Continuous preparation method of ammonium glyphosate

Abstract

The invention relates to the technical field of organic synthesis, in particular to a continuous preparation method of ammonium glyphosate, which comprises the following steps: S1, pre-adding an ammonium glyphosate solution into a batching kettle, then adding glyphosate raw powder and an aqueous solution, and uniformly stirring and mixing to form a slurry containing a glyphosate solid; s2, simultaneously pumping the slurry containing the glyphosate solid and ammonia gas into a micro-channel reactor for reaction to obtain a material A; s3, the material A is divided into two paths to flow into a batching kettle and a material receiving kettle, and the mass ratio of the material A flowing into the batching kettle to the material A flowing into the material receiving kettle is (2-4): 1; s4, adding methanol into the material receiving kettle, and stirring to obtain a crystallized material; s5, mixing ammonium glyphosate particles obtained by centrifuging the crystal material with an auxiliary agent to obtain a semi-finished product; and S6, heating and drying the semi-finished product to obtain the ammonium glyphosate. According to the continuous preparation method of the ammonium glyphosate, provided by the invention, the raw materials can be fully utilized, the reaction conversion rate and the production efficiency are improved, and meanwhile, the cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a continuous preparation method of glyphosate ammonium salt. Background Art

[0002] Glyphosate is a highly effective, low-toxic broad-spectrum herbicide. It is highly systemic and transmissive, and the green part of the plant absorbs the liquid and conducts it to the root, causing the root to rot and wither and die. Since glyphosate acid has a very low solubility in water and is almost insoluble in water, and the solubility of glyphosate salts is much greater than that of glyphosate acid, and it does not lose the herbicidal activity of its parent compound, the active substance glyphosate is usually processed in the form of a water-soluble salt in a commercial composition. At present, the main popular glyphosate soluble salts on the market are: potassium salt, sodium salt, ammonium salt, isopropylamine salt, dimethylamine salt, ethanolamine salt, etc.

[0003] Glyphosate ammonium salt can be used for weeding in forests, rubber plantations, orchards, tea gardens, mulberry gardens, sugarcane fields, farmlands, railways, airports, warehouses, oil depots and pastures. And the cost of glyphosate ammonium salt is low, therefore, glyphosate ammonium salt is a very common glyphosate preparation. If glyphosate ammonium salt is prepared into high-load granules, transportation costs will be greatly reduced. In the prior art, glyphosate ammonium salt is usually prepared by solid-liquid method, solid-solid method, liquid ammonia method, etc.

[0004] Chinese invention patent CN1724547A discloses a method for producing ammonium glyphosate, which uses solid glyphosate as a stationary phase and aqueous ammonia as a mobile phase to directly react in a reaction tower to obtain a dilute solution of ammonium glyphosate. However, the process has the following disadvantages: in order to obtain solid ammonium salt, the dilute solution needs to be concentrated, which consumes a lot of energy; in the later stage of the reaction, the glyphosate particles become very small, which increases the mass transfer resistance, resulting in incomplete reaction and serious side reactions. Summary of the invention

[0005] In order to solve the problems in the prior art, the present invention provides a continuous preparation method of glyphosate ammonium salt, comprising the following steps:

[0006] S1, adding glyphosate ammonium salt solution to a batching kettle, and then adding glyphosate raw powder and aqueous solution, stirring and mixing to form a slurry containing glyphosate solids;

[0007] S2, injecting the slurry containing glyphosate solid and ammonia gas into a microchannel reactor at the same time to react and obtain material A;

[0008] S3, the material A is divided into two paths and flows into the batching kettle and the receiving kettle, and the mass ratio of the material A flowing into the batching kettle to the material A flowing into the receiving kettle is 2-4:1;

[0009] S4, adding methanol to the collecting kettle, stirring to obtain a crystallized material;

[0010] S5, mixing the glyphosate ammonium salt particles obtained by centrifuging the crystallized material with an adjuvant to prepare a semi-finished product;

[0011] S6. Heat and dry the semi-finished product to obtain glyphosate ammonium salt.

