i realize that this is probably a stupid question (hence it's in the beginnings section). I want to make sodium carbonate from bicarbonate of soda.
From wikipedia (under solvay process):
Quote:
The sodium bicarbonate (NaHCO3) precipitate from reaction (I) is then converted to the final product, sodium carbonate (Na2CO3), by calcination (160 -
230 C), producing water and carbon dioxide as byproducts:
My question: can i just put some bicarbonate of soda on a baking tray and put it in the oven for a while at this temperature to convert it?
I am unsure as to how vigourous this reaction will be (is it safe to do it as suggested?). Any help will be most welcome.
Note: i have read the other threads about thisMaya - 20-11-2006 at 07:52
Stick it in the oven at 200 C!
Thats all there is to it!
Easiest synth you'll ever do, nothing to it. An eight year old could do it!!
You prolly won't believe its happened but it all converts to sodium carbonate12AX7 - 20-11-2006 at 07:53
Sure. Removing CO2 is usually endothermic so it will require heat (you can also boil it out of a solution, with poor conversion). It will bubble a
bit if the rate is very high (like, heating a spoon of soda in a flame) but I doubt you'll even get that in an oven.
Timsonogashira - 20-11-2006 at 07:59
thanks for the quick responses. any idea on how long it will take to fully convert (half an hour?, more?)Maya - 20-11-2006 at 08:07
stick it in for an hour, depends how much you gotBaphomet - 21-11-2006 at 01:34
Na2CO3 is also available as 'soda ash' or 'pH up' in the pool section of
your local hardware store or supermarket.Drunkguy - 21-11-2006 at 05:46
My advice is to weigh the amount you put in the oven and then calculate how much weight has been lost when you finish. This will enable you to
determine if the reaction is at the end point.Drunkguy - 21-11-2006 at 05:48
Btw 'Soda Crystals' at the supermarket are very cheap but its full of junk. Dont use these.garage chemist - 21-11-2006 at 07:32
Heat the bicarbonate in a crucible until the effervescence (gas evolution indicated by agitation in the powder) ceases. It's good to heat somewhat
above the stated temperature in order to make sure that all of the bicarbonate gets converted.Drone - 21-11-2006 at 08:02
Quote:
Originally posted by Drunkguy
Btw 'Soda Crystals' at the supermarket are very cheap but its full of junk. Dont use these.
For reference, the 'Soda Crystals' at my local shop claim to be > 99.5 % Sodium Carbonate Decahydrate.
If you are looking for a cheap source, it is probably worth a look.Maya - 21-11-2006 at 08:15
<< Heat the bicarbonate in a crucible until the effervescence (gas evolution indicated by agitation in the powder) ceases. It's good to heat
somewhat above the stated temperature in order to make sure that all of the bicarbonate gets converted. >>
Have you ever done this experiment?
There is absolutely no noticable difference is the appearance of the powder before, during or after heating ( much less any visible effervescence )
except for the change in weight12AX7 - 21-11-2006 at 08:34
Like I said, when you heat it quickly, the gas rushes up through the powder and disturbs it. The powder acts like a fluid and it literally bubbles
(think fluidized bed).
Timunionised - 21-11-2006 at 12:04
That experiment is almost worth doing just to see what the fluidised bed looks like. An old tin with the paint burned off over a gas hob will do the
job nicely.
Washing soda is usually reasonably clean- sometimes it has some insoluble crud in it but it is easy enough to disolve the soda, let the junk settle
and pour off the clear solution. Leave this to dry and you will get the white powder that is roughly the monohydrate (IIRC). ( You get the crystals of
the decahydrate first) Drying this in the oven wil get the anhydrous compound. You can dry the decahydrate in the oven but it melts to give a solid
lump that needs powdering and its not very nice to work with.
What do you want it for? The impurities might not matter. I'd only bother making it from the bicarbonate if I wanted to be sure of the purity (At work
I have done that to get a good standard for acid/ base titration).
