Amino acid surfactant and method for its preparation

Abstract

The application discloses a novel amino acid surfactant and a preparation method thereof. The novel amino acid surfactant has a hydrophobic part formed by a catechol compound and a hydrophilic part formed by an amino acid. The preparation method comprises the following steps: subjecting ortho-benzoquinone obtained by oxidizing the catechol compound to Michael addition reaction and Schiff base reaction with the amino acid, so that the catechol and the amino acid are covalently connected, and the novel amino acid surfactant is obtained. The preparation method has the advantages of short reaction time, simple process and low energy consumption. The prepared surfactant has the advantages of novel structure, high biological safety and excellent surface performance.

Description

Technical Field

[0001] This invention relates to the field of fine chemicals, and particularly to the technical field of amino acid surfactants. Background Technology

[0002] Amino acid surfactants are a class of green surfactants derived from renewable biomass. Compared with traditional surfactants, they not only have superior surface properties, but also have good biocompatibility, low toxicity, and rapid degradation. They are currently widely used in personal care detergents, cosmetics, medical and health products, food, pesticide formulation, and mineral flotation, and have broad development prospects.

[0003] Currently, conventional amino acid surfactants are mainly classified into alanine, glycine, glutamic acid, and sarcosine derivatives. Based on the different raw materials and principles of synthesis, their synthesis processes are mainly divided into direct and indirect methods. The direct method involves the direct dehydration condensation reaction of amino acids with fatty acids (esters, anhydrides) to obtain amino acid surfactants. This method is simple and the raw materials are readily available, but it suffers from harsh reaction conditions, high energy consumption, and low reaction yield. The indirect method mainly involves the Schott-Baumann condensation reaction, where fatty acyl chlorides and amino acids react in alkaline aqueous solutions or organic reagents to obtain the product. This method requires the introduction of acyl chlorides, which can easily cause environmental pollution, and it is also cumbersome, has a long process flow, and low product yield. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a novel amino acid surfactant and its preparation method. This preparation method can be carried out spontaneously at room temperature and pressure, is simple in process, and uses readily available raw materials. The resulting amino acid surfactant possesses a variety of biological activities, including antibacterial, anti-inflammatory, and antioxidant properties.

[0005] The technical solution of the present invention is as follows:

[0006] A novel amino acid surfactant having any of the following structural formulas:

[0007]

[0008] Wherein, R1 is a side chain group of a catechol compound; R2 is a side chain group of an amino acid, wherein the catechol compound is selected from any one of 4-tert-butylcatechol, ethyl caffeate, and phenethyl caffeate, and the amino acid is selected from any one of lysine, arginine, histidine, leucine, alanine, serine, threonine, proline, methionine, glycine, isoleucine, valine, phenylalanine, tyrosine, asparagine, glutamine, tryptophan, cysteine, aspartic acid, and glutamic acid.

[0009] In the above structural formula, the Michael addition reaction between the amino group and the benzene ring of the amino group of the amino group preferentially occurs at the 6th position, and the Michael addition reaction between the thiol group and the benzene ring preferentially occurs at the 5th position.

[0010] In the surfactant of the present invention, the catechin compound portion can form the hydrophobic portion of the surfactant, and the amino acid portion can form the hydrophilic portion of the surfactant, thereby possessing surface-active properties.

[0011] According to some preferred embodiments of the present invention, the novel amino acid surfactant has any of the following structural formulas:

[0012]

[0013]

[0014]

[0015] This invention further provides a method for preparing a novel amino acid surfactant, comprising:

[0016] An anion exchange resin loaded with periodate was obtained as an oxidant;

[0017] The oxidant is reacted with an acetonitrile solution of catechol compounds and a dehydrating agent at 10–40 °C to obtain an acetonitrile solution of o-benzoquinone compounds.

[0018] An acetonitrile solution of the o-benzoquinone compound was reacted with an aqueous solution of amino acids at 10–30 °C, and the reaction product was extracted to obtain the novel amino acid surfactant.

[0019] In the above preparation methods, the catechin compounds are catechins or catechin derivatives.

[0020] According to some preferred embodiments of the present invention, the preparation method further includes: when the aqueous solution of the amino acid is acidic or neutral, first adjusting its pH to 10, and then reacting it with an acetonitrile solution of the o-benzoquinone compound at 10-30°C.

[0021] According to some preferred embodiments of the present invention, the oxidant is obtained by: activating anion exchange resin and mixing it with an aqueous solution of periodate at room temperature until the ion exchange is completed, separating the anion exchange resin loaded with periodate and washing and drying it to obtain the oxidant.

[0022] More preferably, the periodate is selected from sodium periodate.

[0023] More preferably, the anion exchange resin is selected from strong base anion exchange resins such as Amberlite IRA402 resin.

[0024] According to some preferred embodiments of the present invention, the concentration of the acetonitrile solution of the catechol compounds is 25-200 mmol / L.

[0025] According to some preferred embodiments of the present invention, the concentration of the amino acid aqueous solution is 2 to 500 mmol / L.

[0026] According to some preferred embodiments of the present invention, the molar ratio of the catechol compound to the periodate ion loaded on the oxidant is 1:3 to 8.

[0027] According to some preferred embodiments of the present invention, the molar ratio of the o-benzoquinone compound to the amino acid is 1:1 to 8.

[0028] According to some preferred embodiments of the present invention, the extraction reaction product comprises: reacting an acetonitrile solution of the o-benzoquinone compound with an aqueous solution of amino acids at 10–30°C, drying the resulting reaction mixture at 40–60°C, dissolving the obtained solid in water and separating the insoluble matter therein, and freeze-drying the resulting clear liquid to obtain the novel amino acid surfactant.

[0029] According to some preferred embodiments of the present invention, the catechol compound is selected from one or more of 4-tert-butylcatechol, ethyl caffeate, and phenethyl caffeate.

[0030] According to some preferred embodiments of the present invention, the amino acid is selected from one or more of lysine, arginine, histidine, leucine, alanine, serine, threonine, proline, methionine, glycine, isoleucine, valine, phenylalanine, tyrosine, asparagine, glutamine, tryptophan, cysteine, aspartic acid, and glutamic acid.

[0031] According to some preferred embodiments of the present invention, the dehydrating agent is selected from anhydrous sodium sulfate.

[0032] The preparation method of this invention first oxidizes catechol compounds to obtain highly active electron-deficient o-benzoquinone. Then, through Michael addition, Schiff base reaction, and Strecker degradation reactions between o-benzoquinone and nucleophilic functional groups of amino acids (such as amino groups), and Michael addition reaction of the thiol group, covalent linkage between the catechol and amino groups is achieved, resulting in an amino acid surfactant with surface-active properties. Simultaneously, in the first oxidation step, sodium periodate can only function in protic solvents; its direct reaction efficiency in acetonitrile is very low. Therefore, periodate is prepared as an oxidant by resin loading, which avoids the influence of water on the stability of the o-benzoquinone compound and greatly improves the efficiency of the oxidation reaction. In subsequent reactions, the reaction between quinone and amino groups can proceed spontaneously at room temperature and pressure. Therefore, the entire process is mild, does not require high temperature and pressure, is simple, and has a short process flow, allowing for convenient and rapid preparation of the product.

[0033] The novel amino acid surfactant obtained by the preparation method of the present invention has a hydrophobic chain that differs from conventional amino acid surfactants. It is a natural catechin rather than a conventional fatty acid chain, which not only makes the raw materials easier to obtain, but also endows the amino acid surfactant with a variety of biological activities such as antibacterial, anti-inflammatory, and antioxidant properties.

[0034] The present invention has the following beneficial effects:

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] (1) The preparation method of the present invention is carried out at room temperature and pressure, with low equipment requirements, low energy consumption, relatively simple process conditions, and short reaction time, which can make up for the defects of complex processes in existing technologies to a certain extent.

[0037] (2) The preparation method of the present invention can realize the spontaneous synthesis of o-benzoquinone and amino acids to obtain amino acid surfactants, and the process is green and environmentally friendly.

[0038] (3) The amino acid surfactant prepared by this invention has a novel structure, which is significantly different from the existing amino acid surfactant structure and is closer to the quinone-amino acid adduct in the body, and has good biological activity.

[0039] (4) The hydrophobic chain of the amino acid surfactant prepared by the present invention is different from that of conventional amino acid surfactants. It is a natural substance of catechol, with excellent biological safety. Moreover, the obtained amino acid surfactant has excellent surface properties, with excellent foaming and emulsifying properties. Attached Figure Description

[0040] Figure 1 This is a primary mass spectrum of the amino acid surfactant prepared in Example 1 under positive ion mode.

