Clethodim amine salt, and preparation method therefor and use thereof

Abstract

A clethodim amine salt, and a preparation method therefor and the use thereof. The clethodim amine salt is a clethodim tert-butylamine salt, the chemical structural formula thereof being as follows: formula (1). The prepared clethodim tert-butylamine salt has good stability, and also has a herbicidal activity which is not weaker than that of clethodim.

Description

A clethodim amine salt, its preparation method and its application Technical Field

[0001] This application relates to the field of agricultural herbicides, and in particular to a clethodim-amine salt, its preparation method, and its application. Background Technology

[0002] Clethodim, chemically known as 2-{1-[(3-chloro-2-allyl)oxy]iminopropyl}-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one, is a cyclohexanedione herbicide with excellent herbicidal activity. Currently, commercially available industrial clethodim products are liquids with a content of 86-93%. The presence of multiple non-adjacent carbon-carbon double bonds and oxime functional groups in the clethodim structure determines its poor stability, susceptibility to configurational inversion under external conditions, and sensitivity to ultraviolet light, heat, strong acids, and strong alkalis. Therefore, it is prone to decomposition during long-term transportation and storage, leading to a decrease in clethodim content and reduced herbicidal efficacy. Once clethodim decomposes, the reduced content of the active ingredient severely impacts subsequent formulation processing and efficacy. Therefore, reducing the decomposition rate of clethodim technical and formulations during storage, improving stability, and increasing the content of the active ingredient are crucial. Meanwhile, currently available clethodim formulations are all emulsifiable concentrates (EC), such as 240EC and 360EC formulations, and there are no solid formulations, such as water-dispersible granules (WG) or wettable powders (WP), which limits the application scenarios and commercial use of clethodim.

[0003] Different clethodim salts have different levels of stability, physicochemical properties, herbicidal activity, and efficacy. Different clethodim salts will bring different efficacy and effects, and the formulations and properties of economically important preparations may be different.

[0004] Therefore, there is a need to develop new clethodim derivatives that exhibit one or more improved properties, such as improved storage stability, improved herbicidal activity, and efficacy.

[0005] Summary of the Invention

[0006] To address the issues of poor stability and rapid decline in herbicidal efficacy of clethodim, this application provides a clethodim amine salt, its preparation method, and its application.

[0007] The first inventive objective of this application is achieved through the following technical solution:

[0008] A clethodim amine salt, specifically clethodim tert-butylamine salt, has the following chemical structural formula:

[0009] Optional: Clethodim salt can be characterized by one or more of the following methods, including but not limited to high performance liquid chromatography (HPLC), nuclear magnetic resonance (HNMR), and differential scanning calorimetry (DSC) curves showing an endothermic melting peak at 104 °C and a melting range of 93-107 °C.

[0010] By adopting the above technical solutions, the structure of clethodim tert-butylamine salt has been confirmed in this application, including but not limited to nuclear magnetic resonance (HNMR), differential scanning calorimetry (DSC), etc. As shown in Figure 1, the clethodim tert-butylamine salt of this application is characterized by a hydrogen nuclear magnetic resonance (HNMR) spectrum, and as shown in Figure 2, the clethodim tert-butylamine salt of this application is characterized by a differential scanning calorimetry (DSC) spectrum.

[0011] The clethodim tert-butylamine salt prepared in this application has good stability, which is superior to that of clethodim and other clethodim amine salts, while maintaining herbicidal activity no weaker than that of clethodim. The degradation rate of this clethodim tert-butylamine salt during high-temperature thermal storage is lower than that of clethodim and other clethodim amine salts reported in the literature, and it is easier to store for a long time than clethodim.

[0012] The second inventive objective of this application is achieved through the following technical solution:

[0013] A method for preparing the above-mentioned clethodim salt, the method comprising the following steps:

[0014] S1: Dissolve clethodim in a solvent to obtain mixture A;

[0015] S2: Add tert-butylamine to mixture A to carry out the reaction. After the reaction is completed, clethodim amine salt is precipitated out of the reaction system.

