and U n C L FA was added at a molar ratio of 1:(1.15-1.2).

8. The method according to claim 2, characterized in that: In step (4), the condensing agent N,N'-dicyclohexylcarboximide is added in an amount according to a molar ratio of N,N'-dicyclohexylcarboximide to MPEG-350 of (1-3):

1.

9. The method according to claim 2, characterized in that: The esterification reaction time in step (4) is 36 to 56 hours.

10. Use of the ultra-long chain polyoxyethylene ether surfactant according to claim 1 as a preservative or thickener in antifreeze or de-icing fluid, or in the field of low-temperature cleaning and care.

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