WO2018006495A1

WO2018006495A1 - Method for preparing carboxylate-type ionic liquid and use of carboxylate-type ionic liquid

Info

Publication number: WO2018006495A1
Application number: PCT/CN2016/098966
Authority: WO
Inventors: 孙大陟; 雍怀松
Original assignee: 南方科技大学
Priority date: 2016-07-08
Filing date: 2016-09-14
Publication date: 2018-01-11
Also published as: CN106187900A

Abstract

Provided are a method for preparing a carboxylate-type ionic liquid and a use of the carboxylate-type ionic liquid. The method comprises: in a protective atmosphere and a sealed environment, subjecting a carboxylic ester and a Lewis base to a chemical reaction so as to obtain the carboxylate-type ionic liquid, wherein the Lewis base is a tertiary amine-type or tertiary phosphorus-type Lewis base, and the temperature of the above-mentioned chemical reaction is between the boiling point temperatures of the carboxylic ester and the Lewis base.

Description

Method for preparing carboxylate type ionic liquid and use of carboxylate type ionic liquid

Technical field

The present invention relates to the field of materials technology, and in particular to a method for preparing a carboxylate type ionic liquid and a use of a carboxylate type ionic liquid.

Background technique

Generally, a salt having a melting point below 100 degrees Celsius is referred to as an ionic liquid. Ionic liquids generally consist of organic cations and weakly ionized anions, wherein typical organic cations which can form ionic liquids generally contain N, P or S. Ionic liquids have many important applications, such as for catalysts, plastic additives, dispersants, and lubricant additives.

Although ionic liquids can be used as additive materials, such as lubricating oil additives, to exhibit some excellent performance, there are still some technical problems to be overcome in future applications. The most typical three technical problems are as follows: First, the use of conventional inexpensive halide ionic liquids as additives can cause severe corrosion of some metal materials, such as corrosion of iron or steel; and second, traditional ionic liquid synthesis methods, such as The preparation method of the carboxylate type ionic liquid tends to be difficult to obtain the reaction raw material or the preparation process includes multiple steps, the process is lengthy, the energy consumption is high, and sometimes a large amount of waste is caused. Third, most of the existing ionic liquids are highly polar substances, and most of them are incompatible with non-polar media. These three technical problems limit the application of ionic liquids, especially their use in oily non-polar media.

Therefore, the current ionic liquid related technology still needs to be improved.

Summary of the invention

The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, it is an object of the present invention to provide a process which is simple, economical, easy to implement, or capable of rapidly and efficiently preparing a halide-free carboxylate-type ionic liquid.

In one aspect of the invention, the invention provides a method of preparing a carboxylate-type ionic liquid. According to an embodiment of the invention, the method comprises: chemically reacting a carboxylic acid ester with a Lewis base in an inert atmosphere and a closed environment, or contacting a carboxylic acid ester with a Lewis base to obtain the carboxylate type ion a liquid, wherein the Lewis base is a tertiary amine type or a tertiary phosphorus type Lewis base, and the temperature of the chemical reaction, or the temperature of the contact, is between the boiling temperature of the carboxylate and the Lewis base. between. The inventors have found that by this method, the halide-free carboxylate-type ionic liquid can be synthesized in a simple and rapid step, the steps are simple, easy to control, the reaction conditions are mild, and the preparation process is short in time, low in energy consumption, and low in cost. . In addition, the prepared ionic liquid can be effectively used to disperse carbon deposits in automobile engines.

According to an embodiment of the invention, the protective atmosphere is nitrogen or an inert gas that does not react with the reaction substrate.

According to an embodiment of the invention, the time of the chemical reaction, or the contact time, is from 0.1 to 240 hours.

According to an embodiment of the invention, the time of the chemical reaction, or the contact time, is 6-72 hours.

According to an embodiment of the invention, the parent acid of the carboxylic acid ester has an acidity coefficient pKa of less than 3.

According to an embodiment of the invention, the parent acid of the carboxylic acid ester has an acidity coefficient pKa of less than 2.3.

