Preparation method of methyl-glycine diacetate tri-sodium

A technology of methylglycine diacetic acid trisodium salt and hydroxyacetonitrile, which is applied to the preparation of organic compounds, cyanide reaction preparation, chemical instruments and methods, etc., can solve the problems of heavy environmental pollution, large energy consumption, and high production costs. Achieve the effects of low content of toxic by-products, lower energy consumption, and equipment investment

Active Publication Date: 2013-03-27
CHONGQING UNISPLENDOUR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] It can be seen that the above-mentioned methods for preparing MGDA·3Na all need to use high-purity hydrocyanic acid or metal cyanide solution as raw materials, and additional high-purity reaction raw material refining equipment needs to be configured, the production cost is high, the energy consumption is large, and the refining process will generate waste water , heavy environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A preparation method of trisodium methylglycine diacetate, which comprises the following steps successively:

[0029] First put 1622g (37%, mass percentage concentration, the same below) formaldehyde solution into a reactor with a reflux condenser, adjust the pH value to 7.5, and then pass hydrocyanic acid into the reactor at 25°C 6800g (8%) crude hydrocyanic acid gas from the synthesis tower, keep the reactor temperature at 25°C and pH value of 7.5 during the process, and obtain 2280g of hydroxyacetonitrile solution. This hydroxyacetonitrile solution was preheated to 75°C, and 170g of ammonia gas was heated to 60°C at the same time, and then the two were mixed rapidly and passed through a tubular reactor within 2.0 minutes at a reaction temperature of 90°C to obtain iminodi Acetonitrile solution 2355g (39.1%); adjust pH = 2.0 with sulfuric acid, pass 3300g (8%) crude hydrogen cyanide gas from hydrogen cyanide synthesis tower under the condition of keeping the system te...

Embodiment 2

[0031] A preparation method of trisodium methylglycine diacetate, which comprises the following steps successively:

[0032]First put 3500g (37%, mass percentage concentration, the same below) formaldehyde solution into a reactor with a reflux condenser, adjust the pH value to 6.0, and then pass hydrocyanic acid into the reactor at 30°C 11900g (9.8%) of crude hydrocyanic acid gas from the synthesis tower, in the process, 4780g of hydroxyacetonitrile solution was obtained. This hydroxyacetonitrile solution is preheated to 80°C, and 367g of ammonia gas is heated to 70°C simultaneously, and then the two are mixed rapidly and passed through a tubular reactor within 3.0 minutes, the reaction temperature is 80°C, and the iminobis Acetonitrile solution 5330g (37.2%); adjust pH = 3.0 with sulfuric acid, and pass 5950g (9.8%) crude hydrogen cyanide gas from hydrogen cyanide synthesis tower under the condition of keeping the system temperature at 25 ° C, while 970g (98% ) Acetaldehyde ...

Embodiment 3

[0034] A preparation method of trisodium methylglycine diacetate, which comprises the following steps successively:

[0035] First put 2192g (36.5%, mass percentage concentration, the same below) formaldehyde solution into a reactor with a reflux condenser, adjust the pH value to 7.0, and then pass hydrocyanic acid into the reactor at 0°C 14600g (5%) crude hydrocyanic acid gas from the synthesis tower, in the process, 2943g of hydroxyacetonitrile solution was obtained. This hydroxyacetonitrile solution was preheated to 40°C, and 227g of ammonia gas was heated to 40°C at the same time, then the two were mixed rapidly and passed through a tubular reactor within 1.0 minute, and the reaction temperature was 100°C to obtain iminodi Acetonitrile solution 3305g (36.1%); Regulate pH=1.5 with sulfuric acid, keep the system temperature at 10 ℃ and pass into 7000g (5%) crude hydrogen cyanide gas from hydrogen cyanide synthesis tower, simultaneously 580g (98% ) acetaldehyde was added dro...

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Abstract

The invention relates to a preparation method of methyl-glycine diacetate tri-sodium, successively comprising the following steps of: preparation of hydroxy acetonitrile solution, preparation of iminodiacetonitrile solution, preparation of methyl-flycine nitrile diacetonitrile crystal, preparation of methyl-glycine diacetate tri-sodium (MGDA-3Na) and preparation of solid product MGDA-3Na. In the method, the yield of methyl-flycine nitrile diacetonitrile crystal is higher than 92%, the total yield of MGDA-3Na can reach more than 86%, the content of NTA (nitrilotriacetic acid) is less than 0.08%; and the equipment investment and energy consumption in the hydrocyanic acid refining process are saved on the premise that high yield and low toxic side product content are met, and the hydrocyanic acid refining process is not required, so that the production cost is reduced and the environment pollution is reduced.

Description

[0001] technical field [0002] The invention relates to a commonly used compounding agent, especially methylglycine diacetic acid, in particular to a preparation method of methylglycine diacetic acid trisodium salt. Background technique [0003] Compared with commonly used complexing agents such as aminopolyphosphates, polycarboxylates or aminopolycarboxylates (e.g. ethylenediaminetetraacetic acid, EDTA), methylglycine diacetic acid (MGDA) is non-toxic and readily biodegradable Advantages, can be used in the production of cleaners, polishes and adhesives for hardened substrates. Its synthesis method and application are respectively described in US5817864, US5849950, CN101171226A and CN100580072C, CN1977036B, CN101029208A. Among them, methylglycine diacetic acid trisodium salt (MGDA·3Na) is widely used in production. [0004] In the prior art, the common synthetic method of methylglycine diacetic acid trisodium salt can be divided into two big classes: the one is to carry...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C229/16C07C227/26
Inventor 王友仁李艳韩丹杨凤杨宗美
Owner CHONGQING UNISPLENDOUR CHEM
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