Benazolin-ethyl

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Chemical Identification | General Product Information | Physical & Safety Data

Chemical Identification

Common Name

Benazolin-ethyl

中文通用名

草除灵

IUPAC

ethyl 4-chloro-2,3-dihydro-2-oxo-1,3-benzothiazol-3-ylacetate

CAS

ethyl 4-chloro-2-oxo-3(2H)-benzothiazoleacetate

CAS No.

25059-80-7

Molecular Formula

C₁₁H₁₀ClNO₃S

Molecular Structure

General Product Information

Category

Herbicides > Benzothiazole herbicides

Activity

Herbicide

Physical & Safety Data

Physical Properties

Molecular weight:271.7; Physical form:White crystalline solid; tech. is pale yellow crystalline powder with a characteristic odour. Density:1.45 (20 °C); Melting point:79.2 °C; (tech., 77.4 °C); Vapour pressure:tech. 0.37 mPa (25 °C); Partition coefficient(n-octanol and water):logP = 2.50 (20 °C, in distilled water); Solubility:In water 47 mg/l (20 °C). In acetone 229, dichloromethane 603, ethyl acetate 148, methanol 28.5, toluene 198 (all in g/l, 20 °C).; Stability:Stable to at least 300 °C. Stable in acid and in neutral solution; at pH 9.18, DT50 7.6 d (25 °C). No significant breakdown in water in natural sunlight.

Toxicology

Oral:Acute oral LD₅₀ for mice >4000, rats >6000, dogs >5000 mg/kg. Percutaneous:Acute percutaneous LD₅₀ for rats >2100 mg/kg; not an irritant to skin and eyes of rabbits. Not a sensitiser. Inhalation:LC₅₀ (4 h) >5.5 mg/l. Low acute toxicity by inhalation route. ADI:0.006 mg/kg (dogs); 0.36 mg for a 60 kg human.

Environmental Profile

Ecotoxicology:
Algae:EC₅₀ for Selenastrum capricornutum 16.0 mg/l; NOEL 1.0 mg/l.Bees:10% EC formulation not harmful to bees.Birds:Acute oral LD₅₀ for bobwhite quail >6000, Japanese quail >9709, mallard ducks >3000 mg/kg. Dietary LC₅₀ (5 d) for bobwhite quail; Daphnia:LC₅₀(48 h) 6.2 mg/l. 21 d NOEC(immobilisation) 0.05 mg/l, (reproduction) 0.158 mg/l.Fish:LC₅₀(96 h) for bluegill sunfish 2.8, rainbow trout 5.4 mg/l. Worms:Low toxicity to earthworms: >1000 mg/kg dry soil.
Environmental fate:
Animals:Metabolism is by de-esterification of benazolin-ethyl to benazolin with a minor pathway involving opening of the thiazoline ring.Soil:On soil surface exposed to light, DT₅₀ 3.5 d. In soil, DT₅₀ 1-2 d. Benazolin-ethyl is degraded in soil by hydrolysis of the ester followed by a loss of the acetic acid side-chain, then ring opening; Plant:The major metabolite is benazolin acid.

Transport Information

Hazard Class:O (Obsolete as pesticide, not classified)