Amphiphilic cyclopeptide derivative and application thereof

Abstract

The invention discloses an amphiphilic cyclopeptide derivative and application thereof. The amphiphilic cyclopeptide derivative is shown as a formula II, and R1 and R2 are-OH; at least one of R1 and R2 is a novel amphiphilic organic molecule, the surface tension is low, the critical micelle concentration is low, the wetting reversal performance is excellent, and the amphiphilic cyclopeptide derivative can be widely applied as a surfactant. Particularly, the application includes but is not limited to use as an imbibition extraction agent and a composite displacement agent in the field of oil exploitation, the oil film stripping effect is good, the high temperature resistance, the high salt resistance and other properties are remarkably improved, and the oil recovery rate is high.

Description

Technical Field

[0001] This invention belongs to the fields of organic new molecule synthesis and petrochemical and chemical engineering technology, specifically relating to amphiphilic cyclic peptide derivatives and their applications. Background Technology

[0002] Amphiphilic cyclic peptides are a class of amphiphilic molecules containing hydrophobic fatty chains and hydrophilic cyclic peptide structures. This molecular structure endows them with unique physicochemical properties and biological activities. Typically, amphiphilic cyclic peptides exhibit surface tension below 30 mN / m and critical micelle concentration (CMC) below 50 mg / L, demonstrating extremely strong surface activity. Amphiphilic cyclic peptides can effectively reduce interfacial tension, enabling crude oil to form stable, low-viscosity emulsions, thereby improving oil recovery (Banat et al. 2010).

[0003] Due to the extremely harsh environment of underground oil reservoirs, especially unconventional ones, the fields of oil extraction demand surfactants with better thermal stability and salt tolerance, higher surface activity, lower interfacial tension and critical micelle concentration, better wetting reversal properties, and better biodegradability. Therefore, creating new organic molecules with superior surface activity, stability, and biodegradability by using existing amphiphilic cyclic peptide molecules as building blocks has significant scientific and practical value. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes an amphiphilic cyclic peptide derivative, a novel amphiphilic organic molecule with low surface tension, low critical micelle concentration, and excellent wetting reversal properties, making it widely applicable as a surfactant. Specifically, its uses include, but are not limited to, its use as a percolation extraction agent and composite displacement agent in the field of oil extraction, exhibiting good oil film stripping effect, significantly improved high-temperature and high-salt resistance, and high oil recovery rate.

[0005] In a first aspect, the present invention proposes an amphiphilic cyclic peptide derivative of Formula II.

[0006] in,

[0007] R1 and R2 are or -OH;

[0008] At least one of R1 and R2 is

[0009] According to an embodiment of the present invention, R1 and R2 are

[0010]

[0011] The amphiphilic cyclic peptide derivatives according to embodiments of the present invention exhibit low surface tension and low critical micelle concentration, enabling them to be widely used as surfactants. They also demonstrate excellent high-temperature and high-salt resistance, making them suitable for oil extraction applications, exhibiting good displacement and oil film removal effects, and resulting in high oil recovery rates. According to embodiments of the present invention, the amphiphilic cyclic peptide derivatives have one of the following structures:

[0012]

[0013]

[0014] In a second aspect, the present invention provides a surfactant. According to embodiments of the invention, it comprises: the aforementioned amphiphilic cyclic peptide derivative.

[0015] Those skilled in the art will understand that the features and advantages described above for the amphiphilic cyclic peptide derivatives shown in Formula II also apply to this surfactant, and will not be repeated here.

[0016] In a third aspect, the present invention provides an enhanced oil recovery (EOR) reagent. According to embodiments of the invention, it comprises either the aforementioned amphiphilic cyclic peptide derivative or the aforementioned surfactant. The EOR reagent according to embodiments of the present invention exhibits low surface tension, low critical micelle concentration, excellent wetting reversal properties, and strong resistance to high temperatures and high salt concentrations, enabling it to be used as a highly efficient surfactant in oil extraction to enhance oil recovery.

[0017] According to embodiments of the present invention, the reagent includes, but is not limited to: an adsorption extraction agent or a composite displacement agent.

[0018] In a fourth aspect, the present invention proposes the use of the aforementioned amphiphilic cyclic peptide derivatives or the aforementioned surfactants in the preparation of reagents for enhancing oil recovery.

