Sciencemadness Discussion Board

Unclear recipe for Poudre B (nitrocellulose based gunpowder)

orchface - 26-10-2020 at 10:22

I saw this wiki page about synthesizing nitrocellulose and saw this page on Wikipedia about Poudre B, an early form of smokeless gunpowder.

In the article, it says
Quote:

Poudre B is made from 68.2% insoluble nitrocellulose, 29.8% soluble nitrocellulose gelatinized with ether and 2% paraffin

By "ether" I assume it refers to diethyl ether ((C2H5)2O). However, I am not sure what the difference between "soluble" and "insoluble" nitrocellulose is, since the article does not specify which solvents this applies to. Nitrocellulose (at any nitration level) is insoluble in water and soluble in acetone. At low nitration (less than ~13%), NC is soluble in ether/ethanol, but at high nitration it is not. Is this what the article is referring to, or is there another kind of nitrocellulose that is known as "insoluble"? Is this implying that the powder is 68.2% high nitrogen NC and 29.8% low nitrogen NC or am I missing something?

itsallgoodjames - 26-10-2020 at 10:54

Soluble nitrocellulose referrers to nitrocellulose with a nitrogen content under 12% by weight. Insoluble is above 12%. It's generally not referred to that anymore, due to confusion, but you will often see it in old books about pyrotechnics.

Fulmen - 26-10-2020 at 12:04

The classic solvent is ether/ethanol, which cannot dissolve 12% and above. I don't think acetone was available in industrial quantities before WWI.

Mateo_swe - 26-10-2020 at 12:36

Interesting, i have some nitrocellulose of unknown nitrogen content.
Its probably low% but it would be fun to test it.
The so called "classic solvent ether/ethanol", anybody know what ratios of diethyl ether/ethanol and is that absolute (waterfree) ethanol?

orchface - 26-10-2020 at 12:54

Quote: Originally posted by Mateo_swe  
Interesting, i have some nitrocellulose of unknown nitrogen content.
Its probably low% but it would be fun to test it.
The so called "classic solvent ether/ethanol", anybody know what ratios of diethyl ether/ethanol and is that absolute (waterfree) ethanol?


I was wondering the same thing. I scoured the internet for months and could not find a detailed instruction sheet on manufacturing Poudre B. Perhaps an old classified military secret that the French government hasn't bothered to declassify yet?

Also, I wonder if it is possible to use only the lowly nitrated cellulose for this powder (which requires chilled acids to make). I looked up the process for making highly nitrated cellulose and it involved boiling strong acids, which is extremely dangerous for an amateur experimenter like myself. I don't have proper safety equipment or training to handle boiling acids. Perhaps the final product would be less powerful if I didn't use the highly nitrated cellulose, but maybe that's a good thing.

[Edited on 26-10-2020 by orchface]

Mateo_swe - 26-10-2020 at 13:44

So the Sciencemadness wiki on synthesis of nitrocellulose (link in first post) will produce the low% nitrogen nitrocellulose?

So you want to make some Poudre B.
Be careful, i dont think its reliable and very well can go off without warning.
Isnt there more modern formulations that are a bit both better and safer?

Herr Haber - 26-10-2020 at 15:11

If you're aiming for Poudre B specifically and not just "some" nitrocellulose you have to start by chosing the same cellulose source(wood? lint?), clean it by the same methods (NaOH), etc. until you get to stabilization.

You should read all about NC based propellants in Urbanski, available in the library and decide if there's a method better suited to your needs and means.
Unless you are into historical reenactment of course :)

orchface - 26-10-2020 at 17:48

Quote: Originally posted by Herr Haber  
If you're aiming for Poudre B specifically and not just "some" nitrocellulose you have to start by chosing the same cellulose source(wood? lint?), clean it by the same methods (NaOH), etc. until you get to stabilization.

You should read all about NC based propellants in Urbanski, available in the library and decide if there's a method better suited to your needs and means.
Unless you are into historical reenactment of course :)


I will try to get my hands on a copy of Urbanski Chemistry & Technology of Explosives, that sounds like an awesome read :)

There is a guy on Youtube by the name Schel Sullivan whose method of preparing NC out of common store ingredients works very well. I use his method, with some small modifications to ensure that the NC is of highest possible quality. The finished product burns extremely quickly and leaves little to no residue.

Now I also read that NC decomposes over time. The Wikipedia article says "Nitrocellulose was found to gradually decompose, releasing nitric acid and further catalyzing the decomposition (eventually into a flammable powder)." Apparently the powder is much less effective than the original NC, but I am not exactly sure what the composition of this residual powder is. Would it be better then to use 100% of the gelatinized NC in diethyl ether, since this has been shown to have a much longer shelf life than raw NC? I believe diethyl ether is a common ingredient in engine starting fluid (along with heptane), so I presume one could distill out the ether and gelatinize the NC with it in order to make it last longer.

B(a)P - 26-10-2020 at 19:46

I have made NC many times and never found it to decompose.
In saying that I have never stored it for any length of time (<6 months).
I don't think decomposition is an issue unless you plan on storing it for years.
There is a good method with OTC reagents in the SM wiki - http://www.sciencemadness.org/smwiki/index.php/Synthesis_of_...
There is also a good reference in the library that covers nitrocellulose in great detail -
Davis 1943, The Chemistry of Powder and Explosives

Edit - Poudre B is covered in Davis 1943

[Edited on 27-10-2020 by B(a)P]

Herr Haber - 27-10-2020 at 10:54

Quote: Originally posted by orchface  

I will try to get my hands on a copy of Urbanski Chemistry & Technology of Explosives, that sounds like an awesome read :)



Get all of them and browse the index.
If memory serves, nitric esthers are in one tome and the propellants using them in another.