Separation of phenols from Eucalyptus wood tar

Isolation of phenols from Eucalyptus wood pyrolysis tar was carried out with the objective of recovering valuable pure phenols, such as phenol, cresols, guaiacol, 4-methylguaiacol, catechol and syringol. The approach included a primary conversion of the raw wood tar into a lighter oil. Phenolic compounds were further separated from the oil by liquid-liquid extraction using alkali and organic solvents. GC/MS analysis of acetyl-derivatized phenolic compounds was used to evaluate the separation method. The primary conversion allowed the isolation of a lighter oil containing the desirable compounds without causing major chemical changes in the distilled oil. Liquid-liquid extraction by alkali and organic solvents essentially yielded a phenolic fraction. Removal of phenols was more efficient under highly alkaline conditions. An evaluation of the analytical procedure for the determination of phenols was also undertaken.