Sciencemadness Discussion Board

C + NaOH experiment - Did anything happen?

Draeger - 28-6-2020 at 13:18

So, I decided to do an experiment to see if a result in reply to a parameter I input on a random website that seems to be able to figure out the products of a reaction on it's own actually works. The website often isn't that reliable.

I mixed 10g of NaOH and 1g of charcoal together in a mortar and for some reason could only achieve a granular mix and was not able to powderize it.

I mixed them in this ratio:
6 NaOH + 2 C → 3 H2 + 2 Na + 2 Na2CO3


I then poured a tiny amount of the composition into a graphite crucible and heated it with a (pretty weak) burner. Not a lot happened except for small waves of heat and an increase in the glow of the composition which I only presume to be the coal igniting. After about ten or maybe 20 seconds of heating the composition, I stopped.

Out of the composition stuck white plates, which I only presume to be sodium hydroxide that melted. As a last test I poured water into it to see if a reaction would occur. I think I might have heard slight bubbling, but it might have just been air trapped in the NaOH, or, since it would be very unlikely sodium metal would survive the burner flames, maybe it was sodium peroxide?

I know it would be very unlikely that anything could've happened, but before I just discard it all I want to hear other's thoughts.

[Edited on 28-6-2020 by Draeger]

Ubya - 28-6-2020 at 14:22

nothing probably happened, even if some atoms of sodium managed to form, they reacted with the oxygen in the air (you didn't say that this was performed in a sealed container flushed with argon)

Draeger - 28-6-2020 at 14:50

Quote: Originally posted by Ubya  
nothing probably happened, even if some atoms of sodium managed to form, they reacted with the oxygen in the air (you didn't say that this was performed in a sealed container flushed with argon)

Ah. Okay. Thank you.

elementcollector1 - 28-6-2020 at 15:50

This technically counts as an example of carbothermic reduction, and is similar to how sodium was first isolated from its carbonate. So yes, in an inert atmosphere and at high enough temperatures, this would certainly work.

Of course, actually testing this would require you to create an apparatus to deal with any hydrogen gas produced, keep an inert atmosphere going and provide enough heat to maintain the reaction (carbothermic reductions are rarely as self-energizing as aluminothermic reductions), as well as prevent the sodium from boiling off in the process (or alternatively distilling it to somewhere else for collection). Not terribly practical, all things considered.

Eddie Current - 28-6-2020 at 16:13

Quote: Originally posted by elementcollector1  
This technically counts as an example of carbothermic reduction, and is similar to how sodium was first isolated from its carbonate. So yes, in an inert atmosphere and at high enough temperatures, this would certainly work.


Do you have a paper on this original process?

I would be interested to know the reaction temperature.

Draeger - 28-6-2020 at 16:23

Quote: Originally posted by elementcollector1  
This technically counts as an example of carbothermic reduction, and is similar to how sodium was first isolated from its carbonate. So yes, in an inert atmosphere and at high enough temperatures, this would certainly work.

Of course, actually testing this would require you to create an apparatus to deal with any hydrogen gas produced, keep an inert atmosphere going and provide enough heat to maintain the reaction (carbothermic reductions are rarely as self-energizing as aluminothermic reductions), as well as prevent the sodium from boiling off in the process (or alternatively distilling it to somewhere else for collection). Not terribly practical, all things considered.

Thank you. Sounds like hell actually making such an apparatus. Not something I'll try. Hydrogen gas and sodium vapor sounds like a bit too much energy able to be released at any mistake.

elementcollector1 - 28-6-2020 at 16:28

Quote: Originally posted by Eddie Current  


Do you have a paper on this original process?

I would be interested to know the reaction temperature.


Can't find a specific paper as a source (best I found was an autobiography on the inventor, which would likely be a tedious read), but Wikipedia cites 1100 oC as part of the Deville process for making aluminum, starting with sodium from sodium carbonate and carbon. Sodium vapor was likely then distilled over, at those temperatures.

https://en.wikipedia.org/wiki/Sodium#Commercial_production

Refinery - 28-6-2020 at 23:04

Na reacts with hydrogen gas to form sodium hydride, hence probably hydroxide cannot be readily converted into metal, unless the reaction would occur below the formation temp. Na2CO3 on the other hand turns into oxides of carbon, which leave the reactor.

Na2CO3 + 2 C → 2 Na + 3 CO


1100C might be too much temp for high pressure propane burner. Theoretical temp is 1980C, but in no way even small metal object go much beyond 1000C when immersed inside the flame. On the other hand, a SS vessel placed in ceramic wool insulated oven would work if the temp is achieved to start the reaction. An exhaust tubing through the wall could be used to collect the sodium metal, because it melts at 98C so the residual heat and thermal mass will keep it flowing until it drops to collect into the receiving vessel.

I could actually look into this reaction. I should have a proper vessel around, with few fittings to be done. It doesn't work though, if I can't reach the temp. It could be done with charcoal, but I've managed to melt a couple of SS pots with it due to the heat. Possibly the reactor could be pre-heated with decent coal bath and then more heat added with propane torch.

Refinery - 3-7-2020 at 06:36

I gathered some old stuff and found this. It could be viable for above reaction.