Organosolv delignification of Eucalyptus globulus: Kinetic study of autocatalyzed ethanol pulping

The autocatalyzed delignification of Eucalyptus globulus in 50% ethanol (w/ w) was modeled as the irreversible and consecutive dissolution of initial, bulk, and residual lignin. Their respective contributions to total lignin w as estimated as 9, 75, and 16%. Isothermal pulping experiments were carried out to evaluate an empirical kinetic model among eight proposals correspon ding to different reaction schemes. The calculated activation energy was fo und to be 96.5, 98.5, and 40.8 kJ mol(-1) for initial, bulk, and residual d elignification, respectively. The influence of hydrogen ion concentration w as expressed by a power-law function model. The kinetic model developed her e was validated using data from nonisothermal pulping runs.