KR101279607B1 - Synthesis of Carboxylic acid anion-Ionic Liquids with Metal free Using Microreactor - Google Patents

Abstract

The present invention relates to a continuous production of a hydrophilic ionic liquid having a carboxylic acid as an anion, using a microreactor selectively safe in order to solve the exothermic risk and human risk during the reaction.
The ionic liquid obtained through this method has an improved synthesis yield of more than 85%, a trace amount of halide, which is chemical purity, is less than 20 ppm, and the synthesis method without residual metal reduces the production cost. will be.

Description

Synthesis of Carboxylic acid anion-Ionic Liquids with Metal free Using Microreactor

This invention relates to the manufacturing method of the ionic liquid which has a high purity carboxylic acid anion with little halide content. More specifically, the present invention uses an intermediate ionic liquid having a microreactor, methylsulfonate or trichloromethanesulfonate as an anion, and a non-metal acetate compound to contain a metal-free carboxylic acid anion containing less than 20 ppm of halide. The present invention relates to an economical method for preparing an ionic liquid having a high yield of 85% or more.

An ionic liquid at room temperature, based on 1,3-dialkylimidazolycol cation, was first reported by Wikes et al. In 1982. This ionic liquid has chloroaluminate anions and has many useful properties such as wide liquid range, thermal stability and wide potential window, but it reacts with specific materials and is very sensitive to moisture. Air and water stable ionic liquids were developed by Wolkes and Zaworotko based on tetrafluoroborate anions in 1992, and since then a wide range of ionic liquids with different anions have been reported.

The main impurities generated in the synthesis of ionic liquids are organic halide salts, organic salts, residual halides, residual acids, excess alkali metals, etc. In particular, halide ions are easily combined with components of the ionic liquid to It is not easy to remove it completely. In general, halides are fluoride, chloride, bromide, iodine, residual acid is hydrogen sulfonate, hydrogen carbonate, trifluoroacetic acid, triflate, hydrogen halide, and alkali metal is potassium, sodium and the like.

Conventional methods of preparing ionic liquids mainly involve the use of halide compounds (Cl, Br, I) and metal oxide catalysts. Thus, this method produces ionic liquids with high residual amounts of metals and halides. In addition, ionic liquids having carboxylic acid anions are water soluble, and thus high purity ionic liquids could not be obtained when metal or halide compounds were present in the preparation.

Therefore, there has been a need in the art for a method for preparing an ionic liquid having a high purity metal free carboxylic acid anion having a low halide content without using a halide compound and a metal oxide catalyst.

In order to solve the problems of the prior art as described above, the present inventors have consistently found that when using a specific intermediate ionic liquid and a microreactor, ions having high purity carboxylic acid as an anion without using a halide compound and a metal oxide catalyst It was confirmed that the liquid can be prepared and the present invention was completed.

It is therefore an object of the present invention to provide a method for producing an ionic liquid having a high purity carboxylic acid as anion having a residual halide content of less than 20 ppm and no residual metal.

In order to achieve the object of the present invention, the present invention is a method for preparing an ionic liquid having high purity carboxylic acid as an anion, comprising reacting a cation-providing intermediate ionic liquid with an anion-providing acetate compound in a microreactor. Provide a way to.

The ionic liquid synthesized in the production method of the present invention may be further filtered and concentrated under reduced pressure.

In the preparation method of the present invention, the cation-providing intermediate ionic liquid is an ionic liquid having methylsulfonate or trilomethanesulfonate as an anion, and the anion-providing acetate compound includes ammonium acetate, potassium acetate, sodium acetate and the like. .

Cation-providing intermediate ionic liquids and anion-providing acetate compounds can be synthesized on the reaction solvent. Examples of reaction solvents that can be used include alcohol solvents such as methanol, ethanol, propanol, ethylene glycol, methyl acetate, ethyl acetate, propyl acetate, γ-butyrolactone, ester solvents such as propion carbonite, acetonitrile, propionitrile, and the like. Nitrile solvents, aromatic solvents such as benzene, toluene, xylene, N, N-dimethylformamide, dimethyl sulfoxide and the like. The reaction solvent is used alone or as a mixture of any two or more kinds.

