I think water is rather rare as a coolant these days. Organics (chemical sense not farming sense) like propylene glycol or some kind of glyme aren’t potentially corrosive to metals if spilled, are harder to grow shit in, have lower volatility, and have a higher thermal limit. Maybe also with a little bit of antifouling agent thrown in. My main gripe with them is that if you do spill them, they don’t evaporate and you’re slipping over the floor for the next few days because you missed a spot.
For legal reasosns, the following is a dramatization of events.
I feel this in my goddamn BONES because the thing vents at 135 FREAKING DECIBELS and I’m TRAPPED 2 METERS from it trying to measure out 0.0000023 mg of a temperature-sensitive metal complex in the glove box that I spent the last 2 weeks trying to make and POUND SAND EHS WITH YOUR PENCIL-PUSHING SCOPE-CREPT DEPARTMENT POLICIES I WILL WEAR HEARING PROTECTION WHERE I DAMN WELL PLEASE! WHAT’S THAT? I WON’T HEAR IF SOMETHING “GOES WRONG”? IS THAT SO? GEE, I HADN’T CONSIDERED THAT! LET ME CHECK IF REGULAR EXPOSURE TO THE LABORED MUSINGS OF SATAN’S FROSTY ANUS COULD POSSIBLY AFFECT MY ABILITY TO HEAR THINGS “GOING WRONG”!
While I’m at it, A CERTAIN LIQUID AIR COMPANY OUGHT TO FEEL ASHAMED FOR NOT DITCHING THEIR JANKY OLD DEFECTIVE DEWARS, DON’T YOU DARE TRY TO BLAME IT ON ME LEAVING THE PRESSURE BUILDER ON, FIRST THING I CHECK
¯_(ツ)_/¯ I was just trying to highlight a fun fact about how they act similarly metabolically.
But since you asked, according to wikipedia, the oral LD50s for acetone and isopropanol (taking average of values for rats, mice, and rabbits) are 4713 and 3655 mg/kg, respectively. Extrapolating to a 75 kg human, that’s 451 and 349 mL for a 50/50 shot at permanent night-night. For comparison, ethanol is ~7300 mg/kg -> 694 mL by the same metric.
I don’t think your comment emphasizes enough how like drinking rubbing alcohol drinking acetone would be. Rubbing alcohol (isopropanol) is, in fact, metabolized directly to acetone when ingested. The acetone can be metabolized further, but a good chunk is also simply exhaled.