[0016] S3: Separate the precipitate to obtain clethodim salt.

[0017] By adopting the above technical solution, the method for preparing clethodim salt is simple, the process is mature and stable, and the yield is high and the production cost is low. Compared with the currently commercialized clethodim technical, the content of clethodim salt product can be significantly improved.

[0018] Optional: The reaction temperature in S2 is -5℃ to 45℃.

[0019] By adopting the above technical solution, the reaction conditions of the preparation method in this application are mild, and the process is mature and safe.

[0020] Optional: The molar ratio of clethodim to tert-butylamine in S2 is (1:1.2) to (1:1).

[0021] By adopting the above technical solution, the yield and content of clethodim tert-butylamine salt product are high.

[0022] Optional: The clethodim salt obtained in S3 is further purified by washing.

[0023] By adopting the above technical solution, the content of clethodim tert-butylamine salt product is high.

[0024] The third inventive objective of this application is achieved through the following technical solution:

[0025] The application of the above-mentioned clethodim salt in herbicides.

[0026] By adopting the above technical solution, clethodim tert-butylamine salt has good stability and herbicidal efficacy, and is expected to be prepared into a commercially viable formulation with economic value, and has excellent storage stability and good efficacy.

[0027] In summary, this application has at least the following beneficial effects:

[0028] 1. This application discloses clethodim tert-butylamine salt and characterizes it by various means; the long-term storage stability of the clethodim tert-butylamine salt of this application is improved, which is not only superior to clethodim, but also superior to other clethodim amine salts. While improving stability, it still has excellent herbicidal activity; and the stability and herbicidal activity of the clethodim tert-butylamine salt prepared in this application are superior to other clethodim amine salts reported in the literature.

[0029] 2. The preparation method of this application has mild reaction conditions, mature process, good stability, high yield and low production cost. Compared with the currently commercialized clethodim technical, the content of clethodim amine salt product can be significantly increased.

[0030] 3. The clethodim tert-butylamine salt of this application is beneficial for the preparation of commercially viable formulations with economic value, and has superior storage stability and good efficacy. The clethodim tert-butylamine salt of this application has a lower degradation rate during high-temperature thermal storage than clethodim and other clethodim amine salts reported in the literature, and is easier to store for a long time than clethodim, which is beneficial for the shelf-life stability of commercial products. At the same time, it is beneficial to change the current single formulation of commercial clethodim and expand to clethodim solid formulations, such as water-dispersible granules (WG) or wettable powders (WP), etc., with good commercial prospects. Attached Figure Description

[0031] The various features and aspects of the embodiments of this application disclosed herein can be more clearly understood by referring to the accompanying drawings, which are intended to illustrate and explain rather than limit the scope of this application, and wherein:

[0032] Figure 1 shows the 1H NMR spectrum of clethodim tert-butylamine salt.

[0033] Figure 2 shows the differential scanning calorimetry (DSC) curve of clethodim tert-butylamine salt. DETAILED DESCRIPTION

[0034] Example 1

[0035] A kind of clethodim amine salt, which is clethodim tert-butylamine salt, and its chemical structure is as follows:

[0036] The preparation method of the clethodim tert-butylamine salt is as follows:

[0037] S1: 40.2g clethodim technical material (89.5wt%, 0.10mol) and 25g solvent A were stirred and mixed uniformly at a temperature of 16℃, the mixing temperature was increased to 18℃, and 7.39g of tert-butylamine liquid (99wt%, 0.1mol) was added at a constant speed for 5min, and then stirred at 18℃ for 1.0h after the addition was completed, and 120.0g of solvent B was added to obtain mixture A;

[0038] S2: continue to stir the reaction at 15℃ for 5.0h to obtain the reaction material;

[0039] S3: the reaction material was filtered to obtain a solid;

[0040] S4: the solid was washed with 5 times the mass of solvent B, and then vacuum dried at 20℃ to obtain the product clethodim tert-butylamine salt.

