Specification :

Fenthion

Common name: fenthion
IUPAC name: O, O-dimethyl O-4-methylthio-m-tolyl phosphorothioate
Chemical Abstracts name: O, O-dimethyl O-[ 3-methyl-4-( methylthio) phenyl] phosphorothioate
CAS RN: [ 55-38-9]
EEC no.: 200-231-9

PHYSICAL CHEMISTRY
Mol. wt.: 278.3; M.f.: C10H15O3PS2; Form: Colourless, oily liquid; ( tech., brown, oily liquid, with a mercaptan-like odour) . M.p.: No solidification point down to -80 ° C. B.p.: 90 ° C/ 1 Pa ( calc.) , 117 ° C/ 10 Pa ( calc.) , 284 ° C ( calc.) V.p.: 0.74 mPa ( 20 º C) ; 1.4 mPa ( 25 º C) . KOW: logP = 4.84; Henry: 5x10-2 Pa m3 mol-1 ( 20 ° C) . S.g./ density: 1.25 ( 20 º C) . Solubility: In water 4.2 mg/ l ( 20 º C) . In dichloromethane, toluene, isopropanol > 250, hexane 100 ( all in g/ l, 20 º C) . Stability: Stable to ligh, t and up to 210 º C. Relatively stable in acidic conditions, and moderately stable in alkaline conditions; DT50 ( 22 º C) 223 d ( pH 4) , 200 d ( pH 7) , 151 d ( pH 9) . F.p.: 170 º C ( tech.)

APPLICATIONS
Biochemistry: Cholinesterase inhibitor.
Mode of action: Insecticide with contact, stomach, and respiratory action.
Uses: Control of fruit flies, leafhoppers, leaf miners, leaf-eating larvae, stem borers, cereal bugs, and other insect pests in fruit ( including citrus) , vines, olives, vegetables, cotton, tea, sugar cane, rice, beet, tobacco, ornamentals, etc. For agricultural uses, application rates vary from 60 to 1200 g/ ha, depending on crop, pest, pest stage and application method. Control of insect pests ( flies, mosquitoes, cockroaches, fleas, ants, ticks, lice, etc.) in public health situations and animal houses, and control of animal ectoparasites.
Phytotoxicity: Non-phytotoxic when used as recommended. Some varieties of apples and cotton may be injured.
Formulation types: DP; EC; GR; HN; PO; UL; WP.
Compatibility: Incompatible with insecticides and fungicides which are highly alkaline.

MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for male and female rats c. 250 mg/ kg.
Skin and eye: Acute percutaneous LD50 ( 24 h) for male rats 586, female rats 800 mg/ kg; not irritating to skin and eyes ( rabbits) .
Inhalation: LC50 ( 4 h) for male and female rats c. 0.5 mg/ l air ( aerosol) .
NOEL: ( 2 y) for rats