A rosin-based, switchable CO2 / N2 responsive surfactant, its preparation method and its uses

Abstract

The application discloses a rosin-based CO2 / N2 response type surfactant with switchable two ends, a preparation method and application thereof, and the rosin-based CO2 / N2 response type surfactant with switchable two ends is abbreviated as NMPAN, and the molecular structure is as follows: the NMPAN is prepared by twice imidization reactions of male pimaric acid and N, N-dimethylethylenediamine under different conditions. The surfactant has good response performance to CO2 / N2 at room temperature, and compared with the reported rosin-based CO2 / N2 response type surfactant, the response speed is fast and the condition is mild. The application also discloses the Pickering emulsification performance of the surfactant, and after the surfactant is changed into a cationic surfactant by passing CO2, the surfactant can be used in cooperation with nano silicon oxide to stabilize Pickering emulsion, the situation that the emulsion cannot be stabilized by the nano particles or the surfactant alone is changed, and the use amount of the surfactant and the nano particles is significantly reduced; the prepared limonene essential oil Pickering emulsion can be stable for more than 6 months at room temperature, and the embedding and slow release of the limonene essential oil are realized.

Description

Technical Field

[0001] This invention relates to a rosin-based CO2 / N2 responsive surfactant, its preparation method, and its applications, belonging to the field of green surfactant technology. Background Technology

[0002] With the increasing demand in various fields for rapid transitions between "stable" and "demulsified" states in emulsions, research on stimulus-responsive Pickering emulsions is gaining increasing attention. Among these, CO2 / N2 triggering offers advantages such as low cost, environmental friendliness, and good biocompatibility. CO2-responsive emulsion systems refer to emulsion systems where the emulsion state cycles repeatedly between "stable" and "demulsified" states under the influence of CO2. Essentially, it is also a form of pH triggering; CO2 dissolves in water to form carbonic acid, lowering the pH value, and then, under certain conditions, inert gas or air is bubbled in to remove CO2, raising the pH value. Compared to traditional pH triggering mechanisms, there are no neutralization product residues in the system, making it more environmentally friendly, economical, easy to remove, and renewable. Furthermore, CO2-responsive emulsifiers can theoretically be reused after removing the crude oil phase and introducing a new oil phase, meeting the requirements of green and energy-saving processing, and providing a new and efficient strategy for oil transportation in high-temperature regions.

[0003] Emulsion delivery systems have been successfully applied in the encapsulation and sustained-release of plant essential oils. Plant essential oils possess antibacterial and antioxidant properties, showing promise in the food, daily chemical, and pharmaceutical industries. In the food sector, due to the potential health risks of synthetic food additives, attention has turned to natural plant essential oils. Plant essential oils can be used as natural flavorings in everyday foods such as candies, baked goods, and pastries, stimulating appetite. To expand the application of essential oils in the food industry, Pickering emulsion delivery systems are used for encapsulation, addressing issues such as volatility, water insolubility, and strong odor.

[0004] However, in existing reports, most gas-responsive surfactants use petroleum-based surfactants as raw materials, with fewer reports on gas-responsive surfactants prepared from natural renewable resources, especially carbon dioxide-responsive surfactants prepared from rosin. With increasing awareness of environmental protection, using renewable resources instead of petroleum resources to prepare gas-responsive surfactants has become a trend. Summary of the Invention

[0005] The purpose of this invention is to provide a rosin-based CO2 / N2 responsive surfactant, its preparation method and its uses. This invention uses rosin as a raw material to prepare a CO2 responsive surfactant for the preparation of stable Pickering emulsions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A rosin-based, switchable CO2 / N2 responsive surfactant, abbreviated as NMPAN, has the following molecular structure:

[0008]

