CN1328283C - Method of producing ammonium glyphosate - Google Patents

Abstract

The invention discloses a method for producing glyphosate ammonium salt. The method for producing ammonium glyphosate acid provided by the present invention is to use solid glyphosate acid and ammonia water as raw materials, use solid glyphosate acid as a stationary phase, and use ammonia water as a mobile phase to make the ammonia water flow through the solid glyphosate The phosphonic acid reacts together, so that the water in the mobile phase takes away the water-soluble reaction product ammonium glyphosate in time, and continuously obtains high-purity, high-activity ammonium glyphosate. The method for producing glyphosate ammonium salt of the present invention has the following advantages: 1) the product glyphosate ammonium salt has high purity; 2) the reaction efficiency is high; 3) the product glyphosate ammonium salt has high stability and activity; 4) The production process is simple, the equipment investment is small, and the product cost is low; 5) the production method of the present invention can be used in industrial large-scale continuous production; 6) the pollution is small and the energy consumption is low.

Description

A kind of method of producing glyphosate ammonium salt

technical field

The invention relates to a method for producing ammonium glyphosate.

Background technique

Glyphosate (chemical name: N-phosphonomethylglycine, whose structural formula is shown in formula I) has the advantages of high efficiency, low toxicity and no residue in the soil as a herbicide, and has become the world's largest sales and fastest growing herbicide. Fast killing herbicide. However, due to the low solubility of glyphosate in water, only 1.2 grams of glyphosate acid can be dissolved per 100 grams of water at 25°C. The general solution is to make it into salt-soluble powder, emulsion or water. Compared with glyphosate emulsion or water, glyphosate salt soluble powder products have the advantages of long validity period, low transportation and storage costs and convenient use. Glyphosate salts mainly include sodium salt, potassium salt and ammonium salt. Sodium salt is more hygroscopic than ammonium salt, and the production cost of potassium salt is high. Ammonium salt mainly contains methyl ammonium glyphosate (its structural formula is as shown in formula II), isopropyl ammonium glyphosate (its structural formula is as shown in formula III) and glyphosate ammonium salt (its structural formula is as shown in formula shown in IV). Since the decomposition product of ammonium glyphosate is ammonia that can be absorbed by plants, it has the advantages of low toxicity and environmental friendliness, while the decomposition products of ammonium glyphosate and ammonium glyphosate are highly toxic, respectively. And carcinogenic methylamine and isopropylamine, so ammonium glyphosate is more widely used.

At present, many patents have been related to the synthesis method of ammonium glyphosate acid from glyphosate acid. There are mainly two types of patents on the synthesis technology of ammonium glyphosate acid synthesized from glyphosate acid. The first type of patent discloses the preparation of ammonium glyphosate acid by reacting glyphosate acid with anhydrous ammonia. Gas-solid reaction method, related patents are CN1068008; IL118576; KR257283; ZA9604774; AU704518; HU9802088; Taking the patent CN1068008 as an example, the disadvantage of this gas-solid reaction method is that the solid product deposited on the reactor wall will affect the timely removal of the reaction heat; improper control of the ammonia gas addition rate will easily form fouling at the entrance. In addition, the solid ammonium salt formed on the surface of the glyphosate acid solid will hinder the reaction of the glyphosate acid inside the solid with anhydrous ammonia. Therefore, it is necessary to install solid products capable of continuously scraping off the precipitated solid product on the wall of the reactor, strictly control the addition rate of ammonia gas and make the particle size of the raw material glyphosate acid as small as possible. The second type of patented technology is to use ammonia solution and glyphosate acid to react to synthesize ammonium glyphosate. Related patents include CN1192743; CN1365254; CA2444608; EP1381278; US2002173423; ; HU9802333; NZ307310; CA2221298; AU694877; EP0845000; Taking CN1192743 as an example, this patent reacts with glyphosate acid and 29% ammonia water. In order to control the water content in the reaction system, it is necessary to regularly sample and analyze the water content. Water; In order to reduce the oxidation of glyphosate acid by hot air, it is also necessary to add antioxidant sodium sulfite in the reaction process. Obviously, the disadvantages of this production process are relatively complicated and high energy consumption. In addition, on November 8, 1999, Zhejiang Xin'an Chemical Group Co., Ltd. applied for the method of preparing ammonium glyphosate acid by feeding liquid ammonia into the autoclave to react with glyphosate acid (patent application number 99119971.5, publication number CN1260349) . The reaction is an exothermic reaction. Obviously, the timely removal of the reaction heat, the huge investment in ammonia gas recovery equipment and the high-pressure reaction and the potential safety hazards make this technology difficult to use in large-scale industrial production. On August 31, 2000, the company applied for a method for preparing ammonium glyphosate by reacting ammonia and glyphosate acid in an organic solvent (methanol, ethanol, petroleum ether, toluene, xylene or cycloalkane) (patent Application number 00125934.2, publication number CN1340508A). Obviously, the addition of these low-boiling, flammable or toxic organic solvents in the reaction system will not only greatly increase the production cost of the product, but also bring unsafe factors such as pollution and fire. On September 5, 2002, Zhejiang Xin'an Chemical Group Co., Ltd. applied for a patented technology of first reacting glyphosate acid, water and ammonia, and then adding organic solvents such as methanol, ethanol or methylal (patent application number 02141788.1 ), similar patent also has WO2004022570. Obviously, this type of technology will still greatly increase the production cost of the product, and will also bring disadvantages such as unsafe factors such as pollution and fire. CN1394482 patent application discloses reacting the former drug of glyphosate with ammonia, and adding natural raw material auxiliary agent into salt to prepare the method for glyphosate ammonium salt, but the addition of natural raw material auxiliary agent will not only increase the production cost, but also make the Product purification steps are added.

