Supramolecular surfactant as well as preparation method and application thereof

Abstract

The invention relates to a supramolecular surfactant and a preparation method and application thereof, the supramolecular surfactant is obtained by a hydrophobic host molecule and a hydrophilic guest molecule through host-guest complexation, the hydrophobic host molecule is a hydrophobic cyclodextrin compound, and the hydrophilic guest molecule is a hydrophilic cyclodextrin compound. The hydrophilic guest molecules comprise at least one of methyl orange and hydrophilic derivatives thereof. The surfactant has excellent hydrophilicity and foam performance, is good in stability, and can effectively improve the thickened oil recovery efficiency when being used in thickened oil recovery.

Description

Technical Field

[0001] This disclosure relates to a supramolecular surfactant, its preparation method, and its application. Background Technology

[0002] One method for extracting heavy oil is conventional water injection. Due to the high viscosity and low mobility of heavy oil, compared to the high mobility of water, the water-to-oil mobility ratio is high during waterflooding. This leads to the displacing fluid easily penetrating the oil phase, resulting in a low sweep area, a small area for heavy oil mobilization, and low oil displacement efficiency. Implementing chemical flooding on top of waterflooding can effectively improve the displacement effect. Surfactants have wetting-improving properties, reversing the wetting of the oil-wetted wellbore and tubing to water wetting, reducing flow friction. During surfactant flooding, surfactants have emulsifying and dispersing effects, emulsifying and dispersing heavy oil into an O / W emulsion with an aqueous phase, reducing viscosity. Simultaneously, surfactants also have wetting-improving effects, preventing oil droplets from re-adsorbing onto the rock surface and enhancing the fluidity of the emulsified heavy oil in low-porosity environments. However, existing surfactants still have drawbacks such as insufficient foaming properties, unstable foaming, or insufficient hydrophilicity, which adversely affect extraction efficiency when used in heavy oil extraction. Summary of the Invention

[0003] The purpose of this disclosure is to provide a supramolecular surfactant, its preparation method, and its application to enhance the surface activity properties of surfactants.

[0004] To achieve the above objectives, the first aspect of this disclosure provides a supramolecular surfactant, wherein the supramolecular surfactant is obtained by a host-guest complexation of a hydrophobic host molecule and a hydrophilic guest molecule, wherein the hydrophobic host molecule is a hydrophobic cyclodextrin compound, and the hydrophilic guest molecule includes at least one of methyl orange and its hydrophilic derivatives.

[0005] Optionally, the hydrophobic cyclodextrin compound has a structure as shown in general formula (1): (1) In formula (1), R is selected from C4 to C14 alkyl groups, and n is 5 to 7.

[0006] Optionally, the hydrophilic guest molecule includes at least one of methyl orange, ethyl orange, and orange IV.

[0007] Optionally, the molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule is (1~3):1.

[0008] Optionally, the molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule is (1~2):1.

[0009] A second aspect of this disclosure provides a method for preparing a supramolecular surfactant, the method comprising: In the presence of a solvent, a hydrophobic host molecule is brought into contact with a hydrophilic guest molecule and a host-guest complexation reaction is carried out to obtain a supramolecular surfactant. The hydrophobic host molecule is a hydrophobic cyclodextrin compound, and the hydrophilic guest molecule includes at least one of methyl orange and its hydrophilic derivatives.

[0010] Optionally, the molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule is (1~3):1.

[0011] Optionally, the weight ratio of the hydrophobic host molecule to the solvent is 1:(100~200). The solvent includes at least one of water, methanol, N,N-dimethylformamide, and dimethyl sulfoxide.

[0012] A third aspect of this disclosure provides a supramolecular surfactant prepared by the method described in the second aspect of this disclosure.

[0013] This disclosure provides a fourth aspect, which provides the application of the supramolecular surfactants described in the first and third aspects of this disclosure in heavy oil extraction.

[0014] Through the above technical solution, this disclosure uses hydrophobic cyclodextrin compounds as the host molecule and methyl orange or its hydrophilic derivatives as the guest molecule. The two can be combined through host-guest complexation to obtain a supramolecular surfactant. This surfactant has excellent hydrophilicity and foaming properties, and good stability. When used in heavy oil extraction, it can effectively improve the efficiency of heavy oil extraction.

[0015] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a comparison of the proton NMR spectra of the supramolecular surfactant and methyl orange from Example 1. Detailed Implementation

[0017] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0018] In a first aspect, this disclosure provides a supramolecular surfactant, wherein the supramolecular surfactant is obtained by a host-guest complexation of a hydrophobic host molecule and a hydrophilic guest molecule, wherein the hydrophobic host molecule is a hydrophobic cyclodextrin compound, and the hydrophilic guest molecule includes at least one of methyl orange and its hydrophilic derivatives.

