Ionic liquid, preparation method therefor and use thereof

Abstract

Provided in the present application are an ionic liquid, a preparation method therefor and the use thereof. The ionic liquid comprises a structural formula of formula 1, wherein R1 and R2 are each independently selected from C8-C18 alkyl, and n is an integer from 0 to 3. The ionic liquid provided in the present application, as a demulsifier, is applied to demulsification of crude oil emulsions, has the advantages of high demulsification efficiency, low usage amount, low demulsification temperature, etc. and has excellent demulsification effects under high salt content conditions.

Description

Ionic liquid and preparation method and application thereof

[0001] The present application claims priority to the Chinese patent application No. 2024113187147, filed on September 20, 2024, and entitled "Ionic liquid and preparation method and application thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application belongs to the technical field of oil field chemical additives, and specifically relates to an ionic liquid and a preparation method and application thereof. BACKGROUND

[0003] In the process of oil field exploitation, with the implementation of steam flooding, surfactant, polymer and ternary compound flooding oil recovery technology, the water content of crude oil emulsion increases, and the stability is enhanced, and the difficulty of crude oil demulsification is increased. The formation of emulsion will bring a series of serious harm to the exploitation, transportation and processing of oil. The emulsification of crude oil and water will increase the difficulty of oil exploitation, and increase the load of pump and transportation cost when transporting water-containing crude oil by pipeline or tank truck.

[0004] The methods of crude oil demulsification mainly include chemical method, electric method, centrifugal separation method, ultrasonic method and biological method. Among them, the chemical method and the electric method are most commonly used, but the electric method has higher requirements for equipment and process conditions, and the implementation is more complex, the initial investment and the running cost are both high, and the chemical method is an economic and reasonable method. At present, the commercial demulsifier has poor effect on crude oil demulsification, high demulsification temperature and large amount of demulsifier. And the skilled person has researched the demulsifier, Guo Donghong et al. synthesized a natural high molecular demulsifier with polyether branch structure by using xanthan gum or guar gum as starting agent and adding ethylene oxide and propylene oxide, and simply evaluated the demulsification performance thereof; Xu et al. found that ethyl cellulose can effectively remove 90% of water in asphalt emulsion, and systematically studied the demulsification mechanism thereof; Fan et al. synthesized a series of chitosan crude oil demulsifiers, which have certain demulsification and dehydration effect on water-in-oil (W / O) crude oil emulsion under the condition of demulsification temperature of 60 DEG C, and discussed the demulsification mechanism thereof; CN101255354A developed a non-polyether type heavy oil demulsifier and a preparation method thereof, which is prepared by copolymerization of butyl acrylate and acrylic acid; CN102399576A disclosed a new type of crude oil demulsifier and a preparation method thereof, which is esterified by butyl acrylate acrylic copolymer and polyether type demulsifier, but the demulsifiers prepared by the above researches have problems of low demulsification efficiency, large amount of use, high demulsification temperature, poor demulsification effect under high salt condition, etc.

[0005] Therefore, the skilled person in the art urgently needs to develop a demulsifier with low usage amount, high demulsification efficiency, low demulsification temperature and high salt resistance. SUMMARY

[0006] The application provides an ionic liquid which is used as a demulsifier in crude oil emulsion demulsification, has high demulsification efficiency, low use amount, low demulsification temperature and the like, and excellent demulsification effect under high salt conditions.

[0007] The application provides a demulsifier which can demulsify crude oil emulsion with high efficiency, and has low use amount, low demulsification temperature and high salt resistance.

[0008] The application provides a crude oil emulsion demulsification method, and the demulsifier can demulsify crude oil emulsion with high efficiency, low use amount, low demulsification temperature and high salt resistance.

[0009] The application provides an ionic liquid, wherein the ionic liquid comprises a structural formula of formula 1.

[0010] wherein R1 and R2 are each independently selected from C8-C18 alkyl, and n is an integer from 0 to 3.

[0011] The ionic liquid as described above is prepared by the following steps.

[0012] The alkyl phenol, formaldehyde and the polyamine are subjected to a first reaction to obtain a first product with a structural formula of formula 2, the long-chain alkyl dimethyl tertiary amine is subjected to a second reaction with epichlorohydrin to obtain a second product with a structural formula of formula 3, and then the first product and the second product are subjected to a third reaction to obtain the ionic liquid.

[0013] The application provides a preparation method of the ionic liquid as described above, comprising the following steps.

[0014] 1) the alkyl phenol, formaldehyde and the polyamine are subjected to a first reaction to obtain a first product with a structural formula of formula 2:

[0015] 2) the long-chain alkyl dimethyl tertiary amine is subjected to a second reaction with epichlorohydrin to obtain a second product with a structural formula of formula 3:

[0016] 3) the first product and the second product are subjected to a third reaction to obtain the ionic liquid.

[0017] The preparation method of the ionic liquid as described above, wherein step 1) comprises the following steps.

[0018] After the alkyl phenol and the polyamine are uniformly mixed, the formaldehyde is added dropwise and reacted for 0.5-2 hours, and then a solvent is added to obtain the first product;

[0019] wherein the reaction temperature of the first reaction is 80-120°C, and the reaction time is 5-16h.

[0020] The method for preparing the ionic liquid as described above, wherein step 2) comprises the following steps:

[0021] The long-chain alkyl dimethyl tertiary amine is dissolved in a solvent, and then the epichlorohydrin is added dropwise, and the second reaction is carried out to obtain the second product;

[0022] wherein the reaction temperature of the second reaction is 25-40°C, and the reaction time is 5-16h.

[0023] The method for preparing the ionic liquid as described above, wherein step 3) comprises the following steps:

[0024] The first product and the second product are dissolved in a solvent, and then the third reaction is carried out to obtain the ionic liquid;

[0025] wherein the reaction temperature of the third reaction is 60-120°C, and the reaction time is 5-16h.

[0026] The method for preparing the ionic liquid as described above, wherein the molar ratio of the alkyl phenol, formaldehyde, and polyamine is 1:(1.5-2.5):(1.5-2.5);

[0027] and / or, the molar ratio of the long-chain alkyl dimethyl tertiary amine and epichlorohydrin is 1:1;

[0028] and / or, the molar ratio of the first product and the second product is 1:2.

[0029] The method for preparing the ionic liquid as described above, wherein the alkyl phenol comprises one or more of 4-octyl phenol, 4-dodecyl phenol, 4-tetradecyl phenol, 4-hexadecyl phenol, and 4-octadecyl phenol;

[0030] and / or, the polyamine comprises at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine;

[0031] and / or, the long-chain alkyl dimethyl tertiary amine comprises at least one of octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, and octadecyl dimethyl tertiary amine;

[0032] and / or, the solvent comprises at least one of methanol, ethanol, tetrahydrofuran, acetone, dioxane, toluene, and xylene.

