Betaine surfactant as well as preparation method and application thereof
By introducing specific repeat units and hydrophilic groups on the backbone of the betaine-type surfactant molecule, the problem of insufficient interfacial activity and viscosity-enhancing ability of betaine-type surfactant is solved, and the recovery rate of the reservoir is improved.
Patent Information
- Application Number
- CN202410025823.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-08
- Publication Date
- 2025-07-08
AI Technical Summary
The existing betaine-type surfactants are difficult to have high interfacial activity and good viscosity-enhancing ability, resulting in low recovery rate of reservoirs.
A specific number of repeat units -CH2-CH2-O- is introduced on the backbone of the conventional alkyl betaine surfactant molecule, and carboxyl-COO- and sulfo-SO3- are introduced at the hydrophilic tail to improve molecular chain length and hydrophilicity.
The combination of high interfacial activity and tackification enhancement ability is achieved, and the recovery rate of the reservoir can be improved without compounding.
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Figure CN120271482A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of surfactants, and in particular, to a betaine surfactant, a preparation method thereof, and an application thereof. Background Art
[0002] Surfactant flooding is a technique for effectively improving oil recovery. According to the types of surfactants used for improving oil recovery, surfactant flooding can be further divided into active water flooding, microemulsion flooding, etc. In recent years, in view of the problem of poor sweep efficiency of conventional surfactants, a series of functional surfactant products with profile control and flooding effects have been developed through fine molecular structure design. Its basic principle is to use the surfactant to emulsify and disperse the crude oil adhered to the wall surface of the high-permeability water flow channel, and block the high-permeability water flow channel through the Jamin effect of large-sized emulsion droplets and the relatively high emulsion viscosity to achieve the purpose of "profile control". At the same time, the high interfacial activity characteristic is used to improve the oil washing efficiency to achieve the purpose of "flooding".
[0003] At present, although the existing surfactant products for improving oil recovery with profile control and flooding functions have shown good application effects, they still have certain limitations. For example, Zhang Yao et al. developed a block polyether surfactant profile control and flooding system. In 2017, a field application was carried out in Well Zhou 16 area of Jianghan Oilfield. During the peak response period, the single-well output increased from 3 t / d to 8.43 t / d, and the comprehensive water cut decreased from 93.18% to 86.32%, showing a significant effect of reducing water cut and increasing oil production. However, the evaluation results showed that it only had a good profile control and flooding effect on reservoirs with a permeability variation coefficient of 3.2 - 10.9, and the profile control and flooding effect decreased significantly for reservoirs with a variation coefficient greater than 35.6; Pu Wanfen et al. developed a W / O type surfactant profile control and flooding system HC-2 with good emulsification and viscosity increasing properties. The interfacial tension can be reduced to 10 -2 mN / m. When the oil-water ratio is 7:3, it can promote the complete emulsification of the oil-water two-phase to form a high-viscosity emulsion. When the permeability variation coefficient is less than 7.5, the oil displacement efficiency can be increased by 23% - 28.77%. However, when the permeability variation coefficient is greater than 7.5, the profile control and flooding effect gradually deteriorates; Wang Yongmei et al. developed a profile control and flooding system mainly composed of anionic-nonionic surfactants and supplemented by composite anions. In 2019, a field application was carried out in the Wen 16 East block of Wenliu Oilfield. The single-well output increased from 6.2 t / d to 8.4 t / d, and the water cut decreased from 80.6% to 72.4%. However, it is a compound of multiple systems, which is prone to chromatographic separation in the reservoir and needs to be used in combination with a viscosity reducer. The system is complex and the cost is relatively high.
[0004] Therefore, it is of great significance to study and develop a surfactant that not only has high interfacial activity but also has good viscosity increasing ability for improving oil recovery. Summary of the Invention
[0005] The main object of the present invention is to provide a betaine-type surfactant, a preparation method thereof, and an application thereof, so as to solve the problem in the prior art that it is difficult for betaine-type surfactants to have both high interfacial activity and good thickening ability, resulting in low oil recovery rate in oil reservoirs.
[0006] To achieve the above object, on the one hand, the present invention provides a betaine-type surfactant, which has the structure shown in the general formula (I):
[0007]
[0008] Among them, R is an alkyl group with C8-C 24 and n takes any integer from 1 to 40.
[0009] Further, R is selected from linear or branched alkyl groups with C8-C 24 ; preferably, it is a linear alkyl group with C8-C 18 or a branched alkyl group with C 12 -C 20 .
