A method for producing glyphosate base

Abstract

The application discloses a production method of glyphosate mother drug, (1) through the air or oxygen oxidation of the aqueous solution of glyphosate under the action of a catalyst, glyphosate is obtained; (2) the original mother liquor is separated, the filter cake is washed with water, and the washing liquid is combined into the mother liquor; (3) the mother liquor is concentrated and separated by a membrane to obtain concentrated aqueous glyphosate solution; (4) the concentrated aqueous glyphosate solution obtained in the step (3) is combined into the filter cake, then an organic base or an inorganic base is added, a reaction is carried out to obtain an aqueous glyphosate salt solution, a catalyst is filtered and recycled to the step (1) glyphosate oxidation, and the filtrate is concentrated; (5) the aqueous glyphosate salt solution is concentrated through MVR evaporation to obtain the mother drug with a concentration of 35%-46%. The application effectively reduces the glyphosate original powder taking-out process, reduces production steps, improves intrinsic safety, and reduces energy consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to a production method of glyphosate mother drug. BACKGROUND

[0002] Glyphosate is a highly efficient and broad-spectrum herbicide with the characteristics of broad-spectrum, low toxicity and no residue. Glyphosate is mainly used in the field of transgenic crops. In recent years, due to the large-area planting of transgenic glyphosate-resistant crops such as soybeans and corn, the global demand for glyphosate has increased, and glyphosate has become the most influential and widely used herbicide variety in the world. Glyphosate raw drug is widely used by being processed into various types of granules and water agents. With the withdrawal of 10% glyphosate water agent and the continuous improvement of environmental protection requirements, it is necessary to improve the production process of glyphosate; at the same time, China has a large capacity of glyphosate production, and there are many industry manufacturers. In order to realize the competitiveness of the industry, it is necessary to reduce the production operation cost. SUMMARY

[0003] The purpose of the present application is to provide a production method of 35%-46% glyphosate mother drug which reduces the glyphosate raw powder taking-out process, reduces the production steps and reduces the production operation cost by 35%-46%. These 35%-46% glyphosate mother drugs can exactly meet the preparation conditions of various water agents.

[0004] The technical solution of the present application is:

[0005] A production method of 35%-46% glyphosate mother drug, characterized by comprising the following steps:

[0006] (1) Put glyphosate and catalyst into water to obtain a mixture containing 8%-25% glyphosate, and oxidize the mixture by air or oxygen to obtain glyphosate;

[0007] (2) After the reaction is completed, the original mother liquor is separated by cooling and filtering, the filter cake is washed with water, and the washing liquid is combined into the mother liquor;

[0008] (3) The mother liquor is separated by membrane concentration to obtain a concentrated glyphosate aqueous solution;

[0009] (4) The concentrated glyphosate aqueous solution obtained in step (3) is combined with the filter cake, then an organic base or an inorganic base is added, and a corresponding glyphosate salt aqueous solution is obtained by reaction, the catalyst is filtered and reused in step (1) for glyphosate oxidation, and the filtrate is concentrated;

[0010] (5) The glyphosate salt aqueous solution is concentrated by MVR evaporation to obtain 35%-46% (calculated as glyphosate acid) concentration of glyphosate mother drug.

[0011] Step (3) also yields wastewater containing formaldehyde and formic acid impurities after membrane separation. This wastewater is then sent to an MVR distillation unit. The vapor phase at the top of the distillation column is cooled to obtain a 2-3% formaldehyde aqueous solution, which reacts with ammonia to obtain a hexamethylenetetramine aqueous solution. The hexamethylenetetramine aqueous solution is then concentrated using a membrane to obtain a pre-concentrated hexamethylenetetramine. The pre-concentrated hexamethylenetetramine is then concentrated in an evaporation unit, cooled to crystallize, centrifuged, and dried to obtain hexamethylenetetramine with a content greater than 98%.

[0012] The glyphosate content in the mother liquor obtained in step (2) is about 1%; the glyphosate content in the concentrated glyphosate aqueous solution obtained in step (3) is 5%.

[0013] The organic or inorganic base is ammonia, isopropylamine, potassium hydroxide or sodium hydroxide, monoethanolamine, or dimethylamine.

