Device and production process for continuously synthesizing glycine-method glyphosate

Abstract

The invention relates to a device and a production process for continuously synthesizing glyphosate by a glycine method. Comprising a synthetic liquid tank (1), a triethylamine tank (2), a dimethyl phosphite tank (3), an esterification kettle (4), a circulating pump (5), a loop reactor (6), a synthetic liquid buffer kettle (7), an acidification system (8), a dealcoholization and deacidification system (9) and a crystallization centrifugation system (10), the synthetic liquid tank (1) and the triethylamine tank (2) are respectively connected with the esterification kettle (4), and the dimethyl phosphite tank (3) is connected with an inlet of the loop reactor (6). The bottom of the esterification kettle (4) is connected with an inlet of the loop reactor (6) through the circulating pump (5), an outlet of the loop reactor (6) is connected with an inlet of the esterification kettle (4), and the esterification kettle (4), the acidification system (8), the dealcoholization and deacidification system (9) and the crystallization centrifugal system (10) are sequentially connected. The generation of side reaction is effectively inhibited, and the total yield of glyphosate is greater than or equal to 85%.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticides, and in particular to a device and a production process for continuously synthesizing glyphosate using the glycine method. Background Art

[0002] Glyphosate, a highly effective and broad-spectrum herbicide, has become a key player in the global herbicide market due to its excellent weed control efficacy and wide range of applications, playing a key role in improving agricultural production efficiency. In terms of production and preparation, glyphosate synthesis is primarily achieved through two pathways: the glycine method and the IDA method. The glycine method is favored due to its relatively mature process. It utilizes a series of meticulous steps, including depolymerization, synthesis, acidification, dealcoholization and deacidification, and crystallization and centrifugation, to ultimately produce high-quality glyphosate products. Currently, these steps are primarily accomplished in the industry using batch production methods. Although there have been reports of continuous production of acidification, dealcoholization and deacidification, continuous production has not yet been fully adopted. Notably, patents have been published for the continuous glyphosate synthesis process using microchannel technology. However, due to the high initial investment required for microchannel reactor equipment and relatively limited production capacity, this technology still faces certain limitations in large-scale industrial production. With continued technological advancements and gradual cost reductions, the application prospects of microchannel reactors in glyphosate production are promising.

[0003] Chinese invention patent CN111205319B discloses a continuous glyphosate synthesis method and system. The glyphosate synthesis process includes a continuous acidification and gaseous byproduct purification process, but the synthesis process is not described in detail. Chinese invention patent CN102775441B discloses a continuous production method for glyphosate synthesis liquid, noting the beneficial effect of adding a co-catalyst during the depolymerization process. The subsequent synthesis process utilizes a combination of autoclave and tubular reactors, but yield and production capacity are not explored. Summary of the Invention

[0004] A first aspect of the present invention provides a device for continuously synthesizing glyphosate via the glycine process, comprising: a synthesis liquid tank, a triethylamine tank, a dimethyl phosphite tank, an esterification kettle, a circulation pump, a loop reactor, a synthesis liquid buffer kettle, an acidification system, a dealcoholization and deacidification system, and a crystallization centrifugal system, wherein the synthesis liquid tank and the triethylamine tank are respectively connected to the esterification kettle, the dimethyl phosphite tank is connected to the inlet of the loop reactor, the bottom of the esterification kettle is connected to the circulation pump and the inlet of the loop reactor, the outlet of the loop reactor is connected to the inlet of the esterification kettle, and the esterification kettle, the acidification system, the dealcoholization and deacidification system, and the crystallization centrifugal system are connected in sequence.

[0005] The esterification kettle is provided with an overflow port, the overflow port (11) is connected to the synthetic liquid buffer kettle (7), and the outlet of the loop reactor (6) enters the esterification kettle (4) through an extension pipe.

[0006] Commonly used kettle batch production carries out multiple steps in a single kettle, and equipment utilization is low, which affects capacity improvement. Batch production means batch feeding, and the labor intensity of workers is large, and the possibility of human error is also higher. The application has found that the glycine method continuous production of glyphosate can be realized by the setting of a specific device, effectively improving production efficiency, improving equipment utilization, and reducing manual operation costs. However, due to the matching problem between the reaction raw materials in the continuous feeding, the glyphosate yield is not high. The applicant has further found that a loop reactor is set, and the connection mode of the loop reactor in the device is limited, the conversion rate of dimethyl phosphite can be improved, and the glyphosate yield is improved simultaneously. Since the esterification reaction is an exothermic reaction, it is required to be high for temperature, and it is necessary to timely remove heat from the system, and dimethyl ester is fully reacted as soon as possible. The loop reactor drives dimethyl ester into the reaction system by the material in a large amount of esterification kettles, so that it is fully reacted in a short time, and reaction heat can be removed in time, and the reaction temperature is controlled to a suitable range.

