Preparing method of high-purity imidazole acetate ionic liquid

A technology of pure imidazole acetate and methylimidazole acetate, which is applied in the field of preparation of high-purity ionic liquids, can solve the problems of harsh reaction conditions, high raw material alkoxide prices, and expensive raw materials, and achieve moderate reaction speed, The effect of high product purity and cheap raw materials

Active Publication Date: 2019-10-01
SHANDONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method not only has a huge number of by-products and seriously pollutes the environment, but also has a large amount of lead ions remaining in the form of complexation in the product.
[0009] Disclosed in CN1914181A are two preparation methods of imidazole acetate ionic liquid, the preparation process of the two methods is relatively complicated, and the raw material alkoxide used is expensive, flammable, and the reactants are extremely sensitive to water, the cost is high, and it is not conducive to control , it is also easy to introduce impurities such as sulfur and barium
But the conversion rate of this reaction is low (up to 91.5%), and a lot of residues of 1-substituent imidazole raw materials remain in the product
And in the synthetic process, the C of No. 2 position of 1-substituent imidazole will react with dimethyl carbonate to generate some carbonyl by-products, resulting in impure product
[0014] All in all, the current preparation methods of acetic acid ionic liquids more or less have the following problems: the raw materials contain heavy metals or other pollution; the raw materials are expensive; the reaction is not complete or prone to disproportionation; the reaction process is slow; Halogen and metal ions remain more

Method used

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  • Preparing method of high-purity imidazole acetate ionic liquid
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Examples

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Effect test

Embodiment 1

[0043] Preparation of 1-ethyl-3-methylimidazolium acetate ionic liquid:

[0044] Dissolve 1.0mol of 1-ethyl-3-methylimidazolium chloride salt with 48g of water to obtain solution A, dissolve 1.2mol of lithium perchlorate with 254g of water to obtain solution B; mix solution A with solution B, Add 575g of dichloromethane, mechanically stir and react for 12 hours; separate the liquid, separate the water phase as waste liquid, recycle, wash the organic phase with 260g of pure water each time, wash 5 times, use AgNO 3 No precipitation was detected in the solution; the organic phase was rotary evaporated in vacuum at 80°C to obtain 193g of 1-ethyl-3-methylimidazole perchlorate ionic liquid intermediate, with a yield of 91.9%; 579g of ethanol was added, and under vigorous stirring, Slowly add a total of 90.1g of potassium acetate in 4 batches. During the addition process, solids dissolve and precipitate continuously, and continue to stir for 24 hours; stop stirring, freeze to -15°C ...

Embodiment 2

[0046] Preparation of 1-butyl-3-methylimidazolium acetate ionic liquid:

[0047] Dissolve 1.0mol of 1-butyl-3-methylimidazolium bromide with 58g of water to obtain solution A, dissolve 0.8mol of lithium perchlorate with 170g of water to obtain solution B; mix solution A with solution B, Add 531g of dichloromethane, mechanically stir and react for 12 hours; separate the liquid, wash the organic phase with 278g of pure water each time, wash 3 times, use AgNO 3 No precipitation was detected in the solution; the organic phase was vacuum rotary evaporated at 80°C to obtain 178.4g of the 1-butyl-3-methylimidazole perchlorate ionic liquid intermediate, with a yield of 93.7%; 446g of ethanol was added, and under vigorous stirring, Slowly add a total of 79.8g of potassium acetate in 4 batches. During the addition process, solids are continuously dissolved and precipitated. Continue to stir for 12 hours; stop stirring, freeze to -15°C for 36 hours, filter, and spin the filtrate at 80°C....

Embodiment 3

[0049] Preparation of 1-octyl-3-methylimidazolium acetate ionic liquid:

[0050] Dissolve 1.0 mol of 1-octyl-3-methylimidazolium chloride salt with 78 g of water to obtain solution A, dissolve 2.0 mol of lithium perchlorate with 426 g of water to obtain solution B; mix solution A with solution B, Add 841g of dichloromethane, mechanically stir and react for 12 hours; separate the liquid, separate the water phase as waste liquid, recycle, wash the organic phase with 256g of pure water each time, wash 3 times, use AgNO 3 The solution detects no precipitation; the organic phase is vacuum rotary evaporated at 80°C to obtain 193g of the 1-octyl-3-methylimidazole perchlorate ionic liquid intermediate, with a yield of 91.9%; add 965g of ethanol, stir vigorously, and divide Slowly add a total of 90.1g of potassium acetate in 4 batches. During the addition process, solids dissolve and precipitate continuously, and continue to stir for 48 hours; stop stirring, freeze to -15°C for 12 hour...

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Abstract

The invention belongs to the technical field of ionic liquid synthesis, and particularly relates to a preparing method of high-purity imidazole acetate ionic liquid. The method includes the steps of making a 1-alkyl-3-methylimidazole halogenated product react with lithium perchlorate to obtain a high-purity 1-alkyl-3-methylimidazole perchlorate ionic liquid intermediate, and then conducting replacement reaction on the intermediate and potassium acetate or ammonium acetate to obtain the 1-alkyl-3-methylimidazole acetate ionic liquid. The raw materials are low in price and easy to obtain, the raw materials or middle byproducts are free of heavy metals or other pollutions, reaction is thorough, the reaction yield is 90.0% or above, the product purity is 99.0% or above, the content of halogenresidues in the product is smaller than or equal to 5 ppm, and the content of K ions or ammonium radicals in the product is 200 ppm or below.

Description

technical field [0001] The invention belongs to the field of ionic liquid synthesis, and in particular relates to a preparation method of a class of high-purity ionic liquid whose cation is imidazole (ring) and anion is acetate. Background technique [0002] Ionic liquid is an emerging functional material, which has many advantages such as extremely low vapor pressure, high electrical conductivity, stable chemical properties, and flowable physical form. A hotspot with development prospects. In addition to the above advantages, ionic liquids also have a wide variety of characteristics. Both anion and cation structures can be molecularly grafted according to needs, so ionic liquids are a universal chemical material in the future; on the other hand, ionic liquids have the largest The advantage is that it is green and environmentally friendly, and there is no volatile loss during use. Its green concept is very suitable for the current concept of environmental protection. At pr...

Claims

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Application Information

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IPC IPC(8): C07D233/58
CPCC07D233/58
Inventor 陈辉李凯明王晓航林孟昌
Owner SHANDONG UNIV OF SCI & TECH
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