AN APPROACH TO UNDERSTANDING THE MECHANISM OF PROTECTION OF BLEACHED HIGH-YIELD PULPS AGAINST PHOTOYELLOWING BY REDUCING AGENTS USING THE LIGNIN MODEL DIMER - 3,4-DIMETHOXY-ALPHA-(2'-METHOXYPHENOXY)-ACETOPHENONE

被引：37

作者：

CASTELLAN, A ^{[1
]}

ZHU, JH ^{[1
]}

COLOMBO, N ^{[1
]}

NOURMAMODE, A ^{[1
]}

DAVIDSON, RS ^{[1
]}

DUNN, L ^{[1
]}

机构：

[1] CITY UNIV LONDON,DEPT CHEM,LONDON EC1V 0HB,ENGLAND

来源：

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY | 1991年 / 58卷 / 02期

关键词：

D O I：

10.1016/1010-6030(91)85052-I

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 [物理化学]; 081704 [应用化学];

摘要：

The effect of reducing agents on the photodegradation of an O-methylated alpha-carbonyl beta-O-4 lignin model dimer was studied in detail. The agents did not suppress the photodegradation but altered the photoproduct distribution to a minor extent and in an unpredictable way. Thus the reagents do not affect the primary photochemical process. However, a number of the compounds, e.g. Rongalit C and thiourea dioxide, suppressed the yellowing processes accompanying the degradation. This can be attributed to the reducing agents which alter the outcome of the photochemical processes of the oligomer produced in the reactions; indeed the reducing agents effectively photobleach the coloured products. The reducing agents which prevented photoyellowing when the beta-O-4 compound was irradiated also prevented the photoyellowing of high-yield pulp, provided that the pulp was irradiated in solutions of the reducing agents. It is concluded that the reducing agents destroy peroxidic and coloured entities which contribute to the discoloration process.

引用

页码：263 / 273

页数：11

共 34 条

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