I am aware that a 50% solution of propylene glycol in water has a boiling point of 188 Celsius. Aside from other glycols and oil baths, what other
benign solutes would you recommend for even heating from 150 - 200 centigrade? I’m looking at both steam bath or perhaps immersion bath heating.Deathunter88 - 7-9-2024 at 13:04
[Edited on 7-9-2024 by Deathunter88]chloric1 - 7-9-2024 at 16:02
Thanks interesting link. But I was looking for something more inert and under 200 Celsius. Using molten oxidizing salts to heat up corrosive or
oxidizing or reducing for that matter, reagents would be a feat to behold! Pray the glassware doesn’t fail! Definitely don’t spill that salt on wood or paper either!
Seriously though I’d just use a sand bath when distilling acids!
[Edited on 9/8/2024 by chloric1]
[Edited on 9/8/2024 by chloric1]
Obvious question
Sulaiman - 7-9-2024 at 23:15
Why not use a heating mantle?chloric1 - 10-9-2024 at 13:40
Well that would certainly be easier wouldn’t it? I plan on getting one but it’s not yet in my budget and I have a few more other things to get
first. For now, I’ll be using 1000 ml crystallizing dishes for water/sand baths as my round bottom flask is 500 mlclearly_not_atara - 10-9-2024 at 15:12
I'm not sure about this but I think that MgCl2/H2O will produce "relatively" stable liquids up to 200 C. In general if the vapor pressure is less than
0.25 atmospheres then the evaporation rate should be pretty low.
The attached paper discusses the vapor pressures of solutions of MgCl2 and KCl, with the former probably being a little cheaper. The results are
expressed as equations which I don't feel like analyzing but it seems clear that MgCl2, which is both strongly hygroscopic and relatively stable below
300 C, does a good job of substantially reducing the vapor pressure of aqueous solutions, allowing you to use MgCl2 brines as salt-water baths well
above 100 C.
MgCl2 solution is obviously obtained OTC from MgSO4 + CaCl2 metathesis but the result is hard to filter. However this may be worth it in this case.
This is a topic I've considered many times before and I'm sort of glad that you brought it up so that I would finally look into it seriously.
EDIT: forgot to attach the paper lol
[Edited on 10-9-2024 by clearly_not_atara]
Attachment: shibue2004.pdf (228kB) This file has been downloaded 48 times
chloric1 - 10-9-2024 at 17:34
Yo this awesome! Plus the magnesium chloride is nonflammable and non oxidative! This is the kind of solution I was looking for. I might be able to
get magnesium chloride without double displacement relatively inexpensively. I’ll have to look into it. But I might do the double displacement
because I have 4 pounds of Epsom salts. I’m drying my ammonium nitrate made from calcium nitrate and ammonium sulfate. I have come away from that
synth with the realization that concentrated solutions are more headache and not worth extra work. Going forward I will use moderate to dilute
concentration. I may even prolong boiling the precipitate to “mature” it.DraconicAcid - 10-9-2024 at 19:52
Water baths, yes, but definitely not steam baths.clearly_not_atara - 11-9-2024 at 10:46
So it appears that you can get to around 150 C, although you may need to keep replenishing the water.
Definitely don’t spill that salt on wood or paper either! 
