[nlieb]

First off, I would just like to say that this has nothing whatsoever to do with overclocking. I'm doing a legitimate experiment involving a form of electrolysis of water that in theory should only become feasible at low temperatures. I was hoping to use dry ice as a coolant, because it is cheap and readily available.

First: what antifreezes have eutectic points at or below dry ice's sublimation temperature?

Second: which of these will not decompose when a low-voltage current is passed through a mixture of it with water (conductivity in this case is irrelevant - suffice to say I don't need an electrolyte)?

Third: Which of those meeting conditions one and two has the lowest molarity at its eutectic point?

Thanks all...

[Enthalpy]

I have absolutely nothing whatsoever against overclocking. Is it supposed to be a kind of offense, insult, sin...?

Dry ice sublimates at −78.5 °C. That's too cold for eutectics with table salt (which in addition decomposes during electrolysis), glycerine (-38°C), propylene glycol (-60°C), ethylene glycol (Wiki gives -45°C but Huntsman and Dow Chemical stop measuring at --50°C, looks like -60°C), di- and tri-ethylene glycol (less good than mono-).

Found ethanol at -120°C; -80°C would need 84% ethanol
http://en.wikipedia.org/wiki/File:Phase_diagram_ethanol_water_s_l_en.svg

And methanol, of which 70% achieve -82°C, the eutectic colder
http://www.engineeringtoolbox.com/methanol-water-d_987.html

You may have chances with some acid as well. Highly concentrated, it prevents freezing and makes a good electrolyte. 38% sulphuric gives -73°C, so just check others.

I expect the alcohols to dissociate faintly and electrolyze little; anyway, they should recombine with water, so that only oxygen evolves. Then, you need something to ionize water but doesn't react with an alcohol. An alkali?

Please be careful with the alcohols, as they're all toxic. Ethanol is toxic, carcinogenic, mutagenic, teratogenic - the whole spectrum - methanol is worse, glycol is knowingly unsound. Many burn and are uneasy to extinguish.

[billnotgatez]

Ethanol is toxic, carcinogenic, mutagenic, teratogenic

That is amusing

so is this
http://www.dhmo.org/facts.html

@Enthalpy
I apologize if you found the above mean or highhanded
I could not resist considering how much ethanol we consume

[Enthalpy]

Fun.

I don't expect an experienced chemist to run into trouble with ethanol. But other people thinking "just alcohol", possibly.

The other way round: as I began reading Msds, finding the one for ethanol did relativize the dangers meant in the doc.