CHRIS25 - 8-2-2013 at 01:52
I need Potassium Citrate. So I am making potassium bicarbonate to mix with citric acid. My source of CO2 will be 40% Acetic acid and Sodium
bicarbonate. So even juggling around with my air pump and pen on paper I can not figure out a method how to bubble CO2 into the flask of KOH where
the CO2 is coming from a separate flask containing the acetic acid and Sodium bicarbonate. I thought about hooking up my car exhaust - narrowing the
pipe into an extra big container with a kilo of KOH to give me a lifetime supply....just kidding. Obviously this is easy with the right equipment,
but I have to improvise the best I can, at home, since I do not have those lab essentials. (I know buying is easy, but if you know me by now you
know that I want to make things if it is possible). So does anyone have an idea please?
[Edited on 8-2-2013 by CHRIS25]
weiming1998 - 8-2-2013 at 02:22
Just add your KOH to citric acid. It will make potassium citrate.
Vargouille - 8-2-2013 at 02:25
I would suggest having your stoppered CO2 generator lead into a suckback trap (an empty Erlenmeyer should suffice) which leads into your solution of
KOH. Don't forget to put a tap on the KOH solution so that pressure doesn't build. There's probably a better way to do this, but this is one of the
simplest.
EDIT: But yes, simply adding the KOH is a faster way to get to potassium citrate, but I get the feeling that you're planning on finding the end-point
by the end of bubbling, ey?
[Edited on 8-2-2013 by Vargouille]
CHRIS25 - 8-2-2013 at 05:00
There you go...me a simpleton again, It never occured to me to just add KOH and Citric together. That underlines my lack of knowledge - no matter how
much reading I do.... It's quite annoying really that I did not see this myself.
Vargouillie - I dont' understand what you mean. I understand titrations and end-points, but how could I learn anything if I were to still, for fun,
bubble CO2 through the KOH?
Vargouille - 8-2-2013 at 12:12
I don't quite understand. Are you asking me how to find an end-point for a reaction with a bicarbonate? The reaction is done when no more off-gassing
occurs. It's somewhat simpler than measuring out the reagents, although it is less accurate. The process I put forward would be useful if you wanted
to make potassium bicarbonate (useful for a bicarbonate more soluble in less polar solvents; also useful for compounds subject to base-catalyzed
hydrolysis).
CHRIS25 - 8-2-2013 at 15:53
It's ok Vargouille, thanks.
AJKOER - 9-2-2013 at 08:43
Of course, if you do not have KOH on hand, but do have KCl, ammonia, soda water (H2CO3), Citric acid and still want Potassium Citrate, he is a
possible path.
KCl (aq Conc) + NH3 + H2CO3 = KHCO3 (s) + NH4Cl (aq)
Check solubilites to see if you can move this reaction to the right and separate products as indicated. Based on the Solvay Process (see http://en.wikipedia.org/wiki/Solvay_process ). Then combine Citric acid with the KHCO3.
Another path better separation but slower, pour molten Pb into water. Add Citric acid and H2O2 and see if it slowly dissolves over a day or so. To
the solution of Lead citrate add KCl. The PbCl2 should precipate out.
Probably should have an excess of Citric acid as if a soluble Lead citrate complex did form it could increase the solubility and move the reaction
forward. Note, some history, Seymour S. Kety first used Lead citrate to relieve the children of their lead poisoning as soluble citrate would flush
the lead out of through urination (1st chelating agent, see http://en.wikipedia.org/wiki/Seymour_S._Kety ).
[Edited on 9-2-2013 by AJKOER]
CHRIS25 - 10-2-2013 at 00:26
Hi AJKOER, both of these reaction paths - for completely different reasons have given me something to consider, (I have loads of KOH so no problem).
Love history of chemicals thanks for the Seymour link.
vmelkon - 10-2-2013 at 17:38
If you were to actually do it the original way you intended (NaHCO3 + acetic acid), you would get droplets carried with the CO2 gas into your KOH. You
would contaminate it with sodium salts. You would need a filter.