A kind of preparation method of high-purity imidazole acetate ionic liquid

Abstract

The invention belongs to the technical field of ionic liquid synthesis, and in particular relates to a preparation method of a high-purity imidazole acetate ionic liquid, in which a 1-alkyl-3-methylimidazole halogenated product is reacted with lithium perchlorate to obtain a high-purity Pure 1-alkyl-3-methylimidazolium perchlorate ionic liquid intermediate; the intermediate is then subjected to metathesis reaction with potassium acetate or ammonium acetate to obtain 1-alkyl-3-methylimidazolium acetate ion Liquid, raw materials are cheap and easy to obtain, raw materials or intermediate by-products have no heavy metals or other pollution, the reaction is thorough, the reaction yield is higher than 90.0%, the product purity is higher than 99.0%, the halogen residue in the product is less than 5ppm, and the K ion or ammonium in the product Root content is less than 200ppm.

Description

technical field [0001] The invention belongs to the field of ionic liquid synthesis, in particular to a method for preparing a class of high-purity ionic liquids in which the cation is imidazole (ring) and the anion is acetate. Background technique [0002] Ionic liquid is an emerging functional material with many advantages such as extremely low vapor pressure, high electrical conductivity, stable chemical properties, and flowable physical form. Hot spots with development prospects. In addition to the above advantages, ionic liquids also have a wide variety of characteristics. Both anionic and cationic 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. The concept of green is very suitable for the current concept of environmental protection. At pr...

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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

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