NMP lateral extraction method

Abstract

An NMP lateral extraction method comprises the following steps: 1, neutralizing: neutralizing a raw material to adjust the pH value of the raw material to 9; 2, separating in a first rectifying tower:introducing the neutralized raw material into the first rectifying tower, and separating water, light components and impurities azeotropic with water from the raw material in the first rectifying tower; and 3, separating in a second rectifying tower: introducing the separated raw material obtained in the first rectifying tower into the second rectifying tower, arranging an extraction pipeline atone side of the second rectifying tower, connecting a condenser to one side of the extraction pipeline, arranging a reflux pipeline at the top of the second rectifying tower, separating the raw material by the second rectifying tower, performing total reflux through the top reflux pipeline, intermittently extracting water through the extraction pipeline at one side and the condenser, and obtainingan NMP product at the top of the second rectifying tower. The method has the advantages of realization of intermittent extraction of a small amount of water, and stable production control, allows theproduct quality to meet the NMP content of 99.8% or above, and reduces the water content of the recycled NMP to 100 ppm or below.

Description

technical field [0001] The invention belongs to the technical field of organic solvent recovery and treatment, and in particular relates to a side line extraction method of NMP. Background technique [0002] N-methylpyrrolidone, Chinese alias: NMP; 1-methyl-2-pyrrolidone; N-methyl-2-pyrrolidone. Colorless transparent oily liquid with slight amine odor. Low volatility, good thermal and chemical stability, can volatilize with water vapor. Hygroscopic. Sensitive to light. It is easily soluble in water, ethanol, ether, acetone, ethyl acetate, chloroform and benzene, and can dissolve most organic and inorganic compounds, polar gases, natural and synthetic polymer compounds. N-methylpyrrolidone is widely used in industries such as lithium batteries, medicine, pesticides, pigments, cleaning agents, and insulating materials. [0003] In the prior art, rectification separation and technical methods are usually used for the recovery and utilization of NMP, and the raw materials a...

AI Technical Summary

Problems solved by technology

[0004] However, in the actual operation process, due to the bubbles generated in the tower after the raw materials are neutralized, the control of the composition at the top of the tower is unstable, which affects the product quality, and high-quality products with a content of more than 99.8% and a moisture content of less than 200ppm cannot be obtained.