Wikipedia on antifreeze:
"When ethylene glycol is used in a system, it may become oxidized to five organic acids (formic, oxalic, glycolic, glyoxalic and acetic acid). Inhibited ethylene glycol antifreeze mixes are available, with additives that buffer the pH and reserve alkalinity of the solution to prevent oxidation of ethylene glycol and formation of these acids. Nitrites, silicates, theodin, borates and azoles may also be used to prevent corrosive attack on metal"
...
"Propylene glycol is considerably less toxic than ethylene glycol and may be labeled as "non-toxic antifreeze". It is used as antifreeze where ethylene glycol would be inappropriate, such as in food-processing systems or in water pipes in homes where incidental ingestion may be possible. For example, the
FDA allows
propylene glycol to be added to a large number of
processed foods, including
ice cream,
frozen custard, salad dressings, and
baked goods, and it is commonly used as the main ingredient in the "
e-liquid" used in
electronic cigarettes.
Propylene glycol
oxidizes when exposed to air and heat, forming
lactic acid.
[9][10] If not properly
inhibited, this fluid can be very corrosive,[
citation needed] so
pH buffering agents such as
dipotassium phosphate and
potassium bicarbonate are often added to propylene glycol, to prevent acidic corrosion of metal components."
Antifreeze in ice cream. Yum.
