Method for synthesizing glyphosate by one-pot method
By directly reacting N-hydroxymethylglycine with phosphorus trichloride in aqueous solution, the problems of unsatisfactory yield and complex process in the existing glyphosate production methods are solved, and efficient production of high-purity glyphosate is achieved , reduces production costs and solvent losses, improves production efficiency and environmental protection.
Patent Information
- Application Number
- CN202411299835.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2024-12-20
AI Technical Summary
The existing glyphosate production methods have problems such as unsatisfactory yields, complex processes, high solvent losses, high costs and difficult to deal with by-products.
Glyphosate is synthesized by one pot method. By reacting N-hydroxymethylglycine with phosphorus trichloride in aqueous solution, the pH value is controlled within the range of 4-6, and glyphosate is directly generated, avoiding intermediates and solvents. The use of the process simplifies the process.
High yields of high purity glyphosate (>90%) are achieved, production costs are reduced, process steps are simplified, solvent use and recycling needs are reduced, production efficiency and economic benefits are improved, and the process is more environmentally friendly and safe.
Smart Images
Figure CN119161382A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of chemical synthesis, and in particular to a method for synthesizing glyphosate in one pot. Background Art
[0002] Glyphosate (Glyphosate; N-(phosphonomethyl)glycine) is a broad-spectrum organophosphorus herbicide. The current mainstream glyphosate production method is mainly a production method using glycine and dimethyl phosphite as raw materials, which is a method of reacting dimethyl phosphite with formaldehyde, glycine, etc. to generate glyphosate dimethyl ester, and then hydrolyzing to obtain glyphosate. This method has the advantages of high efficiency and high purity, but the yield of this method is usually between 80% and 85%, and it needs to consume catalysts such as triethylamine, and involves the recovery of methanol solvent. The production system is relatively complex, and the atomic yield is not ideal. In addition, there is also a method of preparing IDA by hydrolyzing hydroxyacetonitrile and iminodiacetonitrile, and then adding formaldehyde to prepare diphosphine, and then oxidizing to obtain glyphosate, which is also widely used, but this method also has the problems of many reaction steps, long process flow, and unsatisfactory product yield.
[0003] Chinese invention patent application CN117069759A discloses a method for synthesizing glyphosate and its salt derivatives, comprising mixing N-hydroxymethylglycine or N-hydroxymethylglycine ester, an organic solvent and phosphorous acid and stirring them uniformly, heating the reaction system to above the boiling point of the organic solvent, dehydrating the evaporated condensate, and then refluxing the organic solvent into the reaction system to generate glyphosate. The method uses an organic solvent, which will cause solvent loss, and the recovery of the organic solvent requires energy consumption and is costly.
[0004] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention
[0005] To overcome the deficiencies of the prior art, the present invention provides a one-pot method for synthesizing glyphosate.
[0006] The present invention adopts the following technical solution:
[0007] A one-pot method for synthesizing glyphosate comprises the following steps:
[0008] (1) mixing material A and phosphorus trichloride to react to obtain a mixture containing glyphosate, wherein the material A contains N-hydroxymethylglycine salt, an acid binder and water, and during the reaction, the pH value of the reaction system is controlled to be not less than 4, and the reaction process is as follows: phosphorus trichloride is hydrolyzed into phosphorous acid and hydrochloric acid, phosphorous acid reacts with N-hydroxymethylglycine salt to generate glyphosate, and at the same time, cations in the N-hydroxymethylglycine salt and cations in the acid binder react with hydrochloric acid to generate corresponding hydrochloride;
[0009] (2) post-treating the mixture containing glyphosate obtained after the reaction in step (1) to obtain a glyphosate finished product.
[0010] Preferably, the reaction temperature of step (1) is 0-60°C.
[0011] Preferably, the reaction temperature of step (1) is 5-35°C.
[0012] Preferably, in step (1), the pH value of the reaction system is controlled within the range of 4-6.
[0013] Preferably, the acid binding agent is used to control the pH value of the reaction system to be not less than 4 during the reaction, and the acid binding agent is at least one of a soluble carbonate or a bicarbonate.
