Purifying method of ionic liquid

An ionic liquid and purification method technology, applied in the field of purification of ionic liquids, can solve the problems of poor thermal stability of ionic liquids, consumption of large energy and time, loss of ionic liquids, etc., so as to shorten purification time, save purification time, and reduce energy consumption. Effect

Inactive Publication Date: 2012-05-09
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But there are many shortcomings in this method: first, this method cannot completely remove the impurities in the ionic liquid, and cannot obtain a high-purity ionic liquid. If you want to obtain a higher purity, you need to prolong the purification time, which greatly reduces the purification time. efficiency; secondly, due to the high viscosity of ionic liquids and the slow diffusion process of volatile impurities, the purification process consumes a lot of energy and time; finally, some ionic liquids have poor thermal stability, so it may cause ionic liquids to The thermal decomposition of this method limits the use of this method. If the purification temperature is lowered, the purification time will be further extended. Therefore, for ionic liquids with poor thermal stability, the purification efficiency of this method is too low
Even for ionic liquids with good thermal stability, through such long-term heating and vacuuming, the degradation of ionic liquids will be caused, resulting in the loss of ionic liquids
It can be seen that the traditional method has many defects in the process of removing impurities in the ionic liquid, which makes this method unable to further improve the purity of the ionic liquid.
The impurities remaining in the ionic liquid, such as water and organic solvents, will have adverse effects on the application of the ionic liquid. They not only reduce the purity of the ionic liquid, but also change the physical and chemical properties of the ionic liquid.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] This example shows that the method of the present invention can use nitrogen to purify 1-butyl-3-methylimidazolium tetrafluoroboric acid containing moisture, and can achieve good results.

[0029] Add 5kg of 1-butyl-3-methylimidazolium tetrafluoroboric acid with a water content of 5.6% into the spray tower, control the temperature in the tower to 70 degrees Celsius, and adjust the total gas flow to 10m 3 / h, the pressure is 0.1MPa, the ionic liquid is sprayed down from the top of the tower through the circulation pump, the gas enters from the bottom of the tower, and is discharged from the top of the tower. After purging for 1 hour by countercurrent contact method, the water content in the ionic liquid can be reduced to 0.05%.

Embodiment 2

[0031] This example shows that the method of the present invention can use nitrogen to purify 1-butyl-3-methylimidazolium tetrafluoroboric acid containing moisture, which is better than the traditional high-temperature and low-pressure distillation method.

[0032] The method of the present invention: 0.5 kg of 1-butyl-3-methylimidazolium tetrafluoroboric acid with a moisture content of 5.6% is added to the purification kettle, which has 4 inlet pipes at the bottom and an outlet pipe at the top One is connected with a pressure gauge and a temperature control device, and the gas inlet and outlet are controlled by valves. After heating the temperature in the purification kettle to 70 degrees Celsius, open the outlet pipe, open the four inlet pipes, and adjust the total flow rate to 0.5m 3 / h, the pressure inside the kettle is 0.1MPa, and after purging for 1 hour by bubbling method, the water mass content in the ionic liquid can be reduced to 0.08%.

[0033] High-temperature and...

Embodiment 3

[0036] This example shows that the method of the present invention can use purified air to purify 1-butyl-3-methylimidazolium tetrafluoroboric acid containing ethanol, and can achieve good results.

[0037]Add 0.5 kg of 1-butyl-3-methylimidazolium tetrafluoroboric acid with an ethanol content of 5.0% into the purification kettle, which has four inlet pipes at the bottom and one outlet pipe at the top. There are pressure gauges and temperature control devices, and the gas inlet and outlet are controlled by valves. After heating the temperature in the purification kettle to 70 degrees Celsius, open the outlet pipe, open the four inlet pipes, and adjust the total flow rate to 0.5m 3 / h, the pressure inside the kettle is 0.1MPa, and after purging for 1 hour by bubbling method, the mass content of ethanol in the ionic liquid can be reduced to 0.01%.

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PUM

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Abstract

The invention provides a purifying method of ionic liquid. The purifying method comprises a step that: the ionic liquid is purged by using inert gas, such that volatile impurities in the ionic liquid are removed. With the method, volatile substances in synthesized or recovered ionic liquid containing volatile impurities can be removed in a relatively short time, such that the purification of the ionic liquid is realized. Compared to traditional methods, with the method provided by the invention, the purification time can be shortened, the energy consumption during the purification period can be reduced, and the degradation of the ionic liquid can be avoided.

Description

technical field [0001] The invention relates to a method for purifying an ionic liquid. Specifically, the invention relates to a method for using gas to sweep the ionic liquid to remove volatile impurities in the ionic liquid. Background technique [0002] Ionic liquid is a kind of organic molten salt, which is composed of organic cations and inorganic or organic anions, and is liquid at room temperature or near room temperature. It evolved from traditional high-temperature molten salts, but compared to conventional ionic compounds, ionic liquids are liquid in a wide temperature range around room temperature. Ionic liquids have many excellent properties: a wide range of liquid temperature, from below or close to room temperature to above 300 °C, good thermal and chemical stability; almost no vapor pressure; adjustable structure and controllable properties of ionic liquids ;Exhibits good solubility for many organic and inorganic substances, and can dissolve a variety of gase...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D1/14
Inventor 吴卫泽任树行
Owner BEIJING UNIV OF CHEM TECH
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