The Role of Chemistry in History

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DDT molecule

April 22nd, 2008 · No Comments ·

Introduction / DDT molecule / Malaria / World War II

Environmental Problems / Insect Resistance / Begin Using Again?  /  References

DichloroDiphenylTrichloroethane or DDT is comprised of:

  • A chloral hydrate molecule [CCl3CH(OH)2] as the center “stem”
    • this molecule has sleep producing properties and is known as “knockout drops” in night clubs.


  • The two ends of the molecule are Monochlorobenzene (C6H5Cl)
    • basically a benzene ring with a chlorine atom interchanged with a hydrogen

  • The monochlorobenzene attaches to the OH group of the chloral hydrate molecule and water is released.


  • It is a unique insecticide in that it kills both types of insects
    • 2 types:
      • 1. insects that chew plants
        • these insects are killed with the stomach poison aspect of DDT when they ingest the plant.
      • 2. insects that puncture plants and suck out juice
        • these insects are killed as soon as they come in contact with the plant.
  • It also has a “residual effect” so the effects last for a long time without the need for the area to be resprayed. It can be effective 6 months or more.
  • DDT is not water soluable so it needed to either be dissolved in kerosene, made into an emulsion, or the grains were chemically coated to make a wettable powder.
  • Because of its insolubility it is not metabolized quickly in animals. The half life is 8 years, so it takes an animal 8 years to digest half of its total intake of the molecule.


Tags: DDT