Gemini benzenesulfonic acid ionic liquid surfactant as well as preparation method and application thereof

Abstract

The invention discloses a gemini benzenesulfonic acid ionic liquid surfactant and a preparation method and application thereof.The preparation method comprises the following steps that 1, 1 part of fatty acid, 2-4 parts of EDC or DCC and a proper amount of solvent are mixed to be uniform, a mixed solution is obtained, 0.2-0.8 part of 4, 4 '-diaminostilbene-2, 2'-disulfonic acid is dropwise added into the mixed solution, and the mixture is stirred to be uniform; then reacting for a period of time at a certain temperature to obtain a reaction solution, and then post-treating the reaction solution to obtain gemini fatty acid amide benzene sulfonic acid; and (2) mixing the gemini fatty acid amide benzenesulfonic acid prepared in the step (1), alkali and a solvent, stirring at room temperature for a period of time to obtain a reaction solution, and then carrying out rotary evaporation on the reaction solution to remove the solvent to obtain the gemini benzenesulfonic acid ionic liquid surfactant. The preparation method has the characteristics of simple preparation process, excellent oil-water interfacial tension reduction performance, high temperature resistance, excellent water solubility, wide application range and the like.

Description

Technical Field

[0001] The present invention belongs to the field of oilfield chemistry, relates to a surfactant, and particularly relates to a gemini benzenesulfonic acid-based ionic liquid surfactant, a preparation method thereof, and an application thereof. Background Technique

[0002] A surfactant is an amphiphilic molecule composed of a hydrophilic head and a hydrophobic tail. It can self-assemble into various aggregate structures in an aqueous solution, showing unique physical and chemical properties, and is widely used in fields such as washing, food, medicine, coatings, etc., especially in the field of oil and gas development, where it has obtained significant applications.

[0003] The surfactants commonly used in oil and gas development can be divided into non-ionic, cationic, betaine-type, etc. Among them, non-ionic surfactants have a wide range of salt tolerance and can withstand a salinity of up to 105 mg / L, but have poor temperature resistance and are prone to flocculation and precipitation failure when the temperature is higher than 65°C.

[0004] Cationic surfactants have excellent salt tolerance. For example, Chinese Patent Application CN114524736A discloses an asymmetric Gemini cationic surfactant and a preparation method thereof. This surfactant is a novel surfactant with a tricyclic diterpene structure, which is obtained by subjecting N,N-dimethyl long-chain fatty amine and epichlorohydrin to ring-opening reactions to obtain intermediates respectively, and then reacting and purifying the intermediates with dehydroabietylamine respectively. Chinese Patent Application CN105013390A discloses the application of the cationic surfactant described in Formula I as an adsorption sacrificial agent in reducing the adsorption amount of polymers used in oilfield flooding. The polymer is a hydrophobically associating polymer, and the cationic surfactant described in Formula I can form a strong adsorption with negatively charged reservoir minerals; at the same time, it can also form an electrostatic repulsion with the cationic hydrophobic group of the hydrophobically associating polymer to weaken its interaction with the polymer, ultimately achieving the purpose of isolating the polymer from the reservoir and reducing the adsorption amount of the polymer; at the same time, it can significantly reduce the polymer adsorption amount at a low concentration, saving the use cost of the polymer.

[0005] Betaine-type surfactants have excellent temperature and salt tolerance. For example, Chinese Patent Application CN110847870A discloses a method for improving the oil displacement efficiency in medium- and low-water-cut oilfields. The crude oil in medium- and low-water-cut oilfields is subjected to oil displacement and recovery using a cocamidopropyl betaine solution. The method for medium- and low-water-cut oilfields includes the following steps: Step 1, preparation of the cocamidopropyl betaine solution; Step 2, preparation work before injecting the cocamidopropyl betaine solution into the oil well; Step 3, injecting the cocamidopropyl betaine solution into the oil well; Step 4, injecting clear water in the forward direction to drive and cover the cocamidopropyl betaine solution to the oil displacement area, and shutting in the well for waiting for setting; Step 5, alternately injecting clear water in the forward and reverse directions. After multiple cycles, backwash the oil displacement well to make the water quality at the inlet and outlet consistent; Step 6, test the water absorption profile of the oil well; Step 7, repeat the above Steps 2 to 6 in sequence. After multiple cycles until the crude oil in the oil well is completely recovered. Chinese Patent Application CN104559989A discloses a hydrocarbon-based amine polyoxyethylene ether polyoxypropylene ether sulfonate-type betaine surfactant, its preparation method and its application in oilfield oil displacement. The present invention adopts a hydrocarbon-based amine polyoxyethylene ether polyoxypropylene ether sulfonate-type surfactant shown by the following formula, wherein R is a hydrocarbon group with C8-C40, and R1 and R2 are independently selected from C1-C4 alkylene groups. The technical solution of this invention patent application can present excellent oil displacement effect at high temperature and high salinity.

