Synthesis process of glyphosate active compound

Abstract

The invention discloses a synthesis process of a glyphosate active compound, which belongs to the technical field of glyphosate synthesis, and comprises the following steps: adding paraformaldehyde and methanol into a synthesis kettle, uniformly stirring and mixing, adding a catalyst I, and carrying out depolymerization reaction; after the depolymerization reaction is finished, adding a catalyst II, preserving heat, fully stirring, and then adding glycine for addition reaction; after the reaction is completed, adding dimethyl phosphite to carry out condensation reaction; after the reaction is finished, pumping into a hydrolysis kettle, dropwise adding hydrochloric acid, heating with steam to evaporate methanol and methylal, then carrying out reflux reaction, evaporating hydrogen chloride under reduced pressure, and then adding water into the kettle; and finally, putting the material in the hydrolysis kettle into a crystallization kettle, cooling, standing, filtering and drying to obtain solid glyphosate. The introduced catalyst not only has a very good catalytic effect, improves the yield of a glyphosate active compound, shortens the glyphosate synthesis time and improves the production efficiency, but also can prevent the formation of glyphosine impurities and other impurities, improves the economic benefits, and is energy-saving and environment-friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of glyphosate synthesis, and particularly relates to a synthesis process of glyphosate technical. Background Art

[0002] Glyphosate is a systemic, broad-spectrum, post-emergence herbicide that kills annual and perennial weeds. When sprayed on weed leaves, it is absorbed and transported to the roots, inhibiting the synthesis of aromatic amino acids and disrupting the biochemical reactions within the weeds, causing the roots to rot and die. It is suitable for use in orchards, mulberry trees, tea plants, cotton fields, sugarcane fields, no-till corn, rubber plantations, paddy field ridges, and no-till direct-seeded rice. Glyphosate is the fastest-growing and best-selling pesticide in the world, with over 4 billion km2 of soil used worldwide. 2 Glyphosate is used for weed control in forestry, orchards, and glyphosate-resistant economic crop planting areas.

[0003] There are numerous synthetic routes for glyphosate, two of which have achieved industrialization: the glycine method and the iminodiacetic acid (IDA) method. The glycine method first synthesizes glycine, which is then combined with other raw materials to form glyphosate. The alkyl ester method is further divided into the dimethyl phosphite method and the trimethyl phosphite method, depending on the type of phosphite. The advantages of the alkyl ester method include mature technology, readily available raw materials, a marketable byproduct, methyl chloride, and low wastewater production; low production costs; large-scale reaction equipment, and automated unit operations. The IDA method first synthesizes IDA, which is then reacted and condensed with other raw materials to produce diglyphosate, which is then oxidized to produce glyphosate. The starting material, IDA (iminodiacetic acid), in the IDA route is synthesized into glyphosate through condensation, crystallization, and redox reactions. The mother liquor processing cost of diglyphosate in the IDA method is high, and the entire technology is not yet fully mature. The aqueous solution produced from the mother liquor contains high formaldehyde content, and separation technology is difficult. The main raw material, diethanolamine, is highly dependent on the international market, making supply difficult to secure and resulting in high production costs.

[0004] In the glycine method, the traditional process only uses triethylamine as a catalyst. During the production process, about 25% of the glycine will undergo side reactions, increasing the glyphosate impurity content to about 15%. The by-products enter the mother liquor and other process wastewater. Not only will the glyphosate yield be very low, affecting economic benefits, but it will also increase the amount of mother liquor produced, increasing environmental pressure.

[0005] Based on this, we proposed a synthesis process for glyphosate technical, hoping to address the shortcomings of the existing technology. Summary of the Invention

[0006] The purpose of the present invention is to provide a synthesis process of glyphosate technical in view of the existing problems.

