Antifreeze

Antifreeze, chemical substance added to a liquid to lower its freezing point. It prevents the freezing of the coolants used in airplane, automobile, and tractor engines, in refrigeration liquids, and in snow-melting and deicing agents.

The ideal antifreeze should be chemically stable, be miscible in the coolant, have low viscosity and electrical conductivity and a high boiling point, be noncorrosive, and have good heat-transfer properties. The most widely used antifreeze materials in automotive engines today are methyl alcohol, ethyl alcohol, and ethylene glycol; most of them contain a phosphate, nitrate, or other anticorrosive agent.