Environment-responsive amphoteric surfactant and method for preparing the same
By preparing alkyl diamines and acrylates through double bond addition and substitution reactions, and controlling the preparation process by adjusting the pH value, the problem of unclear response mechanisms of existing amphoteric surfactants has been solved, and surface activity regulation and enhancement under different environments have been achieved.
Patent Information
- Application Number
- CN202211518622.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-29
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2042-11-29
AI Technical Summary
Existing environmentally responsive amphoteric surfactants have unclear response mechanisms, are expensive, have limited applications, and are difficult to effectively regulate surface activity in various environments.
An amphoteric surfactant with environmental responsiveness was formed by a double bond addition reaction of alkyl diamine, acrylate and methanol, followed by a substitution reaction with chloroacetic acid and acetone. The preparation process of the surfactant was controlled by adjusting the pH value.
It achieves reversible changes in the surface activity of surfactants under different environments, exhibits high surface activity and multiple aggregation morphologies, and is suitable for various environments, especially with significantly enhanced water solubility under alkaline and heating conditions.
Smart Images
Figure BDA0003970990490000021 
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of surfactant technology, specifically relating to an environmentally responsive amphoteric surfactant and its preparation method. Background Technology
[0002] Surfactants are chemical substances that, in solution, have lipophilic groups aggregate inward to form a core, while hydrophilic groups, in contact with water, arrange on the outside. They adsorb at the solution's surface / interface, significantly reducing the surface / interfacial tension, thus performing a series of functions such as foaming / defoaming, solubilizing, and wetting. Environmentally responsive amphoteric surfactants are those whose molecules simultaneously contain acidic and basic groups, readily forming internal salts. These surfactants incorporate functional groups that respond to environmental stimuli (such as pH, temperature, ultraviolet light, additives, etc.). Temperature and pH are easily controllable environmental factors. By adjusting the temperature and pH of the system, changes in molecular structure can be achieved, thereby controlling micelle formation, surface activity, and aggregate morphology, and making the process reversible. They are commonly used in daily life, industry, agriculture, and high technology. While multi-responsive systems exist, their response mechanisms are not fully understood, they are relatively expensive, and their practical application range is smaller than other types of surfactants. Summary of the Invention
[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide an environmentally responsive amphoteric surfactant and its preparation method, which can realize the corresponding change of surface activity according to the changes of environmental pH and temperature, and the response mechanism has intelligent responsiveness, which endows the surfactant with functionalization and has a wide range of applications.
[0004] To achieve the above objectives, the present invention employs the following technical solution:
[0005] This invention provides an environmentally responsive amphoteric surfactant, the structural formula of which is as follows:
[0006]
[0007] Wherein, R1 is a C3, C6, or C9 n-alkyl group, and R2 is a C1, C16, or C18 n-alkyl group.
[0008] This invention provides a method for preparing the aforementioned environmentally responsive amphoteric surfactant, comprising the following steps:
[0009] S1: The alkyl chain diamine, acrylate and methanol are stirred evenly to carry out a double bond addition reaction. After the double bond addition reaction is completed, post-processing is performed to obtain intermediate product I.
[0010] S2: Intermediate product I, chloroacetic acid and acetone are stirred evenly and a substitution reaction is carried out. After the substitution reaction is completed, the pH value is adjusted to obtain a reaction solution. Then, the solution is concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0011] In a further step of the present invention, in S1, the alkyl chain diamine is one or more of propylene diamine, hexamethylene diamine, and nonadiamine; and the acrylate is one or more of methyl acrylate, hexadecyl acrylate, and octadecyl acrylate.
[0012] In a further step of the present invention, in S1, the molar ratio of the alkyl diamine, acrylate and methanol is 1:(4-4.5):15.
[0013] In a further step of the present invention, in S1, the reaction temperature of the double bond addition reaction is 30-50°C, and the reaction time of the double bond addition reaction is 6-8 hours.
[0014] In a further step of the present invention, in step S1, the post-treatment consists of vacuum distillation, washing 1 to 3 times, and vacuum drying; the washing is performed using ethyl acetate.
[0015] Furthermore, in step S2, the molar ratio of intermediate product I, chloroacetic acid, and acetone is 1:(2-2.5):15.
[0016] In a further embodiment of the present invention, in step S2, the reaction temperature of the substitution reaction is 100–130°C, and the reaction time of the substitution reaction is 6–8 h.