[0019] According to embodiments of the present invention, the reagent includes, but is not limited to: an adsorption extraction agent or a composite displacement agent.

[0020] Those skilled in the art will understand that the features and advantages described above for the amphiphilic cyclic peptide derivatives of Formula II and the reagents for enhancing oil recovery are also applicable to this use, and will not be repeated here.

[0021] In a fifth aspect, the present invention proposes the application of the aforementioned amphiphilic cyclic peptide derivatives, surfactants, or enhanced oil recovery (EOR) reagents in oil extraction. The aforementioned amphiphilic cyclic peptide derivatives exhibit low surface tension, low critical micelle concentration, and excellent wetting reversal properties. As effective surfactant components in EOR reagents, they facilitate water wetting and penetration into the pores of the reservoir, thereby improving oil sweeping efficiency. They also promote oil droplet coalescence and flow, thus enhancing oil recovery. During tertiary oil recovery, the aforementioned amphiphilic cyclic peptide derivatives effectively clean crude oil from the reservoir rock surface, improving washing efficiency. Furthermore, the aforementioned amphiphilic cyclic peptide derivatives demonstrate strong resistance to high temperatures and salinity, excellent stress resistance, and strong adaptability to underground reservoir environments.

[0022] In a sixth aspect, the present invention provides a method for preparing the aforementioned amphiphilic cyclic peptide derivative. According to an embodiment of the present invention, the method includes: activating the amphiphilic cyclic peptide of Formula I with an activating agent to obtain an activated amphiphilic cyclic peptide; and subjecting the activated amphiphilic cyclic peptide to an acid-amine condensation reaction with lysine to obtain the amphiphilic cyclic peptide derivative.

[0023]

[0024] As is known to those skilled in the art, the reaction process and reaction products can be controlled by adjusting reaction conditions such as reaction time, temperature, and substrate molar equivalent.

[0025] According to embodiments of the present invention, the activator is selected from at least one of dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and dimethylaminopyridine. This further enhances the substrate activation, facilitating the acid-amine condensation reaction.

[0026] According to an embodiment of the present invention, the dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and dimethylaminopyridine can be used in combination.

[0027] In some optional embodiments of the present invention, the activator is composed of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of dicyclohexylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of diisopropylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and diisopropylcarbodiimide in a molar ratio of (1-2):(1-2), or of dicyclohexylcarbodiimide and diisopropylcarbodiimide in a molar ratio of (1-2):(1-2). This further improves the activation performance of the activator.

[0028] According to an embodiment of the present invention, in the activation treatment, the molar equivalent of the activator is 1 to 20 times, preferably 5 to 12 times, the molar equivalent of the amphiphilic cyclic peptide. This further enhances the activation effect of the amphiphilic cyclic peptide.

[0029] For example, the molar equivalent of the activator is 5, 6, 7, 8, 9, 10, 11, or 12 times the molar equivalent of the amphiphilic cyclic peptide.

[0030] According to an embodiment of the present invention, in the acid-amine condensation reaction, the molar equivalent of the amphiphilic cyclic peptide is 1 equivalent, and the molar equivalent of the lysine is 1 to 10 equivalents, preferably 2 to 6 equivalents. This further improves the reaction efficiency and product yield.

[0031] For example, the lysine molar equivalent is 2 equivalents, 2.5 equivalents, 3 equivalents, 3.5 equivalents, 4 equivalents, 4.5 equivalents, 5 equivalents, 5.5 equivalents, or 6 equivalents.

[0032] According to embodiments of the present invention, the activation treatment and / or the acid-amine condensation reaction are carried out in an organic solvent, preferably methanol, ethanol, N,N-dimethylformamide, or dimethyl sulfoxide.

[0033] According to an embodiment of the present invention, the reaction temperature of the activation treatment and / or the acid-amine condensation reaction is 20–45°C.

[0034] For example, the reaction temperature is 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃, 33℃, 34℃, 35℃, 36℃, 37℃, 38℃, 39℃, 40℃, 41℃, 42℃, 43℃, 44℃, or 45℃.

[0035] Compared with the prior art, the beneficial technical effects achieved by the present invention are as follows:

[0036] (1) The surface tension of the novel amphiphilic cyclic peptide molecule designed, obtained, and confirmed by this invention is significantly reduced. At low concentrations, the surface tension value of this novel amphiphilic cyclic peptide molecule is significantly lower than that of the unmodified amphiphilic cyclic peptide, the contact angle is less than 20°, and the critical micelle concentration is less than 20 mg / L. Therefore, the amphiphilicity of the novel amphiphilic cyclic peptide molecule of this invention is further enhanced.

