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.
It is present in cigarette smoke.
Industrially, the primary use of methacrolein is in the manufacture of polymers and synthetic resins.
Exposure to methacrolein is highly irritating to the eyes, nose, throat and lungs.
The essential oil of the plant Big Sagebrush (Artemisia tridentata) contains 5% methacrolein.
See also
References
Crotonaldehyde
Crotonaldehyde is a chemical compound with the formula CH3CH=CHCHO. The compound is usually sold as a mixture of the E- and Z-isomers, which differ with respect to the relative position of the methyl and formyl groups. The E-isomer is more common (data given in Table is for the E-isomer). This lachrymatory liquid is moderately soluble in water and miscible in organic solvents. As an unsaturated aldehyde, crotonaldehyde is a versatile intermediate in organic synthesis. It occurs in a variety of foodstuffs, e.g. soybean oils.
Production and uses
Crotonaldehyde is produced by the aldol condensation of acetaldehyde:
Its main application is as a precursor to fine chemicals. Sorbic acid, a food preservative, and trimethylhydroquinone, a precursor to the vitamin E, are prepared from crotonaldehyde. Other derivatives include crotonic acid and 3-methoxybutanol.
Crotonaldehyde is a multifunctional molecule that exhibits diverse reactivity. It is an excellent prochiral dienophile. It is a Michael acceptor. Addition of methylmagnesium chloride affords 3-penten-2-ol.
Podcasts:
