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substance added to a solvent to lower its freezing point. The solution formed is called an antifreeze mixture. Antifreeze is typically added to water in the cooling system of an internal-combustion engine so that it may be cooled below the freezing point of pure water (32°F; or 0°C;) without freezing. Any substance that dissolves will cause freezing-point depression (see colligative propertiescolligative properties,
properties of a solution that depend on the number of solute particles present but not on the chemical properties of the solute. Colligative properties of a solution include freezing point (see freezing), boiling point, osmotic pressure (see osmosis), and
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); a desirable antifreeze also should not corrode metal parts, attack rubber, become viscous at low temperatures, or evaporate readily at the ordinary engine operating temperature. It should be chemically stable, a good conductor of heat, and a poor conductor of electricity. Ethylene glycolglycol
, dihydric alcohol in which the two hydroxyl groups are bonded to different carbon atoms; the general formula for a glycol is (CH2)n(OH)2.
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 is the most widely used automotive cooling-system antifreeze, although methanol, ethanol, isopropyl alcohol, and propylene glycol are also used. Substances that inhibit corrosion are usually added; antifoaming agents are sometimes added as well. In automotive windshield-washer fluids, an alcohol (e.g., methanol) is usually added to keep the mixture from freezing; it also acts as a solvent to help clean the glass. The brine used in some commercial refrigeration systems is an antifreeze mixture; it is typically a water solution of calcium chloride or propylene glycol.



a liquid with a low freezing point, used for cooling internal combustion engines and other equipment operating at temperatures below 0°C. The primary requirements for antifreeze are high heat capacity, thermal conductivity, boiling point, and flash point; low viscosity at low temperatures, small vapor pressure, and as little foaming as possible. In addition, antifreeze must not be very corrosive to the metals from which the cooling system parts are made and must not eat away hose and gasket materials. These requirements are met to a greater or lesser degree by aqueous solutions of ethylene glycol, glycerine, certain alcohols, and other organic compounds as well as by aqueous salt solutions (for instance, calcium chloride).

The best antifreeze materials are aqueous solutions of ethylene glycol with anticorrosion additives to prevent corrosion (such as sodium phosphate). It is possible to obtain mixtures with a freezing point as low as -75°C (66.7 percent ethylene glycol and 33.3 percent water). Upon freezing, such solutions increase in volume insignificantly (0.3 percent with a 55 to 65 percent water content) and when cooled below freezing do not rupture pipes and radiators of the cooling system.

Domestic industry manufactures brands 40 and 65 ethylene glycol antifreeze (freezing points of -40°C and -65°C, respectively) with sodium phosphate and brand 40 M with sodium molybdate.


Motornye i reaktivnye masía i zhidkosti. Edited by K. K. Papok and E. G. Semenido, 4th ed. Moscow, [1964].
Bobrov, N. N., and P. I. Voropai. Primenenie topliv i smazochnykh materialov, 2nd ed. Moscow, 1968.



A substance added to a liquid to lower its freezing point; the principal automotive antifreeze component is ethylene glycol.


a liquid, usually ethylene glycol (ethanediol), added to cooling water to lower its freezing point, esp for use in an internal-combustion engine
References in periodicals archive ?
Paul, who lives with wife Jodie, 37, daughter Aoife, nine, and son Cillian, six, said pets are attracted to anti-freeze as it tastes sweet.
In addition to the demands made on "Prestone" anti-freeze, thousands of tons of raw materials necessary for its manufacture are now being used in making vital defense equipment of many different kinds.
Watched The Supervet on TV treat a cat with anti-freeze poisoning.
Sian Griffiths' cat Belle died after being poisoned by anti-freeze at the end of October 2015
The sweet taste of ethylene glycol, present in many anti-freeze brands, attracts cats.
Figures from The Veterinary Poisons Information Service, which offers vets specialist advice about poisoned pets, reveal that the most common cause of death in more than 200,000 pets is down to ethylene glycol poisoning - the deadly ingredient in anti-freeze.
Penny Lott, clinic director at White Cross in Gateacre said: "Ethylene glycol in anti-freeze is naturally sweet tasting, which appeals to cats and dogs, as well as other pets and wildlife, but even tiny amounts are highly toxic and can quickly lead to kidney failure and death.
But in the meantime we would ask everyone in the area to check where they keep their anti-freeze and make sure it is secure and out of the way of cats.
It is understood the cat called Fudge was suffering from anti-freeze poisoning symptoms and he had to be put to sleep as nothing further could be done to save him.
And although they say a little anti-freeze isn't going to hurt you, obviously given a choice you don't want to be eating anti-freeze," he added.
The first of the new oils is Globaltherm" PG, containing proypylene glycol, and intended for use in the lbod industry as an anti-freeze in thermal fluid systems and is regarded as safe by the US FDA for use as a direct and indirect food additive.
A SPATE of cat deaths due to anti-freeze poisoning has seen the RSPCA issue a warning.