Sciencemadness Discussion Board

Nurdrage makes HBr

Syn the Sizer - 26-3-2020 at 08:26

In a video Nurdrage made HBr by mixing NaBr and NaHSO4. You end up with HBr and Na2SO4. Would this process also work with a nitrate salt to make HNO3 and trisodium phosphate to make H3PO4? If it works do the cations need to be the same element, for example, could you use KI and NaHSO4 to make HI and NaKSO4 or is the different in reactivity between sodium and potassium an issue. How about NH4NO3 and NaHSO4?

Thanks
Syn

Bedlasky - 26-3-2020 at 08:47

I think that there isn't any problem with it.

Fery - 26-3-2020 at 09:11

You won't be able to easily distill out H3PO4.
For HNO3 I suggest reaction like NaNO3 + H2SO4 -> HNO3 + NaHSO4 and distill out HNO3 (the problem during distillation here is the thick slurry of the NaHSO4).
Producing HI is tricky, I suggest e.g. KI + H3PO4 and distill out HI. Do not use H2SO4 as it oxidizes the product to I2 (the same oxidation happens in production of HBr using H2SO4 where some of HBr is oxidized to Br2). Other ways are e.g. H2S + I2, or I2 + tetrahydronaphtalene, or I2+P+H2O. H2S very toxic, tetrahydronaphtalene and P unable to buy without business ID. P is watched substance so you can expect controls even you have business ID and you were able to buy it. I2 + hydrazine works too, hydrazine is very toxic.

UC235 - 26-3-2020 at 09:40

You can't distill H3PO4. It is heated in furnaces to produce polyphosphoric acid and is more or less completely nonvolatile.

There are plenty of videos on making HNO3 like this. NH4NO3 is the easiest IMO because the ammonium bisulfate is rather soluble and you can stir better while distilling.

chornedsnorkack - 26-3-2020 at 10:32

Quote: Originally posted by UC235  
You can't distill H3PO4. It is heated in furnaces to produce polyphosphoric acid and is more or less completely nonvolatile.

Technically speaking, the boiling point of high boiling azeotrope is about 850 Celsius. Which is a lot compared to sulphuric acid azeotrope (338 Celsius) even though it is low compared to the boiling point of boron oxide (about 1850 Celsius) or of silicon dioxide (about 2800 Celsius).

Syn the Sizer - 26-3-2020 at 10:50

Awesome, Thanks for all the replies, they answered my questions. I knew H3PO4 had such a high boiling point and should have considered that before asking the question. I ultimately was just looking for an easy way to get HNO3 without using H2SO4. I can't find H2SO4 drain cleaner anywhere in my city and the battery shops I talked to won't sell battery acid to general public, but NaHSO4 is found everywhere.

chornedsnorkack - 26-3-2020 at 22:07

Also, phosphoric acid is probably the highest boiling acid I know. Because B2O3 and SiO2 don´t contain significant amounts of water.

The azeotropic acid, the one that boils around 850 Celsius, is slightly towards P2O5 of HPO3.

Now, for the oxide end, the thing is that P-O bonds are slow to equilibrate.
On rapid condensation in absence of catalysts, molecular P4O10 condenses which freezes at 360 and boils at 423 Celsius. But on slow heating with catalysts, P2O5 polymerizes, and the boiling point then seems to be around 700 Celsius.

There are no crystal solids between H4P2O7 and P4O10. Those melts congeal to amorphous glasses.
Does anyone know the approximate congealing range of the azeotropic metaphosphoric acid?

RogueRose - 27-3-2020 at 01:05

Isn't there a process of making HNO3 from oxalic acid?

Found the thread... IDK if it works, there are some video's on it as well, but I didn't find them, maybe they are gone. I'll have to look back through my video archive.

http://www.sciencemadness.org/talk/viewthread.php?tid=87036

HNO3 from NaHSO4
https://www.youtube.com/watch?v=VLOY-Jp2w1I

[Edited on 3-27-2020 by RogueRose]

Syn the Sizer - 27-3-2020 at 09:02

Thanks again for the continued replies, this forum never disappoints. I found a place that would actually sell me HNO3 in Canada but at the moment its out of my price range, and to be honest I think I pissed them off with a comment I made so they probably won't sell to me anymore anyway.

Thanks
Syn

chornedsnorkack - 28-3-2020 at 00:38

How soluble is P2O5 in B2O3?

If you heat a phosphate with molten B2O3 in the range of say 700...1000 C, how effectively does the higher volatility of P2O5 allow boiling off the phosphorus and condensing it as P4O10 under 423 C?

PirateDocBrown - 28-3-2020 at 12:18

Doug's Lab had a good video on nitric acid production, and there are others, as well.

You don't want to make nitric from ammonium nitrate, as the residual ammonium salts can dissociate ammonia gas, which can contaminate your product. Use sodium or potassium nitrate. Even strontium nitrate will work. But the calcium nitrate that's usually available also has ammonia in it, leading to the same problem.

Syn the Sizer - 28-3-2020 at 13:10

Quote: Originally posted by PirateDocBrown  

You don't want to make nitric from ammonium nitrate, as the residual ammonium salts can dissociate ammonia gas, which can contaminate your product. Use sodium or potassium nitrate. Even strontium nitrate will work. But the calcium nitrate that's usually available also has ammonia in it, leading to the same problem.


That makes sense. There is a garden shop in the city has what they claim to be pure calcium nitrate. But I haven't been able to find potassium or sodium nitrate OTC here.