2m sodium chlorthal-dimethylate complex, microspheres containing the complex, and methods of making and using the same

Abstract

The application belongs to the technical field of pesticide active components, and relates to a 2-methyl-4-chloro sodium complex, microspheres containing the complex, a preparation method and application. A 2-methyl-4-chloro sodium solution is uniformly mixed with a metal ion compound solution, centrifuged, washed and dried to obtain a crude complex. The crude complex is mixed with a surfactant and then ground in water to obtain a 2-methyl-4-chloro sodium complex suspension agent. The 2-methyl-4-chloro sodium complex is mixed with a tannic acid solution to obtain 2-methyl-4-chloro sodium complex microspheres. The complex and the microspheres have the technical advantages of rainwater erosion resistance and easy photolysis on the basis of obvious activity improvement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pesticide active ingredients, and relates to a 2-methyl-4-chlorophenoxyacetic acid sodium complex, microspheres containing the complex, and a preparation method and application thereof. BACKGROUND

[0002] 2-methyl-4-chlorophenoxyacetic acid sodium (MCPA-Na, molecular formula: C9H8ClO3Na, molecular weight: 222.44) is a new type of herbicide, which is widely used in crop fields such as rice, wheat, corn, sorghum, sugarcane, flax, etc. to control broadleaf weeds such as spiderwort, pig grass, motherwort, shepherd's purse, bottle grass, three-edged grass, and hornwort. 2-methyl-4-chlorophenoxyacetic acid sodium is a selective systemic herbicide, which can penetrate the cuticle and cell membrane to enter various parts of the plant after being sprayed on the surface of the weed stems and leaves, affect the synthesis of plant nucleic acid and protein, and eventually cause the death of the weeds. 2-methyl-4-chlorophenoxyacetic acid sodium has very high water solubility, and in the rainy season in summer, especially in the south where the rainfall is frequent and the rainfall is large, 2-methyl-4-chlorophenoxyacetic acid sodium is very easy to be washed away, resulting in poor weed control effect. At the same time, the washed pesticide can cause problems such as exceeding the standard of 2-methyl-4-chlorophenoxyacetic acid sodium in farmland groundwater and rivers and lakes. Therefore, it is urgent to solve the problem of improving the wash-off resistance of 2-methyl-4-chlorophenoxyacetic acid sodium and improving its environmental friendliness. SUMMARY

[0003] The application provides a novel 2-methyl-4-chlorophenoxyacetic acid sodium complex and a preparation method and application of microspheres containing the complex to solve the problems of high water solubility, easy washing, and low control effect of traditional 2-methyl-4-chlorophenoxyacetic acid sodium in use.

[0004] In order to achieve the above-mentioned purpose, the application is realized by the following technical scheme:

[0005] The application provides a 2-methyl-4-chlorophenoxyacetic acid sodium complex suspension agent and microspheres containing the complex, wherein the preparation steps of the 2-methyl-4-chlorophenoxyacetic acid sodium complex suspension agent are as follows:

[0006] (1) uniformly mix a 2-methyl-4-chlorophenoxyacetic acid sodium solution and a metal ion compound solution to obtain a crude complex A suspension.

[0007] (2) centrifuge the crude complex A suspension, wash and dry the obtained solid after centrifugation to obtain a crude complex A powder.

[0008] (3) grind the crude complex A powder in water after mixing with a surfactant to obtain a 2-methyl-4-chlorophenoxyacetic acid sodium complex suspension agent.

[0009] Mix the 2-methyl-4-chlorophenoxyacetic acid sodium complex suspension agent prepared by the above steps with a tannic acid solution to obtain a 2-methyl-4-chlorophenoxyacetic acid sodium complex microsphere suspension agent.

[0010] Preferably, the metal ions include any one or several of iron ions, zinc ions, copper ions, manganese ions, calcium ions, and aluminum ions.

[0011] Preferably, the mass fraction of the 2-methyl-4-chloropropane sodium solution and the metal ion compound solution in step (1) is 0.5-20%, and the molar ratio of 2-methyl-4-chloropropane sodium and the metal ion compound is 1:(0.2-6).

[0012] Preferably, the surfactant in step (3) is a Tween series surfactant and / or a block polyether surfactant, and the mass ratio of the surfactant and the crude complex A powder is 1:(0.5-10).

