An unconventional system for cellulose acetate hydrolysis, consisting of homogeneous mixtures of benzene/acetic acid/water of different compositions, was investigated from the perspective of kinetics and also with respect to the degradation of the cellulosic chains during the process. It was observed that the decrease of the degree of substitution of the polymer occurs with higher reaction rate than that in the reference system, free of benzene, and depends on the composition of the reaction medium. A pseudo-first-order kinetic law satisfactorily describes the deacetylation process performed in the presence of benzene. Also, the degradation of the polymeric chain during the process is dependent on the presence of the hydrocarbon and on the composition of the reaction system used. A lower degradation rate was found to characterize the first period of the process, compared with that produced in a benzene-free system. These peculiarities were explained by the influence of benzene on the composition of solvent shell in the vicinity of macromolecules. (C) 2004 Wiley Periodicals, Inc.