[0009] At room temperature, when CO2 is bubbled into an aqueous solution of NMPAN, the NMPAN will protonate and transform into N-cations within 30 seconds. + MPAN + ; and then to N + MPAN + When N2 is bubbled into an aqueous solution, the solution becomes turbid within 10 minutes. + MPAN + The deprotonation process reverts to NMPAN, and this process can be repeated. The pH and redox potential of the solution undergo cyclical changes, demonstrating that this surfactant has a good response to CO2 / N2. This surfactant responds extremely quickly to CO2 gas under mild conditions, reducing the amount of CO2 gas used, improving efficiency, and saving costs. The NMPAN response to CO2 / N2 is as follows:

[0010]

[0011] The aforementioned rosin-based CO2 / N2 responsive surfactant has two CO2-responsive tertiary amine groups at both ends, with acid-base titration jump points of pH=3.1 and pH=9.2, respectively.

[0012] The rosin-based, switchable CO2 / N2 responsive surfactant of this application can be used as a pH-responsive adsorbent to adsorb anionic dyes, etc., and then the anionic dyes can be released by adjusting the pH, thereby realizing the recovery of anionic dyes.

[0013] The above-mentioned nonionic NMPAN has a critical micelle concentration of 4 mM and a surface tension of 39.572 mN / m; the cationic N + MPAN + The critical micelle concentration is 6 mM and the surface tension is 36.553 mN / m.

[0014] The aforementioned rosin-based CO2 / N2 responsive surfactant is prepared by a two-stage imidization reaction of maleic acridinium with N,N-dimethylethylenediamine.

[0015] The inventors discovered that, through the above method, a structure can be obtained as follows: This substance has two tertiary amine groups, resulting in an extremely fast response to CO2 gas, taking less than 30 seconds; it has a wider adjustable pH range and two titration jump points; and in synergy with nano-silica, it exhibits excellent Pickering emulsification properties and a significant emulsification effect on limonene.

[0016] As one preferred embodiment, the preparation method of the above-mentioned rosin-based CO2 / N2-responsive surfactant includes the following steps:

[0017] S1, maleic acridin reacts with N,N-dimethylethylenediamine to form MPAN;

[0018] S2 and MPAN undergo acyl chloride reaction with an acyl chloride reagent in an organic solvent, and then undergo imidization reaction with N,N-dimethylethylenediamine in an ice-water bath to generate NMPAN (a rosin-based CO2 / N2 responsive surfactant).

[0019] The above-mentioned maleic anhydride was prepared by an addition reaction of rosin and maleic anhydride. The molar ratio of rosin to maleic anhydride was 1:(1.1–1.3), glacial acetic acid was used as the solvent, the reaction temperature was 130–150℃, the reaction time was 4–5 h, and after cooling, a large amount of glacial acetic acid was added to induce crystallization. The crude maleic anhydride was obtained by filtration, purified by recrystallization with glacial acetic acid 2–3 times, and dried to obtain the final product.

[0020] In step S1 above, the molar ratio of maleic acridinary acid to N,N-dimethylethylenediamine is 1:(1.0-1.5), anhydrous ethanol is used as solvent, the reaction temperature is 60-80℃, the reaction time is 4-6h, and after the reaction is completed, the mixture is filtered and dried to obtain MPAN.

[0021] In step S2 above, the organic solvent is anhydrous dichloromethane, the acyl chloride reagent is oxalyl chloride, the molar ratio of MPAN to oxalyl chloride is 1:(1.5–2.0), the reaction temperature is 25–55℃, the reaction time is 3–6 h, and the acyl chloride product is obtained by rotary evaporation. The molar ratio of the acyl chloride product to N,N-dimethylethylenediamine is 1:(1.0–1.2), dichloromethane is used as the solvent, the reaction temperature is 0–5℃, the reaction time is 2–4 h, after the reaction is completed, the mixture is washed three times with deionized water, and the organic phase is dried by rotary evaporation to obtain NMPAN. No column chromatography purification is required.