[0037] (2) The amphiphilic cyclic peptide molecules of the present invention maintain their amphiphilic properties after undergoing high-temperature and high-salinity aging treatment, exhibiting superior surface activity and stress resistance. Therefore, the amphiphilic cyclic peptide molecules of the present invention possess improved high-temperature resistance and high-salinity resistance, demonstrating significant advantages in oilfield chemistry fields such as enhanced oil recovery and in adapting to harsh underground reservoir environments.

[0038] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0039] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0040] Figure 1 This is a simulation diagram of the surface electrostatic potential distribution of the new amphiphilic cyclic peptide molecule in Example 1 of the present invention;

[0041] Figure 2 ESI-MS image of the novel amphiphilic cyclic peptide molecule of Example 1 of this invention;

[0042] Figure 3 This is a sample morphology diagram of the new amphiphilic cyclic peptide molecule of Example 1 of the present invention;

[0043] Figure 4 This is a graph showing the surface tension values ​​of the new amphiphilic cyclic peptide molecule in Example 4 of the present invention.

[0044] Figure 5 The figure shows the results of the temperature resistance test of the new amphiphilic cyclic peptide molecule in Example 6 of the present invention;

[0045] Figure 6 This is a graph showing the results of the critical micelle concentration investigation of the new amphiphilic cyclic peptide molecule in Example 8 of the present invention;

[0046] Figure 7 This is a diagram showing the results of the microscopic displacement effect of the new amphiphilic cyclic peptide molecule in Example 9 of the present invention. Detailed Implementation

[0047] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0048] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0050] In this document, the terms “comprising” or “including” are open-ended expressions, meaning that they include the contents specified in this invention, but do not exclude other aspects.

[0051] In this document, the terms “optionally,” “optionally,” or “optionally” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0052] In this invention, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; unless otherwise stated, the values ​​of the parameters mentioned herein can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this invention).

[0053] Terms and Definitions

[0054] In this invention, the term "cyclic peptide" is equivalent to "cyclic polypeptide".

[0055] In this invention, the term "amphiphilic" is equivalent to "amphiphilic," referring to a molecule that simultaneously possesses hydrophilicity and lipophilicity (hydrophobicity). Such molecules typically contain a hydrophilic polar head and a hydrophobic nonpolar tail. "Amphiphilic cyclic peptide" is equivalent to "amphiphilic cyclic peptide," referring to a class of amphiphilic molecules containing a hydrophobic fatty chain and a hydrophilic cyclic peptide structure.

[0056] In this invention, the term "ambiphilic cyclic peptide derivative" is equivalent to "ambiphilic cyclic peptide novel molecule" in the context.

[0057] In this article, the term "dicyclohexylcarbodiimide" is equivalent to "Dicyclohexylcarbodiimide" or "DCC".

[0058] In this article, the term "diisopropylcarbodiimide" is equivalent to "Diisopropylcarbodiimide" or "DIC".

[0059] In this document, the term “1-(3-dimethylaminopropyl)-3-ethylcarbodiimide” is equivalent to “1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide” and “EDCI”.

[0060] In this article, the term "dimethylaminopyridine" is equivalent to "Dimethylaminopyridine" and "DMAP".

[0061] The unique physicochemical properties and biological activities of amphiphilic cyclic peptides are determined by their molecular structure. The amino acid composition and the properties of the amino acid side chain groups within the cyclic peptide have a significant impact on the amphiphilic cyclic peptide molecule. The design concept of this invention is to use molecular computational simulation to design a novel cyclic peptide structure with enhanced polarity (chemical structure shown in Formula II, hereinafter referred to as the "new amphiphilic cyclic peptide molecule"). Based on acid-amine condensation reactions, the carboxyl groups on the structure of the amphiphilic cyclic peptide (chemical structure shown in Formula I) are directionally modified to introduce groups with enhanced polarity, thereby altering the structural composition of the hydrophilic end of the cyclic peptide structure. This leads to the development of a method for preparing this new amphiphilic cyclic peptide molecule.

