KR101210511B1 - Purification Method of Ionic Liquid using Refrigerants - Google Patents

Abstract

The present invention comprises the steps of mixing the ionic liquid and the liquid refrigerant before purification; Extracting the refrigerant and the ionic liquid mixture; And vaporizing the refrigerant in the refrigerant and the ionic liquid mixture. It relates to a method for purifying an ionic liquid comprising a.
INDUSTRIAL APPLICABILITY The present invention is a technique for effectively removing a by-product salt or a large amount of water generated after preparation or use of an ionic liquid. Is possible.

Description

Purification Method of Ionic Liquid Using Refrigerant

The present invention relates to a method for purifying an ionic liquid using a refrigerant.

The purification technology of ionic liquids is very closely related to the problem of ionic liquid and product recovery in the field of application. This is because the ionic liquid has almost no vapor pressure, so it is difficult to solve the recovery problem easily by the conventional separation method. This is because the purpose of using the ionic liquid is undermined. In order to solve this problem, supercritical or subcritical carbon dioxide is used, but in this case, the purpose is to recover a product having thermal instability or an organic product having a high boiling point in an ionic liquid. There is this.

In the case of designing and synthesizing ionic liquids hydrophobicly, they may be somewhat free from these problems, but there are problems in terms of purification yield. In the case of ionic liquids having hydrophobicity due to the kind of anions, they do not mix with water, and phase separation occurs at a specific molar ratio. Therefore, even in the case of hydrophobic ionic liquids, there is a problem in yield in removing by-product acids or salts.

Accordingly, there is a need for the development of purification techniques using new media for the effective removal of byproduct acids or salts present in hydrophilic ionic liquids.

It is an object of the present invention to overcome the above problems, to remove by-products generated in the manufacture or use of ionic liquids, and to provide a more efficient purification technology to obtain a high purity ionic liquid.

The present invention to solve the above problem, the step of mixing the ionic liquid and the liquid refrigerant before purification; Extracting the refrigerant and the ionic liquid mixture; And vaporizing the refrigerant; It provides a method for purifying an ionic liquid comprising a.

INDUSTRIAL APPLICABILITY The present invention is a technique for effectively removing a by-product salt or a large amount of water generated after preparation or use of an ionic liquid. Is possible. This effect of the present invention will be a great contribution to securing the competitiveness of the ionic liquid application process.

FIG. 1 is a phase diagram of a three-phase system for C ₈ H ₁₅ BF ₄ N ₂ and water, and R22 (A) and R134a (B) refrigerants.
FIG. 2 is a phase diagram of three-phase balance for C ₈ H ₁₅ ClN ₂ , water, and R22 (A) and R134a (B) refrigerants.
FIG. 3 is a phase diagram of the three-phase system for C ₁₀ H ₁₈ N ₂ O ₂ , water, and R22 (A) and R134a (B) refrigerants.
FIG. 4 is a phase diagram of a ternary system for C ₈ H ₁₅ BrN ₂ , water, and R22 (A) and R134a (B) refrigerants.
FIG. 5 is a phase diagram of three-phase summaries for C ₆ H ₁₁ BF ₄ N ₂ , water, and R22 (A) and R134a (B) refrigerants.
FIG. 6 is a phase diagram of a ternary system for C ₆ H ₁₁ BrN ₂ , water, and R22 (A) and R134a (B) refrigerants.
FIG. 7 is a phase diagram of phase difference for C ₈ H ₁₄ N ₂ O ₂ , water, and R22 (A) and R134a (B) refrigerants.
FIG. 8 is a phase diagram of phase difference for C ₈ H ₁₈ N ₂ O ₄ S, water, and R22 (A) and R134a (B) refrigerants.
FIG. 9 is a phase diagram of three-phase balance for C ₇ H ₁₁ F ₃ N ₂ O ₃ S, water, and R22 (A) and R134a (B) refrigerants.
10 shows the results of ternary phase equilibrium and ionic liquid chromatography (ILC) analysis in Example 1. FIG.
FIG. 11 shows the Samsung system phase equilibrium and ILC analysis results in Example 2. FIG.
FIG. 12 shows the Samsung system phase equilibrium and ILC analysis results in Example 3. FIG.
FIG. 13 shows the Samsung system phase equilibrium and ILC analysis results in Example 4. FIG.

The present invention seeks to provide a method for effectively removing by-product salts or large amounts of water generated after the preparation or use of ionic liquids. The effective purification of by-product salts generated in the synthesis of ionic liquids is particularly important for hydrophilic ionic liquids. The purpose of the present invention is to provide a hydrophilic ionic liquid separation / purification technology by using a new medium to separate the ionic liquid, by-product salt and water. The hydrophilic ionic liquid may be an imidazolium-based, ammonium-based, choline-based, phosphonium-based, sulfonium-based, pyridinium-based, pyrazolium-based ionic liquids, and the like.