According to an embodiment of the invention, the carboxylic acid ester is one selected from the group consisting of:

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently an alkyl group, an aryl group or a polyolefin molecular chain having a molecular weight of less than 3,000,

X is hydrogen or chlorine,

y is 0 or 1.

According to an embodiment of the present invention, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently an alkyl group having 1 to 10 carbon atoms.

According to an embodiment of the invention, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently 2-ethyl-1-hexyl, ethyl or methyl.

According to an embodiment of the invention, the Lewis base is a small molecule compound or a polymer,

Wherein the small molecule compound is an optionally substituted imidazole, an optionally substituted pyrazoline, an optionally substituted thiazole, an optionally substituted pyridine, an optionally substituted pyrrolidine, an optionally substituted pyridazine, optionally Substituted pyrimidine, optionally substituted quinoline, optionally substituted isoquinoline, optionally substituted piperidine, optionally substituted oxazoline, optionally substituted tertiary amine, optionally substituted tertiary phosphine, optionally a substituted pyrazine, an optionally substituted thiazoline, an optionally substituted imidazoline, an optionally substituted triazoline, an optionally substituted 1,4-diazidebicyclo[2.2.2]octane and derivatives thereof Any of them,

The polymer is formed by polymerization of at least one of the following monomers:

Wherein R ₇ is an alkyl group, an aryl group or a polyolefin molecular chain having a molecular weight of less than 3,000.

According to an embodiment of the invention, the small molecule compound is selected from one of the following:

Wherein R ₈ , R ₉ , R ₁₀ and R ₁₁ are each independently H, an alkyl group, an aryl group, or a polyolefin molecular chain having a molecular weight of less than 3,000.

According to an embodiment of the present _{_{invention, R 8, R 9, R}} 10 and R ₁₁ are each independently H or an alkyl group having 1-10 carbon atoms.

According to an embodiment of the invention, R ₈ , R ₉ , R ₁₀ and R ₁₁ are each independently H or n-butyl.

According to an embodiment of the invention, the molar ratio of the carboxylic acid ester to the Lewis base is (0.5-1.5): (0.5-1.5).

According to an embodiment of the invention, the molar ratio of the carboxylic acid ester to the Lewis base is 1:1.

In another aspect of the invention, the invention provides a carboxylate type ionic liquid. According to an embodiment of the invention, the carboxylate type ionic liquid is prepared by the method described above. The inventors have found that such a carboxylate type ionic liquid can be effectively used to disperse carbon deposits in automobile engines.

In still another aspect of the present invention, the present invention provides the use of the carboxylate-type ionic liquid obtained by the above-described method or the carboxylate-type ionic liquid described above for dispersing carbon deposits in automobile engines. The ionic liquid obtained by the method for preparing a carboxylate type ionic liquid of the present invention or the carboxylate type ionic liquid according to the embodiment of the present invention can be used as a dispersing agent for dispersing engine carbon deposits, and the ionic liquid can be effectively used for dispersion. Car engine carbon deposits.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the experimental results of the dispersion stability of an engine ionic liquid and a general commercial detergent dispersant T154A according to an embodiment of the present invention.

detailed description

Embodiments of the present invention are described in detail below. The embodiments described below are illustrative only and are not to be construed as limiting the invention. Where specific techniques or conditions are not indicated in the examples, they are carried out according to the techniques or conditions described in the literature in the art or in accordance with the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are conventional products that can be obtained commercially.

In one aspect of the invention, the invention provides a method of preparing a carboxylate-type ionic liquid. According to an embodiment of the invention, the method comprises: chemically reacting a carboxylic acid ester with a Lewis base in a protective atmosphere and a closed environment, or contacting a carboxylic acid ester with a Lewis base to obtain the carboxylate type ion a liquid, wherein the Lewis base is a tertiary amine type or a tertiary phosphorus type Lewis base, and the temperature of the chemical reaction, or the temperature of the contact is between the boiling temperature of the carboxylate and the Lewis base (standard Measured under atmospheric pressure). The inventors have found that by this method, the halide-free carboxylate-type ionic liquid can be synthesized in a simple and rapid step, the steps are simple, easy to control, the reaction conditions are mild, and the preparation process is short in time, low in energy consumption, and low in cost. . In addition, the prepared carboxylate type ionic liquid can be used as a dispersing agent for dispersing engine carbon deposits, and the ionic liquid can be effectively used for dispersing carbon deposits in automobile engines.

