butanediol

:  any of four isomeric glycols C₄H₈(OH)₂: such as a :  a hygroscopic liquid CH₃CHOHCH₂CH₂OH made usually by hydrogenation of aldol and used chiefly as a humectant and plasticizer —called also 1,3-butanediol, 1,3-butylene glycol b :  a viscous liquid CH₂OHCH₂CH₂CH₂OH made from acetylene, formaldehyde, and hydrogen and used chiefly in making polyurethane resins —called also 1,4-butanediol, 1,4-butylene glycol, tetramethylene glycol c :  a hygroscopic viscous liquid or crystalline solid CH₃CHOHCHOHCH₃ known in four optically different forms, obtained usually by fermentation (as of grains or molasses), and used chiefly in organic synthesis —called also 2,3-butanediol, 2,3-butylene glycol