Fluorocarbon cationic surfactant, preparation method thereof and cleanup additive

Abstract

The invention relates to the technical field of surfactant preparation, in particular to a fluorocarbon cationic surfactant, a preparation method thereof and a cleanup additive. The preparation method of the fluorocarbon cationic surfactant comprises the following steps: perfluorohexyl ethyl sulfonyl chloride and N, N-dimethylacetamide are subjected to a reaction under a first reaction condition, and a compound I is generated; reacting the compound I with a quaternization reagent X-R under a second reaction condition, and removing impurities from a reaction product after the reaction is completed to obtain the fluorocarbon cationic surfactant, wherein X is-Cl or-Br, and R is-C7H7,-CH2CH2OH,-CH (CH3) 2 or-CH2CH2CH3. The structural formula of the compound is shown in the description. According to the fluorocarbon cationic surfactant disclosed by the invention, the use of PFOS-containing components is avoided, the characteristic of high surface activity of PFOS is reserved to the greatest extent, and the fluorocarbon cationic surfactant is an ideal cationic surfactant for a cleanup additive in tertiary oil recovery.

Description

Technical Field

[0001] The present application relates to the technical field of surfactant preparation, and in particular to a fluorocarbon cationic surfactant and a preparation method and a drainage aid thereof. Background Art

[0002] Hydraulic fracturing is an important reservoir transformation method in tertiary oil recovery. Hydraulic fracturing first creates cracks in dense reservoirs by applying high pressure to the formation, and then injects the fracturing fluid prepared by mixing sand-carrying fluid, sand particles, drainage agents and other additives into the formation cracks. After the fracturing fluid reaches the formation cracks, it breaks the gel under the heating of the formation temperature, and the sand particles support the formation cracks to increase the conductivity. The fracturing fluid after breaking the gel is returned to the ground under the formation pressure. The drainage agent added to the fracturing fluid can reduce water lock damage and increase the reservoir crack conductivity while the fracturing fluid is returned. Therefore, the drainage agent is an important additive in the fracturing fluid, which is required to have low surface tension, interfacial tension and dilution resistance at low concentrations, so that the fracturing gel-breaking fluid can be smoothly returned in a complex formation environment.

[0003] Generally, drainage aids used in oil fields are a compound mixture composed of fluorocarbon surfactants and hydrocarbon surfactants. The fluorine-containing structure itself has low cohesive energy and low polarity, and is a high-surface active material. The hydrophobic chain segment of hydrocarbon surfactants has a high polarity, and when molecules approach each other, they produce obvious repulsion due to the intermolecular interaction force (van der Waals force). Therefore, when the concentration of hydrocarbon surfactants exceeds CMC, the degree of molecular arrangement at the interface is significantly affected by van der Waals force. The fluorocarbon hydrophobic chain in fluorocarbon surfactants has the characteristics of low polarity and extremely low intermolecular interaction force. Therefore, when the concentration of fluorocarbon surfactants exceeds CMC, they are arranged more closely at the gas-liquid interface, and the surface tension of their aqueous solutions is extremely low. Perfluorooctyl surfactants are particularly effective.

[0004] However, studies have shown that perfluorooctane surfactants are highly persistent, difficult to decompose, highly toxic, and extremely harmful to the environment. Since December 2019, my country has completely banned the use of perfluorooctane sulfonate (PFOS) and its derivatives, and the market is in urgent need of alternative products. Summary of the invention

[0005] The purpose of the present application is to provide a fluorocarbon cationic surfactant having chemical stability, environmental friendliness and surface activity, a preparation method thereof and a drainage aid, and the embodiments of the present application are implemented as follows.

[0006] In order to achieve the above-mentioned object, the first aspect of the present application provides a fluorocarbon cationic surfactant having the following structural formula:

[0007]

[0008] Wherein, R is -C7H7, -CH2CH2OH, -CH(CH3)2 or -CH2CH2CH3.