The reaction is done in a microreactor. The microreactor has several micrometers for the flow path of the fluid, rapid heating and cooling, laminar flow, and large surface area per unit volume, so that the diffusion of the material is short. It is characterized by (FIGS. 2 and 3). In the present invention, a conventionally used microreactor having safety in chemical reactions may be used (FIG. 1).

In the preparation method of the present invention, the amount of the cation-providing intermediate ionic liquid is preferably 0.0005 mol to 1.0 mol, and when it exceeds 1.0 mol, a product which does not participate in the reaction is generated and becomes an unreacted substance. Is fast but yield is low. The flow rate to the microreactor is preferably 0.01ml / min ~ 2.0ml / min. If the amount exceeds 2.0ml / min, the flow rate becomes faster and the reaction conversion rate is lowered. Therefore, unreacted substances are generated and must be reacted again. If the amount is less than 0.01ml / min, the flow rate is too slow.

The amount of the anion-providing acetate compound is preferably 0.0005 moles to 1.0 moles, and when it exceeds 1.0 moles, a product that does not participate is generated and is a by-product to be removed. The flow rate to the microreactor is preferably 0.01ml / min ~ 2.0ml / min. If the amount exceeds 2.0ml / min, the flow rate will be faster and unreacted substances will be generated and re-reacted. If the amount is less than 0.01ml / min, the flow rate will be too slow to complete the reaction.

The reaction temperature (the temperature of the microreactor) is preferably 0 to 100 ° C. If the temperature is over 100 ° C, the formation of by-products and decomposition products is promoted, and the color is dark, making it difficult to remove. do. The reaction time is preferably 0.5 to 24 hours. If it is more than 24 hours, by-products are formed, the color becomes dark, so that it is difficult to remove, and the reaction does not proceed anymore. If the reaction time is less than 0.5 hours, unreacted substances exist and the reaction completion rate is low.

Further reduced pressure concentration of the product may be carried out for 1 to 2 hours at an internal temperature of 50-60 ° C under 1 atmosphere. When concentrating, 755 ~ 760torr should be maintained. If the internal temperature of the concentrate is high, the compound with low thermal stability generates decomposition products and becomes dark in color.The compound with low thermal stability generates decomposition products or loses color even after long concentration time. It will darken. When the concentration is lower than 755torr, the concentration efficiency is lowered, and the residual solvent and water remain, and the residual solvent and water remain, even when the inner temperature of the concentrate is low or the concentration time is short.

According to the production method of the present invention, an ionic liquid having a carboxylic acid anion having a halide content of less than 20 ppm could be continuously and safely obtained by a microreactor.

According to the production method of the present invention, an ionic liquid having a residual halide content of less than 20 ppm and a residual metal free (metal free) carboxylic acid as an anion can be continuously and safely produced by a microreactor.

In addition, the production method of the ionic liquid according to the present invention is a synthetic method of improving the stability of the reaction, the yield is higher than 85%, containing a trace amount of halide and the purity of the ionic liquid without residual metal, and scale-up It is easy to reduce the cost of design, investment and operation, and saves raw materials, solvents, waste and energy.

Figure 1 shows the overall arrangement of the microreactor synthesis apparatus.
2 is a synthetic circuit diagram illustrating a process of becoming a target compound through a micro mixer when reagents A and B are flowed through a syringe pump to a microreactor.
3 shows Y type, Helix type and Static type, which are types of micromixers.
4 is a 716 DMS Titrino ion analyzer which is a halide measuring apparatus.

In the following Examples, the present invention will be described in more detail, but the present invention is not limited thereto.

<Device used>

The microreactor used Keychem L of YMC, Japan, and MRSY04-40 for the cylinder pump, and the Helix type for the micromixer, which has excellent heat exchange and stirring properties and is suitable for organic synthesis.

<Measurement of Residual Halides>

Metrohm 716 DMS Titrino ion spectrometer was used, and the residual halide was measured by the standard method.