[0013] The present application provides the 2-methyl-4-chloropropane sodium complex suspension prepared by the above method and the application of the 2-methyl-4-chloropropane sodium complex microsphere suspension in herbicides.

[0014] Preferably, the mass fraction of the 2-methyl-4-chloropropane sodium complex or microsphere in the herbicide is 0.01-60%.

[0015] Compared with the prior art, the present application has the following advantages and positive effects:

[0016] The present application successfully prepares the 2-methyl-4-chloropropane sodium complex with good washing resistance and improved activity by complexing 2-methyl-4-chloropropane sodium with metal ions and modifying by a surfactant, and further prepares the complex microspheres by wrapping with tannic acid, which has the technical advantages of rain washing resistance and easy photolysis on the basis of obviously improved activity. The present application solves the problems of rain washing invalidation and low herbicidal activity of the current 2-methyl-4-chloropropane herbicide, conforms to the current green and environmentally-friendly production concept, has a simple preparation process, stable product quality, and is suitable for large-scale popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 a is a microscope photograph of the 2-methyl-4-chloropropane sodium complex suspension prepared in Example 1, Figure 1 b is a microscope photograph of the 2-methyl-4-chloropropane sodium / iron / tannic acid microsphere suspension prepared in Example 1.

[0018] Figure 2 a is a SEM photograph of the 2-methyl-4-chloropropane sodium complex suspension prepared in Example 1, Figure 2 b is a SEM photograph of the 2-methyl-4-chloropropane sodium / iron / tannic acid microsphere suspension prepared in Example 1.

[0019] Figure 3 a is a TEM photograph of the 2-methyl-4-chloropropane sodium complex suspension prepared in Example 1, Figure 3 b is a TEM photograph of the 2-methyl-4-chloropropane sodium / iron / tannic acid microsphere suspension prepared in Example 1.

[0020] Figure 4 XRD patterns of the 2M4P sodium complex suspension and the 2M4P sodium / iron / tannic acid microsphere suspension prepared in Example 1.

[0021] Figure 5 The leaf pesticide ingredient retention curve.

[0022] Figure 6 The leaf pesticide ingredient photolysis curve. DETAILED DESCRIPTION

[0023] In order to enable a more complete understanding of the above-mentioned objects, features and advantages of the present application, the present application will be described in further detail below with reference to specific examples. It should be noted that the examples of the present application and the features in the examples can be combined with each other without conflict, if necessary.

[0024] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in different manners than those described herein, and therefore the present application is not limited to the specific embodiments disclosed in the following description.

[0025] Example 1

[0026] 0.3 mol of 2M4P sodium was added to deionized water to prepare a 2M4P sodium solution with a mass fraction of 20%, and 0.1 mol of ferric chloride hexahydrate was added to deionized water to prepare a ferric chloride hexahydrate solution with a mass fraction of 5%. The 2M4P sodium solution and the ferric chloride hexahydrate solution were mixed, and stirred at a speed of 500 rpm for 2 hours. The mixture was centrifuged at a speed of 8000 rpm for 5 min, and the supernatant was discarded. Deionized water was added to the centrifuge tube, and the tube was shaken and washed 3 times. Then, the solid was scraped and dried in an oven at 60°C for 6 hours to obtain a 2M4P sodium / iron complex crude powder. 1 g of the complex crude powder was added to 98 g of deionized water, and 1 g of Tween 80 was added. After stirring and mixing, the mixture was poured into a vertical sand mill, and ground at a speed of 1800 rpm for 2 hours. During the grinding process, the mill was cooled by condensed water. After the grinding process, a 2M4P sodium complex suspension with a mass fraction of 1% was obtained.

[0027] The 2M4P sodium complex suspension with a mass fraction of 1% and a tannic acid aqueous solution with a mass fraction of 1% were mixed in equal volumes to obtain a 2M4P sodium / iron / tannic acid microsphere suspension with a mass fraction of 1%.

