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Showing papers on "SISAL published in 1967"


Journal ArticleDOI
TL;DR: Partial acid hydrolysis of sisal hemicellulose yields mainly xylose and 2-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-xylopyranose as mentioned in this paper.
Abstract: Sisal fibre holocellulose was extracted with alkaline solutions of increasing concentration and finally with alkaline borate solution. Hemicellulose fractions (1–4) were isolated from the extracts. Fractions 2 and 3 have molecular weights of 23,700 ± 500 and 25,300 ± 500, respectively. Analytical data are recorded for each fraction.Partial acid hydrolysis of sisal hemicellulose yields mainly xylose and 2-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-xylopyranose. The main hemicellulose fraction (2) was methylated and hydrolysed, affording 2,3,4-tri-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 3-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyluronic acid)-3-O-methyl-D-xylopyranose in the approximate molar proporation of 1:31·9:1·5:5. The methylated polysaccharide has a degree of polymerisation of 109 ± 3. On this basis and from other evidence it is suggested that the hemicellulose is composed of chains of ca. 97 1,4-linked β-D-xylopyranose residues, approximately every eighth residue carrying a terminal 4-O-methyl-α-D-glucopyranosyluronic acid residue linked through position-2. A small degree of branching in the xylan is indicated.

7 citations