Sciencemadness Discussion Board

Nitrocellulose help

xonu - 22-1-2021 at 09:18

Hello!
I am having a lot of trouble making NC from ~95% Sulfuric Acid (boiled down bat) and 63% Nitric Acid. The proportions are 3:1 and the nitration time is 15 minutes
The synthesis has worked exactly once for me, and another problem is that my cotton falls apart in the nitration mixture and turns into a slimy substance. The end product barely burns and just melts on a fire.
What am I doing wrong?

[Edited on 22-1-2021 by xonu]

Alkoholvergiftung - 22-1-2021 at 09:26

Concentration of Nitric acid should above 69%. More Sulfuric acid more time to nitrate. Fast nitration 1:1 slow 3:1. Temperature bellow 30C for collodium you can go above 40 and nitration reaction is faster.

greenlight - 22-1-2021 at 10:11

It shouldn't fall apart and go slimy. Make sure it's 100% cotton balls or whatever form it is that your using. Stuff from the pharmacy is usually pure.

Leave in the nitration bath for a lot longer. There's three hydroxy groups on a cellulose molecule that can take an NO2. Although it is quite hard to get the trinitrate for a 13% nitrogen content.


[Edited on 22-1-2021 by greenlight]

B(a)P - 22-1-2021 at 12:14

If your cotton is pure it might be that the sulfuric acid is decomposing the cotton, what temperature are you getting up to?
If you don't have a more concentrated nitric acid you could consider using a nitrate salt, that will give you a stronger nitrating solution than you describe above.

xonu - 24-1-2021 at 07:20

Hmmm, thanks for everyone's help, I think my problems are insufficient cooling and low nitric acid concentration, my beaker was getting hot to the touch when stirring the mixture, so maybe that was what caused the cotton to decompose.

DBX Labs - 24-1-2021 at 08:39

The nitration mixture should always be cooled to below 10C before any cellulose is added. External cooling while the esterification takes place is generally required as well.