A degradable surfactant based on methyl palmitate, and a preparation method and application thereof

Abstract

The application discloses a kind of degradable surfactant based on methyl palmitate and its preparation method and application, belong to surfactant technical field.The acid amide compound is obtained by catalytic reaction after methyl palmitate is mixed with amine compound;Then the acid amide compound is mixed with the composite quaternary ammonium reagent consisting of alkylating agent and long-chain alkyl glycoside, and is reacted under the stirring condition of 60~80 DEG C, 200~500 r / min, to prepare the degradable surfactant based on methyl palmitate.The mild and efficient preparation is realized by catalyst and composite quaternary ammonium, and the obtained surfactant has excellent surface activity, good foam stability and high biodegradation rate, and the performance is better than single quaternary ammonium product, and can be widely applied in detergent, cosmetics, textile auxiliaries and petroleum exploitation auxiliaries and other fields.

Description

Technical Field

[0001] This invention belongs to the field of surfactant preparation technology, specifically relating to a biodegradable surfactant based on methyl palmitate, its preparation method, and its application. Background Technology

[0002] Surfactants are a class of compounds with amphiphilic structures, widely used in detergents, cosmetics, textiles, and petroleum industries. Currently, most commercially available surfactants use petrochemical products as raw materials, which suffers from complex synthesis steps, high production costs, and poor biodegradability. Methyl palmitate, as an extract of natural plant oils, is widely available, inexpensive, and has good biocompatibility. Using it as a raw material to prepare surfactants can effectively solve the aforementioned shortcomings of traditional surfactants.

[0003] While existing technologies have attempted to prepare surfactants using fatty acids and amine compounds via amidation and quaternization reactions—for example, Chinese patent application CN102503848A—uses fatty acids and hydroxyethyl ethylenediamine as raw materials, performing an amidation reaction at a high temperature of 120–180°C, followed by a quaternization reaction with sodium chloroacetate solution. However, this method suffers from high reaction temperatures and high energy consumption, and the use of a single quaternizing agent results in insufficient product performance control, failing to meet the precise requirements of different application scenarios. Furthermore, the preparation of existing methyl palmitate-based surfactants also suffers from unstable product yields and poor synergy between foam stability and surface activity. Therefore, developing a simple, mild, and precisely controllable method for preparing biodegradable surfactants based on methyl palmitate is of significant practical importance. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a biodegradable surfactant based on methyl palmitate, its preparation method and application, so as to solve the technical problems of high reaction temperature, high energy consumption, unstable product yield and poor synergy between foam stability and surface activity in the preparation process of existing fatty acid-based surfactants.

[0005] To achieve the above objectives, the present invention employs the following technical solution: The first aspect of this invention discloses a method for preparing a biodegradable surfactant based on methyl palmitate, comprising the following steps: 1) Methyl palmitate is mixed with amine compounds and catalyzed to obtain palmitamide compounds; 2) A palmitic acid amide compound and a complex quaternizing agent were mixed in a molar ratio of 1:(1.05~1.15) and then heated to react, resulting in a biodegradable surfactant based on methyl palmitate; The composite quaternizing agent is composed of an alkylating agent and a long-chain alkyl glycoside in a mass ratio of (8~9):(1~2); the long-chain alkyl glycoside has an average degree of polymerization of 1.2~1.4 and an alkyl chain carbon number of 8~10.

[0006] Preferably, in step 1), the amine compound is any one of monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, and propylenediamine.

[0007] Preferably, in step 1), the catalyst is any one of sodium ethoxide, sodium isopropoxide, and sodium methoxide.

[0008] Preferably, in step 1), the molar ratio of methyl palmitate to amine compound is 1:(1.1~1.3), and the amount of catalyst added is 0.5%~1% of the total mass of raw materials.

[0009] Preferably, in step 1), the reaction is carried out at 90~100℃ for 4~5 hours.

[0010] Preferably, in step 2), the alkylating agent is any one of dimethyl sulfate, 1-chloromethylnaphthalene, sodium 3-chloro-2-hydroxypropanesulfonate, and sodium chloroacetate.

