IDENTIFICATION
Common name: Esfenvalerate
Iupac name: ( S)-ot-cyano-3-phenoxybenzyl ( S)- 2-( 4-chlorophen yl)-3-meth ylbutyrate.
Chemical abstracts name: [S_(R*,R*)]-cyano(3-phenoxyphenyl)methyl 4-chloro-2-(1- methylethyl) benzeneacetate
Type: Insecticide for Agriculture
CAS RN: [66230-04-4]
M.F.: C25H22ClNO3
Mol Wt: 419.9
PHYSICAL CHEMISTRY
Form (appearance): Colourless crystals; (tech., yellow-brown viscous liquid or solid at 23℃).
Composition:: Tech. is ≥98% total isomers and ≥75% resolved (S,S)-isomers.
M.P.: 59.0-60.2℃; (tech., 43.3-54℃)
B.P.: 151-167℃ (tech.)
V.P.: 2 × 10-4 mPa (25℃)
F.P.: 256℃ (Pensky-Martens)
S.G.: 1.26 (4-26℃)
Solubility: In water 0.002 mg/l (25℃). In xylene, acetone, chloroform, ethyl acetate, dimethylformamide, dimethyl sulfoxide >600, hexane 10-50, methanol 70-100 (all in g/kg, 25℃).
Stability: Relatively stable to heat and light. Stable to hydrolysis at pH 5, 7 and 9 (25℃). Specific rotation [℃] 25D -15.00 (c 2.0 in methanol)
Henry: 4.20 × 10-2 Pa m3 mol-1 (calc.)
KowlogP: 6.22 (25℃)
APPLICATION
Formulation types: EC; SC; UL
Biochemistry: Voltage dependent sodium channel agonist.
Mode of action: Insecticide with contact and stomach action
Uses: A potent contact and ingested insecticide with a very broad range of activity, especially effective against Coleoptera, Diptera, Hemiptera, Lepidoptera and Orthoptera on cotton, fruit, vegetables and other crops, at 5-25 g a.i./ha. It is effective against strains resistant to organochlorine, organophosphorus and carbamate insecticides. Phytotoxicity Some injury has been noted on crucifers, cucumbers, aubergines, tomatoes, pears and mandarin oranges
MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats 75-88 mg/kg.
Skin and eye: Acute percutaneous LD50 for rats >5000, rabbits >2000 mg/kg. Slight skin irritant; mild eye irritant. Not a skin sensitiser.
Noel: No effect on sub-chronic studies at ≥2 mg/kg daily.
ADI: 0.02 mg/kg.
Other Acute LD50 values vary with the vehicle, concentration, route and species, etc.; values reported sometimes differ markedly. No carcinogenic, developmental or reproductive toxicity in animal tests.
Toxicity: WHO (a.i.) II; EPA (formulation) II
EC hazard: T; R23/25| R43| N; R50, R53
ECOTOXICOLOGY
Birds: Acute oral LD50 for bobwhite quail 381 mg/kg. LC50 (8 d) for bobwhite quail >5620, mallard ducks 5247 ppm.
Fish: Extremely toxic to aquatic animals. LC50 (96 h) for fathead minnow 0.690, bluegill sunfish 0.26, rainbow trout 0,26 μg/t.
Daphnia: LC50 (48 h) 0.24 μg/l.
Worms: /Bees: LD50 (contact) 0.017 μg/bee.
ENVIRONMENTAL FATE
Plant: The major metabolite was decarboxylated fenvalerate. Ester cleavage, hydration of the cyano group to carboxamide and carboxylic acid, hydroxylation of the 2`- and 4`-phenoxy positions, conversion of the alcohol moiety to 3-phenoxybenzyl alcohol and 3- phenoxybenzoic acid, and conjugation of the resulting carboxylic acids and alcohols with sugars, also occur.
Animals: Rapid metabolism and elimination occurs in rats and other animals. Primary metabolism involves hydroxylation of 2`- and 4`- hydroxyl moieties, ester cleavage, hydroxytation and oxidation of the alcohol derivatives, oxidation of the cyano moiety and conjugation of the acidic metabolites with sulfate, glycine and glucuronic acid.
Soil/Environment: In sand (0.38% o.m.), Kd (25℃) 4.4; in sandy loam (pH 7.3, 1.1% o.m.), Kd (25℃) 6.4, DT50 88 d; in silty loam (pH 5.3, 2.0% o.m.), Kd (25℃) 71, DT50 114 d; in clay loam (pH 5.7, 0.2% o,m.), DT50 287 d; in clay loam (pH 6.4, 1.5% o.m.), Kd (25℃) 105. Koc 5300. |