[0062] The inventors selected lysine as a modifier and, using molecular simulation calculations, determined the surface electrostatic potential, total molecular energy, dipole moment, and negative charge surface area ratio of the new amphiphilic cyclic peptide molecule. The molecular simulation calculation results of the amphiphilic cyclic peptide before and after lysine modification, as shown in Equation I, are illustrated in Table 1. Figure 1 As shown.

[0063] Table 1 shows the molecular simulation results of the amphiphilic cyclic peptide before and after modification, as shown in Equation I.

[0064]

[0065] The larger the dipole moment, the stronger the polarity of the molecule. This is determined by the total molecular energy and the proportion of negative charge surface area. Compared with the amphiphilic cyclic peptide shown in Formula I, the polarity of the new amphiphilic cyclic peptide molecule of the present invention is significantly enhanced.

[0066] Further experimental results show that, by modifying the amphiphilic cyclic peptide of Formula I with lysine via an acid-amine condensation reaction, a novel amphiphilic cyclic peptide molecule of the present invention (i.e., the amphiphilic cyclic peptide derivative of Formula II) can be obtained. The reaction involves an acid-amine condensation reaction between lysine as a modifier and the carboxyl group on the cyclic peptide structure of the amphiphilic cyclic peptide molecule shown in Formula I. At least one carboxyl group in the amphiphilic cyclic peptide molecule undergoes an acid-amine condensation reaction. As is known to those skilled in the art, the reaction process and reaction products can be controlled by adjusting reaction conditions such as reaction time, temperature, and substrate stoichiometry.

[0067] Further physicochemical property studies showed that the new amphiphilic cyclic peptide molecule exhibits significantly improved stability and amphiphilicity, making it suitable for widespread application as a surfactant. It also demonstrates high resistance to high temperatures and salts, making it ideal for oil extraction with good displacement and oil film removal effects, resulting in high oil recovery.

[0068] In some specific embodiments, amphiphilic cyclic peptide derivatives with both carboxyl sites modified are obtained by amidation modification of the first and second carboxyl groups of the amphiphilic cyclic peptide shown in Formula I. The synthetic route is shown below:

[0069]

[0070] In some specific implementations, the amphiphilic cyclic peptide shown in Formula I is dissolved in an organic solvent at 20–45°C, and then an activator is added to activate the first carboxyl group and / or the second carboxyl group, followed by the addition of lysine to carry out an acid-amine condensation reaction.

[0071] In some specific implementation schemes, the acid-amine condensation reaction time is not less than 7 hours.

[0072] In some specific implementations, the organic solvent is methanol, ethanol, N,N-dimethylformamide, or dimethyl sulfoxide.

[0073] In some specific embodiments, the activator is at least one of dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and dimethylaminopyridine.

[0074] In some specific implementations, the dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and dimethylaminopyridine can be used in combination.

[0075] In some optional embodiments of the present invention, the activator is composed of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of dicyclohexylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of diisopropylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and diisopropylcarbodiimide in a molar ratio of (1-2):(1-2), or of dicyclohexylcarbodiimide and diisopropylcarbodiimide in a molar ratio of (1-2):(1-2). This further improves the activation performance of the activator.

[0076] In some specific embodiments, the molar equivalent of the activator is 1 to 20 times, preferably 5 to 12 times, the molar equivalent of the amphiphilic cyclic peptide. This further enhances the activation effect of the amphiphilic cyclic peptide.

[0077] For example, the molar equivalent of the activator is 5, 6, 7, 8, 9, 10, 11, or 12 times the molar equivalent of the amphiphilic cyclic peptide.

[0078] In some specific embodiments, in the acid-amine condensation reaction, the molar equivalent of the amphiphilic cyclic peptide is 1 equivalent, and the molar equivalent of the lysine is 1 to 10 equivalents, preferably 2 to 6 equivalents. This further improves reaction efficiency and product yield.

[0079] For example, the lysine molar equivalent is 2 equivalents, 2.5 equivalents, 3 equivalents, 3.5 equivalents, 4 equivalents, 4.5 equivalents, 5 equivalents, 5.5 equivalents, or 6 equivalents.

[0080] In the embodiments of the present invention, unless otherwise specified, the amphiphilic cyclic peptide molecules shown in Formula I were prepared with reference to the following literature: Wang M, Yu H, Li X, et al. Single-gene regulated non-spore-forming Bacillus subtilis: Construction, transcriptome responses, and applications for producing enzymes and surfactin[J]. Metabolic Engineering, 2020, 62: 235-248.