[0011] Preferably, in step 2), the molar ratio of palmitic acid amide compound to complex quaternizing agent is 1:1.1.

[0012] Preferably, in step 2), the mass ratio of the alkylating agent to the long-chain alkyl glycoside in the complex quaternizing agent is 8.5:1.5.

[0013] Preferably, in step 2), the solvent in the heating reaction is any one of ethanol, isopropanol, and N,N-dimethylformamide.

[0014] Preferably, in step 2), the reaction is carried out under stirring conditions at 60-80°C for 3-4 hours.

[0015] More preferably, in step 2), the stirring speed is 200~500 r / min.

[0016] In a second aspect, the present invention discloses a method for preparing a biodegradable surfactant based on methyl palmitate.

[0017] A third aspect of the present invention discloses the application of the above-described biodegradable surfactant in the preparation of detergents, cosmetics, textile auxiliaries or petroleum exploitation auxiliaries.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for preparing a biodegradable surfactant based on methyl palmitate. 1) The preparation of palmitamide compounds using methyl palmitate and amine compounds under catalytic conditions is key to constructing the hydrophilic skeleton of the surfactant. This step, combined with a complex quaternization synergistic system, achieves mild and efficient preparation. Compared to the high-temperature reaction conditions of existing technologies, this method significantly reduces the reaction temperature, decreases energy consumption, ensures sufficient amide group formation, and improves product purity. The yield of palmitamide compounds can reach over 94%. 2) The biodegradable surfactant is prepared by reacting palmitamide compounds with a complex quaternization reagent composed of an alkylating agent and a long-chain alkyl glycoside. The introduction of long-chain alkyl glycosides on the basis of the alkylating agent enhances the uniformity of the reaction system, promotes the full quaternization reaction, and stabilizes the product yield at over 90%. Furthermore, the specific degree of polymerization and carbon chain length of the alkyl glycosides can form a precise hydrophilic-hydrophobic match with the quaternary ammonium groups of the alkylating agent, allowing for precise control of the hydrophobic-hydrophilic balance of the surfactant and optimizing its synergistic performance of surface activity and foam stability. The three factors work synergistically to achieve high activity, high stability, and high biodegradability. The surfactant obtained by this method exhibits excellent surface activity (surface tension 25~28 mN / m), good foam stability (foam height 50~60 mm at 0 min, retention rate over 85% at 5 min), and high biodegradability (88%~92% after 28 days). It outperforms single quaternized products and can be widely used in detergents, cosmetics, textile auxiliaries, and petroleum extraction auxiliaries. In the detergent field, it can improve detergency and make rinsing easier; in the cosmetic field, it can enhance emulsion stability; in the textile auxiliaries field, it can improve the hydrophilic or hydrophobic finishing effect of fabrics; and in the petroleum extraction field, it can help reduce interfacial tension. It demonstrates broad industrial applicability and can solve the problems of poor environmental performance of traditional petroleum-based surfactants and insufficient controllability of existing methyl palmitate-based products, combining environmental friendliness and practicality.

[0019] Furthermore, the amine compound can be any one of monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, and propylenediamine. Different amine compounds can introduce different numbers of hydroxyl or amino groups to further adjust the reactivity of palmitic amide compounds and the hydrophilicity of the final product. Compared with the single hydroxyethyl ethylenediamine in the prior art, the amine compound selection range of this method is wider, and the product performance can be diversified and controlled.

[0020] Furthermore, the molar ratio of methyl palmitate to amine compounds is 1:1.2. This optimized ratio can further reduce raw material waste and improve the yield and purity of palmitamide compounds, with a yield of over 95%.

[0021] Furthermore, the reaction temperature is 70~75℃ and the reaction time is 3.5 hours. This parameter range can maximize the synergistic effect of the composite quaternizing reagent, avoid incomplete local reactions, and ensure the uniformity of product performance.

[0022] Furthermore, the molar ratio of palmitic acid amide compounds to the complex quaternizing reagent is 1:1.1. This ratio can avoid product impurities caused by excessive quaternizing reagent, while ensuring that the reaction proceeds fully and improving product purity.

