Acrolein

Acrolein, also known as propenal or 2-propenal, is the simplest member of the α,β-unsaturated aldehydes. Its structure features a conjugated H2C=CH–CHO system, making it highly reactive as both an aldehyde and an electrophile. It is a colorless, highly volatile liquid with a sharp, acrid odor and a tendency to polymerize if not stabilized.

Production and occurrence: Acrolein is produced industrially by the catalytic oxidation of propylene, typically over vanadium oxide catalysts, with concurrent formation of acrylic acid in some processes. It also appears as a byproduct in the oxidation of glycerol, a component of biodiesel production. In the environment, acrolein can be generated during combustion processes, including tobacco smoke and the burning of fats or oils.

Applications and reactivity: As a versatile chemical intermediate, acrolein is used in the manufacture of acrylic esters, acrylic acid, and related polymers. It participates in a wide range of reactions, including conjugate additions and aldol-type processes, and can polymerize rapidly, especially in the presence of radicals or bases. Storage and handling require stabilizers or inhibitors to prevent unwanted polymerization.

Safety and regulation: Acrolein is a potent irritant to the eyes, skin, and respiratory tract and is toxic by inhalation. Due to its reactivity and hazards, it is subject to strict handling, ventilation, and exposure controls in workplaces, and regulatory limits are imposed in many jurisdictions.

Environmental impact: It is a volatile organic compound that can contribute to air pollution and is removed or transformed in the atmosphere mainly by reactions with oxidants such as hydroxyl radicals.