[0041] Figure 2 This is a secondary mass spectrum of the amino acid surfactant prepared in Example 1 under positive ion mode.

[0042] Figure 3 This is the primary mass spectrum of the amino acid surfactant prepared in Example 1 under negative ion mode.

[0043] Figure 4 This is a secondary mass spectrum of the amino acid surfactant prepared in Example 1 under negative ion mode.

[0044] Figure 5 The surface tension diagrams of the amino acid surfactant solution prepared in Example 1 at different concentrations are shown.

[0045] Figure 6 The foam volume diagrams are for the amino acid surfactants prepared in Examples 2 / 3 / 6 / 7 / 8 / 9.

[0046] Figure 7 The foam volume diagram shows the amino acid surfactants prepared in Examples 10-15.

[0047] Figure 8 The foam volume diagrams are of the amino acid surfactants prepared in Examples 16-21.

[0048] Figure 9 The foam volume diagram shows the amino acid surfactants prepared in Examples 22-27.

[0049] Figure 10 The foam volume diagrams are for the amino acid surfactants prepared in Examples 28-33.

[0050] Figure 11 The foam volume diagram shows the amino acid surfactants prepared in Examples 34 / 35 / 38 / 39. Detailed Implementation

[0051] The present invention will now be described in detail with reference to embodiments and accompanying drawings. However, it should be understood that the embodiments and drawings are for illustrative purposes only and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations included within the inventive spirit of the present invention fall within the scope of protection of the present invention.

[0052] Example 1

[0053] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions, which is used as an oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as solvent and a 500 mM lysine solution with deionized water as solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.4 mL of lysine solution, and stir for 20 min. After the reaction was completed, the reaction solution was dried in an oven at 40-60℃, then deionized water was added to dissolve it. The resulting suspension was centrifuged, and the clear supernatant was freeze-dried to obtain two amino acid surfactant products with the structural formulas (1) and (2).

[0054] The amino acid surfactant prepared in this embodiment was characterized using a Shimadzu LC-MS / MS system 8040. Its primary mass spectra in positive and negative ion modes are shown below. Figure 1 , Figure 3 As shown, the secondary mass spectra in positive and negative ion modes are as follows: Figure 2 , Figure 4 As shown.

[0055] It can be seen that in positive ion mode, Figure 1 The peak at the +411 mass-to-charge ratio is consistent with the molecular weight of the predicted Schiff base reaction product, and is further confirmed by... Figure 2 Secondary mass spectrometry analysis of this peak confirmed that phenethyl caffeate reacted with lysine in a Schiff base reaction.

[0056] In negative ion mode Figure 3 The peak of the mass-to-charge ratio of -427 is consistent with the molecular weight of the product of the predicted Michael addition reaction, and is further confirmed by... Figure 4 Secondary mass spectrometry analysis of this peak confirmed that caffeic acid phenethyl ester and lysine underwent a Michael addition reaction simultaneously.

[0057] The structures of the two reactions above successfully linked hydrophobic groups and hydrophilic head groups, confirming that this embodiment successfully prepared a novel amino acid surfactant.

[0058] Example 2

[0059] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 250 mM arginine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.8 mL of arginine solution, and stir for 20 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, whose structural formula is (3).

[0060] Example 3

[0061] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 200 mM histidine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 1 mL of histidine solution, and stir for 20 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (4).

[0062] Example 4

[0063] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 100 mM leucine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 10 °C for 20 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 10 °C, add 2 mL of leucine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (5).

[0064] Example 5

[0065] The amino acid surfactant was prepared using the same preparation process as in Example 4, except that the amino acid solution was a 100 mM leucine solution at pH 10, and the reaction was stirred for 40 min after adding the leucine solution. The resulting amino acid surfactant has the structural formula (5).

[0066] Example 6

[0067] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as solvent and a 500 mM alanine solution with deionized water as solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.4 mL of alanine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, whose structural formula is (6).

[0068] Example 7

[0069] The amino acid surfactant was prepared using the same preparation process as in Example 6, except that the amino acid solution was a 500 mM alanine solution at pH 10, and the reaction was stirred for 40 min after the alanine solution was added. The resulting amino acid surfactant has the structural formula (6).

