Lipophilic extractives in Eucalyptus globulus kraft pulps. Behavior during ECF bleaching

authors	Freire, CSR; Silvestre, AJD; Neto, CP
nationality	International
journal	JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY
author keywords	Eucalyptus kraft pulp; ECF bleaching; lipophilic extractives; sterols; fatty acids; long-chain aliphatic alcohols; beta-sitosterol
keywords	CHLORINATED COMPOUNDS; PITCH DEPOSITS; CHEMICAL-COMPOSITION; WOOD EXTRACTIVES; MILL; TCF; GLUCURONOXYLAN; COMPONENTS; AOX
abstract	The composition of E. globulus kraft pulp lipophilic extractives and their behaviour during an ECF (DEDED) bleaching sequence were investigated. Sterols; fatty acids, including several alpha- and omega-hydroxyfatty acids; and long-chain aliphatic alcohols are the major lipophilic extractives of the unbleached pulp. During the bleaching, about 80% of the aliphatic extractives are removed from pulp (ca. 70% of the sterols, 70% of the fatty acids, and 90% of the long-chain aliphatic alcohols). The decrease of sterols is mainly due to the degradation of beta-sitosterol by chlorine dioxide, while the decrease of fatty acids and alcohols is essentially assigned to their extraction and elimination with the alkaline filtrates. The major chemical transformations in pulp extractives composition and structure occur in the last bleaching stages.
publisher	TAYLOR & FRANCIS INC
issn	0277-3813
year published	2005
volume	25
issue	1-2
beginning page	67
ending page	80
digital object identifier (doi)	10.1081/WCT-200058241
web of science category	Materials Science, Paper & Wood
subject category	Materials Science
unique article identifier	WOS:000229998600006