Method for ionic liquid extractive rectification and removal of acid and water simultaneously

Abstract

Belonging to the technical field of separation and purification, the invention relates to a method for ionic liquid extractive rectification and removal of acid and water simultaneously. The method includes the step of: sending an industrial material containing certain acid and water into an extractive rectification tower through a pipeline, and the operation conditions of the rectification tower include: a temperature of 20-100DEG C, a pressure of 1-5atm, a number of theoretical plates of 10-40, and a solvent ratio of 0.5-5. The industrial material has a water content of 0.1%-5% (mass fraction, the same below), an acid content of 0.1%-5%, a tower top material water content of less than 2000ppm, and an acid content of less than 2000ppm. The operation conditions of high temperature flash tank are: a temperature of 100-200DEG C and a pressure of 0.01-0.9atm, and the ionic liquid extracted from the bottom of the flash tank can be recycled. When the ionic liquid is employed for extractive rectification and removal of acid and water simultaneously, the acid content and water content of the final material can both reach the ppm level, and the acid in the material can be recovered through the flash tank.

Description

technical field [0001] The invention relates to a method for simultaneous deacidification and dehydration by ionic liquid extraction and rectification. The extractant can be a single ionic liquid or a mixed solution of two ionic liquids. The cations of the ionic liquids can be imidazoles, pyridines, quaternary ammonium salts, etc., and the anions can be bistrifluoromethanesulfonimide, tetrafluoroborate, Hexafluorophosphate, acetate, diethyl sulfate, etc. It belongs to the technical field of separation and purification. Background technique [0002] In industrial production, materials containing acid and water are often produced, which must be deacidified and dehydrated to prevent corrosion and blockage of pipes and equipment by acidic materials. In addition, when the acid in the material is used as a reactant in the system, it needs to be recovered and returned to the reaction system for further conversion. Taking various ester compounds as an example, in the production p...

AI Technical Summary

Problems solved by technology

In the prior art, there are the following problems: due to the water solubility of the acid, the acid carried in the crude ester enters the water layer when the crude ester is dehydrated, causing an increase in the consumption of raw material acid; It will also be lost with the water layer of the phase separator, resulting in acid loss; multiple rectification towers consume a lot of steam, increasing energy consumption; the entire process is complex and costly; a large amount of waste water is generated during alkali washing and water washing, causing environmental pollution

In addition, there are many other deacidification and dehydration methods reported in patents, such as physical dehydration method: use thin film evaporator to evaporate water under high temperature and certain vacuum conditions, or use 3A / 4A molecular sieve adsorption column for dehydration; physical deacidification method, Molecular distillation is used to separate the acid at high temperature and a certain degree of vacuum; chemical deacidification method is used to deacidify through a basic anion exchange resin adsorption column, but these methods have large energy consumption, and the deacidification and dehydration medium is easily damaged. Problems such as difficult desorption process and low production capacity

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