IDENTIFICATION
Common name: Butachlor
Iupac name: N-butoxymethyl-2-chloro-2`,6`-diethylacetanilide
Chemical abstracts name: N-(butoxymethyl)-2-chloro-N-(2,6-diethylphenyl)acetamide
CAS RN: [23184-66-9]
M.F.: C17H26ClNO2
Mol Wt: 311.9
PHYSICAL CHEMISTRY
Type: Herbicide
Form (appearance): Light yellow to purple liquid with a faint, sweet odor.
M.P.: -2.8℃ to 1.7℃
B.P.: 156℃/0.5 mmHg
V.P.: 2.4 × 10-1 mPa (25℃)
F.P.: >135℃ (Tag closed cup)
Other properties Viscosity 37 cP (25℃)
S.G.: 1.076 (25℃)
Solubility.: In water 20 mg/l (20℃). Soluble in most organic solvents, including diethyl ether, acetone, benzene, ethanol, ethyl acetate, and hexane.
Stability: Decomposes at≥165 ℃. Stable to u.v. light. Stable indefinitely ≤45℃.
Henry: 3.74 ×10-3 Pa m3 mol-1 (calc.)
APPLICATION
Formulation types: EC; GR.
Biochemistry: Inhibits cell division by blocking protein synthesis.
Mode of action: Selective systemic herbicide, absorbed primarily by the germinating shoots, and secondarily by the roots, with translocation throughout the plant, giving higher concentrations in vegetative parts than in reproductive parts.
Uses:
Used pre emergence for the control of annual grasses and certain broadqeaved weeds in rice, both seeded and transplanted. It shows selectivity in barley, cotton, peanuts, sugar beet, wheat and several brassica crops. Effective rates range from 1.0 4.5 kg a.i./ha. Activity is dependent on water availability such as rainfall following treatment, overhead irrigation or applications to standing water as in rice culture.
MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats 2000, mice 4747, rabbits >5010 mg/kg
Skin and eye: Acute percutaneous LD50 for rabbits >13000 mg/kg. Moderate skin irritant: practically non-irritating to eyes (rabbits). Contact sensitisation reactions observed in guinea pigs.
Inhalation: LC50 (4 h) for rats >3.34 mg/l air.
Other Oncogenic in rats but not in mice. For detailed toxicology data, please contact Monsanto.
Toxicity: WHO (a.i.) III (Table 5); EPA (formulation) III
ECOTOXICOLOGY
Birds:Acute oral LD50 for mallard ducks >4640 mg/kg. Dietary LC50 (5 d) for mallard ducks >10000, bobwhite quail 6597 mg/kg diet.
Fish: LC50 (96 h) for rainbow trout 0.52, bluegill sunfish 0.44, carp 0.32, channel catfish 0.10-0.14, fathead minnow 0.31 mg/l.
Daphnia: LC50 (48 h) 2.4 mg/l. Other aquatic spp. LC50 (96 h) for crayfish 2-6 mg/l.
Worms: Bees: LD50 (contact) >100 μg/bee.
ENVIRONMENTAL FATE
Plant: Rapidly metabolised in plants to water soluble metabolites, leading eventually to mineralisation.
Animals: Metabolised to water soluble metabolites and excreted.
Soil/Environment: In soil, degradation is principally by microbial activity (Y.-L. Chen and T.-C. Wu, Nippon Noyaku Gakkaishi, 1978, 3, 411). Persists for c. 6 10 weeks. Converted in soil or water to water-soluble derivatives, with a slow evolution of CO2.
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