[rama1danhany]

Hi all,
I wish if I can find an experimentalist who can answer this question. I am physical chemist who would like to prepare sodium ethoxide from sodium and ethanol. my question is how to handle sodium (clean, prevent it from burning...etc) before I add it to ethanol?


Thanks


Hany

[lavoisier]

The best thing would be to handle it under dry, inert atmosphere, in a glove box for instance.
But if you don't have the appropriate equipment, the only precaution you may take is to be quick!
Some books say that you shouldn't cut Na (or even worse, K) with knives, because it can generate an explosion. I just report it, I don't know how true it is.

It would be useful to know what purity you need for your NaOEt.
If you need to have no hydrocarbons, you must wash your sodium (which is usually stored under heavy hydrocarbons) with pentane and dry it before use.
If you need to have strictly NO NaOH, you need extra dry EtOH and extra clean sodium, i.e. you do need the glove box.

Another trick that I was taught for making alkoxides is that if you make your pieces of metal as flat as possible, they will react better. I tried with lithium, and it's true.
It may look weird to see a chemist hammering a piece of highly reactive metal, but you know how organic chemists are... we just can't do without some folklore.

[Ψ×Ψ]

How much do you need?  Also, depending on concentration and purity needed, you might not need to worry too much.
Glove box might not be necessary.  Take a chunk of sodium out of the grease it's usually stored in, using something like a spatula to cut it.  It's pretty soft.  Quickly transfer to a small beaker containing hexanes.  Cut into small pieces with spatula while still under hexanes.  Add pieces to ethanol.  (Do not add ethanol to sodium.)  Quick & dirty, but it works.  On a small scale, it isn't too dangerous. 

[rama1danhany]

Hi guys,
Your inputs are really helpful, I appreciate.

Thanks

[alphahydroxy]

yeah - last time i did this (a few years ago now) it was very much a case of chopping up sodium with a butter knife giving it a quick rinse in hexane and putting it into a beaker of ethanol. worked a charm!

[lavoisier]

Maybe not in a beaker, but in a closed flask under inert atmosphere.
Unless you like fireworks

[alphahydroxy]

Maybe not in a beaker, but in a closed flask under inert atmosphere.
Unless you like fireworks

nope - did it in a beaker!

This was in australia - land of cowboy chemistry!

[lavoisier]

OK, so when we see people from Australia and they look like they're sunburnt, it actually wasn't the Sun, but hydrogen flashes from beakers of sodium+ethanol.
Thanks for letting everybody know. I'm sure many people can't wait to try it themselves.

[alphahydroxy]

OK, so when we see people from Australia and they look like they're sunburnt, it actually wasn't the Sun, but hydrogen flashes from beakers of sodium+ethanol.
Thanks for letting everybody know. I'm sure many people can't wait to try it themselves.

My sarcasm detector just went off...

It's people's own problem if they can't be bothered to check up on procedure before they go ahead with something - it's chemistry, not playschool...

This was actually an undergraduate lab script btw, under the guidance of a PhD demonstrator and a professor, not just me wanging reactive metals around on my own!

[Ψ×Ψ]

My likewise-quick-and-dirty prep is also derived from a lab class experience under the direct guidance of the prof.  No real problems with it, either.

[Custos]

OK, so when we see people from Australia and they look like they're sunburnt, it actually wasn't the Sun, but hydrogen flashes from beakers of sodium+ethanol.
Thanks for letting everybody know. I'm sure many people can't wait to try it themselves.

The reaction between ethanol and sodium isn't that reactive, not like water and sodium. If the ethanol is anhydrous, and the volume is large enough to dilute the heat generated, you can easily dissolved sodium in ethanol safely without an inert atmosphere. I'd use a conical flask or quickfit rbf rather than a beaker, but you could get away with it.

[lavoisier]

Sorry, I didn't mean to be rude.
It's just that I was trained to work to high safety standards, and I think this is a sign of respect towards myself in the first place.

If you're not bothered by having in front of you an open beaker with an explosive mixture of hydrogen and air, plus a flammable solvent, a corrosive and flammable metal, and a base that can dissolve your eyes in minutes, fair enough, it's your life...
Besides, if you leave sodium ethoxide in air too long it will absorb moisture and become NaOH, so doing the preparation in open air is wrong even on a strictly practical basis.

The other element to consider is that the original post was from a physical chemist who specifically asked for expert advice on this preparation. He's probably not too familiar with experiments in organic chemistry, therefore I think he should proceed very cautiously.

I'd rather sound like a chicken than induce someone to do things that can harm him.