Method for recovering solvent from ammoximation reaction liquid

Abstract

The invention provides a method for recovering a solvent from an ammoximation reaction liquid. The method comprises the following steps: feeding a reaction liquid containing ammonia, the solvent, cyclohexanone oxime, water and cyclohexanone into a primary distillation tower (a), and evaporating out partial solvent containing ammonia and water from a tower top; and feeding materials in a tower kettle into a secondary distillation tower (b), and carrying out pressure distillation by utilizing exterior heat source so as to obtain high-temperature vapor containing the solvent from the tower top and obtain a material containing cyclohexanone oxime, water and cyclohexanone from the tower kettle, wherein the high-temperature vapor containing the solvent serves as the distillation heat source for the primary distillation tower (a). By using the method, the energy consumption for the solvent recovery can be reduced.

Description

technical field [0001] The invention relates to a method for recovering a solvent from an ammoximation reaction solution. More specifically, it relates to the separation of the ammoximation reaction solution and the preparation of cyclohexanone oxime. Cyclohexanone oxime is mainly used in the production of caprolactam and is an important intermediate in the production of caprolactam. Background technique [0002] At present, cyclohexanone oxime is mainly produced in industry by the oximation method of hydroxylamine salt, such as hydroxylamine phosphate method (HPO), hydroxylamine sulfate method (HSO) and the like. These methods have many intermediate steps, complex processes, use a large amount of corrosive and heavily polluted raw materials, and cause great harm to the environment. [0003] The ammoximation reaction of cyclohexanone, ammonia and hydrogen peroxide using titanium silicon molecular sieve as a catalyst is a new process for preparing cyclohexanone oxime. This ...

AI Technical Summary

Problems solved by technology

These methods have many intermediate steps, complex processes, and use a large amount of corrosive and heavily polluting raw materials, causing great harm to the environment.

[0003] The ammoximation reaction of cyclohexanone, ammonia and hydrogen peroxide using titanium silicon molecular sieve as a catalyst is a new process for preparing cyclohexanone oxime. This method has the characteristics of simple process and low pollution, but the ammoximation Use a large amount of solvents in the reaction process, and solvent is generally selected from alcohols, and wherein suitable is tert-butanol and Virahol, as in the disclosed method of U.S. Patent USP4794198 and USP5227525, needs 2~5 times of cyclohexanone Tert-butanol is used as solvent, and isopropanol is used as solvent in the disclosed method of CN1556098. Recycling and utilization of these solvents from the reaction product usually adopts the method of atmospheric distillation, which needs to consume a large amount of energy, which makes the production cost of cyclohexanone oxime increase

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