How to get rid of sulfuric acid?

[G4piro]

Some time ago I reacted nitric acid with sodium hydroxide to get rid of the acid and as a byproduct to get sodium nitrate (NaNO₃) which can be used as an oxidizer.
Now I also want to get rid of the sulfuric acid (H₂SO₄ 96% 400ml), Does anyone have an idea for a chemical reaction that will get rid of the sulfuric acid and create another useful substance?

 

 

In the video, a comparison of BP with different oxidizers. The BP with NaNO₃ used to create a visco fuse that burned slowly.

Edited October 10, 2023 by G4piro

[cmjlab]

You could use it with potassium nitrate to make some nitrocellulose (assuming the other 4% of the 96% is water).

 

Calcium Carbonate and H2S04 = gypsum.

 

Or the sodium carbonate / bicarbonate route (saturated solution in a large container, to which you add the acid - not the other way around).

[Richtee]

You could use it with potassium nitrate to make some nitrocellulose (assuming the other 4% of the 96% is water).

 

 

Huh - could you explain this process?

[cmjlab]

The nitrate takes the place of nitric acid, and sulfuric acid serves as both desiccator and reactant to disassociate nitrate into nitric acid and the corresponding sulfate salt (depending on the nitrate used).

 

Potassium nitrate is preferable as it can be dried and is not hygroscopic enough to absorb water from the air in the short amount of time between drying it and reacting it with sulfuric acid.

 

The less water introduced beforehand, the better the nitration process proceeds, since water is also given up during the nitration process, and requires the concentrated sulfuric acid to remove it and allow nitration to proceed to completion.

 

I believe the process resembles H2S04 + KN03 -> HN03 + K2S04, I'm sure there is some water given up from the reaction too.

 

There's several tutorials online about it. I don't think you'd achieve super high nitration, but it's certainly serviceable nitrocellulose dissolvable completely in acetone (which implies a certain min nitration level). I still prefer the nitric acid / sulfuric acid route, it's simpler / cleaner / better quality in my opinion.

 

I wouldn't recommend anyone to try making it without some chemistry knowledge - If anyone reads this and decides to try it, make sure you understand the toxic fumes that can kill you hours after exposure, potential run-away nitration risks, PPE, etc.

Edited October 10, 2023 by cmjlab

[cmjlab]

I figured since I described half the process, i'd also address the other danger with homemade guncotton / nitrocellulose.

 

Cleaning the nitrocellulose is an equally important step, but twice as frustrating. Just washing it with fresh water for 3 straight hours doesn't seem to neutralize all the acid. If you don't neutralize all the acid (and stabilize it - addressed in next para), then the remaining nitric acid will accelerate the decomposition into nitrogen dioxide (NO2) - or that brown poisonous gas that can kill you. You'll be able to easily tell when it happens because the nitrocellulose will turn yellowish with brown spots, and will have an eye watering acrid smell.

 

The only way I've figured out to seemingly neutralize the nitric acid is to chop / shred the nitrocellulose fibers apart under water or while wet, and wash several more times with fresh water each time. I even tried to turn it into powder once by dissolving in acetone and crashing the nitrocellulose out of solution with water or alcohol (story for another time - it worked okay).

 

To stabilize, there are a few ways. Urea is easily accessible and is the method I use. I just make a 5% solution (W/W) and wash the nitrocellulose, then rinse one last time with fresh water, and layout in a warm dry area away from anything that could cause it to ignite (like shiny metals that reflect the sun, glass containers, etc).

 

Once it's dry I, I store it wet in 90% Isopropyl Alcohol. Keeps it less likely to heat up and decompose, harder for it to catch fire accidentally, yet dries quickly in front of a fan when needed.

 

Lastly, don't store it in a ziplock container or other airtight container. That apparently accelerates the decomposition. I've heard some people store it in the freezer that way successfully, but I prefer to keep it wet until needed, them dissolve it in acetone.

Edited October 11, 2023 by cmjlab

[Richtee]

Thanks. More of a curiosity on my part. I have tried a few methods. Had a run-away the other day...Ugh. That was with nitric/sulfuric. Not chilled was the deal I figger.

 

Honestly, I have access to nitro powders- so this, again, is more curiosity.

[Arthur]

NC synthesis is prone to runaway reactions all of which create risks and reduce yields. It's probably best bought. Even in storage pure NC decomposes autocatalytically, commercial NC contains stabilisers to reduce this.

 

As for conc sulphuric, find a use for it or trade it with someone local for something more useful to you. Strong chemicals will steadily become harder to buy by amateur users.

[cmjlab]

Thanks. More of a curiosity on my part. I have tried a few methods. Had a run-away the other day...Ugh. That was with nitric/sulfuric. Not chilled was the deal I figger.

 

Honestly, I have access to nitro powders- so this, again, is more curiosity.

I had this happen on the first or second shot at making NC. Same issue, I didn't have it chilled because a chemistry manual I read didn't mention that it was necessary to control the temp. No issues after that, I just used salt / ice bath to control it.

 

I prefer the gun cotton because it's less expensive to make the nitric acid, and use cotton - sulfuric acid can be acquired cheaply and purified easily. However, I'm in the same boat as you, I've started using smokeless powder due to ease of storage and less work overall!

