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Author: Subject: The simplest preparation of sulfuric acid?!
NEMO-Chemistry
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[*] posted on 9-1-2018 at 17:44


Its mainly wiki that got me thinking, looking at the solubility and the fact the potassium salt acts like two separate substances in solution, also potassium bisulphate is often made as potassium sulphate with sulfuric acid added, the sodium salt is very different, no solubility data for alcohols etc.

But more than that, every paper where its mentioned has only mentioned the potassium salt, none mention the sodium. Then finally we get to potassium carbonate salts ethanol much much better than sodium carbonate. There should be as much difference as there is.....

I got a knock back from the chem company! no idea why but apparently they are not stocking it now??? Strange as they said it was dispatched.

So will get potassium nitrate and make some nitric acid :D
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clearly_not_atara
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[*] posted on 11-1-2018 at 17:09


Potassium salts are generally less hygroscopic than sodium salts, which may be an advantage in this case. It's possible that sodium sulfate catalyses the formation of ethylsulfuric acid and its salts. Potassium bisulfate is also almost twice as soluble in water as the sodium salt, which probably increases the yield significantly -- both sodium and potassium sulfate are very insoluble in alcohol.

Nice work j_sum1. Methylated spirits usually contain a few percent butanone these days IIRC. I don't think that would interfere with the rxn too much but it's there to prevent distilling them to get ethanol.

EDIT: Ammonium bisulfate may work even better -- the aqueous solubility is very high, about 200g / 100 mL at 300 K, and in some cases the addition of excess ammonium bisulfate to water precipitates (NH4)3H(SO4)2 (Beyer&Bothe 2006, attached), before any alcohol is even added! Ammonium sulfate is famously insoluble in organic solvents, as well.

[Edited on 12-1-2018 by clearly_not_atara]

[Edited on 12-1-2018 by clearly_not_atara]

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[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 13-1-2018 at 13:19



The bisufate in methylated spirits has increased in density by 15% and become rather viscous.

A sample showed strong acidity and a considerable reserve of it.

This is consistent with the description of the bisufate as slightly soluble in alcohol, but decomposed by it, in the CRC manual. The total acidity of the solution exceeded anything that the slight solubility of the bisulfate could have contributed by many times.

The solution was returned to the bisulfate to see if any further reaction occurs, as monitored by testing the density.
I think the possibilities of bisulfate systems for obtaining sulfuric acid merit some thought and attention. At least a bit more than they've received so far.

@clearly_not_atara, Where did that reference for sodium bisulfate being 'very insoluble' come from?
Doesn't seem like there'd be any reaction in that situation to me, at least not on a reasonable time scale.
Just can't see how the reaction could proceed into the crystals much without some degree of solvation.
Is there some phenomena I may be unaware of here?




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[*] posted on 13-1-2018 at 20:06


If you reflux sodium bisulfate and ethanol, it forms some sodium sulfate and some ethyl sulfate. This was claimed to be an extremely high-yielding reaction in a U.S. patent but didn't seem to be when I tried it with pool-grade sodium bisulfate and anhydrous ethanol, and I'm not exactly sure why. It definitely does work to some extent, though.

I don't see why you couldn't distill off the ethanol and then heat the ethyl sulfate to 130 or so and distill off ether, leaving behind sulfuric acid. You probably won't get all of the ethanol out that way, and as the temperature increases you'll distill off ethene and then ethyl sulfate (probably some diethyl sulfate also). There may be some sulfuric acid left when you reach its boiling point, though.

[Edited on 15-1-2018 by JJay]




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[*] posted on 14-1-2018 at 02:33


I cant get hold of potassium bisulphate at the moment, my normal sources dont have it or wont sell it!
I have sodium bisulphate, how can i convert it?

As a side note I have real trouble getting most potassium salts including carbonate!! I am slightly restricted in which companies i can use, but could do with confirmed sources in the UK for potassium Bisulphate. Ebay isnt an option for this one, i have to buy this through the company, on advice i shouldnt buy chemicals for the company via ebay.
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