[0028] 2MCP-Na complex suspension and 2MCP-Na / Fe / tannic acid microspheres suspension can be directly used as active ingredients of pesticides. If not used for a long time, they need to be sealed and stored. Before use, they are manually shaken and then diluted with deionized water or tap water to the corresponding concentration. It is detected that the morphology and efficacy of 2MCP-Na complex suspension and 2MCP-Na / Fe / tannic acid microspheres suspension prepared in this embodiment do not change significantly after being sealed and stored for 6 months.

[0029] Example 2

[0030] The unexplained part of this embodiment is consistent with the preparation process in Example 1.

[0031] 0.5 mol of 2MCP-Na is added to deionized water to prepare a 5% 2MCP-Na solution, and 0.1 mol of zinc chloride is added to deionized water to prepare a 0.8% zinc chloride solution. The above 2MCP-Na solution and zinc chloride solution are mixed, continuously stirred at a speed of 500 rpm for 2 hours, centrifuged at 8000 rpm for 5 min, the supernatant is discarded, deionized water is added to the centrifuge tube and shaken for 3 times, then the solid is scraped and placed in a 60°C oven for drying for 6 hours to obtain a 2MCP-Na / zinc complex crude powder. 1 g of the complex crude powder is added to 98 g of deionized water, 1 g of a block polyether surfactant (Beijing Guangyineng Chemical Co., Ltd., dispersant 1700) is added, stirred and mixed, then poured into a vertical sand mill, and ground at 1800 rpm for 2 hours to obtain a 1% 2MCP-Na complex suspension.

[0032] The 1% 2MCP-Na complex suspension and the 1% tannic acid aqueous solution are mixed in equal volume to obtain a 1% 2MCP-Na / zinc / tannic acid microspheres suspension.

[0033] Example 3

[0034] The unexplained part of this embodiment is consistent with the preparation process in Example 1.

[0035] A 0.1 mol solution of 2MCP-Na was prepared by adding 2MCP-Na to deionized water to a concentration of 20% by mass. A 0.6 mol solution of CaCl2 was prepared by adding CaCl2 to deionized water to a concentration of 5% by mass. The 2MCP-Na solution and the CaCl2 solution were mixed and stirred at 500 rpm for 2 hours. The mixture was centrifuged at 8000 rpm for 5 minutes, and the supernatant was discarded. The centrifuge tube was washed with deionized water three times by adding deionized water, shaking, and then scraping the solid and drying in an oven at 60°C for 6 hours to obtain a 2MCP-Na / Ca complex powder. A 1% by mass 2MCP-Na complex suspension was prepared by adding 1 g of the complex powder to 98 g of deionized water and adding 1 g of Tween 80. The mixture was stirred and then poured into a vertical sand mill and ground at 1800 rpm for 2 hours.

[0036] A 1% by mass 2MCP-Na / Ca / tannic acid microsphere suspension was prepared by mixing equal volumes of the 1% by mass 2MCP-Na complex suspension and a 1% by mass tannic acid solution.

[0037] I. Characterization of the 2MCP-Na complex suspension and the 2MCP-Na / Ca / tannic acid microsphere suspension prepared in Example 1.

[0038] 1. Microscope photography

[0039] The 2MCP-Na complex suspension and the 2MCP-Na / Fe / tannic acid microsphere suspension were diluted with deionized water to 20 times the volume, applied to a glass slide, and photographed under a microscope. The results are shown in Figure 1 a. As can be seen in Figure 1 a, the 2MCP-Na complex is transparent, with a fuzzy boundary, is flexible, and has a persimmon-like shape with a concave center and a convex periphery. Figure 1 b clearly shows that the 2MCP-Na / Fe / tannic acid microspheres have a clear boundary, are weakly transparent, and are smaller and more compact than the complex.

[0040] 2. SEM characterization

[0041] The 2MCP-Na complex suspension and the 2MCP-Na / Fe / tannic acid microsphere suspension were diluted with deionized water to 20 times the volume, applied to a silicon wafer, and photographed under a scanning electron microscope. The results are shown in Figure 2 Figure 2 a. As can be seen in Figure 2 a, the 2MCP-Na complex has an irregular shape and a soft boundary, while b clearly shows that the 2MCP-Na / Fe / tannic acid microspheres have a clear boundary, a regular shape, and a smaller particle size.

