title: Effect of oxygen, ozone and hydrogen peroxide bleaching stages on the contents and composition of extractives of Eucalyptus globulus kraft pulps.
abstract: The effects of oxygen (O), ozone (Z) and hydrogen peroxide (P) bleaching stages on the composition and total amount of Eucalyptus globulus kraft pulp lipophilic extractives was studied. These bleaching stages led to the partial removal and to several oxidative transformations of fatty acids and sterols, the main lipophilic extractives found in the unbleached pulp. Unsaturated extractives were found to be partially degraded while saturated ones were, in general, stable. The oxygen and hydrogen peroxide bleaching stages were more effective than ozone in removing fatty acids from pulp, by dissolution in the liquid phase. On the other hand, the ozone stage was more effective in the oxidative degradation of sterols. Oxygen and hydrogen peroxide bleaching stages were also effective in sterols removal, but led to the formation of sterol oxidation derivatives, previously shown to be involved in the formation of pitch that accumulates in the bleaching filtrates.
authors.affiliation: University of Aveiro, CICECO and Department of Chemistry, 3810-193 Aveiro, Portugal.
authors.forename: Carmen S R
authors.initials: CS
authors.lastname: Freire
authors.forename: Armando J D
authors.initials: AJ
authors.lastname: Silvestre
authors.forename: Carlos
authors.initials: C
authors.lastname: Pascoal Neto
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Evtuguin
mesh_terms: D005052:Eucalyptus / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*
chemical_list: D016877:Oxidants; D010126:Ozone; D006861:Hydrogen Peroxide; D010100:Oxygen