Mild detergent based on compound amino acid surfactant and preparation method thereof

Abstract

The invention relates to the technical field of surfactants, and discloses a mild detergent based on a compound amino acid surfactant and a preparation method of the mild detergent. The preparation method comprises the following steps: reacting glutamic acid with oleoyl serinol, and then reacting with N-acetylcysteine to obtain the compound amino acid surfactant. A side chain of the compound amino acid surfactant contains a hydrophobic alkyl long chain and hydrophilic carboxyl and amino hydrochloride groups, so that the compound amino acid surfactant is amphiphilic and has very strong surface activity, low solution surface tension and good foaming performance. The compound amino acid surfactant contains an amino hydrochloride N + positive ion antibacterial structure and an N-acetylcysteine biological antibacterial structure, and has good sterilization and inhibition performance on escherichia coli and staphylococcus aureus. The compound has good practical application in the aspects of cleaning agents, sterilization disinfectants, degerming dishwashing liquid and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surfactants, in particular to a mild detergent based on a composite amino acid surfactant and a preparation method thereof. BACKGROUND

[0002] The molecular structure of surfactants has amphiphilic properties of hydrophilic and hydrophobic, which can be divided into ionic surfactants, non-ionic surfactants, and amphiphilic surfactants, etc., and has good dispersion, emulsification, foaming, wetting, etc. Performance, can be made into detergents, disinfectants, etc. Widely used in life and health, medical supplies, etc.

[0003] Amino acid surfactants have good biocompatibility, non-toxic and non-irritating characteristics, and are widely used. Patent No. CN116903483B discloses an amino acid surfactant and a preparation method and application thereof. The amino acid surfactant and cleaning preparation prepared by taking 6-(dimethylamino) hexanoic acid or 6-amino hexanoic acid as raw material are suitable for cleaning fabrics, plastic products and the like in indoor decoration. However, the amino acid surfactant of the patent does not have bactericidal performance, which is not conducive to its practical application in bactericidal disinfectants, germ-free detergents, etc. SUMMARY

[0004] The present application solves the problem of poor foaming and antibacterial performance of traditional surfactants.

[0005] The technical scheme of the present application is a preparation method of a composite amino acid surfactant:

[0006] (1) Add methanol, serine alcohol and triethylamine to the reaction container, stir and place in a low-temperature reaction instrument, then drop the tetrahydrofuran solution containing oleoyl chloride, add saturated sodium chloride solution after reaction, extract with dichloromethane, dry the organic phase with anhydrous magnesium sulfate, concentrate under reduced pressure, and then separate the crude product by silica gel column chromatography to obtain oleoyl serine alcohol.

[0007] (2) Add solvent, glutamic acid, oleoyl serine alcohol and p-toluenesulfonic acid to the reaction container, heat and stir to react, remove toluene under reduced pressure, wash the product with ethanol, and dry to obtain a surfactant precursor. The preparation reaction formula is:

[0008] .

[0009] (3) Add N,N-dimethylformamide, surfactant precursor, N-acetyl cysteine and dimethyl anisole (DMPA) to the reaction container, place under a UV lamp, irradiate and stir to react, add water and drop hydrochloric acid, then pour the solution into ethanol, filter the product, wash with ethanol, and dry to obtain a composite amino acid surfactant. The preparation reaction formula is:

[0010] .

[0011] Furthermore, in (1), the ratio of serine alcohol to oleoyl chloride is 1 mol: (1-1.1) mol.

[0012] Furthermore, in (1), the reaction temperature is 15-25℃ and the reaction time is 12-18h.

[0013] Furthermore, in (2), the reaction solvent is toluene or xylene.

[0014] Furthermore, in (2), the ratio of glutamic acid, oleoylserine alcohol, and p-toluenesulfonic acid is 1 mol: (1.2-1.6) mol: (0.3-0.4) mol.

[0015] Furthermore, in (2), the reaction temperature is 110-140℃ and the reaction time is 7-12h.

[0016] Furthermore, in (3), the ratio of surfactant precursor, N-acetylcysteine, and benzoin dimethyl ether is 100g:(12-40)g:(0.2-0.8)g.

[0017] Furthermore, in (3), the main wavelength of the ultraviolet lamp is 365nm and the power is 40-80W.

[0018] Furthermore, the reaction time in (3) is 1-2 hours.

[0019] Furthermore, in (3), hydrochloric acid is added dropwise to adjust the pH of the solution to 4-5.

[0020] Furthermore, mild detergents based on compound amino acid surfactants are available, with the concentration of the compound amino acid surfactant in the mild detergent being 5-30 g / L.

