Stabilizing Nitrocellulose

[JacobS]

Okay, so I have set up a small lab in my backyard with the express intent of making nitrocellulose for use in model rockets. I already know the basic principle of how to make it, but I don't have as much ready access to Sulfuric as I would like. So, I'm wondering for safeties (and my wallets) sake if there is a way to stop run-away nitrification caused by only using Nitric Acid, such as simply neutralizing the guncotton. Should be that possible (and I'm fairly sure it is) what should I use? I know Lye is a popular choice, but I'm wondering if i could use something like bleach or perhaps even baking soda for the same purpose. For the record, I'm planning to make VERY small quantities of this, especially at first, and I don't plan on storing the nitrocellulose for any period of time. Just a guy that likes to understand things and put that understanding to use on something I'm passionate (such as model rocketry). Any help and suggestions are appreciated, I'm not stupid enough to attempt something like this without the wisdom of the better educated.

 

-Jacob

[Suxamethonium]

My first question is "why is over nitration bad?" After that my second question is "So, if what you propose doesn't work then you will still get excessive nitration. Are you still prepared to carry out said experiment knowing that risk?" My third question is then "Ok, so how are you going to know when it is nitrated sufficiently?".

 

Also, just a tip- adding baking soda to concentrated nitric acid is not a wise idea.... its going to take a lot of baking soda and I would not be surprised if you ended up nitric acid all over your work-space (YAY! Volcano!!). Also unless you neutralise it quickly the added temperature will increase the rate of nitration.

[JacobS]

The problem with over nitration is it makes the nitrocellulose more sensitive (i believe.) and the baking soda would be added to the formed nitrocellulose after the material had been thoroughly rinsed. Also, if the nitration continued, I am reasonably sure I'm prepared. I will be doing a lot of theory and testing before attempting and larger-scale production, starting with making like 1-2 CM squares and making very few at a time. As far as i understand, over-nitrated nitrocellulose is reasonably safe as long as you don't plan to store it for very long, and also, i have access to stronger bases (such as NaOH) but Baking Soda is what was recommended.

[Suxamethonium]

...and the baking soda would be added to the formed nitrocellulose after the material had been thoroughly rinsed.

 

Sorry, it sounded like you were going to use it to neutralise the nitrating reagent- You could do just nitric acid, but this requires higher temps or activated reactants (as the electrophilic nitronium ion isn't produced in nitric alone). What you are doing is essentially an esterification just using an inorganic acid- so yes nitric will work, but nitric/sulfuric mixtures are better at it. Alternatively try sulfuric and potassium nitrate mixtures.

 

Also, neutralisation of the gun cotton after the reaction is mostly to make it non-corrosive- It does stop any continuing reaction, but such reactions wouldn't continue long anyway- especially if you washed even just with water.

 

From memory cotton has 3-4 nitratable positions per monomer. I'm assuming you only want mono-nitration. The best way to acheive this is just to keep the reaction mixture cold (on ice for 15mins or so).