Treatment of Wood for the Manufacture of Cellulose and other Products.
Year: 1894

page_text: Date of Application, th Jan., 1894
Complete Specification Left, 5th Oct., 1894-Accepted, 5th Jan., 1895
PROVISIONAL SPECIFICATION.
Treatment of Wood for the Manufacture of Cellulose and other
Products.
I, CHARLES FREDERICK CROSS, of 4 New Court Carey Street London, W.C.
Consulting Chemist, do hereby declare the nature of this invention to be as
follows:-
Many woods, especially white hard woods, may be subjected in the known
manner to the action of dilute nitric acid for the production of cellulose, but the
manufacture of cellulose in this way is too costly unless advantage is taken of other
products resulting from the treatment.
This invention relates to the treatment of wood_more especially, for obvious
reasons of economy, waste wood, with nitric acid and the further treatment of the
products resulting from that process in such a manner that the manufacture of
compounds of oxalic and acetic acids can be effected together with that of
cellulose palp simply and economically.
For this purpose, I subject 1 part of the wood in the form of fragments, chips,
turnings, shavings or the like to the action of 3 parts of nitric acid of about
10 per cent. strength and raise to a temperature of about 80° C., at or above which
temperature the material is maintained during the reaction by the heat generated
thereby. From the disintegrated mass or pulp produced by the reaction I squeeze
out the liquor containing the soluble by products leaving the pulp or cellulose which,
after washing, is ready for certain applications.
The pulp, however, contains in this state residues of the non-cellulose constituents
of the wood.
These are eliminated by washing or boiling with a weak solution of soda ash
followed by thorough washing, and, if a white product is required, by bleaching
in the usual way by treatment with a solution of bleaching powder. The cellulose
thus obtained may be nitrated with nitric acid of 1.5 specific gravity, directly without
the presence of sulphuric acid, and, when it is thus nitrated and washed, the dilute
nitric acid resulting from the washing can be utilised as the 10 per cent. acid for
treatment of the wood as described.
The liquor squeezed from the cellulose in the first instance, and that resulting
from the washing of the pulp with soda ash solution contain oxalic and acetic acids
formed during the action of the nitric acid on the wood and a further and consider-
able quantity of these acids, more especially the latter, is formed by treating the
liquors with caustic alkali in the manner about to be described. The liquors are
neutralised with a further quantity of soda ash if necessary and evaporated,
The thick
preferably by multiple effect, down to about 30-40 per cent. solution.
liquor thus produced is run into open vessels and a quantity of caustic soda is stirred
into it, about equal to the weight of the dissolved organic matter which it
contains, the whole being gradually heated in any convenient way to about
250-300° C.
By this process is obtained a brownish mass which is boiled with water, and from
the solution are crystallized out successively oxalate of soda, carbonate of soda and
acetate of soda.
For the caustic soda may be substituted the compound known as ferrite of soda
formed by heating to redness carbonate of soda with ferric oxide. In this case
iron oxide is recovered from the liquor and can be used for preparing fresh ferrite
of soda.

page_text: By the treatment above described a cellulose of great utility can be produced
economically, owing to the recovery of the acetates and oxalates from what might
be termed the waste liquor of the pulping process.
Dated this 8th day of January 1894.
ADEL & IMRAY,
Agents for the Applicant.
Treatment of Wood for the Manufacture of Cellulose and other
Products.
I, CHARLES FREDERICK CROss, of 4 New Court, Carey Street, London, W.C.
Consulting 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 :-
Many woods, especially white hard woods, may be subjected in the known manner
to the action of dilute nitric acid for the production of cellulose, but the manufacture
of cellulose in this way is too costly unless advantage is taken of other products
resulting from the treatment.
This invention relates to the treatment of wood more especially, for obvious
reasons of economy, waste wood, with nitric acid, and the further treatment of the
products resulting from that process in such a manner that the manufacture of
compounds of oxalic and acetic acids can be effected, together with that of the
cellulose pulp, simply and economically.
For this purpose, I subject one part of the wood in the form of fragments, chips,
turnings, shavings or the like, to the action of 3 parts of nitric acid of about
10 per cent. strength and raise to a temperature of about 80° C., at or above which
temperature the material is maintained during the reaction by the heat generated
thereby. From the disintegrated mass or pulp produced by the reaction squeeze
out the liquor containing the soluble by products leaving the pulp or cellulose which,
after washing, is ready for certain applications.
The pulp however contains in this state residues of the non-cellulose constituents
of the wood.
These are eliminated by washing or boiling with a weak solution of soda ash
followed by thorough washing, and, if a white product is required, by bleaching in
the usual way by treatment with a solution of bleaching powder. The cellulose
thus obtained may be nitrated with nitric acid of 15 specific gravity, directly without
the presence of sulphuric acid, and, when it is thus nitrated and washed, the dilute
nitric acid resulting from the washing can be utilised the 10 per cent. acid for
treatment of the wood as described.
The liquor squeezed from the cellulose in the first instance, and that resulting
from the washing of the pulp with soda ash solution contain oxalic and acetic acids
formed during the action of the nitric acid on the wood, and a further and
considerable quantity of these acids, more especially the latter, is formed by treating
the liquors with caustic alkali in the manner about to be described. The liquors
are neutralized, with a further quantity of soda ash if necessary, and evaporated,
preferably by multiple effect, down to about 30-40 per cent. solution. The thick
liquor thus produced is run into open vessels and a quantity of caustic soda is stirred
into it, about equal to the weight of the dissolved organic matter which it
contains, the whole being gradually heated in any convenient way to about
250-300° C.
By this process is obtained a brownish mass which is boiled with water, and from
the solution are crystallized out successively oxalate of soda, carbonate of soda and
acctate of coda.

page_text: For the caustic soda may be substituted the compound known as ferrite of soda
formed by heating to redness carbonate of soda with ferric oxide. In this case iron
oxide is recovered from the liquor and can be used for preparing fresh ferrite of
soda.
By the treatment above described a cellulose of great utility can be produced
economically, owing to the recovery of the acetates and oxalates from what might
be termed the waste liquor of the pulping process.
During the pulping operation gases are evolved, which require to be absorbed.
For this purpose I mix them with air and pass the mixture through a chamber
containing dry wood which it is intended to pulp. The wood absorbs the noxious
gases and is thus partially decomposed so that, in pulping, it is more readily acted
on by the nitric acid, and acid of less strength, such for instance as that of 7 per cent.
strength can consequently be employed. Among the gases given off during the
pulping, there is a considerable quantity of hydroxyanic acid which may be collected
by passing the gases through a chamber containing suitable absorbents of hydrocyanic
acid.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The manufacture of cellulose and other products by treating wood with nitric
acid so as to produce a cellulose pulp which is squeezed washed, and purified;
treating the resulting liquors with soda ash, concentrating, adding caustic soda or
ferrite of soda, heating, and separating by fractional successive crystallisations
oxalate, carbonate and acetate of soda, substantially as described.
Dated this 20th day of September 1894.
ABEL & IMRAY,
Agents for the Applicant.