[0010] Further, when R is a linear alkyl group with C8-C 18 , n takes any integer from 1 to 8; when R is a branched alkyl group with C 19 -C 24 , n takes any integer from 6 to 40.
[0011] Further, the betaine-type surfactant is selected from any one of the following structures:
[0012]
[0013] To achieve the above object, on the other hand, the present invention also provides a preparation method of the above betaine-type surfactant provided in the present application, and the preparation method includes:
[0014] Step S1, under the catalysis of a first catalyst, reacting an alcohol with C8-C 24 with ethylene oxide to obtain a first intermediate; the first intermediate has the structure shown in the general formula (II),
[0015]
[0016] Step S2, under the catalysis of a second catalyst and in the presence of a basic compound, reacting the first intermediate with epichlorohydrin in a first solvent to obtain a second intermediate; the second intermediate has the structure shown in the general formula (III),
[0017]
[0018] Step S3: React the second intermediate with dimethylamine in a second solvent to obtain a third intermediate; the third intermediate has the structure shown in general formula (IV).
[0019]
[0020] Step S4: React the third intermediate with 3-chloro-2-carboxypropane sulfonate in a third solvent to obtain a betaine-type surfactant; the betaine-type surfactant has the structure shown in general formula (I).
[0021]
[0022] wherein R and n have the same definitions as in the previous content respectively.
[0023] Furthermore, the temperature of the first reaction is 120 - 135 °C and the time is 4 - 7 h.
[0024] Furthermore, the molar ratio of the alcohol having C8 - C 24 to the first catalyst and ethylene oxide is 1:(0.002 - 0.02):(1 - 40).
[0025] Furthermore, the first catalyst is selected from sodium hydroxide and / or potassium hydroxide.
[0026] Furthermore, Step S2 includes: mixing the first intermediate with a second catalyst, a basic compound, and a first solvent to obtain a first mixed system; heating the first mixed system to 50 - 70 °C, and then mixing it with epichlorohydrin to obtain a second mixed system; heating the second mixed system to 85 - 110 °C and maintaining for 6 - 10 h to obtain a second intermediate.
[0027] Furthermore, the molar ratio of the first intermediate, the second catalyst, and the basic compound is 1:(0.03 - 0.06):(1.8 - 2.2).
[0028] Furthermore, the volume of the first solvent is 5 - 10 times the total volume of the first intermediate, the second catalyst, and the basic compound.
[0029] Furthermore, the molar ratio of the first intermediate to epichlorohydrin is 1:(1 - 1.2).
[0030] Furthermore, the second catalyst is tetrabutylammonium bromide.
[0031] Furthermore, the first solvent is selected from n-hexane and / or n-pentane.
[0032] Furthermore, the temperature of the third reaction is 50 - 80 °C and the time is 6 - 10 h.
[0033] Further, the volume ratio of the second intermediate to the second solvent is 1:(0.5 - 1).
[0034] Further, the molar ratio of the second intermediate to dimethylamine is 1:(1 - 1.1).
[0035] Further, the second solvent is selected from ethanol and / or isopropanol.
[0036] Further, the temperature of the fourth reaction is 50 - 90 °C and the time is 3 - 6 h.
[0037] Further, the molar ratio of the third intermediate to 3-chloro-2-carboxypropanesulfonate is 1:(1.1 - 1.3).
[0038] Further, the volume ratio of the third intermediate to the third solvent is 1:(3 - 10).
[0039] Further, the third solvent is a mixture of ethanol and water, a mixture of isopropanol and water, or a mixture of ethanol, isopropanol and water; more preferably, the third solvent is a mixture of ethanol and water with a volume ratio of 1:(1.5 - 2.5), or a mixture of isopropanol and water with a volume ratio of 1:(1.5 - 2.5).
[0040] Another aspect of the present invention provides an application of the above betaine-type surfactant provided in this application, or a betaine-type surfactant prepared by the above preparation method of the betaine-type surfactant, in the field of oilfield development.
[0041] Applying the technical solution of the present invention, in the main chain of the above betaine-type surfactant provided in this application, a specific number (n takes the above range) of repeating units -CH2-CH2-O- are introduced to increase the molecular chain length to increase the viscosity of its aqueous solution; at the same time, a carboxyl group -COO - and a sulfonic group -SO3 - are introduced at the hydrophilic tail to improve the hydrophilicity and high salt and temperature resistance of the system. The above betaine-type surfactant provided in this application not only has high interfacial activity, but also has good thickening ability, and can improve the oil reservoir recovery rate without compounding multiple surfactants. Specific Embodiments
[0042] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.
