Process for synthesizing pretilachlor through continuous acylation

Abstract

The invention relates to the technical field of pretilachlor synthesis, in particular to a process for synthesizing pretilachlor through continuous acylation, which at least comprises the following steps: conveying 2, 6-diethyl anilino propyl ether and chloroacetyl chloride into a microchannel reactor for reaction to generate a pretilachlor mixture; the pretilachlor product is prepared by sequentially carrying out flash evaporation treatment, high-temperature treatment, alkali washing treatment and dehydration on the pretilachlor mixture, and compared with a traditional production process, the process flow is simple, and efficient and environment-friendly continuous production of pretilachlor is realized.

Description

Technical Field

[0001] The invention relates to the technical field of pretilachlor synthesis, in particular to a process for synthesizing pretilachlor through continuous acylation. Background Art

[0002] Pretilachlor is a special herbicide for rice fields with high selectivity, which is safe for rice and has a wide spectrum of weed control. At present, the synthesis of pretilachlor mainly adopts intermittent acylation reaction, and the reaction process has a long reaction time, acid binding agents, organic solvents, etc. used in the process, which not only increases production costs, but also pollutes the environment. For example, Chinese patent (publication number is CN 117019049A) discloses a method and device for synthesizing pretilachlor by continuous acylation, although continuous acylation reaction is achieved to a certain extent, the device is complicated, the operation is inconvenient, and it is necessary to preheat the safety agent with an electric heating tube, and the energy consumption is high, which is not suitable for large-scale industrial promotion and application. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a process for synthesizing pretilachlor by continuous acylation. Compared with the traditional production process, the process flow is simple and the efficient and environmentally friendly continuous production of pretilachlor is realized.

[0004] The invention provides a process for synthesizing pretilachlor by continuous acylation, which comprises at least the following steps: transporting 2,6-diethylanilinopropyl ether and chloroacetyl chloride to a microchannel reactor for reaction to generate a pretilachlor mixture; and sequentially subjecting the pretilachlor mixture to flash treatment, high temperature treatment, and alkali washing treatment, and dehydrating to obtain a pretilachlor product.

[0005] As a preferred technical solution, the molar ratio of 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:(1.05-1.5), preferably 1:(1.2-1.4).

[0006] As a preferred technical solution, the reaction temperature in the microchannel reactor is 30-90° C. and the reaction time is 0.5-3 min.

[0007] Preferably, the reaction temperature in the microchannel reactor is 40-60° C. and the reaction time is 1-2 min.

[0008] Preferably, the reaction temperature in the microchannel reactor is 50-60° C. and the reaction time is 1.5-2 min.

[0009] As a preferred technical solution, the flash treatment includes: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to 60-90 kPa for flash evaporation, the flashed hydrogen chloride enters an absorption tower to be absorbed as hydrochloric acid for repeated utilization, and the pretilachlor mixture after flash evaporation is subjected to high-temperature treatment.

[0010] Preferably, the flash treatment comprises: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to 70-80 kPa for flash evaporation, allowing the flashed hydrogen chloride to enter an absorption tower to be absorbed as hydrochloric acid for repeated utilization, and subjecting the pretilachlor mixture after the flash treatment to high-temperature treatment.

[0011] As a preferred technical solution, the high-temperature treatment includes: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 50-110°C and the pressure to 10-70 kPa to evaporate and recover excess chloroacetyl chloride, and subjecting the high-temperature-treated pretilachlor mixture to alkaline washing.

[0012] Preferably, the high temperature treatment comprises: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 70-80°C and the pressure to 30-50 kPa to evaporate and recover excess chloroacetyl chloride, and subjecting the high temperature-treated pretilachlor mixture to alkaline washing.

[0013] As a preferred technical solution, the alkaline washing treatment comprises: washing the pretilachlor mixture after high temperature treatment with an alkaline aqueous solution with a mass concentration of 0.5-2%.

