ALACHLOR

Common name: Alachlor

Chemical name: 2-chloro-2 ′ ,6 ′ -diethyl- N -methoxymethylacetanilide

Structural formula:

Chemical class: Chloroacetanilide herbicide

CAS No.: 15972-60-8

Properties: Technical product is yellow to red solid (at room temperature). M.p. 40.5-41.5 ℃ ; B.p. 100 ℃ /0.0026 kPa; V.p. 2.1 mPa (25 ℃ ); Soluble in water 242mg/L (25 ℃ ). Soluble in diethyl ether, acetone, benzene, chloroform, ethanol, and ethyl acetate. Slightly soluble in heptane; Hydrolysed by strong acids and alkalis. Stable to u.v. light. Decomposes at 105 ℃ . F.p. 137 ℃ (closed cup); 160 ℃ (open cup).

Toxicity: Acute oral LD 50 for rats 930-1350 mg/kg. Acute percutaneous LD 50 for rabbits 13,300mg/kg. Non-irritating to skin or eyes (rabbits). Contact sensitization reactions observed in guinea pigs. Inhalational LC 50 (4 h) for rats 1.04 mg/L air.

Ecotoxicology: Birds, Acute oral LD 50 for bobwhite quail 1536 mg/kg. LC 50 (5 d) for mallard ducks and bobwhite quail ﹥ 5620 mg/kg diet. Fish, LC 50 (96 h) for rainbow trout 1.8, bluegill sunfish 2.8, fathead minnow 5.0, channel catfish 2.1 mg/L. Bees, not hazardous to bees when used as directed; LD 50 32 mg/bee. Worms, LC 50 (14 d) for earthworms 387 mg/kg dry soil. Daphnia, EC 50 (48 h) 10 mg/L.

Environmental fate: Animals, rapidly oxidized by rat liver microsomal oxygenases to 2,6-diethylaniline. Plants, rapidly metabolized in plants to 2-chloro-2',6'-diethylacetanilide, with further degradation to the aniline derivative. Soil/Environment, rapidly degraded in soil by microbial action to 2-chloro-2',6'-diethylacetanilide, with further degradation to the aniline derivative; DT 50 1-30 d. persists in soil for c. 6-10 w. in surface water, 55% degraded in 28 d.

Treatment: Get medical aid. Eyes, flush with water. Skin, wash with plenty of soap and water. Ingestion, induce vomiting as directed by medical personnel.

Mode of action: Selective systemic herbicide, absorbed principally by germinating shoots, but also by the roots, with translocation throughout the plant, and accumulation mainly in vegetative parts rater than in reproductive parts.

Usage: Used pre-emergence at 1.68-4.48 kg/ha to control annual grasses and many broad-leaved weeds in cotton, brassicas, maize, oilseed rape, peanuts, radish, soya beans and sugar cane.