Evaluation of the extent of the oxidation reaction during chlorine bleaching of pulp |
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Authors: | Keiichi Koda Hiroyuki Shintani Yuji Matsumoto Gyosuke Meshitsuka |
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Affiliation: | (1) Laboratory of Wood Chemistry, Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 113-8657 Tokyo, Japan |
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Abstract: | A modified method was developed to evaluate how much chlorine is consumed by the oxidation reaction during the chlorine bleaching process. This evaluation is, in principle, based on the sum of chloride produced during the chlorination stage (C-stage) and produced during alkali treatment of both the C-stage effluent and the chlorinated pulp. Results obtained by this method proved that about 50%–75% of chlorine was consumed by the oxidation reaction during chlorine bleaching, depending on the reaction condition of chlorination. Even under a reaction condition that is not favorable to an oxidation reaction (low pH), approximately three electrons were abstracted from one lignin structural unit by chlorine bleaching. This result provides additional evidence for our recent observation that lignin is extensively oxidized during chlorine bleaching even when pure chlorine without any chlorine dioxide substitution was used.Part of this paper was presented at the 40th Lignin Symposium. Tsukuba, Japan, October 12, 1995 |
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Keywords: | Chlorine bleaching Alkali extraction Oxidation Substitution reaction Chloride Ion chromatography |
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