Determination of substituent distribution in cellulose acetate by means of a 13C NMR study on its propanoated derivative

✍ Scribed by Yasuyuki Tezuka; Yoshikazu Tsuchiya

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 395 KB
• Volume: 273
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(95)00107-5

✦ Synopsis

Cellulose acetate (1) is commercially important, and is produced with various degrees of substitution (DS) suitable for such applications as fibers, plastics, films, and coatings [1]. The final properties of these products may be optimized through control of the distribution pattern of acetyl groups on the glucose residue [2-5], as well as the total DS by acetyl groups. In consequence, a convenient and reliable analytical technique is important for both the elucidation of structure-properties relationships and for quality control in the production process.

Although the total acetyl content in samples of 1 is readily determined by means of a standard titration technique [6,7], the individual DS at 0-2, -3, and -6 in the glucose residue is not readily obtainable through chromatographic techniques.

A 1H NMR spectroscopic technique applied with derivatized samples of 1 [4,8] involves conversion of residual hydroxyl groups into the deuterated acetyl groups through reaction with acetyl chloride-d 3. The acetyl proton signals of the resulted cellulose triacetate appear as three lines corresponding to the 2-, 3-, and 6-OAc signals in the glucose residues. Perdeuterioacetylation avoids the spectral complication observed in the acetyl-proton signals of partially substituted 1.

Part 10 of a series: 1H and 13C NMR Structural Study on Cellulose and Polysaccharide Derivatives with Carbonyl Groups as a Sensitive Probe. For the preceding papers, see ref. [21].