Propanil and preparation method thereof

Abstract

The invention provides propanil and a preparation method thereof, and the preparation method comprises the following steps: (1) carrying out synthesis treatment on a raw material system comprising 3, 4-dichloroaniline, propionic acid, xylene and water until the mass percentage content of free amine in the raw material system is not higher than 0.5% to obtain a synthetic solution; (2) carrying out separation and purification treatment on the synthetic liquid until the mass percentage content of propionic acid in the synthetic liquid is not higher than 0.5%, so as to obtain propanil of which the liquid chromatogram content is not lower than 98%; according to the preparation method, propanil can be synthesized in one step without introducing a catalyst, raw materials are simple and easy to obtain, the reaction process is simple, and industrialization is easy to achieve; through synergistic matching of raw material systems, the product yield is greatly improved, raw materials are saved, the cost is easy to control, and after separation and purification, a propanil product with the liquid chromatogram content not lower than 98% can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticide synthesis, and particularly relates to propanil and a preparation method thereof. Background Art

[0002] Propanil is a highly selective contact herbicide of the amide class. It is mainly used in rice paddies or direct-seeding fields. It is a specific drug for controlling barnyard grass. It can also be used to control a variety of other grass and dicotyledonous weeds, such as duckweed, water celery, crabgrass, and foxtail grass. Propanil is almost not transported in the plant body and only works at the contact site of the agent. Its mechanism of action is multifaceted. It not only destroys the photosynthesis of plants, but also inhibits respiration and oxidative phosphorylation, interferes with nucleic acid and protein synthesis, etc. As a result, the physiological functions of sensitive plants are affected, water loss is accelerated, leaves gradually dry up, and finally die. Since rice has 20 times greater ability to degrade propanil than barnyard grass, propanil can be quickly decomposed into non-toxic substances by hydrolases in the rice body, so propanil is safe for rice.

[0003] At present, there are two main methods for synthesizing propanil. One is a one-step synthesis method, which is to heat the solvent chlorobenzene, 3,4-dichloroaniline, propionic acid and catalyst until the materials are completely dissolved, and then slowly add phosphorus trichloride to obtain a synthetic liquid, and then the synthetic liquid is separated, purified and purified to prepare the propanil product. Although this method can synthesize propanil in one step, due to the use of a catalyst, the propanil product contains more impurities, which affects the content and use effect of the propanil product.

[0004] Another method is a multi-step synthesis method, in which chlorobenzene is first acylated with propionyl chloride to generate p-chlorophenylacetone, which is then condensed with hydroxylamine hydrochloride to generate 1-(4-chlorophenyl)-1-acetone oxime, which is then rearranged under acidic conditions and finally chlorinated to obtain the propanil product. This method has many steps, the process is too complicated, the industrialization is difficult, and the process cost is high.

[0005] Therefore, it is urgent to develop a preparation method with simple process that can further improve the content and yield of propanil product. Summary of the invention

[0006] The invention provides a method for preparing propanil, which is used to solve the problems in the prior art that the preparation method is complicated and the content and yield of the prepared propanil product are low.

[0007] The present invention also provides a propanil, which is prepared by the above preparation method and can obtain a propanil product with a liquid chromatography content of not less than 98%.

[0008] In one aspect, the present invention provides a method for preparing propanil, comprising the following steps: (1) subjecting a raw material system comprising 3,4-dichloroaniline, propionic acid, xylene and water to a synthesis treatment until the mass percentage of free amine in the raw material system is no more than 0.5%, thereby obtaining a synthetic liquid; (2) The synthetic liquid is separated and purified until the mass percentage of the propionic acid in the synthetic liquid is no more than 0.5%, and the liquid chromatography content of the propanil is no less than 98%.

[0009] Furthermore, the xylene is o-xylene.

[0010] Furthermore, the xylene includes meta-xylene, para-xylene and o-xylene in a mass ratio of (45-70):(15-25):(10-15).

[0011] Furthermore, the mass percentage of water in the raw material system is 1-2%.

[0012] Furthermore, the mass ratio of the 3,4-dichloroaniline, the propionic acid and the xylene is 1:(0.72-1):(0.5-0.8).