[0021] The beneficial technical effects of this invention are as follows: Glutamic acid and oleoylserine are subjected to esterification polymerization, and then the alkenyl group is added to the thiol group of N-acetylcysteine ​​to obtain a composite amino acid surfactant. Its main chain is a biodegradable polyester structure containing biocompatible glutamic acid, cysteine ​​and other structures, which is green, environmentally friendly and pollution-free, mild and non-irritating. At the same time, the side chain contains hydrophobic alkyl long chains and hydrophilic carboxyl and amino hydrochloride groups, thus exhibiting amphiphilicity, strong surface activity, low solution surface tension and good foaming performance.

[0022] The composite amino acid surfactant of the present invention contains amino hydrochloride N +The positive ion antibacterial structure and the N-acetylcysteine ​​bioantibacterial structure exhibit excellent bactericidal and inhibitory properties against Escherichia coli and Staphylococcus aureus. It has promising practical applications in cleaning agents, disinfectants, and antibacterial detergents. Detailed Implementation

[0023] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0024] Example 1 (1) Add 40 mL of methanol, 6 mmol of serine (CAS No. 534-03-2), and 1 mL of triethylamine to a reaction vessel. After stirring, place the vessel in a low-temperature reaction apparatus. Add 50 mL of tetrahydrofuran solution containing 6.6 mmol of oleoyl chloride (CAS No. 112-77-6) dropwise at -20 °C. Then, stir the reaction at 25 °C for 12 h. Add saturated sodium chloride solution, extract with dichloromethane, dry the organic phase with anhydrous magnesium sulfate to remove water, concentrate under reduced pressure, and separate the crude product by silica gel column chromatography. Elute with ethyl acetate and methanol solution to obtain oleoyl serine. The structural formula is: .

[0025] (2) Add 40 mL xylene, 10 mmol glutamic acid (CAS No. 617-65-2), 14 mmol oleoylserine alcohol and 3.6 mmol p-toluenesulfonic acid to the reaction vessel, heat to 140 °C, stir and reflux for 7 h, concentrate under reduced pressure to remove toluene, wash the product with ethanol, dry and obtain surfactant precursor.

[0026] (3) Add 60 mL of N,N-dimethylformamide, 5 g of surfactant precursor, 0.6 g of N-acetylcysteine ​​(CAS No. 616-91-1), and 10 mg of benzoin dimethyl ether to the reaction vessel. Place it under a 60 W ultraviolet lamp (main wavelength 365 nm) for irradiation and stirring for 1 h. Add 400 mL of water and dropwise add 20% hydrochloric acid to adjust the pH of the solution to 5. Then pour the solution into ethanol, filter it, wash the product with ethanol, and dry it to obtain the composite amino acid surfactant.

[0027] Example 2 (1) Add 40 mL of methanol, 6 mmol of serine and 1 mL of triethylamine to the reaction vessel, stir and place in a low temperature reaction apparatus. Add 50 mL of tetrahydrofuran solution containing 6 mmol of oleoyl chloride at -15 °C. Then stir the reaction at 15 °C for 18 h. Add saturated sodium chloride solution and extract with dichloromethane. Dry the organic phase with anhydrous magnesium sulfate to remove water. After concentration under reduced pressure, separate the crude product by silica gel column chromatography and elute with ethyl acetate and methanol solution to obtain oleoyl serine.

[0028] (2) Add 50 mL of toluene, 10 mmol of glutamic acid, 12 mmol of oleoylserine alcohol and 4 mmol of p-toluenesulfonic acid to the reaction vessel, heat to 110 °C, stir and reflux for 12 h, concentrate under reduced pressure to remove toluene, wash the product with ethanol, dry and obtain the surfactant precursor.

[0029] (3) Add 70 mL of N,N-dimethylformamide, 5 g of surfactant precursor, 1 g of N-acetylcysteine ​​and 20 mg of benzoin dimethyl ether to the reaction vessel, place it under an 80 W ultraviolet lamp (main wavelength 365 nm), irradiate and stir for 1 h, add 500 mL of water and add 20% hydrochloric acid by mass to adjust the pH of the solution to 4, then pour the solution into ethanol, filter and wash the product with ethanol, dry it to obtain the composite amino acid surfactant.

[0030] Example 3 (1) Add 50 mL xylene, 10 mmol glutamic acid, 16 mmol oleoylserine alcohol (prepared from Example 1) and 3 mmol p-toluenesulfonic acid to the reaction vessel, heat to 130 °C, stir and reflux for 9 h, concentrate under reduced pressure to remove toluene, wash the product with ethanol, dry, and obtain the surfactant precursor.

[0031] (2) Add 80 mL of N,N-dimethylformamide, 5 g of surfactant precursor, 1.5 g of N-acetylcysteine ​​and 32 mg of benzoin dimethyl ether to the reaction vessel, place it under a 40 W ultraviolet lamp (main wavelength 365 nm), irradiate and stir for 2 h, add 500 mL of water and add 30% hydrochloric acid dropwise to adjust the pH of the solution to 4, then pour the solution into ethanol, filter and wash the product with ethanol, dry it to obtain the composite amino acid surfactant.

