English

Etymology

Contracted from chlor(ine) and al(cohol)

Noun

1. A colourless narcotic liquid, trichloro-acetaldehyde, CCl3CHO, obtained at first by the action of chlorine on alcohol and that, when treated with water, produces chloral hydrate.

Translations

• Italian: cloralio

Related terms

• chloralamide

Chloral, also known as trichloroacetaldehyde or trichloroethanal is an organic halide discovered in 1832 by Justus von Liebig. In its pure form, it is a colourless oily liquid soluble in alcohol and ether. In water it reacts to form chloral hydrate, a sedative/hypnotic substance notorious for its use in "knockout drops" such as the Mickey Finn.

Chloral is produced by chlorination of ethanol:

4 Cl2 + C2H5OH → Cl3CCHO + 5 HCl

or if water ethanol mixtures are used the hydrate is formed first and de hydrated with sulfuric acid:

4 Cl2 + C2H5OH + H2O → Cl3CCH(OH)2 + 5 HCl

1 Cl3CCH(OH)2 → Cl3CCHO + H2O

Chloral reacts with chlorobenzene to form DDT (with sulfuric acid as a catalyst). This was the reaction which was discovered by Othmar Zeidler in 1874 and used to produce DDT in industry.

References