[0007] A second aspect of the present invention provides a production process for continuously synthesizing glyphosate via the glycine method, comprising the following steps:

[0008] S1, adding the synthetic liquid into the esterification kettle through the synthetic liquid tank as the bottom liquid;

[0009] S2, adding dimethyl phosphite to the esterification kettle from the inlet of the loop reactor through the dimethyl phosphite tank, and adding triethylamine to the esterification kettle through the triethylamine tank to carry out esterification reaction;

[0010] S3, the material in the esterification kettle overflows into the synthesis liquid buffer kettle through the overflow port to obtain the esterification liquid;

[0011] S4, the esterified liquid passes through the acidification system, the dealcoholization and deacidification system and the crystallization centrifugation system in sequence to obtain glyphosate.

[0012] The materials in the esterification kettle enter the loop reactor through a circulation pump.

[0013] The raw materials for preparing the synthetic liquid include paraformaldehyde depolymerization product, methanol, triethylamine and glycine.

[0014] Preferably, the raw materials for preparing the synthetic liquid contain 10-18 wt% of glycine, 45-55 wt% of methanol, and 10-20 wt% of triethylamine.

[0015] More preferably, the raw materials for preparing the synthetic liquid contain 11-14 wt% of glycine, 50-55 wt% of methanol, and 14-17 wt% of triethylamine.

[0016] The mass ratio of dimethyl phosphite to synthetic liquid in the esterification kettle is (0.18-0.3):1.

[0017] Preferably, the mass ratio of dimethyl phosphite to synthesis liquid in the esterification kettle is (0.2-0.24):1.

[0018] The material temperature in the loop reactor is 40-50°C; the material temperature in the esterification kettle is 40-50°C.

[0019] Preferably, the material temperature in the loop reactor is 45-50°C; the material temperature in the esterification kettle is 45-50°C.

[0020] The mass ratio of triethylamine added into the esterification kettle by the triethylamine tank to the synthetic liquid is (0.006-0.007):1.

[0021] The present study found that the additional addition of triethylamine can effectively inhibit the occurrence of side reactions and reduce the hydrolysis of dimethyl phosphite, thereby reducing the conversion of glyphosate to glyphosate in the next hydrolysis step and improving the effective utilization rate of P in dimethyl phosphite.

[0022] The circulation flow rate of the circulation pump is 2-5m 3 / h.

[0023] Preferably, the circulation flow rate of the circulation pump is 2-4m 3 / h.

[0024] The pH value of the material in the esterification kettle is maintained at 7-8.

[0025] Preferably, the pH value of the material in the esterification kettle is maintained at 7-7.5.

[0026] The material residence time in the esterification kettle is 0.5-1h.

[0027] Preferably, the material residence time in the esterification kettle is 0.5-0.8h.

[0028] Beneficial effects

[0029] 1. The device of the present application can realize the continuous production of glyphosate by the glycine method, effectively improve production efficiency, increase equipment utilization, and reduce manual operation costs.

[0030] 2. Setting up a loop reactor and limiting the connection method of the loop reactor in the device can improve the conversion rate of dimethyl phosphite and the yield of glyphosate.

[0031] 3. The mass ratio of triethylamine and synthesis liquid added to the esterification kettle is (0.006-0.007):1, which can effectively control the system pH during the esterification process and effectively inhibit the occurrence of side reactions. The total yield of glyphosate is ≥85%.

[0032] 4. By controlling the material residence time in the esterification kettle to 0.5-1h, the glyphosate content is ≥97%.

[0033] 5. Maintaining the pH value of the material in the esterification kettle at 7-8 can reduce the by-product content to below 1% and increase the phosphorus utilization rate to 75%. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The apparatus for the continuous synthesis of glyphosate by the glycine method in the examples includes: 1. Synthesis liquid tank; 2. Triethylamine tank; 3. Dimethyl phosphite tank; 4. Esterification kettle; 5. Circulation pump; 6. Loop reactor; 7. Synthesis liquid buffer kettle; 8. Acidification system; 9. Dealcoholization and deacidification system; 10. Crystallization centrifuge system; 11. Overflow port. DETAILED DESCRIPTION

[0035] Example 1

[0036] A device for continuously synthesizing glyphosate by the glycine method, such as Figure 1 As shown, it includes: a synthesis liquid tank 1, a triethylamine tank 2, a dimethyl phosphite tank 3, an esterification kettle 4, a circulation pump 5, a loop reactor 6, a synthesis liquid buffer kettle 7, an acidification system 8, a dealcoholization and deacidification system 9 and a crystallization centrifugal system 10. The synthesis liquid tank 1 and the triethylamine tank 2 are respectively connected to the esterification kettle 4, the dimethyl phosphite tank 3 is connected to the inlet of the loop reactor 6, the bottom of the esterification kettle 4 is connected to the circulation pump 5 and the inlet of the loop reactor 6, the outlet of the loop reactor 6 is connected to the inlet of the esterification kettle 4, and the esterification kettle 4, the acidification system 8, the dealcoholization and deacidification system 9 and the crystallization centrifugal system 10 are connected in sequence.

