ISSN:
0449-296X
Schlagwort(e):
Physics
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
A number of 1,6-anhydrides were polymerized in the melt at 115°C by use of monochloroacetic acid as catalyst. In the early stages of polymerization (up to 40-50% monomer consumed), each monomer was found to disappear by a first-order rate process. The 1,6-anhydrides investigated and their relative rates of polymerization were: 1,6-anhydro-2-O-methyl-β-D-glucopyranose, 1.0; 1,6-anhydro-3,4-di-O-methyl-β-D-glucopyranose, 1.4; 1,6-anhydro-2-O-methyl-β-D-galactopyranose, 2.3; 1,6-anhydro-3-O-methyl-β-D-glucopyranose, 2.6; 1,6-anhydro-4-O-methyl-β-D-glucopyranose, 6.3; 1,6-anhydro-4-O-(β-D-glucopyranosyl) β-D-glucopyranose, 9.0; 1,6-anhydro-β-D-galactopyranose, 17; 1,6-anhydro-β-D-glucopyranose, 37; 1,6-anhydro-β-D-mannopyranose, 91; and 1,6-anhydro-2-deoxy-β-D-arabino-hexopyranose, 240. The effect of substitution on the rate of polymerization suggests this reaction is mechanistically related to the acid hydrolysis of pyranosides. The results suggest that polymerization proceeds in two stages: (1) an initial build-up of dimer followed by (2) a slower growth to higher molecular weight material.
Zusätzliches Material:
3 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1971.150091010
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