[0013] Furthermore, the temperature of the synthesis treatment is 130-150°C.

[0014] Furthermore, step (1) further comprises: sequentially performing condensation reflux treatment and water separation treatment on the gas phase azeotrope obtained by the synthesis treatment.

[0015] Furthermore, the separation and purification process includes a reduced pressure distillation process.

[0016] Furthermore, the vacuum degree of the reduced pressure distillation treatment is -0.090~-0.1MPA, and the temperature is 100~130°C.

[0017] On the other hand, the present invention provides a propanil prepared by the above-mentioned preparation method, wherein the liquid chromatography content of the propanil is not less than 98%.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: the preparation method provided by the present invention can synthesize propanil in one step by subjecting a raw material system including 3,4-dichloroaniline, propionic acid, xylene and water to a synthetic treatment without introducing a catalyst, the raw materials are simple and easy to obtain, and the reaction process is simple and easy to realize industrialization; through the coordinated matching of the raw material system, the product yield is greatly improved, the raw materials are saved, the cost is easy to control, and after separation and purification, a propanil product with a liquid chromatography content of not less than 98% can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a test spectrum of propanil content prepared in Example 1 of the present invention; Figure 2 This is a test spectrum of propanil content prepared in Example 2 of the present invention; Figure 3 This is a test spectrum of propanil content prepared in Example 3 of the present invention; Figure 4 This is the test spectrum of the propanil content prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In one aspect, the present invention provides a method for preparing propanil, comprising the following steps: (1) subjecting a raw material system comprising 3,4-dichloroaniline, propionic acid, xylene and water to a synthesis treatment until the mass percentage of free amine in the raw material system is no more than 0.5%, thereby obtaining a synthetic liquid; (2) separating and purifying the synthetic liquid until the mass percentage of propionic acid in the synthetic liquid is no more than 0.5%, and obtaining a liquid chromatography content of propanil of no less than 98%.

[0022] It should be noted that the propanil in the method for preparing propanil provided by the present invention refers to a propanil product that can be used for sale, rather than a pure compound. Therefore, the above-mentioned propanil may contain trace impurities.

[0023] Among them, the mass percentage of free amine in the raw material system is measured in accordance with the provisions of Q / TQSY 02.10-2024.

[0024] The mass percentage of propionic acid in the synthetic liquid is measured according to the indicator method of GB / T28135-201 Pesticide Acid (Alkalinity) Test Method.

[0025] The liquid chromatography content of propanil was measured in accordance with the provisions of Q / TQSY 02.10-2024. The instrument used was a high performance liquid chromatograph (Shimadzu), wherein the chromatographic column was C18-250mm, the mobile phase was methanol-water solution (the mass ratio of methanol to water was 8:2); the flow rate was 1.0 ml / min, and the column temperature was 30°C.

[0026] In step (1), the present invention uses a raw material system including 3,4-dichloroaniline, propionic acid, xylene and water for synthesis treatment. Since free amine can be separated from 3,4-dichloroaniline in the raw material system, when the mass percentage of free amine in the raw material system is not higher than 0.5%, that is, most of the raw material 3,4-dichloroaniline has been converted into propanil, the synthesis treatment is terminated at this time to obtain a synthetic liquid.

[0027] It can be understood that the main component of the synthetic liquid at this time is pure propanil, and includes trace amounts of 3,4-dichloroaniline, propionic acid, and a mixture of xylene and water; therefore, through the separation and purification treatment in step (2), when the mass percentage of propionic acid in the synthetic liquid is not higher than 0.5%, a propanil product with a liquid chromatography content of not less than 98% can be obtained.

[0028] Among them, 3,4-dichloroaniline and propionic acid are used as raw materials for preparing propanil to undergo a synthetic reaction to generate propanil and water, and the inventors have found that using xylene and water as solvents to participate in the synthetic process can promote the forward progress of the synthetic reaction, greatly improve the conversion rate of the synthetic reaction, improve the utilization rate of the raw materials and the product yield, and make the prepared propanil have a higher purity. Among them, the synthetic reaction equation is shown in formula (1).

