Methacrolein

Methacrolein, or methacrylaldehyde, is an unsaturated aldehyde. It is a clear, colorless, flammable liquid.

Methacrolein is one of two major products resulting from the reaction of isoprene with OH in the atmosphere, the other product being Methyl vinyl ketone (MVK, also known as butenone). These compounds are important components of the atmospheric oxidation chemistry of biogenic chemicals, which can result in the formation of ozone and/or particulates.