Description
DDT is a banned organochlorine insecticide. It has a low aqueous solubility, is relatively volatile and has a low potential to leach to groundwater. It is highly persistent in soil and non-mobile. It is moderately toxic by the oral route in humans and other mammals but is a carcinogen and endocrine disrupter. It shows a high to moderate level of toxicity to most animals and insects although it is relatively non-toxic to birds.
Uses
1,1,1-Trichloro-2,2-bis(o-chlorophenyl)ethane is a byproduct in the synthesis of 2,4''-Dichlorodiphenyltrichloroethane (D434205). 2,4''-Dichlorodiphenyltrichloroethane is a chlorinated organic pesticide having estrogenic activity.
Production Methods
O,O′-DDT was not manufactured through a dedicated, separate synthetic route; instead, it arose as a minor isomeric by-product of the same industrial process used to make P,P′-DDT. Commercial producers condensed chloral (trichloroacetaldehyde) with unrefined or mixed-isomer chlorobenzenes under strongly acidic conditions (typically concentrated sulphuric acid or oleum). When O-chlorobenzene reacted with chloral twice, rather than the para isomer, the process yielded O,O′-DDT, a fully ortho-substituted isomer. Because the reaction strongly favours para substitution, O,O′-DDT formed only in trace amounts, appearing in the crude DDT mixture that was later neutralised, washed, and crystallised. It was never produced as an intentional commercial product, only as an unavoidable by product of early DDT manufacture.
