【CAS】：(3-phenoxyphenyl)methyl 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate
【CAS No.】：52645-53-1
【Molecular Formula】：C21H20Cl2O3

【Molecular weight】:391.3;

【Physical form】:Tech. is a yellow-brown to brown liquid, which sometimes tends to crystallise partly at room temperature.

【Density】:1.29 (20 °C);

【Melting point】:34-35 °C; cis- isomers 63-65 °C; trans- 44-47 °C;

【Flash point】:>100 °C ('Perigen');

【Vapour pressure】:cis- 0.0025 mPa; trans- 0.0015 mPa (both 20 °C) (D. Wells et al., Pestic. Sci., 1986, 17, 473);

【Partition coefficient(n-octanol and water)】:logP = 6.1 (20 °C);

【Solubility】:In water 6 × 10-3 mg/l ( pH 7, 20 °C). In xylene, hexane >1000, methanol 258 (all in g/ kg, 25 °C).;

【Stability】:Stable to heat (2 y at 50 °C), more stable in acidic than alkaline media with optimum stability c. pH 4; DT50 50 d ( pH 9), stable ( pH 5, 7) (all 25 °C).
【Toxicology】：ral:Oral LD50 values of permethrin depend on such factors as: carrier, cis/trans ratio of the sample, the test species, its sex, age and degree of fasting; values reported sometimes differ markedly. Values for a < Percutaneous:Acute percutaneous LD50 for rats >2500, rabbits >2000 mg/kg. Mild eye and skin irritant (rabbits). Moderate skin sensitiser. Inhalation: LC50 (3 h) for mice and rats >685 mg/m3 air; (separate study

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