Determination of the Distribution of the Substituent Group in Cellulose Acetate by Full Assignment of Au Carbonyl Carbon Peaks of 13C{1H} NMR Spectra
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- Kowsaka Keisuke
- Fundamental Research Laboratory of Fiber and Fiber-Forming Polymers, Asahi Chemical Industry Co., Ltd.
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- Okajima Kunihiko
- Fundamental Research Laboratory of Fiber and Fiber-Forming Polymers, Asahi Chemical Industry Co., Ltd.
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- Kamide Kenji
- Fundamental Research Laboratory of Fiber and Fiber-Forming Polymers, Asahi Chemical Industry Co., Ltd.
書誌事項
- タイトル別名
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- Determination of the distribution of the substituent group in cellulose acetate by full assignment of all carbonyl carbon peaks of 13C{1H} NMR spectra.
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説明
An attempt was made to assign a number of peaks, observed in carbonyl region (168—171 ppm) of 13C{1H} NMR spectra of cellulose acetate (CA), to twelve magnetically different acetyl groups existing in 8 kinds of glucopyranose units constituting CA. CA samples with total degree of substitution «F» ranging 0.43 to 2.46 were prepared by acid-hydrolysis of CA with «F»=2.92 dissolved in acetic acid. 13C{1H} NMR measurements were made on these ten CA samples in deuterated dimethylsulfoxide and 14 peaks in total were observed definetely over the whole range of «F» from 2.92—0.43. From the spectra of CA samples with highest «F» (2.92) and lowest (0.43) carbonyl carbon peaks at C6, C3, and C2 positions in trisubstituted and monosubstituted glucopyranose units were successfully assigned. Deducing the effect of an acetyl group on the chemical shift of other acetyl groups, and vise versa, based on an empirical rule, 6 carbonyl carbon peaks in 3 kinds of disubstituted glucopyranose units were assigned. Eight average molar fractions «flmn» (l=1 or 0 means that a hydroxyl group attached directly at C2 position is or is not substituted and m=1 or 0 means that C3 position is or is not substituted, and n corresponds to C6 position) [i.e., «f000», «f100», ···, «f111»] were evaluated from integrated intensity ratios. The probability of substitution at Ck position «fk» (k=2, 3, and 6) and «F», both evaluated from the above «flmn» values, fairly agree with those estimated by the conventional NMR method, indicating the validity of the assignment in this paper.
収録刊行物
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- Polymer Journal
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Polymer Journal 20 (10), 827-836, 1988
The Society of Polymer Science, Japan
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詳細情報 詳細情報について
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- CRID
- 1390282681266392576
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- NII論文ID
- 130004768022
- 30001928141
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- COI
- 1:CAS:528:DyaL1MXisFGmuw%3D%3D
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- ISSN
- 13490540
- 00323896
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- 本文言語コード
- en
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- データソース種別
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- JaLC
- Crossref
- CiNii Articles
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- 抄録ライセンスフラグ
- 使用不可
