Process for separating acetonitrile-water azeotrope system by adopting ionic liquid extraction distillation

Abstract

The invention discloses a process for separating an acetonitrile-water azeotrope system by adopting ionic liquid extraction distillation. According to the process, an ionic liquid azeotropic agent is adopted, so that the relative volatility of acetonitrile in the acetonitrile-water system can be enhanced, the solvent ratio can be reduced, and the concentration of acetonitrile in a vapor phase is increased along with the increment of the mass percent of ionic liquid; ionic liquid cations are imidazolium cations or pyridine cations, and ionic liquid anions are halogen anions, acetic acid anions, bistrifluoromethylsulfimide anions, hexafluorophosphoric acid anions, dibutyl phosphate anions or trifluoromethanesulfonic acid anions. When the mass percent of the ionic liquid is 15%-60%, an acetonitrile-water azeotropy point can be disappeared. When the mass ratio of the ionic liquid to acetonitrile-water binary azeotrope is 1 : 4, the extraction distillation can be well carried out to obtain more than 99% of acetonitrile, and the ionic liquid is environment-friendly and recyclable.

Description

technical field [0001] The invention relates to the field of extractive distillation, in particular to an ionic liquid for separating acetonitrile-water azeotrope by extractive distillation and an extractive distillation method. Background technique [0002] Acetonitrile is a commonly used industrial solvent, which can be used in the manufacture of vitamin B1 and other drugs and spices, and can also be used as an extractant for fatty acids, alcohol denaturant, butadiene extractant and solvent for acrylonitrile synthetic fibers. The produced acetonitrile can only be widely used when its purity reaches more than 99%. [0003] Since the acetonitrile-water system is a completely miscible binary azeotrope system, the azeotrope temperature is 76°C at 1 atmospheric pressure, and the acetonitrile content in the azeotropic composition is 85wt%, so it cannot be separated by conventional rectification methods . Simple rectification can only obtain acetonitrile with a content of less ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a kind of ionic liquid and extraction method that can be used for extracting and rectifying acetonitrile-water azeotrope system to solve the problem that the common separation method of acetonitrile-water binary azeotrope system in the current te

Images