[0043] As described in the background art, existing betaine surfactants have the problem that it is difficult to have both high interfacial activity and good thickening ability, resulting in a low oil recovery rate in oil reservoirs. To solve the above technical problems, the present application provides a betaine surfactant, which has the structure shown in general formula (I):
[0044]
[0045] Among them, R is an alkyl group with C8 to C 24 and n takes any integer from 1 to 40.
[0046] For the betaine surfactant provided by the present application, a specific number (n within the above range) of repeating units -CH2-CH2-O- are introduced on the main chain of the traditional alkyl betaine surfactant molecule to increase the molecular chain length and thus increase the viscosity of its aqueous solution; at the same time, carboxyl -COO - and sulfonic group -SO3 - are introduced at the hydrophilic tail to improve the hydrophilicity and high salt and temperature resistance of the system. The betaine surfactant provided by the present application not only has high interfacial activity but also has good thickening ability, and can improve the oil recovery rate of oil reservoirs without being compounded with polymers.
[0047] In order to further improve the interfacial activity and thickening ability of the betaine surfactant, and thus further improve the oil recovery rate of oil reservoirs, R is preferably a straight-chain alkyl group with C8 to C 18 or a branched-chain alkyl group with C 12 to C 20 .
[0048] In a preferred embodiment, when R is a straight-chain alkyl group with C8 to C 18 , n takes any integer from 1 to 8; when R is a branched-chain alkyl group with C 19 to C 24 , n takes any integer from 6 to 40. Compared with other ranges, limiting both R and n within the above ranges is beneficial to further improve the interfacial activity and thickening ability of the betaine surfactant, thereby further improving the oil recovery rate of oil reservoirs.
[0049] In a preferred embodiment, the betaine surfactant includes but is not limited to any one of the following structures:
[0050]
[0051] Compared with other types, the above types of betaine surfactants have more excellent interfacial activity and thickening ability, which is beneficial to further improve the oil recovery rate of oil reservoirs.
[0052] The second aspect of the present application also provides a preparation method of the above betaine-type surfactant, and the preparation method includes: Step S1, under the catalysis of a first catalyst, reacting an alcohol with 8 to C 24 with ethylene oxide to carry out a first reaction to obtain a first intermediate; the first intermediate has the structure shown in general formula (II),
[0053]
[0054] Step S2, under the catalysis of a second catalyst and in the presence of a basic compound, reacting the first intermediate with epichlorohydrin in a first solvent to carry out a second reaction to obtain a second intermediate; the second intermediate has the structure shown in general formula (III),
[0055]
[0056] Step S3, reacting the second intermediate with dimethylamine in a second solvent to carry out a third reaction to obtain a third intermediate; the third intermediate has the structure shown in general formula (IV),
[0057]
[0058] Step S4, reacting the third intermediate with 3-chloro-2-carboxypropanesulfonate in a third solvent to carry out a fourth reaction to obtain a betaine-type surfactant; the betaine-type surfactant has the structure shown in general formula (I),
[0059]
[0060] wherein R and n have the same definitions as in the previous content respectively.
[0061] By sequentially carrying out the above first reaction, second reaction, third reaction and fourth reaction with the above reaction raw materials, a betaine-type surfactant with the structure shown in general formula (I) can be obtained. For the betaine-type surfactant prepared by the above preparation method, a specific number (n takes the above range) of repeating units -CH2-CH2-O- are introduced on the main chain of the traditional alkyl betaine surfactant molecule to increase the molecular chain length to increase the viscosity of its aqueous solution; meanwhile, a carboxyl group -COO - and a sulfonic group -SO3 - are introduced at the hydrophilic tail to improve the hydrophilicity and salt and temperature resistance of the system. The betaine-type surfactant provided by the present application not only has high interfacial activity, but also has good thickening ability, and can improve the oil reservoir recovery rate without being compounded with a polymer.
[0062] In a preferred embodiment, the temperature of the first reaction is 120 - 135 °C and the time is 4 - 7 h. The temperature and time of the first reaction include but are not limited to the above ranges. Limiting them within the above ranges is beneficial to improving the reaction efficiency of the C8 - C 24 alcohol and ethylene oxide, inhibiting side reactions, and thus beneficial to improving the formation rate of the first intermediate.