[0022] The aforementioned rosin-based, switchable CO2 / N2 responsive surfactants can work in conjunction with charged nanoparticles to prepare CO2 / N2 responsive Pickering emulsions, as well as to encapsulate and slow-release plant essential oils.

[0023] The aforementioned rosin-based, switchable CO2 / N2 responsive surfactant can be used in conjunction with charged nanoparticles to prepare limonene essential oil Pickering emulsions.

[0024] Stable emulsions cannot be obtained by using charged nanoparticles alone or by using the surfactant alone. However, a rosin-based, switchable CO2 / N2 responsive surfactant, in conjunction with charged nanoparticles, can prepare stable Pickering emulsions and significantly reduce the amount of charged nanoparticles and surfactant required. 0.1–0.5 wt% (relative to aqueous phase) of nano-silica dispersed in different concentrations of N2... + MPAN + In aqueous solution, when equal volumes of aqueous and oil phases are subjected to high shear at 9000–12000 rpm for 1–5 min, the resulting emulsion can remain stable for more than 6 months.

[0025] NMPAN, when dissolved in an aqueous CO2 solution, transforms into cationic bicarbonate. This bicarbonate then interacts with charged nanoparticles under high shear conditions to prepare a Pickering emulsion, which exhibits excellent stability. Charged nanoparticles at concentrations ranging from 0.1% to 1 wt%, such as 0.1 wt%, 0.5 wt%, and 1 wt%, are dispersed in NMPAN at different concentrations. + MPAN + In an aqueous solution, an emulsion is prepared by subjecting equal volumes of aqueous and oil phases to high shear rates of 10,000–12,000 rpm (e.g., 10,000 rpm, 11,000 rpm, 12,000 rpm) for 1–5 min (e.g., 1 min, 3 min, 5 min). When nanoparticles are negatively charged, such as silica, they can react with cationic N2. + MPAN + Pickering emulsions are obtained by adsorbing particles together through electrostatic attraction. The amount of surfactant required to stabilize the emulsion can be greatly reduced compared to ordinary emulsions (which do not contain charged particles).

[0026] The surfactant prepared by this invention uses rosin, a natural resource, as its raw material, which aligns with the concept of green and sustainable development. It incorporates the tricyclic diterpenoid structure of rosin and a tertiary amine group that responds to CO2 / N2. This surfactant can reversibly switch between nonionic and cationic surfactants under CO2 / N2 stimulation. After being converted to a cationic surfactant by introducing CO2, it can be adsorbed onto nanoparticles through electrostatic interactions, thereby preparing a stable Pickering emulsion. This solves the problem that hydrophilic nanoparticles alone cannot stabilize emulsions, thus broadening the application range of rosin-based surfactants.

[0027] Any techniques not mentioned in this invention are based on existing technologies.

[0028] Compared with the prior art, the present invention achieves the following beneficial effects:

[0029] (1) This invention, taking advantage of the structural characteristics of rosin, synthesizes a rosin-based CO2 / N2-responsive surfactant, NMPAN, through a two-stage imidization reaction between maleic acridinium and N,N-dimethylethylenediamine. NMPAN is insoluble in water; when CO2 is introduced into water, H2CO3 is formed, protonating NMPAN to form a water-soluble cationic carbonate. Upon introduction of N2, the CO2 is expelled, and the protonated NMPAN returns to its original tertiary amine state. This process can be repeated. The raw materials are widely available, inexpensive, and environmentally friendly, promoting sustainable development.

[0030] (2) When CO2 is bubbled into an NMPAN aqueous solution, it transforms into a cationic N-type ... + MPAN + Then, due to the effect of electrostatic repulsion, N + MPAN + Its emulsifying properties are superior to those of NMPAN.