[0023] Furthermore, the mass ratio of the alkylating agent to the long-chain alkyl glycoside in the composite quaternizing agent is 8.5:1.5. At this ratio, the synergistic effect of the alkylating agent and the long-chain alkyl glycoside is the best, which can further reduce the surface tension of the surfactant and significantly improve the foam stability.

[0024] The biodegradable surfactant provided by this invention uses natural methyl palmitate as the raw material skeleton. Through the synergistic effect of composite quaternizing agents, it has excellent surface activity (surface tension 25~28 mN / m), good foam stability (foam height 50~60 mm at 0 min, retention rate over 85% at 5 min), and high biodegradability (biodegradation rate can reach 88%~92% after 28 days). Moreover, it does not contain harmful impurities from petrochemical sources, which is in line with the trend of green and environmentally friendly applications. Detailed Implementation

[0025] To enable those skilled in the art to understand the features and effects of the present invention, the following description and definitions are only general descriptions of the terms and expressions mentioned in the specification. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0027] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0028] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0029] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0030] This invention provides a method for preparing a biodegradable surfactant based on methyl palmitate, which is achieved through a two-step reaction, specifically including: 1. Amide reaction: Methyl palmitate and amine compounds are mixed in a molar ratio of 1:(1.1~1.3), and then 0.5%~1% of catalyst is added according to the total mass of the raw materials. The mixture is reacted at 90~100℃ for 4~5 hours to obtain palmitate amide compounds. The amine compound is any one of monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, and propylenediamine; preferably, the molar ratio of methyl palmitate to the amine compound is 1:1.2; the catalyst is any one of sodium ethoxide, sodium isopropoxide, and sodium methoxide.

[0031] 2. Quaternization reaction: The palmitic amide compound obtained in step 1 is mixed with the composite quaternizing agent at a molar ratio of 1:(1.05~1.15), and reacted at 60~80℃ and 200~500 r / min for 3~4 hours to obtain a biodegradable surfactant based on methyl palmitate. The composite quaternizing reagent is composed of a main reagent and an auxiliary reagent in a mass ratio of (8~9):(1~2). The main reagent is an alkylating reagent, preferably any one of dimethyl sulfate, 1-chloromethylnaphthalene, sodium 3-chloro-2-hydroxypropanesulfonate (CHPS), and sodium chloroacetate. The auxiliary reagent is a long-chain alkyl glycoside with an average degree of polymerization of 1.2~1.4 and an alkyl chain carbon number of 8~10. Preferably, the molar ratio of palmitic amide compound to composite quaternizing reagent is 1:1.1. The mass ratio of main reagent to auxiliary reagent of composite quaternizing reagent is 8.5:1.5. The reaction temperature is 70~75℃, the reaction time is 3.5 hours, and the stirring rate is 300~400 r / min.

[0032] Preferably, both steps 1 and 2 support solvent-free or solvent-based conditions; wherein the solvent is selected from any one of ethanol, isopropanol and N,N-dimethylformamide; solvent-free conditions can simplify the process and reduce environmental treatment costs, while solvent-based conditions are suitable for scenarios where raw material mixing is difficult and improve the homogeneity of the reaction system.

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading this description, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0034] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications in the art, unless otherwise stated.

[0035] I. Preparation of biodegradable surfactants based on methyl palmitate Example 1 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol of methyl palmitate and 1.2 mol of monoethanolamine were mixed, and 0.8% sodium methoxide was added according to the total mass of the raw materials. The mixture was reacted at 95°C for 4.5 hours to obtain palmitic acid monoethanolamide with a yield of 96.2%.

[0036] 2. Quaternization reaction: 1.00 mol of palmitic acid monoethanolamide obtained in step 1, 0.945 mol of dimethyl sulfate and 0.105 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and reacted at 70℃ with stirring at 350 r / min for 3.5 hours to obtain biodegradable surfactant A with a yield of 93.8%.

[0037] Example 2 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.2 mol diethanolamine were mixed, and 0.8% sodium methoxide was added according to the total mass of the raw materials. The mixture was reacted at 95°C for 4.5 hours to obtain palmitic acid diethanolamide with a yield of 96.5%.