[0029]

[0030] The preparation method provided by the present invention can synthesize propanil in one step without introducing a catalyst by subjecting a raw material system including 3,4-dichloroaniline, propionic acid, xylene and water to synthetic treatment, and the raw materials are simple and easy to obtain, and the reaction process is simple and easy to realize industrialization; through the coordinated matching of the raw material system, the product yield is greatly improved, the raw materials are saved, the cost is easy to control, and after separation and purification, a propanil product with a liquid chromatography content of not less than 98% can be obtained.

[0031] The present invention does not limit the equipment for the synthesis process, and any equipment that can mix the raw material system and cause a synthesis reaction can be used; in a specific embodiment, the equipment for the synthesis process adopts a reactor; further, the reactor is a steel-lined enamel reactor.

[0032] The synthesis process can also be terminated by judging that no water is further generated during the synthesis process and the mass percentage of bound free amine in the raw material system is not higher than 0.5%.

[0033] Furthermore, the xylene is o-xylene.

[0034] The present invention uses xylene as a solvent for the synthesis process. The inventors have found that when o-xylene is used as the xylene, the synergistic effect of the raw material system can be further improved, the reaction yield can be further improved, and the content of the obtained propanil product can be increased.

[0035] In a specific embodiment, xylene includes meta-xylene, para-xylene and o-xylene in a mass ratio of (45-70):(15-25):(10-15).

[0036] When the xylene used in the present invention includes m-xylene, p-xylene and o-xylene in a mass ratio of (45-70): (15-25): (10-15), the raw material cost can be further reduced, the synergistic effect of the raw material system can be improved, the reaction yield can be further improved, and the content of the obtained propanil product can be increased.

[0037] Optionally, the mass percentage of water in the raw material system is 1-2%.

[0038] By further limiting the water content in the raw material system, the reaction yield can be further improved, the content of the obtained propanil product can be increased, and the subsequent separation energy consumption can be further reduced.

[0039] Furthermore, the mass ratio of 3,4-dichloroaniline, propionic acid and xylene is 1:(0.72~1):(0.5~0.8).

[0040] In a specific embodiment, the content of 3,4-dichloroaniline is not less than 99.5%, and the content of propionic acid is not less than 99%; by further limiting the mass ratio of 3,4-dichloroaniline, propionic acid and xylene in the raw material system, the progress of the synthesis reaction can be further controlled, the raw materials can be further saved, the reaction yield can be further improved, and the content of the obtained propanil product can be increased.

[0041] The temperature of the synthesis process is 130-150°C.

[0042] It can be understood that a certain temperature is required to make the raw material system undergo a synthesis reaction, which can further promote uniform mixing of the raw material system, further save raw materials, improve reaction yield, and increase the content of the obtained propanil product.

[0043] Specifically, step (1) further comprises: sequentially performing condensation reflux treatment and water separation treatment on the gas phase azeotrope obtained by the synthesis treatment.

[0044] It can be understood that when the temperature of the synthesis treatment is 130~150°C, while the raw material system undergoes a synthesis reaction to generate pure propanil and water, part of the propionic acid, xylene and water therein will undergo azeotropy to form a gas-phase azeotrope. The gas-phase azeotrope needs to be condensed and refluxed so that it can re-enter the raw material system to participate in the synthesis treatment, which can further save raw materials and improve the yield of the product. Since the product of the synthesis reaction also includes water, the azeotrope after condensation and reflux is separated to remove excess water, further promote the forward progress of the synthesis reaction, further save raw materials, and improve the yield and content of the product.

[0045] In a specific embodiment, the separation and purification process comprises a reduced pressure distillation process.

[0046] By separating and purifying the synthetic liquid through vacuum distillation, the occurrence of side reactions can be further reduced, the content of the product can be increased, and the energy consumption of the separation and purification process can be further reduced, thereby reducing costs.

[0047] Furthermore, the vacuum degree of the reduced pressure distillation treatment is -0.090~-0.1MPA, and the temperature is 100~130°C.