[0006] However, both of the above two surfactants have some deficiencies: 1. When a cationic surfactant is used for oil displacement, its cationic component is easily adsorbed by the reservoir and becomes ineffective; 2. Betaine-type has excellent high-temperature resistance and good interfacial activity in a relatively wide pH range, but betaine zwitterionic surfactants have a relatively high Krafft point and must be dissolved well at a relatively high temperature or a certain salinity. It is easy to precipitate during surface liquid preparation, which affects the effect. Therefore, there is an urgent need to develop a surfactant that simultaneously has high temperature resistance, low interfacial tension, is easily soluble in water, is not easily adsorbed, and has controllable cost and is easy to promote and apply.

[0007] Ionic liquids refer to liquids composed entirely of ions. Ionic liquids have good thermal stability and chemical stability and can be recycled. Summary of the Invention

[0008] Object of the Invention: Aiming at the deficiencies existing in the above-mentioned prior art, the present invention provides a gemini-type benzenesulfonic acid-based ionic liquid surfactant and its preparation method and application. The present invention has the following advantages: 1. It has the advantages of simple preparation process and easy synthesis, and can be widely used industrially; 2. The ionic liquid obtained by the method of the present invention has adjustable structure and wide application range; 3. High temperature resistance; 4. Low interfacial tension; 5. Easily soluble in water and not easily adsorbed.

[0009] Technical Solution: A gemini-type benzenesulfonic acid-based ionic liquid surfactant, whose structural formula is shown in Formula (1):

[0010]

[0011] Wherein: R is a straight-chain alkyl group with 12-24 carbon atoms;

[0012] M is an organic cation.

[0013] Further, the organic cation is one of benzyltrimethyl quaternary ammonium salt cation, dimethyl hydroxyethyl quaternary ammonium salt cation, trimethyl quaternary ammonium salt cation, amidine quaternary ammonium salt cation, imidazole quaternary ammonium salt cation, NH 4 + , and pyridine quaternary ammonium salt cation.

[0014] The preparation method of the above-mentioned gemini benzenesulfonic acid-based ionic liquid surfactant is as follows in terms of mole parts:

[0015] (1) Mix 1 part of fatty acid, 2-4 parts of EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide) or DCC (dicyclohexylcarbodiimide), and an appropriate amount of solvent evenly to obtain a mixed solution. Then, drop 0.2-0.8 part of 4,4'-diaminostilbene-2,2'-disulfonic acid into the mixed solution, and react at a certain temperature for a period of time to obtain a reaction solution. After post-treatment of the reaction solution, gemini fatty acid amide benzenesulfonic acid is obtained;

[0016] (2) Mix the gemini fatty acid amide benzenesulfonic acid prepared in step (1), alkali, and solvent, stir at room temperature for a period of time to obtain a reaction solution, and then rotary evaporate the reaction solution to remove the solvent to obtain the gemini benzenesulfonic acid-based ionic liquid surfactant.

[0017] Further, the general formula of the fatty acid in step (1) is as follows:

[0018] R-COOH, wherein: R is a straight-chain alkyl group with 12-24 carbon atoms.

[0019] Further, the solvent in step (1) is one of dimethyl sulfoxide, N,N-dimethylformamide, dichloromethane, ethanol, and methanol.

[0020] Further, the amount of the solvent in step (1) is at least 30 parts, preferably 30-100 parts.

[0021] Further, the reaction temperature in step (1) is 40-100 °C, and the reaction time is at least 2 h, preferably 2-10 h.