[0012] In one embodiment, the mass concentration of glyphosate ammonium salt in the glyphosate ammonium salt solution in step S1 is 30-50%.

[0013] In one embodiment, the mass concentration of glyphosate ammonium salt in the glyphosate ammonium salt solution in step S1 is 35-45%.

[0014] In one embodiment, the glyphosate ammonium salt solution in step S1 is pumped into the batching kettle at a flow rate of 18.75-33.7 g / min. When material A in step S3 flows back to the batching kettle, the addition of the glyphosate ammonium salt solution is stopped.

[0015] In one embodiment, the glyphosate raw powder and aqueous solution are pumped into the batching kettle at flow rates of 2-4 g / min and 2-10 g / min, respectively.

[0016] In one embodiment, the content of glyphosate solids in the slurry containing glyphosate solids is 8-30 wt %.

[0017] In one embodiment, the content of glyphosate solids in the slurry containing glyphosate solids is 8-10 wt %.

[0018] In one embodiment, in step S2, the slurry containing glyphosate solids and ammonia gas are pumped into the microchannel reactor at flow rates of 20-50 g / min and 400-2580 mL / min, respectively.

[0019] In one embodiment, in step S2, ammonia is pumped into the microchannel reactor at a flow rate of 400-860 mL / min.

[0020] In one embodiment, the reaction time of the slurry containing glyphosate solids and ammonia in the microchannel reactor is 60-150 seconds.

[0021] In one embodiment, the temperature of the microchannel reactor in step S2 is ≤ 60°C.

[0022] In one embodiment, the turbidity of the material A is less than 3.0 NTU, and the pH is controlled at 6-8.

[0023] In one embodiment, the flow rate of material A flowing into the batching kettle in step S3 is 18.75-33.7 g / min.

[0024] In one embodiment, the tail gas from the collecting kettle in step S3 is subjected to secondary treatment to recover methanol and ammonia respectively.

[0025] In one embodiment, the secondary treatment is specifically to cool the tail gas from the collecting kettle through a condenser to recover methanol, and absorb the cooled tail gas with water to recover ammonia.

[0026] In the present invention, 3-4 receiving kettles can be provided. After a certain amount of the reacted material is collected, it can be switched to another receiving kettle to continue collecting the material. At the same time, the tail gas of the receiving kettle is subjected to a cooling treatment. On the one hand, the methanol therein can be condensed and recovered. On the other hand, the cooled tail gas contains unreacted ammonia, which is then absorbed by water and used for the preparation of the slurry containing glyphosate solids in step S1.

[0027] In one embodiment, the stirring speed in step S4 is controlled at 30 r / min-90 r / min, and the stirring time is controlled at 110-130 min.

[0028] In one embodiment, the auxiliary agent in step S5 is selected from one or more of alkyl polysaccharide, tea saponin, organosilicon, and hydroxysulfobetaine.

[0029] In one embodiment, the mass ratio of the auxiliary agent to the glyphosate ammonium salt particles obtained after centrifugation is 0.19-0.25:1.

[0030] Beneficial Effects

[0031] 1. The present invention adopts a microchannel reactor to carry out ammonia reaction, and controls the flow rate of the slurry containing glyphosate solid and ammonia gas, so that the utilization rate of ammonia gas is high and the reaction conversion rate is improved.

[0032] 2. The continuous preparation method of glyphosate ammonium salt provided by the present invention can monitor the turbidity and pH of the solution online and regularly, eliminating the problem of long reaction cycle caused by the need for sampling, testing, feeding and then reaction in traditional kettle reactions.

[0033] 3. The continuous preparation method of glyphosate ammonium salt provided by the present invention partially refluxes the material prepared by the microchannel reactor, and controls the amount of the refluxed material to ensure that a slurry containing 8-30% glyphosate solids is formed in the batching kettle, which is beneficial to the precipitation of glyphosate ammonium salt particles.

[0034] 4. The continuous preparation method of glyphosate ammonium salt provided by the present invention can fully utilize the raw materials, reduce the generation of by-products, improve production efficiency and reduce costs.