[0019] According to this disclosure, the hydrophobic host molecule is a hydrophobic cyclodextrin compound. Cyclodextrin compounds are bio-based raw materials and have the advantages of being green, pollution-free, and low-cost. The hydrophobic cyclodextrin compound can be alkylated cyclodextrin, alkoxylated cyclodextrin, etc. In one specific embodiment, the hydrophobic cyclodextrin compound has a structure as shown in general formula (1): (1), In formula (1), R is selected from C4 to C14 alkyl groups, preferably butane, decane, dodecane, and tetradecane, and n is 5 to 7.

[0020] In one specific embodiment, the hydrophobic cyclodextrin compound may include at least one of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin modified with C4-C14 chains. The hydrophobic cyclodextrin compound may be a commercially available product or prepared using methods in the prior art.

[0021] In one specific embodiment, the hydrophilic guest molecule includes at least one of methyl orange, ethyl orange, and orange-yellow IV. The chemical formula of methyl orange (i.e., sodium p-dimethylaminoazobenzenesulfonate) is C0. 14 H 14 N3NaO3S, CAS number 547-58-0; the chemical formula of ethyl orange is C 14 H 18 N3O3S, CAS number 13545-67-0; Orange IV chemical formula is C 18 H 14 N3NaO3S, CAS number 554-73-4.

[0022] According to this disclosure, the ratio of the hydrophobic host molecule to the hydrophilic guest molecule can be adjusted within a certain range. Specifically, the molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule can be (1~3):1, preferably (1~2):1.

[0023] In this disclosure, the hydrophobic host molecule and the hydrophilic guest molecule are bonded through host-guest complexation, wherein the host-guest complexation is a non-covalent interaction (such as hydrogen bonding, van der Waals forces, etc.), which has the advantages of simple preparation and high efficiency compared to surfactants modified by covalent interaction. The supramolecular surfactant of this disclosure has simple raw materials, is environmentally friendly, and has strong salt resistance. In particular, it exhibits excellent hydrophilicity and foaming properties, and its complexation properties are not affected by external environmental factors (such as light), and it has good stability.

[0024] A second aspect of this disclosure provides a method for preparing a supramolecular surfactant as described in the first aspect of this disclosure. The method includes: contacting a hydrophobic host molecule with a hydrophilic guest molecule in the presence of a solvent and obtaining a supramolecular surfactant through host-guest complexation; wherein the hydrophobic host molecule is a hydrophobic cyclodextrin compound, and the hydrophilic guest molecule includes at least one of methyl orange and its hydrophilic derivatives.

[0025] According to this disclosure, the hydrophobic host molecule and the hydrophilic guest molecule are consistent with those described in the first aspect of this disclosure. The molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule can be (1~3):1, preferably (1~2):1.

[0026] The solvent may include at least one of water, methanol, and N,N-dimethylformamide and dimethyl sulfoxide. The weight ratio of the hydrophobic host molecule to the first solvent may be 1:(100~200), preferably 1:(100~150). To improve the complexation effect, the contact between the hydrophobic host molecule and the hydrophilic guest molecule can be carried out by common mixing methods, such as stirring, stirring followed by standing, or ultrasonic dissolution.

[0027] In a third aspect, this disclosure provides supramolecular surfactants prepared by the methods described in the second aspect of this disclosure. The supramolecular surfactants prepared by the methods of this disclosure have advantages such as green raw material sources, simple and efficient preparation methods, low cost, mild reaction conditions, and strong safety. They are easy to scale up industrially and have promising prospects for widespread application. In particular, they exhibit excellent hydrophilicity and foaming properties, and good stability, making them suitable for heavy oil extraction and beneficial for improving heavy oil extraction efficiency.

[0028] This disclosure provides a fourth aspect, which provides the application of the supramolecular surfactants described in the first and third aspects of this disclosure in heavy oil extraction.

[0029] Specifically, the application may include: emulsifying a supramolecular surfactant solution with heavy oil under stirring conditions. The volume ratio of the supramolecular surfactant solution to the heavy oil may be (2~4):1; the concentration of the supramolecular surfactant solution may be 0.1% by weight; and the stirring conditions may include a rotation speed of 600~1000 rpm.

[0030] Using the supramolecular surfactant disclosed herein for heavy oil extraction is beneficial for reducing the viscosity of heavy oil, improving its fluidity, promoting its dispersion and emulsification, and is not easily deactivated by external environmental influences. It can maintain its stability in the complex environment of heavy oil extraction, is not easily hydrolyzed, oxidized or degraded, and can play a long-term and effective role, thus effectively improving the extraction efficiency of heavy oil.

[0031] The present disclosure is described in detail below through embodiments. In the following embodiments, unless otherwise specified, the instruments, reagents, materials, etc. involved are all conventional instruments, reagents, materials, etc., already existing in the prior art and obtainable through legitimate commercial channels.

