A method for recovering methyl tert-butyl ether in pharmaceutical process waste liquid by extractive distillation-adsorption coupling process

Abstract

The invention belongs to the field of solvent recovery, and in particular relates to a method for recovering methyl tertiary butyl ether from waste liquid in a pharmaceutical process by an extractive distillation-adsorption coupling process. Using water as the extractant and the waste liquid of the pharmaceutical process respectively enter the extractive rectification tower according to a certain solvent ratio, the crude product containing n-butane and methyl tert-butyl ether is separated at the top of the extractive rectification tower, and the material in the tower still enters the extractant. The recovery tower recovers the extractant, and the extractant recovered from the column is cooled and returned to the extractive rectification tower for recycling; after the material at the top of the extractive rectification tower is stratified by the phase separator, the lower water phase is returned to the extractive rectification tower, The upper oil phase enters the adsorption dehydration system to obtain the n-butane-containing methyl tert-butyl ether material, which enters the n-butane separation tower, and the tower still obtains the methyl tert-butyl ether, which can be recycled as a pharmaceutical solvent. The invention uses the existing component water in the waste liquid as the extractant, effectively avoids introducing other components to affect the recycling use of methyl tertiary butyl ether, and is an efficient and energy-saving separation process.

Description

technical field [0001] The invention belongs to the field of solvent recovery, and in particular relates to a method for recovering methyl tert-butyl ether in pharmaceutical process waste liquid through an extractive distillation-adsorption coupling process. Background technique [0002] 4-Chloro-2-(trifluoroacetyl)aniline hydrochloride hydrate, referred to as E2, molecular formula: C 8 h 5 CIF 3 NO·HCl·H 2 O, molecular weight: 278, CAS number: 173676-59-0, is a white or light yellow crystalline powder, main use: as a key intermediate for the synthesis of anti-AIDS drug efavirenz. Intermediate E2 is obtained by using p-chloroaniline as the starting material, first performing condensation reaction with pivaloyl chloride, then undergoing acylation reaction and hydrolysis reaction, and finally refined. During the condensation reaction and acylation reaction, it needs to be carried out in a large amount of methyl tert-butyl ether solvent. The reaction process is accompanied ...

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Problems solved by technology

[0003] For the above-mentioned waste liquid produced, the recovery of the solvent methyl tert-butyl ether is a very difficult problem, this is due to the presence of multiple groups of binary azeotropes in the system under normal pressure, the binary azeotrope of ethanol and methyl tert-butyl ether The ethanol content in the meta-azeotropic composition is 7.7wt%, and the azeotropic temperature is 57.9°C; the ethanol content in the binary azeotropic composition of ethanol and water is 95.6wt%, and the azeotropic temperature is 78.2°C; The content of tert-butanol in the meta-azeotropic composition is 87.5wt%, and the azeotropic temperature is 80.3℃; the content of methyl tert-butyl ether in the binary azeotropic composition of methyl tert-butyl ether and water is 94.1wt%, and the azeotropic The temperature is 55.9°C; the n-butane content in the binary azeotropic composition of n-butane and water is 98.7wt%, and the azeotropic temperature is -1.72°C, so it is difficult to remove water, ethanol and tert-butanol in the mixture by ordinary rectification , needs to pass special rectification, such as extractive rectification or azeotropic rectification, but through extractive rectification or azeotropic rectification, it is necessary to introduce a third component as an extractant or entrainer, resulting in the circulation of methyl tert-butyl ether It is inevitable to introduce other impurities during use, which will affect the quality of intermediate E2

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