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首页> 外文期刊>Journal of Wood Chemistry and Technology >New Insights into Lignin Modification during Chlorine Dioxide Bleaching Sequences (Ⅲ): The Impact of Modifications in the (EO) versus E Stage on the D_1 Stage
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New Insights into Lignin Modification during Chlorine Dioxide Bleaching Sequences (Ⅲ): The Impact of Modifications in the (EO) versus E Stage on the D_1 Stage

机译：二氧化氯漂白过程中木质素修饰的新见解（Ⅲ）：（ EO）对E阶段修饰对D_1阶段的影响

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摘要

Chlorine dioxide deligniflcation (D_0) modifies kraft residual lignin by oxidizing phenolic groups to both quinone and muconic acid structures. Alkaline extraction (E), in addition to removing solubilized lignin, converts quinone moieties to polyphenols. These polyphenols are easily oxidized by oxygen in an (EO) stage or by ClO_2 in a D_1 stage to hydroxyquinones (～1.8mmol/g lignin). Pulps treated by D_0E consume considerably more ClO_2 in the D_1 than D_0(EO), and have lower bleachability, as was quantified by a simple bleaching model. Both D_0E and D_0(EO) pulps approach a common brightness ceiling (～83 ISO) when excess ClO_2 is applied. Examination of the post-D_1 b* values indicates that D_0E and D_0(EO) also have similar asymptotic b* values (～6), indicating that both pulps have similar residual chromophores. Hydroxyquinone structures appear to be eliminated in the D_1 stage for D_0(EO) pulps, and at high ClO_2 levels for D_0E pulps.
机译：二氧化氯去木质素化（D_0）通过将酚基氧化为醌和粘康酸结构来修饰牛皮纸残留的木质素。碱萃取（E）除了除去溶解的木质素外，还将醌部分转化为多酚。这些多酚在（EO）阶段容易被氧气氧化，在D_1阶段容易被ClO_2氧化成羟基醌（〜1.8mmol / g木质素）。用D_0E处理的纸浆在D_1中消耗的ClO_2比在D_0（EO）中要多得多，并且具有较低的漂白性，这是通过简单的漂白模型确定的。当使用过量的ClO_2时，D_0E和D_0（EO）纸浆都接近共同的亮度上限（约83 ISO）。检查D_1后的b *值表明D_0E和D_0（EO）也具有相似的渐近b *值（〜6），表明两个纸浆具有相似的残留生色团。对于D_0（EO）纸浆，在D_1阶段似乎消除了对苯二酚的结构，而对于D_0E纸浆，在高ClO_2含量下被消除了。

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