Title: Fenvalerate
CAS Registry Number: 51630-58-1
CAS Name: 4-Chloro-a-(1-methylethyl)benzeneacetic acid cyano(3-phenoxyphenyl)methyl ester
Additional Names: a-cyano-3-phenoxybenzyl a-(4-chlorophenyl)isovalerate; cyano(3-phenoxyphenyl)methyl 4-chloro-a-(1-methylethyl)benzeneacetate; a-cyano-3-phenoxybenzyl-2-(4-chlorophenyl)-3-methylbutyrate; phenvalerate
Manufacturers' Codes: S-5602; SD-43775; WL-43775
Trademarks: Belmark (Shell); Pydrin (Shell); Pyridin (DuPont); Sumicidin (Sumitomo); Tirade (Sumitomo)
Molecular Formula: C25H22ClNO3
Molecular Weight: 419.90
Percent Composition: C 71.51%, H 5.28%, Cl 8.44%, N 3.34%, O 11.43%
Literature References: Synthetic pyrethroid insecticide without the usual cyclopropane ring. Prepn: DE 2335347; K. Fujimoto et al., US 3996244 (1974, 1976, both to Sumitomo); D. A. Wood, DE 2651341; idem, US 4061664 (1977, both to Shell). Has two chiral centers giving four possible optical isomers; prepn and comparative insecticidal activity of isomers: M. Hirano et al., DE 2737297; eidem, US 4503071 (1978, 1985 both to Sumitomo). Absolute configuration of most active isomer, esfenvalerate: K. Aketa et al., Agric. Biol. Chem. 42, 895 (1978). GC separation of isomers: G. R. Cayley, B. W. Simpson, J. Chromatogr. 356, 123 (1986); determn of esfenvalerate in technical prepn: S. Sakaue et al., Agric. Biol. Chem. 51, 1671 (1987). Comprehensive description of activity and physical properties of esfenvalerate: H. Oo'uchi, Jpn. Pestic. Inf. 1985, 21-24. Comparative soil metabolism of isomers: P.W. Lee et al., J. Agric. Food Chem. 35, 384 (1987). Review of toxicology and human exposure: Toxicological Profile for Pyrethrins and Pyrethroids (PB2004-100004, 2003) 332 pp.
Properties: Clear yellow viscous liquid at 23°. d23 1.17. nD20 1.5533. Vapor press at 25° = 1.1´10-8 mm Hg. Soly at 20° (g/l): acetone, >450; chloroform, >450; methanol, >450; hexane, 77. Insol in water. More stable in acidic soln than in alk soln. Dec gradually between 150-300°. No significant breakdown after 100 hrs at 75°. LD50 orally in rats: 451 mg/kg (DMSO); >3200 mg/kg (aqueous suspension), Shell Technical Data Bulletin. Highly toxic to fish and bees.
Index of refraction: nD20 1.5533
Density: d23 1.17
Toxicity data: LD50 orally in rats: 451 mg/kg (DMSO); >3200 mg/kg (aqueous suspension), Shell Technical Data Bulletin
Derivative Type: (S,S)-Isomer
CAS Registry Number: 66230-04-4
Additional Names: Esfenvalerate; Aa
Manufacturers' Codes: OMS-3023; S-1844; S-5602a
Trademarks: Sumi-alpha (Sumitomo)
Properties: White crystalline solid, mp 59-60.2°. [a]D25 -15.0° (c = 2.0 in CH3OH). d2323 1.163. Vapor pressure at 20°: 2.63´10-7 mm Hg; at 25°: 5.00´10-7 mm Hg. Soly (1%): acetonitrile >60, chloroform >60, DMF >60, DMSO >60, ethyl acetate >60, acetone >60, ethyl cellosolve 40-50, n-hexane 1-5, kerosene <1, methanol 7-10, a-methylnaphthalene 50-60, xylene >60.
Melting point: mp 59-60.2°
Optical Rotation: [a]D25 -15.0° (c = 2.0 in CH3OH)
Density: d2323 1.163
CAUTION: Eye, skin irritant.
Use: Insecticide.
Therap-Cat-Vet: Ectoparasiticide.
Fepradinol Feprazone Ferbam Ferredoxins Ferric Acetate, Basic

Fenvalerate molecule
CAS number 51630-58-1 YesY
PubChem 3347
ChemSpider 3230 YesY
UNII Z6MXZ39302 YesY
KEGG C10988 YesY
RTECS number CY 1576350
ATCvet code QP53AC14,QP53AX02
Jmol-3D images Image 1
Molecular formula C25H22ClNO3
Molar mass 419.90 g mol−1
Appearance Yellow-brown viscous liquid
Density 1.175 g/cm3
Solubility in water 2 μg/L
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Fenvalerate is an insecticide. It is a mixture of four optical isomers which have different insecticidal activities. The 2-S alpha (or SS) configuration, known as esfenvalerate, is the most insecticidally active isomer. Fenvalerate consists of about 23% of this isomer.

Fenvalerate is an insecticide of moderate mammalian toxicity. In laboratory animals, central nervous system toxicity is observed following acute or short-term exposure. Fenvalerate has applications against a wide range of pests. Residue levels are minimized by low application rates. Fenvalerate is most toxic to bees and fish. It is found in some emulsifiable concentrates, ULV, wettable powders, slow release formulations, insecticidal fogs, and granules. It is most commonly used to control insects in food, feed, and cotton products, and for the control of flies and ticks in barns and stables. Fenvalerate does not affect plants, but is active for an extended period of time.

Fenvalerate may irritate the skin and eyes on contact, and is also harmful if swallowed.