[0042] 3. TEM characterization

[0043] The 2-methyl-4-chloro sodium complex suspension agent and the 2-methyl-4-chloro sodium / iron / tannic acid microsphere suspension agent were diluted with 20 times volume of deionized water, then coated on a copper mesh for transmission electron microscope photographing, and the results are shown in Figure 3 a、b. Figure 3 As can be seen from the comparison between a and b, the 2-methyl-4-chloro sodium complex has a uniform texture, while the 2-methyl-4-chloro sodium / iron / tannic acid microsphere has a thick middle and thin edge, and it is speculated that the thin edge is the tannic acid shell.

[0044] 4. XRD characterization

[0045] The 2-methyl-4-chloro sodium complex suspension agent and the 2-methyl-4-chloro sodium / iron / tannic acid microsphere suspension agent were placed in an oven and dried at 60°C for more than 6h, then the dried 2-methyl-4-chloro sodium complex and 2-methyl-4-chloro sodium / iron / tannic acid microsphere were subjected to phase analysis by X-ray diffractometer, with 2θ, angle range and scanning rate being 0.02°, 10°-60° and 2° / min respectively, and the X-ray electron diffraction (XRD) patterns of 2-methyl-4-chloro sodium, 2-methyl-4-chloro sodium complex and 2-methyl-4-chloro sodium / iron / tannic acid microsphere are shown in Figure 4 . Figure 4 a is the XRD pattern of unmodified 2-methyl-4-chloro sodium, and from Figure 4 a, it can be seen that the XRD pattern of unmodified 2-methyl-4-chloro sodium has sharp diffraction peaks, and the phase is crystalline; while the XRD patterns of the 2-methyl-4-chloro sodium complex (b) and the 2-methyl-4-chloro sodium / iron / tannic acid microsphere (c) show a large envelope peak, and no obvious sharp crystal diffraction peak is observed, indicating that the 2-methyl-4-chloro sodium complex and the 2-methyl-4-chloro sodium / iron / tannic acid microsphere are amorphous phases, and thus they are different from the 2-methyl-4-chloro sodium complex and the microsphere. Figure 4 . Figure 4

[0046] II. Effect verification

[0047] The 2-methyl-4-chloro sodium complex suspension agent and the 2-methyl-4-chloro sodium / iron / tannic acid microsphere suspension agent prepared in Example 1 were subjected to effect verification as follows.

[0048] 1. Herbicidal activity verification

[0049] ​The broadleaf weed Amaranthus retroflexus L. in corn field was selected, and the seeds were collected in September 2023 in Lican Town, Mengcheng County, Bozhou City, Anhui Province (116.695503 °E / 33.060676 °N). The flower pot was a square flower pot with an upper diameter of about 10 cm, a bottom diameter of about 7 cm, and a height of about 8 cm; the soil was mixed evenly in a volume ratio of 1:1 of substrate soil and nutrient soil; when planting, the mixed soil was added to the pot, compacted and leveled, filled to 4 / 5 of the plastic pot, and watered from the bottom of the pot using seepage irrigation, so that the soil was fully saturated with water, 6 uniform seeds were scattered into each pot, and the pot was placed in a greenhouse for cultivation, the temperature in the greenhouse was about 25-30 °C, and sufficient water was supplemented every other day to keep the soil moist. After natural growth to 4-6 leaf stage, it was used.

[0050] Pesticide treatment: the test pesticides were 2 methyl 4 sodium chloride complex suspension and 2 methyl 4 sodium chloride / iron / tannic acid microspheres suspension obtained in Example 1, and the commercially available 2 methyl 4 sodium chloride wettable powder (Anhui Yinnong Chemical Co., Ltd.) with a mass fraction of 56% was used as a control; the dosage of the pesticide was 125 g / ha, calculated based on 30 kg water per mu, according to the recommended dosage of 56% wettable powder in the field (100-150 kg / ha), and the effective concentration of 1 times the recommended dosage in the field was about 0.2333%; the effective mass concentration of 2 methyl 4 sodium chloride complex suspension (labeled as group a) and 2 methyl 4 sodium chloride / iron / tannic acid microspheres suspension (labeled as group b) prepared in Example 1 was diluted to 0.2333% with tap water.