[0048] By further limiting the vacuum degree and treatment temperature of the reduced pressure distillation treatment, the energy consumption of the separation and purification treatment can be further reduced, the cost can be reduced, and the content and yield of propanil obtained by the separation and purification treatment can be further improved.

[0049] On the other hand, the present invention provides propanil, which is prepared by the above-mentioned preparation method, and the liquid chromatography content of propanil is not less than 98%.

[0050] The above-mentioned propanil refers to the propanil product that can be used for sale, rather than the pure compound. Therefore, the above-mentioned propanil may contain trace amounts of impurities.

[0051] The liquid phase chromatographic content of the propanil provided by the invention is not less than 98%, and has excellent purity and yield.

[0052] Hereinafter, a preparation method of propanil provided by the present invention is introduced in detail through specific examples. Example 1

[0053] The preparation method of propanil used in this embodiment comprises the following steps: (1) adding a raw material system including 375 kg of 3,4-dichloroaniline, 270 kg of propionic acid, 190 kg of xylene and 11.25 kg of water (accounting for 1.33% by mass in the raw material system) into a reaction kettle at once, stirring evenly and heating to 140° C. for synthesis treatment to obtain a gas phase azeotrope; Wherein, xylene includes m-xylene, p-xylene and o-xylene in a mass ratio of 50:20:15; (2) After the gas phase azeotrope is subjected to condensation and reflux treatment, it is subjected to water separation treatment through a water separator; until the temperature of the reactor is raised to 150° C., the mass percentage of free amine in the raw material system is 0.5%, and there is no water in the water separator, the synthesis treatment is terminated to obtain a synthetic liquid; (3) The synthetic liquid is subjected to reduced pressure distillation at -0.095 MPa and 120° C. until the mass percentage of propionic acid in the synthetic liquid is no more than 0.5%, thereby obtaining propanil. Example 2

[0054] The difference between this embodiment and embodiment 1 is that in step (1), the raw material system includes 375 kg of 3,4-dichloroaniline, 300 kg of propionic acid, 250 kg of xylene, and 11.25 kg of water (accounting for 1.2% by mass in the raw material system). Example 3

[0055] The difference between this embodiment and embodiment 1 is that in step (1), the raw material system includes 375 kg of 3,4-dichloroaniline, 375 kg of propionic acid, 300 kg of xylene, and 11.25 kg of water (accounting for 1.06% by mass in the raw material system). Example 4

[0056] The difference between this embodiment and embodiment 1 is that in step (1), the raw material system includes 375 kg of 3,4-dichloroaniline, 320 kg of propionic acid, 280 kg of xylene, and 11.25 kg of water (accounting for 1.14% by mass in the raw material system). Example 5

[0057] The difference between this embodiment and embodiment 1 is that in step (1), the amount of xylene added to the raw material system is 180 kg. Example 6

[0058] The difference between this embodiment and embodiment 1 is that in step (1), the amount of xylene added to the raw material system is 310 kg. Example 7

[0059] The difference between this embodiment and embodiment 1 is that in step (1), the amount of propionic acid added to the raw material system is 265 kg. Example 8

[0060] The difference between this embodiment and embodiment 1 is that in step (1), the amount of propionic acid added to the raw material system is 340 kg. Example 9

[0061] The difference between this embodiment and embodiment 1 is that in step (1), the amount of water added to the raw material system is 8 kg (accounting for 0.95% of the mass percentage in the raw material system). Example 10

[0062] The difference between this embodiment and embodiment 1 is that in step (1), the xylene in the raw material system is p-xylene. Embodiment 11

[0063] The difference between this embodiment and embodiment 1 is that in step (1), the xylene in the raw material system is o-xylene. Example 12

[0064] The difference between this embodiment and embodiment 1 is that in step (1), the temperature of the synthesis treatment is 125°C. Example 13

[0065] The difference between this embodiment and embodiment 1 is that in step (1), the temperature of the synthesis treatment is 155°C.

[0066] Embodiment 14

[0067] The difference between this embodiment and embodiment 1 is that in step (3), the vacuum degree of the reduced pressure distillation treatment is -0.08 MPa.