[0063] In a preferred embodiment, the molar ratio of the C8 - C 24 alcohol, the first catalyst, and ethylene oxide is 1:(0.002 - 0.02):(1 - 40). The molar ratio of the C8 - C 24 alcohol, the first catalyst, and ethylene oxide includes but is not limited to the above range. Limiting it within the above range is beneficial to improving the raw material utilization rate of the C8 - C 24 alcohol and ethylene oxide, and at the same time beneficial to improving the catalytic efficiency of the first catalyst, and thus beneficial to improving the formation rate of the first intermediate.
[0064] In a preferred embodiment, the first catalyst includes but is not limited to sodium hydroxide and / or potassium hydroxide. Compared with other types, using the above types of the first catalyst is beneficial to improving the catalytic efficiency of the first catalyst, and thus beneficial to improving the formation rate of the first intermediate.
[0065] In a preferred embodiment, step S2 includes: mixing the first intermediate with the second catalyst, the basic compound, and the first solvent to obtain a first mixed system; heating the first mixed system to 50 - 70 °C, and then mixing it with epichlorohydrin to obtain a second mixed system; heating the second mixed system to 85 - 110 °C and maintaining it for 6 - 10 h to obtain a second intermediate. Compared with directly mixing all the raw materials required in the second reaction in one step, using the above two-step mixing process provided by the present application is beneficial to improving the dispersion uniformity of each raw material in the system; at the same time, heating the second mixed system to the above temperature range and then performing the second reaction in the above time range is beneficial to improving the reaction efficiency of the second reaction and beneficial to improving the formation rate of the second intermediate.
[0066] In a preferred embodiment, the molar ratio of the first intermediate, the second catalyst, and the basic compound is 1:(0.03 - 0.06):(1.8 - 2.2). The molar ratio of the first intermediate, the second catalyst, and the basic compound includes but is not limited to the above range. Limiting it within the above range is beneficial to improving the utilization rate of the above raw materials, and at the same time beneficial to improving the dispersion uniformity of the first intermediate, and thus beneficial to improving the formation rate of the second intermediate.
[0067] In a preferred embodiment, the volume of the first solvent is 5 to 10 times the total volume of the first intermediate, the second catalyst, and the basic compound. The volume of the first solvent includes but is not limited to the above range. Limiting it within the above range is beneficial to improving the dispersibility of the above-mentioned raw materials, thereby being beneficial to increasing the formation rate of the second intermediate.
[0068] In a preferred embodiment, the molar ratio of the first intermediate to epichlorohydrin is 1:(1 - 1.2). The molar ratio of the first intermediate to epichlorohydrin includes but is not limited to the above range. Limiting it within the above range is beneficial to improving the utilization rate of raw materials, thereby being beneficial to reducing the preparation cost.
[0069] In order to further improve the catalytic efficiency of the second catalyst, and thereby further increase the formation rate of the second intermediate, preferably, the second catalyst is tetrabutylammonium bromide.
[0070] In order to further improve the dispersion uniformity of the first intermediate, and thereby further increase the formation rate of the second intermediate, preferably, the first solvent includes but is not limited to n-hexane and / or n-pentane.
[0071] In a preferred embodiment, the temperature of the third reaction is 50 - 80 °C, and the time is 6 - 10 h. The temperature and time of the third reaction include but are not limited to the above range. Limiting them within the above range is beneficial to improving the reaction efficiency of the third reaction, beneficial to suppressing the occurrence of side reactions, and thereby being beneficial to increasing the formation rate of the third intermediate.
[0072] In a preferred embodiment, the volume ratio of the second intermediate to the second solvent is 1:(0.5 - 1); the molar ratio of the second intermediate to dimethylamine is 1:(1 - 1.1). The dosage ratios of the second intermediate, dimethylamine, and the second solvent include but are not limited to the above range. Limiting them within the above range is beneficial to improving the utilization rate of the raw materials required for the third reaction, and at the same time beneficial to improving the dispersion uniformity of the second intermediate and dimethylamine in the second solvent, thereby being beneficial to increasing the formation rate of the third intermediate.
[0073] In order to further improve the dispersion uniformity of the second intermediate in the second solvent, and thereby further increase the formation rate of the third intermediate, preferably, the second solvent includes but is not limited to ethanol and / or isopropanol.
[0074] In a preferred embodiment, the temperature of the fourth reaction is 50 - 90 °C, and the time is 3 - 6 h. The temperature and time of the fourth reaction include but are not limited to the above range. Limiting them within the above range is beneficial to improving the reaction efficiency of the fourth reaction, beneficial to suppressing the occurrence of side reactions, and thereby being beneficial to increasing the formation rate and purity of the betaine-type surfactant having the structure shown in general formula (I).
