Fenthion

Fenthion

倍硫磷

O,O-dimethyl O-4-methylthio-m-tolyl phosphorothioate

O,O-dimethyl O-[3-methyl-4-(methylthio)phenyl] phosphorothioate

55-38-9

C₁₀H₁₅O₃PS₂

Insecticides > Organophosphorus insecticides

Insecticide

Molecular weight:278.3; Physical form:Colourless, oily liquid; ( tech., brown, oily liquid, with a mercaptan-like odour). Density:1.25 (20 °C); Melting point:No solidification point down to -80 °C; Flash point:170 °C ( tech.); Vapour pressure:0.74 mPa (20 °C); 1.4 mPa (25 °C); Henry constant:5 × 10-2 Pa m3 mol-1 (20 °C); Partition coefficient(n-octanol and water):logP = 4.84; Solubility:In water 4.2 mg/l (20 °C). In dichloromethane, toluene, isopropanol >250, hexane 100 (all in g/l, 20 °C).; Stability:Stable to ligh,t and up to 210 °C. Relatively stable in acidic conditions, and moderately stable in alkaline conditions; DT50 (22 °C) 223 d ( pH 4), 200 d ( pH 7), 151 d ( pH 9).;

Oral:Acute oral LD₅₀ for male and female rats c. 250 mg/ kg. Percutaneous: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). Phytotoxicity:Non-phytotoxic when used as recommended. Some varieties of apples and cotton may be injured. ADI:( JMPR) 0.01 mg/ kg b.w. [1995].

Ecotoxicology:
Algae: E_rC₅₀ for Scenedesmus subspicatus 1.79 mg/l.Bees:Toxic to bees.Birds:Acute oral LD₅₀ for bobwhite quail 7.2 mg/kg. Dietary LC₅₀ (5 d) for bobwhite quail 60, mallard ducks 1259 mg/ kg.Daphnia: LC₅₀ (48 h) 0.0057 mg50 (96 h) for bluegill sunfish 1.7, rainbow trout 0.8-1.0, golden orfe 2.7 mg/l.Worms: LC₅₀ for Eisenia foetida 375 mg/ kg dry soil. 

Environmental fate: 
Animals:In mammals, following oral administration, elimination is mainly in the form of hydrolysis products in the urine. Major metabolites are fenthion sulfoxide, fenthion sulfone and their oxygen analogues. These metabolites are hydrolysed in further degradatioSoil: K_oc 1500 (Ware, Rev. Environ. Contam. Toxicol., 123 (1992)). In sediment/water system with and without plants, DT₅₀ is c. 1.5 d (O'Neill et al.,Plant:In plants, fenthion is oxidised to the sulfoxide and sulfone, both of which possess insecticidal properties, and to the monodesmethyl compound of fenthion sulfoxide. Further degradation occurs to the sulfone phosphate, which undergoes hydrolysis.

Signal Word:WARNING; Hazard Class:II(Moderately hazardous)