[0068] Embodiment 15

[0069] The difference between this embodiment and embodiment 1 is that in step (3), the temperature of the reduced pressure distillation treatment is 90°C.

[0070] Example 16

[0071] The difference between this embodiment and embodiment 1 is that in step (1), the amount of water added to the raw material system is 25 kg (accounting for 2.91% of the mass percentage in the raw material system).

[0072] Comparative Example 1 The difference between this comparative example and Example 1 is that in step (1), xylene is not included in the raw material system.

[0073] Comparative Example 2 The difference between this comparative example and Example 1 is that in step (1), the raw material system does not include water.

[0074] Test Example 1 The propanil prepared in the above examples and comparative examples was tested.

[0075] Among them, the content of propanil was measured in accordance with the provisions of Q / TQSY 02.10-2024. The instrument used was a high performance liquid chromatograph (Shimadzu), in which the chromatographic column was C18-250mm, and the mobile phase was methanol-water solution (the mass ratio of methanol to water was 8:2); the flow rate was 1.0ml / min, and the column temperature was 30°C.

[0076] Among them, the HPLC test results of Examples 1 to 4 are as follows: Figures 1 to 4 , as shown in Tables 1 to 4; Table 1 HPLC test results of the product of Example 1

[0077] Table 2 HPLC test results of the product of Example 2

[0078] Table 3 HPLC test results of the product of Example 3

[0079] Table 4 HPLC test results of the product of Example 4

[0080] The yield is calculated by the following formula:

[0081] The test results are shown in Table 5.

[0082] Table 5 Product yields of Examples 1-16 and Comparative Examples 1-2

[0083] As can be seen from the table, in the embodiment, by using 3,4-dichloroaniline as the main synthetic raw material, propionic acid as both the raw material and the solvent, and xylene and water as co-solvents for synthesis treatment, propanil can be synthesized in one step without introducing a catalyst, the raw materials are simple and easy to obtain, and the reaction process is simple and easy to realize industrialization; through the coordinated combination of the raw material system, the yield of the propanil product can be as high as 99.95%, while saving raw materials, the cost is easy to control, and after separation and purification, a propanil product with a liquid chromatography content of up to 99.58% can be obtained.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. If these modifications and variations fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the protection scope of the present invention.

Claims

1. A method for preparing propanil, characterized in that: The following steps are involved: (1) subjecting a raw material system comprising 3,4-dichloroaniline, propionic acid, xylene and water to a synthesis treatment until the mass percentage of free amine in the raw material system is no more than 0.5%, thereby obtaining a synthetic liquid; (2) The synthetic liquid is separated and purified until the mass percentage of the propionic acid in the synthetic liquid is no more than 0.5%, and the liquid chromatography content of the propanil is no less than 98%.

2. The method for preparing propanil according to claim 1, characterized in that: The xylene is o-xylene.

3. The method for preparing propanil according to claim 1, characterized in that: The xylene includes meta-xylene, para-xylene and o-xylene in a mass ratio of (45-70):(15-25):(10-15).

4. The method for preparing propanil according to claim 1, characterized in that: The mass percentage of the water in the raw material system is 1-2%.

5. The method for preparing propanil according to claim 1, characterized in that: The mass ratio of the 3,4-dichloroaniline, the propionic acid and the xylene is 1:(0.72-1):(0.5-0.8).

6. The method for preparing propanil according to any one of claims 1 to 5, characterized in that: The temperature of the synthesis treatment is 130-150°C.

7. The preparation method according to claim 6, characterized in that: Step (1) also includes: sequentially performing condensation reflux treatment and water separation treatment on the gas phase azeotrope obtained by the synthesis treatment.

8. The method for preparing propanil according to claim 7, characterized in that: The separation and purification process includes a reduced pressure distillation process.

9. The method for preparing propanil according to claim 8, characterized in that: The vacuum degree of the reduced pressure distillation treatment is -0.090~-0.1MPA, and the temperature is 100~130°C.

10. A propanil prepared by the method for preparing propanil according to any one of claims 1 to 9, characterized in that: The liquid chromatography content of the propanil is not less than 98%.

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