BULLETIN
18
U.
309,
S.
DEPARTMENT OF AGRICULTURE.
CELLULOSE FROM ZACATON.
The sample sent for examination was bleached pulp of Epicampes macroura in the form of waterleaf sheets. The purpose of the work upon it was to determine the nature of its cellulose as completely as possible. (a) Fuchsin-sulphurous acid (Schiff's reagent) First, qualitative tests were tried, turned a bit of the pulp pink on standing a few minutes. (6) Sachsse's solution (alka(c) Fehling's solution was line HgI 2 ,2KI) was reduced on boiling with the pulp, reduced on boiling with the pulp, (d) Vitz's methylene-blue test (boiling a bit of the pulp for 15 minutes with 0.5 per cent aqueous solution of methylene blue) dyed the pulp deep blue, which was not removed by long washing. A bit of pure rag paper
was put in the dye at the same time, as a check. It dyed light blue and washed nearly white under the same conditions of treatment, (e) Phenylhydrazin acetate boiled with the pulp gave a yellow hydrazone. (/) Ferric ferricyanid (Cross and Bevan) gave a blue precipitate with the pulp on standing some minutes. According to Cross and Bevan, this reaction is a quantitative measure of lignin. Later work has shown, however, that oxycellulose gives the same precipitate, (g) On distilling from a suspension of the pulp in hydrochloric acid of 1.06 specific gravity and adding a phloroglucin solution to the distillate, a large amount of furfural phloroglucid was precipiThese reactions show conclusively that the sample contained oxycellulose in tated. considerable quantity.
As oxycellulose of
is
quite sensitive to attack
importance to determine
how much was
by many
destructive agencies,
it
was
in this sample from Epicampes macroura
In the present state of knowledge (which, unforturather a state of ignorance) of the constitution of cellulose, it is impossible However, it is easy to compare to say how much of any given sample is oxycellulose.
in relation to other celluloses. nately,
is
samples and determine which has more or less of it. Accordingly, comparative quantitative determinations were made of (1) copper number and (2) furfural yield on the cellulose from Epicampes macroura, a bleached soda poplar pulp, and on cotton "cellulose" simultaneously. The "copper number" of Schwalbe is the number of grams of copper precipitated by boiling 100 grams of the pulp in question for 15 minutes with Fehling's solution, under certain definite conditions of concentration, heating, and so on. In the absence of other reducing substances it is an admirable measure of oxycellulose; hence, it was used here with a modified Low volumetric method of determining the copper instead of Schwalbe's slower and no more accurate electrolytic method. It is at once evident that the Epicampes cellulose contains slightly more oxycellulose than the poplar pulp and much more than the cotton. (Contrary to the commonly accepted belief, the writers have found most cotton cellulose to contain a little oxycellulose, as
shown by many
tests.)
For further confirmation and comparison, simultaneous quantitative estimations of the furfural yield from the same cotton, poplar pulp, and Epicampes pulp were made, following the method of Flint and Tollens. This, of course, would not be applicable in the presence of wood gums or various other pentosans or furfurosans, but was here applicable because the other furfural-yielding groups were absent. The numerical results of these two analyses are shown in Table III.
