An Improvement in the Treatment of Nitro-cellulose, for the Manufacture of Explosives and other Products.
Year: 1898

page_text: Date of Application, 3rd Mar.,
1898
Complete Specification Left, 24th Aug., 1898-Accepted, 25th Feb., 1899
An Improvement in the Treatment of Nitro-cellulose, for the
Manufacture of Explosives and other Products.
We, ALFRED LUCK, of Brentcote, Dartford, Kent, Chemist, and CHARLES FREDERICK
CROSS, of 4, New Court, London, W.C., Chemist, do hereby declare the nature of this
invention to be as follows :—
Nitro-cellulose, as it is usually manufactured retains a fibrous structure which
occasions considerable difficulties in the subsequent treatment. Our invention relates
to means of avoiding these difficulties by reducing the nitro-cellulose at once to a
structureless condition without mechanical treatment. For this purpose we subject
nitro-cellulose either in the mass or in a granulated condition to the action of acetone
or other known solvent diluted with about one fourth of its volume of water.
This rapidly completely destroys the fibrous condition of the nitro-cellulose
and at the same time frees it from certain impurities which remain dissolved in
the liquid. The resulting product whether fine powder or structureless granules, is
then washed and dried and is at once ready for use as an explosive or for
treatment to obtain other products such as collodion, celluloid or the like, by the
known processes.
TL 1000
ABEL & IMRAY,
Agents for the Applicants.
An Improvement in the Treatment of Nitro-cellulose, for the
Manufacture of Explosives and other Products.
We, ALFRED LUCK, of Brentcote, Dartford, Kent, Chemist, and CHARLES FREDERICK
CROSS, of 4, New Court, London, W.C., Chemist, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
Nitro-cellulose, as it is usually manufactured, retains a fibrous structure which
occasions considerable difficulties in the subsequent treatment. Our invention
relates to means of avoiding these difficulties by reducing the nitro-cellulose at once
to a structureless condition without mechanical treatment. For this purpose, we
subject nitro-cellulose either in the mass or in a granulated condition to the action
of solvents such as acetone, acetic ether, pyridine, nitrobenzene, and the like, diluted
with a proportion of inert liquid; in the case of acetone or other solvent miscible with
water, we use preferably water as the diluent. When the solvent is not miscible with
water, as for instance nitrobenzene, it may be diluted with alcohol.

page_text: Such liquids rapidly and completely destroy the fibrous condition of the nitro-
cellulose, and, at the same time, it is freed from certain impurities which remain
dissolved in the liquid even after further dilution.
The case of acetone may be taken as typical, and we shall therefore describe the
process as carried out with this solvent. A cellulose nitrate of say 13 per cent.
nitrogen (taken not necessarily in a dry condition) is placed in a suitable vessel and
a diluted acetone, that is acetone diluted with water in the proportion of about 92
parts acetone to 8 parts water by volume, is poured upon the fibrous nitrate, in
quantity sufficient to cover it. The change of physical condition rapidly ensues,
the swelling of the fibre being followed by disintegration so that, on slight agitation,
the last remnants of the original fibrous structure are destroyed.
This effect is attended by a certain limited solvent action upon the fibrous nitrates
whereby certain constituents are taken up in solution and in fact in a permanently
soluble formn. On diluting with water any cellulose nitrates which may have been
dissolved are precipitated; but there remains in solution a group of constituents of
strongly acid character which it is desirable to eliminate. The insoluble nitrates are
therefore separated from the solution containing these by-products by filtering and
washing first with dilute acetone then with water to recover the acetone as completely
as possible. The washed product is then dried and is found to possess the character-
istics of stability required for working up into the special forms required in
commerce. Thus, besides effecting the physical change from the fibrous to the
structureless form, the process chemically purifies the product.
For certain purposes the fibrous nitrate may, in the first place, be granulated in
the wet state the granules being then treated as above described rendering them
individually more or less structureless and coherent without any tendency to
agglomerate into masses. On further dilution of the acetone and washing, the
granules acquire density and hardness and, on being dried, form a free granulated
powder. The product is also chemically "stable." The simultaneous changes in
form and composition furnish a product which may be directly worked up for
smokeless powders suitable for the class of explosives known as sporting powders.
Instead of entirely removing the fibrous character of the product, we can so treat
nitrocellulose that it becomes a fine fibrous powder. For this purpose, we prefer to
employ a mixture of acetone and alcohol, for instance in equal proportions by volume.
The product is covered with this mixed solution and, on then adding water, the
material is reduced to the condition of an extremely fine fibrous powder.
The removal of by-products causing instability may be effected as a separate
treatment independently of disintegration, by treating the fibrous nitrate with a
more dilute acetone, such as equal parts by volume of acetone and water.
From any of the treatments above described there is a dilute acetone residue from
which the acetone may be recovered by distillation at a low temperature.
The acid products remaining in solution have the property of forming insoluble
lead compounds, and may be precipitated by the addition of a solution of lead
acetate. The lead salts thus obtained contain 50 to 630 per cent. of Pb. O and
3 to 4 per cent. of nitric nitrogen. They are explosive and may be used in
fireworks.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
The treatment of nitrocellulose with a diluted solvent so as to render it more or
less structureless and to clear it from impurities, substantially as described.
Dated this 24th day of August 1898.
ABEL & IMRAY,
Agents for the Applicants.