[0031] (3) Cation N + MPAN + Stable Pickering emulsions can be prepared under high shear conditions by combining with negatively charged nano-silica in water through electrostatic interaction, which greatly reduces the amount of surfactant and nanoparticles required for emulsion preparation. Attached Figure Description

[0032] Figure 1 This is the infrared spectrum of the NMPAN of the present invention;

[0033] Figure 2 For the NMPAN of this invention 1 H-NMR spectrum;

[0034] Figure 3 The graphs (a) and (b) show the pH / ORP changes of the NMPAN of the present invention with alternating CO2 / N2 introduction;

[0035] Figure 4 This is the acid-base titration curve of the NMPAN of this invention;

[0036] Figure 5 For the present invention N + MPAN + Image showing the preparation of emulsions using synergistic nano-SiO2;

[0037] Figure 6 For the present invention N + MPAN + Demulsification and reemulsification cycle diagram of emulsion prepared by synergistic nano-SiO2

[0038] Figure 7 For the present invention N+ MPAN + Emulsion preparation alone;

[0039] Figure 8 Figure showing the preparation of emulsions for nano-silica alone;

[0040] Figure 9 For the present invention N + MPAN + Figure showing the preparation of limonene emulsion using synergistic nano-silica;

[0041] Figure 10 This is a response diagram of the NMPAN of the present invention to CO2 / N2; Detailed Implementation

[0042] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0043] In all cases, unless otherwise specified, the work was completed at room temperature, which was 20–25°C.

[0044] Example 1

[0045] The synthesis of a rosin-based, switchable CO2 / N2 responsive surfactant includes the following steps:

[0046] (1) Weigh 100g (0.33mol) of refined rosin, 35.6g (0.3625mol) of maleic anhydride, and 40g of glacial acetic acid into a four-necked flask, stir mechanically, and reflux under condensation. Slowly raise the temperature to 140℃ and continue the reaction for 5 hours. After cooling to room temperature, add 100g of glacial acetic acid to crystallize, filter to obtain maleic rosin, recrystallize three times with glacial acetic acid to obtain maleic acridinium (MPA).

[0047] (2) Weigh 10.0 g (0.025 mol) of maleic acrid acid and 150 mL of anhydrous ethanol into a three-necked flask. Then add 3.3 g (0.038 mol) of N,N-dimethylethylenediamine into the three-necked flask. Stir magnetically and reflux under condensation. Raise the temperature to 80 °C and continue the reaction for 5 h. A white solid precipitates out. After the reaction is complete, filter and dry to obtain MPAN with a yield of 85%.

[0048] (3) Weigh 4.7 g (0.010 mol) of MPAN into a three-necked flask, dissolve it in 100 mL of dichloromethane, add 1.90 g (0.015 mol) of oxaloyl chloride, stir magnetically and reflux under condensation. After reacting at 50 °C for 5 h, remove the solvent and excess oxaloyl chloride by rotary evaporation to obtain the acyl chloride product. Add 100 mL of dichloromethane and N,N-dimethylethylenediamine (1.32 g, 0.015 mol), and react in an ice-water bath for 4 h. After the reaction is complete, wash three times with deionized water, and dry the organic phase by rotary evaporation to obtain NMPAN. Its infrared spectrum is shown below. Figure 1 As shown, 2770-2950cm -1 (CH3,CH2), 1697cm -1 (C=O), 1768cm -1 (-CO-N-CO-), 3389cm -1 1636cm -1 and 1522cm -1 (-CO-NH-); 1 HNMR (500MHz, DMSO-D6) such as Figure 2 As shown, with δ 7.39(t, 1H, CO-NH) and 5.33(s, 1H, C=CH), it can be concluded that the target structure was obtained. The yield was 81.3%.

