INDUSTRIAL A N D ENGINEERING CHEMISTRY
b4
Dctarminatiav by the Andydod Qroup of the I
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The final fibrous residue ia p-oellulose. Thb varioua frictions (oorrected for ash) gives the hemicellulose content of the unextracted wood. It ia mgnined that the boundary b tween resist9n( hemicelluloses (the eallulosans) and true celt u b s is an arbitrary one and that ohangas in the extraction technique may result in the isolation of somewhat more or less bsmicellulose. However, the sum total of orcelluloae and hemieaUul-i.e., holocellulws-remained rapruducihle in the of two conifers studied. The method permits, for the firat time, B direct pmldmate gravimetric determination of the hemieellulos€a.
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Vol. 17, No. 1
Table I shows the summative rssults ohtgined with (unextracted) redwood and Douglas fir. Acetyl vaiuea on extracted wood, but calculated on the hasis of unextracted wocd, are hicluded because these group are removed during the hemicellulose isolation. The work is being extended to other Conifers. T h e method appears to have the following advantagw: It gives a quantitative picture of the hemicellulose content of the wood and permits furtherinwtigation ofhemicellulose fractions; preliminary removal of extractives is unnecessary; the reagents ealittle degradation of the wood polysaccharidea (Z); the technique in simpk, repmducible, and fairly rapid; and the method permits a summative analysis of wood in which all important componentsmay be determined separately and directlyi.e., in which a summative analysis may he made of the cellulose. hemicellt
Steward. W. T.,Redd. J. C., md Westerbeke. D..J . B i d . C h m . . 135, 188-98 (1940). (2) Javme. G.. Cellulosechnn.. 20. 43-9 (1942). or &e in determirhg stmnc
jellies by the present standard procedure.
Natl. Assoo. Glue Mmufmturers, Ixn. ENP. CHEI., 16, 810 (1924).
(2) Nstl. Assoc. Glue 2, 348 (1930).
Manufsoturera, IN^. ENO.CHZY., ANALED..
