Common name: Chlorothalonil
IUPAC name: tetrachloroisophthalonitrile
Chemical Abstracts name:2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile
CAS RN:[1897-45-6]
PHYSICAL CHEMISTRY
Mol. wt.: 265.9
Form: Colourless, odourless crystals; (tech. has a slightly pungent odour).
M.p.: 252.1 °C
B.p.: 350 ºC/760 mmHg
V.p.: 0.076 mPa (25 ºC)
Kow logP = 2.92 (25 °C)
Henry:2.50×10-2 Pa m3 mol-1 (25 °C)
S.g./density: 2.0 (20 °C)
Solubility In water 0.81 mg/l (25 ºC). In xylene 80, cyclohexanone, dimethylformamide 30, acetone, dimethyl sulfoxide 20, kerosene <10 (all in g/kg, 25 ºC).
Stability Thermally stable at ambient temperatures. Stable to u.v. light in aqueous media and in crystalline state. Stable in acidic and moderately alkaline aqueous solutions; slow hydrolysis at pH >9.
TOXICOLOGY
Oral Acute oral LD50 for rats >5000 mg/kg.
Skin and eye Acute percutaneous LD50 for albino rabbits >10 000 mg/kg. Severe eye irritant; mild skin irritant (rabbits). Evidence in humans of contact dermatitis.
Inhalation LC50 (1 h) for rats >4.7 mg/l air; (4 h) for rats (nominal concentration) 0.6 mg/l air; (4 h) for rats (actual) 0.10 mg/l air.
NOEL Chronic administration of chlorothalonil has been associated with tumour formation in the kidney and forestomach of rats and male mice. The mechanism has been demonstrated to be epigenetic with a NOEL of 1.8 in rats and 1.6 in mice. In dogs, the pattern of toxicity is different from that in rodents, with a NOEL of at least 3 mg/kg b.w. (JMPR 1990).
ADI (JMPR) 0.03 mg/kg
Toxicity class WHO (a.i.) III
EPA (formulation) II
EC hazard Xn; R40
ECOTOXICOLOGY
Birds Acute oral LD50 for mallard ducks >4640 mg/kg. Dietary LC50 (8 d) for mallard ducks and bobwhite quail >10 000 mg/kg diet.
Fish LC50 (96 h) for rainbow trout 47, bluegill sunfish 60, channel catfish 43 mg/l.
Daphnia LC50 (48 h) 70 mg/l.
Algae For Selenastrum capricornutum, EC50 (120 h) 0.21 mg/l, NOEC (120 h) 0.1 mg/l.
Other aquatic spp. LC50 (96 h) for pink shrimp 165 mg/l.
Bees No more than slightly toxic.
Worms LC50 (14 d) >1000 mg/kg.
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