Amine oxide emulsifier as well as preparation method and application thereof
The amine oxide emulsifier prepared by amidation and oxidation reactions solves the problems of poor biodegradability and insufficient high-temperature stability of sulfonic acid emulsifiers, and achieves efficient oil-water interface stability and environmentally friendly emulsification performance.
Patent Information
- Application Number
- CN202511746003.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-25
- Publication Date
- 2026-02-27
AI Technical Summary
Existing sulfonic acid emulsifiers use highly corrosive sulfonating agents in their preparation process, resulting in poor biodegradability, easy environmental pollution, and insufficient demulsification voltage at high temperatures, making it difficult to maintain stability in saline environments.
An amine oxide emulsifier was prepared by amidation of maleic acid-modified long-chain fatty acids and aliphatic dimethyl diamine, followed by oxidation with hydrogen peroxide aqueous solution. The long-chain structure and amide bond characteristics were used to improve biodegradability and high-temperature resistance. Furthermore, the emulsifier formed a stable interfacial layer with water molecules through hydrogen bonds, thereby reducing interfacial tension.
The prepared amine oxide emulsifier has good biodegradability and high demulsification voltage. It can maintain stable water-in-oil emulsions in high temperature and saline environments, reduce interfacial tension, form stable emulsions, and reduce environmental pollution.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of petroleum chemical industry, and particularly relates to an amine oxide emulsifier, a preparation method and application thereof. BACKGROUND
[0002] Oil-based drilling fluid is a multiphase system formed by stably dispersing water phase (fresh water or salt water) and solid particles through an emulsifier with oil (diesel oil, mineral oil or crude oil) as a continuous phase. The emulsifier is a core treatment agent for maintaining the stability and functionality of the oil-based drilling fluid. At present, the commonly used oil-based drilling fluid emulsifier is a sulfonic acid emulsifier, which has excellent emulsifying performance and salt resistance, is less affected by pH value, and the oil-based drilling fluid prepared therefrom has a demulsification voltage of more than 900V at 200℃, and good high-temperature resistance. However, a strong corrosive sulfonating agent (such as chlorosulfonic acid) is often used in the preparation process of the sulfonic acid emulsifier, which is corrosive and toxic to organisms, and the sulfonated emulsifier obtained therefrom has poor biodegradability and easily causes environmental pollution. SUMMARY
[0003] The present application provides an amine oxide emulsifier, a preparation method and application thereof, and the amine oxide emulsifier provided by the present application has good biodegradability.
[0004] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: The present application provides a preparation method of an amine oxide emulsifier, comprising the following steps: Maleated long-chain fatty acid and aliphatic dimethyl diamine are mixed and then subjected to amidation to obtain an amine oxide emulsifier precursor; The amine oxide precursor, isopropyl alcohol and hydrogen peroxide aqueous solution are mixed and then subjected to oxidation reaction to obtain an amine oxide emulsifier.
[0005] Preferably, the mass ratio of the maleated long-chain fatty acid to the aliphatic dimethyl diamine is (1-2):1.
[0006] Preferably, the maleated long-chain fatty acid comprises maleated tall oil fatty acid, maleated coconut oil fatty acid or maleated ricinoleic acid.
[0007] Preferably, the temperature of the amidation is 150-160℃, and the time of the amidation is 4-6h.
[0008] Preferably, the mass ratio of the amine oxide precursor to isopropyl alcohol is 1:(1-4).
[0009] Preferably, the mass ratio of the amine oxide precursor to hydrogen peroxide in the hydrogen peroxide aqueous solution is (5-10):1.
[0010] Preferably, the mass fraction of hydrogen peroxide in the aqueous hydrogen peroxide solution is 20-30%.
[0011] Preferably, the temperature of the oxidation reaction is 48-52℃, and the time of the oxidation reaction is 3-5h.
[0012] The present application also provides the amine oxide emulsifier prepared by the preparation method.
[0013] The present application also provides the amine oxide emulsifier prepared by the preparation method or the application of the amine oxide emulsifier in the oil-based drilling fluid.