[0007] The present invention is achieved through the following technical solutions:

[0008] A synthesis process for glyphosate technical comprises the following steps:

[0009] S1, adding paraformaldehyde and methanol into a synthesis reactor, stirring and mixing, and then adding catalyst I to carry out depolymerization reaction;

[0010] S2. After the depolymerization reaction is completed, catalyst II is added and kept warm and stirred thoroughly, and then glycine is added for addition reaction;

[0011] S3, after the reaction is completed, dimethyl phosphite is added to carry out condensation reaction;

[0012] S4. After the reaction is completed, the mixture is poured into a hydrolysis kettle, hydrochloric acid is added dropwise and heated with steam to evaporate methanol and methylal, followed by reflux reaction for 1 to 4 hours, hydrogen chloride is evaporated under reduced pressure, and water is added to the kettle;

[0013] S5. Finally, the material in the hydrolysis kettle is placed into a crystallization kettle, cooled, allowed to stand, filtered, and dried to obtain solid glyphosate.

[0014] Preferably, the preparation of catalyst I described in step S1 comprises the following steps:

[0015] (1) Add diatomaceous earth and deionized water in a weight-to-volume ratio of 1 g: 200-300 mL into a three-necked flask, stir at 80-90° C. for 10-20 min, add nitric acid to adjust the pH to 3-4, and continue stirring for 20-30 min to obtain a suspension for use;

[0016] (2) filtering the suspension until the pH of the filtrate is neutral, recovering the filter cake, drying it, and grinding and mixing it with loess stone in a weight ratio of 20 to 30:1 to obtain a mixed powder for later use;

[0017] (3) After butyl titanate and anhydrous ethanol are stirred and mixed in a volume ratio of 1:60 to 80, lanthanum nitrate, cerium nitrate and the above mixed powder are added, and after ultrasonic dispersion, hydrochloric acid is added dropwise. After aging overnight, the mixture is added to a deep-cold grinder for pulverization to obtain catalyst I for use.

[0018] Preferably, the grinding speed in step (2) is 1000-3000 rpm, and the grinding time is 15-20 min.

[0019] Preferably, the weight-to-volume ratio of lanthanum nitrate to butyl titanate in step (3) is 1-3 g:12-20 mL;

[0020] The amount of cerium nitrate added is in a weight-to-volume ratio of 0.5-1 g to butyl titanate: 3-7 mL;

[0021] The added amount of the mixed powder is such that the weight volume ratio of the mixed powder to butyl titanate is 1-2 g:6-10 mL.

[0022] The concentration of hydrochloric acid is 10-12%, and the amount of hydrochloric acid added is 0.4-0.8 times the volume of butyl titanate.

[0023] Preferably, during the pulverization process in step (3), the temperature in the pulverizer is controlled to be -90 to -50°C, and the pulverization time is 7 to 11 minutes.

[0024] Preferably, the preparation method of catalyst II described in step S2 is: immersing biochar in sodium hydroxide solution, immersing it at a constant temperature for 18 to 24 hours, and then placing it in a rotary evaporator for evaporation. After evaporating the water, it is added to a triethylamine solution, ultrasonically dispersed evenly, immersed at room temperature for 8 to 10 hours, and then vacuum filtered. The filtrate is collected to obtain catalyst II.

[0025] Preferably, the constant temperature immersion temperature is 80-90°C.

[0026] Preferably, the depolymerization reaction temperature is 30-40°C, and the reaction time is 3-5 minutes;

[0027] The addition reaction temperature is 35-45°C, and the reaction time is 20-60 minutes;

[0028] The condensation reaction temperature is 50-60°C, and the reaction time is 30-50 minutes.

[0029] The molar ratio of the paraformaldehyde: catalyst I: methanol: glycine: catalyst II: dimethyl phosphite: hydrochloric acid is 1: 0.03-0.15: 6-10: 0.8-1.2: 0.4-0.9: 0.7-1.1: 1-2.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] The present invention provides a synthesis process for glyphosate technical. Catalyst I and catalyst II prepared by a specific method are introduced into the synthesis process. The catalysts are used in combination with each other to significantly improve the yield and purity of the glyphosate technical, with the yield reaching as high as 95.23%. The catalysts introduced in the present invention not only have a good catalytic effect, improve the yield of the glyphosate technical, shorten the glyphosate synthesis time, and improve production efficiency, but also prevent the formation of impurities such as glyphosate-enhancing impurities, thereby improving economic benefits and being energy-saving and environmentally friendly.