[0033] The present application provides a demulsifier comprising the ionic liquid as described above.

[0034] The application provides a crude oil emulsion demulsification method, comprising the following steps: demulsifying the crude oil emulsion by using the demulsifier.

[0035] The ion liquid provided by the application has a specific structural formula, has multiple hydrophobic structures, and shows amphiphilicity and high interfacial activity. The ion liquid can be quickly adsorbed to an oil-water interface, greatly reduces interfacial tension, softens or destroys an interfacial film, thereby reducing the stability of the interfacial film, promoting the occurrence of a demulsification process, and further enabling the ion liquid to efficiently demulsify at a low usage amount.

[0036] In the preparation method of the ion liquid provided by the application, the alkyl phenol, formaldehyde and polyamine are subjected to grafting reaction to prepare a first product, then long-chain alkyl dimethyl tertiary amine is subjected to ionization reaction with epichlorohydrin to prepare a second product, and finally the first product and the second product are subjected to ring-opening reaction to obtain the ion liquid. Through the preparation method, the ion liquid can have multiple hydrophobic chains, so that the ion liquid shows amphiphilicity and high interfacial activity, and further has high demulsification efficiency, low usage amount, low demulsification temperature and high salt resistance.

[0037] The application further provides a demulsifier which can efficiently demulsify crude oil emulsion, has low usage amount, low demulsification temperature, and high salt resistance.

[0038] The application provides a crude oil emulsion demulsification method. The demulsifier can demulsify crude oil emulsion and has high demulsification efficiency, low usage amount, low demulsification temperature, high salt resistance and other advantages. BRIEF DESCRIPTION OF DRAWINGS

[0039] FIG. 1 is an infrared absorption spectrum of the ion liquid of Example 1. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions and advantages of the application clearer, the technical solutions in the embodiments of the application will be described clearly and completely below in combination with the embodiments of the application. Obviously, the described embodiments are some embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0041] The application provides an ion liquid, which comprises a structural formula of Formula 1:

[0042] wherein R1 and R2 are each independently selected from C8-C18 alkyl, and n is an integer in 0-3.

[0043] The ionic liquid of the present application comprises a structural formula of Formula 1, wherein R1, R2 are each independently selected from C8-C18 alkyl, and n is an integer in 0-3. The C8-C18 alkyl of the present application refers to alkyl with carbon number of 8-18. When a substituent is specified as a group with a specific carbon number, all geometric isomers with the carbon number are included. The n of the present application is an integer in 0-3, i.e. n is 0, 1, 2 or 3. For example, R1, R2 can each independently be selected from -(CH2)7CH3, -CH(CH3)(CH2)5CH3, -CH2CH(CH3)(CH2)4CH3, -CH2C(CH3)2(CH2)3CH3, -(CH2)8CH3, -(CH2)9CH3, -(CH2) 10 -(CH2) 11 CH3, -(CH2)

[0044] According to the above scheme provided by the present application, the ionic liquid as a demulsifier is applied in crude oil emulsion demulsification, has the advantages of high demulsification efficiency, low use amount, low demulsification temperature, etc., and excellent demulsification effect under high salt conditions. The applicant analyzes the principle and considers that the reason may be that the ionic liquid has a specific functional group, has multiple hydrophobic chains, and can exhibit amphiphilicity and high interfacial activity. When applied in crude oil emulsion demulsification, the ionic liquid can quickly adsorb to the oil-water interface, replace the interfacial active substances on the interfacial film, greatly reduce the interfacial tension, soften or destroy the interfacial film, thereby reducing the stability of the interfacial film, promoting the occurrence of the demulsification process, and thus enabling the ionic liquid to demulsify efficiently at a low use amount and to demulsify efficiently under high salt conditions.

[0045] Specifically, the structural formula of the ionic liquid can be obtained by infrared absorption spectrum test.

[0046] In a specific embodiment, the ionic liquid is prepared by the following steps:

[0047] The alkylphenol, formaldehyde and polyamine are subjected to a first reaction to obtain a first product with a structural formula of Formula 2, the long-chain alkyl dimethyl tertiary amine is subjected to a second reaction with epichlorohydrin to obtain a second product with a structural formula of Formula 3, and then the first product and the second product are subjected to a third reaction to obtain the ionic liquid.

[0048] Specifically, the alkylphenol, formaldehyde and polyamine are subjected to a first reaction to obtain a first product, the first product has a structural formula of Formula 2, the long-chain alkyl dimethyl tertiary amine is subjected to a second reaction with epichlorohydrin to obtain a second product, the second product has a structural formula of Formula 3, and finally the first product and the second product are subjected to a third reaction to obtain the ionic liquid.

[0049] The application does not limit the specific selection of the alkyl phenol, the polyamine, and the long-chain alkyl dimethyl tertiary amine, which can be selected according to actual needs.

[0050] The application does not limit the specific parameter selection of the first reaction, which can be selected according to actual needs.

[0051] The application does not limit the specific selection of the alkyl phenol, the formaldehyde, and the polyamine, which can be selected according to actual needs.

[0052] The application does not limit the specific parameter selection of the second reaction, which can be selected according to actual needs.

[0053] The application does not limit the specific selection of the long-chain alkyl dimethyl tertiary amine and the epichlorohydrin, which can be selected according to actual needs.

[0054] The application does not limit the specific parameter selection of the third reaction, which can be selected according to actual needs.

[0055] The application does not limit the specific selection of the first product and the second product, which can be selected according to actual needs.

[0056] The application does not limit the specific selection of the first product and the second product, which can be selected according to actual needs.

[0057] The application does not limit the specific sequence of the first reaction and the second reaction, which can be selected according to actual needs.

[0058] The application, through the above preparation method, first grafts the alkyl phenol, the formaldehyde, and the polyamine to prepare a first product with a structure of formula 2, then ionizes the long-chain alkyl dimethyl tertiary amine and the epichlorohydrin to prepare a second product with a structure of formula 3, and finally opens the ring of the first product and the second product to obtain an ionic liquid with a structure of formula 1. Through the preparation method, the ionic liquid can have multiple hydrophobic chains, so that the ionic liquid exhibits amphiphilicity and high interfacial activity, and thus has high demulsification efficiency, low use amount, low demulsification temperature, and high salt resistance.

[0059] The application also provides a preparation method of an ionic liquid, including the following steps:

[0060] 1) performing a first reaction on an alkyl phenol, a formaldehyde, and a polyamine to obtain a first product with a structure of formula 2:

[0061] 2) performing a second reaction on a long-chain alkyl dimethyl tertiary amine and an epichlorohydrin to obtain a second product with a structure of formula 3:

[0062] 3) performing a third reaction on the first product and the second product to obtain an ionic liquid.