[0014] The present application provides a preparation method of an amine oxide emulsifier, comprising the following steps: mixing the maleated long-chain fatty acid with aliphatic dimethyl diamine to perform amidation, to obtain an amine oxide emulsifier precursor; mixing the amine oxide precursor, isopropyl alcohol and an aqueous hydrogen peroxide solution to perform oxidation reaction, to obtain the amine oxide emulsifier. The long-chain structure of the long-chain fatty acid in the maleated long-chain fatty acid is convenient for enzyme recognition and step-by-step cutting, so as to improve the biodegradability of the amine oxide emulsifier; the maleated modification improves the molecular rigidity of the long-chain fatty acid, and further improves the emulsifier strength and high-temperature resistance; then the aliphatic dimethyl diamine and the maleated long-chain fatty acid are subjected to amidation to obtain the amine oxide emulsifier precursor, the carbon-nitrogen bond in the amide bond in the amine oxide emulsifier precursor has partial double bond characteristics, the bond energy is higher, the rotation is blocked, and the hydrolysis rate of the amide bond under acidic or alkaline conditions is much lower than that of the ester bond and the carboxyl group, so the amine oxide emulsifier has good high-temperature resistance; and the amide bond is a strong hydrogen bond acceptor (carbonyl oxygen) and a strong hydrogen bond donor (imino), so even in a salt water environment, they can form stable hydrogen bonds with the H and OH of the water molecules, and have good salt tolerance; and a tertiary amine group is provided for the preparation of the amine oxide emulsifier; finally, the aqueous hydrogen peroxide solution is used to oxidize the amine oxide emulsifier precursor to obtain the amine oxide emulsifier, which has small toxicity and small influence on aquatic organisms; and the aqueous hydrogen peroxide solution is used to oxidize the raw material to obtain the amine oxide emulsifier, which can spontaneously migrate and be adsorbed on the oil-water interface, replace the original water-oil high-energy interface with the two low-energy interfaces of “water-amine oxide hydrophilic head group” and “amine oxide hydrophobic tail-oil”, reduce the total energy required to maintain the interface, and macroscopically show a significant decrease in interfacial tension; and the amine oxide emulsifier has strong hydrogen bonds and dipole effects, can form an extremely firm hydration layer with water molecules, greatly stabilizes the water phase side at the interface, and even at high temperatures, the amine oxide molecules can be stably adsorbed on the oil-water interface to reduce the interfacial tension and form a stable W / O emulsion, so the amine oxide emulsifier is very stable in a salt-containing or hard water system and is not easy to break. The results of the examples show that the amine oxide emulsifier provided by the present application has an LC50 of 42300 mg / L, a BOD5 of 71403 mg / L and a COD of 0.5 mg / L.cr is 217660mg / L, and is easy to degrade; the demulsification voltage can reach 1262V, and the emulsification rate can reach 98.2%. DETAILED DESCRIPTION
[0015] The application provides a preparation method of an amine oxide emulsifier, comprising the following steps: The amine oxide emulsifier precursor is obtained by mixing maleated long-chain fatty acid and aliphatic dimethyl diamine and then performing amidation. The amine oxide emulsifier is obtained by mixing the amine oxide precursor, isopropyl alcohol and hydrogen peroxide solution and then performing oxidation reaction.
[0016] The amine oxide emulsifier precursor is obtained by mixing maleated long-chain fatty acid and aliphatic dimethyl diamine and then performing amidation.
[0017] As an embodiment of the application, the maleated long-chain fatty acid can be maleated tall oil fatty acid, maleated coconut oil fatty acid or maleated ricinoleic acid. The long-chain structure of the long-chain fatty acid in the maleated long-chain fatty acid is convenient for enzyme recognition and step-by-step cutting, so that the biodegradability of the amine oxide emulsifier is improved; the natural carbon chain diversity makes the emulsifier prepared therefrom adapt to oil phases of different polarity, and the emulsifier is suitable for various oil-based drilling fluid systems; and the maleated long-chain fatty acid is obtained by modifying long-chain fatty acid with maleic anhydride, so that the molecular rigidity of the long-chain fatty acid is improved, and the strength and high-temperature resistance of the emulsifier are improved.
[0018] The application is not specially limited to the preparation method of the maleated long-chain fatty acid, and the preparation method commonly used in the art can be adopted. As an embodiment of the application, the preparation method of the maleated long-chain fatty acid can be: mixing long-chain fatty acid with maleic anhydride and then performing esterification reaction to obtain maleated long-chain fatty acid.
[0019] As an embodiment of the application, the temperature of the esterification reaction can be 180-200℃. As an embodiment of the application, the time of the esterification reaction can be 8-10h.
