Butanediol
Butanediol, also called butylene glycol, may refer to any one of four stable structural isomers: 1,2-Butanediol 1,3-Butanediol 1,4-Butanediol 2,3-Butanediol == Geminal diols == There are also two geminal diols (gem-diols), which are less stable: 1,1-Butanediol, hydrate of butanal 2,2-Butanediol, hydrate of butanone == Isobutylene glycol and methylpropanediol == Isobutylene glycol may be considered a kind of butylene glycol, similarly to butane historically including n-butane and i-butane (isobutane). The modern name for the closely related type of compounds is methylpropanediol.