Herbicide safener
NOMENCLATURE
Common name dichlormid (WSSA)
IUPAC name N,N-diallyl-2,2-dichloroacetamide
Chemical Abstracts name 2,2-dichloro-N,N-di-2-propenylacetamide
CAS RN [37764-25-3] Development codes R-25788 (Stauffer)
PHYSICAL CHEMISTRY
Composition Tech. grade is c. 95% pure. Mol. wt. 208.1 M.f. C8H11Cl2NO Form Clear viscous liquid; (tech., amber-to-brown). M.p. 5.0-6.5 ºC (tech.) B.p. 130 °C/10 mmHg V.p. 800 mPa (25 ºC) KOW logP = 1.84.03 (25 ºC) S.g./density 1.202 (20 ºC); (tech., 1.192-1.204) Solubility In water c. 5 g/l. In kerosene c. 15 g/l. Miscible with acetone, ethanol, and xylene. Stability Unstable above 100 ºC. Decomposes violently if heated with iron. Stable to light.
COMMERCIALISATION
History Its use to enhance herbicidal selectivity reported by F. Y. Chang et al. (Can. J. Plant Sci., 1972, 52, 707). G. R. Stephenson (J. Agric. Food Chem., 1978, 26, 137) compared the chemical structure/biological activity of analogues. Introduced by the Stauffer Chemical Co. (now Syngenta AG). Patents US 4137070
APPLICATIONS
Mode of action See R. E. Wilkinson (Chemistry and Mode of Action of Herbicide Antidotes, p. 85); uptake by plant roots studied (R. A. Gray & G. K. Joo, ibid., p. 67). Uses Increases the tolerance of maize to thiocarbamate herbicides. Formulation types CG; CS; EC; GR; Liquid.
ANALYSIS
Product and residue analysis by capillary glc, details available from Syngenta.
MAMMALIAN TOXICOLOGY
Oral Acute oral LD50 for male rats 2816, female rats 2146 mg/kg. Skin and eye Acute percutaneous LD50 for rabbits >5000, rats >2000 mg/kg. Mild skin irritant; slightly irritating to eyes (rabbits). Mild skin sensitiser (guinea pigs). Inhalation LC50 (1 h) for rats >5.5 mg/l air. NOEL (2 y) for rats 7 mg/kg diet. Toxicity class WHO (a.i.) III EC hazard (Xi; R38)
ECOTOXICOLOGY
Birds Dietary LC50 (5 d) for mallard ducks 14 500, bobwhite quail >10 000 mg/kg diet. Fish LC50 (96 h) for rainbow trout 141 mg/l. Daphnia LC50 (48 h) 161 mg/l.
ENVIRONMENTAL FATE
Animals For metabolism in rats, see J. B. Miallis et al., Chemistry and Mode of Action of Herbicide Antidotes, p. 109. Plants For metabolism in maize, see idem, ibid. Soil/Environment In soil, DT50 c. 8 d (27-29 ºC). For degradation in soil, see idem, ibid. |