[0022] Further, the post-treatment in step (1) is: first rotary evaporation, and then drying.

[0023] Further, the base in step (2) is one of triethylamine, benzyltrimethylammonium, ammonia water, benzyltrimethylammonium hydroxide, choline hydroxide, and tetramethylammonium hydroxide.

[0024] Further, the stirring time in step (2) is at least 1 h, preferably 1 - 8 h.

[0025] Further, the solvent in step (2) is one of dimethyl sulfoxide, N,N-dimethylformamide, dichloromethane, ethanol, and methanol.

[0026] Further, the molar ratio of gemini fatty acid amide benzenesulfonic acid, base, and solvent in step (2) is 1:(2 - 3):(30 - 100).

[0027] The gemini benzenesulfonic acid-based ionic liquid surfactant is prepared by the preparation method described in any one of the above.

[0028] The application of the gemini benzenesulfonic acid-based ionic liquid surfactant described in any one of the above as an oil displacement agent in oil exploitation.

[0029] For the ionic liquid-based surfactant, the inorganic counterion in the traditional displacement agent is replaced by an organic ion in its molecular structure, which improves the interfacial activity and endows it with high-temperature resistance characteristics; based on the hydrophobic end association effect, the molecular structure can enhance the oil-water amphiphilicity and endow it with low interfacial tension characteristics, and the cationic and anionic groups in its structure endow it with excellent water solubility. Therefore, for the gemini benzenesulfonic acid-based ionic liquid surfactant, the association effect of its alkyl chain and benzene ring structure can strengthen the affinity with the oil phase and reduce the interfacial tension, the π-π stacking effect of the aromatic conjugate structure can inhibit the adsorption on the reservoir, the sulfonic acid head group and the organic cation pair can improve the high-temperature resistance performance, and endow excellent water solubility, and it is expected to meet the functional requirements of surfactants for oil and gas development.

[0030] Beneficial effects: A gemini benzenesulfonic acid-based ionic liquid surfactant and its preparation method and application disclosed by the present invention have the following beneficial effects:

[0031] 1. The gemini benzenesulfonic acid-based ionic liquid surfactant disclosed by the present invention can be rapidly dissolved at room temperature without any co-solvent, which is convenient for on-site preparation and has simple operation;

[0032] 2. The gemini benzenesulfonic acid-based ionic liquid surfactant described in the present invention can obtain an ultra-low interfacial tension at a relatively low concentration without any additives, is not easily adsorbed, and has controllable costs;

[0033] 3. The gemini benzenesulfonic acid-based ionic liquid surfactant described in the present invention can undergo self-emulsification phenomenon, improving the oil displacement efficiency;

[0034] 4. High temperature resistance. Description of the Drawings

[0035] Figure 1 This is a flow chart of a preparation method of a gemini benzenesulfonic acid-based ionic liquid surfactant disclosed by the present invention.

[0036] Figure 2a This is the infrared spectrum of the gemini benzenesulfonic acid-based ionic liquid surfactant prepared in Example 12.

[0037] Figure 2b This is the nuclear magnetic spectrum of the gemini benzenesulfonic acid-based ionic liquid surfactant prepared in Example 12. Detailed implementation manners

[0038] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the embodiments of the specification.

[0039] In the present application: EDC represents 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

[0040] DCC represents dicyclohexylcarbodiimide.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0042] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0043] The reaction route of the present invention is as follows:

[0044]

[0045] M is an organic cation.

[0046] Further, the organic cation is one of a benzyltrimethylammonium salt cation, a dimethylhydroxyethylammonium salt cation, a trimethylammonium salt cation, an amidine-based quaternary ammonium salt cation, an imidazole-based quaternary ammonium salt cation, NH 4 + , and a pyridine-based quaternary ammonium salt cation.

[0047] Example 1

[0048] A gemini benzenesulfonic acid-based ionic liquid surfactant, whose structural formula is shown in formula (1):

[0049]

[0050] Wherein: R is a straight-chain alkyl group with 12 carbon atoms;

[0051] M is an organic cation.

[0052] Further, the organic cation is a benzyltrimethyl quaternary ammonium salt cation.