[0014] Preferably, in the material A, the mass fraction of sodium N-hydroxymethylglycinate is 1-30%.
[0015] Preferably, the N-hydroxymethylglycine salt in the material A is at least one of sodium N-hydroxymethylglycine, potassium N-hydroxymethylglycine, and ammonium N-hydroxymethylglycine.
[0016] Preferably, in the material A, the mass fraction of sodium N-hydroxymethylglycinate is 15-25%.
[0017] Preferably, the post-treatment in step (2) includes at least one of filtration, washing, dehydration, recrystallization and drying.
[0018] Preferably, the one-pot method refers to a kettle reaction, and the method comprises the following steps:
[0019] (1.1) placing an aqueous solution of N-hydroxymethylglycine salt into a reaction kettle, adding an acid binding agent and stirring until a milky white uniform suspension and a well-dispersed suspension are formed, as material A; preferably, the N-hydroxymethylglycine salt is sodium N-hydroxymethylglycine;
[0020] (1.2) adding phosphorus trichloride dropwise to the suspension, controlling the reaction temperature at 0-60° C., controlling the pH value of the reaction system at 4-6, and after the reaction is completed, cooling to room temperature, discharging the material, filtering, and obtaining a crude glyphosate;
[0021] (1.3) The crude glyphosate is washed with water, dehydrated and dried to obtain a finished glyphosate product.
[0022] Preferably, the one-pot process refers to a continuous flow reaction, and the method comprises the following steps:
[0023] (1-1) N-hydroxymethylglycine salt, an acid binding agent and water are fully stirred and mixed to form a uniformly mixed suspension as material A; preferably, the N-hydroxymethylglycine salt is sodium N-hydroxymethylglycine;
[0024] (1-2) controlling the feed temperature of the material A to be 25-50° C., the feed temperature of the phosphorus trichloride to be 0-15° C., and setting the reaction temperature of the continuous flow reactor to be 0-60° C., starting the continuous feeding of the material A and the phosphorus trichloride, respectively controlling the flow rates of the material A and the phosphorus trichloride through the feed pumps, ensuring that the molar amount of the N-hydroxymethylglycine salt in the material A and the molar amount of the phosphorus trichloride enter the mixer at an equal molar flow rate of 1:1, and after rapid mixing in the mixer, entering the continuous flow reactor for reaction, after the reaction is completed, collecting the reaction solution, filtering to obtain a crude glyphosate;
[0025] (1-3) The crude glyphosate is washed, dehydrated, dried and recrystallized to obtain a finished glyphosate product.
[0026] The present invention has the following advantages:
[0027] Compared with the existing production process using dimethyl phosphite as a raw material, the present invention does not introduce calcium salts, catalysts such as triethylamine, and the like, and does not require the synthesis of intermediates such as iminodiacetic acid and dimethyl phosphite, nor does it require the purchase of expensive raw materials such as dimethyl phosphite. It can directly use water-soluble N-hydroxymethylglycine salt and phosphorus trichloride in a one-pot synthesis to prepare high-purity glyphosate. The present invention does not produce byproducts such as methyl chloride that are difficult to handle, and has the advantages of fewer synthesis steps, shorter process, lower production cost, fewer product impurities, and higher product purity.
[0028] Compared with the production process of CN117069759A, the present invention does not use organic solvents, and no longer needs to purchase expensive raw materials such as phosphorous acid for feeding. Instead, it directly uses cheaper phosphorus trichloride as a raw material to synthesize glyphosate in an aqueous solution system in a one-pot process, which is lower in cost.
