Acetic Acid Based Pulping, 1992 Solvent Pulping Symposium Proceedings

A variety of variations on acetic acid pulping have been developed over the years and several new acetic acid based processes are currently under development. An analysis is given of the types of variations in acetic acid pulping which have been explored in the past and of the pulp properties realized in these processes. Previous acetic acid based processes have utilized high and low temperatures, catalysts and cosolvents. Mineral acid catalysts have been utilized to varying degrees of success. Methods for strength improvement of acetic acid pulps are discussed.

Lignin removal and recovery are analyzed. The importance of swelling the lignocellulosic gel is emphasized for lignin removal. The molecular weight characteristics of lignin from acetic acid based pulping of wood are described in relation to liquor composition and degree of delignification. It appears that rapid delignification is associated with removal of large lignin fragments.

Finally, a description of our efforts to develop a low temperature, continuous distillation acetic acid ased process are described along with other new developments in the field of organic acid pulping.