Method for finely preparing iminodiacetic acid

Abstract

The invention discloses a method for finely preparing iminodiacetic acid, and the method comprises the following steps: hydrolysis, heat preservation, heating removal of ammonia, material transferring, hydrochloric acid neutralization, concentration, cooling, filtration, crystallization and recrystallization, and the like. The advantages are as follows: activated carbon and a concentrated liquid are added in a neutralization section and a recrystallization section, so that byproducts in mother liquor are easy to accumulate, the heating process of each section is segmented, so that the reaction is mild, material rushing in the iminodiacetic acid preparation process is effectively avoided, the byproducts in the mother liquor are easy to handle, and after crystallization treatment, the byproducts can also be applied.

Description

technical field [0001] The invention relates to iminodiacetic acid, in particular to a refined preparation method of iminodiacetic acid. Background technique [0002] Iminodiacetic acid, also known as diglycine and aminodiacetic acid, is an important fine chemical product with strong complexation and can form chelates with various metal ions. It is used in pesticides, dyes, chemicals, water It is widely used in processing, medicine, functional polymers, electronics, etc. It is an important raw material for pesticides, pharmaceuticals, rubber, surfactants, complexing agents, food additives, electroplating industry, synthetic metal surface treatment agents and ion exchange resins, etc. and intermediates. [0003] There are mainly four methods for producing iminodiacetic acid in the prior art, namely, iminodiacetonitrile alkali hydrolysis method, iminodiacetonitrile acid hydrolysis method, chloroacetic acid method and diethanolamine oxidation method. Among them, the chloroace...

AI Technical Summary

Problems solved by technology

Among them, the chloroacetic acid method is to react chloroacetic acid with ammonia water and calcium hydroxide, acidify with hydrochloric acid to generate iminodiacetic acid hydrochloride, stand for crystallization, suction filter, pickle, dissolve it in hot water, add Sodium hydroxide solution to generate iminodiacetic acid, crystallization, separation, and drying to obtain the product. This method is mature, but has the disadvantages of long process, low product purity, high cost, and serious "three wastes"

The use of hydrolysis is a relatively commonly used method in the prior art, but in the prior art, the process control process of the hydrolysis method in the production process is relatively simple, especially the treatment of by-products in the process adopts a direct separation method, As a result, the mother liquor after the end is difficult to handle

Images