[0053] Example 2

[0054] A gemini benzenesulfonic acid-based ionic liquid surfactant, whose structural formula is shown in Formula (1):

[0055]

[0056]

[0057] Wherein: R is a straight-chain alkyl group with 14 carbon atoms;

[0058] M is an organic cation.

[0059] Further, the organic cation is a dimethylhydroxyethyl quaternary ammonium salt cation.

[0060] Example 3

[0061] A gemini benzenesulfonic acid-based ionic liquid surfactant, whose structural formula is shown in Formula (1):

[0062]

[0063] Wherein: R is a straight-chain alkyl group with 16 carbon atoms;

[0064] M is an organic cation.

[0065] Further, the organic cation is a trimethyl quaternary ammonium salt cation.

[0066] Example 4

[0067] A gemini benzenesulfonic acid-based ionic liquid surfactant, whose structural formula is shown in Formula (1):

[0068]

[0069] Wherein: R is a straight-chain alkyl group with 18 carbon atoms;

[0070] M is an organic cation.

[0071] Further, the organic cation is an amidine quaternary ammonium salt cation.

[0072] Example 5

[0073] A gemini benzenesulfonic acid-based ionic liquid surfactant, the structural formula of which is shown in formula (1):

[0074]

[0075] Wherein: R is a straight-chain alkyl group with 20 carbon atoms;

[0076] M is an organic cation.

[0077] Furthermore, the organic cation is an imidazole quaternary ammonium salt cation.

[0078] Example 6

[0079] A gemini benzenesulfonic acid-based ionic liquid surfactant, the structural formula of which is shown in formula (1):

[0080]

[0081] Wherein: R is a straight-chain alkyl group with 22 carbon atoms;

[0082] M is an organic cation.

[0083] Furthermore, the organic cation is NH 4 + .

[0084] Example 7

[0085] A gemini benzenesulfonic acid-based ionic liquid surfactant, the structural formula of which is shown in formula (1):

[0086]

[0087] Wherein: R is a straight-chain alkyl group with 24 carbon atoms;

[0088] M is an organic cation.

[0089] Furthermore, the organic cation is a pyridine quaternary ammonium salt cation.

[0090] Example 8 (Comparative Example)

[0091] The preparation method of sodium lauroyl amidosulfonate, in terms of mole parts, the steps are as follows:

[0092] (1), Mix 1 part of fatty acid, 3 parts of EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide), and an appropriate amount of solvent to obtain a mixed solution, then drop 0.5 part of 4,4'-diaminostilbene-2,2'-disulfonic acid into the mixed solution, and then react at a certain temperature for a period of time to obtain a reaction solution, and then obtain gemini fatty acid amide benzenesulfonic acid after post-treatment of the reaction solution;

[0093] (2) Mix the gemini fatty acid amide benzenesulfonic acid, base, and solvent prepared in step (1), stir at room temperature for a period of time to obtain a reaction solution, and then rotary evaporate the reaction solution to remove the solvent to obtain sodium laurate amide benzenesulfonate.

[0094] Further, the fatty acid in step (1) is lauric acid, and its structural formula is as follows:

[0095] R-COOH, where: R is a straight-chain alkyl group with 12 carbon atoms.

[0096] Further, the solvent in step (1) is ethanol.

[0097] Further, the dosage of the solvent in step (1) is 30 parts.

[0098] Further, the reaction temperature in step (1) is 65 °C and the reaction time is 5 h.

[0099] Further, the post-treatment in step (1) is: first rotary evaporation, then drying.

[0100] Further, the base in step (2) is sodium hydroxide.

[0101] Further, the stirring time in step (2) is 1 h.

[0102] Further, the solvent in step (2) is methanol.

[0103] Further, the molar ratio of gemini fatty acid amide benzenesulfonic acid, base, and solvent in step (2) is 1:2.5:50.

[0104] The gemini benzenesulfonic acid-based ionic liquid surfactant is prepared by the above preparation method.

[0105] The above gemini benzenesulfonic acid-based ionic liquid surfactant is used as a flooding agent in oil recovery.