[0032] First, a mixed powder of diatomaceous earth and loess stone is used as a carrier to load a rare earth compound, forming a surface-crosslinked, highly stable, and highly active catalyst. This accelerates the depolymerization of paraformaldehyde, improving reaction efficiency and product purity. Furthermore, based on extensive experiments, the inventors adjusted the raw material ratios and processing parameters to achieve a small particle size (pore size 2-3 mm), large specific surface area, complex and diverse pores, and a highly polar molecular structure with rich functional groups and a strong Coulomb field. This promotes dehydration, further improving reaction efficiency, reducing the formation of byproducts, and increasing product purity.

[0033] Secondly, the impregnation is carried out at a specific temperature. Sodium hydroxide acts on the biochar, which will undergo redox reactions and acid-base neutralization reactions with the groups in the biochar, produce certain etching on the surface of the biochar, cause the destruction of the carbon skeleton, increase the porosity and pore size, and at the same time, form new functional groups, which further improve the activity of the biochar. When added to the triethylamine solution, it has a dehydrating effect on the triethylamine, enhances the activity of the triethylamine, improves the synthesis efficiency, reduces the occurrence of side reactions, and further changes the porosity and pore size of the biochar, so that the pores of the biochar are of appropriate size. Without affecting the catalytic activity, it can absorb moisture and avoid the consumption of dimethyl phosphite by moisture, thereby increasing the yield of glyphosate.

[0034] Finally, the two catalysts cooperate with each other to achieve a certain additive effect, breaking the technical limitations of traditional triethylamine as a catalyst. This not only provides a new idea for the synthesis process of glyphosate technical, but also provides a high-activity, high-stability, high-selectivity, and superior-performance catalyst for the chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the effect diagram of catalyst I on glyphosate yield. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] Example 1

[0038] A synthesis process for glyphosate technical comprises the following steps:

[0039] S1. Add paraformaldehyde and methanol into a synthesis reactor, stir and mix, then add catalyst I and carry out depolymerization reaction at 30°C for 3 minutes;

[0040] S2. After the depolymerization reaction is completed, add catalyst II and keep warm with sufficient stirring, then add glycine and react at 35°C for 20 minutes;

[0041] S3. After the reaction is complete, dimethyl phosphite is added and the condensation reaction is carried out at 50°C for 30 minutes;

[0042] S4. After the reaction is completed, the mixture is poured into a hydrolysis kettle, hydrochloric acid is added dropwise and heated with steam to evaporate methanol and methylal, followed by reflux reaction for 1 hour, hydrogen chloride is evaporated under reduced pressure, and water is added to the kettle;

[0043] S5. Finally, the material in the hydrolysis kettle is placed into a crystallization kettle, cooled, allowed to stand, filtered, and dried to obtain solid glyphosate.

[0044] The molar ratio of the paraformaldehyde: catalyst I: methanol: glycine: catalyst II: dimethyl phosphite: hydrochloric acid is 1:0.03:6:0.8:0.4:0.7:1.

[0045] The preparation of the catalyst I comprises the following steps:

[0046] (1) Add diatomaceous earth and deionized water in a weight-to-volume ratio of 1 g:200 mL into a three-necked flask, stir at 80°C for 10 min, add nitric acid to adjust the pH to 3, and continue stirring for 20 min to obtain a suspension for use;

[0047] (2) After filtering the suspension until the pH of the filtrate is neutral, the filter cake is recovered, dried, and mixed with loess stone in a weight ratio of 20:1, and ground at 1000 rpm for 15 min to obtain a mixed powder for later use;

[0048] (3) After mixing butyl titanate and anhydrous ethanol in a volume ratio of 1:60, lanthanum nitrate, cerium nitrate and the above mixed powder were added, and after ultrasonic dispersion, hydrochloric acid was added dropwise. After aging overnight, the mixture was added to a cryogenic mill and pulverized at -90°C for 7 minutes to obtain catalyst I for use;

[0049] The weight-to-volume ratio of lanthanum nitrate to butyl titanate is 1 g:12 mL;

[0050] The amount of cerium nitrate added was in a weight-to-volume ratio of 0.5 g to butyl titanate: 3 mL;

[0051] The added amount of the mixed powder is such that the weight volume ratio of the mixed powder to butyl titanate is 1 g:6 mL.

