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Using disaccharides as a kinetic model for alkaline degradation of celluloses and starches
Author(s) -
Ziderman I. Irving,
Belayche Janine
Publication year - 1986
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1986.070320128
Subject(s) - cellobiose , chemistry , maltose , amylose , kinetics , aqueous solution , reaction rate constant , reaction mechanism , cellulose , organic chemistry , starch , catalysis , enzyme , physics , quantum mechanics , cellulase
Degradation kinetics of cellobiose and maltose in hot aqueous solution was determined at pH 9.8 and 13. The positive concentration‐dependence found for the depropagation rate constant of cellobiose indicated that disaccharides decompose more slowly than amyloses under the same reaction conditions, in keeping with a mechanism whereby terminal glucosidic linkages in amylose are also ruptured slowly in an initiation step that is followed by a faster depropagation. Cellobiose termination has a lower activation energy than its depropagation, as does amylose: The opposite result that has been paradoxically ascribed to hydrocellulose is shown to be erroneous. The view that cellobiose does not undergo a chemical stopping reaction appears to be unjustified. The status of a “single‐chain” mechanism for 1,4‐glucan depropagation is discussed, and is considered to occur with cellobiose, maltose, hydrocellulose, and hydroamylose.