Method for preparing N-Phosphonomethyl iminodiacetic acid through hydrolyzing iminodiacetonitrile

Abstract

The invention discloses a method for preparing N-Phosphonomethyl iminodiacetic acid through hydrolyzing iminodiacetonitrile, which comprises the following steps: hydrolyzing and deaminating the iminodiacetonitrile by using lime aqueous solution to obtain solution with the iminodiacetonitrile, acidizing the solution by using hydrochloric acid aqueous solution and sulfuric acid aqueous solution, filtering calcium desulfurization, decoloring filtrate by using active carbon; removing sulfate ions by using barium salt, removing metal ions through an ion-exchange resin column, condensing to obtain solution with iminodiacetic acid salt, reacting with phosphorous acid and formaldehyde under the catalysis of inorganic acid, condensing, crystallizing and filtering reaction solution, respectively collecting filter cakes and filtrate, finally obtaining N-Phosphonomethyl iminodiacetic acid after the filter cakes are dried, and recycling the filtrate. The invention has the advantages of short process flow, high product recovery rate, low production cost, easy comprehensive utilization of byproducts, less three-waste discharge, low environmental pollution as well as favorable economic and environment benefits.

Description

technical field

[0001] The invention relates to a preparation method of diglyphosate, in particular to a method for preparing diglyphosate by hydrolysis of iminodiacetonitrile. Background technique

[0002] Diglyphosate (N-Phosphonomethyl Iminodiacetic Acid, PMIDA) is an important intermediate of glyphosate, the herbicide with the largest production and sales volume in the world, and has broad market prospects.

[0003] The traditional preparation method of diglyphosate is the iminodiacetic acid (IDA) method developed by U.S. Monsanto Company, that is, with hydrocyanic acid or diethanolamine as starting raw material, first prepare high-purity iminodiacetic acid solid, and then combine with phosphorous acid Or phosphorus trichloride, formaldehyde carry out condensation reaction to prepare bisglyphosate. Among them, the preparation of high-purity iminodiacetic acid solid needs to acidify the intermediate iminodiacetic acid disodium salt with sulfuric acid, convert it into imi...