[0106] Example 9

[0107] The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant is as follows in terms of molar parts:

[0108] (1) Mix 1 part of fatty acid, 2 parts of DCC (dicyclohexylcarbodiimide), and an appropriate amount of solvent evenly to obtain a mixed solution, then add 0.2 part of 4,4'-diaminostilbene-2,2'-disulfonic acid dropwise to the mixed solution, and then react at a certain temperature for a period of time to obtain a reaction solution, and then obtain gemini fatty acid amide benzenesulfonic acid after post-treating the reaction solution;

[0109] (2) Mix the gemini fatty acid amide benzenesulfonic acid, base, and solvent prepared in step (1), stir at room temperature for a period of time to obtain a reaction solution, and then rotary evaporate the reaction solution to remove the solvent to obtain the gemini benzenesulfonic acid-based ionic liquid surfactant, abbreviated as SZBHS-9.

[0110] Further, the fatty acid in step (1) is lauric acid, and its structural formula is as follows:

[0111] R-COOH, where: R is a straight-chain alkyl group with 12 carbon atoms.

[0112] Further, the solvent in step (1) is dimethyl sulfoxide.

[0113] Further, the dosage of the solvent in step (1) is 30 parts.

[0114] Further, the reaction temperature in step (1) is 40 °C and the reaction time is 10 h.

[0115] Further, the post-treatment in step (1) is: first rotary evaporation, then drying.

[0116] Further, the base in step (2) is triethylamine.

[0117] Further, the stirring time in step (2) is 1 h.

[0118] Further, the solvent in step (2) is dimethyl sulfoxide.

[0119] Further, the molar ratio of the gemini fatty acid amide benzenesulfonic acid, base, and solvent in step (2) is 1:2:30.

[0120] The gemini benzenesulfonic acid-based ionic liquid surfactant is prepared by the above preparation method.

[0121] The application of the above gemini benzenesulfonic acid-based ionic liquid surfactant as a flooding agent in oil recovery.

[0122] Example 10

[0123] The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant is as follows in terms of molar parts:

[0124] (1) Mix 1 part of fatty acid, 4 parts of EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide), and an appropriate amount of solvent evenly to obtain a mixed solution, then add 0.8 parts of 4,4'-diaminostilbene-2,2'-disulfonic acid dropwise to the mixed solution, and then react at a certain temperature for a period of time to obtain a reaction solution, and then post-treat the reaction solution to obtain the gemini fatty acid amide benzenesulfonic acid;

[0125] (2), Mix the gemini fatty acid amide benzenesulfonic acid, base, and solvent prepared in step (1), stir at room temperature for a period of time to obtain a reaction solution, and then rotary evaporate the reaction solution to remove the solvent to obtain the gemini benzenesulfonic acid-based ionic liquid surfactant, abbreviated as SZBHS-10.

[0126] Further, the fatty acid in step (1) is palmitic acid, and its structural formula is as follows:

[0127] R-COOH, where: R is a straight-chain alkyl group with 16 carbon atoms.

[0128] Further, the solvent in step (1) is N,N-dimethylformamide.

[0129] Further, the dosage of the solvent in step (1) is 100 parts.

[0130] Further, the reaction temperature in step (1) is 100 °C, and the reaction time is 2 h.

[0131] Further, the post-treatment in step (1) is: first rotary evaporation, then drying.

[0132] Further, the base in step (2) is benzyltrimethylammonium.

[0133] Further, the stirring time in step (2) is 4 h.

[0134] Further, the solvent in step (2) is N,N-dimethylformamide.

[0135] Further, the molar ratio of gemini fatty acid amide benzenesulfonic acid, base, and solvent in step (2) is 1:3:100.

[0136] The gemini benzenesulfonic acid-based ionic liquid surfactant is prepared by the above preparation method.

[0137] The application of the above gemini benzenesulfonic acid-based ionic liquid surfactant as a flooding agent in oil recovery.

[0138] Example 11

[0139] The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant is as follows in terms of molar parts:

[0140] (1), Mix 1 part of fatty acid, 2.5 parts of DCC (dicyclohexylcarbodiimide), and an appropriate amount of solvent evenly to obtain a mixed solution, then drop 0.5 part of 4,4'-diaminostilbene-2,2'-disulfonic acid into the mixed solution, and then react at a certain temperature for a period of time to obtain a reaction solution, and then post-treat the reaction solution to obtain gemini fatty acid amide benzenesulfonic acid;

[0141] (2) Mix the gemini fatty acid amide benzenesulfonic acid, base, and solvent prepared in step (1), stir at room temperature for a period of time to obtain a reaction solution, and then rotary evaporate the reaction solution to remove the solvent to obtain the gemini benzenesulfonic acid-based ionic liquid surfactant, abbreviated as SZBHS-11.

