Sciencemadness Discussion Board

Storing Sodium Metal

shivam - 29-10-2015 at 02:10

Hey guys

I have 100 grams of very old sodium Metal stored in some sticky brown liquid which I'm assuming is crude kerosene or some other Petroleum oil product.
I'm going to clean it and store it properly.
I don't have any paraffin oil.
I do have kerosene. But just so that i can dry my sodium quickly before using, can I store it under Toluene?
And if I can use toluene , are there any negative sides?

Thanks in advance..

JJay - 29-10-2015 at 10:17

You can store it under toluene... I don't keep sodium on hand unless I have plans for it, but when I do, I keep mine under mineral oil. You could wash the mineral oil or toluene off with whatever solvent you are using before using the sodium.

I'd be careful about making any assumptions about the brown liquid.

ParadoxChem126 - 29-10-2015 at 11:50

The main issue with long term storage in toluene is that it is flammable. If there was an uncontrolled sodium fire, the presence a flammable solvent would only exacerbate the problem. People use mineral oil because it is cheap and (relatively) nonflammable.

While it is true that toluene can be used for temporary storage or for rinsing the sodium, mineral (paraffin) oil would be a better choice for permanent storage, if you have access to it.

Detonationology - 29-10-2015 at 12:04

Mineral (paraffin) oil is accessible in most grocery stores and pharmacies in the US. Perhaps, if that is out of the question, petroleum jelly should would just as well as well as mineral oil, besides the greasy mess.

Upsilon - 29-10-2015 at 14:17

Quote: Originally posted by Detonationology  
Mineral (paraffin) oil is accessible in most grocery stores and pharmacies in the US. Perhaps, if that is out of the question, petroleum jelly should would just as well as well as mineral oil, besides the greasy mess.


Oh believe me, mineral oil is just as greasy and messy - I store my magnesium ribbon in a pickle jar under mineral oil, and fishing a piece out of that mess is one of the things I dread most about experimenting. Still, better than having nasty useless oxidized magnesium.

chemrox - 29-10-2015 at 15:25

Someone addressed this before. I believe he stored his in sealing wax. I think it went like this:
Remove from solvent, wipe off solvent, shave any oxidation off and dump into liquid wax, remove and cool.

aga - 29-10-2015 at 15:30

Quote: Originally posted by Upsilon  
I store my magnesium ribbon in a pickle jar under mineral oil, and fishing a piece out of that mess is one of the things I dread most about experimenting. Still, better than having nasty useless oxidized magnesium.

Mine is oxidised to buggery, having been left out in the open.

A few runs through some sandpaper and it is all shiny and new, ready to be vigorously reacted with whatever.

Life is hard for Mg.

Edit:

In the case of Mg (in a home lab) oxidation isn't a problem, just a way to preserve the larger part of the reagent for later use.

[Edited on 29-10-2015 by aga]

Upsilon - 29-10-2015 at 15:40

Quote: Originally posted by aga  

Mine is oxidised to buggery, having been left out in the open.

A few runs through some sandpaper and it is all shiny and new, ready to be vigorously reacted with whatever.

Life is hard for Mg.

Edit:

In the case of Mg (in a home lab) oxidation isn't a problem, just a way to preserve the larger part of the reagent for later use.

[Edited on 29-10-2015 by aga]


Well, you rub off the oxide layer, I rub off the mineral oil layer. To each their own :P

shivam - 29-10-2015 at 21:32

Thanks for suggestions guys
The problem is that I have no access to Pure mineral oil in India (there must be, I'm just not familiar with the sources)
I guess i can use Baby oil (The Johnson's & Johnson's kind)
I just wasn't sure about using scented baby oil, because of the additives added in it
Otherwise, I think I'll rule out the toluene option considering the fire risk that ParadoxChem126 mentioned..

j_sum1 - 29-10-2015 at 21:55

On magnesium...
I keep a dozen or so rolls in a plastic screw-top peanut butter jar. It retains its shininess quite well and I haven't had significant issues.
On the occasions that I have wanted cleaner Mg ribbon, a few seconds in some HCl and then rinsed off with water and dried with a hairdrier does the trick. I am sure that a higher standard is required with Grignards but I am not doing those.

On sodium, there must be many suitable solvents that it can be stored under. I have really only seen mineral oil / paraffin used. But I have heard of everything from toluene to kerosene to solid blocks of wax. I think that low viscosity and slightly volatile anhydrous solvents are likely to be the least messy. But that also implies flammability.

The cleverest solution I have seen is to store Na in a syringe and use that to extrude wire when needed. Let's see if I can find a video...
https://www.youtube.com/watch?v=btvQdW4fXJE

My own sodium is in the post as we speak. When it arrives, it will be stored in its tightly-sealed can until I actually need it. Then it is likely to be in a jar under mineral oil.