[0041] Solvent A is toluene, and solvent B is cyclohexane.

[0042] Examples 2-7

[0043] A kind of clethodim tert-butylamine salt, which is different from example 1 in that the process parameters of the preparation method are different, and the specific differences are shown in table 1.

[0044] Table 1. Preparation method parameter table of examples 1-7

[0045] The products obtained in examples 1-7 were detected by high performance liquid chromatography (HPLC) and the yield was calculated, and the results are shown in table 2.

[0046] Table 2. Purity and yield of products of examples 1-7

[0047] As can be seen from table 1 and table 2, when clethodim reacts with tert-butylamine to obtain the target product of the present application, in order to ensure the effective use of clethodim, the yield is improved by appropriately increasing the amount of tert-butylamine. As can be seen from comparative examples 1-2 and examples 5-6, too much excess tert-butylamine has a negative impact on the yield and product content, and considering the product production cost and the final product amount index, therefore, the molar ratio of clethodim to tert-butylamine in the present application is controlled to be (1:1)-(1:1.2).

[0048] As can be seen from Examples 1 to 4, when the preparation method of the present application is used to obtain the alkylammonium salt of alkeneone, the reaction temperature is appropriately adjusted to be within the range of -5 to 45°C, and the reaction time is appropriately adjusted, and the target product with high purity can be obtained in high yield. The reaction time is longer at lower temperature. The preparation method has low production cost, is mature and simple, has good stability, and has high yield.

[0049] As can be seen from Example 2 and Example 7, the liquid phase environment used in the reaction of the alkylammonium salt of alkeneone can be one of chloroalkanes and benzene solvents.

[0050] The sample of Example 2 with the highest product purity was selected as the test sample for testing, and the melting point was 92 to 94°C. Stability test was performed.

[0051] Comparative Example 1

[0052] An alkylammonium salt of alkeneone, which is different from Example 2 in that the amine used in S2 is sec-butylamine, and the molar ratio of alkeneone to sec-butylamine is 1:1.1. The obtained alkylammonium salt of alkeneone is specifically shown in Table 3.

[0053] Comparative Example 2

[0054] An alkylammonium salt of alkeneone, which is different from Example 2 in that the amine used in S2 is sec-butylamine, and the molar ratio of alkeneone to sec-butylamine is 1:1.1. The obtained alkylammonium salt of alkeneone is specifically shown in Table 3.

[0055] Comparative Examples 3 to 7

[0056] An alkylammonium salt of alkeneone, which is different from Example 2 in that the amine used in S2 is different, and the molar ratio of alkeneone to amine is 1:1.1. The obtained alkylammonium salt of alkeneone is specifically shown in Table 3.

[0057] The content and melting point of the alkylammonium salt of alkeneone obtained in Comparative Examples 1 to 7 were detected, and the yield was calculated. The results are recorded in Table 3.

[0058] The melting point of the product was detected by extracting 12 samples of the same test object. The maximum deviation of the detection results was within 5°C. The melting point result distribution range was recorded. If the maximum deviation was greater than 5°C, the test object was prepared again and the sample was extracted for detection.

[0059] Table 3. Information table of amine used in Comparative Examples 1 to 7, product content, and yield table

[0060] *The melting point of the clethodim salt obtained in Comparative Example 7 fluctuated by more than 10°C during the melting point test, and multiple resampling measurements failed to obtain test results within the fluctuation range of 5°C. Analysis showed that this was because the clethodim salt content was too low, and the decomposition of clethodim or other byproducts during heating triggered the decomposition of the clethodim salt.

[0061] The stability of the samples obtained in Example 2 and Comparative Examples 1-7 was tested by accelerated storage test.

