BUTACHLOR

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

 

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.)

 

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.

 

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

 

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.

 

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.