Like most organic reactions, the reaction of glyphosate acid and ammonia is also a kind of equilibrium reaction, and above-mentioned method all adopts the method that improves raw material ammonia concentration to promote reaction to carry out towards the direction of generating glyphosate ammonium salt, along with the reaction Carry out, the concentration of glyphosate acid and ammonia all reduces, and reaction rate reduces; And still have some glyphosate acid and ammonia not to react fully after reaction finishes, and reaction efficiency is low. For example, in the first type of patent, the method of anhydrous ammonia (high concentration pure ammonia) is adopted to promote The method that reaction carries out towards the direction of generating glyphosate ammonium salt; or, feed liquid ammonia (high-concentration pure ammonia) and glyphosate acid reaction and prepare the method for glyphosate ammonium salt in the autoclave (patent application number 00125934.2, and the publication number is CN1340508); in the second type of patented technology, the method etc. that react with larger ammoniacal liquor (29% ammoniacal liquor) and glyphosate acid with concentration.

Contents of the invention

The purpose of the present invention is to provide a kind of efficient continuous, the method for producing glyphosate ammonium salt with simple technique.

The method for producing ammonium glyphosate acid provided by the present invention is to use solid glyphosate acid and ammonia water as raw materials, use solid glyphosate acid as a stationary phase, and use ammonia water as a mobile phase to make the ammonia water flow through the solid glyphosate Phosphonic acid and react to obtain ammonium glyphosate.

In order to facilitate storage and transportation, the obtained ammonium glyphosate can also be prepared as a solid ammonium glyphosate through steps such as dehydration and crystallization.

In order to improve reaction efficiency and prevent the high-temperature oxidation of glyphosate acid, and make the reaction system temperature maintain below 60 ℃, the volume percentage concentration of described ammonia should be between 5-20%, it flows through the solid glyphosate acid The time or the contact time with solid glyphosate acid should be controlled between 10 minutes and 1.5 hours, preferably between 40 minutes and 70 minutes, and the ammonia water with high concentration should have a slower flow rate as much as possible. When the solid glyphosate acid decreases, it can be added at any time, so that the filling height of glyphosate acid in the reaction tower is high enough to ensure that the contact time between ammonia water and glyphosate acid is long enough to make all the ammonia in the mobile phase All the outlets can be reacted, and the synthesis reaction can be carried out continuously.

The method that the present invention produces glyphosate ammonium salt has following advantage: 1) product glyphosate ammonium salt purity is high: when the flowing ammonia water that the present invention adopts contacts the solid glyphosate acid that is fixed in reaction tower, promptly React to generate water-soluble ammonium glyphosate, and the ammonium glyphosate is dissolved in the water of the reaction system and is taken away by water; when the ammonia flows to the bottom of the reaction tower, all the ammonia in the ammonia has been The reaction with glyphosate acid is complete, and what flows out from the lower end of the reaction tower is basically a high-purity ammonium glyphosate solution; besides ammonia water and glyphosate acid, no other materials that can affect the purity of the product are introduced into the reaction raw materials; 2 ) high reaction efficiency: although the concentration of ammonia in the mobile phase of the present invention gradually decreases with the progress of the reaction in the process of flowing, the large water-soluble ammonium glyphosate can be taken away by water in time, so when grass When the filling height of glycyphosphonic acid in the reaction tower is large enough or when the contact time of ammonia and glyphosate acid in the mobile phase is long enough (10 minutes to 1.5 hours), the ammonia molecules in the system are all in the whole reaction tower. It has been reacting with high-concentration solid glyphosate acid, and the reaction is relatively complete; 3) The ammonium salt of glyphosate acid has high stability and activity: glyphosate acid has a solubility of 1.2 grams per 100 grams of water at 25°C. The only impurity with a content of about 1% in the obtained ammonium glyphosate product is glyphosate acid, and the herbicidal active ingredient of the ammonium glyphosate product is glyphosate acid, making the active ingredient of the product of the present invention High, reaching 92%; 4) The production process is simple, the equipment investment is small, and the product cost is low: the reaction tower used in the present invention is simple in structure, does not need devices such as high pressure, stirring, and the reaction product does not need post-processing steps such as complicated separation, adopts existing There are conventional distillation towers, crystallization towers and other equipment to obtain high-purity solid products; 5) the production method of the present invention can be used for industrial large-scale continuous production; 6) little pollution and low energy consumption: in the reaction process The raw material ammonia can all react with glyphosate acid to form ammonium glyphosate. The water separated by distillation does not contain ammonia and can be directly used for dilution of commercially available concentrated ammonia water. The entire production process can achieve zero emissions.

