| Name | brofenvalerate |
| Synonyms | BF 8900 brofenvalerate (R,S)-α-cyano-3(4'bropophenoxybenzyl)-(R,S)-2-(4-chlorophenyl)-3-methylbutyrate |
| Molecular Formula | C25H21BrClNO3 |
| Physical and Chemical Properties | Chemical properties The original drug is a dark amber oily liquid with 1.367 relative density and refractive index n24D1.5757. Soluble in organic solvents such as dimethyl sulfoxide and edible oil, insoluble in water. It is stable to light and heat, stable in acidic conditions, and easy to decompose under alkaline conditions. |
| Use | Use of pyrethroid insecticides. It has the characteristics of general pyrethroid pesticides, has good killing effect on a variety of pests, and low toxicity, and has the effect of controlling mites. Such as control of citrus aphids, citrus leaf moth, 20% ~ 1000 times with 2000 emulsifiable concentrate spray; Apple aphids with 2000~4000 times liquid spray; Cotton aphids, cotton bollworm, the dosage of cotton pink bollworm 75 ~ 150g active ingredient/hm2, that is, 20% ~ 750mL of 375 EC, 750 ~ 1000kg of water spray. Vegetable aphids in the initial peak period of aphids, the dosage of 30~45g active ingredient/hm2. |
residue
the study on the residual amount of brommethrin on citrus showed that the biological half-life on citrus was about 21 days, and the residual amount of citrus was related to the application amount and the application times, and increased with the increase of the application amount and times. 20% emulsifiable concentrate 1:2000 times was used for prevention and control 4 times a year. Brommethrin residue in citrus fruit was below 0.Zpm during harvest, mainly in citrus peel, and was not detected in clean meat. According to the maximum residue limit of fenvalerate is 2 mg/kg as a control, the residues of brommethrin in citrus fruit and orange peel are within the safe range.
production method
For the preparation of α-cyano-3-(4 '-bromophenoxy) benzyl alcohol, see the preparation method of bromfluthrin.
The preparation of α-isopropyl p-chlorophenylacetic acid uses p-chlorotoluene as a raw material, chlorinated its side chain to prepare p-chlorobenzyl, and then reacts with sodium cyanide in the presence of a phase transfer catalyst to generate p-chlorobenzyl. p-chlorobenzyl is alkylated with 2-chloropropane in the presence of a phase transfer catalyst and sodium hydroxide, and then hydrolyzed with 65% sulfuric acid to obtain α-isopropyl p-chlorophenylacetic acid, or 3-Methyl -2-(p-chlorophenyl) butyric acid.
The synthesis of dethrin first reacts α-isopropyl p-chlorophenylacetic acid with SOCl2 to obtain the corresponding acid chloride. Then, the reaction of α-cyanide -3-(4 '-bromophenoxy) benzyl alcohol with α-isopropyl p-chlorophenyl chloride was used to prepare bromethrin.