[0029] In summary, the advantages of the present invention are: higher yield, reduced solvent use cost (the use of organic solvents is not only expensive, but also inevitably leads to solvent loss, and the recovery of organic solvents requires energy consumption, and faces greater safety risks), and the use of cheaper and more readily available phosphorus trichloride instead of phosphorous acid / dimethyl phosphite, which has lower costs, higher product yields, and significant economic benefits. Specifically, the advantages of the present invention include:
[0030] 1. Use low-cost raw materials and fewer reaction steps to achieve high conversion rate (>90%) and high atomic yield;
[0031] 2. Easy to scale up mass production, realize full-continuous and fully automated production, and reduce labor costs;
[0032] 3. Improve the production efficiency of glyphosate and its salts and other derivative products, and significantly reduce production costs (by 30%-50%);
[0033] 4. Reduce or eliminate the discharge of three wastes, and make the production process green, environmentally friendly and safe;
[0034] 5. It is easy to realize large-scale production and reduce the equipment investment cost of large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Figure 1 The hydrogen nuclear magnetic spectra of glyphosate prepared in Examples 1 and 2 of the present invention are shown. DETAILED DESCRIPTION
[0036] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention. In the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other.
[0037] Unless otherwise specified, "%" herein refers to mass percentage "wt%"; "room temperature" or "normal temperature" herein refers to a temperature in the range of 15-40°C.
[0038] The specific embodiment of the present invention provides a one-pot method for synthesizing glyphosate, which comprises the following steps:
[0039] (1) mixing material A and phosphorus trichloride to react to obtain a mixture containing glyphosate, wherein the material A contains N-hydroxymethylglycine salt, an acid binder and water, and during the reaction, the pH value of the reaction system is controlled to be not less than 4, and the reaction process is as follows: phosphorus trichloride is hydrolyzed into phosphorous acid and hydrochloric acid, phosphorous acid reacts with N-hydroxymethylglycine salt to generate glyphosate, and at the same time, cations in the N-hydroxymethylglycine salt and cations in the acid binder react with hydrochloric acid to generate corresponding hydrochloride;
[0040] (2) post-treating the mixture containing glyphosate obtained after the reaction in step (1) to obtain a glyphosate finished product.
[0041] In a preferred embodiment, the reaction temperature of step (1) is 0-60°C, more preferably 5-35°C.
[0042] In a preferred embodiment, the pH value of the reaction system in step (1) is controlled within the range of 4-6.
[0043] In a preferred embodiment, the acid binding agent is used to control the pH value of the reaction system to be not less than 4 during the reaction process, and the acid binding agent is at least one of a soluble carbonate or a bicarbonate, for example, the acid binding agent is at least one of sodium carbonate and sodium bicarbonate. Soluble carbonate and / or bicarbonate as an acid binding agent can convert the hydrochloric acid generated by the reaction into hydrochloride, which is convenient for subsequent post-treatment, and it is more preferable to monitor the pH value of the reaction system in real time during the reaction process, and when the pH value is lower than 4, replenish the acid binding agent aqueous solution in time to maintain the pH value of the solution in the reaction process not lower than 4, and it is more preferable to keep the pH value of the reaction system at 4-6.
[0044] For example, when sodium bicarbonate is used as the acid binding agent and the N-hydroxymethylglycine salt in material A is sodium N-hydroxymethylglycine, the reaction equation can be expressed as follows:
[0045] C3H6NNaO3+PCl3+2NaHCO3=C3H8NO5P+2CO2+3NaCl; when sodium carbonate is used as the acid binding agent and the N-hydroxymethylglycine salt in material A is sodium N-hydroxymethylglycine, the reaction equation can be expressed as follows: C3H6NNaO3+PCl3+H2O+Na2CO3=C3H8NO5P+CO2+3NaCl.
[0046] In a preferred embodiment, in the material A, the mass fraction of sodium N-hydroxymethylglycinate is 1-30%, more preferably 15-25%.
[0047] In a preferred embodiment, the N-hydroxymethylglycine salt in the material A includes but is not limited to at least one of sodium N-hydroxymethylglycine, potassium N-hydroxymethylglycine, and ammonium N-hydroxymethylglycine.
[0048] In a preferred embodiment, the post-treatment in step (2) includes at least one of filtration, washing, dehydration, recrystallization and drying.