[0049] Example 2

[0050] The responsiveness of NMPAN to CO2 / N2 was determined by cyclic changes in pH and redox potential (ORP) of the NMPAN aqueous solution. The response process of NMPAN (10 mM concentration) to CO2 / N2 is as follows: Figure 3 and Figure 10 As shown. CO2 dissolves in aqueous solution to form H2CO3. The weak acid solution leads to the protonation of the tertiary amine group, generating a charged cationic surfactant N. + MPAN + Within 30 seconds, the solution becomes clear and transparent, with the pH decreasing to approximately 6 and the ORP increasing to approximately 67 mV. When N2 is introduced at room temperature to expel CO2, the weak acidity of the solution disappears, the charged cationic surfactant deprotonates and returns to its initial tertiary amine group state, and the solution becomes turbid within 10 minutes, returning from an ionic to a non-ionic state. Continued aeration returns it to its initial state, with the pH and ORP returning to their initial values ​​of 8 and -53 mV, respectively. When CO2 is introduced again, the pH again decreases to approximately 6 and the ORP increases to approximately 67 mV. This process can be repeated. Figure 3The figure only shows four cycles (the inventors conducted experiments and repeated the cycles 50 times, and the pH and ORP values ​​remained comparable to the initial cycle), indicating that NMPAN has excellent responsiveness to CO2 / N2. Due to its reversible response to CO2, it can be used to prepare bio-based smart responsive materials, etc.

[0051] Example 3

[0052] N was tested using the surface tension method. + MPAN + Surface tension of aqueous solution (γ) cmc The critical micelle concentration (cmc) was obtained. Surface tension is an intrinsic property of liquids, and its magnitude depends mainly on the liquid itself and the types of the other phase it contacts. The magnitude of surface tension reflects the ability of surfactants to reduce the surface tension of liquids. Different concentrations of NMPAN and N... + MPAN + The aqueous solution was prepared and equilibrated in a constant temperature incubator for 24 hours (25±0.5℃). The surface tension of the surfactant was then measured using a Sigma 701 surface tension meter via the DuNoüy ring method. Each concentration was tested in triplicate, and the average value was taken. The test temperature was 25±0.5℃, and the water used was ultrapure water (18.2 MΩ·cm). The test results showed that the critical micelle concentration of the nonionic form NMPAN was 4 mM, and the surface tension was 39.572 mN / m; the surface tension of the cationic form N... + MPAN + The critical micelle concentration is 6 mM and the surface tension is 36.553 mN / m.

[0053] Example 4

[0054] The titration jump point of NMPAN was determined using acid-base titration. NMPAN was dissolved in 0.1 mol·L⁻¹ solution. -1 In an HCl solution, the concentration of NMPAN is 1 g / L, and 0.1 mol·L⁻¹ is used. -1 The pH was determined by titrating with NaOH solution and measuring different volumes of NaOH. An acid-base titration curve was plotted with pH as the y-axis and NaOH volume as the x-axis. Figure 4 As shown, the surfactant NMPAN has two titration jump points, which also confirms that its structure contains two tertiary amine groups, making it more sensitive to CO2 gas and exhibiting a faster response speed.

[0055] Example 5

[0056] Pickering emulsions were prepared, and their stability was observed and recorded using a digital camera. 7 mL of NMPAN aqueous solutions of different concentrations were prepared, and CO2 was bubbled through each solution for 1 minute to completely protonate it, yielding NMPAN. + MPAN +The aqueous solution becomes clear within 30 seconds after CO2 is introduced, indicating complete protonation of NMPAN. The 1-minute CO2 introduction is to obtain stable NMPAN. + MPAN + Aqueous solutions were prepared with concentrations of 0.01, 0.03, 0.06, 0.1, 0.3, 0.6, 1, 3, and 4 mM. 0.5 wt% nano-silica was dispersed in N2O solutions of different concentrations. + MPAN + Add 7 mL of isooctane to the aqueous solution and perform high shear at 11000 rpm for 2 minutes to obtain Pickering emulsion. Record the results by taking photos after 7 days. Figure 5 As shown in the figure (concentrations from left to right are 0.01, 0.03, 0.06, 0.1, 0.3, 0.6, 1, 3, 6 mM). The obtained emulsions were used in a cycle experiment of demulsification and reemulsification, where N was selected. + MPAN + The concentration in aqueous solution is 0.6 mM, such as Figure 6 As shown, the emulsion can undergo multiple emulsification (homogenization after 1 minute of CO2 introduction) and demulsification (N2 introduction for 10 minutes) cycles. This property allows for the recovery and reuse of isooctane; and the resulting emulsion can remain stable for over 6 months. It can also be applied to emulsification and demulsification of emulsions, intelligent response release, dye adsorption and release, dispersion and recovery of easily agglomerated nanoparticles. For example, emulsification can be used to encapsulate and adsorb target anionic dyes, followed by demulsification for release, enabling the recovery and reuse of the target anionic dyes. Furthermore, compared to emulsification using only N2... + MPAN + ( Figure 7 ) or only made of nano-silica ( Figure 8 Compared to emulsions prepared by N, + MPAN + The amount of surfactant and nanoparticles required for the emulsion prepared by synergistic interaction with nano-SiO2 is reduced, and the stability of the emulsion is significantly improved.