[0052] The concentration of hydrochloric acid is 10%, and the amount of hydrochloric acid added is 0.4 times the volume of butyl titanate.

[0053] The preparation method of the catalyst II is as follows: immersing the biochar in a sodium hydroxide solution, immersing it at a constant temperature of 80°C for 18 hours, and then placing it in a rotary evaporator for evaporation. After evaporating the water, the biochar is added to a triethylamine solution, ultrasonically dispersed evenly, immersed at room temperature for 8 hours, and then vacuum filtered. The filtrate is collected to obtain the catalyst II.

[0054] Example 2

[0055] A synthesis process for glyphosate technical comprises the following steps:

[0056] S1. Add paraformaldehyde and methanol into a synthesis reactor, stir and mix, then add catalyst I and carry out depolymerization reaction at 35°C for 4 minutes;

[0057] S2. After the depolymerization reaction is completed, add catalyst II and keep warm with sufficient stirring, then add glycine and react at 40°C for 40 minutes;

[0058] S3. After the reaction is complete, dimethyl phosphite is added and the condensation reaction is carried out at 55°C for 40 minutes;

[0059] S4, after the reaction is completed, put it into a hydrolysis kettle, add hydrochloric acid dropwise and heat with steam to evaporate methanol and methylal, then reflux for 2.5h, evaporate hydrogen chloride under reduced pressure and then add water to the kettle;

[0060] S5. Finally, the material in the hydrolysis kettle is placed into a crystallization kettle, cooled, allowed to stand, filtered, and dried to obtain solid glyphosate.

[0061] The molar ratio of the paraformaldehyde: catalyst I: methanol: glycine: catalyst II: dimethyl phosphite: hydrochloric acid is 1:0.09:8:1:0.6:0.9:1.5.

[0062] The preparation of the catalyst I comprises the following steps:

[0063] (1) Add diatomaceous earth and deionized water in a weight-to-volume ratio of 1 g:250 mL into a three-necked flask, stir at 85°C for 15 min, then add nitric acid to adjust the pH to 3.5, and continue stirring for 25 min to obtain a suspension for use;

[0064] (2) After filtering the suspension until the pH of the filtrate is neutral, recover the filter cake, dry it, and grind it with loess stone at a weight ratio of 25:1 at 2000 rpm for 17.5 min to obtain a mixed powder for later use;

[0065] (3) After mixing butyl titanate and anhydrous ethanol in a volume ratio of 1:70, lanthanum nitrate, cerium nitrate and the above mixed powder were added, and after ultrasonic dispersion, hydrochloric acid was added dropwise. After aging overnight, the mixture was added to a deep-cold mill and pulverized at -70°C for 9 minutes to obtain Catalyst I for use;

[0066] The weight-to-volume ratio of lanthanum nitrate to butyl titanate is 2 g:16 mL;

[0067] The amount of cerium nitrate added was in a weight-to-volume ratio of 0.7 g to butyl titanate: 5 mL;

[0068] The weight-to-volume ratio of the mixed powder to butyl titanate was 1.5 g:8 mL.

[0069] The concentration of hydrochloric acid was 11%, and the amount of hydrochloric acid added was 0.6 times the volume of butyl titanate.

[0070] The preparation method of the catalyst II is as follows: immersing the biochar in a sodium hydroxide solution, immersing it at a constant temperature of 85°C for 21 hours, and then placing it in a rotary evaporator for evaporation. After evaporating the water, the biochar is added to a triethylamine solution, ultrasonically dispersed evenly, immersed at room temperature for 9 hours, and then vacuum filtered. The filtrate is collected to obtain the catalyst II.