[0062] According to the international method for the physicochemical determination of pesticide technicals and formulations—CIPAC method—CIPAC MT 46.4 Accelerated Storage procedure stipulates that pesticide technicals and formulations have a shelf life of at least 2 years under standard operating conditions. The shelf life of pesticide technicals and formulations under standard operating conditions can be determined through accelerated storage testing. Accelerated storage testing is conducted according to the following six combinations of storage temperature and storage period specified in CIPAC MT 46.4 Accelerated Storage procedure. The test results for residual active ingredients in the samples can be considered as predictive values ​​for 2-year storage:

[0063] (1) 54±2℃, for 14 consecutive days;

[0064] (2) 50±2℃, for 4 weeks;

[0065] (3) 45±2℃, for 6 weeks;

[0066] (4) 40±2℃, for 8 weeks;

[0067] (5) 35±2℃, for 12 weeks;

[0068] (6) 30±2℃, for 18 weeks;

[0069] That is, storing at 54±2℃ for 14 days is equivalent to storing at 50±2℃ for 4 weeks, and so on.

[0070] In the combination of storage temperature and storage period, storage temperature has a significant impact on the accelerated storage testing of pesticide technicals and formulations, determining the accelerated storage testing cycle and reflecting the upper limit of extreme conditions that pesticide technicals and formulations can tolerate during storage.

[0071] This application selects "54±2℃ for 14 days" as the test parameter. The CIPAC method, the international standard for the physicochemical determination of pesticide technicals and formulations, is cited here. The rate of change curves of samples differ under different parameters, making conversion impractical. For example, the results of a sample at 54±2℃ for 7 days are not the same as those of a sample at 35℃±2℃ for 6 weeks.

[0072] The specific testing method is as follows: the sample is sealed in an ampoule and stored in a constant temperature chamber at 54±2℃ for 14 days. Then, high performance liquid chromatography is used to analyze the change in purity of the active ingredient before and after heat storage. A commercially available clethodim sample (mass content of 89.50%) is used as a control example.

[0073] The test results are shown in Table 4.

[0074] Table 4. Stability test results of Example 2 and Comparative Examples 1-7

[0075] The sample content refers to the content of the corresponding active ingredient (clethodim or clethodim) in the sample after heat storage; the decomposition rate is calculated as follows: decomposition rate (%) = (initial content - heat storage sample content) / initial content × 100%.

[0076] During the research process of this application, it was found that some of the samples in Comparative Examples 1 to 7 decomposed relatively quickly when stored at 54±2℃. In order to better and more comprehensively compare Example 2 and Comparative Examples 1 to 7, in addition to the 14 days at 54±2℃ required by the CIPAC MT 46.4 Accelerated Storage procedure, this application also independently conducted tests on the same samples at 54±2℃ for 3 days and 7 days to better indicate the decomposition during storage and reflect the stability performance of each sample.

[0077] As shown in Table 4, after 14 days of accelerated storage at 54±1℃, the samples of Comparative Examples 1-7 and the Control Example all showed significant decomposition, while the decomposition in Example 2 was gradual and the final decomposition rate after 14 days was much lower than that in Examples 1-7. Therefore, the stability of clethodim in this application is superior to that of clethodim and other clethodim salts, and it is reasonable to infer that the prepared technical grade or formulation is not easily decomposed during long-term storage.

[0078] In addition, samples were obtained from Example 2 (clethodim tert-butylamine salt), Comparative Example 1 (clethodim tert-secondary amine salt), and Comparative Example 2 (clethodim tert-isoamine salt) for herbicidal testing.

[0079] Herbicidal efficacy test: The test was conducted according to the herbicide test method in Part 4 of the Guidelines for Indoor Bioassay of Pesticides: Foliar Spray Test (NY / T 1155.4-2006). The test targets were barnyard grass, sedge, and goosegrass. A commercially available clethodim sample (content 89.50%) was used as a control. The test results were the fresh weight control efficacy against weeds at different application rates over 21 days.

[0080] The results of the weed control test are shown in Table 5.