[0017] In a further step of the present invention, in step S2, the pH value is adjusted using a 1 mol / L NaOH solution; the pH value is 8 to 10.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] This invention discloses an environmentally responsive amphoteric surfactant. Compared with traditional single-chain surfactants, this environmentally responsive amphoteric surfactant has a symmetrical molecular structure, high surface activity, and can form various aggregation forms in solution. The surfactant can effectively reduce the surface tension of the solution, more easily aggregate to form micelles, has a low Kraff point, good compound synergistic effect, and good calcium soap dispersion properties.
[0020] The environmentally responsive amphoteric surfactant described in this invention can adjust its surface activity according to changes in ambient temperature and pH. This surfactant has low surface activity at low temperatures and is an oil-soluble surfactant; when the ambient environment is alkaline or heated, the ester groups hydrolyze, and the surface activity is significantly enhanced, making it a water-soluble surfactant. The response mechanism is clear and it can be used in a variety of environments. Attached Figure Description
[0021] Figure 1 This is a diagram illustrating the synthesis mechanism of the environmentally responsive amphoteric surfactant in Example 3 of the present invention;
[0022] Figure 2 This is a diagram illustrating the synthesis mechanism of the environmentally responsive amphoteric surfactant in Example 6 of the present invention.
[0023] Figure 3 This is a graph showing the surface tension of the environmentally responsive amphoteric surfactant obtained in Example 3 of the present invention as a function of temperature and pH.
[0024] Figure 4 This is a schematic diagram illustrating the synthesis mechanism of the environmentally responsive amphoteric surfactant of the present invention.
[0025] Figure 5 The surfactant of this invention can adapt to changes in environmental pH and temperature. Detailed Implementation
[0026] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. 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.
[0027] 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.
[0028] 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.
[0029] 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.”
[0030] 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.
[0031] This invention provides an environmentally responsive amphoteric surfactant and its preparation method.
[0032] 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 the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.
[0033] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to mass ratio.
[0034] A method for preparing an environmentally responsive amphoteric surfactant includes the following steps:
[0035] (1) Under ice-water bath conditions, alkyl chain diamine, acrylate and methanol were added sequentially to a 250 mL three-necked flask, stirred evenly, heated to 30-50 °C and refluxed for double bond addition reaction for 6-8 h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0036] (2) Add intermediate product I, chloroacetic acid and acetone to a 250 mL three-necked flask, stir well, and reflux at 100-130 °C for 6-8 h for substitution reaction. After the reaction is completed, adjust the pH value to 8-10 with 1 mol / L NaOH solution, concentrate the reaction solution under reduced pressure, and dry under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0037] As a further improvement of the present invention, in step (1), the alkyl chain diamine is one or more of propylene diamine, hexamethylene diamine, and nonadiamine; the acrylate is one or more of methyl acrylate, hexadecyl acrylate, and octadecyl acrylate; and the molar ratio of alkyl chain diamine, acrylate, and methanol is 1:(4-4.5):15.
[0038] As a further improvement of the present invention, in step (2), the molar ratio of intermediate product I, chloroacetic acid and acetone is 1:(2~2.5):15.
[0039] like Figure 4 As shown, the specific reaction equation of this invention is as follows:
[0040]
[0041] Wherein, R1 is a C3, C6, or C9 n-alkyl group, and R2 is a C1, C16, or C18 n-alkyl group.
[0042] Based on the above reaction mechanism, this invention discloses an environmentally responsive amphoteric surfactant, the structural formula of which is:
[0043]
[0044] Wherein R1 is a C3, C6, or C9 n-alkyl group, and R2 is a C1, C16, or C18 n-alkyl group.
[0045] like Figure 5 As shown, the environmentally responsive amphoteric surfactant undergoes hydrolysis under alkaline and heated conditions, losing its hydrophobic n-alkane group and increasing the content of hydrophilic carboxylate, thus enhancing its surface activity. The surfactant's surface activity changes accordingly with variations in ambient temperature and pH. At low temperatures, this environmentally responsive amphoteric surfactant exhibits low surface activity and is oil-soluble; however, under alkaline and heated conditions, the ester groups hydrolyze, significantly enhancing its surface activity and making it water-soluble.
[0046]
[0047] The surfactant described in this invention can change its surface activity according to changes in environmental pH and temperature, and can be applied in the field of tertiary oil recovery.
