THE ROLE OF EXTRACTIVES DURING VACUUM PYROLYSIS OF WOOD

Vacuum pyrolysis of wood, extractive‐free wood, holocellulose, and Avicel was conducted and their oil yields were compared. Formic and acetic acids and levoglucosan contents of all the oil products were determined. Molecular beam mass spectrometry analysis of wood and extractive‐free wood and their pyrolysis oils was performed. CO2 and CO, the main pyrolysis gases, were measured for each pyrolysis experiment. The role of extractives and the modification in wood cellulosic structure, which occurred during wood extraction treatment process, were investigated. Extractives, lignin, and orientation of the cellulosic fibers all significantly influenced the production of pyrolysis oils and formic acid. Lignin and extractives exhibited an inhibiting effect for the production of acetic acid and levoglucosan, respectively. CO2 and CO yields were affected by the presence of extractives and by the cellulosic fiber orientation. Copyright © 1990 John Wiley & Sons, Inc.