Partial hydrolysis of cellulose acetate in toluene/acetic acid/water system

AbstractThe partial hydrolysis of cellulose acetate was studied in homogeneous toluene/acetic acid/water media of different compositions using sulfuric acid as a catalyst. The presence of toluene considerably increases the hydrolysis rate. Products with a degree of substitution (DS) of about 1.70, useful for further derivatization, were obtained at 60°C with 15–34 wt.‐% toluene in the reaction medium and without addition of water during the process in shorter times than in the conventional procedure free of toluene. The kinetic behaviour of toluene‐containing systems is dependent on the composition of the reaction medium, as well as on the temperature. The reaction systems with 15 wt.‐% and 20 wt.‐% toluene, respectively, were found to obey a linear relationship of ‐ln(DS/DS0) versus time. The behaviour of the studied reaction systems is tentatively explained by an enrichment of the solvation shell in water and sulfuric acid, since the acidity function of the sulfuric acid was not influenced by the presence of toluene. The hydrolysed products obtained by the described procedure are soluble in some common organic solvents used for derivatization, such as dimethylformamide, acetic acid and dimethyl sulfoxide.