[0048] The present invention will be further described below with reference to specific embodiments and accompanying drawings:
[0049] Example 1
[0050] (1) Under ice-water bath conditions, 7.9 g of 1,9-nonanediamine, 17.2 g of methyl acrylate and 30 mL of methanol were added sequentially to a 250 mL three-necked flask, stirred evenly, heated to 30 °C and refluxed for 6 h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0051] (2) 6.3g of intermediate product I, 4.7g of chloroacetic acid and 30mL of acetone were added to a 250mL three-necked flask, stirred evenly, and refluxed at 100℃ for 6h. After the reaction was completed, the pH value was adjusted to 8 with 1mol / L NaOH solution, the reaction solution was concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0052] Example 2
[0053] (1) Under ice-water bath conditions, 7.9 g of 1,9-nonanediamine, 18.5 g of methyl acrylate and 35 mL of methanol were added sequentially to a 250 mL three-necked flask, stirred evenly, heated to 40 °C and refluxed for 6 h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0054] (2) 6.6 g of intermediate product I, 5.4 g of chloroacetic acid and 30 mL of acetone were added to a 250 mL three-necked flask, stirred evenly, and refluxed at 110 °C for 6 h. After the reaction was completed, the pH value was adjusted to 9 with 1 mol / L NaOH solution, the reaction solution was concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0055] Example 3
[0056] (1) Under ice-water bath conditions, 7.9 g of 1,9-nonanediamine, 19.4 g of methyl acrylate and 40 mL of methanol were added sequentially to a 250 mL three-necked flask, stirred evenly, heated to 50 °C and refluxed for 6 h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0057] (2) 6.8 g of intermediate product I, 5.9 g of chloroacetic acid and 30 mL of acetone were added to a 250 mL three-necked flask, stirred evenly, and refluxed at 120 °C for 6 h. After the reaction was completed, the pH value was adjusted to 10 with 1 mol / L NaOH solution, the reaction solution was concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0058] Example 4
[0059] (1) Under ice-water bath conditions, 7.9 g of 1,9-nonanediamine, 19.4 g of methyl acrylate and 40 mL of methanol were added sequentially to a 250 mL three-necked flask, stirred evenly, heated to 50 °C and refluxed for 8 h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0060] (2) 6.8 g of intermediate product I, 5.9 g of chloroacetic acid and 30 mL of acetone were added to a 250 mL three-necked flask, stirred evenly, and refluxed at 120 °C for 8 h. After the reaction was completed, the pH value was adjusted to 10 with 1 mol / L NaOH solution, the reaction solution was concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0061] Example 5
[0062] (1) Under ice-water bath conditions, 3.7g of 1,3-propanediamine, 65g of octadecyl acrylate and 100mL of methanol were added sequentially to a 250mL three-necked flask, stirred evenly, heated to 30℃ and refluxed for 6h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0063] (2) 17.17g of intermediate product I, 4.7g of chloroacetic acid and 30mL of acetone were added to a 250mL three-necked flask, stirred evenly, and refluxed at 100℃ for 6h. After the reaction was completed, the pH value was adjusted to 8 with 1mol / L NaOH solution, the reaction solution was concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0064] Example 6
[0065] (1) Under ice-water bath conditions, 3.7 g of 1,3-propanediamine, 69.8 g of octadecyl acrylate and 110 mL of methanol were added sequentially to a 250 mL three-necked flask, stirred evenly, heated to 40 °C and refluxed for 6 h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0066] (2) 18.4 g of intermediate product I, 5.4 g of chloroacetic acid and 30 mL of acetone were added to a 250 mL three-necked flask, stirred evenly, and refluxed at 110 °C for 6 h. After the reaction was completed, the pH value was adjusted to 9 with 1 mol / L NaOH solution, the reaction solution was concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0067] Example 7
[0068] (1) Under ice-water bath conditions, 3.7 g of 1,3-propanediamine, 72.9 g of octadecyl acrylate and 120 mL of methanol were added sequentially to a 250 mL three-necked flask, stirred evenly, heated to 50 °C and refluxed for 6 h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0069] (2) 19.2g of intermediate product I, 5.9g of chloroacetic acid and 30mL of acetone were added to a 250mL three-necked flask, stirred evenly, and refluxed at 130℃ for 6h. After the reaction was completed, the pH value was adjusted to 10 with 1mol / L NaOH solution, the reaction solution was concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0070] Example 8
[0071] (1) Under ice-water bath conditions, 3.7 g of 1,3-propanediamine, 72.9 g of octadecyl acrylate and 120 mL of methanol were added sequentially to a 250 mL three-necked flask, stirred evenly, heated to 50 °C and refluxed for 8 h, methanol was removed by vacuum distillation, washed three times with ethyl acetate, and dried under vacuum to obtain intermediate product I.
[0072] (2) 19.2g of intermediate product I, 5.9g of chloroacetic acid and 30mL of acetone were added to a 250mL three-necked flask, stirred evenly, and refluxed at 130℃ for 8h. After the reaction was completed, the pH value was adjusted to 10 with 1mol / L NaOH solution, the reaction solution was concentrated under reduced pressure and dried under vacuum to constant weight to obtain an environmentally responsive amphoteric surfactant.
