Chemistry · Ch 14 — Haloalkanes and Haloarenes
DDT
DDT
DDT (p,p'-dichlorodiphenyltrichloroethane) was first prepared in 1873; Paul Muller discovered its effectiveness as an insecticide in 1939 and was awarded the 1948 Nobel Prize in Medicine and Physiology for the discovery. Preparation: heating a mixture of chlorobenzene with chloral (trichloroacetaldehyde) in the presence of concentrated H2SO4 gives DDT + H2O (two chlorobenzene rings condense onto the chloral carbon). Uses: (i) controls insects that carry diseases such as malaria and yellow fever; (ii) controls agricultural pests on farms; (iii) used in building construction for pest cont …
Worked out. Book's practice box (no printed solution): what is the IUPAC name of DDT, and why is its use banned in most countries? IUPAC name: 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane. It is banned because it is chemically very stable and barely biodegradable, so it persists in soil and water for years, bioaccumulates up the food chain in fatty tissue, and -- famously -- thins the eggshells of birds of prey, crashing their populations, besides posing long-term toxicity risks to other wildlife and to human health (own solution, not printed in th …