According to an embodiment of the invention, it is preferred to contact the carboxylic acid ester with a tertiary amine or tertiary phosphorus Lewis base in a closed vessel. Thereby, the closed environment can effectively promote the reaction equilibrium to proceed in the forward direction, so that the yield of the ionic liquid can be remarkably improved. Specifically, the air in the container can be discharged by passing the shielding gas, and then the container is sealed for reaction. According to some embodiments of the present invention, the protective atmosphere is not particularly limited, and those skilled in the art can flexibly select according to needs. In some embodiments of the invention, the protective atmosphere may be nitrogen or an inert gas. Thereby, the reaction can be smoothly carried out, the reactant can be effectively protected from oxidation, and the price is low. It should be noted that the term "inert gas" as used herein refers to a gas that does not react with a reaction substrate, such as a rare gas, including helium, neon, argon, helium, neon, and the like.

According to an embodiment of the invention, the carboxylic acid ester can be reacted or contacted with a Lewis base for 0.1 to 240 hours. In some embodiments of the invention, the carboxylic acid ester can be reacted or contacted with a Lewis base for 6-72 hours. Thereby, it is possible to effectively ensure that the reaction is sufficiently performed without wasting time due to excessive time.

According to some embodiments of the invention, the parent acid of the carboxylic acid ester employed in the process has an acidity coefficient of less than 3. That is, the parent acid of pK _a of carboxylic acid ester value of less than 3. According to other embodiments of the present invention, the coefficient of acidity of the parent acid carboxylic acid ester used in the process is less than 2.3, i.e., the parent acid of pK _a of carboxylic acid ester value of less than 2.3. In the method for preparing a carboxylate type ionic liquid of the present invention, the pK _a value of the parent acid of the carboxylic acid ester dominates the reaction, and the pK _a value of the parent acid of the carboxylic acid ester is controlled within the above range, and the ionic liquid can be remarkably improved. Yield.

According to an embodiment of the present invention, the carboxylic acid ester used may be one selected from the group consisting of:

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently an alkyl group, an aryl group or a polyolefin molecular chain having a molecular weight of less than 3000, X is hydrogen or chlorine, and y is 0 or 1 . By using the above carboxylic acid ester, the acidity coefficient of the parent acid satisfies the requirement of less than 2.3, the reaction can be effectively promoted, and the obtained ionic liquid has better usability.

In some embodiments of the invention, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently an alkyl group having from 1 to 10 carbon atoms. In still other embodiments of the invention, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently 2-ethyl-1-hexyl, ethyl or methyl. Thereby, the progress of the reaction can be further promoted, and the usability of the obtained ionic liquid can be improved.

According to an embodiment of the present invention, the Lewis base is a small molecule compound or a polymer, wherein the small molecule compound is an optionally substituted imidazole, an optionally substituted pyrazoline, an optionally substituted thiazole, optionally substituted Pyridine, optionally substituted pyrrolidine, optionally substituted pyridazine, optionally substituted pyrimidine, optionally substituted quinoline, optionally substituted isoquinoline, optionally substituted piperidine, optionally substituted An oxazoline, an optionally substituted tertiary amine, an optionally substituted tertiary phosphine, an optionally substituted pyrazine, an optionally substituted thiazoline, an optionally substituted imidazoline, an optionally substituted triazoline, an optionally substituted 1 Any one of 4-diazidebicyclo[2.2.2]octane and a derivative thereof; the polymer is formed by polymerization of at least one of the following monomers:

According to an embodiment of the present invention, the above small molecule compound Lewis base may be one of the following:

Wherein R ₈ , R ₉ , R ₁₀ and R ₁₁ are each independently H, an alkyl group, an aryl group, or a polyolefin molecular chain having a molecular weight of less than 3,000. The above Lewis base can be effectively reacted with a carboxylic acid ester to obtain an ionic liquid, and the obtained ionic liquid has better usability.

