ISSN:
0449-296X
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Past experimental evidence has indicated that the acid-catalyzed hydrolysis of polysaccharides does not proceed randomly, and it has been suggested that hydrolysis is more rapid for the glycosidic bonds by which the nonreducing endgroups are attached. To test this hypothesis, amylose and cellulose were permethylated and subjected to methanolysis. It was found that in both the methanolysis of tri-O-methylamylose and tri-O-methylcellulose the production of methyl 2,3,4,6-tetra-O-methyl-α,β-D-glucopyranoside was complete before the production of methyl 2,3,6-tri-O-methyl-α,β-D-glucoside was finished. Since the former compound could only come from the original nonreducing end units and the latter from all other units, these results were interpreted as giving support to the idea of a preferential scission of the bonds at the nonreducing ends, even though the release of original end units was not complete until 70-85% of the glycosidic bonds had been cleaved. It was concluded that methanolysis proceeds by a modification of the hydrolysis mechanism and that methanolysis is therefore a poor model for hydrolysis.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1967.150050829
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