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首页> 外文期刊>Journal of Applied Polymer Science >Evaluation of the contribution of lignin stilbene phenol units in the photoyellowing of peroxide-bleached lignin-rich pulps
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Evaluation of the contribution of lignin stilbene phenol units in the photoyellowing of peroxide-bleached lignin-rich pulps

机译：评估木质素二苯乙烯酚单元在过氧化物漂白富木质素纸浆光致黄变中的作用

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摘要

In order to assess and quantify the contribution of stilbene phenols in photoreversion of bleached high-yield pulps, a method to reduce the stilbene double bond and quantify the formed diphenylethane was developed on 4-benzyloxy-3,3'-dimethoxy-4'-hydroxystilbene, as lignin monomer model, and also on a more sophisticated lignin polymer model constituted by a polystyrene framework containing 4,4'-dihydroxy-3,3'-dimethoxystilbene elements as pendent groups. The method used RhCl( PPh3)(3) as soluble catalyst to get an efficient hydrogenation and AlCl3 in benzene to liberate the diphenylethane from the polymer framework. For the first time a semiquantitative evaluation of the content of the stilbene phenols formed from P-l units was given for high-yield pulps. The value of 2 p-stilbene phenols for 1000 C-9 lignin units found indicates that they are present in very small quantities after the peroxide bleaching. UV irradiation of the polystyrene model adsorbed on solid cellulose matrix had revealed an efficient stabilization after the hydrogenation treatment. This was not the case for the peroxide bleached pulp showing that the p-stilbene phenols formed from beta-1 units are not the main contributors of the rapid yellowing of bleached lignin-rich pulps. (C) 1998 John Wiley & Sons, Inc. [References: 35]
机译：为了评估和量化二苯乙烯酚在漂白高得率纸浆的光还原中的贡献，开发了一种在4-苄氧基-3,3'-二甲氧基-4'-上还原二苯乙烯双键并量化形成的二苯乙烷的方法。羟基二苯乙烯作为木质素单体模型，并且在更复杂的木质素聚合物模型上，该模型由包含4,4'-二羟基-3,3'-二甲氧基二苯乙烯元素作为侧基的聚苯乙烯骨架构成。该方法使用RhCl（PPh3）（3）作为可溶性催化剂以实现有效的加氢作用，并使用AlCl3在苯中从聚合物骨架中释放出二苯乙烷。对于高收率的纸浆，第一次对由P-1单元形成的二苯乙烯酚的含量进行了半定量评估。对于1000 C-9木质素单元，发现2种对苯乙烯酚的值表明，过氧化物漂白后它们的存在量很小。吸附在固体纤维素基体上的聚苯乙烯模型的紫外线辐射显示了氢化处理后的有效稳定作用。过氧化物漂白纸浆不是这种情况，表明由β-1单元形成的对二苯乙烯酚不是漂白的富含木质素纸浆快速变黄的主要起因。 （C）1998 John Wiley＆Sons，Inc. [参考：35]

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