1,3-Butanediol, also known as Ketohol when used as an alcohol substitute, is an organic compound with the formula CH3CH(OH)CH2CH2OH, not to be confused with 1,4-butanediol. With two alcohol functional groups, the molecule is classified as a diol. The compound without the R (or D) designation is racemic, which is what has been used in most studies before 2023. The compound is a colorless, bittersweet, water-soluble liquid. It is one of four common structural isomers of butanediol. It is used in grape flavoring, and as a precursor to some antibiotics.

Production and uses

Hydrogenation of 3-hydroxybutanal gives 1,3-butanediol:

CH3CH(OH)CH2CHO + H2 → CH3CH(OH)CH2CH2OH

Dehydration of 1,3-butanediol gives 1,3-butadiene:

CH3CH(OH)CH2CH2OH → CH2=CH-CH=CH2 + 2H2O

1,3-Butanediol is marketed commercially as an alcohol substitute under the brand name Ketohol.

Pharmacology

1,3-Butanediol has sedative, hypotensive and hypoglycaemic action comparable to ethanol, with the (R), also known as (D), enantiomer being more active. Fatty acid esters of 1,3-butanediol such as the acetoacetate, lactate or hexanoate have been studied for inducing ketogenesis.

Occurrence

1,3-Butanediol has been detected in bell peppers (Capsicum annuum). 1,3 Butanediol maintains FDA GRAS status as a flavor molecule.