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Author: Subject: KHSO4 from NaHSO4
DrScrabs
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[*] posted on 18-4-2019 at 07:10
KHSO4 from NaHSO4


I accidentally bought the wrong salt as ph- in my local hardware store but I´d like to have the K salt.
Do you think there is a way to convert it?
I doubt there is one, I expect upon addiiton of KCl it would result in the the formation of HCl and KNa2SO4.
I plan to use the KHSO4 in the synth of pyruvic acid
http://www.orgsyn.org/demo.aspx?prep=CV1P0475
Maybe K can be substituded for Na, I don´t see any reason why it shouldn´t work. Does somebody have any experience here?
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DrScrabs
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[*] posted on 18-4-2019 at 08:18


I just threw 2g NaHSO4, 2g KCl and 7ml dH2O in a test tube and added a amall amount Al foil, no reaction was visible @ RT
On heating to the boiling point, evolution of H2 and a slight smell of HCl was confirmed by fire and a Iodo starch indicator infused with some NaNo2 .
Reminds me on the method of getting HNO3 from NaHSO4 and nitrate salt.

[Edited on 18-4-2019 by DrScrabs]
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CharlieA
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[*] posted on 18-4-2019 at 16:39


How about swapping the sodium ions for potassium ions using a cation exchange resin? I haven't used one in 50 years so I can't recommend one, but I think some of the brewing suppliers, like Duda sell some.
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DrScrabs
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[*] posted on 20-4-2019 at 05:27


I did not find any wich changes Na for K. Good idea though!
I think in the dry distillation of tartaric acid the Na salt works aswell but the higher mp is not that good for fusing it.
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CharlieA
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[*] posted on 20-4-2019 at 17:38


My understanding of how an IEX works is that it is basically an equilibrium process. If you have resin in the Na+ form, in a column for example, and send a solution of the K+ form through the column, Na+ will be exchanged for K+. I'm sure that there is probably an order of preference in which ion replaces which ion (similar to an electromotive series), but I don't have that information.
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UC235
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[*] posted on 20-4-2019 at 19:26


That pyruvate prep is godawful. If you don't keep everything hot, it turns into one giant foamy ball of acidic caramel that plugs your entire apparatus. I'd stand by with a propane torch. If you add a little GAA, it helps keep the mass more fluid, but is annoying to remove from pyruvic acid later on. There is a sodium-potassium bisulfate eutectic that is fair game and might improve your results. You can also just add an appropriate amount of sulfuric acid to the dibasic sulfate salts and melt them to ensure reaction.

You can buy calcium pyruvate online. Adding sulfuric acid to a solution makes a CaSO4 slurry that can be filtered and vacuum distilled and gives mediocre, but acceptable yields considering it's pretty cheap.

[Edited on 21-4-2019 by UC235]
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DrScrabs
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[*] posted on 25-4-2019 at 12:25


Yes it was! You described it absolutly accurate but I didn´t try with GAA, thought about ethylene glycol.
My final goal is to try to get some acetaldehyde from pyruvic acid with H2SO4. Didn´t find any prep so I just have to try. From tartaric acid it is much cheaper than Ca.pyruvate, I didn´t find a source other than in the US but shipping is quite expensive, no good source within the EU yet. China has a quite large minimum amount to buy. Tartaric is @9eur/Kg local, NaHSO4 @5/1.5Kg, acetaldehyde is at 50/l+shipping(24eur) atm.


[Edited on 25-4-2019 by DrScrabs]
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