[0070] Example 8

[0071] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 500 mM serine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.4 mL of serine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (7).

[0072] Example 9

[0073] The amino acid surfactant was prepared using the same preparation process as in Example 8, except that the amino acid solution was a 500 mM serine solution at pH 10, and the reaction was stirred for 40 min after adding the serine solution. The resulting amino acid surfactant has the structural formula (7).

[0074] Example 10

[0075] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 500 mM threonine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.4 mL of threonine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (8).

[0076] Example 11

[0077] The amino acid surfactant was prepared using the same preparation process as in Example 10, except that the amino acid solution was a 500 mM threonine solution at pH 10, and the reaction was stirred for 40 min after the threonine solution was added. The resulting amino acid surfactant has the structural formula (8).

[0078] Example 12

[0079] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 500 mM proline solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.4 mL of proline solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (9).

[0080] Example 13

[0081] The amino acid surfactant was prepared using the same preparation process as in Example 12, except that the amino acid solution was a 500 mM proline solution at pH 10, and the reaction was stirred for 40 min after adding the proline solution. The resulting amino acid surfactant has the structural formula (9).

[0082] Example 14

[0083] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 250 mM methionine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.8 mL of methionine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (10).

[0084] Example 15

[0085] The amino acid surfactant was prepared using the same preparation process as in Example 14, except that the amino acid solution was a 250 mM methionine solution at pH 10, and the reaction was stirred for 40 min after the methionine solution was added. The resulting amino acid surfactant has the structural formula (10).

[0086] Example 16

[0087] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM phenethyl caffeate solution with acetonitrile as the solvent, and a 500 mM glycine solution with deionized water as the solvent. Take 10 mL of the above phenethyl caffeate solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 2 mL of glycine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (11).

[0088] Example 17

[0089] The amino acid surfactant was prepared using the same preparation process as in Example 16, except that the amino acid solution was a 500 mM glycine solution at pH 10, and the reaction was stirred for 40 min after the glycine solution was added. The resulting amino acid surfactant has the structural formula (11).

[0090] Example 18

[0091] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 100 mM isoleucine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 2 mL of isoleucine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (12).

[0092] Example 19

[0093] The amino acid surfactant was prepared using the same preparation process as in Example 18, except that the amino acid solution was a 100 mM isoleucine solution at pH 10, and the reaction was stirred for 40 min after the isoleucine solution was added. The resulting amino acid surfactant has the structural formula (12).

[0094] Example 20

[0095] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 500 mM valine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.4 mL of valine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (13).

[0096] Example 21

[0097] The amino acid surfactant was prepared using the same preparation process as in Example 20, except that the amino acid solution was a 500 mM valine solution at pH 10, and the reaction was stirred for 40 min after the valine solution was added. The resulting amino acid surfactant has the structural formula (13).

[0098] Example 22

[0099] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM phenethyl caffeate solution using acetonitrile as the solvent, and a 50 mM phenylalanine solution using deionized water as the solvent. Take 10 mL of the above phenethyl caffeate solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 4 mL of phenylalanine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (14).

[0100] Example 23

[0101] The amino acid surfactant was prepared using the same preparation process as in Example 22, except that the amino acid solution was a 50 mM phenylalanine solution at pH 10, and the reaction was stirred for 40 min after the phenylalanine solution was added. The resulting amino acid surfactant has the structural formula (14).

[0102] Example 24

[0103] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM phenethyl caffeate solution with acetonitrile as the solvent, and a 2 mM tyrosine solution with deionized water as the solvent. Take 10 mL of the above phenethyl caffeate solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 90 mL of tyrosine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (15).

[0104] Example 25

[0105] The amino acid surfactant was prepared using the same preparation process as in Example 24, except that the amino acid solution was a 2 mM tyrosine solution at pH 10, and the reaction was stirred for 40 min after the tyrosine solution was added. The resulting amino acid surfactant has the structural formula (15).

[0106] Example 26

[0107] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM phenethyl caffeate solution with acetonitrile as the solvent and a 20 mM asparagine solution with deionized water as the solvent. Take 10 mL of the above phenethyl caffeate solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 10 mL of asparagine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (16).

[0108] Example 27

[0109] The amino acid surfactant was prepared using the same preparation process as in Example 4, except that the amino acid solution was a 20 mM asparagine solution at pH 10, and the reaction was stirred for 40 min after adding the asparagine solution. The resulting amino acid surfactant has the structural formula (16).

