Paddy field herbicide Mefenacet
What is Mefenacet (73250-68-7)?
The herbicide Mefenacet is a systemic conduction herbicide. It is mainly absorbed through the shoot sheaths and roots, absorbed through the xylem and roots, and transmitted to the young buds and leaves of the weeds through the xylem and phloem, preventing the cells at the growth point of the weeds from dividing and elongating, eventually causing plant death. It is mainly used to control gramineous weeds in rice fields. It has special effects on barnyardgrass and rice barnyardgrass, and it is also effective on other weeds such as bermudagrass. This product has no hidden phytotoxicity to rice. It is mainly characterized by rapid seedling growth, developed root system and white roots, vigorous growth, and high tillering rate. It is safe for rice seedlings in the 2- to 4-leaf stage.
Physiochemical properties of Mefenacet (73250-68-7)
Cas: 73250-68-7
Molecular formula: C16H14N2O2S
Relative molecular mass: 298.4
Physicochemical properties: This product is solid, mp 134.8℃, vapor pressure 11 MPa (100℃)
Solubility (20℃): water 4 mg/L, hexane 0.1~1.0 g/L, acetone 60~100 g/L, toluene 20~50 g/L, methylene chloride>200 g/L, isopropyl alcohol 5 ~10 g/L, ethyl acetate 20~50g/L, dimethyl vitriol 110~220 g/L, acetonitrile 30~60 g/L.
Stability: stable to acid, alkali, light and heat, 95% unchanged at 30℃ within 0.5 years.
Toxicity: Acute oral LD₅₀＞5000 mg/kg in rats and mice, acute dermal LD₅₀＞5000 mg/kg in rats, acute inhalation LC₅₀ (4 h) 0.02 mg (dusting powder) in rats, no results in the two-year feeding test in rats The effect dose is 100 mg/kg feed, fish toxicity LC₅₀ (96 h): carp 8.0 mg/L, trout 6.8 g/L.
Mefenacet (73250-68-7) Mode of action
It is an anilide herbicide and is a cell growth and division inhibitor. It has a particularly strong inhibitory effect on the division of mother cells. It has been observed that the drug works at the growth point of the plant in the quiescent phase and the metabolic phase of the cell reproduction cycle, and inhibits cell division and enlargement, thereby hindering the growth of barnyardgrass until death. The appearance symptoms of barnyardgrass treated with the drug are: the growth points of the stems, leaves and roots are abnormally hypertrophied, the leaf sheaths turn dark green, the growth of the plants is inhibited, and eventually the stems and leaves turn yellow and die. The withering time of barnyard grass prolongs with the increase of leaf age.
Characteristics of the action of Mefenacet(73250-68-7)
The herbicide mefenacet is a selective systemic conduction type anilide herbicide, an inhibitor of cell growth and division, and has a particularly strong inhibitory effect on the division of mother cells. It is mainly absorbed through the shoots and roots, and is transmitted to the young shoots and young leaves of weeds through xylem and phloem, preventing the cell division and elongation of the growth point of weeds. at the growth point. It inhibits cell division and growth of cells, especially mother cells, thereby hindering the growth of barnyardgrass until it dies.
Symptoms of medicated barnyardgrass include: abnormally enlarged growth points on stems, leaves and roots, leaf sheaths and leaves turning dark green, and plant growth inhibited. Eventually it withers and dies.
Due to its low solubility in water, the herbicidal activity is highest when applied under water-retaining conditions. The soil has a strong adsorption capacity for this product. After application, most of the drug will be adsorbed on the soil surface, and a treatment layer will be formed within 1 cm of the soil surface. It is safe, but it has a strong ability to prevent growth and kill weeds such as barnyardgrass and other weeds whose growth point is on the surface of the soil, and also has an inhibitory effect on perennial weeds that propagate by seeds on the surface, but has a low effect on deep weeds. The fields should be raked flat when used. The effect is poor in dew areas, sandy soil and leaky fields.
Mefenacet (73250-68-7) Product Performance
The herbicide Mefenacet can effectively control grass weeds. It has special effects on barnyard grass from germination to the 2-leaf stage. Sedge, broken rice sedge and perennial aquatic sedge also have certain control effects.
When used, it can be compounded with sulfonylureas such as bensulfuron-methyl and pyrazosulfuron-methyl according to the field grass spectrum.
The herbicide Mefenacet is registered for use in transplanting and transplanting rice fields. It can effectively prevent and control gramineous weeds and has special effects on barnyard grass. It can kill barnyard grass before it occurs to the 3-leaf stage. It has a preventive effect on oxenia, Alisma, duckweed, knotweed, special-shaped sedge, flat spike sedge, awned sedge and perennial water sedge. It has good selectivity for transplanting rice, has quick effect from before emergence to early emergence, and lasts for more than 30 days. It is mainly used to control gramineous weeds. It is a highly active barnyard killer in rice fields and can kill barnyard grass before it occurs to the three-leaf stage. The pesticide application method can be sprinkled with water.
