Method for treating glyphosate mother liquor

Abstract

The invention provides a method for treating glyphosate mother liquor. The method comprises the following steps: introducing dimethylamine gas into the bottom of a gas-liquid countercurrent packed tower, absorbing the dimethylamine gas through taking the glyphosate mother liquor as an absorbent and collecting alkaline liquid at the bottom of the tower; introducing the liquid into a rectifying tower for rectification to obtain triethylamine and tower bottom liquid; dehydrating the tower bottom liquid at reduced pressure, adding hydrochloric acid to adjust the pH value of the tower bottom liquid to strong acidity, cooling, crystallizing and filtering to obtain glyphosate; and further distilling the filtered filtrate at reduced pressure to obtain dimethylamine hydrochloride. Compared with the prior art, the method provided by the invention has the advantages that the dimethylamine gas is utilized to replace other liquid alkalies to recover the catalyst triethylamine in the glyphosate mother liquor, the obtained glyphosate and the dimethylamine hydrochloride are useful chemical products and no waste is produced, so that the method is high in recovery rate, high in recovery product quality, friendly to environment and economic; in the meanwhile, the gas-liquid countercurrent packed tower is adopted in the method, so that the method is more safe in reaction and is beneficial to the continuous and large scale treatment of the glyphosate mother liquor.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and in particular relates to a treatment method for glyphosate mother liquor. Background technique [0002] Glyphosate is a high-efficiency, broad-spectrum, systemic, and conductive organophosphorus chemical herbicide. It has the advantages of wide application, good weeding effect, low price, and good environmental compatibility. It is currently the most widely used herbicide in the world. One of the most widely used and produced chemical herbicides. It was developed by Monsanto in the United States in the early 1970s and registered in the United States in 1974. The production of glyphosate in my country started in the 1980s and was synthesized by the dimethyl phosphite method (also known as the glycine method) in 1986. The process of glyphosate has been industrialized in China. The raw materials of this method are easy to obtain, the process conditions are stable, the yield is high, and s...

AI Technical Summary

Problems solved by technology

[0005] However, the process for treating mother liquor has the following problems: (1) The total amount of mother liquor after treatment increases (by adding 30% sodium hydroxide solution, a large amount of water is brought in), which increases the energy consumption during concentration and increases the cost of sewage treatment; (2) The use of glyphosate water solution prepared by concentrated mother liquor (containing a large amount of sodium chloride) makes the content of sodium chloride in the spit too high, which will easily cause poor soil dispersion, sticky soil, and become sodium-alkaline soil, which will cause damage to crops. Harm and eventually lead to crop yield reduction and quality decline, so the Ministry of Agriculture has issued document No. 1158, prohibiting the use and sale of this water agent; (3) The herbicidal efficacy of this glyphosate sodium salt solution is both in terms of quick-acting and thorough Both are less effective than other glyphosate salt preparations