[0037] The esterification kettle 4 is provided with an overflow port 11 , which is connected to the synthetic liquid buffer kettle 7 . The outlet of the loop reactor 6 enters the esterification kettle 4 through an extension pipe.

[0038] The materials in the esterification kettle enter the loop reactor through a circulation pump.

[0039] A production process for continuously synthesizing glyphosate via the glycine method comprises the following steps:

[0040] S1, 2m 3 Synthetic liquid is added through synthetic liquid tank 1 to 5m 3 The esterification kettle 4 is used as the bottom liquid;

[0041] S2, dimethyl phosphite is added to the esterification kettle (4) through the dimethyl phosphite tank 3 from the inlet of the loop reactor 6 along with the circulation pump 5, and triethylamine is added to the esterification kettle 4 through the triethylamine tank 2 to carry out the esterification reaction;

[0042] S3, the material in the esterification reactor 4 overflows through the overflow port 11 into the synthetic liquid buffer reactor 7 to obtain the esterification liquid;

[0043] S4, the esterified liquid continues to pass through the acidification system 8, the dealcoholization and deacidification system 9 and the crystallization centrifugation system 10 in sequence to obtain solid glyphosate.

[0044] The material in the esterification kettle 4 enters the loop reactor 6 through the circulation pump 5.

[0045] The synthetic liquid is prepared by depolymerizing paraformaldehyde in a front-end process well known in the industry, followed by an addition reaction with glycine in the presence of methanol and triethylamine. The raw materials of the synthetic liquid contain 13 wt% glycine, 52 wt% methanol and 15 wt% triethylamine.

[0046] The preparation method of the synthetic liquid is as follows: the addition temperature is 35° C., the residence time is 40 minutes, and the insulation temperature is 40° C.

[0047] The feed rate of the dimethyl phosphite is 1720 kg / h;

[0048] The feed rate of the synthetic liquid is 7500 kg / h;

[0049] The feed rate of triethylamine in the triethylamine tank 2 is 50 kg / h.

[0050] The material temperature in the loop reactor 6 is 50°C; the material temperature in the esterification kettle 4 is 50°C.

[0051] The circulation flow rate of the circulation pump 5 is 3m 3 / h.

[0052] The pH value of the material in the esterification kettle 4 is maintained at 7.2.

[0053] The total flow rate of the material feed in the esterification kettle 4 is 10m 3 / h.

[0054] The material residence time in the esterification kettle 4 is 0.5 h.

[0055] Example 2

[0056] The specific implementation is the same as that of Example 1; the difference is that in Example 2:

[0057] The feed rate of the dimethyl phosphite is 1360 kg / h; the feed rate of the synthetic liquid is 6000 kg / h; and the feed rate of triethylamine in the triethylamine tank 2 is 40 kg / h.

[0058] The circulation flow rate of the circulation pump 5 is 2m 3 / h.

[0059] The pH value of the material in the esterification kettle 4 is maintained at 7.

[0060] The material residence time in the esterification kettle 4 is 40 minutes.

[0061] Comparative Example 1

[0062] The specific implementation is the same as in Example 1; except that, in Comparative Example 1:

[0063] The feed rate of the dimethyl phosphite is 1800 kg / h; the feed rate of the synthetic liquid is 8500 kg / h; and the feed rate of triethylamine in the triethylamine tank 2 is 40 kg / h.

[0064] The pH value of the material in the esterification kettle 4 is maintained at 7.5.

[0065] The material residence time in the esterification kettle 4 is 25 minutes.

[0066] Comparative Example 2

[0067] The specific implementation is the same as Example 1; except that, in Comparative Example 2, triethylamine was not added to the esterification kettle 4 through the triethylamine tank 2, and the pH value of the material in the esterification kettle 4 was maintained at 6.5.

[0068] Comparative Example 3

[0069] The specific implementation is the same as Example 1; except that, in Comparative Example 3, the loop reactor 6 is not used, dimethyl phosphite is added to the esterification kettle 4, and the pH value of the material in the esterification kettle 4 is maintained at 6.6.

