Eiko Nakayama

Substituent Distribution of Cyanoethyl Cellulose

Estimation of the substitution distribution for cyanoethyl cellulose was carried out by 1H and 13C NMR spectroscopic analyses after the additional acetylation. Based on the complemental function of cyanoethyl and acetyl substituents, the degree of substitution (DS) of cyanoethyl groups could be calculated from the ratios of the 1H integrated intensities in acetyl methyl (δ 1.8–2.1) and cyanoethyl methylene (δ 2.6–2.9) protons, and also from the corresponding ratios for acetyl methyl carbon signals (δ 19.7–21.3) and cyanoethyl methylene carbon signals (δ 17.5–19.0). Good agreement was obtained between the DS values obtained from the NMR spectroscopic analyses and those determined by the conventional nitrogen content method, indicating the validity of the NMR method used. In addition, the NMR method was found to be effective in determining the positional substituent distribution by the quantitative analysis of the three cyan carbon signals (δ 118–120).