[0063] Specifically, step 1) is a first reaction of the alkyl phenol, the formaldehyde and the polyamine to obtain a first product having a structure of formula 2.

[0064] The application does not limit the specific selection of the alkyl phenol, which can be selected according to actual needs.

[0065] The application does not limit the specific selection of the polyamine, which can be selected according to actual needs.

[0066] The application does not limit the specific parameters of the first reaction, which can be selected according to actual needs.

[0067] The application does not limit the specific proportion of the alkyl phenol, the formaldehyde and the polyamine, which can be selected according to actual needs.

[0068] Step 2) is a second reaction of the long-chain alkyl dimethyl tertiary amine and the epichlorohydrin to obtain a second product having a structure of formula 3.

[0069] The application does not limit the specific selection of the long-chain alkyl dimethyl tertiary amine, which can be selected according to actual needs.

[0070] The application does not limit the specific parameters of the second reaction, which can be selected according to actual needs.

[0071] The application does not limit the specific proportion of the long-chain alkyl dimethyl tertiary amine and the epichlorohydrin, which can be selected according to actual needs.

[0072] Step 3) is a third reaction of the first product and the second product to obtain the ionic liquid.

[0073] The application does not limit the specific parameters of the third reaction, which can be selected according to actual needs.

[0074] The application does not limit the specific proportion of the first product and the second product, which can be selected according to actual needs.

[0075] The application does not limit the order of the first reaction and the second reaction, which can be selected according to actual needs.

[0076] The example liquid preparation method of the application can prepare an example liquid having a structure of formula 1, the ionic liquid has multiple hydrophobic chains, is applied to crude oil emulsion demulsification, has high demulsification efficiency, low use amount, low demulsification temperature and high salt resistance. And the synthesis process of the preparation method is simple, the preparation conditions are low and easy to operate, which is beneficial to the industrialized production of the ionic liquid.

[0077] In one specific embodiment, step 1) comprises the following steps:

[0078] After the alkyl phenol and the polyamine are mixed uniformly, the formaldehyde is added dropwise, and then the first reaction is carried out after 0.5-2h, and a first product is obtained;

[0079] The reaction temperature of the first reaction is 80-120℃, and the reaction time is 5-16h.

[0080] Specifically, first, the alkyl phenol and the polyamine are mixed, and after being mixed uniformly, the formaldehyde is added dropwise. After the dropwise addition is completed, the first reaction is carried out after 0.5-2h, and the reaction temperature of the first reaction is 80-120℃, for example, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃ or 120℃, etc., and the reaction time is 5-16h, for example, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h or 16h, etc. After the reaction is completed, the impurities and the solvent are removed, and the first product is obtained.

[0081] The application does not limit the specific parameters of the mixing treatment of the alkyl phenol and the polyamine, which can be selected according to actual needs.

[0082] The application does not limit the dropwise addition speed of the formaldehyde, which can be selected according to actual needs.

[0083] The application does not limit the specific selection of the solvent, which can be selected according to actual needs.

[0084] The application does not limit the specific process of removing the impurities and the solvent, which can be selected according to actual needs.

[0085] The application can effectively carry out the grafting reaction of the alkyl phenol, the formaldehyde and the polyamine through the preparation method, so as to realize the accurate preparation of the target first product, and the preparation process of the preparation method is simple, the equipment requirement is low, and the operation is easy.

[0086] In one specific embodiment, step 2) comprises the following steps:

[0087] The long-chain alkyl dimethyl tertiary amine is dissolved in a solvent, and then the epichlorohydrin is added dropwise, and the second reaction is carried out, and a second product is obtained;

[0088] The reaction temperature of the second reaction is 25-40℃, and the reaction time is 5-16h.

[0089] Specifically, the long-chain alkyl dimethyl tertiary amine is first dissolved in a solvent, and then epichlorohydrin is added dropwise into the solution. After the addition is completed, a second reaction is performed. The reaction temperature of the second reaction is 25-40°C, such as 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, or 40°C, etc. The reaction time is 5-16h, such as 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, or 16h, etc. After the reaction is completed, impurities and solvents are removed to obtain the second product.

[0090] The application does not limit the specific operation of dissolving the long-chain alkyl dimethyl tertiary amine in the solvent, which can be selected according to actual needs.

[0091] The application does not limit the specific selection of the solvent, which can be selected according to actual needs.

[0092] The application does not limit the dropping speed of epichlorohydrin, which can be selected according to actual needs.

[0093] The application does not limit the specific process of removing impurities and solvents, which can be selected according to actual needs.

[0094] The application can make the long-chain alkyl dimethyl tertiary amine and epichlorohydrin undergo ionization reaction through the preparation method, so that the second product can be obtained. The preparation method has low reaction temperature, low preparation condition requirement, and few types of raw materials, which are easy to obtain.

[0095] In one specific embodiment, step 3) includes the following steps:

[0096] The first product and the second product are dissolved in a solvent, and then a third reaction is performed to obtain an ionic liquid.

[0097] The reaction temperature of the third reaction is 60-120°C, and the reaction time is 5-16h.

[0098] Specifically, the first product and the second product are uniformly mixed in a solvent, so that the first product and the second product are both dissolved in the solvent, and then a third reaction is performed. The reaction temperature of the third reaction is 60-120°C, such as 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, or 120°C, etc. The reaction time is 5-16h, such as 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, or 16h, etc. After the reaction is completed, the solvent is removed to obtain the ionic liquid.

[0099] The present application does not limit the specific mixing parameters of the first product and the second product in the solvent, which can be selected according to actual needs.

[0100] The present application is not limited to the reaction order of the first reaction and the second reaction, which can be selected according to actual needs.

[0101] The present application can make the first product and the second product perform efficient ring-opening reaction through the above-mentioned method, and realize the successful preparation of ionic liquid. In addition, the preparation process of the preparation method is simple, the equipment requirement is low, the energy is saved, and it is conducive to large-scale production of ionic liquid.

[0102] In a specific embodiment, the molar ratio of the alkylphenol, formaldehyde and polyamine is 1:(1.5-2.5):(1.5-2.5), for example, 1:1.5:1.5, 1:1.5:2, 1:1.5:2.5, 1:2:1.5, 1:2:2, 1:2:2.5, 1:2.5:1.5, 1:2.5:2 or 1:2.5:2.5, etc. When the molar ratio of the alkylphenol, formaldehyde and polyamine is within the above range, the alkylphenol, formaldehyde and polyamine can perform sufficient grafting reaction, avoiding waste of raw materials, so as to prepare the first product with higher purity, providing a basis for subsequent preparation of ionic liquid.