[0014] Preferably, the mass concentration of the alkaline aqueous solution is 0.8-1.5%.

[0015] Preferably, the alkaline aqueous solution is a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution.

[0016] The continuous synthesis process provided by the present invention controls the molar ratio of 2,6-diethylanilinopropyl ether and chloroacetyl chloride and adopts a microchannel reactor to react, thereby shortening the reaction time, eliminating the acid binding agent (sodium carbonate, potassium carbonate), reducing the production cost, reducing environmental pollution, and achieving high conversion rate and high purity of the pretilachlor product. In particular, the pretilachlor mixture is designed to be flash treated, high-temperature treated, and alkaline washed in sequence, and the treatment conditions are controlled to achieve the recycling and reuse of the byproduct hydrogen chloride and the recycling and reuse of the excess chloroacetyl chloride, and to ensure the high conversion rate and high purity of the pretilachlor product.

[0017] The process for the continuous acylation synthesis of pretilachlor provided by the present invention does not require the use of a solvent, saves the energy consumption of desolventizing compared with an intermittent process, has significant technical advantages and economic value, and is expected to promote the further development of pretilachlor synthesis technology.

[0018] Beneficial Effects

[0019] 1. The present invention provides a process for the continuous acylation synthesis of pretilachlor. Compared with the traditional production process, the process flow is simple and the efficient and environmentally friendly continuous production of pretilachlor is realized.

[0020] 2. The continuous synthesis process provided by the present invention controls the molar ratio of 2,6-diethylanilinopropyl ether and chloroacetyl chloride and adopts a microchannel reactor to react, thereby shortening the reaction time, eliminating the acid-binding agent (sodium carbonate, potassium carbonate), reducing the production cost, reducing environmental pollution, and achieving a high conversion rate of the pretilachlor product and a high product purity.

[0021] 3. The present invention is designed to sequentially subject the pretilachlor mixture to flash treatment, high temperature treatment, and alkaline washing treatment, and coordinates the control of treatment conditions, thereby achieving the recovery and reuse of the by-product hydrogen chloride and the recovery and reuse of excess chloroacetyl chloride, and ensuring the high conversion rate and high purity of the pretilachlor product.

[0022] 4. The continuous acylation process for synthesizing pretilachlor provided by the present invention does not require the use of solvents, and saves the energy consumption of desolventizing compared with the intermittent process. It has significant technical advantages and economic value, and is expected to promote the further development of pretilachlor synthesis technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the process flow for the continuous acylation synthesis of pretilachlor provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] Example 1

[0025] See also Figure 1 Embodiment 1 of the present invention provides a process for continuously acylating and synthesizing pretilachlor, comprising the following steps: transporting 2,6-diethylanilinopropyl ether and chloroacetyl chloride to a microchannel reactor for reaction to generate a pretilachlor mixture; subjecting the pretilachlor mixture to flash treatment, high temperature treatment, and alkali washing treatment in sequence, and dehydrating to obtain a pretilachlor product.

[0026] The molar ratio of the 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.2.

[0027] The reaction temperature in the microchannel reactor is 50° C. and the reaction time is 2 min.

[0028] The flash treatment comprises: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to 75 kPa for flash evaporation (hydrogen chloride removal rate is 97%), the flashed hydrogen chloride enters an absorption tower to be absorbed as hydrochloric acid for repeated use, and the pretilachlor mixture after the flash treatment is subjected to high temperature treatment.

[0029] The high temperature treatment includes: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 70°C and the pressure to 31 kPa to evaporate and recover excess chloroacetyl chloride (recovery rate 90%), and performing alkali washing on the high temperature-treated pretilachlor mixture.

[0030] The alkaline washing treatment comprises: washing the high-temperature treated pretilachlor mixture with a sodium hydroxide aqueous solution having a mass concentration of 1%.