[0051] Spraying method: when the Amaranthus retroflexus L. grew to 4-6 leaf stage, the above 1 times the recommended dosage in the field was used for stem and leaf spraying, a 3WP-2000 walking type spraying tower was used, the spraying pressure was 275 kPa, the spraying amount of a group, b group and control group was 450 L / hm 2 , the distance between the nozzle and the soil surface in the flower pot was about 30 cm. Three pots were set for each pesticide treatment, and each pot contained 6 Amaranthus retroflexus L. plants. The same quality of water was used as a blank control, and the treated weeds were placed back in the greenhouse for further cultivation.

[0052] Data processing: 14 days after pesticide treatment, the aboveground stems and leaves of the weeds were cut and weighed to calculate the fresh weight inhibition rate. The fresh weight inhibition rate 14 days after spraying was calculated according to the following formula:

[0053] .

[0054] The experimental results are shown in Table 1 below:

[0055] Table 1 Activity determination results of 2 methyl 4 sodium chloride complex and microspheres suspension on Amaranthus retroflexus L.

[0056]

[0057] From Table 1, it can be seen that the 2M4P sodium complex suspension prepared in Example 1 and the 2M4P sodium / iron / tannic acid microsphere suspension both exhibit higher fresh weight inhibition activity than the commercially available 2M4P sodium wettable powder (control), and the standard deviation is smaller than that of the control, meaning that they can more stably and reliably exert herbicidal activity in the field under multi-factor scenarios. At the same time, the 2M4P sodium / iron / tannic acid microsphere suspension has better inhibition effect at a lower effective concentration of 2M4P sodium than the 2M4P sodium complex suspension, proving that the 2M4P sodium / iron / tannic acid microsphere suspension has better activity enhancement. The 2M4P sodium complex suspension and the 2M4P sodium / iron / tannic acid microsphere suspension prepared in Example 1 both have obvious synergistic activity, and the synergistic effect is particularly significant at low concentrations, which has great potential in pesticide reduction and synergism, and is consistent with the policy requirements of national fertilizer and pesticide reduction.

[0058] 2. Erosion resistance verification

[0059] The 2M4P sodium complex suspension prepared in Example 1 was diluted with deionized water to a concentration of 20 mg / L, 100 μL was uniformly applied to the surface of the slide using a pipette, and 3 slides were treated for each sample. In order to improve the wetting efficiency of the liquid on the slide, 0.01% organic silicon was added as a wetting agent in the diluent. Then, the slide with the liquid was placed in a room temperature and light-avoiding condition and naturally dried. The slide had no obvious water stains, and a small spray device was used to uniformly spray deionized water at a flow rate of 15 mL / min at a distance of 20 cm above the slide at an angle of 45° to simulate the behavior of rainwater on the leaf surface. Finally, the slide was taken out after 0 min, 0.5 min, 1 min, 2 min, 4 min, 6 min, and 8 min of erosion and placed in a 50 mL centrifuge tube. 40 mL of ethanol was added to the centrifuge tube, and after ultrasonic treatment for 30 min, the sample was shaken for 5 min. Then, 1 mL of supernatant was taken, filtered through a 0.22 μm organic filter to remove impurities, and the absorbance at 282 nm was measured using a UV spectrophotometer. The standard sample curve was (y = 0.0065x - 0.0012, R² = 0.9994). The 2M4P sodium content remaining on the slide after erosion was determined, and the leaf surface retention rate of 2M4P sodium was calculated. The results are shown in Figure 5 b.

[0060] The commercially available 2M4P sodium wettable powder was used as a control, and the results are shown in Figure 5 a.

[0061] The 2M4P sodium / iron / tannic acid microsphere suspension was treated in the same way as described above, and the results are shown in Figure 5 c.

[0062] From Figure 5 It can be seen from the above table that the control example 2 of mcpa-sodium WP has almost no residue at 2 minutes, which means that it has been almost washed away by rain; while the mcpa-sodium complex SC and the mcpa-sodium / iron / tannic acid microsphere SC both show excellent anti-washing effect, and can still maintain a high residue amount after a longer period of washing, and the mcpa-sodium / iron / tannic acid microsphere SC is better. This shows that the mcpa-sodium complex SC and the mcpa-sodium / iron / tannic acid microsphere SC have good anti-washing performance, can resist the adverse environment of the outside world, reduce the loss of mcpa-sodium, and effectively solve the problem of easy washing of mcpa-sodium itself.