In some embodiments of the invention, R ₈ , R ₉ , R ₁₀ and R ₁₁ are each independently H or an alkyl group having from 1 to 10 carbon atoms. In other embodiments of the invention, R ₈ , R ₉ , R ₁₀ and R ₁₁ are each independently H or n-butyl. Thereby, the usability of the obtained ionic liquid can be further improved.

According to some embodiments of the invention, the molar ratio of the carboxylic acid ester to the Lewis base is (0.5-1.5): (0.5-1.5). According to further embodiments of the invention, the molar ratio of the carboxylic acid ester to the Lewis base is 1:1. Within the above ratio range, the carboxylic acid ester and the Lewis base can be sufficiently reacted, which is advantageous for improving the reaction efficiency and yield.

In still another aspect of the present invention, the present invention provides the use of the carboxylate-type ionic liquid prepared by the method described above for dispersing carbon deposits in automobile engines. The ionic liquid prepared by the method for preparing a carboxylate type ionic liquid of the present invention can be used as a dispersing agent for dispersing engine carbon deposits, and the ionic liquid can be effectively used for dispersing carbon deposits in automobile engines.

Embodiments of the present invention are described in detail below.

Example 1: Preparation of [1-butyl-3-isooctyl-imidazole][1,2,4-tris(isooctylcarboxylate)-5-benzoate] salt

70.3 g of tetraisooctyl pyromellitate (CAS No. 3126-80-5, M _w = 703 g/mol) and 12.42 g of 1-butylimidazole (CAS No. 4316-42-1, M _w = 124.18) G/mol) was mixed and the resulting mixture was sealed into a Teflon-lined pressure tube with a colorless, transparent, low viscosity liquid. Before the reaction, nitrogen gas was introduced into the pressure tube to remove the air, and then heated to 130 ° C to 135 ° C and held for 48 hours. After the reaction was completed, the mixture became a viscous liquid and the color was pale brownish red. The reaction product is [1-butyl-3-isooctyl-imidazole][1,2,4-tris(isooctylcarboxylate)-5-benzoate] salt, containing a small amount of 1-butylimidazole and both Tetraisooctyl benzoate. The chemical reaction equation of this example is shown below.

Example 2: Preparation of [1-butyl-3-isooctyl-imidazole][1-carboxylic acid isooctyl ester-2-acrylate] salt

68.1 g of diisooctyl maleate (CAS No. 42-16-5, M _w = 340.5 g/mol) and 24.94 g of 1-butylimidazole (CAS No. 4316-42-1, M _w = 124.18) g/mol), and the resulting mixture is sealed into a Teflon-lined pressure tube. The mixture is a colorless, transparent, low-viscosity liquid. Before the reaction, nitrogen is introduced into the pressure tube to remove the air, and then heated to The mixture was kept at 130 ° C to 135 ° C for 48 hours. After the reaction was completed, the mixture was a viscous liquid and the color was pale brownish red. The reaction product was a salt of [1-butyl-3-isooctyl-imidazole][1-carboxylic acid isooctyl-2-carboxylate], and the product contained a small amount of 1-butylimidazole and diisooctyl maleate. The chemical reaction equation of this example is shown below.

Example 3: Preparation of [1-butyl-3-ethyl-imidazole][1-formic acid ethyl ester-formate] salt

29.2 g of diethyl oxalate (CAS No. 95-92-1, M _w = 146.14 g/mol) and 24.94 g of 1-butylimidazole (CAS No. 316-42-1, M _w = 124.18 g/mol Mixing and sealing the obtained mixture into a Teflon-lined pressure tube. The mixture is a colorless, transparent, low-viscosity liquid. Before the reaction, nitrogen gas is introduced into the pressure tube to remove the air, and then heated to 130 ° C. The mixture was incubated at 135 ° C for 48 hours. After the reaction was completed, the mixture was a viscous liquid and the color was pale brownish red. The reaction product was a salt of [1-butyl-3-ethyl-imidazole][1-carboxylate-formate], and the product contained a small amount of 1-butylimidazole and ethyl oxalate. The chemical reaction equation of this example is shown below.