[0038] 2. Quaternization reaction: 1.000 mol of palmitic acid diethanolamide obtained in step 1, 0.945 mol of 1-chloromethylnaphthalene and 0.105 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and reacted at 60℃ with stirring at 400 r / min for 3.5 hours to obtain biodegradable surfactant B with a yield of 92.9%.

[0039] Example 3 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.3 mol triethanolamine were mixed, and 0.5% sodium methoxide was added as part of the total mass of the raw materials. The mixture was reacted at 100℃ for 5 hours to obtain triethanolamine palmitate with a yield of 95.3%.

[0040] 2. Quaternization reaction: 1.000 mol of palmitic acid triethanolamide obtained in step 1, 0.935 mol of sodium 3-chloro-2-hydroxypropanesulfonate and 0.165 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and reacted at 80℃ with stirring at 200 r / min for 3.5 hours to obtain biodegradable surfactant C with a yield of 94.2%.

[0041] Example 4 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.1 mol ethylenediamine were mixed and 0.9% sodium methoxide was added according to the total mass of the raw materials. The mixture was reacted at 90℃ for 4 hours to obtain ethylenediamine palmitate amide with a yield of 96.0%.

[0042] 2. Quaternization reaction: 1.000 mol of palmitic acid ethylenediamine amide obtained in step 1, 0.920 mol of dimethyl sulfate and 0.230 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and reacted at 65℃ with stirring at 500 r / min for 3 hours to obtain biodegradable surfactant D with a yield of 92.1%.

[0043] Example 5 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.2 mol propylenediamine were mixed and 0.9% sodium methoxide was added according to the total mass of the raw materials. The mixture was reacted at 90℃ for 4 hours to obtain palmitic propylenediamine amide with a yield of 96.1%.

[0044] 2. Quaternization reaction: 1.000 mol of palmitic acid propylenediamine amide obtained in step 1, 0.930 mol of dimethyl sulfate and 0.190 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and reacted at 65℃ with stirring at 350 r / min for 3 hours to obtain biodegradable surfactant E with a yield of 93.5%.

[0045] Example 6 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.3 mol monoethanolamine were mixed, and 0.5% sodium methoxide was added according to the total mass of the raw materials. Then, the mixture was dissolved in ethanol with a mass equal to that of methyl palmitate. The mixture was reacted at 100°C for 5 hours to obtain palmitic acid monoethanolamide with a yield of 95.1%.

[0046] 2. Quaternization reaction: 1.000 mol of palmitic acid monoethanolamide obtained in step 1, 0.983 mol of 1-chloromethylnaphthalene and 0.147 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and dissolved in ethanol at 1 times the mass of palmitic acid monoethanolamide. The mixture was stirred at 75°C and 400 r / min for 3.5 hours to obtain biodegradable surfactant F with a yield of 91.8%.

[0047] Example 7 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.1 mol diethanolamine were mixed, and 0.7% sodium ethoxide of the total mass of the raw materials were added. Then, the mixture was dissolved in isopropanol at 1.2 times the mass of methyl palmitate and reacted at 90°C for 4 hours to obtain palmitate diethanolamide with a yield of 95.6%.

[0048] 2. Quaternization reaction: 1.000 mol of palmitic acid diethanolamide obtained in step 1, 0.912 mol of sodium 3-chloro-2-hydroxypropanesulfonate and 0.228 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and dissolved in isopropanol in 1.2 times the mass of palmitic acid diethanolamide. The mixture was stirred at 300 r / min at 70℃ for 3 hours to obtain biodegradable surfactant G with a yield of 92.7%.

[0049] Example 8 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.2 mol triethanolamine were mixed, and sodium isopropoxide catalyst of 0.6% of the total mass of the raw materials was added. Then, the mixture was dissolved in N,N-dimethylformamide (DMF) at 0.8 times the mass of methyl palmitate. The mixture was reacted at 100°C for 5 hours to obtain triethanolamide palmitate with a yield of 94.7%.

