DDT

DDT

滴滴涕

1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane

1,1′-(2,2,2-trichloroethylidene)bis[4-chlorobenzene]

50-29-3

C₁₄H₉Cl₅

Insecticides > Organochlorine insecticides
Acaricides / Miticides > Organochlorine acaricides
Acaricides / Miticides > Bridged diphenyl acaricides

Insecticide

Molecular weight:354.5; Physical form:Colourless crystals (pp'-DDT); ( tech., a waxy solid). Density:1.56 (15 °C); Composition:Tech. product contains 30% op'-DDT [1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane] which, being of insecticidal value, is not usually removed. Melting point:Indefinite ( tech.); 108.5-109 °C (pp'-DDT); Vapour pressure:0.025 mPa (20 °C; pp'-DDT); Solubility:Practically insoluble in water. Readily soluble in aromatic and chlorinated solvents; moderately soluble in polar organic solvents and petroleum oils. In cyclohexanone 1000, dioxane 1000, dichloromethane 850, benzene 770, trichloroethylene 720, xylene 600; Stability:pp'-DDT undergoes dehydrochlorination in alkaline solutions and at temperatures above the melting point to the non-insecticidal 1,1'-(2,2-dichloroethenylidene)-bis(4-chlorobenzene) (DDE). This reaction is catalysed by ferric chloride, aluminium c. DDT is extremely nonvolatile. Crystallization point min. 90°C; acidity (as sulfuric acid) max. 0.3% in weight; water: max. 1% in weight. DDT is unstable in the presence of alkalies and is incompatible with alkaloid nicotine and dolomite. Bordeaux mixture, ferbam, and some clays may cause a slight decomposition. Soluble in apolar organic solvents. Limited solubility in aliphatic oils.

Oral:Acute oral LD₅₀ for rats 113-118 mg/kg, mice 150-300 mg/kg, rabbits 300 mg/kg, dogs 500-750 mg/kg, sheep and goats >1000 mg/kg. Percutaneous:Acute percutaneous LD₅₀ for female rats 2510 mg/kg. Inhalation:Relatively non-toxic. Phytotoxicity:Phytotoxic to cucurbits, beans, young tomato plants, and some varieties of barley. ADI:0.13 mg/kg.

Ecotoxicology: 
Bees: LD₅₀ (oral) 5 µg/bee.Birds:Moderately toxic.Daphnia:LC ₅₀ (48 h) 1.10 µg/l.Fish:Toxic to fish and aquatic life; 50 (96 h) for Coho salmon 4, rainbow trout 7, yellow perch 9 ppb.Other aquatic spp.: LC₅₀ for Crangon septemspinosa (shrimp) 0.4 µg/l. Environmental fate: 
EHC 83 reviews resistance to degradation, widespread persistence in the environment, and high potential for bioaccumulation; this review concludes that DDT and its metabolites should be regarded as a major hazard to the environment. Animals:In rats, following oral administration, DDT is metabolised to 1,1'-(2,2-dichloroethenylidene)-bis(4-chlorobenzene) (DDE), 1,1'-(2,2-dichloroethylidene)-bis(4-chlorobenzene) (DDD), 1,1'-(2-chloroethenylidene)-bis(4-chlorobenzene), 1,1'-(2-chloroethylidene)Soil: DT₅₀ in India (tropical) c. 3 mo; in temperate regions, DT₅₀ is 4-30 y.
WATER SOLUBILITY: 0.0055 ppm.

Signal Word:CAUTION; Hazard Class:II (Moderately hazardous)