ON THE SIGNIFICANCE OF THE SUPEROXIDE RADICAL (O-2 RADICAL-ANION/HO2) IN OXIDATIVE DELIGNIFICATION, STUDIED WITH 4-T-BUTYLSYRINGOL AND 4-T-BUTYLGUAIACOL .4. THE MECHANISM OF AROMATIC RING-OPENING

被引:63
作者
GIERER, J [1 ]
YANG, EQ [1 ]
REITBERGER, T [1 ]
机构
[1] ROYAL INST TECHNOL,DEPT CHEM,DIV NUCL CHEM,S-10044 STOCKHOLM,SWEDEN
关键词
SUPEROXIDE ANION RADICAL; HYDROPEROXYL RADICAL; HYDROXYL RADICAL; PHENOXYL RADICAL; LIGNIN MODEL COMPOUND; AROMATIC RING; MECHANISM; GAMMA RADIOLYSIS; 4-T-BUTYLSYRINGOL; 4-T-BUTYLGUAIACOL;
D O I
10.1515/hfsg.1994.48.5.405
中图分类号
S7 [林业];
学科分类号
0829 ; 0907 ;
摘要
Using gamma-irradiation under carefully controlled conditions, the reactions of phenoxyl radicals from lignin model compounds of the guaiacol and syringol types with superoxide anion radicals (O-2 (radical anion)) or their protonated forms, hydroperoxyl radicals (HO2.), were studied. The reaction mixtures obtained after irradiation at different pH's were analysed, and feasible pathways for the formation of the major products were proposed. The results reveal that, in alkaline media, superoxide anion radicals mainly bring about opening of the aromatic rings, whereas in acidic media hydroperoxyl radicals may predominantly cause demethoxylation.
引用
收藏
页码:405 / 414
页数:10
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