[0142] Further, the fatty acid in step (1) is stearic acid, and its structural formula is as follows:

[0143] R-COOH, where: R is a straight-chain alkyl group with 18 carbon atoms.

[0144] Further, the solvent in step (1) is dichloromethane.

[0145] Further, the dosage of the solvent in step (1) is 40 parts.

[0146] Further, the reaction temperature in step (1) is 60 °C, and the reaction time is 3 h.

[0147] Further, the post-treatment in step (1) is: first rotary evaporation, then drying.

[0148] Further, the base in step (2) is ammonia water.

[0149] Further, the stirring time in step (2) is 3 h.

[0150] Further, the solvent in step (2) is dichloromethane.

[0151] Further, the molar ratio of the gemini fatty acid amide benzenesulfonic acid, base, and solvent in step (2) is 1:2:40.

[0152] The gemini benzenesulfonic acid-based ionic liquid surfactant is prepared by the above preparation method.

[0153] Application of the above gemini benzenesulfonic acid-based ionic liquid surfactant as a flooding agent in oil recovery.

[0154] Example 12

[0155] A preparation method of a gemini benzenesulfonic acid-based ionic liquid surfactant, in terms of molar parts, the steps are as follows:

[0156] (1) Mix 1 part of fatty acid, 4 parts of EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide), and an appropriate amount of solvent evenly to obtain a mixed solution, then add 0.5 part of 4,4'-diaminostilbene-2,2'-disulfonic acid dropwise to the mixed solution, and then react at a certain temperature for a period of time to obtain a reaction solution, and then post-treat the reaction solution to obtain gemini fatty acid amide benzenesulfonic acid;

[0157] (2) Mix the gemini fatty acid amide benzenesulfonic acid prepared in step (1), alkali, and solvent, stir at room temperature for a period of time to obtain a reaction solution, and then rotary evaporate the reaction solution to remove the solvent to obtain the gemini benzenesulfonic acid-based ionic liquid surfactant, abbreviated as SZBHS-12.

[0158] Further, the fatty acid in step (1) is arachidic acid, and its structural formula is as follows:

[0159] R-COOH, where: R is a straight-chain alkyl group with 20 carbon atoms.

[0160] Further, the solvent in step (1) is methanol.

[0161] Further, the dosage of the solvent in step (1) is 50 parts.

[0162] Further, the reaction temperature in step (1) is 60 °C, and the reaction time is 3 h.

[0163] Further, the post-treatment in step (1) is: first rotary evaporation, then drying.

[0164] Further, the alkali in step (2) is benzyltrimethylammonium hydroxide. In another embodiment, it is substantially the same as Example 13, except that the alkali in step (2) is choline hydroxide.

[0165] Further, the stirring time in step (2) is 2 h.

[0166] Further, the solvent in step (2) is methanol.

[0167] Further, the molar ratio of the gemini fatty acid amide benzenesulfonic acid, alkali, and solvent in step (2) is 1:2.5:30.

[0168] The gemini benzenesulfonic acid-based ionic liquid surfactant is prepared by the above preparation method.

[0169] The application of the above gemini benzenesulfonic acid-based ionic liquid surfactant as a flooding agent in oil recovery.

[0170] Example 13

[0171] The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant, in terms of molar parts, the steps are as follows:

[0172] (1) Mix 1 part of fatty acid, 3 parts of EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide), and an appropriate amount of solvent evenly to obtain a mixed solution. Then, add 0.5 part of 4,4'-diaminostilbene-2,2'-disulfonic acid dropwise to the mixed solution, and react at a certain temperature for a period of time to obtain a reaction solution. After post-treatment of the reaction solution, a gemini fatty acid amide benzenesulfonic acid is obtained.