[0075] In a preferred embodiment, the molar ratio of the third intermediate to 3-chloro-2-carboxypropanesulfonate is 1:(1.1 - 1.3). The molar ratio of the third intermediate to 3-chloro-2-carboxypropanesulfonate includes but is not limited to the above range. Limiting it within the above range is beneficial to improving the reaction efficiency of the fourth reaction, and thus beneficial to improving the production rate and purity of the betaine-type surfactant having the structure shown by the general formula (I).
[0076] In a preferred embodiment, the volume ratio of the third intermediate to the third solvent is 1:(3 - 10). The volume ratio of the third intermediate to the third solvent includes but is not limited to the above range. Limiting it within the above range is beneficial to improving the dispersibility of each raw material, and beneficial to improving the production rate and purity of the betaine-type surfactant.
[0077] In a preferred embodiment, the molar ratio of the third intermediate to the third solvent is 1:(3 - 10). The molar ratio of the third intermediate to the third solvent includes but is not limited to the above range. Limiting it within the above range is beneficial to improving the dispersion uniformity of the third intermediate, and thus beneficial to improving the production rate of the betaine-type surfactant having the structure shown by the general formula (I).
[0078] In a preferred embodiment, the third solvent is a mixture of ethanol and water, a mixture of isopropanol and water, or a mixture of ethanol, isopropanol and water; preferably, the third solvent is a mixture of ethanol and water with a volume ratio of 1:(1.5 - 2.5), or a mixture of isopropanol and water with a volume ratio of 1:(1.5 - 2.5). Using the above types of third solvents is beneficial to further improving the dispersion uniformity of each raw material required for the third reaction, and thus beneficial to further improving the production rate of the betaine-type surfactant.
[0079] The third aspect of the present application also provides an application of the above betaine-type surfactant, or the betaine-type surfactant prepared by the above preparation method of the betaine-type surfactant, in the field of oilfield development. The above betaine-type surfactant provided by the present application not only has high interfacial activity, but also has good thickening ability. Applying it in the field of oilfield development can significantly improve the oil reservoir recovery rate, and there is no need to compound with polymers.
[0080] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.
[0081] Example 1
[0082] A preparation method of a betaine-type surfactant, comprising:
[0083] (1) Place 1 mole of n-octanol and 0.002 mole of sodium hydroxide in a reaction kettle, introduce nitrogen to displace air in the reaction kettle for 10 min to remove the air in the reaction kettle. After passing the leak test, heat up to 120 °C. After the temperature stabilizes, inject 4 moles of ethylene oxide into the reaction kettle to carry out the first reaction. After reacting for 5 h, a first intermediate is obtained;
[0084] (2) Mix 1 mole of the first intermediate, 0.03 mole of tetrabutylammonium bromide, 2 moles of sodium hydroxide with 5 times the volume of n-hexane (the volume of n-hexane is 5 times the total volume of the first intermediate, tetrabutylammonium bromide and sodium hydroxide), heat up to 50 °C, and then slowly add 1 mole of epichlorohydrin. Heat up to 85 °C to carry out the second reaction. After reacting for 10 h, a second intermediate is obtained;
[0085] (3) Disperse 1 mole of the second intermediate in isopropanol (the volume ratio of the second intermediate to isopropanol is 1:0.5), then add 1 mole of dimethylamine, and react at 50 °C for 10 h under stirring to obtain a third intermediate;
[0086] (4) Dissolve 1 mole of 3-chloro-2-hydroxypropyl sulfonate in 5 times its volume of water, add 0.01 mole of chromium trichloride and 0.02 mole of sodium periodate, heat up to 20 °C and react for 6 h to obtain 3-chloro-2-carboxypropyl sulfonate;
[0087] (5) Mix 1 mole of the third intermediate, 1.1 moles of 3-chloro-2-carboxypropyl sulfonate with a mixed solvent (the volume ratio of the third intermediate to the mixed solvent is 1:5), where the mixed solvent is a mixture of isopropanol and water with a volume ratio of 1:5. Stir and reflux at 50 °C for 6 h to obtain a mixture containing a betaine-type surfactant, where the concentration of the betaine-type surfactant is 42.5%.
[0088] The chemical structure of the betaine-type surfactant is as follows:
[0089]
[0090] In this example, the production rate of the betaine-type surfactant is 92% and the purity is 42.5%.
