Method for synthesis of N-(phosphonomethyl) iminodiacetic acid

Abstract

The invention discloses a method for synthesis of N-(phosphonomethyl) iminodiacetic acid. The method comprises steps of: introducing IDA-2Na through a bipolar membrane system to acquire iminodiacetic acid- sodium salt; reacting the obtained IDA-Na with acid for an acidizing reaction to obtain IDA solid as a PMIDA production source a, and separating IDA solid from reactants to obtain a mother liquor; entering the mother liquid into a secondary bipolar membrane system for secondary recovery of 3-15%NaOH, and in an acid region generating IDA-containing acidic solution as a PMIDA production source b or as a replacement of acid used in the acidizing reaction; mixing the PMIDA production source a and the production source b to form a production source C, and blending the production source C into suitable reaction molar ratio (IDA:H3PO3:HCl = 1:1.05-1.2:0.3-1.5) for a PMIDA synthesis reaction; and reacting the production source C with formaldehyde to prepare PMIDA. The invention overcomes the defects of the prior art, is simple, easy to operate, and is a typical clean production technique.

Description

technical field [0001] The invention relates to a method for synthesizing N-(phosphonomethyl)iminodiacetic acid. Background technique [0002] The production technology of N-(phosphonomethyl) iminodiacetic acid (diglyphosate is called for short PMIDA) in the prior art, main method is to use iminodiacetic acid disodium salt (IDA-2Na) as starting material its acquisition There are two methods: one is to use iminodiacetonitrile to deaminate with alkali and the other is to use diethanolamine alkali to dehydrogenate it. A considerable amount of acid is used in its production and a large amount of sodium chloride is associated. ZL200410014898.4 can solve many production processes However, there are still deficiencies such as low resource utilization. [0003] The content of the reaction steps in the existing PMIDA production process: [0004] Step 1, the preparation process of iminodiacetic acid disodium salt NH(CH2COONa)2 (abbreviation: IDA-2Na), there are mainly two methods ...

AI Technical Summary

Problems solved by technology

[0014] 1. A large amount of alkali is consumed in the production process (generally 32% liquid NaOH is used);

[0015] 2. Use and consume a large amount of acid (generally 30% hydrochloric acid) in the production process;

[0016] 3. A large amount of low-value NaCl is produced by-product and will cause different degrees of entrainment with IDA or PMIDA, resulting in low product quality or its loss. Second, desalination, evaporation and desalination are difficult, and the amount of high-salt wastewater formed during production is large and the cost of biochemical treatment is high.