A fluorocarbon cationic surfactant and its preparation method and drainage aid

Abstract

The present application relates to the field of surfactant preparation technology, and specifically to a fluorocarbon cationic surfactant, its preparation method, and drainage aid. The preparation method of the fluorocarbon cationic surfactant of the present application comprises: reacting perfluorohexyl ethylsulfonyl chloride and N,N-dimethylethanolamine under a first reaction condition to generate compound I; reacting compound I and a quaternizing agent X-R under a second reaction condition, and removing impurities from the reaction product after the reaction is completed to obtain a fluorocarbon cationic surfactant; wherein X is ‑Cl or ‑Br, and R is ‑C7H7, ‑CH2CH2OH, ‑CH(CH3)2, or ‑CH2CH2CH3. The fluorocarbon cationic surfactant of the present application avoids the use of PFOS-containing ingredients and retains the high surface activity of PFOS to the greatest extent, making it an ideal cationic surfactant for drainage aids 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, a preparation method thereof, and a drainage aid. Background Art

[0002] Hydraulic fracturing is an important reservoir reconstruction method in tertiary oil recovery. Hydraulic fracturing first creates cracks in tight reservoirs by applying high pressure to the formation. Then, a fracturing fluid, prepared by mixing a sand-carrying fluid, sand particles, drainage agents, and other additives, is injected into the formation cracks. Once the fracturing fluid reaches the formation cracks, it breaks down due to the formation temperature. The sand particles support the formation cracks and increase the flow conductivity. The broken fracturing fluid is then returned to the surface under the formation pressure. The drainage agents added to the fracturing fluid can reduce water lock damage and increase the flow conductivity of the reservoir cracks during the fracturing fluid return. Therefore, drainage agents are important additives in fracturing fluids. They are required to have low surface tension, interfacial tension, and dilution resistance at low concentrations, so that the fracturing fluid can be smoothly returned in complex formation environments.

[0003] Generally, drainage aids used in oil fields are compound mixtures composed of fluorocarbon surfactants and hydrocarbon surfactants. The fluorine-containing structure itself has low cohesive energy and low polarity, and is a highly surface-active material. The hydrophobic chain segment of hydrocarbon surfactants has a high polarity, and when molecules approach each other, they produce a significant repulsive force due to the intermolecular interaction force (van der Waals force). Therefore, when the concentration of hydrocarbon surfactants exceeds the CMC, the degree of molecular arrangement at the interface is significantly affected by the van der Waals force. The fluorocarbon hydrophobic chains in fluorocarbon surfactants have the characteristics of low polarity and extremely low intermolecular interaction force. Therefore, when the concentration of fluorocarbon surfactants exceeds the CMC, they are arranged more tightly 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 urgently needs alternative products. Summary of the Invention

[0005] The purpose of the present application is to provide a fluorocarbon cationic surfactant that is chemically stable, environmentally friendly and surface active, as well as a preparation method and a drainage aid. The embodiments of the present application are achieved in this way.

[0006] In order to achieve the above objectives, 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, and X is Cl or Br.

[0009] A 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-dimethylethanolamine react under the first reaction conditions to generate compound I;

[0011]

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

[0013]

[0014] Wherein 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 perfluorohexylethylsulfonyl chloride to N,N-dimethylethanolamine is 1:1.1-1.3.

[0016] In some embodiments, the second reaction conditions include 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 conditions further includes: 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.

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

[0018] The third aspect of the present application provides a drainage aid, comprising: 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] The beneficial effects of the present application are as follows: the novel fluorocarbon cationic surfactant prepared by the present invention uses perfluorohexylethylsulfonyl chloride as a hydrophobic structure, introduces a tertiary amine segment by an esterification reaction with N,N-dimethylethanolamine, and synthesizes a fluorinated tertiary amine intermediate (i.e., compound I), which is then subjected to a quaternization reaction between the fluorinated tertiary amine intermediate and a quaternizing agent to prepare a fluorocarbon cationic surfactant.

[0021] This application utilizes perfluorohexyl ethyl sulfonyl chloride as a fluorocarbon hydrophobic segment, which not only avoids the use of prohibited raw materials such as perfluorooctyl groups, but also, because the perfluorohexyl ethyl structure has only four fewer fluorine atoms in the molecule than the perfluorooctyl structure, while retaining its linear structure and thirteen fluorine atoms, the low polarity and low van der Waals force of the hydrophobic segment are largely retained, making the prepared fluorocarbon surfactant have excellent surface activity, making it an ideal substitute for PFOS-type surfactants.

[0022] The fluorocarbon hydrophobic chain segments in the fluorocarbon cationic surfactants of the present application have low polarity and weak intermolecular hydrogen bonds and van der Waals forces, which can make the surfactant molecules more closely arranged at the gas-liquid interface. In addition, due to the low molecular weight of the fluorocarbon cationic surfactants of the present application, they exhibit good surface activity and resistance to water dilution.

[0023] In summary, the novel fluorocarbon cationic surfactant of the present application exhibits both the extremely high surface activity of fluorocarbon cationic surfactants and the good oil-water interfacial activity of hydrocarbon cationic surfactants, and a good synergistic effect is produced between the two structures, so that the compounded fluorosurfactant 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, making it an ideal cationic surfactant for drainage aids in tertiary oil recovery. DETAILED DESCRIPTION

[0024] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions 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, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0027] For the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described herein. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any manner, and all possible combinations should be considered to be within the scope of this specification.

[0028] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, 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 equally within the scope limited by the appended claims of the application.

[0029] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and ratios are expressed by weight.