[0035] 5. In the present invention, the entire process of feeding, heating, cooling and mixing reaction in the microchannel reactor is a continuous flow reaction, which avoids the safety hazards and environmental pollution caused by leakage during material transfer in conventional production, and is easy to prepare glyphosate ammonium salt industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The figure is a flow chart of the continuous preparation process of glyphosate ammonium salt. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the examples and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The experimental methods for which specific conditions are not specified in the examples are carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be purchased commercially.

[0038] Example 1

[0039] This embodiment provides a continuous preparation method of glyphosate ammonium salt, comprising the following steps:

[0040] S1, pre-adding 41.3% glyphosate ammonium salt solution into the batching kettle at a flow rate of 18.75 g / min, then adding glyphosate raw powder and aqueous solution, stirring and mixing to form a slurry containing glyphosate solids; when material A in step S3 flows back to the batching kettle, stop adding glyphosate ammonium salt solution;

[0041] S2, pumping the slurry containing glyphosate solid and ammonia gas into the microchannel reactor at flow rates of 25 g / min and 716 mL / min respectively to react to obtain material A;

[0042] S3, the material A is divided into two paths and flows into the batching kettle and the receiving kettle, and the mass ratio of the material A flowing into the batching kettle to the material A flowing into the receiving kettle is 3:1;

[0043] S4, add 1500mL of methanol to the collecting kettle, control the speed at 80r / min and stir to obtain crystallized material, continue feeding for 120min, then switch the collecting kettle to collect material A;

[0044] S5, mixing 362.7 g of glyphosate ammonium salt particles obtained by centrifugation of the crystallized material with 79.6 g of alkyl polyglycoside to prepare a semi-finished product;

[0045] S6. Heat and dry the semi-finished product to obtain glyphosate ammonium salt.

[0046] In step S1, the glyphosate raw powder and aqueous solution are pumped into the batching kettle at flow rates of 2.5 g / min and 3.75 g / min, respectively.

[0047] The content of glyphosate solids in the slurry containing glyphosate solids in step S1 is 10 wt %.

[0048] The temperature of the microchannel reactor in step S2 is 55° C. The reaction time of the slurry containing glyphosate solids and ammonia in the microchannel reactor is 100 seconds.

[0049] The turbidity of the material A was 2.6 NTU and the pH was 7.1.

[0050] In step S3, the flow rate of material A flowing into the batching kettle is 18.75 g / min.

[0051] In the step S3, the tail gas from the collecting kettle is cooled by a condenser to recover methanol, and the cooled tail gas is absorbed by water to recover ammonia.

[0052] The glyphosate conversion rate was 99%.

[0053] Example 2

[0054] This embodiment provides a continuous preparation method of glyphosate ammonium salt, comprising the following steps:

[0055] S1, pre-adding 38.6% glyphosate ammonium salt solution into the batching kettle at a flow rate of 33.70 g / min, then adding glyphosate raw powder and aqueous solution, stirring and mixing to form a slurry containing glyphosate solids; when material A in step S3 flows back to the batching kettle, stop adding glyphosate ammonium salt solution;

[0056] S2, pumping the slurry containing glyphosate solid and ammonia gas into the microchannel reactor at flow rates of 43.7 g / min and 774 mL / min respectively to react to obtain material A;

[0057] S3, the material A is divided into two paths and flows into the batching kettle and the receiving kettle, and the mass ratio of the material A flowing into the batching kettle to the material A flowing into the receiving kettle is 3.4:1;

[0058] S4, add 3000mL of methanol to the collecting kettle, control the speed at 50r / min and stir to obtain crystallized material, continue feeding for 120min, then switch the collecting kettle to collect material A;

[0059] S5, mixing 506.3 g of glyphosate ammonium salt particles obtained by centrifugation of the crystallized material with 101.2 g of tea saponin to prepare a semi-finished product;

[0060] S6. Heat and dry the semi-finished product to obtain glyphosate ammonium salt.

[0061] In step S1, the glyphosate raw powder and aqueous solution are pumped into the batching kettle at flow rates of 3.5 g / min and 6.5 g / min, respectively.

