Abstract
The hemicellulose preparation used in this investigation has been isolated from pectin-free sawdust of elm wood (Ulmus Davidiana Planch. var. Japonica NAKAI.) by the extraction with cold 4% NaOH.
The hemicellulose is a white powder which does not reduce Fehling's solution and gives no blue coloration with iodine, but gives positive naphthoresorcin test of uronic acids and their anhydrides, and it is laevo-rotatory : [α]18°D=-96.0° in 2% NaOH solution.
The hemicellulose gives d-xylose and xyloglucuronic acid on the acid hydrolysis and possesses analytically a molar ratio of sugar units of approximately 9 d-xylose to glucuronic anhydride, therefore, it may be naturally concluded that the hemicellulose consists of d-xylose and xyloglu-curonic acid units, which molar ratio is approximately eight to one, that is, the composition of hemicellulose may be expressed by the following formula: [(C5H8O4)8•(C5H8O4•C6H8O6)1]n.
