C-13-NMR STUDIES ON ACETYLATED WOOD - DIS TRIBUTION OF ACETYL SUBSTITUENTS IN THE COURSE OF ACID-HYDROLYSIS

Acid-catalyzed hydrolyses of acetates in acetylated cellulose powder a nd acetylated wood meal (Pinus densiflora Sieb. and Zucc.) were analyz ed by the C-13-NMR (carbon 13 nuclear magnetic resonance) method. The total degree of substitution, (TDS)NMR, thus estimated as the sum of t he relative degree of substitution (RDS) of each hydroxyl group at the C-2, C-3, and C-6 positions of the glucose ring, was in good agreemen t with the total degree of substitution determined by the titration me thod, (TDS)tit, for acetylated cellulose powder, but was a little larg er than the TDS(tit) for acetylated wood meal. The relative rate and e quilibrium constants of the deacetylation process were estimated for a cetylated cellulose powder on the basis of these RDS values. Experimen tally, hydrolysis was shown to be less reactive and less selective for acetylated wood meal than for acetylated cellulose powder.