[0062] The content of glyphosate solids in the slurry containing glyphosate solids in step S1 is 8 wt %.

[0063] The temperature of the microchannel reactor in step S2 is 50° C. The reaction time of the slurry containing glyphosate solids and ammonia in the microchannel reactor is 90 seconds.

[0064] The turbidity of the material A was 2.5 NTU and the pH was 6.9.

[0065] In the step S3, the flow rate of material A flowing into the batching kettle is 33.70 g / min.

[0066] In the step S3, the tail gas from the collecting kettle is cooled by a condenser to recover methanol, and the cooled tail gas is absorbed by water to recover ammonia.

[0067] The glyphosate conversion rate was 98%.

[0068] Comparative Example 1

[0069] This comparative example provides an intermittent autoclave preparation method of glyphosate ammonium salt, comprising the following steps:

[0070] S1. Add 1500 g of preparation water and 930 g of glyphosate raw powder into a batching kettle, and mix them evenly under stirring to form a glyphosate slurry;

[0071] S2, passing ammonia gas into the glyphosate slurry through an extension tube at a rate of 856 mL / min, the ventilation time is 4 hours, and the preparation temperature is controlled at 55°C;

[0072] S3, after the ventilation is completed, the stirring reaction is continued for 4 hours to obtain material A, and material A enters the receiving kettle;

[0073] S4, add 3000mL methanol into the receiving kettle, stir and crystallize, the stirring speed is 80r / min. Add the glyphosate ammonium salt solution into the receiving kettle and continue stirring;

[0074] S5, mixing 1076.1 g of glyphosate ammonium salt particles obtained by centrifugation of the substance obtained after the reaction in step S4 with 84.5 g of alkyl polyglycoside to prepare a semi-finished product;

[0075] S6. Heat and dry the semi-finished product to obtain glyphosate ammonium salt.

[0076] The glyphosate conversion rate was 90%.

[0077] Comparative Example 2

[0078] This comparative example provides a method for preparing glyphosate ammonium salt, comprising the following steps:

[0079] S1, pre-adding 22.6% glyphosate ammonium salt solution into the batching kettle at a flow rate of 10.01 g / min, then adding glyphosate raw powder and aqueous solution, stirring and mixing to form a slurry containing glyphosate solids; when material A in step S3 flows back to the batching kettle, stop adding glyphosate ammonium salt solution;

[0080] S2, pumping the slurry containing glyphosate solid and ammonia gas into the microchannel reactor at flow rates of 20 g / min and 442 mL / min respectively to react to obtain material A;

[0081] S3, the material A is divided into two paths and flows into the batching kettle and the receiving kettle, and the mass ratio of the material A flowing into the batching kettle and the material A flowing into the receiving kettle is 2:1;

[0082] S4, add 3000mL of methanol to the collecting kettle, control the speed at 50r / min and stir to obtain crystallized material, continue feeding for 120min, then switch the collecting kettle to collect material A;

[0083] S5, mixing 250 g of glyphosate ammonium salt particles obtained by centrifugation of the crystallized material with 101.2 g of tea saponin to prepare a semi-finished product;

[0084] S6. Heat and dry the semi-finished product to obtain glyphosate ammonium salt.

[0085] In step S1, the glyphosate raw powder and aqueous solution are pumped into the batching kettle at flow rates of 2 g / min and 8 g / min, respectively.

[0086] The content of glyphosate solids in the slurry containing glyphosate solids in step S1 is 10 wt %.

[0087] The temperature of the microchannel reactor in step S2 is 50° C. The reaction time of the slurry containing glyphosate solids and ammonia in the microchannel reactor is 100 seconds.

[0088] The turbidity of the material A was 2.5 NTU and the pH was 7.0.

[0089] In the step S3, the flow rate of material A flowing into the batching kettle is 10.01 g / min.

[0090] In the step S3, the tail gas from the collecting kettle is cooled by a condenser to recover methanol, and the cooled tail gas is absorbed by water to recover ammonia.

[0091] The glyphosate conversion rate was 80%.