Description of drawings

Fig. 1 is the process flow chart of continuous production of glyphosate ammonium salt

Detailed ways

Embodiment 1, production glyphosate ammonium salt

The technological process for continuous production of ammonium glyphosate is shown in Figure 1, in which 1 is a reaction tower; 2 is a distillation tower; 3 is a crystallization tower. Reaction tower 1 bottom is provided with sieve plate 4 and sieve plate 5, is used for fixing solid glyphosate acid and intercepts the solid glyphosate acid that may run off; Its top also has the feeding port 6 of solid glyphosate acid, is used for feeding Replenish glyphosate acid in the reaction tower 1; Ammonia enters and sprays on the solid glyphosate acid from the top of the reaction tower 1, and flows through the solid glyphosate acid. The effluent from the lower end of the reaction tower 1 is an aqueous ammonium glyphosate solution. This ammonium glyphosate aqueous solution can be taken out by the one-way valve 7 below the reaction tower 1, also can flow continuously in the distillation tower 2, steams most of moisture of the ammonium glyphosate aqueous solution according to the conventional distillation method , become a concentrated solution of ammonium glyphosate; then the concentrated solution flows continuously into the crystallization tower 3 for crystallization, and a solid product of ammonium glyphosate with a purity of up to 98.8% can be obtained.

Be that the solid glyphosate acid of 1.5 meters is filled in the reaction tower 1 that height is 1.8 meters and diameter is 15 centimetres, then add the ammoniacal liquor that volume percent concentration is 5% with the amount of 8.8 milliliters/second from above, when grass When the glyphosate acid solids are reduced to 1.2 meters, add glyphosate acid solids to 1.5 meters in time. At this time, the time for the ammonia water to flow through the solid glyphosate acid or the contact time between the ammonia water and the solid glyphosate acid is 40-50 minutes, and the temperature in the reaction tower 1 can be maintained at 30-50° C. The effluent enters the distillation tower 2 and the crystallization tower 3 to carry out distillation and crystallization according to a conventional method, and obtain a solid product of ammonium glyphosate with a purity of 98.8%.

Embodiment 2, production glyphosate ammonium salt

The production process is the same as in Example 1. Be 1.8 meters in height, be that in the reaction tower 1 of 15 centimetres, fill in height and be the solid glyphosate acid of 1.5 meters, then add the ammoniacal liquor that concentration is 20% with the amount of 6.3 milliliters/second from above, when glyphosate When the acid solids are reduced to 1.2 meters, add glyphosate acid solids to 1.5 meters in time. At this time, the time for the ammonia water to flow through the solid glyphosate acid is 56-70 minutes, and the temperature in the reaction tower 1 can be automatically maintained at 45-60° C. The effluent enters the distillation tower 2 and the crystallization tower 3 to carry out distillation and crystallization according to a conventional method, and obtain a solid product of ammonium glyphosate with a purity of 98.8%.

Claims (5)

1. A method for producing ammonium glyphosate acid, using solid glyphosate acid and ammonia as raw materials, characterized in that: the solid glyphosate acid fixed in the reaction tower is the stationary phase, and the ammonia is the flowing Phase, make ammonia flow through solid glyphosate acid and react to obtain ammonium glyphosate. 2. The method according to claim 1, characterized in that: the volume percent concentration of said ammonia water is 5-20%. 3. The method according to claim 1 or 2, characterized in that: the obtained reaction product ammonium glyphosate can also undergo dehydration and crystallization steps to obtain high-purity, high-activity ammonium glyphosate solid product. 4. The method according to claim 1 or 2, characterized in that the time for the ammonia water to flow through the solid glyphosate acid or the contact time between the ammonia water and the solid glyphosate acid is 10 minutes to 1.5 hours. 5. The method according to claim 4, characterized in that the contact time is 40 minutes to 70 minutes.

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