New technology for preparating N-phosphono methyl glycine

Abstract

A process for synthesizing the glyphosate from the alkali metal salt of glycine includes such steps as acidifying with inorganic acid to obtain glycine and inorganic salt, concentrating, drying to obtain the mixture of glycine and salt, adding formaldehyde, alkyl phosphite, tetraamine as catalyst and unitary alcohol as solvent, and reaction to synthesize glyphosate as herbicide while separate out inorganic salt insoluble in the system.

Description

1. Technical field [0001] The invention relates to a preparation method of the herbicide N-phosphonomethylglycine (glyphosate) using alkyl phosphite as the main raw material. 2. Background technology [0002] The chemical name of glyphosate acid is N-phosphonomethylglycine (PMG for short), and its molecular formula is: It is a high-efficiency broad-spectrum herbicide. Because of its good systemic conductivity, it is very effective in the control of a variety of deep-rooted weeds. In recent years, the sales volume has gradually increased. With the glyphosate-resistant transgenic With the gradual promotion of crops, its application scope has been further expanded, and it has become the herbicide with the largest sales and fastest growth rate in the world. In 2002, the global sales of glyphosate reached 3 billion US dollars, accounting for 10% of the total sales of pesticides. . [0003] There are two main production processes for glyphosate acid that are now industrialized....

AI Technical Summary

Problems solved by technology

[0007] The prior art of the dialkyl phosphate route requires that its main raw material, glycine, has a higher quality. "The Production and Development Trend of Glycine" ("China Petroleum and Chemical Industry Analysis Report", No. 6, 2002, page 13) discloses the existing glycine The production process (chloroacetic acid ammonolysis method) has affected the quality of glyphosate acid due to the low quality of the product

The problem now is that the refining cost of glycine is very high: the ammonolysis method of chloroacetic acid needs a large amount of alcohol to separate glycine and by-product ammonium chloride, and the recovery of alcohol needs to consume a lot of energy, which leads to an increase in cost; catalytic dehydrogenation from monoethanolamine And the glycine alkali metal salt obtained by hydrocyanic acid method is more difficult to obtain higher-purity glycine. The electrodialysis process disclosed in "Ion Membrane Glycine New Technology" ("Henan Chemical Industry" 2001.1P19) is limited by the membrane. The concentration is low, and the refining cost is high due to the 4-9% escape rate of glycine

Therefore, although monoethanolamine and hydrocyanic acid can be obtained in the form of by-products, thus having lower raw material costs, they have not yet been industrialized in my country due to the high cost of refining.

[0008] Therefore, the glyphosate product quality of the dialkyl phosphate method is good, but the cost of the main raw material glycine is relatively high, which is an unresolved problem in the prior art.

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