Example 4: Preparation of [1-butyl-3-methyl-imidazole][1-formic acid methyl ester-formate] salt

23.6 g of dimethyl oxalate (CAS No. 553-90-2, M _w = 118.09 g/mol) and 24.94 g of 1-butylimidazole (CAS No. 4316-42-1, M _w = 124.18 g/mol Mixing and sealing the obtained mixture into a Teflon-lined pressure tube. The mixture is a colorless, transparent, low-viscosity liquid. Before the reaction, nitrogen gas is introduced into the pressure tube to remove the air, and then heated to 130 ° C. The mixture was incubated at 135 ° C for 48 hours. After the reaction was completed, the mixture was a viscous liquid and the color was pale brownish red. The reaction product was a salt of [1-butyl-3-methyl-imidazole][1-formic acid methyl ester-formate], and the product contained a small amount of 1-butylimidazole and dimethyl oxalate. The chemical reaction equation of this example is shown below.

Example 5: Synthetic Carboxylate Ionic Liquid for Dispersing Engine Carbon

The test sample preparation process is as follows:

(1) Weighing 0.1 g (0.5% by weight) of carbon deposit formed from a diesel engine was placed in a 25 ml glass bottle A. Then, 250 SN mineral oil was added to the glass bottle A so that the total mass of the mixture was 20 g.

(2) Weighing 0.1 g (0.5% by weight) of carbon deposit formed from the diesel engine was placed in a 25 ml glass bottle B. Then, 0.2 g (1% by weight) of a general commercial detergent dispersant T154A (chemical composition of polyisobutenyl succinimide) was added to the vial B. 250 SN mineral oil was added to glass bottle B so that the total mass of the mixture was 20 g.

(3) Weighing 0.1 g (0.5% by weight) of carbon deposit formed from the diesel engine was placed in a 25 ml glass bottle C. Then, the ionic liquid [1-butyl-3-isooctyl-imidazole] [1,2,4-tris(isooctylesterate)-5-benzoic acid prepared in Example 1 was added to the vial C. Root] salt 0.1 g (0.5% by weight), and the ionic liquid [1-butyl-3-isooctyl-imidazole][1-carboxylic acid isooctyl ester-2-acrylate] salt prepared in Example 2 0.1 g (0.5% by weight), 250 SN mineral oil was added to the glass bottle C so that the total mass of the mixture was 20 g.

(4) First, the mixture in the glass bottle A, the glass bottle B, and the glass bottle C was shaken separately, and then ultrasonically treated (frequency 40 KHz, power 150 W) for 10 minutes.

(5) The ultrasonically treated glass bottle A, glass bottle B, and glass bottle C were left to stand. The experimental results after standing for different lengths of time are shown in Fig. 1. In Fig. 1, (A) is a schematic diagram of the effect of dispersing the engine carbon deposit of 0.5% by mass into 250 SN mineral oil without adding a detergent dispersant, and after ultrasonic treatment, after standing for one day. (B) Schematic diagram of the effect of dispersing the carbon deposit of the engine with a mass fraction of 0.5% into 250SN mineral oil, adding the ordinary commercial detergent dispersant T154A with a mass fraction of 0.1%, and after ultrasonic treatment, after standing for seven days. (C) To disperse engine carbon deposits with a mass fraction of 0.5% into 250SN mineral oil, add 0.5% by mass of ionic liquid [1-butyl-3-isooctyl-imidazole] [1,2,4-three (Isooctylcarboxylate)-5-benzoate] salt and 0.5% by mass of ionic liquid [1-butyl-3-isooctyl-imidazole][1-carboxylic acid isooctyl ester-2-acrylate Salt, after ultrasonic treatment, the effect of rest after one year of standing.

