werdy666
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Location: NSW, Australia
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Planning 1st attempt of NitroCellulose
Hi,
I have been researching and am planning an attempt to turn some cotton balls into NC.
My plan is
70ml Sulfuric Acid (98%)
30ml Nitric Acid (70%)
Cotton Balls ( Approx 3-5 grams)
Sodium Bicarbonate + water
Icebath
Cool bioth acids to 0c pre mix in ice bath
Mix the 2 acids in together.
Ice bath until 0c
place cotton balls one at a time into mixture, covering them in the acids. Still in ice bath
Stirring them around to get the acid all throughout the cotton balls.
leave them in there for an unknown time.
Rinse them with water a few times thoroughly and place them into some Sodium Bicarbonate to make sure they are acid free. Until they stop bubbling
after place with into some fresh sodium bicarbonate.
Letting them air dry for however long it takes.
I have been doing research and I have heard the soaking time to be anywhere from 2 minutes to 24 hours. and a few in between times as well. How long
should I leave them in the acid bath for??
Also one thing I have only read a couple of times is that you can reuse the acid again?? Is this possible? How much potency does the acid lose after
the first bath for a 2nd run with cotton balls???
Could someone direct me to an article on how Nitro Cellulose was made back in the day?? Like this but just on a much larger scale? or something
different??
And all this is done outside of course. I've seen mine HNO3 make that nasty orange gas outside in the past!
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Rainwater
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Face shield, rubber gloves, tested cotton.
And an area capable of safely containing an accident
And a stick to dump everything into an ice water bath
A lot of cotton balls are a cotton polyester blend.
And can catch fire/explode/melt to mush.
Any contamination can result in explosive failure.
Check local laws and regulations
Time is temperature dependent, slowly mix reagents and cool
Try to keep below 40c
Test test test.
Data you want to collect for each cotton ball
Starting weight
Reaction temp
Reaction time
Ending weight
How easily does it turn to powder?
Amount of Ash after burn
For each ball keep the temperature the same and increase the time.
As a result, you will see the weight increase
There is a balance between increased weight and dissolving your cotton.
Leave it in there too long and it will ignite.
Let the reaction get too hot and it will dissolve the cotton which can not be cleaned easily
Too cold and the mixture freezes and the reaction stops.
Colder and longer has given me the best results. 0c for 24 hours
The topic is well covered on this forum
[Edited on 10-1-2023 by Rainwater]
"You can't do that" - challenge accepted
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woelen
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I did the experiment several years ago, on a small scale and repeated it a few times. I noticed that the experiment is not critical at all, it is easy
to make a nice batch. You can reuse the acid one time, maybe two times, after a succesful batch.
If you follow the directions on my web page (see link below), then you almost certainly will succeed and as the experiment is at a very small scale,
nasty accidents hardly can occur.
https://woelen.homescience.net/science/chem/exps/nitrocotton...
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B(a)P
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There is a book in the SM library called the Chemistry of Powder and Explosives by Davis, which contains all the information you could ever want on
nitrocellulose. If you can get your hands on Chemistry and Technology of Explosives by Urbanski, even better.
A good first step is to boil your cotton in a 2% NaOH solution to help remove and impurities, then rinse and thoroughly dry.
Assuming you want to fully nitrate each cellulose, you will be adding three nitro groups per cellulose molecule.
So
3 HNO3 + C6H7(OH)3O2 → C6H7(ONO2)3O2 +
3 H2O
Use this to work out how much cellulose you can nitrate with a given amount of nitric acid. Noting that you need an excess of nitric acid to make the
above reaction occur. If you do not have a sufficient excess you will produce mono and bi nitro compounds. Urbanski has some good charts on the
percentage N that will be achieved for your nitrocellulose based on the composition of your nitration mix.
If you keep your temperatures as you describe you will not produce noticeable gas, but you are correct, this is best done outdoors or in a hood.
In terms of nitration time I have always gone with greater than 10 hours but less than 24 as is convenient, with good results. After the addition of
the cellulose you can allow the mix to slowly come up to room temperature either by removing it from the ice bath or just leaving it in there, but not
replenishing the ice.
You will also get a good result using sulfuric acid and a nitrate salt as your nitration mix, which is typically done to preserve your stock of nitric
acid.
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