[0050] 2. Quaternization reaction: 1.000 mol of palmitic acid triethanolamide obtained in step 1, 0.920 mol of sodium chloroacetate and 0.230 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and dissolved in N,N-dimethylformamide at 0.8 times the mass of palmitic acid triethanolamide. The mixture was stirred at 450 r / min at 80℃ for 4 hours to obtain biodegradable surfactant H with a yield of 90.9%.

[0051] Example 9 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.2 mol ethylenediamine were mixed and 0.7% sodium methoxide was added according to the total mass of the raw materials. The mixture was reacted at 95°C for 4.5 hours to obtain palmitic acid ethylenediamine amide with a yield of 96.3%.

[0052] 2. Quaternization reaction: 1.000 mol of palmitic acid ethylenediamine amide obtained in step 1, 1.035 mol of dimethyl sulfate and 0.115 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and reacted at 70℃ with stirring at 300 r / min for 3.5 hours to obtain biodegradable surfactant I with a yield of 94.0%.

[0053] Example 10 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.5 mol propylenediamine were mixed and 0.5% sodium methoxide was added according to the total mass of the raw materials. The mixture was reacted at 100℃ for 5 hours to obtain palmitic diamine amide with a yield of 95.8%.

[0054] 2. Quaternization reaction: 1.000 mol of palmitic acid propylenediamine amide obtained in step 1, 0.912 mol of 1-chloromethylnaphthalene, and 0.228 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and reacted at 80℃ with stirring at 400 r / min for 4 hours to obtain biodegradable surfactant J with a yield of 92.5%.

[0055] Example 11 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol methyl palmitate and 1.2 mol monoethanolamine were mixed, and sodium methoxide of 1.0% of the total mass of the raw materials was added. The mixture was reacted at 90°C for 4 hours to obtain palmitic acid monoethanolamide with a yield of 95.8%.

[0056] 2. Quaternization reaction: 1.000 mol of palmitic acid monoethanolamide obtained in step 1, 0.960 mol of sodium 3-chloro-2-hydroxypropanesulfonate and 0.190 mol of alkyl glycoside (alkyl glycoside 0810, purchased from Shandong Yousuo Chemical Technology Co., Ltd.) were mixed and reacted at 65℃ with stirring at 350 r / min for 3 hours to obtain biodegradable surfactant K with a yield of 93.2%.

[0057] Comparative Example 1 A method for preparing a biodegradable surfactant based on methyl palmitate includes the following steps: 1. Amide reaction: 1.0 mol of methyl palmitate and 1.2 mol of monoethanolamine were mixed, and 0.8% sodium methoxide was added according to the total mass of the raw materials. The mixture was reacted at 95°C for 4.5 hours to obtain palmitic acid monoethanolamide with a yield of 85.7%.

[0058] 2. Quaternization reaction: 1.000 mol of palmitic acid monoethanolamide prepared in step 1 and 1.400 mol of dimethyl sulfate were mixed and stirred at 350 r / min at 70℃ for 3.5 hours to obtain biodegradable surfactant L with a yield of 89%.

[0059] II. Performance Testing of Biodegradable Surfactants The biodegradable surfactants A to K prepared in Examples 1 to 11 and the biodegradable surfactant L prepared in Comparative Example 1 were subjected to performance tests. The test items included surface tension (25°C), foam height (Roche foam apparatus, 0 min / 5 min), and biodegradation rate (28 days). The results are shown in Table 1. Table 1 Performance test results of biodegradable surfactants

[0060] As can be seen from Table 1, the core performance indicators of biodegradable surfactants A to K are excellent: 1) Surface tension (25℃) was 25.6~29.1 mN / m, significantly lower than Comparative Example 1, indicating superior surface activity; foam height (Roche foam apparatus) was 50~60 mm at 0 min and 43~52 mm at 5 min, with a foam retention rate of 5 min ( The biodegradability exceeds 85% (compared to 76%), significantly improving foam stability. The biodegradability rate (28 days) is 88%~92%, both meeting the requirements for environmentally friendly surfactants (≥80%) specified in GB / T15818-2006, highlighting its green attributes.

