PowerLabs Nitrocellulose Synthesis

INTRODUCTION:

Also known as "Cellulose
Nitrate", "Collodion Wool", "Soluble Gun Cotton", "Iodion Cotton", "Pyroxylin",
"Colloxylin" "Xyloidin", "Celloidin" "Parlodion", nitrocellulose is a product
that has found many uses on everyday life. It is a white, yellow or transparent
plastic, which can be anywhere from brittle to flexible. Nitrocellulose (mainly
C6H7N3O11)is used to make anything
from Smokeless Gun Powder (also called Triple Base, due to the addition of
nitroglycerine, nitroguanidine flash suppressor and burn rate catalysts), Double
Base (DB) solid rocket propellants (with 30 - 50% nitroglycerine added to result
in a perfect oxygen balance), to waterproof fuses in pyrotechnics, inks,
adhesives, varnishes, resins, lacquer coatings, embedding sections in
microscopy, photography, electro techniques, galvanoplasty, and even certain
plastics, such as what is used in ping-pong balls. It can have properties
ranging from a strong, resistant plastic to an unstable class B (highly
flammable, explosive when confined) explosive material, all determined by the
nitrogen content...
Here the procedure for making nitrocellulose are
outlined with the sole intent of scientific information. Although it is one of
the safest nitration procedures (there have been no reported cases (at least
that I am aware off) of incidents occurring during manufacture), and the
cellulose nitrate produced here is of a lower nitrogen content (the plastic
tetranitrate, as opposed to the explosive hexanitrate), the products do require
expert handling, and even though it does not constitute in a very big explosion
hazard, the procedure requires the handling of concentrated Sulphuric and Nitric
acids, as well as highly flammable Acetone, which make it very hazardous for
anyone unskilled with chemistry to attempt. Once again I discourage anyone to
attempt these procedures, and if you choose to do so you are doing it at your
own risk.

Reactants:

Materials:

98% Concentrated
Sulphuric Acid (H2So4(l))

Two clean glass
beakers

70% Concentrated Nitric
Acid (HNO3(aq))

Pipette

Pure Cotton (90%
Cellulose, C6H10O5(s))

Stirring
Rod

Acetone
((CH3)2CO(l))

Distilled Water
(l)

Sodium Bicarbonate
(NaHCO3(s))

For trinitrate the formula is
as follows: C6H7O(OH)3O + 3 OHNO2
--> C6H7(ONO2)3O +
3H2O

Here all the materials and
reactants needed for the synthesis of nitrocellulose can be seen: From the back
row to the front, from left to right:

100mL bottle of 98%Conc.
H2So4, 100mL bottle of 70% Conc. HNO3, 1L of
Distilled Water, 100mL of Acetone.
10mL Glass pipette
0.5g
cotton pad, 2X 150mL Pyrex glass beakers
Glass stirring rod.

For this procedure 5ml of 50
- 50% (by vol.) nitrating mixture was prepared, as seen below, and to it the .5g
cotton pad was added. The cotton was allowed to nitrate for five minutes at room
temperature, while stirring.

The cotton was than washed once in
saturated sodium bicarbonate solution and 2 times in distilled water, until the
leftover water tested neutral. It was than allowed to thoroughly dry and
dissolved in acetone.

The acetone was than allowed to vaporize
until a concentrated syrup-like nitrocellulose lacquer formed. A small bit of
un-nitrated cotton was than removed, and the rest of the acetone was allowed to
dry.

Below a dry cylinder of nitrocellulose
can be seen. Notice how it has taken the shape of the beaker and how it formed
thin sheets of NC that were smeared on the sides of the beaker: those thin
sheets are a material very similar to what is used in guitar and other
resistant, high gloss coatings... Next to it is a picture of the cellulose
burning. It burns all at once, with a fast bright flame and a characteristic
"phomp!" noise as the gas expands. The yellow color is due to carbon in the NC
molecule. Notice how it does not produce any smoke. There is, however some
residue left, proof that this plastic is the product of incomplete
nitration.

