What is this liquid?

[Justonium]

I made sodium acetate by mixing distilled white vinegar with baking soda, with a little excess vinegar so that all of the baking soda reacted. Then I heated it on the stove until all of the water evaporated. This formed anhydrous sodium acetate. Upon farther heating, this turned completely into a black liquid that smelled TERRIBLE. Sodium acetate decomposes before melting (according to Wikipedia) into acetone and sodium carbonate. Acetone would definitely explain the reeking smell, but what is the liquid? Sodium carbonate remains solid sodium carbonate up to 851C, which I know I didn't reach on my stove. Acetone boils at well under the decomposition of sodium acetate, so the only logical explanation I can think of for the liquid is that the acetone decomposed farther upon contact with my hot pan, making another organic compound with a higher melting point. When I poured this yucky liquid into a pot of water, it immediately solidified into a gray solid that commenced to dissolve. Sodium carbonate was dissolved in the liquid, but what was the liquid it was dissolved in? The black color may be due only to burnt impurities from the vinegar.

 

EDIT: I want to make sodium metal from this liquid through electrolysis, but first I want to know what the heck I'm dealing with.

Edited May 21, 2009 by Justonium

[hermanntrude]

please refer to this thread

 

it doesn't really matter what you've made, you wont be able to make sodium from it, although you might be able to set your house on fire or choke yourself from lack of experience.

[Justonium]

Come on, you're telling me it doesn't matter what I've made? Of course it does. I've done an experiment and now want an explanation for the results. As for making sodium, why do you think it would not work? If I do indeed have sodium carbonate dissolved in an organic solvent, then electrolysis should yield sodium, as there is no other ion competing with it such as hydrogen. I don't know this for sure, but is there a problem with trying? Don't criticize me please; if you don't have an answer, please don't post here.

[hermanntrude]

Come on, you're telling me it doesn't matter what I've made? Of course it does. I've done an experiment and now want an explanation for the results. As for making sodium, why do you think it would not work? If I do indeed have sodium carbonate dissolved in an organic solvent, then electrolysis should yield sodium, as there is no other ion competing with it such as hydrogen. I don't know this for sure, but is there a problem with trying? Don't criticize me please; if you don't have an answer, please don't post here.

 

it's very hard to reduce sodium. organic solvents are nearly all flammable, so dont try putting a current through them, and bear in mind that a LOT of other reactions will occur before sodium will accept that extra electron... perhaps a few you (or I) havent heard of.

 

Also bear in mind that if it was that easy to make sodium in that way, people would do it all the time.

[UC]

Come on, you're telling me it doesn't matter what I've made? Of course it does. I've done an experiment and now want an explanation for the results. As for making sodium, why do you think it would not work? If I do indeed have sodium carbonate dissolved in an organic solvent, then electrolysis should yield sodium, as there is no other ion competing with it such as hydrogen. I don't know this for sure, but is there a problem with trying? Don't criticize me please; if you don't have an answer, please don't post here.

 

Water will preferentially form hydrogen and oxygen gas at the cathode and anode respectively. To make sodium, there has to be just about nothing else around that might be reduced instead.

 

There are 4 ways to make sodium that I'm aware of:

 

1: electrolysis of molten sodium chloride

2: electrolysis of molten sodium hydroxide

3: electrolysis of a soluble sodium salt with nonreactive anion in pyridine. (I think I remember this being discussed)

4: Make use of Le Chatlier's principle and distill it from a mixture of calcium metal and a sodium salt brought up to the melting point of calcium.

 

None of these methods is readily accessible nor suitable for the amateur, unless you have an excellent understanding of electrochemistry and some serious shop skills, as well as a considerable amount of money for construction materials.

 

Are you sure that your sodium acetate was anhydrous? It does form a solid trihydrate that then melts upon heating. Vinegar also contains all sorts of crud like a small amount of acetaldehyde, bits of dead yeast, possibly sugars, etc. that will form condensation products and junk when heated, giving you that black color. Sodium carbonate is insoluble in acetone last I checked, and any acetone evolved would have been as vapor at the required temperatures.

Edited May 21, 2009 by UC

[Justonium]

Try and focus on what the liquid actually is; if I can't make sodium from it it's no big deal, I have plenty of NaOH, but I really want to know what I've made. Does anybody know at what temperature acetone decomposes, and what it's decomposition products are? If I can rule out acetone then I know I've just made some vinegar "tar," basically just junk. It does seam strange that the acetone would decompose before it left the pan as a gas, so, I dunno, any ideas on what made this liquid would be helpful.

 

Yes my sodium acetate was anhydrous; I started with the hydrate, and then it decomposed into an aqueous solution, which boiled off. This isn't necessary information, but if you're interested, I boiled the sodium acetate down until it crystalized when blown on, and then removed it all and made it "freeze" solid for a demonstration. After that, I felt like playing around so I continued as already stated above.

Edited May 21, 2009 by Justonium

[hermanntrude]

generally, in my experience, when the product is (a) unexpected and (b) black, it means it's most likely some crappy decomposed mixture of crap, not worth putting a name to.

 

for crying out loud please give up on the sodium thing. sodium hydroxide wont help either. It's dangerous and incredibly difficult. and you obviously don't have the necessary experience. I'm a chemistry instructor with a PhD in nanomaterials and I would try it either.

[m791270]

OK, I know that this thread is 4 years old, but I had to put my two cents in since it was just about the only place on the net where I could find a reference to "molten sodium acetate".

 

Justonium, I could not agree more with your attitude that just because your experiment yielded this stinking black oil instead of the product you were after does not mean that it is unimportant. All of the negative replies that you got were written by people who either A) didn’t read your post fully and only saw the last line where you mentioned elemental sodium production, or B) didn’t have a clue as t o what you got and were trying to come up with something to say that sounded more intelligent than “I don’t know”.

 

I was trying to produce sodium acetate just for the hell of it (yes, I am a chemistry power nerd and I do these kind of things for fun).. I produced the compound by the reaction of vinegar and sodium carbonate. I allowed it to air dry and was getting beautiful crystals of sodium acetate when I got bored and decided to re-dissolve it water and heat it up on my kitchen has stove in a metal pot. I heated it up until I got anhydrous sodium acetate and was about to stop when I noticed this black, oily liquid coming out from under a bed of crystals on one side of the pot.

 

Curiosity got the best of me, and so I let it keep on heating when suddenly all of the sodium acetate crystals “melted” down into this stinking black oil. The smell given off was NOTHING like acetone , and so I then decided to quickly cool the whole mess in a larger pot containing ice water.. The black oil solidified into a metallic looking substance which DID end up dissolving in water to create on opaque, black solution I have absolutely no idea what it is, and is I ever find out I will certainly post it on this thread.

 

Justonium, don’t let the scientific establishment wear you down with their laziness and lackadaisical attitude. Some of the greatest scientific discoveries were made by accident and by someone with curiosity investigating the results of a “mistake”.

Edited July 22, 2013 by m791270