Specification :

Alpha-Cypermethrin

Common name: alpha-cypermethrin; alpha-cypermé thrine
IUPAC name: A racemate comprising ( S) -a-cyano-3-phenoxybenzyl ( 1R, 3R) -3-( 2, 2-dichlorovinyl) -2, 2-dimethylcyclopropanecarboxylate and ( R) -a-cyano-3-phenoxybenzyl ( 1S, 3S) -3-( 2, 2-dichlorovinyl) -2, 2-dimethylcyclopropanecarboxylate
Roth: A racemate comprising ( S) -a-cyano-3-phenoxybenzyl ( 1R) -cis-3-( 2, 2-dichlorovinyl) -2, 2-dimethylcyclopropanecarboxylate and ( R) -a-cyano-3-phenoxybenzyl ( 1S) -cis-3-( 2, 2-dichlorovinyl) -2, 2-dimethylcyclopropanecarboxylate
Chemical Abstracts name: [ 1a( S* ) , 3a] -( ? -cyano( 3-phenoxyphenyl) methyl 3-( 2, 2-dichloroethenyl) -2, 2-dimethylcyclopropanecarboxylate
Other names: alfoxylate* ; alphamethrin* ( rejected common name proposals)
CAS RN: [ 67375-30-8] correct stereochemistry; [ 52315-07-8] ( formerly [ 86752-99-0] , [ 86753-92-6] ) cypermethrin ( no stereochemistry stated) were sometimes used in Chemical Abstracts.

PHYSICAL CHEMISTRY
Composition: Tech. grade alpha-cypermethrin is > 90% pure m/ m, typically > 95% . Mol. wt.: 416.3; M.f.: C22H19Cl2NO3; Form: Colourless crystals; ( tech. is a white to pale powder, with a weak aromatic odour) ; M.p.: 78-81 º C; B.p.: 200 º C/ 9.3 Pa; V.p.: 2.3x10-2 mPa ( 20 º C) ; KOW: logP = 6.94 ( pH 7) ; Henry: 6.9x10-2 Pa m3 mol-1 ( calc.) S.g./ density: 1.28 ( 22 º C) ; Solubility: In water c. 0.01 mg/ l ( 25 º C) . In acetone 620, dichloromethane 550, cyclohexanone 515, ethyl acetate 440, chlorobenzene 420, acetophenone 390, o-xylene 350, hexane 7 ( all in g/ l, 25 º C) . In maize oil 19-20, ethylene glycol 80 º C ( closed cup) .

APPLICATIONS
Mode of action: Non-systemic insecticide with contact and stomach action. Acts on the central and peripheral nervous system in very low doses.
Uses: Control of a wide range of chewing and sucking insects ( particularly Lepidoptera, Coleoptera, and Hemiptera) in fruit ( including citrus) , vegetables, vines, cereals, maize, beet, oilseed rape, potatoes, cotton, rice, soya beans, forestry, and other crops. Control of cockroaches, mosquitoes, flies, and other insect pests in public health; and flies in animal houses. Also used as an animal ectoparasiticide.
Formulation types: EC; SC; TB; UL; WP.
Compatibility: Compatible with most organophosphorus insecticides.

MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats 79-400 mg/ kg ( in corn oil, value depending on concentration) , 474 mg tech./ kg.
Skin and eye: Acute percutaneous LD50 for rats and rabbits > 2000 mg tech./ kg; minimal irritant to the eyes of rabbits.
Inhalation: LC50 ( 4 h) for rats 0.32 mg/ l air.
NOEL: In 90 d feeding trials, rats receiving 60 mg/ kg diet showed no ill-effects.
ADI: 0.02 mg/ kg b.w.
Other: Non-mutagenic.
Toxicity class: WHO ( a.i.) II; EPA ( formulation) II

ECOTOXICOLOGY
Birds: LD50 for quail and mallard ducks > 10 000 mg/ kg.
Fish: LC50 ( 96 h) for rainbow trout 0.0028 mg/ l; due to rapid loss from water, no toxic effect to fish is observed under field conditions.
Daphnia: LC50 ( 48 h) 0.1-0.3 g/ l.
Bees: Toxic to bees. LD50 ( 24 h) 0.059 g/ bee. No toxic effect under field conditions.
Worms: LD50 ( 14 d) for earthworms > 100 mg/ kg artificial soil.

ENVIRONMENTAL FATE
EHC: EHC 142 notes that, although highly toxic to fish, this is not realised under field conditions where rapid loss from water allows recovery of affected populations.
Animals: See cypermethrin.
Soil/ Environment: Undergoes degradation in soil, DT50 c. 13 w in loamy soil.