IDENTIFICATION
Common name: Triasutfuron
Other name: triasutfuron (BSI, draft E-ISO, (m) draft F-ISO)
Iupac name: 1-[2-(2-chloroethoxy)phenylsulfonyl]-3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)urea
Chemical abstracts name: 2-(2-chloroethoxy)-N-[[(4-methoxy-6-methyl-1,3.5-triazin-2-yl)amino]carbonyl]benzenesulfonamide
Type: Herbicide
CAS RN: [82097-50-5]
M.F.: C14H16ClN5O5S
Mol Wt: 401.8
PHYSICAL CHEMISTRY
Form (appearance): Fine white powder.
M.P.: 178.1℃ (decomp.)
V.P.: <2 × 10-3 mPa (25℃) (OECD 104)
S.G.: 1.5 g/cm3
Solubility.: In water 32 (pH 5), 815 (pH 7), 13500 (pH 8.4) (all in mg/l, 25℃). In acetone 14, dichloromethane 36, ethyl acetate 4.3 (all in g/l, 25℃). In ethanol 420, n- octanol 130, n-hexane 0.04, toluene 300 (all in mg/l, 25℃).
Stability: Stable for more than 2 years under normal storage conditions. Partial decomposition below the melting point. On hydrolysis, DT50 8.2 h (pH 1), 3.1 y (pH 7), 4.7 h (pH 10).
Henry: <8 × 10-5 Pa m3 mol-1 (calc.)
KowlogP: 1.1 (pH 5.0), -0.59 (pH 6.9), -1.8 (pH 9.0) (25℃)
Pka: 4.64 (2050)
APPLICATION
Formulation types: WG.
Biochemistry: Branched chain amino acid synthesis (ALS or AHAS) inhibitor. Acts by inhibiting biosynthesis of the essential amino acids valine and isoteucine, hence stopping cell division and plant growth. Selectivity derives from rapid metabolism in the crop. Metabolic basis of selectivity in sulfonylureas reviewed (M. K. Koeppe & H. M. Brown, Agro Foodlndustry, 6, 9-14 (1995)).
Mode of action: Selective herbicide, absorbed by the leaves and roots, and rapidly translocated to meristems.
Uses: Control of broadqeaved weeds pre- and post-emergence in wheat, barley and triticale, at 5-10 g/ha.
MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50for rats and mice >5000 mg/kg.
Skin and eye: Acute percutaneous LD50 for rats >2000 mg/kg. Mild skin irritant: non-irritating to eyes (rabbits). Non-sensitising to skin (guinea pigs).
Inhalation: LC50 (4 h) for rats >5.J8 mg/l air.
Noel: (2 y) for rats 32.1 mg/kg b.w. daily, for mice 1.2 mg/kg b.w. daily; (1 y) for dogs 33 mg/kg b.w. daily.
ADI: 0.012 mg/kg b.w.
Toxicity: WHO (a.i.) III (Table 5); EPA (formulation) IV
ECOTOXICOLOGY
Birds: Acute oral LD50 for quail and ducks >2150 mg/kg.
Fish: LC50 (96 h) for rainbow trout, carp, catfish, sheepshead minnow and bluegill sunfish >100 mg/1.
Daphnia: LC50 (96 h) >100 mg/l.
Algae: EC50 (5-14 d) for Selenastrum 0.035, Scenedesmus 0.77, Anabaena 1.7, Navicula >100 mg/l.
Other aquatic spp. EC50 (48 h) for Quahog clam 56 mg/l.
Worms: LC50 (14 d) for earthworms >1000 mg/kg soil.
/Bees: Non-toxic to honeybees. LD50 (acute and contact) >100/μ/bee.
ENVIRONMENTAL FATE
Plant: In wheat, metabolism is by hydroxylation (para to the sulfonyl urea bridge), followed by conjugation of various hydroxy metabolites with glucose. DT50 in forage c. 3 d. In straw and grain, no residues were detectable at harvest time.
Animals: Mainly excreted in the urine in unchanged form.
Soil/Environment: The degradation behaviour in soil is determined by the soil type, pH, and especially temperature and moisture content. Field studies with silty loam, clay loam and sandy loam showed a median DT50 19 d, depending on soil type.
|