[0091] Example 2
[0092] A preparation method of a betaine-type surfactant, comprising:
[0093] (1) Place 1 mole of 2-octyldodecanol and 0.02 mole of potassium hydroxide in a reaction kettle, introduce nitrogen to displace air in the reaction kettle for 10 min to remove the air in the reaction kettle. After passing the leak test, heat up to 135 °C. After the temperature stabilizes, inject 32 moles of ethylene oxide into the reaction kettle to carry out the first reaction. After reacting for 4 h, a first intermediate is obtained;
[0094] (2) Mix 1 mole part of the first intermediate, 0.06 mole part of tetrabutylammonium bromide, 2 mole parts of sodium hydroxide with 10 times the volume of n-pentane, heat up to 70 °C, and then slowly add 1.2 mole parts of epichlorohydrin, heat up to 110 °C for the second reaction, and obtain the second intermediate after reacting for 6 h;
[0095] (3) Disperse 1 mole part of the second intermediate in ethanol (the volume ratio of the second intermediate to ethanol is 1:1), then add 1.1 mole parts of dimethylamine, and react at 80 °C for 6 h under stirring to obtain the third intermediate;
[0096] (4) Dissolve 1 mole part of sodium 3-chloro-2-hydroxypropylsulfonate in 10 times its volume of water, add 0.02 mole part of chromium(III) chloride and 0.05 mole part of sodium periodate, heat up to 25 °C and react for 4 h to obtain sodium 3-chloro-2-carboxypropylsulfonate;
[0097] (5) Mix 1 mole part of the third intermediate, 1.3 mole parts of sodium 3-chloro-2-carboxypropylsulfonate with a mixed solvent (the volume ratio of the third intermediate to the mixed solvent is 1:10), wherein the mixed solvent is a mixture of ethanol and water with a volume ratio of 1:2.5, and stir and reflux at 90 °C for 3 h to obtain a mixture containing the betaine-type surfactant.
[0098] The chemical structure of the betaine-type surfactant is as follows:
[0099]
[0100] In this example, the formation rate of the betaine-type surfactant is 89.3%, and the purity is 35.4%.
[0101] Example 3
[0102] (1) Place 1 mole part of octadecanol and 0.006 mole part of sodium hydroxide in a reaction kettle, introduce nitrogen to displace for 8 min to remove the air in the reaction kettle. After passing the leak test, heat up to 125 °C. After the temperature is stable, inject 6 mole parts of ethylene oxide into the reaction kettle for the first reaction, and obtain the first intermediate after reacting for 5 h;
[0103] (2) Mix 1 mole part of the first intermediate, 0.05 mole part of tetrabutylammonium bromide, 2 mole parts of sodium hydroxide with 6 mole parts of a mixed solvent, and the mixed solvent is a mixture of n-hexane and n-pentane with a volume ratio of 1:1. Heat up to 60 °C, and then slowly add 1.1 mole parts of epichlorohydrin, heat up to 90 °C for the second reaction, and obtain the second intermediate after reacting for 8 h;
[0104] (3) Disperse 1 mole part of the second intermediate in a mixed solvent (the volume ratio of the third intermediate to the mixed solvent is 1:0.8), where the mixed solvent is a mixture of ethanol and isopropanol with a volume ratio of 1:1. Then add 1 mole part of dimethylamine and react at 70 °C for 8 h under stirring to obtain the third intermediate;
[0105] (4) Dissolve 1 mole part of sodium 3-chloro-2-hydroxypropyl sulfonate in 6 times its volume of water, add 0.015 mole part of chromium(III) chloride and 0.04 mole part of sodium periodate, heat up to 22 °C and react for 4 h to obtain sodium 3-chloro-2-carboxypropyl sulfonate;
[0106] (5) Mix 1 mole part of the third intermediate, 1.2 mole parts of sodium 3-chloro-2-carboxypropyl sulfonate with a mixed solvent (the volume ratio of the third intermediate to the mixed solvent is 1:4), where the mixed solvent is a mixture of water, ethanol and isopropanol with a volume ratio of 1:1:1, and stir and reflux at 80 °C for 4 h to obtain a mixture containing the betaine-type surfactant.
[0107] The chemical structure of the betaine-type surfactant is as follows:
[0108]
[0109] In this example, the production rate of the betaine-type surfactant is 91.7% and the purity is 39.6%.
