Sciencemadness Discussion Board

Nitromethane from Nitromethane/Oil

NaK - 15-1-2021 at 09:06

I have a mix of nitromethane and some sort of synthetic oil, 1:2 and I need to cleanly get out the nitromethane.

Unfortunately I have no idea what is in there, not even what kind of synthetic oil and I also know nothing about synth oils, I would only assume they have a higher boiling point then nitromethane.

So my plan is to do a fractional distillation. Is there anything I should watch out for or a better way to separate the two?

njl - 15-1-2021 at 09:33

If you could get more information on the type of oil that would make separation easier. If the oil is light enough, you might be able to thoroughly mix with water. Once that settles you would have a bottom nitromethane layer, a top oil layer, and an aqueous layer in between.

NaK - 15-1-2021 at 09:42

Interesting, I could try that.
Unfortunately I can't get a datasheet, so I would have to just try it with a small amount.

What I don't really understand though is why the nitromethane would separate out. Is it because water is dissolving into the nitromethane, causing it to not dissolve into the oil? Because if it is dissolved in the oil, why would it just separate out?

[Edited on 15-1-2021 by NaK]

njl - 15-1-2021 at 09:59

Nitromethane is slightly soluble in water. If enough is pulled out of the oil, it could coalesce into a lower layer. Normally you would be correct but in this case since the nitromethane would be separated from the oil by a layer of water, it can't re-dissolve. Sort of like pushing an unfavorable reaction forward by creating an insoluble product.

Fyndium - 15-1-2021 at 11:19

I once investigated vacuum distillation to use as a solvent. Ordinary fractionating should be fine, too. Nitromethane is not quite prone to detonation in such conditions.

http://www.sciencemadness.org/smwiki/index.php/Nitromethane#...

It is actually discussed there a bit. NM-MeOH seem to form azeotrope, but apparently due to their high solubility differences in water, it should be easy to salt out and separate prior distilling it pure. So, like toluene mixtures, first wash it with brine a couple of times and then frac off the NM from remaining oils.

From OTC sources the net cost for a liter of NM seems to be around 40€.

[Edited on 15-1-2021 by Fyndium]

NaK - 15-1-2021 at 12:25

The oil is more dense than water so fractional distillation it is!

Quote: Originally posted by Fyndium  

From OTC sources the net cost for a liter of NM seems to be around 40€.

I was never able to find a source of pure nitromethane that would ship to private individuals. Only bad people use 100% nitromethane and the EU cares for their citizens.

[Edited on 15-1-2021 by NaK]

Fyndium - 15-1-2021 at 13:44

Net price. The devil is in the details.

It's what you get when you extract nitromethane from 25% racing fuel.

Pure NM is not available in EU for privates without licensing. Drag racing guys tend to purchase barrels of that stuff for few € a liter.

NM seems to form azeotrope with water as well. I'm not aware of the stuff's properties, but you might wanna keep an eye for those variables and make some tests first before going into full out distillation. If salting out and other things work, you might be able to get away with one run instead of 5.

NaK - 15-1-2021 at 16:05

oh that makes sense. You misread me too - there is no alcohol in my mixture at all. So if there is nothing in there that interferes with fractional distillation (something that boils at 100C for example) it shoud be pretty easy