[0103] In a specific embodiment, the molar ratio of the long-chain alkyl dimethyl tertiary amine and the epichlorohydrin is 1:1. The long-chain alkyl dimethyl tertiary amine and the epichlorohydrin can perform sufficient complexation reaction, so as to prepare the second product with higher purity, avoiding waste of raw materials and complication of impurity removal step caused by excess long-chain alkyl dimethyl tertiary amine or epichlorohydrin.

[0104] In a specific embodiment, the molar ratio of the first product and the second product is 1:2. The first product and the second product can perform sufficient ring-opening reaction, which can reduce the occurrence of side reactions and realize the preparation of target ionic liquid.

[0105] In a specific embodiment, the alkylphenol includes one or more of 4-octylphenol, 4-dodecylphenol, 4-tetradecylphenol, 4-hexadecylphenol and 4-octadecylphenol, and the polyamine is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine. When the alkylphenol is selected from the above-mentioned compounds, the above-mentioned compounds have long-chain alkyl functional groups and hydroxyl groups, so as to provide long hydrophobic chains and hydrophilic chains for ionic liquid, laying a foundation for the preparation of ionic liquid with hydrophobic structure, which is conducive to the preparation of ionic liquid with amphiphilic property, so that the ionic liquid can exhibit excellent demulsification efficiency.

[0106] In an embodiment, the polyamine includes at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. When the polyamine is selected from the above compounds, the polyamine can be more fully grafted with the alkylphenol and the formaldehyde to obtain a first product having amphiphilicity, so that a subsequent ionic liquid having a specific functional group can be prepared, and the demulsification efficiency of the ionic liquid is improved.

[0107] In an embodiment, the long-chain alkyl dimethyl tertiary amine includes at least one of octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, and octadecyl dimethyl tertiary amine. When the long-chain alkyl dimethyl tertiary amine is selected from the above compounds, the long-chain alkyl dimethyl tertiary amine can be fully ionized with the epichlorohydrin to generate a second product having a long-chain alkyl group, which is conducive to the subsequent ionic liquid having a structural formula with multiple long-chain alkyl groups, so that the amphiphilicity of the ionic liquid is improved, and the demulsification efficiency of the ionic liquid is improved.

[0108] In an embodiment, the solvent includes at least one of methanol, ethanol, tetrahydrofuran, acetone, dioxane, toluene, and xylene. When the solvent is selected from the above compounds, the alkylphenol, the formaldehyde, the polyamine, and the long-chain alkyl dimethyl tertiary amine can be fully dissolved in the solvent with the epichlorohydrin, which is conducive to the first reaction, the second reaction, and the third reaction, and the components do not react with the solvent, so that the occurrence of a side reaction is avoided, and the successful preparation of the ionic liquid is ensured.

[0109] The present application provides a demulsifier including the above-mentioned ionic liquid. The demulsifier has high demulsification efficiency in the demulsification of crude oil emulsion, and has high demulsification efficiency in the case of low use amount, low demulsification temperature, or high environmental salinity.

[0110] The present application provides a method for demulsifying crude oil emulsion, including the following steps: using the above-mentioned demulsifier to demulsify the crude oil emulsion. The demulsification process of the demulsification method is simple, and the use amount of the demulsifier, the energy cost, and the time cost are low, which lays a foundation for the large-scale application of the demulsifier in the crude oil emulsion.

[0111] Hereinafter, the present application will be further described in detail through specific embodiments.

[0112] Embodiment 1

[0113] The preparation process of the ionic liquid provided in this embodiment includes the following steps:

[0114] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylene triamine were mixed uniformly at 50°C, then 0.21 mol of formaldehyde was added dropwise and incubated for 2 h, then 50 mL of dimethylbenzene was added, warmed to 100°C for 12 h, and the solvent and impurities were removed to obtain a first product;

[0115] wherein the molar ratio of 4-dodecylphenol, formaldehyde, and diethylene triamine is 1:2.1:2.1;

[0116] 2. 0.2 mol of dodecyl dimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, and after the addition was completed, it was reacted at 30°C for 10 h, and the solvent and impurities were removed to obtain a second product;

[0117] wherein the molar ratio of dodecyl dimethyl tertiary amine and epichlorohydrin is 1:1;

[0118] 3. 0.1 mol of the first product and 0.2 mol of the second product were added to 100 mL of dimethylbenzene, mixed uniformly, then warmed to 100°C for 10 h, and after the solvent was removed, an ionic liquid was obtained:

[0119] wherein the molar ratio of the first product and the second product is 1:2.

[0120] Example 2

[0121] The preparation process of the ionic liquid provided in this example includes the following steps:

[0122] 1. 0.1 mol of 4-tetradecylphenol and 0.21 mol of triethylene tetramine were mixed uniformly at 50°C, then 0.21 mol of formaldehyde was added dropwise and incubated for 2 h, then 50 mL of dimethylbenzene was added, warmed to 100°C for 12 h, and the solvent and impurities were removed to obtain a first product;

[0123] wherein the molar ratio of 4-tetradecylphenol, formaldehyde, and triethylene tetramine is 1:2.1:2.1;

[0124] 2. 0.2 mol of tetradecyl dimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, and after the addition was completed, it was reacted at 30°C for 10 h, and the solvent and impurities were removed to obtain a second product;

[0125] wherein the molar ratio of dodecyl dimethyl tertiary amine and epichlorohydrin is 1:2;

[0126] 3. 0.1 mol of the first product and 0.2 mol of the second product were added to 100 mL of dimethylbenzene, mixed uniformly, then warmed to 100°C for 10 h, and after the solvent was removed, an ionic liquid was obtained:

[0127] wherein the molar ratio of the first product and the second product is 1:2.

[0128] Example 3

[0129] The preparation process of the ionic liquid provided in this example includes the following steps:

[0130] 1. 0.1 mol of 4-hexadecylphenol and 0.21 mol of tetraethylenepentamine were uniformly mixed at 50°C, then 0.21 mol of formaldehyde was added dropwise and incubated for 2 h, 50 mL of dimethylbenzene was then added, the temperature was raised to 100°C, and the reaction was carried out for 12 h, after which the solvent and impurities were removed to obtain a first product;

[0131] wherein the molar ratio of 4-hexadecylphenol, formaldehyde, and tetraethylenepentamine is 1:2.1:2.1;

[0132] 2. 0.2 mol of hexadecyldimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, after the dropwise addition was completed, the reaction was carried out at 30°C for 10 h, and then the solvent and impurities were removed to obtain a second product;

[0133] wherein the molar ratio of hexadecyldimethyl tertiary amine and epichlorohydrin is 1:1;

[0134] 3. 0.1 mol of the first product and 0.2 mol of the second product were added to 100 mL of dimethylbenzene, uniformly mixed, and then the temperature was raised to 100°C, and the reaction was carried out for 10 h, after which the solvent was removed to obtain an ionic liquid:

[0135] wherein the molar ratio of the first product and the second product is 1:2.