[cmjlab]

Thanks. More of a curiosity on my part. I have tried a few methods. Had a run-away the other day...Ugh. That was with nitric/sulfuric. Not chilled was the deal I figger.

 

Honestly, I have access to nitro powders- so this, again, is more curiosity.

I had this happen on the first or second shot at making NC. Same issue, I didn't have it chilled because a chemistry manual I read didn't mention that it was necessary to control the temp. No issues after that, I just used salt / ice bath to control it.

 

I prefer the gun cotton because it's less expensive to make the nitric acid, and use cotton - sulfuric acid can be acquired cheaply and purified easily. However, I'm in the same boat as you, I've started using smokeless powder due to ease of storage and less work overall!

[cmjlab]

NC synthesis is prone to runaway reactions all of which create risks and reduce yields. It's probably best bought. Even in storage pure NC decomposes autocatalytically, commercial NC contains stabilisers to reduce this.

 

As for conc sulphuric, find a use for it or trade it with someone local for something more useful to you. Strong chemicals will steadily become harder to buy by amateur users.

Arthur I agree that from a simplicity, ease of use/storage, and longevity standpoint that commercial NC in smokeless propellant is a pretty good alternative.

 

However, I don't think most of our European counterparts can easily purchase smokeless propellant or NC linters. Even here in the U.S., most of the commercial vendors require a license, proof of laboratory use, or non-residential address to sell NC. A couple pyro supply sites occasionally carry pure NC, though I don't believe it's high nitrogen content, or offer some NC lacquer alternative which is full of other ingredients and not good for much beyond binding of stars where color purity is not a major concern. I also believe from a cost analysis standpoint, that even if you have to buy glassware to make the nitric acid and purify sulfuric acid, that after the 3rd or 4th batch of pure / high nitration level tri-nitrocellulose, you will have made your money back. Plus, you have the ability to create up to ~70/75% Nitric Acid (red / yellow fuming nitric acid) to make other useful pyro compounds.

 

Where we do agree is that there is inherent risk which each person has to assess for themselves based on background knowledge, understanding of the reactants and potential risk, and residual risks after mitigating as much as possible. (I've seen farmers explosive manual floating around here or another pyro forum which demonstrates that people were trusted to learn / employ methods to accomplish work / tasks in the past, but thanks to government overreach and deciding we can't be trusted with such things, are viewed as taboo now - alm that to say, I think a person can learn new skills if they have the desire / drive / a little common sense).

 

In addition to the safety warnings / measures in my earlier post (cleaning, stabilizing the NC, no sealed containers, refrigeration of final product, etc.) these are other mitigating factors that make it "reasonably " possible to make your own NC.

 

Ice bath throughout the process (beginning when you combine the acid & nitrate OR H2S04 & HNO3, up to breakdown and neutralization of the leftover acids) greatly reduces this concern.

 

Numerous rinses with fresh water, shredding the NC to ensure remove acids trapped inside the fibers, and stabilization with urea or other stabilizer, greatly prolongs NC storage.

 

Most important of all, limiting your NC batch size reduces likelihood of runaway reaction, decomposition or spontaneous combustion due to failure to remove / neutralize acids, and damage control if all else fails and you have an incident by limiting the amount of NC to cause injury / damage.

 

Lastly, neutralization of potential remaining acids with sodium carbonate / bi-carbonate or other alkali salt can result in residue remaining in the NC to counter potential acid remaining or formed from normal decomposition.

 

I've never made more than a 100g batch as that is a lot of cotton balls cotton linters.

 

That ends my rant.... :-)

Edited October 11, 2023 by cmjlab

[Arthur]

NC comes in different nitration levels. IIRC 13% nitrogen is the fastest ever routinely made -it's explosive/burns very fast, nitrations down to 10% N give highly flammable compositions but with much lower burn rate, ultimately NC guitar lacquer is flammable but can't be made to explode. Each type has it's own sales restrictions.

 

A lacquered guitar has different storage requirements from shotgun powder!

[G4piro]

So, I decided to react with sodium hydroxide because of the ease of the reaction and the materials I had. And also, because sodium sulfate is used as a desiccant for organic solutions which can be useful for me.

[Pyrogeezer]

 

The company that does our tolling for Pyro grade Nitrocellulose Lacquer purchases the raw fiber from a large manufacturer in the ROC. I am not aware of anyone in the US that still manufactures NC on the level that we require to produce our lacquer. The product that we use comes in heavy gauge plastic bags inside of 50 gallon size fiber drums. It is dampened and stabilized with 30% IPA. We have never stored it longer than 6 to 8 months, we process it into lacquer soon after purchase. It comes in several grades and forms. Nitrogen content, from 10% to 12%+, in fiber, flake , chip form and also in many different RS viscosity ratings referring to the type of finished lacquer you are producing. The Viscosity has nothing to do with the actual nitro fiber itself but only to the finished lacquer. The Ion concentration  of the material upon arrival is normally between 7.1 and 7.3. Over 6 to 8 months there is little or no change. Important to note that when making lacquer the use of NC fiber wetted with water is a no-no. it needs to be dried completely 100% or it will produce a hazy or foggy finished lacquer product.