paraldehyde

Paraldehyde is a cyclic trimer of acetaldehyde, with the chemical formula (C2H4O)3. It is a colorless liquid with a distinct, pungent odor that is often described as ethereal or fruity. It is typically synthesized by the trimerization of acetaldehyde, a reaction catalyzed by acids. Paraldehyde is soluble in water and many organic solvents.

Historically, paraldehyde was widely used as a sedative and hypnotic medication. It was administered orally, rectally, or intramuscularly to induce sleep and to treat anxiety and delirium tremens, a severe withdrawal symptom of alcoholism. Its use as a pharmaceutical has significantly declined due to its narrow therapeutic index, potential for dependence, and the availability of safer and more effective alternatives. It can cause respiratory depression and has a relatively low margin of safety.

In some industrial applications, paraldehyde is used as a solvent or as a chemical intermediate in the synthesis of other compounds. Its chemical properties allow it to participate in various reactions. Due to its potential for misuse and its historical association with sedative effects, its handling and distribution are often subject to regulatory controls in many regions.