[0020] As an embodiment of the application, the aliphatic dimethyl diamine can be N,N-dimethylpropylene diamine, N,N-dimethyl-1,4-butanediamine or N,N-dimethyl-1,2-ethanediamine. By limiting the aliphatic dimethyl diamine to perform amidation with the maleated long-chain fatty acid, the temperature resistance and salt resistance of the emulsifier can be improved, and a tertiary amine group is provided for preparation of the amine oxide emulsifier.
[0021] As an embodiment of the present application, the mass ratio of the maleated long chain fatty acid to the aliphatic dimethyl diamine can be (1-2):1. In an embodiment of the present application, the mass ratio of the maleated long chain fatty acid to the aliphatic dimethyl diamine can be specifically 1:1, 1.5:1 or 2:1. The present application limits the mass ratio of the maleated long chain fatty acid to the aliphatic dimethyl diamine to the above range to ensure more sufficient amidation of the maleated long chain fatty acid and the aliphatic dimethyl diamine.
[0022] The present application does not have special limitation on the mixing of the maleated long chain fatty acid and the aliphatic dimethyl diamine, and any mixing method known in the art can be used.
[0023] As an embodiment of the present application, the temperature of the amidation can be 150-160°C. In an embodiment of the present application, the temperature of the amidation can be specifically 150°C, 152°C, 154°C, 156°C, 158°C or 160°C. As an embodiment of the present application, the time of the amidation can be 4-6h. In an embodiment of the present application, the time of the amidation can be specifically 4h, 5h or 6h. As an embodiment of the present application, the amidation can be carried out under nitrogen atmosphere. The present application sets the parameters of the amidation to the above range to ensure more sufficient amidation reaction.
[0024] After the amidation is completed, the present application preferably distills the product of the amidation under reduced pressure to obtain an amine oxide emulsifier precursor.
[0025] The present application does not have special limitation on the method of the distillation under reduced pressure, and any distillation under reduced pressure method known in the art can be used to remove water from the product of the amidation.
[0026] After the amine oxide emulsifier precursor is obtained, the present application mixes the amine oxide emulsifier precursor, isopropyl alcohol and hydrogen peroxide aqueous solution to carry out oxidation reaction to obtain an amine oxide emulsifier.
[0027] As an embodiment of the present application, the mass ratio of the amine oxide emulsifier precursor to the isopropyl alcohol can be 1:(1-4). In an embodiment of the present application, the mass ratio of the amine oxide emulsifier precursor to the isopropyl alcohol can be specifically 1:1, 1:2, 1:3 or 1:4. The present application limits the mass ratio of the amine oxide emulsifier precursor to the isopropyl alcohol to the above range to ensure sufficient dissolution of the amine oxide emulsifier precursor and control the concentration of the amine oxide emulsifier precursor and the reaction rate.
[0028] As an embodiment of the present application, the mass fraction of hydrogen peroxide in the aqueous hydrogen peroxide solution can be 20-30%. In the embodiments of the present application, the mass fraction of hydrogen peroxide in the aqueous hydrogen peroxide solution can be specifically 20%, 25% or 30%. The present application controls the oxidation reaction process and avoids the generation of by-products by limiting the mass fraction of hydrogen peroxide in the aqueous hydrogen peroxide solution.
[0029] As an embodiment of the present application, the mass ratio of the amine oxide emulsifier precursor to hydrogen peroxide in the aqueous hydrogen peroxide solution can be (5-10):1. In the embodiments of the present application, the mass ratio of the amine oxide emulsifier precursor to hydrogen peroxide in the aqueous hydrogen peroxide solution can be specifically 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1. The present application limits the mass ratio of the amine oxide emulsifier precursor to hydrogen peroxide in the aqueous hydrogen peroxide solution to the above range to ensure that the chemical equilibrium and reaction rate of the oxidation reaction are in a controllable range, thereby improving the purity of the prepared amine oxide emulsifier.
[0030] As an embodiment of the present application, the mixing of the amine oxide emulsifier precursor, isopropyl alcohol and aqueous hydrogen peroxide solution can be mixing the amine oxide emulsifier precursor and isopropyl alcohol to obtain a mixed solution, and then mixing the mixed solution with the aqueous hydrogen peroxide solution. As an embodiment of the present application, the mixing of the amine oxide emulsifier precursor and isopropyl alcohol can be carried out under stirring. As an embodiment of the present application, the stirring rate can be 50-200 rpm. As an embodiment of the present application, the mixing of the mixed solution and the aqueous hydrogen peroxide solution can be dropwise adding the aqueous hydrogen peroxide solution to the mixed solution. As an embodiment of the present application, the dropwise adding rate can be 1-2 mL / min. In the embodiments of the present application, the dropwise adding rate can be specifically 1 mL / min, 1.5 mL / min or 2 mL / min.
