Researches on Cellulose | Page 9

celluloses, other than the
normal type.
Conclusions.--The subjoined table gives the mean numerical results for

yield of end-product or 'cellulose' by the various methods. In the case
of the 'celluloses' the results are those of the further action of the
several processes on the end-product of a previous process.
| Methods | F. Schulze | Weende | Lange | Gabriel | Cross | | | | | and
Bevan --------------------------------------------------------------------------
Wood cellulose | 98.51 | 91.52 | 48.22 | 55.93 | -- Filter paper cellulose
| 99.62 | 95.63 | 78.17 | 79.77 | -- Swedish filter paper | 96.58 | -- |
84.76 | -- | -- Ordinary filter paper | 98.17 | 93.39 | 86.58 | -- | --
Cotton ('wool') | 98.38 | 89.98 | 63.96 | 67.88 | -- Jute | -- | -- | 57.93 |
71.64 | 75.27 Purified wood | -- | -- |{49.27 | -- | -- | | |{46.56 | | Raw
wood | 47.60 | -- |{40.82 | -- | -- | | |{38.87 | |
--------------------------------------------------------------------------
The final conclusion drawn from the results is that none of the
processes fulfil the requirements of an ideal method. Those which may
be carried out in a reasonably short time are deficient in two directions:
(1) they yield a 'cellulose' containing more or less oxycellulose; (2) the
celluloses themselves are attacked under the conditions of treatment,
and the end product or cellulose merely represents a particular and at
the same time variable equilibrium, as between the resistance of the
cellulose and the attack of the reagents employed; this attack being by
no means confined to the non-cellulose constituents. Schulze's method
appears to give the nearest approximation to the 'actual cellulose' of
the raw material.
* * * * *
(p. 8) ~SOLUTIONS OF CELLULOSE~--(1) ~ZINC CHLORIDE.~--To
prepare a homogeneous solution of cellulose by means of the neutral
chloride, a prolonged digestion at or about 100° with the concentrated
reagent is required. The dissolution of the cellulose is not a simple
phenomenon, but is attended with hydrolysis and a certain degree of
condensation. The latter result is evidenced by the formation of furfural,
the former by the presence of soluble carbohydrates in the solution
obtained by diluting the original solution and filtering from the
reprecipitated cellulose. The authors have observed that in carefully
conducted experiments cotton cellulose may be dissolved in the reagent,

and reprecipitated with a loss of only 1 p.ct. in weight. This, however,
is a 'net' result, and leaves undetermined the degree of hydration of the
recovered cellulose as of hydrolysis of the original to groups of lower
molecular weights. Bronnert finds that a previous hydration of the
cellulose--e.g. by the process of alkaline mercerisation and removal of
the alkali by washing--enables the zinc chloride to effect its dissolution
by digestion in the cold. (U.S. patent, 646,799/1900. See also p. 59.)
Industrial applications.--(a) Vulcanised fibre is prepared by treating
paper with four times its weight of the concentrated aqueous solution
(65-75° B.), and in the resulting gelatinised condition is worked up into
masses, blocks, sheets, &c., of any required thickness. The washing of
these masses to remove the zinc salt is a very lengthy operation.
To render the product waterproof the process of nitration is sometimes
superadded [D.R.P. 3181/1878]. Further details of manufacture are
given in Prakt. Handbuch d. Papierfabrikation, p. 1703 [C. Hofmann].
(b) Calico-printing.--The use of the solution as a thickener or colour
vehicle, more especially as a substitute for albumen in pigment styles,
was patented by E. B. Manby, but the process has not been industrially
developed [E.P. 10,466/1894].
(c) Artificial silk.--This is a refinement of the earlier applications of the
solution in spinning cellulose threads for conversion into carbon
filaments for electrical glow-lamps. This section will be found dealt
with on p. 59.
(p. 13) (2) ~Cuprammonium solution.~--The application of the solution
of cellulose in cuprammonium to the production of a fine filament in
continuous length, 'artificial silk,' has been very considerably studied
and developed in the period 1897-1900, as evidenced by the series of
patents of Fremery and Urban, Pauly, Bronnert, and others. The
subject will also be found dealt with on p. 58.
* * * * *
(p. 15) ~Reactions of cellulose with iodine.~--In a recent paper, F.

Mylius deals with the reaction of starch and cellulose with iodine,
pointing out that the blue colouration depends upon the presence of
water and iodides. In absence of the latter, and therefore in presence of
compounds which destroy or absorb hydriodic acid--e.g. iodic
acid--there results a brown addition product. The products in question
have the characteristics of solid solutions of the halogen. (Berl. Ber.
1895, 390.)
(24) ~Mercerisation~--Notwithstanding the enormous recent
developments in the industrial application of the mercerising reaction,
there have been no noteworthy contributions to the