[0110] Example 28

[0111] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM phenethyl caffeate solution with acetonitrile as the solvent, and a 200 mM glutamine solution with deionized water as the solvent. Take 10 mL of the above phenethyl caffeate solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 1 mL of glutamine solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (17).

[0112] Example 29

[0113] The amino acid surfactant was prepared using the same preparation process as in Example 28, except that the amino acid solution was a 200 mM glutamine solution at pH 10, and the reaction was stirred for 40 min after adding the glutamine solution. The resulting amino acid surfactant has the structural formula (17).

[0114] Example 30

[0115] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 10 mM tryptophan solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 20 mL of tryptophan solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (18).

[0116] Example 31

[0117] The amino acid surfactant was prepared using the same preparation process as in Example 30, except that the amino acid solution was a 10 mM tryptophan solution at pH 10, and the reaction was stirred for 40 min after adding the tryptophan solution. The resulting amino acid surfactant has the structural formula (18).

[0118] Example 32

[0119] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 100 mM cysteine ​​solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 30 °C, add 2 mL of cysteine ​​solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain two amino acid surfactant products with structural formulas (19) and (20).

[0120] Example 33

[0121] The amino acid surfactant was prepared using the same preparation process as in Example 32, except that the amino acid solution was a 100 mM cysteine ​​solution at pH 10, and the reaction was stirred for 40 min after the cysteine ​​solution was added. The resulting amino acid surfactant has the structural formulas (19) and (20).

[0122] Example 34

[0123] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 20 mM aspartic acid solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 10 mL of aspartic acid solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (21).

[0124] Example 35

[0125] The amino acid surfactant was prepared using the same preparation process as in Example 34, except that the amino acid solution was a 20 mM aspartic acid solution at pH 10, and the reaction was stirred for 40 min after the aspartic acid solution was added. The resulting amino acid surfactant has the structural formula (21).

[0126] Example 36

[0127] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 40 mM glutamic acid solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 10 °C for 20 min, and then filter to obtain about 8 mL of clear solution. Place this solution in a constant temperature water bath at 10 °C, add 5 mL of glutamic acid solution, and stir for 60 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (22).

[0128] Example 37

[0129] The amino acid surfactant was prepared using the same preparation process as in Example 36, except that the amino acid solution was a 40 mM glutamic acid solution at pH 10, and the reaction was stirred for 40 min after the glutamic acid solution was added. The resulting amino acid surfactant has the structural formula (22).

[0130] Example 38

[0131] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 200 mM 4-tert-butylcatechol solution with acetonitrile as solvent, and a 500 mM lysine solution with deionized water as solvent. Take 10 mL of the above 4-tert-butylcatechol solution, add 500 mg of anhydrous sodium sulfate and 12 g of the above-prepared oxidant, react in a constant temperature water bath at 40 °C for 20 min, and then filter to obtain about 4 mL of clear solution. Place this solution in a constant temperature water bath at 30 °C, add 1.6 mL of lysine solution, and stir for 10 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (23).

[0132] Example 39

[0133] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 100 mM ethyl caffeate solution with acetonitrile as the solvent, and a 500 mM lysine solution with deionized water as the solvent. Take 10 mL of the above ethyl caffeate solution, add 500 mg of anhydrous sodium sulfate and 6 g of the above-prepared oxidant, react in a constant temperature water bath at 40 °C for 12 min, and then filter to obtain about 6 mL of clear solution. Place this solution in a constant temperature water bath at 30 °C, add 1.2 mL of lysine solution, and stir for 20 min. After the reaction is completed, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant, which has the structural formula (24).

[0134] Example 40

[0135] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate ions as the oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution with acetonitrile as the solvent, and a 500 mM lysine solution with deionized water as the solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate, and then add 1 g, 2 g, 3 g, and 4 g of the above-prepared oxidant respectively. React in a constant temperature water bath at 25 °C for 15 min, and then filter to obtain about 6 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.3 mL of lysine solution, and stir for 20 min. After the reaction is complete, the reaction solution is dried in an oven at 40-60℃, then deionized water is added to dissolve it. The resulting suspension is centrifuged, and the clear supernatant is freeze-dried to obtain the amino acid surfactant.