[0031] Example 2

[0032] Embodiment 2 of the present invention provides a process for the continuous acylation synthesis of pretilachlor, comprising the following steps: transporting 2,6-diethylanilinopropyl ether and chloroacetyl chloride to a microchannel reactor for reaction to generate a pretilachlor mixture; subjecting the pretilachlor mixture to flash treatment, high temperature treatment, and alkaline washing treatment in sequence, and dehydrating to obtain a pretilachlor product.

[0033] The molar ratio of the 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.4.

[0034] The reaction temperature in the microchannel reactor is 60° C. and the reaction time is 1.5 min.

[0035] The flash treatment comprises: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to 72 kPa for flash evaporation (hydrogen chloride removal rate is 98%), the flashed hydrogen chloride enters an absorption tower to be absorbed as hydrochloric acid for repeated use, and the pretilachlor mixture after the flash treatment is subjected to high temperature treatment.

[0036] The high temperature treatment includes: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 80° C. and the pressure to 45 kPa to evaporate and recover excess chloroacetyl chloride (recovery rate 91%), and performing alkali washing on the high temperature-treated pretilachlor mixture.

[0037] The alkaline washing treatment comprises: washing the high-temperature treated pretilachlor mixture with a sodium hydroxide aqueous solution having a mass concentration of 1%.

[0038] Example 3

[0039] Example 3 of the present invention provides a process for the continuous acylation synthesis of pretilachlor, comprising the following steps: transporting 2,6-diethylanilinopropyl ether and chloroacetyl chloride to a microchannel reactor for reaction to generate a pretilachlor mixture; subjecting the pretilachlor mixture to flash treatment, high temperature treatment, and alkaline washing treatment in sequence, and dehydrating to obtain a pretilachlor product.

[0040] The molar ratio of the 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.3.

[0041] The reaction temperature in the microchannel reactor is 60° C. and the reaction time is 1.5 min.

[0042] The flash treatment comprises: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to 72 kPa for flash evaporation (hydrogen chloride removal rate is 98%), the flashed hydrogen chloride enters an absorption tower to be absorbed as hydrochloric acid for repeated use, and the pretilachlor mixture after the flash treatment is subjected to high temperature treatment.

[0043] The high temperature treatment comprises: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 80° C. and the pressure to 45 kPa to evaporate and recover excess chloroacetyl chloride (recovery rate 90%), and performing alkali washing on the high temperature-treated pretilachlor mixture.

[0044] The alkaline washing treatment comprises: washing the high-temperature treated pretilachlor mixture with a sodium hydroxide aqueous solution having a mass concentration of 1%.

[0045] Example 4

[0046] Embodiment 4 of the present invention provides a process for the continuous acylation synthesis of pretilachlor, comprising the following steps: transporting 2,6-diethylanilinopropyl ether and chloroacetyl chloride to a microchannel reactor for reaction to generate a pretilachlor mixture; subjecting the pretilachlor mixture to flash treatment, high temperature treatment, and alkaline washing treatment in sequence, and dehydrating to obtain a pretilachlor product.

[0047] The molar ratio of the 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.05.

[0048] The reaction temperature in the microchannel reactor is 50° C. and the reaction time is 2 min.

[0049] The flash treatment comprises: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to 75 kPa for flash evaporation (hydrogen chloride removal rate is 97%), the flashed hydrogen chloride enters an absorption tower to be absorbed as hydrochloric acid for repeated use, and the pretilachlor mixture after the flash treatment is subjected to high temperature treatment.

[0050] The high temperature treatment includes: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 70°C and the pressure to 31 kPa to evaporate and recover excess chloroacetyl chloride (recovery rate 80%), and performing alkali washing on the high temperature-treated pretilachlor mixture.

[0051] The alkaline washing treatment comprises: washing the high-temperature treated pretilachlor mixture with a sodium hydroxide aqueous solution having a mass concentration of 1%.