[0049] In a preferred embodiment, the one-pot method refers to a kettle reaction, and the method comprises the following steps:
[0050] (1.1) placing an aqueous solution of N-hydroxymethylglycine salt into a reaction kettle, adding an acid binding agent and stirring until a milky white uniform suspension and a well-dispersed suspension are formed, as material A; preferably, the N-hydroxymethylglycine salt is sodium N-hydroxymethylglycine;
[0051] (1.2) adding phosphorus trichloride dropwise to the suspension, controlling the reaction temperature at 0-60° C., controlling the pH value of the reaction system at 4-6, and after the reaction is completed, cooling to room temperature, discharging the material, filtering, and obtaining a crude glyphosate;
[0052] (1.3) The crude glyphosate is washed with water, dehydrated and dried to obtain a finished glyphosate product.
[0053] In a preferred embodiment, the one-pot process refers to a continuous flow reaction, and the method comprises the following steps:
[0054] (1-1) N-hydroxymethylglycine salt, an acid binding agent and water are fully stirred and mixed to form a uniformly mixed suspension as material A; preferably, the N-hydroxymethylglycine salt is sodium N-hydroxymethylglycine;
[0055] (1-2) controlling the feed temperature of the material A to be 25-50° C., the feed temperature of the phosphorus trichloride to be 0-15° C., and setting the reaction temperature of the continuous flow reactor to be 0-60° C., starting the continuous feeding of the material A and the phosphorus trichloride, respectively controlling the flow rates of the material A and the phosphorus trichloride through the feed pumps, ensuring that the molar amount of the N-hydroxymethylglycine salt in the material A and the molar amount of the phosphorus trichloride enter the mixer at an equal molar flow rate of 1:1, and after rapid mixing in the mixer, entering the continuous flow reactor for reaction, after the reaction is completed, collecting the reaction solution, filtering to obtain a crude glyphosate;
[0056] (1-3) The crude glyphosate is washed, dehydrated, dried and recrystallized to obtain a finished glyphosate product.
[0057] The "one-pot method" described in the present invention includes multiple implementation modes such as kettle reaction and continuous flow reaction, which can realize highly automated and continuous production. The specific embodiments of the present invention are further described below.
[0058] In the following embodiments, the acid binding agent is sodium bicarbonate, and the N-hydroxymethylglycine salt in material A is sodium N-hydroxymethylglycine. Sodium N-hydroxymethylglycine can be prepared by a known method, and the known method includes but is not limited to the autoclave and continuous flow synthesis methods mentioned in the Chinese invention patent "A continuous flow synthesis process of sodium N-hydroxymethylglycine" (Publication No. 113956171A).
[0059] Example 1, kettle synthesis of glyphosate:
[0060] (1) 381.2 g of solid powder of sodium N-hydroxymethylglycinate (purity> 99%) was accurately weighed and added into 1000 ml of purified water. After rapid stirring for 35 minutes, it was observed by naked eyes that the solid powder had dissolved to a clear and transparent state. Then 504.1 g of sodium bicarbonate was added and the mixture was stirred at a medium-high speed for 1-2 hours until a milky white uniform suspension and a well-dispersed suspension were formed, which was used as material A.
[0061] (2) Slowly add 520 g of phosphorus trichloride dropwise, paying close attention to changes in material temperature and pH. Ensure that the bubbles generated by the reaction can be released evenly (without flushing the material) before the addition is completed, and that the temperature of the reaction system is controlled below 50°C. Monitor the pH changes during the entire reaction process, and control the pH value of the reaction material solution to be no less than 4.0. If the pH value of the solution is found to be lower than 4.0, add sodium carbonate aqueous solution dropwise. After the pH value rises back to 6.0 and can remain stable, maintain stirring for 3 hours and stop heating. Allow the material to cool naturally for 2-4 hours, measure with a thermometer to determine that it has cooled to room temperature (or cooled to about 35°C), then discharge the material and filter with a suction flask to obtain a mixture containing about 1100 g of glyphosate and sodium chloride;
[0062] (3) The mixture obtained in the previous step is added to 2000 ml of pure water and stirred for 1-2 hours to allow the soluble part to fully dissolve, and filtered again to obtain about 500 g of glyphosate wet product;
[0063] (4) After the water in the glyphosate wet product is dried by centrifuge, it is washed 1-2 times with a small amount of purified water (about 15 ml each time), and after dehydration by centrifuge, it is dried again to obtain about 480 grams of glyphosate solid powder. In this example, the product yield is 94.6%.