[0110] Example 4
[0111] A preparation method of a betaine-type surfactant, comprising:
[0112] (1) Place 1 mole part of tetracosanol and 0.02 mole part of sodium hydroxide in a reaction kettle, introduce nitrogen to displace for 8 min to remove the air in the reaction kettle. After passing the leak test, heat up to 130 °C. After the temperature is stable, inject 4 mole parts of ethylene oxide into the reaction kettle for the first reaction, and react for 5 h to obtain the first intermediate;
[0113] (2) Mix 1 mole part of the first intermediate, 0.05 mole part of tetrabutylammonium bromide, 2 mole parts of sodium hydroxide and 6 mole parts of n-pentane, heat up to 60 °C, then slowly add 1 mole part of epichlorohydrin, and heat up to 85 °C for the second reaction. React for 10 h to obtain the second intermediate;
[0114] (3) Disperse 1 mole part of the second intermediate in ethanol (the volume ratio of the second intermediate to ethanol is 1:1), then add 1.05 mole parts of dimethylamine and react at 80 °C for 7 h under stirring to obtain the third intermediate;
[0115] (4) Dissolve 1 mole part of sodium 3-chloro-2-hydroxypropyl sulfonate in 8 times its volume of water, add 0.02 mole part of chromium trichloride and 0.02 mole part of sodium periodate, heat up to 22 °C and react for 4 h to obtain sodium 3-chloro-2-carboxypropyl sulfonate;
[0116] (5) Mix 1 mole part of the third intermediate, 1.3 mole parts of sodium 3-chloro-2-carboxypropyl sulfonate with a mixed solvent (the volume ratio of the third intermediate to the mixed solvent is 1:8), wherein the mixed solvent is a mixture of ethanol and water with a volume ratio of 1:2.2, stir and reflux at 90 °C for 3 h to obtain a mixture containing the betaine-type surfactant.
[0117] The chemical structure of the betaine-type surfactant is shown as follows:
[0118]
[0119] In this example, the production rate of the betaine-type surfactant is 90.8%, and the purity is 31.5%.
[0120] Example 5
[0121] The difference from Example 1 is that the ratio of raw material usage is changed, so that the chemical structure of the prepared betaine-type surfactant is shown as follows:
[0122] where R is a straight-chain alkyl group of C 40 and n is 40.
[0123] In this example, the production rate of the betaine-type surfactant is 91.3%, and the purity is 36.2%.
[0124] Example 6
[0125] The difference from Example 4 is that the ratio of raw material usage is changed, so that the chemical structure of the prepared betaine-type surfactant is shown as follows:
[0126] where R is a straight-chain alkyl group of C 24 and n is 1.
[0127] In this example, the production rate of the betaine-type surfactant is 90.5%, and the purity is 36.4%.
[0128] Comparative Example 1
[0129] The difference from Example 4 is that step (4) is not carried out, and sodium 3-chloro-2-hydroxypropyl sulfonate is directly used as a reactant to carry out the fourth reaction with the third intermediate. The remaining steps are the same as those in Example 1.
[0130] The chemical structure of the betaine-type surfactant prepared in this comparative example is shown as follows:
[0131]
[0132] In this comparative example, the production rate of the betaine-type surfactant is 89.6%, and the purity is 30.9%.
[0133] Comparative Example 2
[0134] The difference from Example 1 lies in that: a traditional betaine-type surfactant is prepared, and its chemical structure is as follows:
[0135]
[0136] Steps (1) and (2) are omitted, and octanol is directly used to replace the second intermediate and subjected to an amination reaction with dimethylamine. The amination reaction includes: 1 mole of octanol and 1 mole of dimethylamine, which are reacted at 180 °C under the catalysis of 0.2 moles of Cu to form octanolamine. The remaining steps are the same as steps (4) and (5) in Example 1.
[0137] In this comparative example, the production rate of the betaine-type surfactant is 91.8%, and the purity is 36.3%.
[0138] The betaine-type surfactants prepared in all the above examples and comparative examples of the present application are tested for interfacial tension, viscosity, emulsifying power and water solubility. The test results are shown in Table 1.
[0139] Table 1
[0140]
[0141] From the above description, it can be seen that the above examples of the present invention achieve the following technical effects: In the main chain of the traditional alkyl betaine surfactant molecule, a specific number (n takes the above range) of repeating units -CH2-CH2-O- are introduced to increase the molecular chain length to increase the viscosity of its aqueous solution; at the same time, a carboxyl group -COO - and a sulfonic group -SO3 - are introduced at the hydrophilic tail to improve the hydrophilicity and salt and temperature resistance of the system. The betaine-type surfactant provided by the present application has both high interfacial activity and good thickening ability, and can improve the oil reservoir recovery rate without being compounded with a polymer.
