The different types of antifreeze include ethylene glycol and propylene glycol, which are prominently used as car engine coolants. Less popular antifreeze agents are methanol and 1, 3 propandiol and glycerol.
Antifreeze retains its liquid form when heated to a point where other liquids boil. As such, it serves as an excellent coolant, because liquids transfer heat away from a solid much better than gases do. Methanol is flammable, and therefore unpopular for use as antifreeze in cars. Ethylene glycol can be used in cars, but is less popular than propylene glycol because of its toxicity to animals. Propylene glycol is much less toxic than the others, although it is subject to biological contamination.