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首页> 外文期刊>Journal of pulp and paper science >The Effect of Phenolic and Nonphenolic Lignin Model Compounds on the Degradation of Cellobiose during Ozonation - pH Dependence
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The Effect of Phenolic and Nonphenolic Lignin Model Compounds on the Degradation of Cellobiose during Ozonation - pH Dependence

机译：酚和非酚木质素模型化合物对臭氧化过程中纤维二糖降解的影响-pH依赖性

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摘要

There are two undesirable reactions that occur during ozone bleaching of kraft pulp. One is hydroxyl radical formation that occurs when ozone decomposes prior to reaction with lignin. The other one is one-electron oxidation of dissociated phenolate in lignin, from which an hydroxyl radical is also formed as in the decomposition reaction of ozone. To improve the reaction selectivity during ozone bleaching, suppression of these radical formations in acidic solution was investigated using cellobiose, veratryl alcohol andvanillyl alcohol. At pH 2 and 0.7, hydroxyl radical formation from the decomposition of ozone was suppressed completely as a result of a simple decrease of hydroxyl onions. However, the radical formation initiated from one-electron oxidation of phenolate could not be completely suppressed. Therefore, it was concluded that ozone may be able to extract hydrogen, even from an undissociated phenolic hydroxyl group, to initiate one-electron oxidation.
机译：在牛皮纸浆的臭氧漂白过程中会发生两个不良反应。一种是羟基自由基的形成，它是在臭氧与木质素反应之前分解时发生的。另一个是木质素中解离的酚盐的单电子氧化，与臭氧的分解反应一样，木质素也从中形成羟基。为了提高臭氧漂白过程中的反应选择性，使用纤维二糖，藜芦醇和香草醇研究了在酸性溶液中抑制这些自由基形成的方法。在pH 2和0.7下，由于简单地减少了羟基洋葱，因此完全抑制了臭氧分解产生的羟基自由基。但是，不能完全抑制由酚盐的单电子氧化引发的自由基形成。因此，可以得出结论，即使从未离解的酚羟基中，臭氧也能够提取氢以引发单电子氧化。

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