[0070] Performance testing methods

[0071] The performance tests were carried out in the embodiments and comparative examples, and the test data are listed in Table 1.

[0072] Content Analysis: The test method follows GB / T 12686-2017. The sample was dissolved in water, using aqueous sodium hydroxide as the mobile phase. An ion chromatograph with a negative ion column and a conductivity detector was used to separate and determine the impurities N-methylglyphosate and glyphosate in the sample. The retention time of glyphosate was approximately 24 minutes. Phosphorus utilization rate = (mass of glyphosate × 31 / 169.01) / (mass of dimethyl phosphite × 31 / 110.05); glyphosate yield = (mass of solid glyphosate + mass of glyphosate in mother liquor) / theoretical glyphosate mass.

[0073] Performance test data

[0074] Table 1

[0075] Glyphosate yield% Glyphosate content% Glyphosate content% P utilization % Example 1 85.3 97.7 0.80 75.2 Example 2 85.1 97.3 0.82 75.1 Comparative Example 1 76.0 95.3 1.51 69.3 Comparative Example 2 76.3 95.1 1.62 68.2 Comparative Example 3 75.7 95.3 1.48 65.3

Claims

1. A device for continuously synthesizing glyphosate by the glycine method, characterized in that: include: A synthesis liquid tank (1), a triethylamine tank (2), a dimethyl phosphite tank (3), an esterification kettle (4), a circulation pump (5), a loop reactor (6), a synthesis liquid buffer kettle (7), an acidification system (8), a dealcoholization and deacidification system (9) and a crystallization centrifugal system (10). The synthesis liquid tank (1) and the triethylamine tank (2) are respectively connected to the esterification kettle (4), the dimethyl phosphite tank (3) is connected to the inlet of the loop reactor (6), the bottom of the esterification kettle (4) is connected to the circulation pump (5) and the inlet of the loop reactor (6), the outlet of the loop reactor (6) is connected to the inlet of the esterification kettle (4), and the esterification kettle (4), the acidification system (8), the dealcoholization and deacidification system (9) and the crystallization centrifugal system (10) are connected in sequence.

2. The device for continuously synthesizing glyphosate by the glycine method according to claim 1, characterized in that: The esterification kettle (4) is provided with an overflow port (11), and the overflow port (11) is connected to the synthetic liquid buffer kettle (7). The outlet of the loop reactor (6) enters the esterification kettle (4) through an extension pipe.

3. A production process for continuously synthesizing glyphosate by the glycine method according to the device of claim 2, characterized in that: The following steps are involved: S1, adding the synthetic liquid into the esterification kettle (4) through the synthetic liquid tank (1); S2, adding dimethyl phosphite through the dimethyl phosphite tank (3) from the inlet of the loop reactor (6) to the esterification kettle (4), and adding triethylamine through the triethylamine tank (2) to the esterification kettle (4), to carry out esterification reaction; S3, the material in the esterification kettle (4) overflows into the synthetic liquid buffer kettle (7) through the overflow port (11) to obtain the esterification liquid; S4, the esterified liquid passes through the acidification system (8), the dealcoholization and deacidification system (9) and the crystallization centrifugation system (10) in sequence to obtain glyphosate.

4. The production process for continuous synthesis of glyphosate by glycine method according to claim 3, characterized in that: The raw materials for preparing the synthetic liquid include a depolymerization product of paraformaldehyde, methanol, triethylamine and glycine.

5. The production process for continuous synthesis of glyphosate by glycine method according to claim 4, characterized in that: The mass ratio of dimethyl phosphite to the synthetic liquid in the esterification kettle (4) is (0.2-0.24):

1.

6. The production process of continuous synthesis of glyphosate by glycine method according to claim 5, characterized in that: The material temperature in the loop reactor (6) is 45-50°C; the material temperature in the esterification kettle (4) is 45-50°C.

7. The production process for continuous synthesis of glyphosate by the glycine method according to claim 6, characterized in that: The mass ratio of triethylamine and synthetic liquid added from the triethylamine tank (2) to the esterification kettle (4) is (0.006-0.007):

1.

8. The production process of continuous synthesis of glyphosate by glycine method according to claim 7, characterized in that: The circulation flow rate of the circulation pump (5) is 2-4m 3 / h.

9. The production process for continuous synthesis of glyphosate by the glycine method according to claim 8, characterized in that: The pH value of the material in the esterification kettle (4) is maintained at 7-8.

10. The production process of continuous synthesis of glyphosate by glycine method according to claim 9, characterized in that: The material residence time in the esterification kettle (4) is 0.5-1h.

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