[0081] Table 5. Results of herbicide test in Example 2 and Comparative Examples 1-2*

[0082] *Note: The table shows the 21-day fresh weight control efficacy of the drug against different weeds at two different dosages.

[0083] Analysis of experimental results: When the dosage is 6.25g ai / hm 2 At 21 days post-application, the herbicidal activity of different herbicides against barnyard grass, from lowest to highest, was: Comparative Example 2 < Comparative Example 1 < Example 2 < Control Example; the herbicidal activity against *Clerodendrum trichotomum*, from lowest to highest, was: Comparative Example 2 < Comparative Example 1 < Example 2 < Control Example; the herbicidal activity against *Eleusine indica*, from lowest to highest, was: Comparative Example 2 < Comparative Example 1 < Example 2 < Control Example; when the dosage was 12.5 g ai / hm 2 At 21 days post-application, the herbicidal activity of different agents against barnyardgrass, from lowest to highest, was: Comparative Example 2 < Comparative Example 1 < Control Example < Example 2; the herbicidal activity against barnyardgrass, from lowest to highest, was: Comparative Example 1 < Comparative Example 2 < Example 2 < Control Example; and the herbicidal activity against goosegrass, from lowest to highest, was: Comparative Example 2 < Comparative Example 1 < Control Example < Example 2.

[0084] The results in Table 5 show that the fresh weight efficacy of Example 2 is similar to that of the control example, with good herbicidal activity and no significant attenuation, even at a dosage of 12.5 g ai / hm. 2 At that time, the herbicidal activity against barnyard grass and goosegrass was slightly better than that against the control.

[0085] Compared to the control, Comparative Examples 1 and 2 showed a significant decrease in herbicidal activity at different dosages.

[0086] The data above shows that different clethodim-amine salts exhibit varying physicochemical properties, leading to significant differences in their stability and herbicidal activity. Even isomers of amines (tert-butylamine, sec-butylamine, isobutylamine) and clethodim-formed clethodim-amine salts (clethodim tert-butylamine salt, clethodim sec-butylamine salt, clethodim isobutylamine salt) show significant differences in storage stability and herbicidal activity. Furthermore, the processing difficulty, product performance, and economic costs of different clethodim-amine salts in various formulations may differ. The clethodim tert-butylamine salt disclosed in this application is a compound with excellent overall performance and broad commercial prospects.

[0087] In addition, the sample of Example 2 was subjected to 1H NMR spectroscopy and differential scanning calorimetry to further determine the structure of the sample of Example 2. The detection diagrams are shown in Figure 1 and Figure 2.

[0088] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of protection claimed in this application.

Claims

1. A clethodim-amine salt, characterized in that, The clethodim amine salt is clethodim tert-butylamine salt, and its chemical structural formula is as follows:

2. The clethodim amine salt according to claim 1, characterized in that: The clethodim amine salt was characterized by one or more of the following methods: high performance liquid chromatography, nuclear magnetic resonance, and differential scanning calorimetry curves showing an endothermic melting peak at 104 °C and a melting range of 93-107 °C.

3. A method for preparing a clethodim-amine salt as described in claim 1, characterized in that: The method includes the following steps: S1: Dissolve clethodim in a solvent to obtain mixture A; S2: Add tert-butylamine to mixture A to carry out the reaction. After the reaction is completed, clethodim amine salt is precipitated out of the reaction system. S3: Separate the precipitate to obtain clethodim salt.

4. The method for preparing clethodim-amine salt according to claim 3, characterized in that: The reaction temperature in S2 ranges from -5℃ to 45℃.

5. The method for preparing clethodim-amine salt according to claim 3, characterized in that: The molar ratio of clethodim to tert-butylamine in S2 is (1:1) to (1:1.2).

6. The method for preparing clethodim amine salt according to claim 3, characterized in that: The clethodim salt obtained in S3 was further purified by washing.

7. The application of the clethodim salt as described in claim 1 in a herbicide.

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