[0173] (2) Mix the gemini fatty acid amide benzenesulfonic acid prepared in step (1), a base, and a solvent, stir at room temperature for a period of time to obtain a reaction solution, and then rotary evaporate the reaction solution to remove the solvent to obtain sodium lauroyl amide benzenesulfonate, abbreviated as SZBHS-13.

[0174] Furthermore, the fatty acid in step (1) is tetracosanoic acid, and its structural formula is as follows:

[0175] R-COOH, where: R is a straight-chain alkyl group with 24 carbon atoms.

[0176] Furthermore, the solvent in step (1) is ethanol.

[0177] Furthermore, the amount of the solvent in step (1) is 30 parts.

[0178] Furthermore, the reaction temperature in step (1) is 65 °C, and the reaction time is 5 h.

[0179] Furthermore, the post-treatment in step (1) is: first rotary evaporation, then drying.

[0180] Furthermore, the base in step (2) is tetramethylammonium hydroxide.

[0181] Furthermore, the stirring time in step (2) is 1 h.

[0182] Furthermore, the solvent in step (2) is methanol.

[0183] Furthermore, the molar ratio of the gemini fatty acid amide benzenesulfonic acid, the base, and the solvent in step (2) is 1:2.5:50.

[0184] The gemini benzenesulfonic acid-based ionic liquid surfactant is prepared by the above preparation method.

[0185] The application of the above gemini benzenesulfonic acid-based ionic liquid surfactant as a flooding agent in oil recovery.

[0186] Performance test:

[0187] Test Example 1. Interfacial tension of the gemini benzenesulfonic acid-based ionic liquid surfactant:

[0188] The interfacial tensions of the surfactant aqueous solutions with the same volume ratio prepared in Examples 9 - 13 were measured at 45°C using a spinning drop interfacial tensiometer, with the sodium lauroyl amide benzenesulfonate prepared in Example 8 as the control sample. The results are shown in Table 1.

[0189] Test Example 2: Salt tolerance performance of gemini benzenesulfonic acid ionic liquid surfactants

[0190] Brine with different salinities (containing only Ca 2+ , Na + , Mg 2+ ions) was prepared, and the surfactant aqueous solutions prepared in Examples 9 - 13 were prepared with brine of different salinities to make the mass fractions the same. The sodium lauroyl amide benzenesulfonate prepared in Example 8 was used as the control sample. The results are shown in Table 1.

[0191] Test Example 3: Self - emulsification of gemini benzenesulfonic acid ionic liquid surfactants

[0192] Equal volumes of the surfactant aqueous solutions (with the same concentration) prepared in Examples 9 - 13 and paraffin oil were taken, and the emulsification situation was observed by inverting them the same number of times up and down. The sodium lauroyl amide benzenesulfonate prepared in Example 8 was used as the control sample. The results are shown in Table 1.

[0193] Test Example 4: The gemini benzenesulfonic acid ionic liquid surfactant prepared in Example 12 (trimethylammonium arachidoyl amide benzenesulfonate, abbreviated as SZBHS - 12) was subjected to infrared spectroscopy and nuclear magnetic resonance spectroscopy. Its infrared spectrum and nuclear magnetic resonance spectrum are shown in Figure 2a , 2b respectively. It can be seen from Figure 2a that the characteristic absorption peak of the sulfonate group is at 2800 cm -1 , the absorption peak at 1200 cm -1 belongs to the methylene absorption peak, and the absorption peak at 1480 cm -1 belongs to the vibration absorption peaks of the amide group and quaternary ammonium salt. From the Figure 2b nuclear magnetic resonance spectrum, the peak at 0.79 - 0.82 ppm belongs to the hydrogen on CH 3 , the peak at 3.21 ppm belongs to the hydrogen on N(CH 3 ) 3 , the peak at 1.46 - 1.53 ppm belongs to the hydrogen of the methylene in CH 2 CH 2 COOH, the peak at 3.90 ppm belongs to the hydrogen of the methylene on the benzene ring of C 6 H 5 CH 2 , and the peak at 7.34 - 7.50 ppm belongs to the hydrogen of C 6 H 5 CH 2Hydrogen on the benzene ring. It is confirmed that the gemini arachidic acid amide benzenesulfonic acid trimethyl quaternary ammonium salt is successfully prepared.