[0136] Example 4

[0137] The preparation process of the ionic liquid provided in this example includes the following steps:

[0138] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylenetriamine were uniformly mixed at 50°C, then 0.21 mol of formaldehyde was added dropwise and incubated for 2 h, 50 mL of dimethylbenzene was then added, the temperature was raised to 80°C, and the reaction was carried out for 16 h, after which the solvent and impurities were removed to obtain a first product;

[0139] wherein the molar ratio of 4-dodecylphenol, formaldehyde, and diethylenetriamine is 1:2.1:2.1;

[0140] 2. 0.2 mol of dodecyldimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, after the dropwise addition was completed, the reaction was carried out at 30°C for 10 h, and then the solvent and impurities were removed to obtain a second product;

[0141] wherein the molar ratio of the dodecyl dimethyl tertiary amine to the epichlorohydrin is 1:1.

[0142] 3. 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of xylene, mixed uniformly, and then heated to 100°C for 10 h, and after removing the solvent, an ionic liquid is obtained:

[0143] wherein the molar ratio of the first product to the second product is 1:2.

[0144] Example 5

[0145] The preparation process of the ionic liquid provided in this example includes the following steps:

[0146] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylenetriamine are mixed uniformly at 50°C, then 0.21 mol of formaldehyde is added dropwise and incubated for 2 h, and then 50 mL of xylene is added, heated to 120°C for 5 h, and after removing the solvent and impurities, a first product is obtained;

[0147] wherein the molar ratio of the 4-dodecylphenol, formaldehyde, and diethylenetriamine is 1:2.1:2.1.

[0148] 2. 0.2 mol of dodecyl dimethyl tertiary amine is dissolved in 50 mL of methanol, and then 0.2 mol of epichlorohydrin is added dropwise, and after the dropwise addition is completed, it is reacted at 30°C for 10 h, and after removing the solvent and impurities, a second product is obtained;

[0149] wherein the molar ratio of the dodecyl dimethyl tertiary amine to the epichlorohydrin is 1:1.

[0150] 3. 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of xylene, mixed uniformly, and then heated to 100°C for 10 h, and after removing the solvent, an ionic liquid is obtained:

[0151] wherein the molar ratio of the first product to the second product is 1:2.

[0152] Example 6

[0153] The preparation process of the ionic liquid provided in this example includes the following steps:

[0154] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylenetriamine are mixed uniformly at 50°C, then 0.21 mol of formaldehyde is added dropwise and incubated for 2 h, and then 50 mL of xylene is added, heated to 130°C for 4 h, and after removing the solvent and impurities, a first product is obtained;

[0155] wherein the molar ratio of 4-dodecylphenol, formaldehyde, diethylenetriamine is 1:2.1:2.1;

[0156] 2. Dissolve 0.2 mol of dodecyldimethyl tertiary amine in 50 mL of methanol, then add 0.2 mol of epichlorohydrin dropwise, and after the dropwise addition is complete, react at 30°C for 10 h, and remove the solvent and impurities to obtain a second product;

[0157] wherein the molar ratio of dodecyldimethyl tertiary amine to epichlorohydrin is 1:1;

[0158] 3. Add 0.1 mol of the first product and 0.2 mol of the second product to 100 mL of xylene, mix uniformly, then warm to 100°C and react for 10 h, and after the solvent is removed, an ionic liquid is obtained:

[0159] wherein the molar ratio of the first product to the second product is 1:2.

[0160] Example 7

[0161] The preparation process of the ionic liquid provided in this example includes the following steps:

[0162] 1. Mix 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylenetriamine uniformly at 50°C, then add 0.21 mol of formaldehyde and incubate for 2 h, then add 50 mL of xylene, warm to 100°C and react for 12 h, and after the solvent and impurities are removed, a first product is obtained;

[0163] wherein the molar ratio of 4-dodecylphenol, formaldehyde, diethylenetriamine is 1:2.1:2.1;

[0164] 2. Dissolve 0.2 mol of dodecyldimethyl tertiary amine in 50 mL of methanol, then add 0.2 mol of epichlorohydrin dropwise, and after the dropwise addition is complete, react at 25°C for 16 h, and remove the solvent and impurities to obtain a second product;

[0165] wherein the molar ratio of dodecyldimethyl tertiary amine to epichlorohydrin is 1:1;

[0166] 3. Add 0.1 mol of the first product and 0.2 mol of the second product to 100 mL of xylene, mix uniformly, then warm to 100°C and react for 10 h, and after the solvent is removed, an ionic liquid is obtained:

[0167] wherein the molar ratio of the first product to the second product is 1:2.

[0168] Example 8

[0169] The preparation process of the ionic liquid provided in the embodiment comprises the following steps:

[0170] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylene triamine are uniformly mixed at 50°C, then 0.21 mol of formaldehyde is added dropwise and incubated for 2 h, 50 mL of dimethylbenzene is then added, the temperature is raised to 100°C, and reaction is performed for 12 h, after which the solvent and impurities are removed to obtain a first product;

[0171] The molar ratio of 4-dodecylphenol, formaldehyde and diethylene triamine is 1:2.1:2.1.

[0172] 2. 0.2 mol of dodecyl dimethyl tertiary amine is dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin is added dropwise, after the dropwise addition is completed, reaction is performed at 40°C for 5 h, and the solvent and impurities are removed to obtain a second product;

[0173] The molar ratio of dodecyl dimethyl tertiary amine and epichlorohydrin is 1:1.

[0174] 3. 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of dimethylbenzene, the mixture is uniformly mixed, the temperature is raised to 100°C, and reaction is performed for 10 h, after which the solvent is removed to obtain an ionic liquid:

[0175] The molar ratio of the first product and the second product is 1:2.

[0176] Embodiment 9

[0177] The preparation process of the ionic liquid provided in the embodiment comprises the following steps:

[0178] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylene triamine are uniformly mixed at 50°C, then 0.21 mol of formaldehyde is added dropwise and incubated for 2 h, 50 mL of dimethylbenzene is then added, the temperature is raised to 100°C, and reaction is performed for 12 h, after which the solvent and impurities are removed to obtain a first product;

[0179] The molar ratio of 4-dodecylphenol, formaldehyde and diethylene triamine is 1:2.1:2.1.

[0180] 2. 0.2 mol of dodecyl dimethyl tertiary amine is dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin is added dropwise, after the dropwise addition is completed, reaction is performed at 50°C for 4 h, and the solvent and impurities are removed to obtain a second product;

[0181] The molar ratio of dodecyl dimethyl tertiary amine and epichlorohydrin is 1:1.