[0009] The second aspect of the present application provides a method for preparing a fluorocarbon cationic surfactant, the preparation method comprising:

[0010] Perfluorohexylethylsulfonyl chloride and N,N-dimethylacetamide react under the first reaction conditions to generate compound I;

[0011]

[0012] The compound I and the quaternary ammonium reagent XR react under the second reaction conditions, and after the reaction is completed, the reaction product is impurity-removed to obtain a fluorocarbon cationic surfactant;

[0013]

[0014] Wherein X is -Cl or -Br, and R is -C7H7, -CH2CH2OH, -CH(CH3)2 or -CH2CH2CH3.

[0015] In some embodiments, the first reaction conditions include a reaction temperature of 60° C.-80° C. and a reaction time of 2 h-3 h, and the molar ratio of perfluorohexyl ethylsulfonyl chloride to N,N-dimethylacetamide is 1:1.1-1.3.

[0016] In some embodiments, the second reaction condition includes a reaction temperature of 40°C-80°C and a reaction time of 3h-5h; the reaction of compound I and quaternary ammonium reagent XR under the second reaction condition also includes: during the reaction, the pH value of the reaction system is maintained at 9-10, and the quaternary ammonium reagent is added dropwise to the reaction system until the residual amine value of the reaction system is less than or equal to 0.05.

[0017] In some embodiments, after the reaction is completed, the reaction product is subjected to impurity removal, including: firstly performing reduced pressure distillation on the reaction product, then washing the reaction product with water three times, and finally washing the reaction product with ethanol at least three times.

[0018] The third aspect of the present application provides a drainage aid, including: a fluorocarbon cationic surfactant, water, ethylene glycol monobutyl ether and dodecyltrimethylammonium chloride.

[0019] In some embodiments, the mass ratio of the fluorocarbon cationic surfactant, water, ethylene glycol monobutyl ether and dodecyltrimethylammonium chloride is: 10:20-25:50-60:20-30.

[0020] Beneficial effects of the present application: The novel fluorocarbon cationic surfactant prepared by the present invention uses perfluorohexyl ethylsulfonyl chloride as a hydrophobic structure, introduces a tertiary amine segment by an esterification reaction with N,N-dimethylethanolamine, synthesizes a fluorinated tertiary amine intermediate (i.e., compound I), and then the fluorinated tertiary amine intermediate is reacted with a quaternizing agent to prepare a fluorocarbon cationic surfactant.

[0021] The present application utilizes perfluorohexyl ethyl sulfonyl chloride as a fluorocarbon hydrophobic segment, which not only avoids the use of prohibited raw materials such as perfluorooctyl, but also because the perfluorohexyl ethyl structure has only four fewer fluorine atoms in the molecule than the perfluorooctyl structure, but retains its linear structure and thirteen fluorine atoms, and the low polarity and low van der Waals force of the hydrophobic segment are largely retained, so that the prepared fluorocarbon surfactant has very good surface activity and can become an ideal substitute for PFOS surfactants;

[0022] The fluorocarbon hydrophobic chain segments in the fluorocarbon cationic surfactant of the present application have the characteristics of low polarity, weak intermolecular hydrogen bonds and weak van der Waals forces, which can make the surfactant molecules more closely arranged at the gas-liquid interface, and because the fluorocarbon cationic surfactant of the present application has a low molecular weight, it exhibits good surface activity and water dilution resistance;

[0023] In summary, the novel fluorocarbon cationic surfactant of the present application not only exhibits the extremely high surface activity of fluorocarbon cationic surfactants, but also exhibits the good oil-water interfacial activity of hydrocarbon cationic surfactants, and the two structures also produce a good synergistic effect, so that the compounded fluorinated surfactant mixture has low surface tension, oil-water interfacial tension and excellent water dilution resistance. At the same time, the fluorocarbon cationic surfactant of the present application avoids the use of PFOS-containing ingredients and retains the high surface activity characteristics of PFOS to the greatest extent, and is an ideal cationic surfactant for drainage aids in tertiary oil recovery. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0025] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0026] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0027] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0028] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0029] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight.