[0136] Example 41

[0137] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain the resin loaded with periodate ions as the oxidant. Prepare 12.5 mM, 25 mM, 37.5 mM, and 50 mM caffeic acid phenethyl ester solutions using acetonitrile as solvent, and prepare a 500 mM lysine solution using deionized water as solvent. Take 10 mL of the above-mentioned 12.5 mM, 25 mM, 37.5 mM, and 50 mM caffeic acid phenethyl ester solutions, add 500 mg of anhydrous sodium sulfate, and then add 1.5 g, 3 g, 4.5 g, and 6 g of the oxidant prepared above, respectively. React in a constant temperature water bath at 25 °C for 15 min, then filter to obtain approximately 6 mL of clear solution. Place this solution in a constant temperature water bath at 20 °C, add 0.3 mL of lysine solution, and stir for 20 min. After the reaction is complete, dry the reaction solution in an oven at 40-60 °C, then dissolve it in deionized water. Centrifuge the resulting suspension, and freeze-dry the clear supernatant to obtain the amino acid surfactant.

[0138] Example 42

[0139] Prepare 250 mL of 80 g / L sodium periodate aqueous solution, add 30 g (wet weight) of activated Amberlite IRA402 anion exchange resin, and stir at room temperature for 6 h. Then wash the resin successively with deionized water and tetrahydrofuran until the solution is clear, and dry at 40 °C for 12 h to obtain resin loaded with periodate, which is used as an oxidant. Prepare a 25 mM caffeic acid phenethyl ester solution using acetonitrile as solvent, and prepare 25 mM, 50 mM, 100 mM, and 500 mM lysine solutions using deionized water as solvent. Take 10 mL of the above caffeic acid phenethyl ester solution, add 500 mg of anhydrous sodium sulfate and 3 g of the above-prepared oxidant, react in a constant temperature water bath at 25 °C with a stirrer for 15 min, and then filter to obtain about 8 mL of clear solution. The solution was placed in a 20°C constant temperature water bath with a stirrer, and 0.4 mL of 25 mM, 50 mM, 100 mM, and 500 mM lysine solutions were added respectively. The mixture was stirred for 20 min. After the reaction was completed, the reaction solution was dried in an oven at 40-60°C, then dissolved in deionized water. The resulting suspension was centrifuged, and the clear supernatant was freeze-dried to obtain the amino acid surfactant.

[0140] The amino acid surfactants and control samples obtained in the above examples were tested as follows:

[0141] (1) Surface tension test:

[0142] Multiple aqueous solutions of the amino acid surfactant prepared in Example 1 were prepared according to concentration gradients. The surface tension of the solutions was measured at 20°C using a BZY-1 automatic surface tension meter. The test results are as follows: Figure 5 As shown, the surface tension of the amino acid surfactant solution obtained in Example 1 gradually decreases with increasing concentration and eventually stabilizes. At this point, the surfactant concentration is the critical micelle concentration, which is approximately 0.60 mM, and the surface tension is approximately 47.04 mN / m, indicating that the obtained surfactant has excellent surface properties.

[0143] In addition, 1 mM aqueous solutions of the amino acid surfactants prepared in Examples 4, 5, 36, and 37 were prepared, and the surface tension of the solutions was measured at 20°C using a BZY-1 automatic surface tension meter. The test results are shown in Table 1 below. It can be seen that the obtained surfactants can significantly reduce the surface tension of water and have excellent surface properties.

[0144] Table 1. Surface tension test results of amino acid surfactants (1 mM)

[0145] Example 4 Example 5 Example 36 Example 37 Surface tension mN / m 41.21 43.86 56.39 45.27

[0146] (2) Emulsification performance test:

[0147] The amino acid surfactants prepared in Examples 1, 4, 5, 36, and 37 were prepared at 1 mM. 40 mL of each solution was added to a 100 mL stoppered graduated cylinder at room temperature (25°C), followed by an equal amount of liquid paraffin. The mixture was vigorously shaken up and down 30 times and then allowed to stand. The time from the start of standing to the separation of 10 mL of aqueous phase was recorded using a stopwatch. A commercially available sodium cocoyl glutamate of the same concentration was used as a control. The test results are shown in Table 2. It can be seen that the amino acid surfactants prepared in the examples require a longer time to separate 10 mL of aqueous phase after mixing with liquid paraffin, indicating excellent emulsifying properties.