Specifically, the present invention comprises the steps of mixing the ionic liquid and the liquid refrigerant before purification; Extracting the refrigerant and the ionic liquid mixture; And vaporizing the refrigerant in the refrigerant and the ionic liquid mixture. It relates to a method for purifying an ionic liquid comprising a.

The ionic liquid before purification is a mixture of ionic liquid, water and by-product salt. In the present invention, the ionic liquid is purified to obtain a pure ionic liquid.

In the step of mixing the ionic liquid and the liquid refrigerant before the purification, the condition pressure is preferably a pressure for liquefying the refrigerant, that is, 7 to 15 atm.

By mixing the coolant and increasing the amount of the coolant, liquid-liquid extraction is possible by separating the mixed liquid of the coolant and the ionic liquid and the mixed liquid of the water and the by-product salt into two phases. In the following experimental examples, the three-phase phase diagram for the refrigerant and water of various ionic liquids is shown.

In the extracted refrigerant and the ionic liquid mixture, the pressure may be lowered to 0.1 to 2 atm to vaporize the refrigerant, thereby obtaining a pure ionic liquid.

The refrigerant used in the present invention has excellent solubility in ionic liquids and thus selectively extracts only ionic liquids from water, by-product salts and ionic liquid mixtures using such refrigerants. In addition, the refrigerant is a gas at room temperature and a material that can be easily liquefied. Liquefaction is carried out under a pressure of 7 to 15 atm, allowing ionic liquid aqueous solution and liquid-liquid extraction. In addition, the ionic liquid and the refrigerant can be easily separated by only lowering the pressure to 0.1 to 2 atmospheres after extraction, and the separated refrigerant can be reused by liquefying by pressurization. The refrigerant is not particularly limited, such as CFC-based refrigerants, HCFC-based refrigerants, HFC-based refrigerants, or a mixture thereof, but in particular, R22, R134 or a mixture thereof may be used.

Hereinafter, the present invention will be described in more detail with reference to examples, but the following examples are merely to illustrate the present invention, but it should be understood that the present invention is not limited thereto.

Experimental Example  : Samsung Demarcation Phase diagram  suggest

The reactor was fabricated using tempered glass withstanding pressure. After a certain amount of ionic liquid and water were added to the reactor, the refrigerant was slowly injected and the clouding point was measured. The amount of refrigerant injected at the moment when the clouding point was made was measured, and its composition was shown in the Samsung meter in molar ratio. The turbidity point was obtained by repeating the above experiment by changing the amount of ionic liquid and water and changing the type of refrigerant (R22, R134a).

The three-phase equilibrium diagram was obtained by changing the type of ionic liquid shown in Table 1, which is shown in FIGS.

Ionic liquid Abbreviation Chemical formula 1 1-Buthyl-3-methylimidazolium tetrafluoroborate BMImBF ₄ C ₈ H ₁₅ BF ₄ N ₂ 2 1-Buthyl-3- methylimidazolium chloride BMImCl C ₈ H ₁₅ ClN ₂ 3 1-Buthyl-3-
methylimidazolium
acetate BMImAc C ₁₀ H ₁₈ N ₂ O ₂ 4 1-Butyl-3-methylimidazolium bromide BMImBr C ₈ H ₁₅ BrN ₂ 5 1-ethyl-3-methylimidazolium tetrafluoroborate EMImBF ₄ C ₆ H ₁₁ BF ₄ N ₂ 6 1-ethyl-3-methylimidazolium bromide EMImBr C ₆ H ₁₁ BrN ₂ 7 1-ethyl-3-methylimidazolium acetate EMImAc C ₈ H ₁₄ N ₂ O ₂ 8 1-ethyl-3-methylimidazolium ethylsulfate EMImEtOSO ₄ C ₈ H ₁₆ N ₂ O ₄ S 9 1-ethyl-3-methylimidazolium trifluoromethanesulfate EMImMtSO ₃ C ₇ H ₁₁ F ₃ N ₂ O ₃ S

Example  One

The reactor was fabricated using tempered glass withstanding pressure. 8.99 grams of 1-butyl-3-methyl-imidazolium-tetrafluoro borate (BMImBF ₄ ), which is an imidazolium-based ionic liquid, was charged. Subsequently, 6.73 grams of an aqueous 1000 ppm lithium chloride (LiCl) solution known as a byproduct salt of the ionic liquid was optionally prepared and added. After confirming that the ionic liquid and the aqueous solution form a homogeneous phase, the mixture was stirred, and 34 grams of the liquid R22 was added at 10 atmospheres to adjust the composition to the two phase region of phase equilibrium. R22 began to undergo phase separation with the ionic liquid. The mixture of R22 and the ionic liquid was extracted at 10 atmospheres. 10 is a result of analyzing the aqueous phase (Aq. Phase) and the refrigerant and the ionic liquid mixture layer (IL phase) after phase separation by changing the composition in the direction of the arrow by ILC, respectively. It was confirmed that no chlorine ions were detected in the refrigerant and the ionic liquid mixture layer.

