The main phenomena involved in pine wood processing with HCl-catalyzed acetic acid media (wood solubilization, delignification, degradation of both cellulose and hemicellulose, and generation of hemicellulosic sugars and furfural) were studied. The effects of both reaction time (in the range 0-180 min) and catalyst concentration (in the range 0.15-0.45%) on pulp yield, residual Lignin, polysaccharide degradation, and hemicellulosic sugar generation were correlated by phenomenological kinetic models developed for the two operational temperatures considered (115 or 130 degrees C). The models (based on pseudohomogeneous, first-order kinetics) provided a good interpretation of the experimental data.