Three major production processes of glyphosate
Glyphosate (Glyphosate), also known as Roundup, Peasant Music, etc., is a post- emergence non-selective high-efficiency broad-spectrum herbicide with broad-spectrum, low-toxicity and no residue. Glyphosate is mainly used in the field of genetically modified crops.
Three major production processes of glyphosate
Iminodiacetic acid method
1) Preparation of iminodiacetic acid Chloroacetic acid was reacted with aqueous ammonia in the presence of calcium hydroxide, acidified, and neutralized with sodium hydroxide to obtain a yield of 85%. Or using cyanogenic acid as raw material, and reacting with formaldehyde and ammonia, the yield is 90%.
2) Preparation of glyphosate The reaction of iminodiacetic acid with formaldehyde and phosphorous acid in the presence of sulfuric acid to obtain glyphosate was obtained in a yield of 90%.
3) Synthesis of glyphosate Glyphosate is mixed with water, and an excess of hydrogen peroxide is heated in the presence of equimolar sulfuric acid to obtain glyphosate in a yield of 90% to 95%.
2. Chloromethylphosphonic acid method
1) Preparation of chloromethylphosphonic acid The reaction is carried out with phosphorus trichloride and paraformaldehyde at 200-250 ° C (corresponding pressure of 2.5-3.0 MPa) for 3-5 hours to obtain chloromethylphosphonic dichloride. The literature reports that the ratio is phosphorus trichloride: polyformaldehyde is 1.2-1.5:1 mole, the yield is 67% in the absence of catalyst, and the yield of Lewis acid can be increased to 80%-89%. Hydrolysis gives chloromethylphosphonic acid.
2) Synthesis of glyphosate equimolar chloromethylphosphonic acid and glycine in a sodium hydroxide aqueous solution (pH > 10), refluxing for 10-20 hours, and then acidified glyphosate with hydrochloric acid. If acidified to pH = 4, it is a monosodium salt, and pH = 8.5 is a disodium salt.
3. The dialkyl phosphite method is prepared by addition, condensation and hydrolysis of glycine, dialkyl phosphite and paraformaldehyde. The purity of the product is 95%, the total yield is 80%, and the cost is low. .
China's pesticide network Xiaobian warm reminder of the use of glyphosate: glyphosate is a herbicide herbicide, avoid contaminating crops when applying, so as not to cause phytotoxicity. Glyphosate is acidic and should be used as much as possible in storage and use.
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