NMR characterization of methylcellulose: Chemical shift assignment and mole fraction of monomers in the polymer chains

被引：21

作者：

Kono, Hiroyuki ^{[1
]}

Fujita, Sayaka ^{[1
]}

Tajima, Kenji ^{[2
]}

机构：

[1] Natl Inst Technol, Tomakomai Coll, Div Appl Chem & Biochem, Nishikioka 443, Tomakomai, Hokkaido 0591275, Japan

[2] Hokkaido Univ, Fac Engn, Kita Ku, N13W8, Sapporo, Hokkaido 0608628, Japan

来源：

CARBOHYDRATE POLYMERS | 2017年 / 157卷

关键词：

Methylcellulose; Substituent distribution; Monomer composition; Nuclear magnetic resonance; Steric hindrance; SUBSTITUENT DISTRIBUTION; CARBOXYMETHYL CELLULOSE; PHYSICAL-PROPERTIES; MAGNETIC-RESONANCE; METHYL CELLULOSE; DERIVATIVES; WATER; ADDITIVITY; HYDROGELS; ALKANES;

D O I：

10.1016/j.carbpol.2016.10.056

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

Methylcellulose samples with different degrees of substitution were prepared by a heterogeneous reaction of cellulose. Two-dimensional NMR spectroscopy provided complete assignment of the H-1 and C-13 chemical shifts of the un-, 2-mono-, 3-mono-, 6-mono-, 2,3-di-, 2,6-di-, 3,6-di-, and 2,3,6-tri-substituted anhydroglucose units (AGUs). Comparative analysis of the chemical shift data revealed the relationship between the methyl substituents at the 2-, 3-, and 6-positions and the 1H and 13C chemical shifts of the AGUs; additivity could be applied to the H-1 and C-13 chemical shifts of methylcellulose. Quantitative C-13 NMR spectra of the samples determined the composition of the eight AGUs and the substituent distribution at the 2-, 3-, and 6-positions of cellulose. This provided estimations of the hydroxyl group reactivity toward methylation and the interactions between the substituent groups within the same AGU. (C) 2016 Elsevier Ltd. All rights reserved.

引用

页码：728 / 738

页数：11

共 34 条

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