[0014] The advantages of this invention are: it reduces the glyphosate technical powder extraction process, thus reducing production steps, labor, and the use of steam and refrigeration, thereby improving intrinsic safety; the mother liquor concentration process uses membrane separation instead of evaporation, reducing steam consumption and energy consumption; the evaporation process uses MVR continuous evaporation devices, fully utilizing the energy of secondary steam, significantly reducing steam consumption, energy consumption, and operating costs, and enhancing the product's market competitiveness; wastewater is distilled, and formaldehyde, which is difficult to biochemically treat, is fully recovered and utilized for the synthesis of hexamethylenetetramine as a byproduct, generating certain economic benefits; the distillation residue, after being rendered harmless, can be directly introduced into the biochemical system. This invention belongs to the category of safe, energy-saving, and environmentally friendly technologies. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] Figure 1 This is a process flow diagram of one embodiment of the present invention. Implementation

[0017] A method for producing 35%~46% glyphosate technical grade involves adding 9000 kg of deionized water, 3000 kg of 98% glyphosate, and 500 kg of catalyst to a reactor, starting stirring, heating to 80°C, and introducing compressed air or oxygen for oxidation. After the reaction is complete, the mixture is cooled and filtered. The filter cake is washed with 2000 kg of deionized water, filtered again, and the wash water is combined with the mother liquor. Another 2000 kg of deionized water is added to the filter cake, stirring is started, and the mixture is stored. The resulting 11000 kg mother liquor (containing 0.98% glyphosate, 1.15% formaldehyde, 0.6% formic acid, and other impurities) is concentrated using a membrane to obtain 2113.7 kg of a 5.1% glyphosate aqueous solution, which is pumped to the filter cake solution. 1100 kg of 20% ammonia water is slowly added to the filter cake solution, and the reaction continues until the solution becomes clear. The solution is then filtered to obtain 8113.7 kg of the final product. A 25.6% glyphosate ammonium salt aqueous solution was filtered to obtain 600 kg of wet catalyst, which was then reused for diglyphosate oxidation. The 25.6% glyphosate aqueous solution was concentrated in an MVR continuous evaporation system to obtain 5917.7 kg of a 35.1% (based on glyphosate acid) glyphosate ammonium salt aqueous solution, which can be used to prepare a 30% glyphosate ammonium salt solution. 8886.3 kg of wastewater containing 1.4% formaldehyde, 0.7% formic acid, and some other impurities, obtained from membrane concentration separation, was sent to an MVR distillation unit. The vapor phase at the top of the distillation column was cooled to obtain 4100 kg of a 2.92% formaldehyde aqueous solution, which reacted with ammonia to obtain a hexamethylenetetramine aqueous solution. The distillation column bottom contained 4786.3 kg of residual liquid containing 0.098% formaldehyde and 1.3% formic acid, which could be fed into the biochemical system. The hexamethylenetetramine aqueous solution was concentrated by membrane treatment to obtain 769.5 kg of 12.1% hexamethylenetetramine. The aqueous solution of hexamethylenetetramine was concentrated in an evaporator, then cooled to crystallize, centrifuged, and dried to obtain 93.6 kg of hexamethylenetetramine with a purity of 98.5%.

Claims

1. A method for producing 35% to 46% glyphosate technical, characterized in that: It comprises the following steps: ​ (1) Put the glyphosate acid and catalyst into water to obtain a mixture containing 8-25% glyphosate acid, which is oxidized by air or oxygen to obtain glyphosate; (2) After the oxidation reaction is completed, cooling is performed, and the original mother liquor is obtained through solid-liquid separation; the filter cake is washed with water, and the washing liquid is combined into the mother liquor; (3) The mother liquor is concentrated and separated by a membrane to obtain a concentrated glyphosate aqueous solution; (4) The concentrated glyphosate aqueous solution obtained in step (3) is combined with the filter cake, then an organic base or an inorganic base is added, and a corresponding glyphosate salt aqueous solution is obtained through reaction; the catalyst is filtered and reused in step (1) for glyphosate acid oxidation, and the filtrate is concentrated; (5) The glyphosate salt aqueous solution is concentrated by MVR evaporation to obtain a 35-46% glyphosate mother liquor.

2. The method for producing 35% to 46% glyphosate technical according to claim 1, characterized in that: Step (3) also obtains wastewater containing formaldehyde and formic acid impurities through membrane separation, which is sent to an MVR rectification device; through rectification, 2-3% formaldehyde aqueous solution is obtained at the top of the vapor phase, which is reacted with ammonia water to obtain an urotropine aqueous solution; the urotropine aqueous solution is concentrated by membrane concentration to obtain a preliminary concentrated urotropine; the preliminary concentrated urotropine is concentrated by an evaporation device, and then cooled and crystallized, centrifuged, and dried to obtain urotropine with a content of more than 98%.

3. The method for producing 35% to 46% glyphosate technical according to claim 1, characterized in that: The mother liquor obtained in step (2) contains about 1% glyphosate; the concentrated glyphosate aqueous solution obtained in step (3) contains about 5% glyphosate.

4. The method for producing a 35% to 46% glyphosate technical according to claim 1, 2 or 3, characterized in that: The organic base or inorganic base is ammonia water, isopropylamine, potassium hydroxide, sodium hydroxide, monoethanolamine, or dimethylamine.

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