[0032] The preparation method of dodecyl-modified α-cyclodextrin is as follows: weigh... α 10 mmol of α-cyclodextrin and 70 mmol of 1,2-epoxydodecane were added to a reaction flask, followed by 20 mL of water, 0.05 mmol of 4-dimethylaminopyridine, and a magnetic stir bar. The reaction system was stirred at 85 °C for 7 hours. The reaction was then stopped, filtered, and dried to obtain dodecyl-modified α-cyclodextrin.

[0033] Example 1 The hydrophilic guest molecule in this embodiment is methyl orange (purchased from Alfa, trade number 017874, structural formula: [insert structural formula here]). ), which is a hydrophobic host molecule modified with dodecyl α-cyclodextrin.

[0034] The hydrophobic host molecule and hydrophilic guest molecule are mixed with water, wherein the molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule is 1:1 and the weight ratio of the hydrophobic host molecule to water is 1:100. The host-guest complexation is carried out under stirring conditions to obtain a supramolecular surfactant.

[0035] The supramolecular surfactant was characterized by 1H NMR, with the 1H NMR spectrum of methyl orange used as a control. The results are as follows: Figure 1 As shown, Figure 1 The upper middle spectrum is the 1H NMR spectrum of the supramolecular surfactant prepared in this embodiment, and the lower spectrum is the 1H NMR spectrum of methyl orange. It can be seen that the supramolecular surfactant prepared in this embodiment is in the azobenzene aromatic region (chemical shift 7.77~7.71). Figure 1The signal at the middle arrow shows obvious chemical shift changes and peak splitting, indicating that the host molecule and the guest molecule have undergone complexation.

[0036] Example 2 Supramolecular surfactants were prepared according to the method in Example 1, except that the molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule was 3:1. The obtained supramolecular surfactants were characterized by 1H NMR spectroscopy, and the results were consistent with... Figure 1 similar.

[0037] Comparative Example 1 The hydrophilic guest molecule from Example 1 was prepared into an aqueous solution with a concentration of 2.2 mg / mL, which served as the surfactant in this comparative example.

[0038] Comparative Example 2 The hydrophobic host molecule from Example 1 was prepared into an aqueous solution with a concentration of 7.8 mg / mL, which was used as the surfactant in this comparative example.

[0039] Test case The surface activity properties of the surfactants in the test examples and comparative examples were tested, wherein the surfactants in the examples were prepared as aqueous solutions with a concentration of 10 mg / mL.

[0040] The test method was as follows: the surface tension of the mixed solution at the critical micelle concentration was tested using a Kruss 100 surface tension meter according to the step dilution method. The results are shown in Table 1.

[0041] Table 1

[0042] As can be seen from Table 1, the surfactants prepared in the examples have lower surface tension and exhibit excellent surface activity properties.

[0043] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0044] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0045] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A supramolecular surfactant, characterized in that, The supramolecular surfactant is obtained by a host-guest complexation of a hydrophobic host molecule and a hydrophilic guest molecule, wherein the hydrophobic host molecule is a hydrophobic cyclodextrin compound, and the hydrophilic guest molecule includes at least one of methyl orange and its hydrophilic derivatives.

2. The supramolecular surfactant according to claim 1, wherein, The hydrophobic cyclodextrin compounds have the structure shown in general formula (1): （1） In formula (1), R is selected from C4 to C14 alkyl groups, and n is 5 to 7.

3. The supramolecular surfactant according to claim 1, wherein, The hydrophilic guest molecule includes at least one of methyl orange, ethyl orange, and orange IV.

4. The supramolecular surfactant according to claim 1, wherein, The molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule is (1~3):

1.

5. The supramolecular surfactant according to claim 4, wherein, The molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule is (1~2):

1.

6. A method for preparing a supramolecular surfactant, characterized in that, The method includes: In the presence of a solvent, a hydrophobic host molecule is brought into contact with a hydrophilic guest molecule and a host-guest complexation reaction is carried out to obtain a supramolecular surfactant. The hydrophobic host molecule is a hydrophobic cyclodextrin compound, and the hydrophilic guest molecule includes at least one of methyl orange and its hydrophilic derivatives.

7. The method according to claim 6, wherein, The molar ratio of the hydrophobic host molecule to the hydrophilic guest molecule is (1~3):

1.

8. The method according to claim 6, wherein, The weight ratio of the hydrophobic host molecule to the solvent is 1:(100-200). The solvent includes at least one of water, methanol, N,N-dimethylformamide, and dimethyl sulfoxide.

9. A supramolecular surfactant prepared by the method according to any one of claims 6 to 8.

10. The application of the supramolecular surfactant according to any one of claims 1 to 5 and 9 in heavy oil extraction.

Images