[0030] The fluorocarbon cationic surfactant and its preparation method and drainage aid provided in the present application are further described below in conjunction with specific examples.

[0031] The present application provides a fluorocarbon cationic surfactant, which has the following structural formula:

[0032]

[0033] Wherein, R is -C7H7, -CH2CH2OH, -CH(CH3)2 or -CH2CH2CH3.

[0034] The second aspect of the present application provides a method for preparing a fluorocarbon cationic surfactant, the preparation method comprising:

[0035] Perfluorohexylethylsulfonyl chloride and N,N-dimethylacetamide react under the first reaction conditions to generate compound I:

[0036]

[0037] The compound I and the quaternary ammonium reagent XR are reacted under the second reaction conditions, and after the reaction is completed, the reaction product is decontaminated to obtain a fluorocarbon cationic surfactant:

[0038]

[0039] Wherein X is -Cl or -Br, and R is -C7H7, -CH2CH2OH, -CH(CH3)2 or -CH2CH2CH3.

[0040] In some embodiments, the first reaction conditions include a reaction temperature of 60° C.-80° C. and a reaction time of 2 h-3 h, and the molar ratio of perfluorohexyl ethylsulfonyl chloride to N,N-dimethylacetamide is 1:1.1-1.3.

[0041] In some embodiments, the second reaction condition includes a reaction temperature of 40°C-80°C and a reaction time of 3h-5h; the reaction of compound I and quaternary ammonium reagent XR under the second reaction condition also includes: during the reaction, the pH value of the reaction system is maintained at 9-10, and the quaternary ammonium reagent is added dropwise to the reaction system until the residual amine value of the reaction system is less than or equal to 0.05.

[0042] In some embodiments, after the reaction is completed, the reaction product is subjected to impurity removal, including: firstly performing reduced pressure distillation on the reaction product, then washing the reaction product with water three times, and finally washing the reaction product with ethanol at least three times.

[0043] The third aspect of the present application provides a drainage aid, including: a fluorocarbon cationic surfactant, water, ethylene glycol monobutyl ether and dodecyltrimethylammonium chloride.

[0044] In some embodiments, the mass ratio of the fluorocarbon cationic surfactant, water, ethylene glycol monobutyl ether and dodecyltrimethylammonium chloride is: 10:20-25:50-60:20-30.

[0045] Example 1

[0046] Add reactants perfluorohexyl ethylsulfonyl chloride (44.7 g, 0.1 mol) and N,N-dimethylformamide (solvent, 100 g) into a small glass reactor, heat to 70°C, slowly drop N,N-dimethylethanolamine (9.8 g, 0.11 mol), and keep warm for 3 h after the addition is complete;

[0047] Then, benzyl chloride is added dropwise. After the addition is completed, the temperature is raised to 80°C and kept warm for 5 hours. During the warming, sodium hydroxide is added to keep the pH value in the reactor between 9 and 10. Samples are taken to test the residual amine value. When the residual amine value is less than or equal to 0.05, it is qualified and the reaction is terminated. Otherwise, benzyl chloride is added dropwise (a total of 15.2 g, i.e., 0.12 mol, of benzyl chloride is added in this embodiment).

[0048] The solvent is removed by distillation under reduced pressure, the unreacted product and sodium hydroxide are removed by washing with water, and then the inorganic salt is removed by dissolving with ethanol. After drying, the fluorocarbon cationic surfactant is obtained.

