Molecule of the Week
January 20, 2014
4-Methylcyclohexanemethanol (MCHM) is an alicyclic alcohol that commonly exists as a mixture of trans (shown) and cis isomers. It is a colorless liquid that smells like mint or licorice. It is toxic to animals and humans, if it is breathed, swallowed, or allowed to come into contact with skin.
MCHM was first prepared by reducing the corresponding diester. It is currently obtained as a byproduct of 1,4-cyclohexanedimethanol, which is made by hydrogenating dimethyl terephthalate.
MCHM’s primary use is in the process for “washing” coal (removing impurities such as sulfur, rock, and soil by flotation). On January 9, 2014, MCHM was discovered to be leaking from a storage tank into West Virginia’s Elk River. Several thousand gallons of the compound contaminated water supplies in nine counties, and residents were warned not to use tap water for any purpose.