[0148] Table 2. Emulsification time of liquid paraffin by amino acid surfactants and control samples.

[0149] sample Emulsification time (s) Example 1 340 Example 4 165 Example 5 232 Example 36 31 Example 37 166 Sodium cocoyl glutamate 102

[0150] (3) Foam performance test:

[0151] 1 mM of the amino acid surfactants prepared in Examples 1, 4, 5, 36, and 37 was prepared. 20 mL of each surfactant was added to a 250 mL stoppered graduated cylinder at room temperature (25°C). The stopper was closed, and the cylinder was vigorously shaken up and down 15 times. Foaming properties were observed, and the foam height at 0 min, 5 min, and 10 min was recorded. A commercially available sodium cocoyl glutamate of the same concentration was used as a control. The test results are shown in Table 3. It can be seen that the amino acid surfactants prepared in the examples have good foaming properties and foam stability.

[0152] Table 3. Foaming properties of amino acid surfactants and control samples.

[0153]

[0154] In addition, 1 mM of the amino acid surfactants prepared in Examples 2, 3, 6-35, 38, and 39 was prepared.

[0155] At room temperature (25°C), add 20 mL of the solution to a 250 mL stoppered graduated cylinder, seal the stopcock, and shake vigorously up and down.

[0156] Observe the foaming properties 15 times, and record the foam height at 0 minutes. The test results are as follows: Figure 6-11 As shown, it can be seen that

[0157] The amino acid surfactant prepared in the examples has good foaming properties.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Any changes made without departing from the spirit and principle of the present invention are not permitted.

[0159] Modifications, substitutions, combinations, and simplifications should all be equivalent substitutions and are included within the scope of protection of this invention.

[0160] Within.

Claims

1. A method for preparing an amino acid surfactant, characterized in that, It includes: An anion exchange resin loaded with periodate was obtained as an oxidant; The oxidant is reacted with an acetonitrile solution of catechol compounds and a dehydrating agent at 10–40 °C to obtain an acetonitrile solution of o-benzoquinone compounds. An acetonitrile solution of the o-benzoquinone compound was reacted with an aqueous solution of amino acids at 10–30 °C, and the reaction product was extracted to obtain an amino acid surfactant. The oxidant is obtained by: activating a strong base anion exchange resin and mixing it with an aqueous solution of periodate at room temperature until the ion exchange is completed, separating the anion exchange resin loaded with periodate and washing and drying it to obtain the oxidant. The catechins are selected from phenethyl caffeate; The amino acid surfactant has any of the following structural formulas: Wherein, R1 is a side chain group of a catechol compound; R2 is a side chain group of an amino acid, which is selected from any one of lysine, arginine, histidine, leucine, alanine, serine, threonine, proline, methionine, glycine, isoleucine, valine, phenylalanine, tyrosine, asparagine, glutamine, tryptophan, cysteine, aspartic acid, and glutamic acid.

2. The preparation method according to claim 1, characterized in that, The amino acid surfactant has any of the following structural formulas:

3. The preparation method according to claim 1, characterized in that, It also includes: when the aqueous solution of the amino acid is acidic or neutral, first adjust its pH to 10, and then react it with the acetonitrile solution of the o-benzoquinone compound at 10-30°C.

4. The preparation method according to claim 1, characterized in that, The periodate is selected from sodium periodate.

5. The preparation method according to claim 1, characterized in that, in, The concentration of the acetonitrile solution of the catechol compounds is 25–200 mmol / L; and / or the concentration of the aqueous solution of the amino acids is 2–500 mmol / L.

6. The preparation method according to claim 1, characterized in that, in, The molar ratio of catechol compounds to periodate loaded on the oxidant is 1:3 to 8; and / or, the molar ratio of o-benzoquinone compounds to amino acids is 1:1 to 8.

7. The preparation method according to claim 1, characterized in that, The extraction reaction product comprises: reacting an acetonitrile solution of the o-benzoquinone compound with an aqueous solution of amino acids at 10–30°C, drying the resulting reaction mixture at 40–60°C, dissolving the obtained solid in water and separating the insoluble matter, and freeze-drying the resulting clear liquid to obtain the amino acid surfactant.

8. The preparation method according to any one of claims 1-7, characterized in that, The dehydrating agent is selected from anhydrous sodium sulfate.

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