[0052] Example 5

[0053] Example 5 of the present invention provides a process for the continuous acylation synthesis of pretilachlor, comprising the following steps: transporting 2,6-diethylanilinopropyl ether and chloroacetyl chloride to a microchannel reactor for reaction to generate a pretilachlor mixture; subjecting the pretilachlor mixture to flash treatment, high temperature treatment, and alkaline washing treatment in sequence, and dehydrating to obtain a pretilachlor product.

[0054] The molar ratio of the 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.25.

[0055] The reaction temperature in the microchannel reactor is 60° C. and the reaction time is 1.5 min.

[0056] The flash treatment comprises: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to be 100 kPa for flash evaporation (hydrogen chloride removal rate is 72%), the flashed hydrogen chloride enters an absorption tower to be absorbed as hydrochloric acid for repeated use, and the pretilachlor mixture after the flash treatment is subjected to high temperature treatment.

[0057] The high temperature treatment includes: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 70°C and the pressure to 31 kPa to evaporate and recover excess chloroacetyl chloride (recovery rate 80%), and performing alkali washing on the high temperature-treated pretilachlor mixture.

[0058] The alkaline washing treatment comprises: washing the high-temperature treated pretilachlor mixture with a sodium hydroxide aqueous solution having a mass concentration of 1%.

[0059] Example 6

[0060] Example 6 of the present invention provides a process for the continuous acylation synthesis of pretilachlor, comprising the following steps: transporting 2,6-diethylanilinopropyl ether and chloroacetyl chloride to a microchannel reactor for reaction to generate a pretilachlor mixture; subjecting the pretilachlor mixture to flash treatment, high temperature treatment, and alkaline washing treatment in sequence, and dehydrating to obtain a pretilachlor product.

[0061] The molar ratio of the 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.3.

[0062] The reaction temperature in the microchannel reactor is 60° C. and the reaction time is 1.5 min.

[0063] The flash treatment comprises: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to 72 kPa for flash evaporation (hydrogen chloride removal rate is 98%), the flashed hydrogen chloride enters an absorption tower to be absorbed as hydrochloric acid for repeated use, and the pretilachlor mixture after the flash treatment is subjected to high temperature treatment.

[0064] The high temperature treatment comprises: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 70° C. and the pressure to 8 kPa to evaporate and recover excess chloroacetyl chloride (recovery rate 65%), and performing alkali washing on the high temperature-treated pretilachlor mixture.

[0065] The alkaline washing treatment comprises: washing the high-temperature treated pretilachlor mixture with a sodium hydroxide aqueous solution having a mass concentration of 1%.

[0066] Comparative Example 1

[0067] Comparative Example 1 of the present invention provides a process for synthesizing pretilachlor by acylation, comprising the following steps: a quantitative amount of 600 kg of 2,6-diethylanilinopropyl ether, 1800 kg of toluene, and 170 kg of sodium carbonate are put into a reactor, the temperature is lowered to 10° C., 300 kg of chloroacetyl chloride (the molar ratio of 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.04) is started to be added dropwise, the reaction temperature is maintained at <50° C. (the dropping speed is controlled according to the reaction temperature, and the reaction takes 4.5 hours), and after the reaction is completed, the pretilachlor product is obtained by washing with water to separate the salt water, washing with water to separate the water, and then desolventizing.

[0068] Comparative Example 2

[0069] Comparative Example 2 of the present invention provides a process for synthesizing pretilachlor by acylation, comprising the following steps: a quantitative amount of 600 kg of 2,6-diethylanilinopropyl ether, 1800 kg of toluene, and 170 kg of sodium carbonate are put into a reactor, the temperature is lowered to 10° C., 311 kg of chloroacetyl chloride (the molar ratio of 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.08) is started to be added dropwise, the temperature is maintained at <50° C. (the dropping speed is controlled according to the reaction temperature, and the reaction takes 4.5 hours), and after the reaction is completed, the pretilachlor product is obtained by washing with water to separate the salt water, washing with water to separate the water, and then desolventizing.