[0092] Comparative Example 3

[0093] This comparative example provides a method for preparing glyphosate ammonium salt, comprising the following steps:

[0094] S1, pre-adding 41.3% glyphosate ammonium salt solution into the batching kettle at a flow rate of 18.75 g / min, then adding glyphosate raw powder and aqueous solution, stirring and mixing to form a slurry containing glyphosate solids; when material A in step S3 flows back to the batching kettle, stop adding glyphosate ammonium salt solution;

[0095] S2, pumping the slurry containing glyphosate solid and ammonia gas into the microchannel reactor at flow rates of 25 g / min and 360 mL / min respectively to react to obtain material A;

[0096] The content of glyphosate solids in the slurry containing glyphosate solids in step S1 is 10 wt %.

[0097] The temperature of the microchannel reactor in step S2 is 55° C. The reaction time of the slurry containing glyphosate solids and ammonia in the microchannel reactor is 100 seconds.

[0098] The turbidity of the material A was 4.3 NTU and the pH was 2.8.

[0099] In this case, the ammonia feed flow rate was too low, resulting in incomplete glyphosate solid reaction and increased turbidity, which did not meet the quality indicators and could not be used for subsequent experiments. Figure 1 The continuous preparation method of glyphosate ammonium salt in the above-mentioned embodiments and comparative examples can be further understood.

Claims

1. A continuous preparation method of glyphosate ammonium salt, characterized in that: The following steps are involved: S1, adding glyphosate ammonium salt solution to a batching kettle, and then adding glyphosate raw powder and aqueous solution, stirring and mixing to form a slurry containing glyphosate solids; S2, injecting the slurry containing glyphosate solid and ammonia gas into a microchannel reactor at the same time to react and obtain material A; S3, the material A is divided into two paths and flows into the batching kettle and the receiving kettle, and the mass ratio of the material A flowing into the batching kettle to the material A flowing into the receiving kettle is 2-4:1; S4, adding methanol to the collecting kettle, stirring to obtain a crystallized material; S5, mixing the glyphosate ammonium salt particles obtained by centrifuging the crystallized material with an adjuvant to prepare a semi-finished product; S6. Heat and dry the semi-finished product to obtain glyphosate ammonium salt.

2. The continuous preparation method of glyphosate ammonium salt according to claim 1, characterized in that: The mass concentration of glyphosate ammonium salt in the glyphosate ammonium salt solution in step S1 is 30-50%.

3. The continuous preparation method of glyphosate ammonium salt according to claim 1, characterized in that: In the step S1, the glyphosate ammonium salt solution is pumped into the batching kettle at a flow rate of 18.75-33.70 g / min.

4. The continuous preparation method of glyphosate ammonium salt according to claim 1, characterized in that: The glyphosate raw powder and aqueous solution are pumped into the batching kettle at flow rates of 2-4 g / min and 2-10 g / min respectively.

5. The continuous preparation method of glyphosate ammonium salt according to claim 1, characterized in that: The content of glyphosate solid in the glyphosate solid-containing slurry is 8-30 wt %.

6. The continuous preparation method of glyphosate ammonium salt according to claim 1, characterized in that: In the step S2, the slurry containing glyphosate solids and ammonia gas are pumped into the microchannel reactor at flow rates of 20-50 g / min and 400-2580 mL / min, respectively.

7. The continuous preparation method of glyphosate ammonium salt according to claim 6, characterized in that: The reaction time of the slurry containing glyphosate solids and ammonia in the microchannel reactor is 60-150s.

8. The continuous preparation method of glyphosate ammonium salt according to claim 1, characterized in that: The turbidity of the material A is less than 3.0 NTU, and the pH is controlled at 6-8.

9. The continuous preparation method of glyphosate ammonium salt according to claim 1, characterized in that: The auxiliary agent in step S5 is selected from one or more of alkyl polysaccharide, tea saponin, organosilicon, and hydroxysulfobetaine.

10. The continuous preparation method of glyphosate ammonium salt according to claim 9, characterized in that: The mass ratio of the auxiliary agent to the glyphosate ammonium salt particles obtained after centrifugation is 0.19-0.25:1.

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