[0049] Example 2

[0050] Add reactants perfluorohexylethylsulfonyl chloride (44.7 g, 0.1 mol) and N,N-dimethylformamide (100 g) into a small glass reactor, heat to 80°C, slowly drop N,N-dimethylethanolamine (9.8 g, 0.11 mol), and keep warm for 2 h after the addition is complete;

[0051] Then the temperature was lowered to 40°C and chloropropane was added dropwise. After the addition was completed, the temperature was raised to 70°C and kept warm for 5 hours. During the warming period, sodium hydroxide was added dropwise to keep the pH value in the reactor between 9 and 10. The residual amine value was tested by sampling. When the residual amine value was less than or equal to 0.05, it was qualified and the reaction was terminated. Otherwise, benzyl chloride was continued to be added dropwise (a total of 10.2 g, i.e., 0.13 mol, of chloropropane was added dropwise in this embodiment);

[0052] The solvent is removed by distillation under reduced pressure, the unreacted product and sodium hydroxide are removed by washing with water, and then the inorganic salt is removed by dissolving with ethanol. After drying, the fluorocarbon cationic surfactant is obtained.

[0053] Example 3

[0054] Add reactants perfluorohexyl ethylsulfonyl chloride (44.7 g, 0.1 mol) and butanone (solvent, 100 g) into a small glass reactor, heat to 60°C, slowly drop N,N-dimethylethanolamine (10.7 g, 0.12 mol), and keep warm for 2 h after the addition is complete;

[0055] Then the temperature was lowered to 40°C and benzyl chloride (18.9 g, 0.15 mol) was continuously added dropwise. After the addition was completed, the temperature was raised to 80°C and kept for 4 hours. During the insulation, sodium hydroxide was added to keep the pH value in the reactor between 9 and 10. The residual amine value was tested by sampling. When the residual amine value was less than or equal to 0.05, it was qualified and the reaction was terminated. Otherwise, benzyl chloride was continuously added dropwise (a total of 15.2 g, i.e., 0.15 mol, of benzyl chloride was added dropwise in this embodiment);

[0056] The solvent is removed by distillation under reduced pressure, the unreacted product and sodium hydroxide are removed by washing with water, and then the inorganic salt is removed by dissolving with ethanol. After drying, the fluorocarbon cationic surfactant is obtained.

[0057] Example 4

[0058] Add reactants perfluorohexyl ethylsulfonyl chloride (44.7 g, 0.1 mol) and anhydrous ethanol (100 g) into a small glass reactor, heat to 80°C, slowly drop N,N-dimethylethanolamine (10.7 g, 0.12 mol), and keep warm for 2 h after the addition is complete;

[0059] Then the temperature was lowered to 40°C and 11.7 g of chloropropane (0.15 mol) was added dropwise. After the addition was completed, the temperature was raised to 65°C and kept for 5 h. During the insulation, sodium hydroxide was added to keep the pH value in the reactor between 9 and 10. The residual amine value was tested by sampling. When the residual amine value was less than or equal to 0.05, it was qualified and the reaction was terminated. Otherwise, benzyl chloride was continued to be added dropwise (a total of 11.7 g, i.e., 0.15 mol of chloropropane was added dropwise in this embodiment);

[0060] The solvent is removed by distillation under reduced pressure, the unreacted product and excess sodium hydroxide are removed by washing with water, and then the inorganic salt is removed by dissolving with ethanol. After drying, the fluorocarbon cationic surfactant is obtained.

[0061] Surfactant performance test

[0062] The fluorocarbon cationic surfactant provided in the above example was used to prepare a 0.3% fluorocarbon cationic surfactant aqueous solution, and the sample was prepared by half dilution method. The surface tension was tested by KRUSS K100 surface tension meter, and the critical micelle solubility was calculated. The results were compared with perfluorooctane sulfonyl ester ethyl dimethyl benzyl ammonium chloride and dodecyl trimethyl ammonium chloride, as shown in Table 1.

