C. S. R. Freire, A. J. D. Silvestre, C. Pascoal Neto
Oxidized Derivatives of Lipophilic Extractives Formed during Hardwood Kraft Pulp Bleaching
Summary
The structural changes of E. globulus wood extractives during bleaching with chlorine dioxide (D),
oxygen (O), ozone (Z) and hydrogen peroxide (P) were studied. The detailed characterisation of
the extractive derivatives detected in the partially bleached D, O, P and Z pulps was achieved by
performing reactions of pure reference compounds with the different bleaching agents. The results
show that the unsaturated sterols and fatty acids are extensively degraded during chlorine dioxide
and ozone bleaching and only partially degraded during oxygen and hydrogen peroxide bleaching.
The corresponding saturated extractives as well as the long chain aliphatic alcohols and ?-hydroxyfatty
acids were stable during bleaching. The main oxidation products of ?-sitosterol and oleic
and linoleic acids, including one chlorinated derivative of linoleic acid, were identified here for the
first time in E. globulus bleached pulps and bleaching filtrates.
Holzforschung, Walter de Gruyter
Print ISSN: 0018-3830
Volume: 57, 08/2003
Pages: 503 - 512
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