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1H n.m.r. study on the ring opening selectivity of aromatic dianhydrides towards methanol

โœ Scribed by Wenxi Huang; Lianxun Gao; Zhenhua Yang; Xin Zhang; Jiping Xu; Mengxian Ding

Publisher
Elsevier Science
Year
1997
Tongue
English
Weight
472 KB
Volume
38
Category
Article
ISSN
0032-3861

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โœฆ Synopsis

Several isomeric aromatic diester-diacids may appear as a result of the opening selectivity of anhydride groups towards the alcohol. 1H n.m.r, was thus used to characterize the isomeric structure and to quantify the isomer composition. It was found that the isomer ratios quantitatively correlate with electron affinity of bridged dianhydrides and is independent of the alcohol structure used. Furthermore, the 1H n.m.r chemical shift of bridged diester-diacids was found to be a very sensitive probe of chemical nature of bridged groups and can be used as indices of the opening selectivity.

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