[0031] In the present application, the nitrogen atom of the tertiary amine in the amine oxide precursor attacks hydrogen peroxide in the oxidation reaction, goes through an unstable charged intermediate, loses a water molecule through proton transfer and bond cleavage, and finally forms an amine oxide. As an embodiment of the present application, the temperature of the oxidation reaction can be 48-52℃. In the embodiments of the present application, the temperature of the oxidation reaction can be specifically 48℃, 49℃, 50℃, 51℃ or 52℃. As an embodiment of the present application, the time of the oxidation reaction can be 3-5 h. In the embodiments of the present application, the time of the oxidation reaction can be specifically 3 h, 4 h or 5 h. The present application sets the parameters of the oxidation reaction in the above range to ensure that no by-reaction is generated and the prepared amine oxide has high purity.
[0032] After the completion of the oxidation reaction, the present application performs vacuum distillation on the product after the oxidation reaction to obtain an amine oxide emulsifier.
[0033] The present application does not have special restrictions on the manner of the reduced pressure distillation, and the water and isopropanol in the amidated product can be removed by using a reduced pressure distillation manner known in the art.
[0034] The present application also provides an amine oxide emulsifier prepared by the preparation method.
[0035] The present application also provides the amine oxide emulsifier prepared by the preparation method or the application of the amine oxide emulsifier in an oil-based drilling fluid.
[0036] The amine oxide emulsifier provided by the present application has good emulsification, high temperature resistance and good biodegradability when applied in an oil-based drilling fluid.
[0037] The technical solutions in the present application will be clearly and completely described below with reference to the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.
[0038] Embodiment 1 A preparation method of an amine oxide emulsifier is as follows: Maleated tall oil fatty acid is mixed with 20 parts by mass of N,N-dimethylpropylene diamine, and then amidated at 150℃ under a nitrogen atmosphere for 4h, and then reduced pressure distillation is performed at 150℃ and 0.01MPa to obtain a light yellow viscous liquid amine oxide emulsifier precursor; The amine oxide precursor and 100 parts of isopropanol are mixed at 100rpm, and then 20 parts of a 30% mass concentration hydrogen peroxide aqueous solution is added dropwise at 1mL / min, and then mixed and oxidized at 50℃ (with an ice water bath for temperature control) for 3h, and then reduced pressure distillation is performed at 100℃ and 0.01MPa to obtain the amine oxide emulsifier; the mass ratio of the maleated tall oil fatty acid to the N,N-dimethylpropylene diamine is 1:1; and the mass ratio of the amine oxide precursor to the isopropanol is 1:4; The preparation method of the maleated tall oil fatty acid is: under oil bath condition, 40 parts of tall oil fatty acid is added into a three-necked flask, heated to 140℃, air is introduced for 30 min, then heated to 200℃, 20 parts of maleic anhydride is added, and reaction is carried out for 8 h under stirring condition of 200 rpm to obtain the maleated tall oil fatty acid.
[0039] Example 2 A preparation method of an amine oxide emulsifier is: The maleated tall oil fatty acid is mixed with 10 parts of N,N-dimethylpropylene diamine, then amidated at 160℃ under nitrogen atmosphere for 5 h, and then distilled under reduced pressure at 160℃ and 0.01 MPa to obtain the amine oxide emulsifier precursor in light yellow viscous liquid; The amine oxide precursor and 120 parts of isopropanol are mixed under 50 rpm, then 10 parts of hydrogen peroxide aqueous solution with mass concentration of 30% is added dropwise at 2 mL / min, and then mixed and oxidized at 50℃ (temperature is controlled by ice water bath) for 4 h, and then distilled under reduced pressure at 90℃ and 0.01 MPa to obtain the amine oxide emulsifier; the mass ratio of the maleated tall oil fatty acid to N,N-dimethylpropylene diamine is 1.5:1; the mass ratio of the amine oxide precursor to isopropanol is 1:1; The preparation method of the maleated tall oil fatty acid is: under oil bath condition, 70 parts of tall oil fatty acid is added into a three-necked flask, heated to 160℃, air is introduced for 50 min, then heated to 180℃, 10 parts of maleic anhydride is added, and reaction is carried out for 9 h under stirring condition of 100 rpm to obtain the maleated tall oil fatty acid.
