What does DDT mean chemically


DDT, Abbreviation for D.ichlordiphenyltrichloroethane, a colorless, crystalline substance belonging to the group of chlorinated hydrocarbon insecticides with contact insecticidal properties; M.p. 108.5 ° C, b.p. 185 to 187 ° C at 7 Pa. DDT is easily soluble in cyclohexanone, dioxane, trichloroethane, benzene, xylene, acetone, soluble in chloroform, ether, slightly soluble in ethanol, methanol, ≈ 0.001 mg / l in water.

DDT is largely stable to light, air and acid. Under alkaline conditions, however, the biologically inactive one easily forms through HCl elimination D.ichlordiphenyldichlorethen (DDE). This reaction is catalyzed by iron and aluminum compounds. The synthesis of DDT takes place through the condensation of chloral with chlorobenzene under the influence of sulfuric acid or oleum:

The technical product is a solid yellowish mass with a softening point of approx. 90 ° C. It contains about 70% p,p'-DDT and, as the most important by-product, about 20% of the insecticide is only weakly effective O,p'-DDT.

For many insect species, DDT has a very strong contact poison and pest toxin effect. Diptera (flies and mosquitoes) and biting insects (caterpillars, beetles) are very sensitive, aphids less, and spider mites not at all. The substance is highly lipophilic. It promotes easy penetration of the insect cuticle and thus the contact poison effect. It acts as a neurotoxin. The acute toxicity to warm blooded animals is relatively low: p.o. LD50 = 250 to 500 mg / kg rat.

The accumulation of DDT and its main metabolite DDE in adipose tissue is problematic. As the final stage of metabolism, the warm-blooded animal uses the hydrophilic dichlorodiphenylacetic acid (DDA) excreted in the urine. The lethal oral dose for the adult human is estimated to be 20 to 30 g. There are no known cases of chronic poisoning. MAK 1 mg / m3.