[0064] Take samples for inspection and compare the infrared correlation (>95%) with the NMR spectrum (such as Figure 1 The H NMR spectrum of the sample is shown, confirming that it is basically consistent with the standard spectrum.
[0065] The test results are shown in Table 1 below.
[0066] Table 1:
[0067]
[0068] Example 2, continuous flow synthesis of glyphosate:
[0069] The continuous flow synthesis process includes the following steps:
[0070] (1) After uniformly mixing crystalline powders of sodium N-hydroxymethylglycinate (99%) and sodium bicarbonate (99.5%) at a molar ratio of 1:2, adding the mixture into purified water with a mass fraction of the mixture material: water of 1:1-1:2, stirring at room temperature for 2-4 hours, the resulting uniform mixed suspension is used as material A. In this example, the feed amounts are 127.1 g of sodium N-hydroxymethylglycinate, 168 g of sodium bicarbonate, and 420 ml of purified water;
[0071] (3) Phosphorus trichloride was used as material B. In this example, 137.5 g (87.35 ml) of phosphorus trichloride was used.
[0072] (4) The feed temperature of material A is controlled to be 25-50°C, the feed temperature of material B is controlled to be 0-15°C, and the reaction temperature of the continuous flow microreactor is set to 45°C. The continuous feeding of material A and material B is started. The flow rates of material A and material B are controlled by feed pumps (such as screw pumps or plunger pumps) respectively to ensure that the molar amount of sodium N-hydroxymethylglycinate in material A and the molar amount of phosphorus trichloride in material B enter the mixer at an equal molar flow rate of 1:1. After rapid mixing in the mixer, the material enters the continuous flow tubular reactor (a vertical tubular reactor is recommended, and the material enters the tubular reactor from the bottom and is discharged from the top). After internal heat exchange in the tubular reactor, the temperature of the reaction liquid is accurately controlled at 45°C, and the upper and lower amplitudes of the temperature change do not exceed 0.1°C. After a predetermined reaction residence time (15-30 minutes), the reaction liquid is collected from the discharge port of the continuous flow tubular reactor. The discharge port is provided with a gas-liquid separator to facilitate the escape of gases such as carbon dioxide.
[0073] Among them, the flow rate is adjusted by adjusting the pressure of the two-way feed pump to control the reaction time and feed ratio. In this example, the feed flow rate of material A is 6.396mL / min, the feed flow rate of material B is 1.0mL / min, and the pH of the discharged reaction liquid is 5.5. In actual production, the continuous flow tubular reactor can also be provided with the function of continuously monitoring the feed flow rate, feed temperature, and reaction temperature, and can continuously detect the changes in monitoring indicators such as the pH value and infrared spectrum of the reaction material, so as to better monitor the changes in the raw material conversion rate of the synthesis reaction.
[0074] (5) The collected reaction solution is subjected to post-treatment such as filtration, washing, centrifugation, recrystallization, and drying to obtain a solid product. The post-treatment process is as follows: after removing the mother liquor by filtration, the filter cake is dissolved with 700 ml of pure water, the dissolved material is centrifuged to remove the liquid, and then washed with about 5 ml of pure water for 2-3 times, and the water is removed by centrifugation again. The obtained solid product is vacuum-rotated and dried to finally obtain about 162.25 grams of a solid product. The obtained solid product can also be further purified by further recrystallization.
[0075] In this example, the mass yield of the solid product obtained is 96%, the nuclear magnetic purity is 99.1%, and the yield is 95.14% (yield = mass yield * nuclear magnetic purity)
[0076] Take samples for inspection and compare the infrared correlation (>95%) with the NMR spectrum (such as Figure 1 The results are shown in Table 2 below.
