Sciencemadness Discussion Board

ethylene glycol

Polverone - 10-2-2004 at 22:34

I would like some of this compound to experiment with. Ideally, as with all chemicals, it should be inexpensive, readily obtained, and pure. But I'll take what I can get.

Is antifreeze truly the best/only OTC way (assuming that I don't want to start from ethylene)? I've seen some indication that there may be brake fluids that contain it, but the few MSDS I have looked at indicated complex mixtures.

BromicAcid - 11-2-2004 at 01:13

Well if you did want to start from ethanol and go to ethylene you could react ethyl alcohol with a paste of concentrated H2SO4 with sand at high heat to yeild ethene. Then bubble the gas though a basic solution of potassium permanganate to get your ethylene glycol.

HOCH2CH3 --H2SO4--> CH2CH2 + H2O

But if you just want to get your ethylene glycol from OTC sources I really can't help you there, I know nothing about purities or brands or anything.

[Edited on 2/11/2004 by BromicAcid]

ethylene glycol

leopard - 11-2-2004 at 16:32

Polverone I did an MSDS search of several brands of anti-freeze a while back and found that the more expensive "Brand Name" ones (eg. PRESTONE) were about 90% pure with the remainder comprised of water, anti-rusting agents, anti-gelling agents etc. The lesser known low cost brands (eg. PEAK brand) were 95% pure with less of the additives. I found the PEAK brand worked fine for EDN.

Haggis - 11-2-2004 at 16:51

I remember reading a while back on the E&W that NBK had aquired EG in relatively pure amounts with only a slight methanol contamination in the form of antifreeze. The thread discussed nitrogen mustards, IIRC.

One could easily distill over the methanol for relatively pure EG. What are you going to use it for? Is it something in which a dye wouldn't matter, or is it something a bit more sensitive?

chemoleo - 11-2-2004 at 16:52

How about using any antifreeze, evaporating any water off with heat (ethylene glycol has a boiling point of 198 deg C - so you will get rid off most other volatiles before that), and THEN adding H2SO4/H3PO4 to form dioxane (reflux)?
Dioxane distills off at 101.5 deg C. This way you should get rid off 1) all low boiling volatiles and 2) distill off dioxane after other volatiles were removed.
After the reaction, the ethyleneglycol can be recovered by refluxing the solution in NaOH - at high purity.

PS I have to admit though that I have no backup on the NaOH de-etherification - but on the other hand I don't see why it shoudn't work! Sounds like a nice method to me anyhow!

Pyrovus - 11-2-2004 at 19:12

I read somewhere about how methane can be prepared by heating sodium acetate with sodium hydroxide:
CH3COONa + NaOH -> CH4 +Na2CO3.

Perhaps an analogous reaction with sodium tartrate could be used to prepare ethylene glycol:
Na2 OOC-CH(OH)-CH(OH)-COO +2NaOH -> (CH2OH)2 +2Na2CO3?

Ethylene Glycol

Hermes_Trismegistus - 11-2-2004 at 21:27

Commonly used in those radiant heating systems they use in concrete builings.

Comes delivered in large drums. Just says ethylene glycol on the MSDS. Had to move some once on a building site. Safety regs say we get to read MSDS on every chem we come into contact with. I just used it as an excuse to catch my breath for five minutes.