[0063] 3. Photolysis experiment

[0064] The mcpa-sodium complex SC prepared in Example 1 was diluted with deionized water to a concentration of 20 mg / L, 100 μL of which was uniformly applied to the surface of a glass slide using a pipette gun, and 3 glass slides were treated for each sample. In order to improve the wetting efficiency of the liquid on the glass slide, 0.01% of an organic silicon was added as a wetting agent in the diluent. Then, the glass slide with the liquid was placed in a room temperature and light-proof condition and naturally dried, and the glass slide was taken out after 0 h, 1 h, 2 h, 4 h, 6 h, 8 h and 10 h of ultraviolet irradiation, and placed in a 50 mL centrifuge tube. 40 mL of ethanol was added to the centrifuge tube, and after ultrasonic treatment for 30 min, the supernatant was taken out and filtered through a 0.22 μm organic filter membrane to remove impurities. The content of mcpa-sodium on the glass slide after washing was determined by using a UV spectrophotometer to measure the absorbance at 282 nm, and the photolysis rate of mcpa-sodium was calculated. The photolysis curve of the leaf pesticide ingredient was drawn, and the results are shown in 2 Figure 6 b.

[0065] The commercially available mcpa-sodium WP was used as a control, and the results are shown in Figure 6 a.

[0066] The commercially available mcpa-sodium / iron / tannic acid microsphere SC was treated in the same way as described above, and the results are shown in Figure 6 c.

[0067] From Figure 6 ​It can be seen from the above that the photolysis rate of 2MCP-Na WP is the slowest, which means that its impact on the environment is also the most persistent, while the degradation rate of 2MCP-Na complex SC and 2MCP-Na / Fe / tannic acid microsphere SC is far superior to that of 2MCP-Na, and under the premise of ensuring the herbicidal effect, the degradation rate of the pesticide is faster, which means that the pressure on the environment is smaller, the environmental friendliness is higher, and it is more in line with the concept of green and sustainable development.

[0068] Comparative Example 1

[0069] The difference between the present comparative example and Example 1 is that the amount of Tween 80 is 0.1 g, and the rest of the preparation process is consistent with Example 1. The results show that the shape of the obtained 2MCP-Na complex is irregular under a microscope, and the boundary is clear, and the resistance to flushing is poor.

[0070] The above is only a preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any skilled person in the art can modify or change the above disclosed technical content to equivalent embodiments applied to other fields, but any simple modification, equivalent change and modification of the above embodiments made in accordance with the technical essence of the present application without departing from the technical solution content of the present application still belongs to the protection scope of the technical solution of the present application.

Claims

1. A process for the preparation of a suspension concentrate of sodium 2-methyl-4-chloropropionate characterized in that, The steps are as follows: (1) mixing the 2M4P sodium solution and the metal ion compound solution uniformly to obtain a suspension of crude complex A; (2) centrifuging the suspension of crude complex A, washing and drying the obtained solid to obtain crude complex A powder; (3) grinding the crude complex A powder in water after mixing with a surfactant to obtain a 2M4P sodium complex suspension agent; In the step (1), the metal ion is any one or several of iron ion, zinc ion and calcium ion, and the molar ratio of 2M4P sodium to the metal ion compound is 1:(0.2-6); The mass ratio of the surfactant to the crude complex A powder is 1:(0.5-10).

2. A process for the preparation of 2M4C sodium complex suspension concentrate according to claim 1, characterized in that, In the step (1), the mass fraction of the 2M4P sodium solution and the metal ion compound solution is 0.5-20%.

3. The method of preparing 2M4C sodium complex suspension as claimed in claim 1 wherein, In the step (3), the surfactant is a Tween series surfactant and / or a block polyether surfactant.

4. A microsuspension concentrate of sodium 2-methyl-4-chloro-6-(ethylamino)- pyrimidine characterized in that The 2M4P sodium complex suspension agent prepared by any one of claims 1-3 is mixed with a tannic acid solution to obtain.

5. The application of the 2M4P sodium complex suspension agent prepared by the method of any one of claims 1-3 in herbicides.

6. The application of the 2M4P sodium complex microsphere suspension agent of claim 4 in herbicides.

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