[0057] Comparative Example 1

[0058] Prepare 7 mL of NMPAN aqueous solutions of different concentrations, and then pass CO2 through them for 1 minute to completely protonate them to obtain N. + MPAN + Aqueous solutions with concentrations of 0.01, 0.03, 0.06, 0.1, 0.3, 0.6, 1, 3, and 4 mM were added to each solution with 7 mL of isooctane. The mixtures were then subjected to high shear at 11000 rpm for 2 minutes to obtain Pickering emulsions. Photos were taken and recorded after one day. Figure 7 As shown in the figure (the concentrations from left to right are 0.01, 0.03, 0.06, 0.1, 0.3, 0.6, 1, 3, 6 mM).

[0059] Comparative Example 2

[0060] 7 mL of nano-silica aqueous solutions of different concentrations (0.005 wt%, 0.005 wt%, 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, and 1 wt%) were prepared and ultrasonically dispersed. CO2 was bubbled through each solution for 1 minute, followed by the addition of 7 mL of isooctane. The mixture was then subjected to high shear at 11000 rpm for 2 minutes to obtain emulsions. The emulsions were photographed and recorded after one day. Figure 8 As shown in the figure (the concentrations from left to right are 0.01, 0.03, 0.06, 0.1, 0.3, 0.6, 1, 3, 6 mM).

[0061] The results in the graph show that: N + MPAN + When it exists alone ( Figure 7 Even at a concentration of 6 mM, the emulsion completely breaks down after 24 hours of preparation, failing to maintain its stability; the nano-SiO2 aqueous dispersion exists alone ( Figure 8 Even at a concentration of 1 wt%, the emulsion completely breaks down after 24 hours of preparation, failing to maintain its stability; however, when N... + MPAN + When working synergistically with nano-SiO2 ( Figure 5 The concentration of nano-SiO2 was fixed at 0.5 wt%, and N... + MPAN + A good and stable emulsion can be prepared at room temperature with a concentration of only 1 mM.

[0062] Example 6

[0063] The preparation of the limonene essential oil Pickering emulsion was carried out according to the method described in Example 5, wherein the oil phase was limonene essential oil, N + MPAN + The prepared limonene essential oil Pickering emulsion, with an aqueous solution concentration of 0.5 mM, remained stable at room temperature for at least 6 months. After 6 months, observations were recorded using a digital camera and microscope. Figure 9 As shown, the emulsion remained stable and unchanged. This indicates that Pickering emulsion can encapsulate limonene essential oil, preventing direct contact with air, delaying its volatilization, and extending its shelf life. Limonene has excellent antibacterial, anti-inflammatory, anti-allergic, and antioxidant properties, and can play a good auxiliary role in repairing the skin barrier with long-term use.

