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首页> 外文期刊>Journal of pulp and paper science >Alkali-Resistant Chromophores in Kraft Pulp Xylan
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Alkali-Resistant Chromophores in Kraft Pulp Xylan

机译：牛皮纸浆木聚糖中的耐碱生色团

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摘要

Multiwave ultraviolet/visible detection during size-exclusion chromatography analysis of xylan from hardwood kraft pulps was employed to investigate chromophore changes in 2, 5 and 10% sodium hydroxide solutions at ambient temperature. Changes in absorbance related to the carboxyl (uronic and hexenuronic acids) and carbonyl groups, as well as conjugated heteroaromatic compounds and extended conjugated ones, were monitored at a set of corresponding wavelengths: 210, 234, 280, 350 and 457 nm. Aerobic alkaline destruction of xylan resulted in the redistribution of the chromophores on xylan fragments of vary ing molecular weights, with an accumulation in the molecular weight range ≤ 1000. Conjugated unsaturated furanoids and pyranoids absorbing above 280 nm were found to be alkali resistant. Some discolouration ofxylan due to partly eliminated carbonylconjugated and heteroaromatic-derived extended chromophore structures absorbing at 457 nm was revealed. The extended chromophores were more alkali resistant for kraft oxygen-delignified pulp xylan than for bleached pulp xylan.
机译：利用硬木牛皮纸浆中木聚糖的尺寸排阻色谱分析过程中的多波紫外/可见光检测，研究了环境温度下2、5％和10％氢氧化钠溶液中发色团的变化。在一组相应的波长：210、234、280、350和457 nm下监测与羧基（糖醛酸和己糖醛酸）和羰基以及共轭杂芳族化合物和扩展共轭化合物有关的吸光度变化。木聚糖的好氧碱性破坏导致发色团在分子量变化的木聚糖片段上重新分布，其积累范围≤1000。发现共轭的不饱和呋喃类化合物和吸收超过280 nm的吡喃类化合物具有抗碱性。揭示了由于部分消除了在457 nm吸收的羰基共轭和杂芳族衍生的发色团结构而引起的木聚糖变色。与牛皮纸浆木聚糖相比，扩展的生色团对牛皮纸氧气脱木浆木聚糖的耐碱性更高。

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