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

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

[0032]

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

[0034] A 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-dimethylethanolamine 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 impurity-removed to obtain a fluorocarbon cationic surfactant:

[0038]

[0039] Wherein 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 perfluorohexylethylsulfonyl chloride to N,N-dimethylethanolamine is 1:1.1-1.3.

[0041] In some embodiments, the second reaction conditions include 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 conditions further includes: 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.

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

[0043] The third aspect of the present application provides a drainage aid, comprising: 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 the reactants perfluorohexyl ethylsulfonyl chloride (44.7 g, 0.1 mol) and N,N-dimethylformamide (solvent, 100 g) to a small glass reactor, heat to 70°C, and slowly add N,N-dimethylethanolamine (9.8 g, 0.11 mol) dropwise. After the addition is complete, continue to keep warm for 3 hours.

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

[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 the reactants perfluorohexyl ethylsulfonyl chloride (44.7 g, 0.1 mol) and N,N-dimethylformamide (100 g) to a small glass reactor, heat to 80°C, and slowly add N,N-dimethylethanolamine (9.8 g, 0.11 mol) dropwise. After the addition is complete, continue to keep warm for 2 hours;

[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. If the residual amine value was less than or equal to 0.05, the reaction 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 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 the reactants perfluorohexylethylsulfonyl chloride (44.7 g, 0.1 mol) and butanone (solvent, 100 g) to a small glass reactor, raise the temperature to 60°C, and slowly add N,N-dimethylethanolamine (10.7 g, 0.12 mol) dropwise. After the addition is complete, continue to keep warm for 2 hours;

[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 warm for 4 h. During the warming period, sodium hydroxide was added to maintain the pH value in the reactor between 9 and 10. Samples were taken for residual amine value testing. If the residual amine value was less than or equal to 0.05, the reaction was qualified and the reaction was terminated. Otherwise, benzyl chloride was continued to be 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 the reactants perfluorohexylethylsulfonyl chloride (44.7 g, 0.1 mol) and anhydrous ethanol (100 g) to a small glass reactor, heat to 80°C, and slowly add N,N-dimethylethanolamine (10.7 g, 0.12 mol) dropwise. After the addition is complete, continue to keep warm for 2 hours;

[0059] Then the temperature was lowered to 40° C. and 11.7 g, 0.15 mol, of chloropropane was added dropwise. After the addition was completed, the temperature was raised to 65° C. and kept warm for 5 h. During the warming period, sodium hydroxide was added to keep the pH value in the reactor between 9 and 10. Samples were taken for residual amine value testing. When the residual amine value was less than or equal to 0.05, the reaction 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 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 dissolved by ethanol and dried to obtain a fluorocarbon cationic surfactant.

[0061] Surfactant performance test

[0062] A 0.3% aqueous solution of a fluorocarbon cationic surfactant was prepared using the fluorocarbon cationic surfactant provided in the above examples. Samples were prepared using the half-and-half dilution method. Surface tension was measured using a KRUSS K100 interfacial tension meter, and the critical micellar solubility was calculated. Comparisons were made with perfluorooctanesulfonyl ethyldimethylbenzyl ammonium chloride and dodecyltrimethylammonium chloride, as shown in Table 1.

[0063] Table 1 Performance test results

[0064]

[0065] As can be seen in Table 1, fluorocarbon surfactants have lower CMCs and surface tensions than hydrocarbon surfactants. This is due to the low polarity of the fluorinated segments of fluorocarbon surfactants and the reduced intermolecular van der Waals forces. Furthermore, compared to fluorocarbon cationic surfactants with a PFOS structure, the critical micelle solubility and surface tension of the examples of the present invention were increased, but the increase was limited, confirming that the fluorocarbon cationic surfactants of the present invention are superior alternatives to perfluorooctyl surfactants.

[0066] Compound performance test

[0067] The fluorocarbon cationic surfactant provided in each example 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. The surface tension of each drainage agent at concentrations of 30 ppm and 100 ppm was tested and compared with a blank sample containing no 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 agent 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. This proves that when the drainage agent is used at a concentration of 100ppm, it still has low surface tension and interfacial tension after being diluted three times with water. It has very good surface surfactant dilution resistance under low concentration conditions and is a very good cationic drainage agent. The blank sample without fluorocarbon cations has a significantly higher surface and interfacial tension at low concentrations than the fluorocarbon drainage agent. This is because the surface and interfacial tension of a single surfactant component is affected by its cmc. After compounding, the different components of the surfactant produce a synergistic effect, and the surface and interfacial activity are enhanced.

[0071] Although the present invention has been disclosed above in terms of preferred embodiments, 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, and X is Cl or Br.

2. The method for preparing a fluorocarbon cationic surfactant according to claim 1, wherein: The preparation method comprises: Perfluorohexylethylsulfonyl chloride and N,N-dimethylethanolamine 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 impurity-removed to obtain a fluorocarbon cationic surfactant: Wherein R is -C7H7, -CH2CH2OH, -CH(CH3)2 or -CH2CH2CH3.

3. The method for preparing a fluorocarbon cationic surfactant according to claim 2, wherein: 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-dimethylethanolamine of 1:1.1-1.

3.

4. The method for preparing a fluorocarbon cationic surfactant according to claim 2, wherein: The second reaction conditions include 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 further comprises: maintaining the pH value of the reaction system at 9-10 during the reaction, and dropwise adding the quaternary ammonium reagent 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, wherein: After the reaction is completed, the reaction product is cleaned of impurities, including: First, the reaction product is distilled under reduced pressure, then washed with water three times, and finally washed with ethanol at least three times.

6. A drainage agent, characterized in that include: The fluorocarbon cationic surfactant according to 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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