[0194] Table 1 Performance comparison table of different gemini benzenesulfonic acid-based ionic liquid surfactants

[0195]

[0196] As can be seen from Table 1, the surfactants prepared in Examples 9-13 all have good solubility, which is beneficial for on-site preparation. It shows that the introduction of the benzene ring structure does not lead to an increase in the hydrophobicity of the surfactants described in the present invention. Instead, the introduction of the amide bond enhances the hydrophilicity.

[0197] The surfactants prepared in Examples 9-13 all exhibit relatively low interfacial tensions, and the C16 and C18 hydrophobic tail chains exhibit even lower interfacial tensions.

[0198] The surfactants prepared in Examples 9-13 show good salt tolerance performance, indicating that they can be applied to high-salinity oil reservoirs.

[0199] The surfactants prepared in Examples 9-13 show good self-emulsifying ability, and the palmitic acid and stearic acid systems can even be completely self-emulsified. Therefore, they can effectively improve the oil recovery of tertiary oil recovery.

[0200] In addition, a performance comparison table of other gemini benzenesulfonic acid-based ionic liquid surfactants is attached, as shown in Table 2 specifically. Table 2 Performance comparison table of other gemini benzenesulfonic acid-based ionic liquid surfactants

[0201]

[0202] It should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A gemini benzenesulfonic acid-based ionic liquid surfactant, characterized in that its structural formula is as shown in formula (1): Wherein: R is a straight-chain alkyl group with 12-24 carbon atoms; M is an organic cation, and the organic cation is one of benzyltrimethyl quaternary ammonium salt cation, dimethyl hydroxyethyl quaternary ammonium salt cation, trimethyl quaternary ammonium salt cation, amidine quaternary ammonium salt cation, imidazole quaternary ammonium salt cation, NH 4 + , and pyridine quaternary ammonium salt cation.

2. A preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 1, characterized in that in terms of molar parts, the steps are as follows: (1), Mix 1 part of fatty acid, 2-4 parts of EDC or DCC, and an appropriate amount of solvent evenly to obtain a mixed solution, then drop 0.2-0.8 part of 4,4'-diaminostilbene-2,2'-disulfonic acid into the mixed solution, and then react at a certain temperature for a period of time to obtain a reaction solution, and then obtain gemini fatty acid amide benzenesulfonic acid after post-treatment of the reaction solution; (2), Mix the gemini fatty acid amide benzenesulfonic acid prepared in step (1), alkali, and solvent, stir at room temperature for a period of time to obtain a reaction solution, and then rotary evaporate the reaction solution to remove the solvent to obtain the gemini benzenesulfonic acid-based ionic liquid surfactant.

3. The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 2, characterized in that the general formula of the fatty acid in step (1) is as follows: R-COOH, wherein: R is a straight-chain alkyl group with 12-24 carbon atoms.

4. The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 2, characterized in that the solvent in step (1) is one of dimethyl sulfoxide, N,N-dimethylformamide, dichloromethane, ethanol, and methanol; the dosage of the solvent in step (1) is at least 30 parts, preferably 30-100 parts.

5. The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 2, characterized in that the reaction temperature in step (1) is 40-100 °C, and the reaction time is at least 2 h, preferably 2-10 h.

6. The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 2, characterized in that the post-treatment in step (1) is: first rotary evaporation, then drying.

7. The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 2, characterized in that the alkali in step (2) is one of triethylamine, benzyltrimethylamine, ammonia water, benzyltrimethylammonium hydroxide, choline hydroxide, and tetramethylammonium hydroxide.

8. The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 2, characterized in that the stirring time in step (2) is at least 1 h, preferably 1-8 h.

9. The preparation method of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 2, characterized in that the solvent in step (2) is one of dimethyl sulfoxide, N,N-dimethylformamide, dichloromethane, ethanol, and methanol; the molar ratio of gemini fatty acid amide benzenesulfonic acid, alkali, and solvent in step (2) is 1:(2-3):(30-100).

10. A gemini benzenesulfonic acid-based ionic liquid surfactant, characterized in that it is prepared by the preparation method described in any one of claims 2-9.

11. Application of the gemini benzenesulfonic acid-based ionic liquid surfactant according to claim 1 or 10 as an oil displacement agent in oil exploitation.

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