[0032] Example 4 (1) Add 50 mL xylene, 10 mmol glutamic acid, 12 mmol oleoylserine alcohol (prepared from Example 1) and 3.6 mmol p-toluenesulfonic acid to the reaction vessel, heat to 140 °C, stir and reflux for 8 h, concentrate under reduced pressure to remove toluene, wash the product with ethanol, dry, and obtain the surfactant precursor.

[0033] (2) Add 80 mL of N,N-dimethylformamide, 5 g of surfactant precursor, 2 g of N-acetylcysteine ​​and 40 mg of benzoin dimethyl ether to the reaction vessel, place it under an 80 W ultraviolet lamp (main wavelength 365 nm), irradiate and stir for 1 h, add 500 mL of water and add 30% hydrochloric acid by mass to adjust the pH of the solution to 4, then pour the solution into ethanol, filter and wash the product with ethanol, dry it to obtain the composite amino acid surfactant.

[0034] Comparative Example 1 used the surfactant precursor prepared in Example 1 as the surfactant.

[0035] Comparative Example 2 (1) Add 40 mL xylene, 10 mmol glutaric acid, 14 mmol oleoylserine alcohol and 3.6 mmol p-toluenesulfonic acid to the reaction vessel, heat to 140 °C, stir and reflux for 7 h, concentrate under reduced pressure to remove toluene, wash the product with ethanol, dry and obtain surfactant precursor.

[0036] (2) Add 60 mL of N,N-dimethylformamide, 5 g of surfactant precursor, 0.6 g of N-acetylcysteine ​​and 10 mg of benzoin dimethyl ether to the reaction vessel, place it under a 60 W ultraviolet lamp (main wavelength 365 nm), irradiate and stir for 1 h, add 400 mL of water and add 20% hydrochloric acid by mass to adjust the pH of the solution to 5, then pour the solution into ethanol, filter and wash the product with ethanol, dry and obtain the surfactant.

[0037] Comparative Example 3 (1) Add 40 mL of methanol, 6 mmol of serine, and 1.46 mL of triethylamine to a reaction vessel. After stirring, place the mixture in a low-temperature reaction apparatus. Add 50 mL of tetrahydrofuran solution containing 6.6 mmol of octadecyl chloride at -20 °C. Then, stir the reaction at 25 °C for 12 h. Add saturated sodium chloride solution and extract with dichloromethane. Dry the organic phase with anhydrous magnesium sulfate to remove water. After concentration under reduced pressure, separate the crude product by silica gel column chromatography and elute with ethyl acetate and methanol solution to obtain octadecyl serine. The structural formula is: .

[0038] (2) Add 40 mL xylene, 10 mmol glutamic acid, 14 mmol octadecyl serine alcohol and 3.6 mmol p-toluenesulfonic acid to the reaction vessel, heat to 140 °C, stir and reflux for 7 h, concentrate under reduced pressure to remove toluene, wash the product with ethanol, dry and obtain surfactant precursor.

[0039] (3) Add 60 mL of N,N-dimethylformamide, 5 g of surfactant precursor, 0.6 g of N-acetylcysteine ​​and 10 mg of benzoin dimethyl ether to the reaction vessel, place it under a 60 W ultraviolet lamp (main wavelength 365 nm) for irradiation and stirring for 1 h, add 400 mL of water and add 20% hydrochloric acid by mass to adjust the pH of the solution to 5, then pour the solution into ethanol, filter and wash the product with ethanol, dry it to obtain the surfactant.

[0040] The surfactant was added to deionized water and stirred to prepare an aqueous solution with a concentration of 5 g / L. The solubility of the solution was observed, and the surface tension of the solution was tested using a surface tension meter at a temperature of 25°C.

[0041] Pour the surfactant aqueous solution into the foam evaluation instrument, set the stirring speed to 2000 r / min, stir for 1 min, and observe the foam height.

[0042] Activated Staphylococcus aureus and Escherichia coli suspensions (concentration of 10) were respectively prepared. 6 (cfu / mL) was inoculated onto agar medium, and filter paper with a diameter of 6 mm was sterilized by ultraviolet light; then it was soaked in an aqueous surfactant solution, and after being taken out, the filter paper was attached to the surface of the agar medium and placed in a constant temperature incubator at 37℃ for 24 h. The diameter of the inhibition zone was measured. Each group of samples was tested 3 times and the average value was taken.

