Common name: tetramethrin; tétraméthrine; phthalthrin
IUPAC name: cyclohex-1-ene-1,2-dicarboximidomethyl (1RS,3RS;1RS,3SR)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate
Alt: cyclohex-1-ene-1,2-dicarboximidomethyl (?-cis-trans-chrysanthemate
Roth: cyclohex-1-ene-1,2-dicarboximidomethyl (1RS)-cis-trans-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate
3,4,5,6-tetrahydrophthalimidomethyl (-cis-trans-chrysanthemate
Chemical Abstracts name: (1,3,4,5,6,7-hexahydro-1,3-dioxo-2H-isoindol-2-yl)methyl 2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate
CAS RN: [7696-12-0]
IUPAC name: cyclohex-1-ene-1,2-dicarboximidomethyl (1RS,3RS;1RS,3SR)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate
Alt: cyclohex-1-ene-1,2-dicarboximidomethyl (?-cis-trans-chrysanthemate
Roth: cyclohex-1-ene-1,2-dicarboximidomethyl (1RS)-cis-trans-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate
3,4,5,6-tetrahydrophthalimidomethyl (-cis-trans-chrysanthemate
Chemical Abstracts name: (1,3,4,5,6,7-hexahydro-1,3-dioxo-2H-isoindol-2-yl)methyl 2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate
CAS RN: [7696-12-0]
PHYSICAL CHEMISTRY
Composition: Tech. is c. 95% pure. Mol. wt.: 331.4; M.f.: C19H25NO4; Form: Colourless crystals, with slight pyrethrum-like odour; (tech. is a colourless to light yellow-brown solid). M.p.: 68-70 °C; (tech., 60-80 ºC). V.p.: 2.1 mPa (25 °C). KOW: logP = 4.6 (25 ºC). S.g./density: 1.1 (20 ºC). Solubility: In water 1.83 mg/l (25 ºC). In acetone, ethanol, methanol, hexane, n-octanol all >2 g/100 ml. Stability: Sensitive to alkalis and strong acids; DT50 16-20 d (pH 5), 1 d (pH 7), <1 h (pH 9). Stable on storage up to c. 50 ºC. Stable in ketones, chloroform, xylene, common aerosol propellants, etc. Variable stability with inorganic carriers. F.p.: 200 °C (Cleveland open cup).
APPLICATIONS
Mode of action: Non-systemic insecticide with contact action. Gives rapid knockdown.
Uses: Normally used in combination with synergists (e.g. piperonyl butoxide) and other insecticides for control of flies, cockroaches, mosquitoes, wasps, and other insect pests in public health and home and garden use.
Formulation types: AE; DP; EC; EW; OE; UL; Oil.
Compatibility: Incompatible with mineral carriers such as kieselguhr, acidic clays and kaolin.
MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats >5000 mg/kg.
Skin and eye: Acute percutaneous LD50 for rabbits >2000 mg/kg. Non-irritant to skin.
Inhalation: LC50 (4 h) for rats >2.73 mg/l air.
NOEL: In 13 w feeding trials, dogs receiving 5000 mg/kg diet showed no ill-effects. In 6 mo feeding trials, no-effect level for rats was 1500 mg/kg diet.
Other: No evidence of oncogenicity.
Toxicity class: WHO (a.i.) III (Table 5); EPA (formulation) IV
ECOTOXICOLOGY
Birds: Acute oral LD50 for bobwhite quail >2250 mg/kg. Dietary LC50 for bobwhite quail and mallard ducks >5620 ppm.
Fish: LC50 (96 h) for rainbow trout 3.7, bluegill sunfish 16 ug/l.
Daphnia: EC50 (48 h) 0.11 mg/l.
Bees Toxic to bees.
Birds: Acute oral LD50 for bobwhite quail >2250 mg/kg. Dietary LC50 for bobwhite quail and mallard ducks >5620 ppm.
Fish: LC50 (96 h) for rainbow trout 3.7, bluegill sunfish 16 ug/l.
Daphnia: EC50 (48 h) 0.11 mg/l.
Bees Toxic to bees.
ENVIRONMENTAL FATE
Animals: In rats, following oral administration, around 95% of tetramethrin (metabolised) is eliminated in the urine and faeces within 5 days. The principal metabolite is 3-hydroxycyclohexan-1,2-dicarboximide.
Soil/Environment: Degradation involves cleavage of the ester bond, leading to chrysanthemic acid derivatives and phenoxybenzoic acid. These are further metabolised by hydroxylation and conjugation.