For the engine carbon deposition, the more uniform the dispersing agent disperses the carbon deposit and the longer the sedimentation time, indicating that the anti-carbon deposition performance of the additive is better. According to the experimental results shown in FIG. 1, it can be seen that after adding the ionic liquid prepared by the invention for one year, the engine carbon deposit still has very good dispersion stability in the 250 SN mineral oil, and the ionic liquid prepared by the invention can be As a highly efficient dispersant for dispersing engine carbon deposits.

In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include one or more of the features either explicitly or implicitly. In the description of the present invention, the meaning of "a plurality" is two or more unless specifically and specifically defined otherwise.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. , structure, material or feature package It is included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

Although the embodiments of the present invention have been shown and described, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the invention. The embodiments are subject to variations, modifications, substitutions and variations.

Claims

A method for preparing a carboxylate type ionic liquid, comprising:

Chemically reacting a carboxylic acid ester with a Lewis base under a protective atmosphere and a sealed environment to obtain the carboxylate type ionic liquid,

Wherein the Lewis base is a tertiary amine type or a tertiary phosphorus type Lewis base,

The temperature of the chemical reaction is between the boiling temperatures of the carboxylic acid ester and the Lewis base.
The method of claim 1 wherein said protective atmosphere is nitrogen or an inert gas that does not react with the reaction substrate.
The method according to claim 1 or 2, wherein the chemical reaction is carried out for a period of from 0.1 to 240 hours.
The method of claim 3 wherein said chemical reaction is carried out for a period of from 6 to 72 hours.
The method according to any one of claims 1 to 4, wherein the parent acid of the carboxylic acid ester has an acidity coefficient pKa of less than 3.
The method of claim 5 wherein the parent acid of the carboxylic acid ester has an acidity coefficient pKa of less than 2.3.
The method according to claim 6, wherein the carboxylic acid ester is at least one selected from the group consisting of:

Wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently an alkyl group, an aryl group or a polyolefin molecular chain having a molecular weight of less than 3,000,

X is hydrogen or chlorine,

y is 0 or 1.
The method according to claim 7, wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently an alkyl group having 1 to 10 carbon atoms.
The method according to claim 8, wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently 2-ethyl-1-hexyl, ethyl or methyl.
The method according to any one of claims 1 to 9, wherein the Lewis base is a small molecule compound or a polymer.

Wherein the small molecule compound is an optionally substituted imidazole, an optionally substituted pyrazoline, an optionally substituted thiazole, an optionally substituted pyridine, an optionally substituted pyrrolidine, an optionally substituted pyridazine, optionally Substituted pyrimidine, optionally substituted quinoline, optionally substituted isoquinoline, optionally substituted piperidine, optionally substituted oxazoline, optionally substituted tertiary amine, optionally substituted tertiary phosphine, optionally a substituted pyrazine, an optionally substituted thiazoline, an optionally substituted imidazoline, an optionally substituted triazoline, an optionally substituted 1,4-diazidebicyclo[2.2.2]octane and derivatives thereof Any of them,

The polymer is formed by polymerization of at least one of the following monomers:

Wherein R 7 is an alkyl group, an aryl group or a polyolefin molecular chain having a molecular weight of less than 3,000.
The method according to claim 9, wherein said small molecule compound is one selected from the group consisting of:

Wherein R 8 , R 9 , R 10 and R 11 are each independently H, an alkyl group, an aryl group, or a polyolefin molecular chain having a molecular weight of less than 3,000.
The method according to claim 11, wherein R 8 , R 9 , R 10 and R 11 are each independently H or an alkyl group having 1 to 10 carbon atoms.
The method of claim 12 wherein R 8 , R 9 , R 10 and R 11 are each independently H or n-butyl.
The method according to any one of claims 1 to 13, wherein the molar ratio of the carboxylic acid ester to the Lewis base is (0.5 - 1.5): (0.5 - 1.5).
The method of claim 14 wherein the molar ratio of the carboxylic acid ester to the Lewis base is 1:1.
A carboxylate type ionic liquid prepared by the method according to any one of claims 1-15.
Use of the method according to any one of claims 1 to 15 for preparing a carboxylate-type ionic liquid or the carboxylate-type ionic liquid of claim 16 for dispersing carbon deposits in an automobile engine.