[0182] 3. 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of dimethylbenzene, mixed uniformly, and then heated to 100°C for 10 h. After removing the solvent, an ionic liquid is obtained:

[0183] The molar ratio of the first product to the second product is 1:2.

[0184] Example 10

[0185] The preparation process of the ionic liquid provided in this example includes the following steps:

[0186] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylenetriamine are mixed uniformly at 50°C. Then, 0.21 mol of formaldehyde is added dropwise and incubated for 2 h. Subsequently, 50 mL of dimethylbenzene is added, heated to 100°C for 12 h, and then the solvent and impurities are removed to obtain a first product;

[0187] The molar ratio of 4-dodecylphenol, formaldehyde, and diethylenetriamine is 1:2.1:2.1.

[0188] 2. 0.2 mol of dodecyl dimethyl tertiary amine is dissolved in 50 mL of methanol, and then 0.2 mol of epichlorohydrin is added dropwise. After the addition is completed, it is reacted at 30°C for 10 h. The solvent and impurities are removed to obtain a second product;

[0189] The molar ratio of dodecyl dimethyl tertiary amine to epichlorohydrin is 1:1.

[0190] 3. 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of dimethylbenzene, mixed uniformly, and then heated to 60°C for 16 h. After removing the solvent, an ionic liquid is obtained:

[0191] The molar ratio of the first product to the second product is 1:2.

[0192] Example 11

[0193] The preparation process of the ionic liquid provided in this example includes the following steps:

[0194] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylenetriamine are mixed uniformly at 50°C. Then, 0.21 mol of formaldehyde is added dropwise and incubated for 2 h. Subsequently, 50 mL of dimethylbenzene is added, heated to 100°C for 12 h, and then the solvent and impurities are removed to obtain a first product;

[0195] The molar ratio of 4-dodecylphenol, formaldehyde, and diethylenetriamine is 1:2.1:2.1.

[0196] 2, 0.2 mol of dodecyl dimethyl tertiary amine is dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin is added dropwise, after the addition is completed, it is reacted at 30°C for 10 h, and the solvent and impurities are removed to obtain a second product;

[0197] The molar ratio of dodecyl dimethyl tertiary amine to epichlorohydrin is 1:1.

[0198] 3, 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of xylene, and after being uniformly mixed, it is heated to 120°C and reacted for 5 h, and after the solvent is removed, an ionic liquid is obtained:

[0199] The molar ratio of the first product to the second product is 1:2.

[0200] Example 12

[0201] The preparation process of the ionic liquid provided in this embodiment includes the following steps:

[0202] 1, 0.1 mol of 4-dodecyl phenol and 0.21 mol of diethylene triamine are uniformly mixed at 50°C, then 0.21 mol of formaldehyde is added dropwise and incubated for 2 h, then 50 mL of xylene is added, heated to 100°C and reacted for 12 h, and after the solvent and impurities are removed, a first product is obtained;

[0203] The molar ratio of 4-dodecyl phenol, formaldehyde, and diethylene triamine is 1:2.1:2.1.

[0204] 2, 0.2 mol of dodecyl dimethyl tertiary amine is dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin is added dropwise, after the addition is completed, it is reacted at 30°C for 10 h, and the solvent and impurities are removed to obtain a second product;

[0205] The molar ratio of dodecyl dimethyl tertiary amine to epichlorohydrin is 1:1.

[0206] 3, 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of xylene, and after being uniformly mixed, it is heated to 130°C and reacted for 4 h, and after the solvent is removed, an ionic liquid is obtained:

[0207] The molar ratio of the first product to the second product is 1:2.

[0208] Example 13

[0209] The preparation process of the ionic liquid provided in this embodiment includes the following steps:

[0210] 1. 0.1 mol of 4-dodecylphenol and 0.15 mol of diethylene triamine were mixed uniformly at 50°C, then 0.15 mol of formaldehyde was added dropwise and incubated for 2 h, then 50 mL of dimethylbenzene was added, and the temperature was raised to 100°C for 12 h of reaction, and the solvent and impurities were removed to obtain a first product;

[0211] wherein the molar ratio of 4-dodecylphenol, formaldehyde, and diethylene triamine is 1:1.5:1.5;

[0212] 2. 0.2 mol of dodecyl dimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, and after the addition was completed, it was reacted at 30°C for 10 h, and the solvent and impurities were removed to obtain a second product;

[0213] wherein the molar ratio of dodecyl dimethyl tertiary amine and epichlorohydrin is 1:1;

[0214] 3. 0.1 mol of the first product and 0.2 mol of the second product were added to 100 mL of dimethylbenzene, mixed uniformly, and then the temperature was raised to 100°C for 10 h of reaction, and after the solvent was removed, an ionic liquid was obtained:

[0215] wherein the molar ratio of the first product and the second product is 1:2.

[0216] Example 14

[0217] The preparation process of the ionic liquid provided by the embodiment includes the following steps:

[0218] 1. 0.1 mol of 4-dodecylphenol and 0.15 mol of diethylene triamine were mixed uniformly at 50°C, then 0.15 mol of formaldehyde was added dropwise and incubated for 2 h, then 50 mL of dimethylbenzene was added, and the temperature was raised to 100°C for 12 h of reaction, and the solvent and impurities were removed to obtain a first product;

[0219] wherein the molar ratio of 4-dodecylphenol, formaldehyde, and diethylene triamine is 1:2.5:2.5;

[0220] 2. 0.2 mol of dodecyl dimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, and after the addition was completed, it was reacted at 30°C for 10 h, and the solvent and impurities were removed to obtain a second product;

[0221] wherein the molar ratio of dodecyl dimethyl tertiary amine and epichlorohydrin is 1:1;

[0222] 3. 0.1 mol of the first product and 0.2 mol of the second product were added to 100 mL of dimethylbenzene, mixed uniformly, and then the temperature was raised to 100°C for 10 h of reaction, and after the solvent was removed, an ionic liquid was obtained:

[0223] wherein the molar ratio of the first product and the second product is 1:2.

[0224] Example 15

[0225] The preparation process of the ionic liquid provided in this example includes the following steps:

[0226] 1. 0.1 mol of 4-dodecylphenol and 0.15 mol of diethylenetriamine were uniformly mixed at 50°C, then 0.15 mol of formaldehyde was added dropwise and incubated for 2 h, 50 mL of dimethylbenzene was then added, the temperature was raised to 100°C and reacted for 12 h, and then the solvent and impurities were removed to obtain a first product;

[0227] wherein the molar ratio of 4-dodecylphenol, formaldehyde, and diethylenetriamine is 1:1.4:1.4;

[0228] 2. 0.2 mol of dodecyl dimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, and after the addition was completed, it was reacted at 30°C for 10 h, and then the solvent and impurities were removed to obtain a second product;

[0229] wherein the molar ratio of dodecyl dimethyl tertiary amine and epichlorohydrin is 1:1;

[0230] 3. 0.1 mol of the first product and 0.2 mol of the second product were added to 100 mL of dimethylbenzene, uniformly mixed, then the temperature was raised to 100°C and reacted for 10 h, and then the solvent was removed to obtain an ionic liquid:

[0231] wherein the molar ratio of the first product and the second product is 1:2.