[0063] Table 1 Performance test results

[0064]

[0065] As can be seen from Table 1, fluorocarbon surfactants have lower cmc and surface tension than hydrocarbon surfactants. This is related to the low polarity of the fluorinated segments of fluorocarbon surfactants and the low van der Waals force between molecules. In addition, compared with the fluorocarbon cationic surfactants with PFOS structure, the critical micelle solubility and surface tension of the embodiments of the present invention are increased, but the increase is limited, which proves that the fluorocarbon cationic surfactant of the present invention is a better substitute for perfluorooctyl structure surfactants.

[0066] Compound performance test

[0067] The fluorocarbon cationic surfactant provided in each embodiment was compounded with dodecyltrimethylammonium chloride, ethylene glycol monobutyl ether and water in a mass ratio of 10:20:50:20 to prepare a drainage agent, and the surface interfacial tension of each drainage agent at a concentration of 30ppm and 100ppm was tested, and compared with a blank sample without a fluorocarbon cationic surfactant. The specific results are shown in Table 2.

[0068] Table 2 Performance test results

[0069]

[0070] As can be seen from Table 2, the surface tension of the drainage aid obtained by compounding the fluorocarbon cationic surfactant of the present application is below 22mN / m at 100ppm and 30ppm, and the interfacial tension is 1mN / m, which proves that when the drainage aid is used at a concentration of 100ppm, it still has a low surface tension and interfacial tension after being diluted three times with water, and has very good surface surfactant dilution resistance under low concentration conditions, and is a very good cationic drainage aid. The surface and interfacial tension of the blank sample without fluorocarbon cations at low concentrations is significantly higher than that of the fluorocarbon drainage aid, because the surface and interfacial tension of a single surfactant component is affected by its cmc, and the different components of the compounded surfactant produce synergistic effects, and the surface and interfacial activity are enhanced.

[0071] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A fluorocarbon cationic surfactant, characterized in that: It has the following structural formula: Wherein, R is -C7H7, -CH2CH2OH, -CH(CH3)2 or -CH2CH2CH3.

2. The method for preparing the fluorocarbon cationic surfactant according to claim 1, characterized in that: The preparation method comprises: Perfluorohexylethylsulfonyl chloride and N,N-dimethylacetamide react under the first reaction conditions to generate compound I: The compound I and the quaternary ammonium reagent XR are reacted under the second reaction conditions, and after the reaction is completed, the reaction product is decontaminated to obtain a fluorocarbon cationic surfactant: Wherein X is -Cl or -Br, and R is -C7H7, -CH2CH2OH, -CH(CH3)2 or -CH2CH2CH3.

3. The method for preparing a fluorocarbon cationic surfactant according to claim 2, characterized in that: The first reaction conditions include a reaction temperature of 60° C.-80° C. and a reaction time of 2 h-3 h, and a molar ratio of perfluorohexyl ethylsulfonyl chloride to N,N-dimethylacetamide of 1:1.1-1.

3.

4. The method for preparing a fluorocarbon cationic surfactant according to claim 2, characterized in that: The second reaction conditions include a reaction temperature of 40°C-80°C and a reaction time of 3h-5h; The reaction of the compound I and the quaternary ammonium reagent XR under the second reaction condition further comprises: maintaining the pH value of the reaction system at 9-10 during the reaction, and adding the quaternary ammonium reagent dropwise to the reaction system until the residual amine value of the reaction system is less than or equal to 0.

05.

5. The method for preparing a fluorocarbon cationic surfactant according to claim 2, characterized in that: After the reaction is completed, the reaction product is cleaned of impurities, including: Firstly, the reaction product is distilled under reduced pressure, then the reaction product is washed with water three times, and finally the reaction product is washed with ethanol at least three times.

6. A drainage aid, characterized in that: include: The fluorocarbon cationic surfactant as claimed in claim 1, water, ethylene glycol monobutyl ether and dodecyltrimethylammonium chloride.

7. The drainage aid according to claim 6, characterized in that: The mass ratio of the fluorocarbon cationic surfactant, water, ethylene glycol monobutyl ether and dodecyltrimethylammonium chloride is 10:20-25:50-60:20-30.

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