CELLULOSE
HEXANITRATE:

(For curiosity purposes only, POWERLABS
outlines the method used for making rocket-fuel and double base powder grade
nitrocellulose.)
The procedure is very similar to the one outlined
above, except it uses a slightly different nitrating mixture. The proportions
are now 35% / 65% (by volume) for HNO3 / H2SO4,
assuming that the acid concentrations used were the same as the ones used above.
5 parts of acid are used for every part of dry cellulose (per weight). An
alternate nitrating mix is made by adding 1gram of finely powdered Potassium or
Sodium Nitrate (KNO3/NaNo3) for every 3.325g (3.819ml) of cold
concentrated Sulphuric Acid (H2SO4), and than add cotton
to this nitrating mixture when the temperature has stabilized. I don't use this
particular procedure because it is hazardous (there is a lot of heat involved in
the formation of nitric acid by removal of nitrate from the potassium ion) and
can cause sputtering as well as releasing toxic fumes. Plus resultant mixture is
not only nitric and sulphuric acids, but also includes potassium or sodium
sulphate, which will have a negative effect on the quality of the final
product.
Complete nitration takes about 10 minutes at room temperature.
On a small scale not enough heat is evolved to justify an ice bath, which would
only slow the process down. The mixture with a greater sulphuric acid content is
able to impart more nitrate ions to the cellulose, causing it to have a much
higher nitrate (nitrogen and oxygen) content. The procedure is still reasonably
safe to perform from a stability point of view (meaning that it is virtually
impossible for the nitrocellulose to form upon formation), but now the resultant
product (when dry)  burns a lot faster, hotter, and releases much more
energy than the trinitrate above. It is, in fact, one of the most energetic
deflagrants known, capable of DDT (Deflagration - Detonation Transition) with
123-147% the explosive strength of TNT when detonated at 7300 meters per second
(Nitrocellulose (13.35% N) max density 1.2g/cc).
NOTE: It is very
important to thoroughly neutralize the nitrocellulose by boiling it in
NaHCO3  and in distilled water several times until it tests
neutral. It is also recommendable to add 0.5-1% of Urea or diphenylamine in fine
powder form to neutralize any remaining nitrogen oxides that could become acidic
in moisture and causing accidental ignition of the product.
This
product can be stored safely under water or dissolved in acetone (NC
Lacquer).
Now I must say the warning. The nitrocellulose produced by
this method is EXPLOSIVE and can deflagrate or even detonate violently on shock,
friction, or spark when dry. These procedures are not to be attempted, and are
outlined here only for informational purposes.

Click on the frame sequence above to watch a
short (146KB) .mpg video of a 3cm (1.2") 1gram fluffy nitrocellulose ball being
deflagrated by flame. The ball was merely sitting on top of a stand, as *ANY*
confinement, even it being inside an open jar, would have resulted in an
explosion. The heat produced by this burn is so fantastic that it could be felt
over a two meters away (you should never look directly at large deflagrations as
the light emitted can cause damage to the retina). Despite the fact that the
camera was positioned 2 meters from the flame, and that all adjustments were
made to avoid the light flooding effect, the camera still couldn't handle the
flash that was made. The sound of the flame is a low pitched thump, indicating a
large, subsonic air displacement. Of course, due to file size limitations a lot
of the original sound and video quality were lost.
Finally, you might have seen (or heard off) a
product called "Flash paper" its often used in magic tricks: A square piece of
normal (white) paper that burns quickly in a flash without making any smoke or
leaving any residue. All it is is a piece of nitrated paper, as per the above
method. The picture here shows a piece of nitrated toilet paper (around the
metal stand) burning.

Note: Runaway nitration for
nitrocellulose occurs at 70oC. Never allow it to go above that
temperature while in a nitrating mixture. Never attempt to nitrate large batches
at once as the increased heat output will invariably result in
runaway.

[ Home ] [ Up ] [ Next ]

Comments? Questions? Don't hesitate to
e-mail me!

People have visited
this page since 27/04/00

Last update 30/01/04

Copyright © 2000-2002 by Sam Barros. All rights
reserved.
Removing any material from this site for display
without consent from its author consists in an infringement of
international copyright laws and can result in fines up to $50000 per
infringement, plus legal costs. So ASK ME before you remove anything from
here.