Glufosinate purifying technology

Abstract

The invention provides a glufosinate purifying technology including the following steps: (1) adding glufosinate hydrochloride to alcohol R1OH, adding R2NH2 for ammoniation, adjusting the pH to 7.0-14.0, cooling and filtering, removing a solvent from a filtrate to obtain glufosinate ammonium salt and a small amount of organic impurities; (2) dissolving the glufosinate ammonium salt obtained by the steps (1) in an appropriate amount of water, leading in CO2 for neutralizing to the pH of 2.0-5.0, adding a proper amount of alcohol R3OH for precipitation of glufosinate acid, centrifugally filtrating to obtain the glufosinate acid which contains a small amount of ammonium hydrogen carbonate or organic amine carbonates; (3) heating for drying a glufosinate acid filtering cake obtained by the step (2) for decomposition and volatilization of the ammonium hydrogen carbonate or organic amine carbonates to obtain high purity glufosinate acid. The glufosinate purifying technology is simple in steps, the obtained glufosinate is low in inorganic salt content and high in purity, and compared with a traditional technology using epoxy ethane and epoxy propane, the purifying technology using carbon dioxide for separation of glufosinate hydrochloride and HCl is more economical, and high in safety, and has a higher industrialization prospect.

Description

【Technical field】 [0001] The invention belongs to chemical purification methods, in particular to a high-purity glufosinate-ammonium purification process. 【Background technique】 [0002] Glufosinate-ammonium is a contact herbicide with high efficiency, low toxicity, low residue, and safety. It has been widely used in orchards, vineyards, palm orchards, ornamental shrubs, and non-arable land to control annual and perennial dicotyledonous herbicides. and grass weeds, and used in economic crops such as potato fields, forests and alpine pastures. Glufosinate-ammonium, the English name is Glufosinate, the chemical name is 4-[hydroxyl (methyl)phosphono]-DL-homoalanine ammonium or 4-[hydroxyl (methyl)phosphono]-DL-homoalanine , whose structural formula is: [0003] [0004] Glufosinate-ammonium is a herbicide developed by Bayer of Germany, and its invention has been published in multiple patents. For example, US patents US4168983, US4264532, US4264532, US4499027, US4599207, e...

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Problems solved by technology

[0008] The process route is long, and repeated alcohol washing with excessive amounts of alcohols results in large alcohol consumption and low yield; in the process of removing organic impurities by alcohol washing, it is caused by the high solubility of glufosinate-ammonium hydrochloride in alcohols. The yield is low; in the process of removing hydrogen chloride, flammable and explosive ethylene oxide needs to be introduced, and the operation risk factor is large

Although the content of glufosinate-ammonium phosphonic acid obtained by this purification process is relatively high, because of its long process route, many raw materials and large consumption, the total purification yield of this purification process is low, which is only 45% (based on glufosinate ammonium) through experimental verification. phosphonic acid meter), and the higher cost

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