[0071] Example 3

[0072] A synthesis process for glyphosate technical comprises the following steps:

[0073] S1. Add paraformaldehyde and methanol into a synthesis reactor, stir and mix, then add catalyst I and carry out depolymerization reaction at 40°C for 5 minutes;

[0074] S2. After the depolymerization reaction is completed, add catalyst II and keep warm with sufficient stirring, then add glycine and react at 45°C for 60 minutes;

[0075] S3. After the reaction is completed, dimethyl phosphite is added and the condensation reaction is carried out at 60°C for 50 minutes;

[0076] S4, after the reaction is completed, the reaction is poured into a hydrolysis kettle, hydrochloric acid is added dropwise and heated with steam to evaporate methanol and methylal, and then refluxed for 4 hours, hydrogen chloride is evaporated under reduced pressure, and water is added to the kettle;

[0077] S5. Finally, the material in the hydrolysis kettle is placed into a crystallization kettle, cooled, allowed to stand, filtered, and dried to obtain solid glyphosate.

[0078] The molar ratio of the paraformaldehyde: catalyst I: methanol: glycine: catalyst II: dimethyl phosphite: hydrochloric acid is 1:0.15:10:1.2:0.9:1.1:2.

[0079] The preparation of the catalyst I comprises the following steps:

[0080] (1) Add diatomaceous earth and deionized water in a weight-to-volume ratio of 1 g:300 mL into a three-necked flask, stir at 90°C for 20 min, add nitric acid to adjust the pH to 4, and continue stirring for 30 min to obtain a suspension for use;

[0081] (2) After filtering the suspension until the pH of the filtrate is neutral, recover the filter cake, dry it, and grind it with loess stone at a weight ratio of 30:1 at 3000 rpm for 20 min to obtain a mixed powder for later use;

[0082] (3) After mixing butyl titanate and anhydrous ethanol in a volume ratio of 1:80, lanthanum nitrate, cerium nitrate and the above mixed powder were added, and after ultrasonic dispersion, hydrochloric acid was added dropwise. After aging overnight, the mixture was added to a deep-cold mill and pulverized at -50°C for 11 minutes to obtain Catalyst I for use;

[0083] The weight-to-volume ratio of lanthanum nitrate to butyl titanate is 3 g:20 mL;

[0084] The amount of cerium nitrate added was in a weight-to-volume ratio of 1 g to butyl titanate: 7 mL;

[0085] The added amount of the mixed powder was such that the weight-to-volume ratio of the mixed powder to butyl titanate was 2 g:10 mL.

[0086] The concentration of hydrochloric acid is 12%, and the amount of hydrochloric acid added is 0.8 times the volume of butyl titanate.

[0087] The preparation method of the catalyst II is as follows: immersing the biochar in a sodium hydroxide solution, immersing it at a constant temperature of 90°C for 24 hours, and then placing it in a rotary evaporator for evaporation. After evaporating the water, the biochar is added to a triethylamine solution, ultrasonically dispersed evenly, immersed at room temperature for 10 hours, and then vacuum filtered to collect the filtrate to obtain the catalyst II.

[0088] Comparative Example 1

[0089] A synthesis process for glyphosate technical comprises the following steps:

[0090] S1. Add paraformaldehyde and methanol into a synthesis reactor and stir to mix thoroughly. Then add catalyst II and keep warm and stir thoroughly. Then add glycine and react at 40℃ for 40min.

[0091] S2. After the reaction is completed, dimethyl phosphite is added and the condensation reaction is carried out at 55°C for 40 minutes;

[0092] S3, after the reaction is completed, put it into a hydrolysis kettle, add hydrochloric acid dropwise and heat with steam to evaporate methanol and methylal, then reflux for 2.5h, evaporate hydrogen chloride under reduced pressure and then add water to the kettle;

[0093] S4. Finally, the material in the hydrolysis kettle is placed into a crystallization kettle, cooled, allowed to stand, filtered, and dried to obtain solid glyphosate.

[0094] The molar ratio of the paraformaldehyde:methanol:glycine:catalyst II:dimethyl phosphite:hydrochloric acid is 1:8:1:0.6:0.9:1.5.

[0095] The preparation method of the catalyst II is as follows: immersing the biochar in a sodium hydroxide solution, immersing it at a constant temperature of 85°C for 21 hours, and then placing it in a rotary evaporator for evaporation. After evaporating the water, the biochar is added to a triethylamine solution, ultrasonically dispersed evenly, immersed at room temperature for 9 hours, and then vacuum filtered. The filtrate is collected to obtain the catalyst II.