[0077] Table 2:
[0078] Test items Detection Methods Standard regulations Test results Infrared correlation Infrared Comparison with standard ≥95% ≥95％ Content determination T(Potentiometric titration) ≥95.0wt% 99.16％ NMR purity Comparison chart >95％ 99.10％ Appearance (color and shape) Observation with naked eyes under natural light Light yellow or off-white powder White powder
[0079] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.
Claims
1. A one-pot method for synthesizing glyphosate, characterized in that: The steps include: (1) mixing material A and phosphorus trichloride to react to obtain a mixture containing glyphosate, wherein the material A contains N-hydroxymethylglycine salt, an acid binder and water, and during the reaction, the pH value of the reaction system is controlled to be not less than 4, and the reaction process is as follows: phosphorus trichloride is hydrolyzed into phosphorous acid and hydrochloric acid, phosphorous acid reacts with N-hydroxymethylglycine salt to generate glyphosate, and at the same time, cations in the N-hydroxymethylglycine salt and cations in the acid binder react with hydrochloric acid to generate corresponding hydrochloride; (2) post-treating the mixture containing glyphosate obtained after the reaction in step (1) to obtain a glyphosate finished product.
2. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: The reaction temperature of step (1) is 0-60°C.
3. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: The reaction temperature of step (1) is 5-35°C.
4. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: In step (1), the pH value of the reaction system is controlled within the range of 4-6.
5. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: The acid binding agent is used to control the pH value of the reaction system to be not less than 4 during the reaction process, and the acid binding agent is at least one of a soluble carbonate or a bicarbonate.
6. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: In the material A, the mass fraction of the N-hydroxymethylglycine salt is 1-30%; preferably, the N-hydroxymethylglycine salt in the material A is at least one of sodium N-hydroxymethylglycine, potassium N-hydroxymethylglycine, and ammonium N-hydroxymethylglycine.
7. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: In the material A, the mass fraction of the N-hydroxymethylglycine salt is 15-25%.
8. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: The post-treatment in step (2) includes at least one of filtration, washing, dehydration, recrystallization and drying.
9. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: The one-pot method refers to a kettle reaction, and the method comprises the following steps: (1.1) placing an aqueous solution of N-hydroxymethylglycine salt into a reaction kettle, adding an acid binding agent and stirring until a milky white uniform suspension and a well-dispersed suspension are formed, as material A; preferably, the N-hydroxymethylglycine salt is sodium N-hydroxymethylglycine; (1.2) adding phosphorus trichloride dropwise to the suspension, controlling the reaction temperature at 0-60° C., controlling the pH value of the reaction system at 4-6, and after the reaction is completed, cooling to room temperature, discharging the material, filtering, and obtaining a crude glyphosate; (1.3) The crude glyphosate is washed with water, dehydrated and dried to obtain a finished glyphosate product.
10. The one-pot method for synthesizing glyphosate according to claim 1, characterized in that: The one-pot method refers to a continuous flow reaction, and the method comprises the following steps: (1-1) N-hydroxymethylglycine salt, an acid binding agent and water are fully stirred and mixed to form a uniformly mixed suspension as material A; preferably, the N-hydroxymethylglycine salt is sodium N-hydroxymethylglycine; (1-2) controlling the feed temperature of the material A to be 25-50° C., the feed temperature of the phosphorus trichloride to be 0-15° C., and setting the reaction temperature of the continuous flow reactor to be 0-60° C., starting the continuous feeding of the material A and the phosphorus trichloride, respectively controlling the flow rates of the material A and the phosphorus trichloride through the feed pumps, ensuring that the molar amount of the N-hydroxymethylglycine salt in the material A and the molar amount of the phosphorus trichloride enter the mixer at an equal molar flow rate of 1:1, and after rapid mixing in the mixer, entering the continuous flow reactor for reaction, after the reaction is completed, collecting the reaction solution, filtering to obtain a crude glyphosate; (1-3) The crude glyphosate is washed, dehydrated, dried and recrystallized to obtain a finished glyphosate product.