Techniques for using Mefenacet (73250-68-7)
In transplanting and throwing rice fields, 3 to 10 days after transplanting (throwing planting) (barnyardgrass 2 leaf stage), 3 to 14 days (barnyard grass 3 leaf or 3.5 leaf stage) spraying (rice throwing or transplanting) After 3 to 5 days, the effect of weeds before the 1.5 leaf stage is the best), and the method of application is irrigation and spreading.
Dosage: Take 50% Mefenacet wettable powder as an example, 50-60 g/mu (seeding field/transplanting field in the southern region), 60-80 g/mu (transplanting field in the northern region). The effective dosage of barnyard grass varies depending on the leaf age: 1.5 leaves, 2.5 leaves, 3.5 leaves, and 4 leaves are respectively 500 g, 1 000 g, 1 500 g, and 2 000 g of active ingredients per hectare. The maintenance time of the drug effect in the paddy field varies according to the dosage: 30 days for 1 kg/hm² of active ingredient, 50 days for 1.5 kg/hm², 60 days for 2 kg/hm². The solubility of this agent in water is only 4 mg/L. It has strong soil adsorption and low penetration. Under normal paddy field conditions, most of the pesticide application amount is distributed within 1 cm of the surface layer, forming a treatment layer. The growth of seedlings should not come into contact with this layer. Mefenacet has excellent selectivity to transplanted rice.
The effective dosage of barnyardgrass depends on the leaf age: 1.5 leaves, 2.5 leaves, 3.5 leaves, and 4 leaves are 500g, 1000g, 1500g, and 2000g of active ingredients per hectare, respectively. The maintenance time of the drug effect in the paddy field varies with the dosage: the active ingredient is 1kg/hm230 days, 1.5kg/hm250 days, 2kg/hm260 days. The solubility of this agent in water is only 4mg/L. It has strong soil adsorption and low penetration. Under normal paddy field conditions, most of the pesticide application amount is distributed within 1cm of the surface layer, forming a treatment layer. The growth of seedlings should not come into contact with this layer. Benfenacet has excellent selectivity to transplanted rice.
Mefenacet (73250-68-7) uses
The herbicide Mefenacet is a cell production and division inhibitor with low toxicity. It is mainly used to control gramineous weeds. It is a highly active barnyard killer in rice fields and can kill barnyard grass before it occurs to the three-leaf stage. Effective against annual weeds and fescue. It has good selectivity for transplanted rice, has quick effect from before to the early stage of occurrence, and has a lasting effect of more than 30 days. The pesticide application method can be sprinkled with water.
Synthesis method of Mefenacet(73250-68-7)
1. Preparation of α-hydroxy-N-methylacetanilide: react anhydrous glycolic acid with acetyl chloride at 20-30°C, evaporate excess acetyl chloride at 90-100°C, add thionyl chloride dropwise after cooling, and heat to boiling , reacted for 3 hours, and purified by vacuum distillation to obtain acetoxyacetyl chloride with a yield of 70%; the product was reacted with N-methylaniline at 0-10°C in toluene solvent, and continued to react at 20°C for 15h to obtain Acetoxy-N-methylacetanilide, yield 74%; product Acetoxy-N-methylacetanilide was dissolved in methanol, added concentrated sodium hydroxide solution at 30°C, stirred at 20°C for 15h, After post-treatment, light yellow white crystalline α-hydroxy-N-methylacetanilide was obtained with a yield of 86%.
2-Chlorobenzothiazole can also be obtained by chlorinating benzothiazole in a pyridine solution in the presence of AlCl3 and POCl3.
2. Synthesis of Mefenacet
Add 2-chlorobenzothiazole to the dissolved sodium hydroxide and α-hydroxy-N-methylacetanilide at 20°C, react at 40-50°C for 2 hours, and obtain mefenacet after post-treatment, m.p.118 °C, the yield was 84%.
Precautions for use of mefenacet (73250-68-7)
1 This product is poisonous to fish, keep away from aquaculture areas for application, and it is forbidden to wash pesticide application equipment in water bodies such as rivers and ponds.
2 This product is highly toxic to algae, and special attention should be paid to avoid polluting the water system.
3 This product cannot be mixed with alkaline substances.
4. Pesticide applicators should wear anti-particle masks, protective clothing, protective rubber boots, gloves and other protective equipment; they should not smoke or drink water at this time; they should wash their hands and faces after applying pesticides.
5. Medical equipment must be washed after use; waste water from cleaning equipment cannot be discharged into rivers, ponds and other water sources. Waste must be properly disposed of and cannot be discarded at will or used for other purposes.
6. Avoid contact with pregnant and lactating women.
The price of the herbicide Mefenacet (73250-68-7)
Under normal circumstances, the price of the pesticide and herbicide fenacetate will be affected by raw materials, market environment, research and development costs, etc. If you want to know the latest price of the pesticide and herbicide phenylpropamide you need, please contact us to initiate an inquiry.
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Supplier of the herbicide Mefenacet(73250-68-7)
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