[0061] 2) Highly controllable performance: By adjusting the main reagent type and the combination of amine compounds in the composite quaternizing reagent, the core performance of the surfactant can be precisely controlled. If low surface tension (25~27 mN / m) and high foaming are required, the composite system of "CHPS / dimethyl sulfate + ethylenediamine / triethanolamine" is preferred; if a low foaming system is required, the composite system of "sodium chloroacetate + monoethanolamine" can be selected, which is suitable for different application scenarios (such as low foaming for cosmetics and high foaming for detergents).

[0062] 3) Solvent-free systems have greater advantages: Samples prepared under solvent-free conditions (A, B, C, D, E, I, J, K) are superior to samples containing solvents (F, G, H) in terms of surface tension and biodegradability. Moreover, the process is simpler, more environmentally friendly, and more suitable for industrial promotion.

[0063] 4) Balancing Green and Performance: All samples exhibited a biodegradability rate exceeding 88%, and their surface tension was significantly lower than that of traditional products and existing methyl palmitate-based products. This achieved a triple balance of high surface activity, high foam stability, and high biocompatibility, making them widely applicable in detergents, cosmetics, and other fields where both environmental protection and performance are required. The above test results demonstrate that the methyl palmitate-based biodegradable surfactant prepared in this invention possesses excellent surface activity, foam stability, and biodegradability, showing promising application prospects.

[0064] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A method for preparing a biodegradable surfactant based on methyl palmitate, characterized in that, Includes the following steps: 1) Methyl palmitate is mixed with amine compounds and reacted under catalysis to obtain palmitamide compounds; 2) A palmitic acid amide compound and a complex quaternizing agent were mixed in a molar ratio of 1:(1.05~1.15) and then heated to react, resulting in a biodegradable surfactant based on methyl palmitate; The composite quaternizing agent is composed of an alkylating agent and a long-chain alkyl glycoside in a mass ratio of (8~9):(1~2); the long-chain alkyl glycoside has an average degree of polymerization of 1.2~1.4 and an alkyl chain carbon number of 8~10.

2. The method for preparing a biodegradable surfactant based on methyl palmitate according to claim 1, characterized in that, In step 1), the amine compound is any one of monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, and propylenediamine.

3. The method for preparing a biodegradable surfactant based on methyl palmitate according to claim 1, characterized in that, In step 1), the catalyst is any one of sodium ethoxide, sodium isopropoxide, and sodium methoxide.

4. The method for preparing a biodegradable surfactant based on methyl palmitate according to claim 1, characterized in that, In step 1), the molar ratio of methyl palmitate to amine compounds is 1:(1.1~1.3), and the amount of catalyst added is 0.5%~1% of the total mass of raw materials.

5. A method for preparing a biodegradable surfactant based on methyl palmitate according to any one of claims 1 to 4, characterized in that, In step 2), the alkylating agent is any one of dimethyl sulfate, 1-chloromethylnaphthalene, sodium 3-chloro-2-hydroxypropanesulfonate, and sodium chloroacetate.

6. A method for preparing a biodegradable surfactant based on methyl palmitate according to any one of claims 1 to 4, characterized in that, In step 2), the molar ratio of palmitic acid amide compound to complex quaternizing reagent is 1:1.

1.

7. A method for preparing a biodegradable surfactant based on methyl palmitate according to any one of claims 1 to 4, characterized in that, In step 2), the mass ratio of the alkylating agent to the long-chain alkyl glycoside in the complex quaternizing agent is 8.5:1.

5.

8. A method for preparing a biodegradable surfactant based on methyl palmitate according to any one of claims 1 to 4, characterized in that, In step 2), the solvent in the heating reaction is any one of ethanol, isopropanol, and N,N-dimethylformamide.

9. A biodegradable surfactant prepared by the method for preparing a biodegradable surfactant based on methyl palmitate as described in any one of claims 1 to 8.

10. The use of the biodegradable surfactant of claim 9 in the preparation of detergents, cosmetics, textile auxiliaries or petroleum exploitation auxiliaries.

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