monolithic
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Safely quenching sodium?
I have about 50 grams of homemade sodium that I want to get rid of. It's currently sitting under mineral oil and somewhat dispersed into small
globules and contaminated with magnesium flakes.
The simplest solution would be dumping it into a bucket of water or into a waterway but I can't realistically do that because I now live in a more
urban area.
Is quenching with isopropyl alcohol the least energetic OTC reaction I can do here? Can 91% IPA be used for quenching or is the small water content at
risk of making it burst into flames (and igniting the solvent)?
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Rainwater
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Hate to waste it but if you expose it to co2 it will turn into sodium carbonate.
remove the mineral oil and expose it to the air for a long period of time.
The more surface area, the quicker it will react.
"You can't do that" - challenge accepted
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j_sum1
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It seems a shame to lose that much sodium. You can melt it under fresh mineral oil to coalesce the lumps. Adding dioxane helps. Adding a small alcohol
causes it to break into small pieces.
Normal quenching procedure would be controlled addition of ethanol or ipa to abreaction mix with stirring. It eventually forms the alkoxide. You can
be in full control of the reaction rate by adding the alcohol slowly.
With what you have, my inclination would be to cut a small piece (quarter gram) of your Na-Mg mix. Cover with mineral oil and then add your 91%
ipa-water dropwise with stirring. You will soon get a sense of how reactive your mix is, how much fuming occurs, how your container and ventilation
cope. It is possible to react cm sized chunks in pure ethanol in a beaker. But the presence of water changes things.
Go carefully. And scale up slowly.
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monolithic
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That's a good idea, didn't think to keep the sodium under oil and then slowly add the IPA. The immiscibility should provide a buffer of safety. I have
thought about air exposure but I'm paranoid about the high surface area of some of the dispersion and my inability to monitor it 24/7.
I actually tried using 1,4-dioxane (followed the NurdRage method with some success) but it refused to coalesce nicely. I never got around to trying
the other method with hot mineral oil + dropwise IPA. I'd be more inclined to keep it I could separate the magnesium and condense the sodium into a
nice big slug and vacuum seal it. I actually have a nice big 100 g chunk of sodium from a supplier that is sealed in this manner.
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j_sum1
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Patience is the key here.
Even the worst possible process (reacting directly with water in a small room) is manageable at small scale (0.05g).
There is no cause for panic.
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SplendidAcylation
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Would it not be possible to get something useful from it, for instance by reacting it with anhydrous isopropanol to form sodium isopropoxide?
If you washed your sodium and magnesium mixture with an unreactive solvent such as ether, and then added the sodium and magnesium to anhydrous
isopropanol, and refluxed it, you would end up with a solution of sodium isopropoxide, the magnesium pieces could then be filtered out, and the
isopropanol distilled off to yield the base...
Alternatively, you could have some fun and maybe see if you could make some peroxides?
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BromicAcid
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I had a reaction once where I had to prepare sodium isopropoxide. I thought it would be a simple matter of cleaning the sodium and putting it in a
stirred vessel and adding in the isopropanol slowly. The reaction is actually abominably slow. I ended up having to heat and hold at reflux multiple
days and destroyed my flask in the meantime.
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SplendidAcylation
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Quote: Originally posted by BromicAcid  | I had a reaction once where I had to prepare sodium isopropoxide. I thought it would be a simple matter of cleaning the sodium and putting it in a
stirred vessel and adding in the isopropanol slowly. The reaction is actually abominably slow. I ended up having to heat and hold at reflux multiple
days and destroyed my flask in the meantime.
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Ooh yes, I think we actually talked about this a few years back, maybe?
I had a bit of trouble too, I found that the sodium initially reacted with somewhat the same vigour as lithium reacting with cold water, however the
sodium soon became coated with white sodium isopropoxide, which stopped the reaction from progressing.
I had mine in a beaker, and I found that adding excess isopropanol and heating it in the microwave was sufficient to get it to fully "dissolve" within
a relatively short time.
I don't recall whether or not the alkoxide precipitated out upon cooling or whether I had to distill off the isopropanol, anyway, I did eventually
distill off the excess isopropanol, and ended up with a nice white powder.
I'm curious, how did you manage to destroy your flask at refluxing IPA temperatures? 
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BromicAcid
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Took about a week of refluxing, when I was cleaning the flask I noticed that there was waviness in the side walls so I chucked it.
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