CCl3CHO

CCl3CHO, also known as 2,2,2-trichloroacetaldehyde or chloral, is an organochlorine aldehyde with the formula C2HCl3O. It consists of a formyl group (CHO) attached to a trichloromethyl substituent (CCl3). The compound is a colorless, reactive liquid at room temperature.

The aldehyde carbonyl is strongly electrophilic due to the electron-withdrawing CCl3 group, making chloral highly reactive toward nucleophiles. It readily forms a gem-diol by hydration with water to give chloral hydrate (CCl3-CH(OH)2).

Chloral is typically prepared by chlorination of acetaldehyde under controlled conditions, in which the three hydrogens of the methyl group are replaced by chlorine. This production requires careful handling due to the compound's reactivity and toxicity.

In aqueous media, chloral exists in equilibrium with chloral hydrate. It can react with alcohols to form hemiacetals or acetals, and it serves as a reactive aldehyde in various organic synthesis applications.

Chloral is used as the precursor to chloral hydrate, a sedative and hypnotic that was widely employed in the 19th and early 20th centuries. Its medical use has diminished due to safety concerns and the availability of safer alternatives. It remains of interest in synthesis and research as a reactive aldehyde.

Safety considerations for chloral are significant. It is toxic and potentially harmful if inhaled, ingested, or absorbed through the skin. It is an irritant and can contribute to central nervous system depression. Because of its potential for abuse and production hazards, it is subject to regulatory controls in many countries.