Is it possible to boil a water and ethylene glycol mixture and distill the vapor to get pure water or will the ethylene glycol evaporate with the water? How about organic coolants like GM’s Dexcool?
I want to know for survival when the apocalypse comes. There are millions of radiators out there with a lot of water.
Well, wikipedia says ethylene glycol boils at 387 °F so you’d need a hell of a fire to get it boiling. The water would boil out before the glycol would. As for the other ingredients in radiator fluid, I have no idea their boiling points. Best way to do it is I’d recommend freezing the whole thing first, (the glycol will stay liquid down to 9º F) then boiling the resultant ice to get rid of the rest.
a 50% antifreeze mixture prevents freezing to about -34F, a 60% antifreeze mixture prevents freezing to about -62F. it would be a difficult separation for finding temperatures to fractionally freeze it.
you could do like dumb animals and eat snow where available in below freezing temperatures and find puddles/ponds/lakes/streams/rivers in above freezing temperatures.
Which is exactly how distillation works… just collect the water vapor and condense it out. The ethylene glycol remains a liquid and won’t even get close to boiling until well after the water has boiled off.
Very thin margin of error there. It doesn’t take much ethylene glycol to be fatal.
Actually that’s not true either. Oral LD50 is 4700 mg/kg (that’s the dose that will kill a lab rat half the time). For humans, LDLO (the lowest known lethal dose) is 786 mg/kg. An average adult (weight 80 kg) would have to consume 62 grams of pure ethylene glycol to reach the the lowest known lethal dose. That’s a quarter cup of straight antifreeze, or a half cup of engine coolant.
I’m pretty confident that you could distill water out from the engine coolant if you did it right. Trace amounts of ethylene glycol aren’t (acutely) toxic. At least, I’d drink the distilled coolant before hazarding a lake that’s contaminated with Guaranteed Zombie Virus.
The EPA’s estimated reference dose of ethylene glycol, below which there are no known toxic effects, is 2 mg/kg/day, and that’s probably a conservative estimate. My WAG is that it would be pretty easy to get a distillate with less than a tenth of a percent of ethylene glycol, at which point you can drink all you want.
Are there other toxic compounds in engine coolant?
The ethylene glycol won’t boil but it will still have a non-zero vapor pressure and be present in the gas phase. Based on the vapor-liquid equilibrium data, boiling a ~50/50 mix of ethylene glycol and water will result in a vapor that is about 3% glycol.
I don’t think I would feel comfortable drinking that condensate, but you could distill it again and should be in pretty good shape at that point.
I would empty the radiator into a pot/pan, and start a fire underneath to bring the water to a boil. Then I would take a piece of plastic sheeting or thin metal that could be manipulated (aluminum foil, gutter, etc) and hang it over the boiling water at a slight sloping angle toward a bucket or jug that would collect the water. As the steam rises, it will condense on the plastic, and eventually drip in to your container.
I would feel comfortable drinking as-is if I were in a pinch, but I would really want to pour it through a 5 gallon bucket packed with layered charcoal and sand. At the bottom of the bucket I would cut a hole, and collect the water as it drained out. Better than Mama used to make.