Premium
Engineered Polysaccharides: α‐1,3‐Glucan Acetates Showing Upper Critical Solution Temperature in Organic Solvents
Author(s) -
Heinze Thomas,
Pfeifer Annett,
Koschella Andreas,
Adelman Douglas,
Howe Laurie,
Behabtu Natnael,
Lenges Christian
Publication year - 2019
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201900112
Subject(s) - chemistry , acetic anhydride , acetic acid , polysaccharide , pyridine , acetamide , polymer chemistry , acetyl chloride , organic chemistry , catalysis
Acetates of α‐1,3‐glucan dissolved in N , N ‐dimethyl acetamide/LiCl are prepared by converting the polysaccharide with acetyl chloride, acetic acid anhydride/pyridine, or with acetic acid/ N,N ′‐carbonyl diimidazole. Values of the degree of substitution for the acetyl groups (DS Ac ) of up to 2.6 are realized. NMR spectroscopic measurements reveal a preferred conversion of the primary hydroxyl group at position 6 followed by positions 2 and 4. Depending on the DS Ac , the samples may be soluble in solvents of different polarity at room temperature or at elevated temperatures showing upper critical solution temperature at DS of about 2.5. This process is found to be reversible.