[0081] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0082] Example 1: Synthesis and Identification of Novel Amphiphilic Cyclic Peptide Molecules

[0083] Weigh 20 mM of the amphiphilic cyclic peptide starting material and dissolve it in 20 mL of ethanol. After stirring and dissolving, add 180 mM 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI) and 180 mM p-dimethylaminopyridine (DMAP) and stir at 25 °C. Then add 4 equivalents of lysine and stir for at least 7 hours before terminating the reaction. Transfer the reaction solution to a centrifuge tube, centrifuge, and remove the ethanol solvent. Redissolve the peptide with an equal volume of aqueous solution, adjust the pH to strongly acidic conditions, sonicate for 20 min, centrifuge, and finally dry to obtain the new amphiphilic cyclic peptide molecule.

[0084] Characterization of the novel amphiphilic cyclic peptide molecule by ESI-MS ( Figure 2 ).like Figure 2 As shown: the compounds corresponding to the peaks of 1265.9 and 1279.56 are the new amphiphilic cyclic peptide molecules in this embodiment, in which both carboxyl sites are modified.

[0085] In the preparation method of this embodiment, the yield of the new amphiphilic cyclic peptide molecule is not less than 50%.

[0086] The physical sample of the new amphiphilic cyclic peptide prepared in this embodiment is shown below. Figure 3 As shown.

[0087] The synthetic route for the new amphiphilic cyclic peptide molecule in this embodiment is as follows:

[0088]

[0089] Example 2: Solvent determination for the acid-amine condensation reaction of a new amphiphilic cyclic peptide molecule.

[0090] Weigh 20 mM of the amphiphilic cyclic peptide starting material and dissolve it in 20 mL of a selected organic solvent (methanol, ethanol, N,N-dimethylformamide, dimethyl sulfoxide). After stirring and dissolving, add 180 mM 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI) and 180 mM p-dimethylaminopyridine (DMAP) and stir at 25 °C. Then add 4 equivalents of lysine and stir for at least 7 h to terminate the reaction. The differences between the organic solvents are shown in Table 2. Transfer the reaction solution to a centrifuge tube and remove the organic solvent after centrifugation. Redissolve the peptide with an equal volume of aqueous solution, adjust the pH to strongly acidic conditions, sonicate for 20 min, centrifuge, and finally dry to obtain the new amphiphilic cyclic peptide molecule.

[0091] The surface tension was measured as follows: The instrument used was a QBZY-2 fully automatic surface tension meter, based on the Wilhelmy Plate method. Surface tension was measured by bringing a platinum plate into contact with the surface of an aqueous solution containing a certain concentration of amphiphilic cyclic peptide agent (measurement range 0–400 N / m). The indoor temperature was 25 ± 2℃. At the start of the test, the surface tension of pure water was measured first, which was approximately 72 mN / m, designated as control group 1. Then, the surface tension of an aqueous solution with a mass concentration of 0.1% amphiphilic cyclic peptide agent was measured using the same method. Three parallel tests were conducted, and the average value was recorded as the final surface tension value of the aqueous solution at that concentration. The surface tension of the unmodified amphiphilic cyclic peptide molecule under the same conditions was measured to be 29.8 ± 0.5 mN / m, designated as control group 2.

[0092] The surface tensions of the new amphiphilic cyclic peptide molecules prepared by the inventors using different solvents are shown in Table 2.

[0093] Table 2. Surface tension of new amphiphilic cyclic peptide molecules prepared using different solvents.

[0094]

[0095]

[0096] In the selected organic solvents, acid-amine condensation reactions can occur, and the surface tension of the obtained new amphiphilic cyclic peptide molecules is better than that of the unmodified amphiphilic cyclic peptide molecules.

[0097] Example 3: Determination of activator for acid-amine condensation reaction of new amphiphilic cyclic peptide molecules

[0098] Weigh 20 mM of the amphiphilic cyclic peptide molecule and dissolve it in 20 mL of ethanol. After stirring and dissolving, add 180 mM of activators of different types and compositions, and then stir the reaction at 25 °C. Next, add 4 equivalents of lysine and stir the reaction for at least 7 hours before terminating the reaction. The differences between the activators are shown in Table 3. Transfer the reaction solution to a centrifuge tube, centrifuge, and remove the organic solvent. Redissolve the peptide with an equal volume of aqueous solution, adjust the pH to strongly acidic conditions, sonicate for 20 min, centrifuge, and finally dry to obtain the new amphiphilic cyclic peptide molecule.

