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1H-NMR measurement under standard conditions, the methylol -OH signals of MOLC in DMSO-d
6 solutions are found at three different fields but each of them appears as a broad resonance possibly as the result of statistical distribution in the strength of hydrogen bonding between the methylol -OH groups and DMSO molecules. As the methylol groups exist as side chains of high molecular weight cellulose, the hydrogen bonding of the methylol -OH with DMSO is highly affected by the conformation of the polymer chain in the solution. Accordingly, the methylol CH
2 protons which are coupled with the methylol -OH protons must also appear as unresolved resonances in the methylenedioxy region. With the application of the techniques of D
2O exchange, decoupling by double resonance, decoupling by promoting rapid exchange of the hydroxyl protons in the methylol groups of MOLC with the application of high concentration in one case and high temperature in the other, and
13C-NMR with variable temperature, three different methylol CH
2 signals can be confirmed. Assignments of the three peaks are made by comparing the appearance of these signals in MOLC or acetylated MOLC with those in methylolated or acetoxymethylated trityl cellulose. Trityl cellulose with DS of 1.3 was used, in which almost all -OH groups at C-6 and part of the groups at C-2 had previously been blocked by trityl groups.
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