[0096] Comparative Example 2

[0097] A synthesis process for glyphosate technical comprises the following steps:

[0098] S1. Add paraformaldehyde and methanol into a synthesis reactor, stir and mix, then add catalyst I and carry out depolymerization reaction at 35°C for 4 minutes;

[0099] S2. After the depolymerization reaction is completed, triethylamine is added and kept warm with sufficient stirring, and then glycine is added and reacted at 40°C for 40 minutes;

[0100] S3. After the reaction is complete, dimethyl phosphite is added and the condensation reaction is carried out at 55°C for 40 minutes;

[0101] S4, after the reaction is completed, put it into a hydrolysis kettle, add hydrochloric acid dropwise and heat with steam to evaporate methanol and methylal, then reflux for 2.5h, evaporate hydrogen chloride under reduced pressure and then add water to the kettle;

[0102] S5. Finally, the material in the hydrolysis kettle is placed into a crystallization kettle, cooled, allowed to stand, filtered, and dried to obtain solid glyphosate.

[0103] The molar ratio of the paraformaldehyde: catalyst I: methanol: glycine: triethylamine: dimethyl phosphite: hydrochloric acid is 1:0.09:8:1:0.6:0.9:1.5.

[0104] The preparation of the catalyst I comprises the following steps:

[0105] (1) Add diatomaceous earth and deionized water in a weight-to-volume ratio of 1 g:250 mL into a three-necked flask, stir at 85°C for 15 min, then add nitric acid to adjust the pH to 3.5, and continue stirring for 25 min to obtain a suspension for use;

[0106] (2) After filtering the suspension until the pH of the filtrate is neutral, recover the filter cake, dry it, and grind it with loess stone at a weight ratio of 25:1 at 2000 rpm for 17.5 min to obtain a mixed powder for later use;

[0107] (3) After mixing butyl titanate and anhydrous ethanol in a volume ratio of 1:70, lanthanum nitrate, cerium nitrate and the above mixed powder were added, and after ultrasonic dispersion, hydrochloric acid was added dropwise. After aging overnight, the mixture was added to a deep-cold mill and pulverized at -70°C for 9 minutes to obtain Catalyst I for use;

[0108] The weight-to-volume ratio of lanthanum nitrate to butyl titanate is 2 g:16 mL;

[0109] The amount of cerium nitrate added was in a weight-to-volume ratio of 0.7 g to butyl titanate: 5 mL;

[0110] The weight-to-volume ratio of the mixed powder to butyl titanate was 1.5 g:8 mL.

[0111] The concentration of hydrochloric acid was 11%, and the amount of hydrochloric acid added was 0.6 times the volume of butyl titanate.

[0112] Detection test

[0113] The yield, purity and glyphosate content of the glyphosate technical obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were tested.

[0114] The test results are shown in Table 1 below.

[0115] Table 1 Yield and purity of glyphosate technical in each example and comparative example

[0116]

[0117] As can be seen from Table 1 above, the glyphosate impurity content in the glyphosate technical obtained in Examples 1 to 3 ranges from 0.26% to 0.31%, which is much lower than the glyphosate impurity content in the glyphosate technical produced by the traditional glycine method, with a reduction of about 80%. Compared with Comparative Examples 1 to 2, it can be seen that the glyphosate yield in Examples 1 to 3 reaches 90.89% to 95.23%, and the purity reaches 99.10% to 99.53%, which has significant advantages.

[0118] On the basis of the above test results, and taking Example 2 as the basis, except for the amount of catalyst I being different, the rest is the same as Example 2, and the effect of the addition amount of catalyst I on the glyphosate yield is tested.

[0119] The experimental results are as follows Figure 1 shown.

[0120] Depend on Figure 1 It can be seen that the yield of glyphosate shows a trend of first increasing and then decreasing with the increase in the amount of catalyst I added, and the addition of catalyst I has a very obvious effect on the improvement of the yield, indicating that the addition of catalyst I has a significant effect on the yield of glyphosate, and there is a certain dosage effect.

