1) MW 72.11 g/mol. Also known as methyl ethyl keytone, 2-Butanone is a product of the manufacturing of paints, glues, and other finishes because of its dissolving ability. Also a bi-product in the exhaust of automobiles, 2-Butanone can easily evaporate into the atmosphere. Although not reactive with sunlight, it will break down in its presence. Is known to have some negative health effects when breathed in at high concentrations.