[0073] Testing and Analysis:
[0074] To characterize the structural features of this environmentally responsive amphoteric surfactant, the surfactants synthesized in Examples 3 and 6 were subjected to 1H NMR spectroscopy. The results are as follows.
[0075] Example 3
[0076] 1H NMR (300MHz, DMSO): δ3.66 (s, 4H), 4.18 (d, 8H), 3.22 (t, 12H),
[0077] 1.71 (m, 4H), 1.29 (m, 4H) ppm.
[0078] Example 6
[0079] 1H NMR (300MHz, DMSO): δ 1.43 (s, 4H), 0.88 (t, 8H), 1.26 (t, 12H), 3.22 (t, 8H), 2.17 (t, 4H), 4.13 (m, 4H) ppm.
[0080] To characterize the surface activity of this surfactant, the surface, interface, and CMC results of the products synthesized mainly from 1,9-nonadiamine, methyl acrylate, 1,3-propanediamine, and octadecyl acrylate are shown in Table 1.
[0081] Table 1
[0082]
[0083] The results show that the surface tension reduction ability of this environmentally responsive amphoteric surfactant gradually increases with the growth of the hydrophobic carbon chain. The amphoteric surfactant exhibits better surface activity, mainly because with the growth of the hydrophobic chain, the symmetrical twin structure has multiple ionic head groups, and the linking groups are connected by chemical bonds. The multiple monomer surfactant molecules are more tightly linked, and stronger interactions are generated between the hydrophobic chains, resulting in lower surface / interfacial tension of the surfactant.
[0084] The present invention describes the change in surface activity of the amphoteric surfactant with variations in ambient temperature and pH, such as... Figure 3 As shown, Figure 3 This represents the change in surface tension of a surfactant solution with temperature and pH. Figure 3 It can be seen that the surface tension of the surfactant solution first increases and then decreases as the temperature and pH value increase. When the temperature is 80℃ and the pH is 10, the surface tension reaches a minimum of 28.5 mN / m, indicating that the surfactant has strong surface activity under heated and alkaline conditions.
[0085] 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 the claims of this invention.
Claims
1. An environmentally responsive amphoteric surfactant characterized in that, The structural formula of the environment-responsive amphoteric surfactant is as follows: In the formula, R1 is a normal alkyl group with C3, C6 or C9, and R2 is a normal alkyl group with C1, C16 or C18.
2. A process for the preparation of the environmentally responsive amphoteric surfactant of claim 1, characterized by, The method comprises the following steps: S1: stirring an alkyl chain diamine, an acrylic ester and methanol uniformly to perform a double bond addition reaction, performing post-treatment after the double bond addition reaction is completed, and obtaining an intermediate product I; S2: stirring the intermediate product I, chloroacetic acid and acetone uniformly to perform a substitution reaction, adjusting a pH value after the substitution reaction is completed, obtaining a reaction solution, and performing vacuum drying after vacuum concentration to a constant weight, and obtaining the environment-responsive amphoteric surfactant.
3. The method of claim 2, wherein the method is characterized by, In the S1, the alkyl chain diamine is one or more of propylene diamine, hexamethylene diamine and nonamethylene diamine; and the acrylic ester is one or more of methyl acrylate, cetyl acrylate and stearyl acrylate.
4. The method for preparing an environmentally responsive amphoteric surfactant according to claim 2, characterized in that, In the S1, the molar ratio of the alkyl chain diamine, the acrylic ester and the methanol is 1:(4-4.5):
15.
5. The method for preparing an environmentally responsive amphoteric surfactant according to claim 2, characterized in that, In the S1, the reaction temperature of the double bond addition reaction is 30-50°C, and the reaction time of the double bond addition reaction is 6-8h.
6. The method for preparing an environmentally responsive amphoteric surfactant according to claim 2, characterized in that, In the S1, the post-treatment is vacuum drying after vacuum distillation and washing 1-3 times; and the washing is performed with ethyl acetate.
7. The method for preparing an environmentally responsive amphoteric surfactant according to claim 2, characterized in that, In the S2, the molar ratio of the intermediate product I, the chloroacetic acid and the acetone is 1:(2-2.5):
15.
8. The method for preparing an environmentally responsive amphoteric surfactant according to claim 2, characterized in that, In the S2, the reaction temperature of the substitution reaction is 100-130°C, and the reaction time of the substitution reaction is 6-8h.
9. The method for preparing an environmentally responsive amphoteric surfactant according to claim 2, characterized in that, In the S2, the pH value is adjusted with a 1 mol / L NaOH solution; and the pH value is 8-10.