[0232] Example 16

[0233] The preparation process of the ionic liquid provided in this example includes the following steps:

[0234] 1. 0.1 mol of 4-dodecylphenol and 0.15 mol of diethylenetriamine were uniformly mixed at 50°C, then 0.15 mol of formaldehyde was added dropwise and incubated for 2 h, 50 mL of dimethylbenzene was then added, the temperature was raised to 100°C and reacted for 12 h, and then the solvent and impurities were removed to obtain a first product;

[0235] wherein the molar ratio of 4-dodecylphenol, formaldehyde, and diethylenetriamine is 1:1.4:1.4;

[0236] 2, 0.2 mol of dodecyl dimethyl tertiary amine is dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin is added dropwise, after the addition is completed, it is reacted at 30°C for 10h, the solvent and impurities are removed to obtain a second product;

[0237] The molar ratio of dodecyl dimethyl tertiary amine to epichlorohydrin is 1:1.

[0238] 3, 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of dimethylbenzene, after being uniformly mixed, it is heated to 100°C and reacted for 10h, after the solvent is removed, an ionic liquid is obtained:

[0239] The molar ratio of the first product to the second product is 1:2.

[0240] Example 17

[0241] The preparation process of the ionic liquid provided in this embodiment includes the following steps:

[0242] 1, 0.1 mol of 4-octadecylphenol and 0.21 mol of diethylenetriamine are uniformly mixed at 50°C, then 0.21 mol of formaldehyde is added dropwise and incubated for 2h, then 50 mL of dimethylbenzene is added, heated to 100°C and reacted for 12h, after the solvent and impurities are removed, a first product is obtained;

[0243] The molar ratio of 4-octadecylphenol, formaldehyde and diethylenetriamine is 1:2.1:2.1.

[0244] 2, 0.2 mol of dodecyl dimethyl tertiary amine is dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin is added dropwise, after the addition is completed, it is reacted at 30°C for 10h, the solvent and impurities are removed to obtain a second product;

[0245] The molar ratio of dodecyl dimethyl tertiary amine to epichlorohydrin is 1:1.

[0246] 3, 0.1 mol of the first product and 0.2 mol of the second product are added to 100 mL of dimethylbenzene, after being uniformly mixed, it is heated to 100°C and reacted for 10h, after the solvent is removed, an ionic liquid is obtained:

[0247] The molar ratio of the first product to the second product is 1:2.

[0248] Example 18

[0249] The preparation process of the ionic liquid provided in this embodiment includes the following steps:

[0250] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylenetriamine were mixed uniformly at 50°C, then 0.21 mol of formaldehyde was added dropwise and incubated for 2 h, then 50 mL of xylene was added, and the temperature was raised to 100°C for 12 h of reaction, and the solvent and impurities were removed to obtain a first product;

[0251] wherein the molar ratio of 4-dodecylphenol, formaldehyde, and diethylenetriamine is 1:2.1:2.1;

[0252] 2. 0.2 mol of octadecyldimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, and after the addition was completed, it was reacted at 30°C for 10 h, and the solvent and impurities were removed to obtain a second product;

[0253] wherein the molar ratio of octadecyldimethyl tertiary amine and epichlorohydrin is 1:1;

[0254] 3. 0.1 mol of the first product and 0.2 mol of the second product were added to 100 mL of xylene, mixed uniformly, and then the temperature was raised to 100°C for 10 h of reaction, and after the solvent was removed, an ionic liquid was obtained:

[0255] wherein the molar ratio of the first product and the second product is 1:2.

[0256] Example 19

[0257] 1. 0.1 mol of 4-dodecylphenol and 0.21 mol of diethylenetriamine were mixed uniformly at 50°C, then 0.21 mol of formaldehyde was added dropwise and incubated for 2 h, then 50 mL of toluene was added, and the temperature was raised to 100°C for 12 h of reaction, and the solvent and impurities were removed to obtain a first product;

[0258] wherein the molar ratio of 4-dodecylphenol, formaldehyde, and diethylenetriamine is 1:2.1:2.1;

[0259] 2. 0.2 mol of dodecyl dimethyl tertiary amine was dissolved in 50 mL of methanol, then 0.2 mol of epichlorohydrin was added dropwise, and after the addition was completed, it was reacted at 30°C for 10 h, and the solvent and impurities were removed to obtain a second product;

[0260] wherein the molar ratio of dodecyl dimethyl tertiary amine and epichlorohydrin is 1:1;

[0261] 3. 0.1 mol of the first product and 0.2 mol of the second product were added to 100 mL of toluene, mixed uniformly, and then the temperature was raised to 100°C for 10 h of reaction, and after the solvent was removed, an ionic liquid was obtained:

[0262] wherein the molar ratio of the first product and the second product is 1:2.

[0263] Comparative Example 1

[0264] The preparation process of the ionic liquid provided by the present comparative example comprises the following steps:

[0265] 1. 0.1 mol of 4-hexadecylphenol and 0.21 mol of tetraethylenepentamine were mixed uniformly at 50°C, then 0.21 mol of formaldehyde was added dropwise and incubated for 2 h, then 50 mL of dimethylbenzene was added, the temperature was raised to 100°C and reacted for 12 h, and then the solvent and impurities were removed to obtain the ionic liquid:

[0266] The molar ratio of 4-hexadecylphenol, formaldehyde and tetraethylenepentamine is 1:2.1:2.1.

[0267] Comparative Example 2

[0268] The present comparative example uses a commercial demulsifier SA-002 purchased from Nantong Shina Water Treatment Reagent Co., Ltd.

[0269] Test Example 1

[0270] The infrared absorption spectrum test of the ionic liquid of Example 1 is shown in Figure 1. As shown in Figure 1, the absorption peak at 3500-3407 cm -1 is the stretching vibration peak of the tertiary alcohol O-H and N-H groups (part of the spectrum peak overlaps), the absorption peaks at 2925 cm -1 , 2850 cm -1 , 1463 cm -1 are characteristic peaks of -CH2 groups, the absorption peak at 755 cm -1 belongs to the characteristic peak of long-chain -(CH2) n , wherein n>4, the absorption peak at 1600 cm -1 is the stretching vibration of the aromatic ring C=C group, and the absorption peak at 1203 cm -1 is the stretching vibration absorption peak of Ar-OH, which indicates that the hydrophobic long chain is successfully connected to the hydrophilic long chain, and the ionic liquid of Example 1 is successfully synthesized.