[0043] Table 1 Properties of the surfactant

[0044] After testing, the aqueous solutions of the surfactants prepared in Examples 1-4 were found to be transparent, free of precipitation, and exhibited low surface tension, high surface activity, large foaming height, and good foaming performance. They also demonstrated high inhibition zone diameters against *Escherichia coli* and *Staphylococcus aureus*, exhibiting excellent antibacterial properties. This is primarily because the surfactant's main chain is a hydrophobic polyester structure, with hydrophobic alkyl long chains in the side chains, and simultaneously containing hydrophilic carboxyl and amino hydrochloride groups, exhibiting amphiphilicity and strong surface activity. The resulting low surface tension and good foaming performance, along with the presence of amino hydrochloride N... + The positive ion antibacterial structure and the N-acetylcysteine ​​bioantibacterial structure exhibit good bactericidal and inhibitory properties against Escherichia coli and Staphylococcus aureus.

[0045] Comparative Example 1's surfactant precursor lacks the hydrophilic structures of carboxyl groups and amino hydrochloride, exhibiting very poor water solubility. Its aqueous solution contains a large amount of precipitate, exhibits high surface tension, low foaming height, and poor surface activity and foaming performance. Furthermore, it does not contain amino hydrochloride N. + The positive ion antibacterial structure and the N-acetylcysteine ​​bioantibacterial structure have very poor antibacterial properties.

[0046] Comparative Example 2: glutaric acid and the surfactant prepared from it do not contain amino hydrochloride structures, have poor water solubility, high surface tension of the solution, low foaming height, poor surface activity and foaming performance, and poor antibacterial properties.

[0047] The octadecylserine alcohol of Comparative Example 3 and the surfactant precursor prepared therefrom do not contain alkenyl groups and cannot undergo addition reaction with the thiol group of N-acetylcysteine. The prepared surfactant does not contain the N-acetylcysteine ​​structure, has poor water solubility, high surface tension of the solution, low foaming height, poor surface activity and foaming performance, and poor antibacterial properties.

[0048] The surfactant (prepared in Example 4) was added to deionized water and stirred to prepare an aqueous solution with a concentration of 5-30 g / L. The solubility of the solution was observed, and the surface tension, foam height and antibacterial properties of the solution were tested.

[0049] Table 2 Performance of surfactants at different concentrations

[0050] As shown in Table 2, solutions of surfactants at different concentrations all exhibited low surface tension, high foaming height, and good antibacterial properties.

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a composite amino acid surfactant, characterized in that, The preparation method includes: (1) Add solvent, glutamic acid, oleoylserine alcohol and p-toluenesulfonic acid to the reaction vessel, heat and stir to carry out the reaction, concentrate under reduced pressure to remove toluene, wash the product, dry and obtain surfactant precursor. (2) Add N,N-dimethylformamide, surfactant precursor, N-acetylcysteine ​​and benzoin dimethyl ether to the reaction vessel, place it under ultraviolet light, irradiate and stir the reaction, add water and add hydrochloric acid dropwise, then pour the solution into ethanol, filter and wash the product, dry it to obtain the composite amino acid surfactant.

2. The method for preparing the composite amino acid surfactant according to claim 1, characterized in that, The reaction solvent in (1) is toluene or xylene.

3. The method for preparing the composite amino acid surfactant according to claim 1, characterized in that, The ratio of glutamic acid, oleoylserine alcohol, and p-toluenesulfonic acid in (1) is 1 mol: (1.2-1.6) mol: (0.3-0.4) mol.

4. The method for preparing the composite amino acid surfactant according to claim 1, characterized in that, The reaction temperature in (1) is 110-140℃ and the reaction time is 7-12h.

5. The method for preparing the composite amino acid surfactant according to claim 1, characterized in that, The ratio of surfactant precursor, N-acetylcysteine, and benzoin dimethyl ether in (2) is 100g:(12-40)g:(0.2-0.8)g.

6. The method for preparing the composite amino acid surfactant according to claim 1, characterized in that, The main wavelength of the ultraviolet lamp in (2) is 365nm, the power is 40-80W, and the reaction time is 1-2h.

7. The method for preparing the composite amino acid surfactant according to claim 1, characterized in that, In step (2), hydrochloric acid is added dropwise to adjust the pH of the solution to 4-5.

8. The method for preparing the composite amino acid surfactant according to claim 1, characterized in that, The preparation method of the oleoylserine alcohol includes: adding methanol, serine alcohol and triethylamine to a reaction vessel, stirring and placing it in a low-temperature reaction instrument, adding a tetrahydrofuran solution containing oleoyl chloride dropwise, controlling the ratio of serine alcohol to oleoyl chloride to be 1 mol: (1-1.1) mol, and then stirring the reaction at 15-25℃ for 12-18 h, followed by extraction and column chromatography separation to obtain oleoylserine alcohol.

9. A composite amino acid surfactant obtained by the preparation method according to any one of claims 1-8.

10. A mild detergent based on the composite amino acid surfactant of claim 9, characterized in that, The concentration of the compound amino acid surfactant in the mild detergent is 5-30 g / L.

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