Concentrate Nitric Acid ? _poormansnitric_

[Geo]

I have read a bunch of the posts in this section, to date I have not used the recipe. One issue I have seen mentioned is the possibility of a beaker breaking while concentrating H2So4. So being who I am, I had an Idea that I believe can eliminate the danger. Place the beaker in a sand bath while boiling off excess H2o. The sand will distribute the heat evenly and allow for a slower and uniform cool down. It would take more time to heat it up but if safety is a priority it's worth it.

Just a thought, comments more than welcome.

Joe

The H2SO4 is not the issue. The issue is trying to concentrate nitric acid (HNO3). Nitric acid decomposes from light or heat. Heating causes the acid to evolve several different nitrogen oxides weakening the acid as it concentrates. You can concentrate it quickly which will cause loss of acid or very slowly and retain the acid concentration but its really slow. As a matter of safety, a sand bath or oil bath is always recommended when evaporating with heat.

 

[Harold_V]

Place the beaker in a sand bath while boiling off excess H2o.

One of the buttons that triggers a negative response in me is the mention of "boil" when evaporation is the intended purpose. While it may not be an issue when evaporating sulfuric acid, the use of that term tends to create a bad habit which is then used when one discusses evaporation of values. For that reason, if you hope to remain on good terms with me, do NOT make reference to evaporation by using the term ***boil***. I get my shorts in a knot over that issue and become rather aggressive in setting the record straight, as I refuse to stand by and watch careless use of words undo the hard work we've done on this board. It is up to you to learn the acceptable language we use. You'll do that by reading instead of talking.

Harold

 

[joekbit]

Harold

Thanks for the notice

Joe

 

[necromancer]

great post, thanks to Lazersteve, GSP, Palladium, Harold_V, Butcher & Geo (everyone else)
well worth the bump. cold nitric method sounds like the way to go for me.

Lazersteve's Reaction:

-Bring 100 mL of Distilled Water in a 500 mL pyrex beaker to 100 C
-Add the Nitre of your choice (202 gm K / 170 gm Na)
-Stir until Nitre is completely dissolved, let cool below boiling
-SLOWLY add 56 mL conc (96%+) Sulfuric Acid to Hot Nitre solution while stirring, DON'T allow the solution to boil!
-Allow solution to cool to room temp (DO NOT SKIP - VESSEL WILL SHATTER IF PUT ON ICE WHILE HOT!!!)
-When vessel reaches room temp (25 °C) put the vessel in the freezer or on a salt water ice bath
-Let stand until temperature of mixture reaches -5 °C
-Let stand at -5 °C until all precipitate settles
-Pour the COLD solution off into glass container with tightly sealed lid DO NOT POUR OFF ANY OF THE SALT IN THE BOTTOM!!!
-Makes ~160 mL ~50% HNO3

 

[72chevel]

Bought a 5 gallon of battery acid today at Napa it was 32.99 and O'Reilly's had the same for 24.99

 

[rickbb]

Bought a 5 gallon of battery acid today at Napa it was 32.99 and O'Reilly's had the same for 24.99

I get a 1 1/2 gallon box at O'Reilly's for $8. Lasts me a long time.

 

[Kubik_Rubik]

I am going to try the cold nitric method and before I start, I would like to ask a few questions:
Can the solution be cooled to a temperature lower than -5 ° C, for example -10 ° C, or will it cause problems? And how long does it take to precipitate and settle Na2SO4?
I assume that this not perfectly pure HNO3 is not suitable for dissolving silver due to the reaction: Na2SO4 + AgNO3 = NaNO3 + Ag2SO4? But can it be used to prepare AR and dissolve palladium without problems?
thank you for answer

 

[Dragnfly1]

I just want to point out some misinformation at the end of this thread. It states that after adding your nitrate salt, you should let the solution cool down below boiling. Well needless to say I tried this and think I may have failed. So I went back to the beginning of the thread to read and noticed that lazersteve states that you should let the nitrate solution cool to room temp before adding the sulfuric acid. Well I just don't want anyone to make the same mistake as me and waste your time and materials by not allowing the nitrate solution to cool down enough before adding the sulfuric acid. Which I think allowed the synthesis to boil when I added the sulfuric acid to the nitrate solution.

Thanks for a great forum, I really appreciate all the information, although it's sometimes a hassle trying to figure out what's right and what's wrong. Lol

have a great day.

 

[Acidrain]

Chris,

Nothing appears wrong with yours a first glance, except in mine I'm not leaving any Hydrogen behind as follows:

H2SO4 + 2 NaNO3 --> Na2SO4 + 2HNO3

The big difference in my recipe is the solubility of the sodium sulfate salt (as opposed to sodium hydrogen sulfate you produce) and the fact that my equation yields twice the nitric acid at a higher temperature ( no dry ice, just salted ice ).

I've run the numbers like you did and ended up with about 160 mL of 50% nitric (give or take a few percent) for a single mole of 96% sulfuric and using 100mL H2O to dissolve the nitre.

I won't bore everyone with the math, but here's my summary (PM me to see all the factors I used to derive this reaction):

Reaction:

-Bring 100 mL of Distilled Water in a 500 mL pyrex beaker to 100 C
-Add the Nitre of your choice (202 gm K / 170 gm Na)
-Stir until Nitre is completely dissolved, let cool below boiling
-SLOWLY add 56 mL conc (96%+) Sulfuric Acid to Hot Nitre solution while stirring, DON'T allow the solution to boil!
-Allow solution to cool to room temp (DO NOT SKIP - VESSEL WILL SHATTER IF PUT ON ICE WHILE HOT!!!)
-When vessel reaches room temp (25 °C) put the vessel in the freezer or on a salt water ice bath
-Let stand until temperature of mixture reaches -5 °C
-Let stand at -5 °C until all precipitate settles
-Pour the COLD solution off into glass container with tightly sealed lid DO NOT POUR OFF ANY OF THE SALT IN THE BOTTOM!!!
-Makes ~160 mL ~50% HNO3

Steve

I performed this synthesis last night with absolutely perfect results.
100ml Distilled water
170g 99.9% Sodium Nitrate
56ml 98% concentrated Sulphuric acid

I did indeed yeild exactly 160ml nitric acid which immediately goes to work on copper
One thing I noted, as it was late and I was tired so I stoppered my boiling flask and let the solution sit overnight, is that upon reaching ambient temperature crystal formation started in the bottom of the flask and when I got up this morning there was a thick crystalline mass that formed on the bottom and a half inch up the sides. Very beautiful actually! After work today I put the flask in a salted ice bath for a few hours but the crystalline mass did not seem to grow much if at all.
I had expected the sodium sulfate to form small crystals and "precipitate" which did not happen.