[0099] The surface tension of the new amphiphilic cyclic peptide molecule was determined using the same method as in Example 2. Under the same conditions, the surface tension of the unmodified amphiphilic cyclic peptide molecule was measured to be 29.8 ± 0.5 mN / m, and this was designated as the control group S0.

[0100] The surface tensions of the new amphiphilic cyclic peptide molecules prepared by the inventors using different condensing agents are shown in Table 3.

[0101] Table 3. Surface tension of new amphiphilic cyclic peptide molecules prepared using different activators.

[0102]

[0103]

[0104] The results showed that: (1) compared with the unmodified amphiphilic cyclic peptide molecule, the surface tension of the modified amphiphilic cyclic peptide molecule was significantly reduced, exhibiting stronger surface activity; (2) the type and composition of the activator affected the surface tension value of the amphiphilic cyclic peptide molecule. When one or more of DCC, DIC, EDCI or DMAP were selected as the activator for the reaction, the surface tension value of the modified amphiphilic cyclic peptide molecule was significantly reduced compared with the unmodified amphiphilic cyclic peptide molecule, exhibiting stronger surface activity; among them, the combination of EDCI and DMAP resulted in the amphiphilic cyclic peptide molecule with the lowest surface tension value.

[0105] Example 4: Investigation of surface tension values ​​of novel amphiphilic cyclic peptide molecules

[0106] Following the optimal conditions of Example 3, a novel amphiphilic cyclic peptide molecule was prepared, and its surface tension value was then investigated. The specific investigation scheme is as follows:

[0107] The modified amphiphilic cyclic peptide molecules prepared in Example 3 and the unmodified amphiphilic cyclic peptide molecules were respectively prepared into aqueous solutions of amphiphilic cyclic peptide agent with a mass concentration of 0.1% using distilled water.

[0108] The instrument used for testing was a QBZY-2 fully automatic surface tension meter. Based on the Wilhelmy Plate method, surface tension was measured by bringing a platinum plate into contact with the surface of an aqueous solution containing a certain concentration of amphiphilic cyclic peptide agent (measurement range 0–400 N / m). The indoor temperature was 25 ± 2℃. Specific testing procedures are detailed in Example 2.

[0109] Test results: The surface tension of the modified amphiphilic cyclic peptide molecule was 16.6 ± 0.2 mN / m, while that of the unmodified amphiphilic cyclic peptide molecule was 29.8 ± 0.5 mN / m. Figure 4 ).

[0110] The results showed that, compared with the unmodified amphiphilic cyclic peptide, the modified amphiphilic cyclic peptide molecule exhibited a significantly lower surface tension and superior surface activity. Therefore, the new amphiphilic cyclic peptide molecule of this invention can be used to reduce oil-water interfacial tension and promote oil droplet aggregation and flow.

[0111] Example 5: Wettability Study of New Amphiphilic Cyclic Peptide Molecule

[0112] Following the optimal conditions of Example 3, a novel amphiphilic cyclic peptide molecule was prepared, and its wettability was then investigated. The specific investigation scheme is as follows:

[0113] Clean glass slides were placed in aging oil (shale oil XY4: kerosene: bitumen = 2:5:3) and aged at 60°C for more than one month. The wettability of the new amphiphilic cyclic peptide molecule was evaluated by measuring its contact angle.

[0114] The new amphiphilic cyclic peptide molecule prepared in Example 1 and the unmodified amphiphilic cyclic peptide molecule were respectively prepared into an aqueous solution of amphiphilic cyclic peptide agent with distilled water, with a mass concentration of 0.1%. Before the experiment, the aged glass slide was wiped with lint-free paper to remove excess crude oil from the surface, and then it was placed flat and immersed in the aqueous solution of amphiphilic cyclic peptide agent to be tested for 10 minutes, and then taken out and dried.

[0115] The contact angle was measured using an SCI6000E contact angle meter. For each test, a 2μL water droplet was dropped from the injection needle, and the contact angle at a stable state was obtained using the instrument's built-in camera and angle measurement software. To ensure the accuracy and reliability of the experimental results, each sample was tested at least three times, and the average of the contact angles obtained from multiple measurements was taken as the contact angle value of the analyte.