[0271] Test Example 2

[0272] 150 parts by weight of crude oil was added to 350 parts by weight of water, heated to 60°C, and stirred at a speed of 11000 r / min for 20 minutes to obtain a stable crude oil emulsion.

[0273] The ionic liquid demulsifier in the examples and comparative examples was dissolved in a mixed solution of xylene and ethanol with a volume ratio of 75:25 to obtain a 0.4% mass fraction demulsifier solution; then 1 volume part of the demulsifier solution was added to 20 volume parts of crude oil emulsion and mixed uniformly by oscillation, and the dehydration rate was measured for 2 h in a 55°C water bath to characterize the demulsification efficiency. The results are shown in Table 1.

[0274] Table 1

[0275] Test Example 3

[0276] The ionic liquid in Example 1 was dissolved in a mixed solution of xylene and ethanol with a volume ratio of 75:25 to obtain demulsifier solutions with mass fractions of 0.5%, 0.4%, 0.3% and 0.2% respectively; then 1 volume part of the demulsifier solution with different mass fractions was added to 20 volume parts of crude oil emulsion and mixed uniformly by oscillation, and the dehydration rate was measured for 2 h in a 55°C water bath to characterize the demulsification efficiency. The concentration of 200 mg / L was used as Comparative Example 2. The results are shown in Table 2.

[0277] Table 2

[0278] Test Example 4

[0279] The ionic liquid in Example 1 was dissolved in a mixed solution of xylene and ethanol with a volume ratio of 75:25 to obtain a 0.4% mass fraction demulsifier solution; the demulsifier solution was divided into 4 parts and mixed with 20 times volume of crude oil emulsion by oscillation, and then was placed in a water bath at 50°C, 55°C, 60°C and 65°C respectively, and the dehydration rate was measured to characterize the demulsification efficiency. The concentration of 200 mg / L was measured at 50°C and 55°C respectively. The results are shown in Table 3.

[0280] Table 3

[0281] Test Example 5

[0282] The ionic liquid in Example 1 was dissolved in a mixed solution of xylene and ethanol with a volume ratio of 75:25 to obtain a 0.4% mass fraction demulsifier solution; the demulsifier solution was divided into 6 parts and mixed with 20 times volume of crude oil emulsion with different salinity by oscillation, and then was placed in a 55°C water bath, and the dehydration rate was measured to characterize the demulsification efficiency. The commercial demulsifier SA-001 with a concentration of 200 mg / L was used as Comparative Example. The results are shown in Table 4.

[0283] Table 4

[0284] As can be seen from Table 1, according to the comparison of Examples 1-19 and Comparative Examples 1-2, the ionic liquid provided by the application can exhibit excellent demulsification performance as a demulsifier; as can be seen from Table 2, the ionic liquid provided by the application can achieve high demulsification efficiency when the concentration thereof in the crude oil emulsion is 100-250 mg / L as a demulsifier; as can be seen from Table 3, the ionic liquid provided by the application still exhibits high demulsification performance under low-temperature conditions of 50-60°C; as can be seen from Table 4, the ionic liquid provided by the application can achieve high demulsification efficiency and has high salt resistance under high-salt conditions. In summary, the ionic liquid provided by the application has the advantages of high demulsification efficiency, low use amount, low demulsification temperature and excellent demulsification effect under high-salt conditions when applied to the demulsification of crude oil emulsion as a demulsifier.

[0285] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, but not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. An ionic liquid, wherein, The ionic liquid comprises a structural formula of Formula 1: wherein R1, R2 are each independently selected from C8-C18 alkyl groups, and n is an integer from 0 to 3.

2. The ionic liquid of claim 1, wherein, The ionic liquid is prepared by the following steps: subjecting an alkyl phenol, formaldehyde and a polyamine to a first reaction to obtain a first product having the structural formula of Formula 2, subjecting a long chain alkyl dimethyl tertiary amine to a second reaction with epichlorohydrin to obtain a second product having the structural formula of Formula 3, and then subjecting the first product and the second product to a third reaction to obtain the ionic liquid:

3. A process for the preparation of an ionic liquid as claimed in claim 1 or 2, wherein, comprising the following steps: 1) subjecting an alkyl phenol, formaldehyde and a polyamine to a first reaction to obtain a first product having the structure of Formula 2: 2) subjecting the long chain alkyl dimethyl tertiary amine to a second reaction with epichlorohydrin to obtain a second product having the structure of Formula 3: 3) subjecting the first product and the second product to a third reaction to obtain the ionic liquid.

4. The method for preparing ionic liquid as described in claim 3, wherein, Step 1) comprises the following steps: After the alkylphenol is mixed uniformly with the polyamine, formaldehyde is added dropwise and reacted for 0.5-2h, and then a solvent is added to perform a first reaction to obtain the first product; wherein the reaction temperature of the first reaction is 80-120℃, and the reaction time is 5-16h.

5. The method of preparing an ionic liquid as claimed in claim 3 or 4, wherein, Step 2) comprises the following steps: The long-chain alkyl dimethyl tertiary amine is dissolved in a solvent, and then the epichlorohydrin is added dropwise to perform a second reaction to obtain the second product; wherein the reaction temperature of the second reaction is 25-40℃, and the reaction time is 5-16h.

6. The method of making an ionic liquid according to any one of claims 3-5, wherein, Step 3) comprises the following steps: The first product and the second product are dissolved in a solvent, and then the third reaction is performed to obtain the ionic liquid; wherein the reaction temperature of the third reaction is 60-120℃, and the reaction time is 5-16h.

7. The method of making an ionic liquid as claimed in any one of claims 3 to 6 wherein, The molar ratio of the alkylphenol, formaldehyde, and polyamine is 1:(1.5-2.5):(1.5-2.5); and / or, the molar ratio of the long-chain alkyl dimethyl tertiary amine and epichlorohydrin is 1:1; and / or, the molar ratio of the first product and the second product is 1:

2.

8. The method of making an ionic liquid as claimed in any one of claims 3 to 7 wherein, The alkylphenol comprises one or more of 4-octylphenol, 4-dodecylphenol, 4-tetradecylphenol, 4-hexadecylphenol, and 4-octadecylphenol; and / or, the polyamine comprises at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; and / or, the long-chain alkyl dimethyl tertiary amine comprises at least one of octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, and octadecyl dimethyl tertiary amine; and / or, the solvent comprises at least one of methanol, ethanol, tetrahydrofuran, acetone, dioxane, toluene, and xylene.

9. A demulsifier, wherein, The demulsifier comprises the ionic liquid of claim 1 or 2.

10. A method of breaking an emulsion of a crude oil, wherein, comprising the following steps: The crude oil emulsion is demulsified by the demulsifier of claim 9.

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