[0070] Comparative Example 3

[0071] Comparative Example 3 of the present invention provides a process for synthesizing pretilachlor by acylation, comprising the following steps: a quantitative amount of 600 kg of 2,6-diethylanilinopropyl ether, 1800 kg of toluene, and 170 kg of sodium carbonate are put into a reactor, the temperature is lowered to 10°C, 300 kg of chloroacetyl chloride (the molar ratio of 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:1.04) is started to be added dropwise, the temperature is maintained at <40°C (the dropping speed is controlled according to the reaction temperature, and the reaction takes 5 hours), and after the reaction is completed, the pretilachlor product is obtained by washing with water to separate the salt water, washing with water to separate the water, and then desolventizing.

[0072] Performance Testing

[0073] The conversion rates of the pretilachlor products provided in the examples and comparative examples were calculated based on 2,6-diethylanilinopropyl ether, and the purity of the pretilachlor products provided in Examples 1-13 was tested (GCMS area normalization method). The test results are shown in Table 1.

[0074] Table 1

[0075] Example Conversion rate / % purity / % Example 1 99.0 98.1 Example 2 99.2 98.2 Example 3 98.9 97.9 Example 4 90.0 89.1 Example 5 99.0 97.5 Example 6 98.9 97.9 Comparative Example 1 99.0 97.5 Comparative Example 2 99.5 97.8 Comparative Example 3 99.1 97.2

Claims

1. A process for synthesizing pretilachlor by continuous acylation, characterized in that: The method comprises at least the following steps: transporting 2,6-diethylanilinopropyl ether and chloroacetyl chloride to a microchannel reactor for reaction to generate a pretilachlor mixture; subjecting the pretilachlor mixture to flash evaporation treatment, high temperature treatment, alkali washing treatment in sequence, and dehydrating to obtain a pretilachlor product.

2. The process for synthesizing pretilachlor by continuous acylation according to claim 1, characterized in that: The molar ratio of the 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:(1.05-1.5).

3. A process for the continuous acylation synthesis of pretilachlor according to claim 2, characterized in that: The molar ratio of the 2,6-diethylanilinopropyl ether to chloroacetyl chloride is 1:(1.2-1.4).

4. The process for synthesizing pretilachlor by continuous acylation according to claim 1, characterized in that: The reaction temperature in the microchannel reactor is 30-90° C. and the reaction time is 0.5-3 min.

5. A process for the continuous acylation synthesis of pretilachlor according to claim 4, characterized in that: The reaction temperature in the microchannel reactor is 40-60° C. and the reaction time is 1-2 min.

6. The process for synthesizing pretilachlor by continuous acylation according to claim 1, characterized in that: The flash treatment comprises: conveying the pretilachlor mixture to a flash evaporator, controlling the flash pressure to be 60-90 kPa for flash evaporation, the flashed hydrogen chloride enters an absorption tower to be absorbed as hydrochloric acid for repeated utilization, and the pretilachlor mixture after the flash treatment is subjected to high temperature treatment.

7. The process for synthesizing pretilachlor by continuous acylation according to claim 1, characterized in that: The high temperature treatment comprises: conveying the flash-treated pretilachlor mixture to a scraper evaporator, controlling the evaporation temperature to 50-110° C. and the pressure to 10-70 kPa to evaporate and recover excess chloroacetyl chloride, and performing alkaline washing on the high temperature-treated pretilachlor mixture.

8. The process for synthesizing pretilachlor by continuous acylation according to claim 1, characterized in that: The alkaline washing treatment comprises: washing the high-temperature treated pretilachlor mixture with an alkaline aqueous solution having a mass concentration of 0.5-2%.

9. The process for synthesizing pretilachlor by continuous acylation according to claim 8, characterized in that: The mass concentration of the alkaline aqueous solution is 0.8-1.5%.

10. The process for synthesizing pretilachlor by continuous acylation according to claim 8, characterized in that: The alkaline aqueous solution is a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution.

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