<Production Example>

Example  1: 1-ethyl-3- Methylimidazolium  Acetate

1.2 g (0.0056 mol) of 1-ethyl-3-methylimidazolium methyl sulfate was dissolved in methanol at 0.3 ml / min, and 0.43 g (0.0056 mol) of ammonium acetate was dissolved in methanol at 70 DEG C at 0.23 ml / min. Flow through the controlled microreactor cylinder pump.

The solution that passed through the microreactor was collected, and the precipitated byproduct was removed by filtration, and then concentrated under reduced pressure (1 atm, 60 DEG C, 1 hour) to obtain the target compound.

Yield: 0.82 g, yield 86%, residual halide 12 ppm.

Example  2: 1-butyl-3- Methylimidazolium  Acetate

1.4 g (0.0059 mol) of 1-butyl-3-methylimidazolium methyl sulfate was dissolved in methanol at 0.5 ml / min, and 0.45 g (0.0059 mol) of ammonium acetate was dissolved in methanol at 40 ° C. at 0.45 ml / min. Flow through the controlled microreactor cylinder pump.

The solution passed through the microreactor was collected, and the precipitated byproduct of the reaction mixture was removed from the solution by filtration, and then concentrated under reduced pressure (1 atm, 60 ° C, 1 hour) to obtain the target compound.

Yield: 1.0 g, yield: 90%, residual halide: 8 ppm.

Example  3: 1-ethyl-3- Methylimidazolium  Acetate

0.3 g (0.0015 mol) of 1-ethyl-3-methylimidazolium triflomethanesulfonate was dissolved in methanol at 0.3 ml / min, and 0.11 g (0.0015 mol) of ammonium acetate was dissolved in methanol at 0.26 ml / min. And flowed into the mixer through a syringe pump of a microreactor adjusted to 70 ° C.

The solution passed through the microreactor was collected, and the precipitated byproduct of the reaction mixture was removed from the solution by filtration and concentrated under reduced pressure (1 atm, 60 DEG C, 1 hour) to obtain the target compound.

Yield: 0.2 g, yield: 88%, residual halide: 9 ppm.

Example  4: 1-Butyl-3- Methylimidazolium  Acetate

1.9 g (0.0068 mol) of 1-butyl-3-methylimidazolium triflomethanesulfonate was dissolved in methanol at 0.1 ml / min, and 0.52 g (0.0068 mol) of ammonium acetate was dissolved in methanol at 0.07 ml / min. And flowed into the mixer through a syringe pump of a microreactor adjusted to 70 ° C.

The solution passed through the microreactor was collected, and the precipitated byproduct of the reaction mixture was removed from the solution by filtration and concentrated under reduced pressure (1 atm, 60 DEG C, 1 hour) to obtain the target compound.

Yield: 1.2 g, yield: 88%, residual halide: 5 ppm.

Claims (7)

In the method for producing a high purity, ionic liquid having a carboxylic acid as an anion having a halide residual content of less than 20 ppm,
With a cation-providing intermediate ionic liquid of 1,3-dialkylimidazolium methylsulfate or 1,3-dialkylimidazolium trichloromethanesulfonate
Reacting, in a microreactor, with one anion-providing acetate compound selected from the group consisting of ammonium acetate, potassium acetate, and sodium acetate,
The flow rate flowing to the microreactor of the cation-providing intermediate ionic liquid is 0.01 ~ 2.0ml / min, the flow rate to the microreactor of the anion-providing acetate compound is 0.01 ~ 2.0ml / min,
And wherein the ionic liquid having carboxylic acid as an anion is 1,3-dialkylimidazolium acetate. delete The method of claim 1, further comprising separately depressurizing the reacted ionic liquid including the microreactor. The method of claim 1, wherein the amount of cation-providing intermediate ionic liquid is 0.0005 to 1.0 mole and the amount of anion-providing acetate compound is 0.0005 to 1.0 mole. delete The method of claim 1, wherein the reaction temperature is 0 ~ 100 ℃.
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