[0142] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those described herein.
[0143] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A betaine-type surfactant, characterized in that, The betaine surfactant has the structure shown in general formula (I): Among them, R is an alkyl group with 8 to 24 carbon atoms, and n is any integer from 1 to 40.
2. The betaine-type surfactant according to claim 1, wherein The R is selected from straight-chain or branched alkyl groups having 8 to 24 carbon atoms; preferably straight-chain alkyl groups having 8 to 18 carbon atoms or branched alkyl groups having 12 to 20 carbon atoms.
3. The betaine surfactant according to claim 1 or 2, characterized in that, When the R is a straight-chain alkyl group having 8 to C 18 , n is any integer from 1 to 8; when the R is a branched-chain alkyl group having C 19 to C 24 , n is any integer from 6 to 40.
4. The betaine surfactant according to claim 1, wherein The betaine surfactant is selected from any one of the following structures:
5. A method for preparing the betaine surfactant according to claim 1, characterized in that, The preparation method includes: Step S1, under the catalysis of a first catalyst, reacting an alcohol having 8 to C 24 with ethylene oxide in a first reaction to obtain a first intermediate; the first intermediate has a structure represented by the general formula (II), Step S2, under the catalysis of a second catalyst and in the presence of a basic compound, reacting the first intermediate with epichlorohydrin in a first solvent to carry out a second reaction to obtain a second intermediate; the second intermediate has the structure shown in general formula (III), Step S3, reacting the second intermediate with dimethylamine in a second solvent to carry out a third reaction to obtain a third intermediate; the third intermediate has the structure shown in general formula (IV), Step S4, reacting the third intermediate with 3-chloro-2-carboxypropanesulfonate in a third solvent to carry out a fourth reaction to obtain the betaine surfactant; the betaine surfactant has the structure shown in general formula (I), wherein R and n have the same definitions as in claim 1 respectively.
6. The preparation method of the betaine surfactant according to claim 5, characterized in that, The temperature of the first reaction is 120 to 135 °C and the time is 4 to 7 h; and / or, the molar ratio of the alcohol having C8 to C 24 to the first catalyst to the ethylene oxide is 1:(0.002 to 0.02):(1 to 40); Preferably, the first catalyst is selected from sodium hydroxide and / or potassium hydroxide.
7. The preparation method of the betaine surfactant according to claim 5 or 6, characterized in that, The step S2 includes: Mixing the first intermediate with the second catalyst, the basic compound and the first solvent to obtain a first mixed system; heating the first mixed system to 50-70 °C, and then mixing it with the epichlorohydrin to obtain a second mixed system; heating the second mixed system to 85-110 °C and maintaining for 6-10 h to obtain the second intermediate; Preferably, the molar ratio of the first intermediate, the second catalyst to the basic compound is 1:(0.03-0.06):(1.8-2.2); Preferably, the volume of the first solvent is 5-10 times the total volume of the first intermediate, the second catalyst and the basic compound; Preferably, the molar ratio of the first intermediate to the epichlorohydrin is 1:(1-1.2); Preferably, the second catalyst is tetrabutylammonium bromide; Preferably, the first solvent is selected from n-hexane and / or n-pentane.
8. The preparation method of the betaine-type surfactant according to any one of claims 5 to 7, characterized in that, The temperature of the third reaction is 50-80 °C and the time is 6-10 h; and / or, the volume ratio of the second intermediate to the second solvent is 1:(0.5-1); and / or, the molar ratio of the second intermediate to the dimethylamine is 1:(1-1.1); Preferably, the second solvent is selected from ethanol and / or isopropanol.
9. The preparation method of the betaine-type surfactant according to claim 8, characterized in that, The temperature of the fourth reaction is 50-90 °C and the time is 3-6 h; and / or, the molar ratio of the third intermediate to the 3-chloro-2-carboxypropanesulfonate is 1:(1.1-1.3); and / or, the volume ratio of the third intermediate to the third solvent is 1:(3-10); Preferably, the third solvent is a mixture of ethanol and water, a mixture of isopropanol and water, or a mixture of ethanol, isopropanol and water; more preferably, the third solvent is a mixture of ethanol and water with a volume ratio of 1:(1.5-2.5), or a mixture of isopropanol and water with a volume ratio of 1:(1.5-2.5).
10. Application of the betaine-type surfactant according to any one of claims 1 to 4, or the betaine-type surfactant prepared by the preparation method of the betaine-type surfactant according to any one of claims 5 to 9, in the field of oilfield development.