[0040] Example 3 A preparation method of an amine oxide emulsifier is: The maleated tall oil fatty acid is mixed with 15 parts of N,N-dimethylpropylene diamine, then amidated at 155℃ under nitrogen atmosphere for 6 h, and then distilled under reduced pressure at 155℃ and 0.01 MPa to obtain the amine oxide emulsifier precursor in light yellow viscous liquid; The amine oxide precursor and 150 parts of isopropanol are mixed under 200 rpm, then 15 parts of hydrogen peroxide aqueous solution with mass concentration of 30% is added dropwise at 2 mL / min, and then mixed and oxidized at 50℃ (temperature is controlled by ice water bath) for 3 h, and then distilled under reduced pressure at 80℃ and 0.01 MPa to obtain the amine oxide emulsifier; the mass ratio of the maleated tall oil fatty acid to N,N-dimethylpropylene diamine is 2:1; the mass ratio of the amine oxide precursor to isopropanol is 1:2; The preparation method of the maleated tall oil fatty acid is: under oil bath condition, 60 parts of tall oil fatty acid is added into a three-necked flask, heated to 150℃, air is introduced for 40 min, then heated to 190℃, 10 parts of maleic anhydride is added, and reacted for 10 h under the condition of stirring at 50 rpm to obtain the maleated tall oil fatty acid.
[0041] Example 4 A preparation method of an amine oxide emulsifier is: The maleated tall oil fatty acid is mixed with 15 parts of N,N-dimethylpropylene diamine, then amidated at 160℃ under nitrogen atmosphere for 4 h, and then distilled under reduced pressure at 160℃ and 0.01 MPa to obtain a light yellow viscous liquid amine oxide emulsifier precursor; The amine oxide precursor and 100 parts of isopropanol are mixed at 100 rpm, then 20 parts of hydrogen peroxide aqueous solution with a mass concentration of 30% is added dropwise at 1 mL / min, and then mixed and oxidized at 50℃ (with the aid of ice water bath for temperature control) for 5 h, and then distilled under reduced pressure at 100℃ and 0.01 MPa to obtain the amine oxide emulsifier; the mass ratio of the maleated tall oil fatty acid to N,N-dimethylpropylene diamine is 1.5:1; the mass ratio of the amine oxide precursor to isopropanol is 1:3; The preparation method of the maleated tall oil fatty acid is: under oil bath condition, 60 parts of tall oil fatty acid is added into a three-necked flask, heated to 150℃, air is introduced for 40 min, then heated to 190℃, 10 parts of maleic anhydride is added, and reacted for 10 h under the condition of stirring at 50 rpm to obtain the maleated tall oil fatty acid.
[0042] According to GB / T18420.2-2009 “Marine Oil Exploration and Development Pollutant Biological Toxicity” Part 2: Test Method, the biological toxicity of the emulsifiers prepared in Examples 1-4 and sodium dodecyl benzene sulfonate (SDBS) (Araladin Reagent (Shanghai) Co., Ltd.) is tested; and according to SY / T6788-2020 “Water-soluble Oil Field Chemical Environmental Protection Technology Evaluation Requirements” Example 1-4, the biodegradability of the emulsifiers prepared in Examples 1-4 and sodium dodecyl benzene sulfonate (SDBS) (Araladin Reagent (Shanghai) Co., Ltd.) is evaluated, and the data is shown in Table 1.
[0043] Table 1 Biological toxicity and biodegradability related data table of the emulsifiers prepared in Examples 1-4 and sodium dodecyl benzene sulfonate
[0044] As shown in Table 1, the amine oxide emulsifier LC50 prepared in Examples 1-4 is 38200-42300; the sodium dodecyl benzene sulfonate emulsifier LC50 is 10850, indicating that the amine oxide emulsifier prepared in Examples 1-4 has small biological toxicity; the BOD5 of the amine oxide emulsifier prepared in Examples 1-4 is 60945-71403 mg / L, and the CODcr is 217660-246217 mg / L, the BOD5 of the sodium dodecyl benzene sulfonate is 35379 mg / L, and the CODcr is 321545 mg / L, indicating that, compared with the sodium dodecyl benzene sulfonate, the amine oxide emulsifier prepared in the application has good biodegradability and low environmental pollution degree.