Finally, the mixture of extracted R22 and the ionic liquid was vaporized R22 at a pressure of 1 atmosphere to obtain a pure ionic liquid.

Example  2

The reactor was fabricated using tempered glass withstanding pressure. 8.83 grams of 1-butyl-3-methyl-imidazolium-tetrafluoro borate (BMImBF ₄ ), which is an imidazolium-based ionic liquid, was charged. Subsequently, 9.73 grams of an aqueous 1000 ppm lithium chloride (LiCl) solution known as a byproduct salt of the ionic liquid was optionally prepared and added. After confirming that the ionic liquid and the aqueous solution form a homogeneous phase, the mixture was stirred and the composition was adjusted to a two-phase region of phase equilibrium by adding 8.36 grams of R134a in the liquid phase at 10 atm. R134a began to undergo phase separation with the ionic liquid. The mixture of R134a and the ionic liquid was extracted at 10 atmospheres. 11 is a result of analyzing the aqueous phase (Aq. Phase) and the refrigerant and the ionic liquid mixed solution (IL phase) by ILC after phase separation by changing the composition in the direction of the arrow. It was confirmed that no chlorine ions were detected in the refrigerant and the ionic liquid mixture layer.

Finally, the mixture of extracted R134a and the ionic liquid was vaporized R134a at a pressure of 1 atm to obtain a pure ionic liquid.

Example  3

The reactor was fabricated using tempered glass withstanding pressure. 7.31 grams of 1-ethyl-3-methyl-imidazolium-tetrafluoro borate (EMImBF ₄ ), which is an imidazolium-based ionic liquid, was charged. Subsequently, 8.26 grams of an aqueous 1000 ppm lithium chloride (LiCl) solution known as a byproduct salt of the ionic liquid was optionally prepared and added. After confirming that the ionic liquid and the aqueous solution form a homogeneous phase, the mixture was stirred and 13.7 grams of the liquid R22 was added at 10 atmospheres to adjust the composition to the two-phase region of phase equilibrium. R22 began to undergo phase separation with the ionic liquid. The mixture of R22 and the ionic liquid was extracted at 10 atmospheres. 12 is a result of analyzing the aqueous phase (Aq. Phase), the refrigerant and the ionic liquid mixture (IL phase) by ILC after phase separation by changing the composition in the direction of the arrow. It was confirmed that no chlorine ions were detected in the refrigerant and the ionic liquid mixture layer.

Finally, the mixture of R22 and the ionic liquid was evaporated R22 at a pressure of 1 atmosphere to obtain a pure ionic liquid.

Example  4

The reactor was fabricated using tempered glass withstanding pressure. 7.8 grams of 1-ethyl-3-methyl-imidazolium-trifluoromethanesulfonate (EMImMtSO ₃ ), which is an imidazolium-based ionic liquid, was added to the reactor. Then 8.53 grams of an aqueous 1000 ppm lithium chloride (LiCl) solution, known as a byproduct salt of the ionic liquid, was optionally prepared and added. After confirming that the ionic liquid and the aqueous solution form a homogeneous phase, the mixture was stirred, and 14.4 grams of R22 in the liquid phase were added at 10 atm to adjust the composition to the two phase region of phase equilibrium. R22 began to undergo phase separation with the ionic liquid. The mixture of R22 and the ionic liquid was extracted at 10 atmospheres. 13 is a result of analyzing the aqueous phase (Aq. Phase), the refrigerant and the ionic liquid mixture (IL phase) by ILC after phase separation by changing the composition in the direction of the arrow. It was confirmed that no chlorine ions were detected in the refrigerant and the ionic liquid mixture layer.

Finally, the mixture of R22 and the ionic liquid was evaporated R22 at a pressure of 1 atmosphere to obtain a pure ionic liquid.

Claims (5)

delete (1) mixing a liquid refrigerant selected from the group consisting of a CFC refrigerant, an HCFC refrigerant, an HFC refrigerant, or a mixture thereof to the ionic liquid before purification;
(2) extracting the refrigerant and the ionic liquid mixture; And
(3) vaporizing the refrigerant in the refrigerant and the ionic liquid mixture;
Purification method of the ionic liquid comprising a.
3. The method of claim 2, wherein the refrigerant is R-22, R-134 or a mixture thereof.
The ionic liquid is purified according to claim 2, wherein the ionic liquid is an imidazolium-based, ammonium-based, choline-based, phosphonium-based, sulfonium-based, pyridinium-based, or pyrazolium-based ionic liquid. Way.
The method of claim 2, wherein the pressure in steps (1) and (2) is 7 to 15 atmospheres and the pressure in step (3) is 0.1 to 2 atmospheres.

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