Common name: empenthrin; empenthrine

IUPAC name: (E)-(RS)-1-ethynyl-2-methylpent-2-enyl (1R,3RS;1R,3SR)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate

Roth: (E)-(RS)-1-ethynyl-2-methylpent-2-enyl (1R)-cis-trans-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate

Chemical Abstracts name: 1-ethynyl-2-methyl-2-pentenyl (1R)-cis-trans-2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate

CAS RN: [54406-48-3] unstated stereochemistry

EEC no.: 259-154-4

 

Composition: The name empenthrin is defined for the (E)-(RS) (1RS)-cis-trans- mixed isomers. However, the material in use is the (EZ)-(RS) (1R)- rich cis-trans- isomer mixture. Mol. wt.: 274.4; M.f.: C18H26O2. Form: Yellow liquid. B.p.: 295.5 ºC/760 mmHg. V.p.: 14 mPa (23.6 ºC). S.g./density: 0.927 (20 ºC). Solubility: In water 0.111 mg/l (25 ºC). Totally miscible in hexane, acetone and methanol (20 ºC). Stability: Stable under normal conditions for at least 2 years. F.p.: 107 °C.

 

Mode of action: Insecticide with contact action. Compared with other pyrethroids, has a high vapour pressure and hence is active against flying insects.

Uses: Used as a domestic insecticide, especially against moths, woolly bears and other insects attacking fabrics.

Formulation types: Aerosol; Impregnated material.

Compatibility: Not compatible with alkaline materials.

 

Oral: Acute oral LD50 for male rats >5000, female rats >3500 mg/kg.

Skin and eye: Acute percutaneous LD50 for rats >2000 mg/kg. Not irritating to skin; minimal irritation to eyes (rabbits).

Inhalation: LC50 (4 h) for rats >4610 mg/m3.

Toxicity class: WHO (a.i.) III

 

Birds: Acute oral LD50 for bobwhite quail and mallard ducks >2250 mg/kg. Dietary LC50 for bobwhite quail and mallard ducks >5620 ppm.

Fish: LC50 (96 h) for rainbow trout 0.0017 mg/l.

Daphnia EC50 (48 h) 0.02 mg/l.