Terbacil

Favorites

Chemical Identification | General Product Information | Physical & Safety Data

Chemical Identification

Common Name

Terbacil

中文通用名

特草定

IUPAC

3-tert-butyl-5-chloro-6-methyluracil

CAS

5-chloro-3-(1,1-dimethylethyl)-6-methyl-2,4(1H,3H)-pyrimidinedione

CAS No.

5902-51-2

Molecular Formula

C₉H₁₃ClN₂O₂

Molecular Structure

General Product Information

Category

Herbicides > Uracil herbicides

Activity

Herbicide

Physical & Safety Data

Physical Properties

Molecular weight:216.7; Physical form:Colourless crystals. Density:1.34 (25 °C); Composition:Tech. is 97%. Melting point:175-177 °C; Vapour pressure:0.0625 mPa (29.5 °C); Henry constant:1.3 × 10-5 Pa m3 mol-1 ( calc.); Partition coefficient(n-octanol and water):logP = 1.91; pKa:9.5; Solubility:In water 710 mg/l (25 °C). In dimethylformamide 337, cyclohexanone 220, methyl isobutyl ketone 121, butyl acetate 88, xylene 65 (all in g/kg, 25 °C). Sparingly soluble in mineral oils and aliphatic hydrocarbons. Readily s; Stability:Very stable, even at m.p. Stable in aqueous alkaline media at room temperature. Stable 31 d in the dark in aqueous solution (c. pH 6, 25 °C), and in an aqueous solution containing 0.05 M ferric chloride (c

Toxicology

Oral:Acute oral LD₅₀ for rats 934 mg/kg. Percutaneous:Acute percutaneous LD₅₀ for rabbits >2000 mg/kg. Mild eye irritant; slight skin irritant. Not a skin sensitiser. Inhalation: LC₅₀ (4 h) for rats >4.4 mg/l.

Environmental Profile

Ecotoxicology:
Bees:Non-toxic to bees.Birds:Dietary LC₅₀ (8 d) for Pekin ducklings >56 000, pheasant chicks >31 450 mg/kg diet.Daphnia: LC₅₀ (48 h) 68 ppm.Fish: LC₅₀ (96 h) for rainbow trout 46.2 mg/l.Other aquatic spp.: LC₅₀ (48 h) for fiddler crab >1000 mg/l.

Environmental fate:
Animals:The principal biotransformation pathways are hydroxylation of the 6-methyl group, and replacement of the 5-chloro group with a hydroxy group (B. C. Mayo et al., Proc. Br. Crop Prot. Conf. - Pests Dis., 1988, 2, 6Soil:Undergoes microbial decomposition in moist soil. In top soil, 50% still remains 5-7 months after applying 4.5 kg/ha (P. B. Marriage, Weed Res., 1977, 17, 219-225).Plant:In alfalfa, 12% of terbacil plus its metabolites are still found 6-8 months after application (R. F. Holt & H. L. Pease, J. Agric. Food Chem., 1977, 25, 373).

Transport Information

Hazard Class:III(Slightly hazardous)