[0116] Test results: The contact angle of the modified amphiphilic cyclic peptide molecule was 15±0.5°, while the contact angle of the unmodified amphiphilic cyclic peptide molecule was 25±0.6°.

[0117] The results showed that, compared with the unmodified amphiphilic cyclic peptide, the modified amphiphilic cyclic peptide had a significantly reduced contact angle and exhibited excellent wetting reversal properties.

[0118] Example 6: High-Temperature Resistance of the New Amphiphilic Cyclic Peptide Molecule

[0119] Following the optimal conditions of Example 3, a novel amphiphilic cyclic peptide molecule was prepared, and its high-temperature resistance was then investigated. The specific investigation scheme is as follows:

[0120] The amphiphilic cyclic peptide sample obtained in Example 3 was placed in an oven at 121°C for 100 min and then prepared into a working solution with a mass concentration of 0.1% using distilled water. The surface tension of the aqueous solution at 25±2°C was tested, and the specific test steps were as described in Example 2.

[0121] Using this method, the surface tension of the new amphiphilic cyclic peptide molecule was 16.6 mN / m, and after high-temperature treatment, its surface tension decreased to 16.5 mN / m. The surface tension of the new amphiphilic cyclic peptide molecule did not change significantly before and after high-temperature treatment, indicating that it can withstand 120℃ (…). Figure 5 ).

[0122] This result indicates that the modified amphiphilic cyclic peptide molecule has high-temperature resistance.

[0123] Example 7: Investigation of the high-mineral resistance of the new amphiphilic cyclic peptide molecule

[0124] Following the optimal conditions of Example 3, a novel amphiphilic cyclic peptide molecule was prepared, and its resistance to high mineral content was then investigated. The specific investigation scheme is as follows:

[0125] The amphiphilic cyclic peptide molecule sample obtained in Example 3 and the unmodified amphiphilic cyclic peptide molecule were respectively prepared into working solutions with a mass concentration of 0.1% by using saline solution with a concentration of 100 g / L. The surface tension value of the aqueous solution at 25±2℃ was tested. The specific test steps are as described in Example 2.

[0126] Using this method, the surface tension of the new amphiphilic cyclic peptide molecule was as low as 24 mN / m, and its mineralization was ≥1×10⁻⁶. 5 mg / L; the surface tension of the unmodified amphiphilic cyclic peptide molecule is 37.1±0.8 mN / m, and the mineralization is less than 1×10 mg / L. 5 mg / L.

[0127] These results indicate that the modified amphiphilic cyclic peptide has improved high-salt resistance compared to the unmodified amphiphilic cyclic peptide.

[0128] Example 8: Investigation of the critical micelle concentration of a novel amphiphilic cyclic peptide molecule

[0129] Following the optimal conditions of Example 3, a novel amphiphilic cyclic peptide molecule was prepared, and its critical micelle concentration was then investigated. The specific investigation scheme is as follows:

[0130] The modified amphiphilic cyclic peptide molecules prepared in Example 3 and the unmodified amphiphilic cyclic peptide molecules were respectively prepared into aqueous solutions with concentrations of 5 mg / L, 10 mg / L, 15 mg / L, 20 mg / L, 25 mg / L, 30 mg / L, 35 mg / L, 40 mg / L, 45 mg / L, and 50 mg / L using distilled water. Surface tension was measured using a QBZY-2 fully automatic surface tension meter based on the platinum plate method, at an indoor temperature of 25 ± 2 °C. Initially, the surface tension of pure water was measured, which was approximately 72 mN / m. Then, the solution concentration was measured from low to high to obtain the surface tension at different concentrations. The relationship curve between surface tension and solution concentration was obtained after the test.

[0131] Using this assay, the critical micelle concentration of the novel amphiphilic cyclic peptide molecule was below 20 mg / L, while the critical micelle concentration of the unmodified amphiphilic cyclic peptide molecule exceeded 25 mg / L. Figure 6 ).

[0132] The above results indicate that the prepared amphiphilic cyclic peptide molecule has typical surface activity and can significantly reduce the surface tension of aqueous solutions.