[0121] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A synthesis process of glyphosate technical, characterized in that: The steps include: S1, adding paraformaldehyde and methanol into a synthesis reactor, stirring and mixing, and then adding catalyst I to carry out depolymerization reaction; S2. After the depolymerization reaction is completed, add catalyst II, keep warm and stir thoroughly, and then add glycine for addition reaction; S3, after the reaction is completed, dimethyl phosphite is added to carry out condensation reaction; S4, after the reaction is completed, the mixture is poured into a hydrolysis kettle, hydrochloric acid is added dropwise and heated with steam to evaporate methanol and methylal, and then refluxed for 1 to 4 hours, hydrogen chloride is evaporated under reduced pressure, and then water is added to the kettle; S5. Finally, the material in the hydrolysis kettle is placed in a crystallization kettle, cooled, allowed to stand, filtered, and dried to obtain solid glyphosate.

2. A synthesis process of glyphosate technical according to claim 1, characterized in that: The preparation of the catalyst I described in step S1 comprises the following steps: (1) adding diatomaceous earth and deionized water in a weight volume ratio of 1 g: 200-300 mL into a three-necked flask, stirring at 80-90° C. for 10-20 min, adding nitric acid to adjust the pH to 3-4, and continuing to stir for 20-30 min to obtain a suspension for use; (2) filtering the suspension until the pH of the filtrate is neutral, recovering the filter cake, drying it, grinding it with loess stone at a weight ratio of 20 to 30:1 to obtain a mixed powder for later use; (3) After butyl titanate and anhydrous ethanol are stirred and mixed at a volume ratio of 1:60 to 80, lanthanum nitrate, cerium nitrate and the above mixed powder are added, and after ultrasonic dispersion, hydrochloric acid is added dropwise. After aging overnight, the mixture is added to a deep-cold pulverizer for pulverization to obtain Catalyst I for use.

3. A synthesis process of glyphosate technical according to claim 2, characterized in that: The grinding speed in step (2) is 1000-3000 rpm, and the grinding time is 15-20 min.

4. A synthesis process of glyphosate technical according to claim 2, characterized in that: The weight volume ratio of lanthanum nitrate to butyl titanate described in step (3) is 1-3 g:12-20 mL; The added amount of cerium nitrate is in a weight volume ratio of 0.5-1 g:3-7 mL to butyl titanate; The added amount of the mixed powder is 1-2 g:6-10 mL in weight volume ratio with butyl titanate; The concentration of hydrochloric acid is 10-12%, and the amount of hydrochloric acid added is 0.4-0.8 times the volume of butyl titanate.

5. A synthesis process of glyphosate technical according to claim 2, characterized in that: During the pulverization process in step (3), the temperature in the pulverizer is controlled to be -90 to -50°C, and the pulverization time is 7 to 11 minutes.

6. A synthesis process of glyphosate technical according to claim 1, characterized in that: The preparation method of catalyst II described in step S2 is: immerse the biochar in a sodium hydroxide solution, immerse it at a constant temperature for 18 to 24 hours, then place it in a rotary evaporator for evaporation, add it to a triethylamine solution after evaporating the water, ultrasonically disperse it evenly, immerse it at room temperature for 8 to 10 hours, and then vacuum filter it, and collect the filtrate to obtain catalyst II.

7. A synthesis process of glyphosate technical according to claim 6, characterized in that: The temperature of the constant temperature immersion is 80-90°C.

8. A synthesis process of glyphosate technical according to claim 1, characterized in that: The depolymerization reaction temperature is 30-40°C and the reaction time is 3-5min; The addition reaction temperature is 35-45°C and the reaction time is 20-60 min; The condensation reaction temperature is 50-60°C, and the reaction time is 30-50 minutes.

9. A synthesis process of glyphosate technical according to claim 1, characterized in that: The molar ratio of the polyformaldehyde: catalyst I: methanol: glycine: catalyst II: dimethyl phosphite: hydrochloric acid is 1: 0.03-0.15: 6-10: 0.8-1.2: 0.4-0.9: 0.7-1.1: 1-2.

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