Nitric Acid Synthesis


Nitric Acid (HNO₃) is a much used acid in the field of explosives,
that's why it's interesting to be able to produce it in a fairly pure form.


The stuff you need to prepare HNO₃:

- 50 ml of >95% H₂SO₄ (sulfuric acid)
- your calculated amount of nitrate
- a 1000 ml beaker or equivalent
- a 100 ml beaker or equivalent
- some plastic sheet that can stand hot HNO3 (test it)
- a rubber band


Click the image below to see my contraption made from these materials


H₂SO₄ + xNO₃ => HNO₃ + xHSO₄

The nitrate I used was NH₄NO₃, so that gives me:

H₂SO₄ + NH₄NO₃ => HNO₃ + NH₄HSO₄

NH₄NO₃ = 14 + 4x1 + 14 + 3x16 = 80
H₂SO₄ = 2x1 + 32 + 4x16 = 98

So we round those off because my H₂SO₄ contains 2% water anyway,
and we get 80 grams of NH₄NO₃ for every 100 grams H₂SO₄.

You need to keep the little beaker in the middle of the big beaker, otherwise you're just gonna waste
alot of materials, energy and time. For this purpose, I made a support from Al-foil. (not shown on vid)

Once the beaker is secured, you pour the nitrate and the H2SO4 mix around the small beaker.
Then place the plastic foil (make sure it's strong enough) over the whole thing, making sure it bulges in alot,
hanging just over the little beakers mounth in the middle. Then secure it with the rubber band.
And after that, fill it with ice water.

Now you're ready to give this setup some heat, start slowly, and monitor the progress.


You'll notice alot of red fumes forming as the acid evaporates...


and drops condensing on the foil, run down to the deepest point, falling in the small beaker.


I didn't have the time to let this go on for very long, but it got at least an half hour on the hotplate.



I can't say I'm very happy with the yield, but it's not a complete failure anyway ...

Density measured out at 1.22 grams/cm³

100% HNO3 is 1.58 grams/cm³

I'm gonna try this again with KNO₃ ...

===============================================================================

Okay, retry:

My main problem was the heat control in the last setup, that's why I used
a hot water bath now, keeping the temperature between 60 and 65°C.

Also note I'm not using heat-proof glass this time, making it even
easier for a random DIY chemist :)



Here you see drops of HNO3 condensing on the inside of the foil
You don't need to refresh the ice al the time, just make sure you don't run out of water.



At this point, the temperature is about 60°C

This is my yield after 2 times 12 hours in the hot water bath:


6 ml of clear HNO₃ that weighs 9-10 grams (I wish I had a better scale)

Thus density measured out at more then 1.5 grams/cm³ !!!
Purity is okay, now let's scale this thing up to give me some quantities :D


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