[0133] Example 9: Investigation of the microscopic displacement effect of novel amphiphilic cyclic peptide molecules

[0134] Following the optimal conditions of Example 3, a novel amphiphilic cyclic peptide molecule was prepared, and its microscopic displacement effect was then investigated. The specific investigation scheme is as follows:

[0135] (1) Add saturated simulated oil (200 mPa·s) to the micro model, heat at 90°C and let stand for 24 hours to age;

[0136] (2) Fix the experimental setup and start water driving at an injection rate of 50 μL / min for 5 min.

[0137] (3) The modified amphiphilic cyclic peptide molecules prepared in Example 3 and the unmodified amphiphilic cyclic peptide molecules were used to start the displacement, with an injection rate of 20 μL / min and a displacement time of 30 min.

[0138] (4) After standing for 12 hours, continue to use the modified amphiphilic cyclic peptide molecules and the unmodified amphiphilic cyclic peptide molecules for displacement at an injection rate of 100 μL / min for 15 min.

[0139] Image binarization analysis is used. The image is then input into MATLAB to calculate the area of ​​the oil phase, thus deriving the percentage, i.e., the recovered area (blank portion of the image) / total area × 100%. This is used to calculate the microrecovery rate of the oil. Figure 7 ).

[0140] Using this assay, the recovery rate of unmodified amphiphilic cyclic peptide molecules was 45.1%, while the recovery rate of modified amphiphilic cyclic peptide molecules was 58.1%, representing a 13% increase in recovery rate and good oil film stripping effect.

[0141] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. The amphiphilic cyclic peptide derivative shown in Formula II, in, R1 and R2 are or -OH; At least one of R1 and R2 is 2. The amphiphilic cyclic peptide derivative according to claim 1, characterized in that, R1 and R2 are 3. The amphiphilic cyclic peptide derivative according to claim 1, characterized in that, The amphiphilic cyclic peptide derivative has one of the following structures:

4. A surfactant, characterized in that, include: The amphiphilic cyclic peptide derivative according to any one of claims 1 to 3.

5. A reagent for enhancing oil recovery, characterized in that, include: The amphiphilic cyclic peptide derivative according to any one of claims 1 to 3 or the surfactant according to claim 4; Optionally, the reagents include, but are not limited to: percolation extraction agents or composite displacement agents.

6. Use of the amphiphilic cyclic peptide derivative according to any one of claims 1 to 3 and the surfactant according to claim 4 in the preparation of reagents for enhancing oil recovery; Optionally, the reagents include, but are not limited to: percolation extraction agents or composite displacement agents.

7. The application of the amphiphilic cyclic peptide derivative according to any one of claims 1 to 3, the surfactant according to claim 4, or the oil recovery enhancer according to claim 5 in oil extraction.

8. A method for preparing the amphiphilic cyclic peptide derivative according to any one of claims 1 to 3, characterized in that, include: The amphiphilic cyclic peptide shown in Formula I is activated by an activator to obtain the activated amphiphilic cyclic peptide. The activated amphiphilic cyclic peptide was subjected to an acid-amine condensation reaction with lysine to obtain the amphiphilic cyclic peptide derivative.

9. The method according to claim 8, characterized in that, The activator is selected from at least one of dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and dimethylaminopyridine; Furthermore, the activator is selected from two of the following: dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and dimethylaminopyridine; Optionally, the activator is composed of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of dicyclohexylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of diisopropylcarbodiimide and dimethylaminopyridine in a molar ratio of (1-2):(2-1), or of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and diisopropylcarbodiimide in a molar ratio of (1-2):(1-2), or of dicyclohexylcarbodiimide and diisopropylcarbodiimide in a molar ratio of (1-2):(1-2); Optionally, in the activation treatment, the molar equivalent of the activator is 1 to 20 times, preferably 5 to 12 times, the molar equivalent of the amphiphilic cyclic peptide; Optionally, in the acid-amine condensation reaction, the molar equivalent of the amphiphilic cyclic peptide is 1 equivalent, and the molar equivalent of the lysine is 1 to 10 equivalents, preferably 2 to 6 equivalents; Furthermore, the activation treatment and / or the acid-amine condensation reaction are carried out in an organic solvent; Optionally, the organic solvent is preferably methanol, ethanol, N,N-dimethylformamide, or dimethyl sulfoxide; Furthermore, the reaction temperature for the activation treatment and / or the acid-amine condensation reaction is 20–45°C.

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