Common name: Metsulfuron-methyl
Chemical Abstracts name:
methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoate
CAS RN:[74223-64-6]
PHYSICAL CHEMISTRY
Mol. wt.: 381.4
Form:Colourless crystals
M.p.: 158 ºC
V.p.: 3.3×10-7 mPa (25 ºC)
Kow logP= -1.74(pH 7)
Henry: 2.3×10-10 Pa m3 mol-1 (calc.)
S.g./density: 1.47
Solubility In water 0.55 (pH 5), 2.79 (pH 7), 213 (pH 9) (all in g/l, 25 ºC). In hexane 0.00079, xylene 0.58, ethanol 2.3, methanol 7.3, acetone 36, dichloromethane 121 (all in g/l, 20 ºC).
Stability Stable in air up to c. 140 ºC. Hydrolysis DT50 (25 °C), 22 d (pH 5), stable (pH 7 and 9)
TOXICOLOGY
Oral Acute oral LD50 for male and female rats >5000 mg/kg.
Skin and eye Acute percutaneous LD50 for rabbits >2000 mg/kg. Mild skin irritant to guinea pigs, but not a skin sensitiser; moderate but reversible eye irritant.
Inhalation LC50 (4 h) for male and female rats >5 mg/l air.
NOEL (2 y) for rats 500, male dogs 500, female dogs 5000 mg/kg diet.
ADI (JMPR) 0.25 mg/kg (Germany). Non-mutagenic in the Ames test. Non-teratogenic.
Toxicity class WHO (a.i.) III
EPA (formulation) IV
ECOTOXICOLOGY
Birds Acute oral LD50 for mallard ducks >5000 mg/kg. Dietary LC50 (8 d) for mallard ducks and bobwhite quail >5620 mg/kg diet.
Fish LC50 (96 h) for rainbow trout and bluegill sunfish >150 mg/l.
Daphnia EC50 (48 h) >150 mg/l.
Algae NOEC for green algae 100 mg/l.
Other aquatic spp. NOEC for Lemna gibba 0.16 mg/l.
Bees Non-toxic to bees; LD50 >25 mg/bee.
Worms >1000 mg/kg.
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