[0064] Comparative Example 3

[0065] The method described in Example 6, wherein the oil phase is limonene essential oil and the aqueous phase is compound C12 -MPA-N + (to C) 12 The solution was prepared by homogenizing after passing CO2 through an MPA-N aqueous solution for 10 minutes. 12 -MPA-N aqueous solution requires CO2 to be bubbled through for 10 minutes to protonate and obtain C. 12 -MPA-N + (Aqueous solution) and 0.5 wt% nano silica, wherein C 12 -MPA-N + At an aqueous solution concentration of 0.5 mM, a stable Pickering emulsion was not obtained. The results indicate that, compared to compound C... 12 -MPA-N + Compound N + MPAN + The Pickering emulsification effect on limonene essential oil is more significant. 12 The structure of -MPA-N is Where n = 12.

Claims

1. A rosin-based, switchable CO2 / N2 responsive surfactant, characterized in that, Its molecular structure is:

2. The rosin-based, switchable CO2 / N2 responsive surfactant as described in claim 1, characterized in that: At room temperature, when CO2 is bubbled into an aqueous solution of NMPAN, the NMPAN will protonate and transform into N-cations within 30 seconds. + MPAN + Then to N + MPAN + When N2 is bubbled into an aqueous solution, the solution becomes turbid within 10 minutes. + MPAN + Deprotonation transforms the NMPAN back into NMPAN; the NMPAN response to CO2 / N2 is as follows:

3. The rosin-based, switchable CO2 / N2 responsive surfactant as described in claim 1 or 2, characterized in that: There are two abrupt change points in acid-base titration: pH=3.1 and pH=9.

2.

4. A method for preparing a rosin-based, switchable CO2 / N2 responsive surfactant according to any one of claims 1-3, characterized in that, It is prepared by a two-stage imidization reaction of maleic acridinium with N,N-dimethylethylenediamine.

5. The preparation method according to claim 4, characterized in that: Includes the following steps: S1, maleic acridin reacts with N,N-dimethylethylenediamine to form MPAN; S2 and MPAN undergo acyl chloride reaction with an acyl chloride reagent in an organic solvent, followed by imidization reaction with N,N-dimethylethylenediamine in an ice-water bath to generate NMPAN.

6. The preparation method according to claim 5, characterized in that: In step S1, the molar ratio of maleic acridinary acid to N,N-dimethylethylenediamine is 1:(1.0-1.5), anhydrous ethanol is used as solvent, the reaction temperature is 60-80℃, the reaction time is 4-6h, after the reaction is completed, the mixture is filtered and dried to obtain MPAN.

7. The preparation method according to claim 5, characterized in that: In step S2, the organic solvent is anhydrous dichloromethane, the acyl chloride reagent is oxalyl chloride, the molar ratio of MPAN to oxalyl chloride is 1:(1.5-2.0), the reaction temperature is 25-55℃, the reaction time is 3-6h, and the acyl chloride product is obtained by rotary evaporation; the molar ratio of the acyl chloride product to N,N-dimethylethylenediamine is 1:(1.0-1.2), dichloromethane is used as the solvent, the reaction temperature is 0-5℃, the reaction time is 2-4h, and NMPAN is obtained.

8. The use of a rosin-based, switchable CO2 / N2 responsive surfactant according to any one of claims 1-3, characterized in that: Used for the preparation of CO2 / N2 responsive Pickering emulsions, and / or for the encapsulation and sustained release of pharmaceuticals, and / or as a pH-responsive adsorbent.

9. The use as described in claim 8, characterized in that: The preparation method of CO2 / N2 responsive Pickering emulsion is as follows: 0.1-0.5 wt% nano-silica is dispersed in N... + MPAN + In an aqueous solution, equal volumes of aqueous and oil phases are subjected to high shear at 9000–12000 rpm for 1–5 min to obtain a CO2 / N2 responsive Pickering emulsion, which can remain stable for more than 6 months.

10. The use as described in claim 9, characterized in that: The oil phase is isooctane or limonene.

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