1,4-Butanediol, also called Butane-1,4-diol, is a primary alcohol and an organic compound with the formula HOCH2CH2CH2CH2OH. It is a colorless viscous liquid. It is one of four stable isomers of butanediol.

1,4-Butanediol is similar to but distinct from 1,3-Butanediol.

Synthesis
In industrial chemical synthesis, acetylene reacts with two equivalents of formaldehyde to form butyne-1,4-diol. Hydrogenation of butyne-1,4-diol gives butane-1,4-diol.[5] It is also made on an industrial scale from maleic anhydride in the Davy process, which is first converted to the methyl maleate ester, then hydrogenated. Other routes are from butadiene, allyl acetate and succinic acid.

A biological route to BD has been commercialized that uses a genetically modified organism.[6] The biosynthesis proceeds via 4-hydroxybutyrate.