[0045] The emulsifying performance and high temperature resistance of the emulsifier prepared in Examples 1-4 and the sodium dodecyl benzene sulfonate are tested according to the method specified in the enterprise standard Q / SH35800047-2016 “Low oil-water ratio oil-based drilling fluid emulsifier SMEMUL technical requirements” of SINOPEC Research Institute of Petroleum Engineering, and the specific method is as follows: Preparation of emulsion: 300 mL diesel oil is taken in a 1000 mL high-speed stirring cup, and then 16.0 g of the emulsifier prepared in Examples 1-4 and the sodium dodecyl benzene sulfonate emulsifier are taken respectively, stirred at a speed of 10000 r / min, and then 4.0 g of auxiliary emulsifier (Span-80) is added and stirred for 30 min, 100 mL of calcium chloride solution (26% of calcium chloride mass percentage concentration) is added at a rate of 50 mL / min, and stirred for 20 min; then 10.0 g of calcium oxide and 12.0 g of high-temperature resistant organic bentonite are added, and stirring is continued for 60 min, and the mixture is hot-rolled in a roller furnace at a temperature of 200 ℃ for 16 h, and then cooled to room temperature, and the demulsification voltage is tested; then, the emulsion is poured into a 100 ml graduated cylinder after stirring at a speed of 10000 r / min for 10 min, and left to stand at room temperature for 24 h, and the emulsification rate (R) is calculated, and the calculation formula is R=(100-V) / 100x100%; wherein: R is the emulsification rate, %; V is the volume of the separated oil layer of the emulsion, mL; and the demulsification voltage and the emulsification rate are shown in Table 2.
[0046] Table 2 Data table of demulsification voltage and emulsification rate of the emulsifier prepared in Examples 1-4 and the sodium dodecyl benzene sulfonate
[0047] As shown in Table 2, the demulsification voltage of the drilling fluid to which the amine oxide emulsifier prepared in Examples 1-4 is applied is 1171-1262V; the demulsification voltage of the drilling fluid to which the sodium dodecyl benzene sulfonate emulsifier is applied is 678V; it is indicated that the amine oxide emulsifier prepared in Examples 1-4 has good emulsification performance when applied to the drilling fluid; the emulsification rate of the drilling fluid to which the amine oxide emulsifier prepared in Examples 1-4 is applied is 97.5-98.2%; the emulsification rate of the drilling fluid to which the sodium dodecyl benzene sulfonate emulsifier is applied is 81.5%, it is indicated that the amine oxide emulsifier prepared in Examples 1-4 has high emulsification rate at 200℃ when applied to the drilling fluid.
[0048] As summarized above, the amine oxide emulsifier provided by the present application has good biodegradability, and has good emulsification performance and high temperature resistance when applied to the drilling fluid.
[0049] The above only describes the preferred embodiments of the present application, and it should be noted that the ordinary skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.
Claims
1. A method for preparing an amine oxide emulsifier, comprising the following steps: mixing maleated long chain fatty acid with aliphatic dimethyl diamine, and then carrying out amidation to obtain an amine oxide emulsifier precursor; mixing the amine oxide precursor, isopropanol and hydrogen peroxide aqueous solution, and then carrying out oxidation reaction to obtain the amine oxide emulsifier. The mass ratio of the maleated long chain fatty acid to the aliphatic dimethyl diamine is (1-2) :
1. The maleated long chain fatty acid comprises maleated tall oil fatty acid, maleated coconut oil fatty acid or maleated ricinoleic acid.
2. The production method according to claim 1, characterized by, The temperature of the amidation is 150-160℃, and the time of the amidation is 4-6h.
3. The production method according to claim 1 or 2, characterized by, The mass ratio of the amine oxide precursor to isopropanol is 1: (1-4).
4. The production method according to claim 1, characterized by, The mass ratio of the amine oxide precursor to hydrogen peroxide in the hydrogen peroxide aqueous solution is (5-10) :
1.
5. The preparation method according to claim 1, characterized in that, The mass fraction of hydrogen peroxide in the hydrogen peroxide aqueous solution is 20-30%.
6. The method of claim 1, wherein, The temperature of the oxidation reaction is 48-52℃, and the time of the oxidation reaction is 3-5h.
7. The production method according to claim 1 or 6, characterized by, 9.The amine oxide emulsifier prepared by the method of any one of claims 1-8.
8. The method of claim 1, wherein, 10.The application of the amine oxide emulsifier prepared by the method of any one of claims 1-8 or the amine oxide emulsifier of claim 1 in oil-based drilling fluid.