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首页> 外文期刊>Journal of Wood Chemistry and Technology >REVISITING THE MECHANISM OF beta-O-4 BOND CLEAVAGE DURING ACIDOLYSIS OF LIGNIN. PART 6: A REVIEW
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REVISITING THE MECHANISM OF beta-O-4 BOND CLEAVAGE DURING ACIDOLYSIS OF LIGNIN. PART 6: A REVIEW

机译：回顾木质素酸化过程中β-O-4键断裂的机理。第六部分：回顾

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摘要

This paper reviews our results on the acidolysis of dimeric non-phenolic beta-O-4-type lignin model compounds in aqueous 82% 1,4-dioxane containing an acid at 85 degrees C. It was shown that the mechanism of a C-6-C-2-type model compound, 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl) ethanol IX, is fairly different from that of a C-6-C-3 analogue, 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl) propane-1,3-diol XX, suggesting the significance of the presence of the gamma-hydroxymethyl group. It was confirmed that the hydride transfer mechanism exists as a reaction route of the benzyl-cation-type intermediates derived from both compounds, and the contribution of this mechanism is greater than expected in the acidolysis of compound XX. An enol ether compound, 2-(2-methoxyphenoxy)-3-(3,4-dimethoxyphenyl) prop-2-en-1-ol, was first detected in the acidolysis of compound XX using the DBr/D2O/1,4-dioxane system. It was confirmed in the acidolysis of compound XX using HBr that the mechanism is different from that in the system using either HCl or H2SO4 and an unknown mechanism contributes to the reaction. This unknown mechanism surprisingly contributed more with decreasing concentration of HBr or Br-, provided that Br- still existed in the system.
机译：本文综述了我们在85°C下在含酸的82％1,4-二恶烷水溶液中酸解二聚非酚β-O-4-型木质素模型化合物的结果。结果表明，C-的机理6-C-2-型模型化合物2-（2-甲氧基苯氧基）-1-（3,4-二甲氧基苯基）乙醇IX与C-6-C-3类似物2-（2 -甲氧基苯氧基）-1-（3,4-二甲氧基苯基）丙烷-1,3-二醇XX，表明存在γ-羟甲基的重要性。证实了氢化物转移机理作为衍生自两种化合物的苄基阳离子型中间体的反应途径存在，并且该机理的贡献大于化合物XX的酸解中的预期。首先使用DBr / D2O / 1,4在酸解化合物XX中首先检测到一种烯醇醚化合物2-（2-甲氧基苯氧基）-3-（3,4-二甲氧基苯基）丙-2-烯-1-醇-二恶烷系统。在使用HBr酸解化合物XX时，已确认其机理与使用HCl或H2SO4的体系中的机理不同，并且未知的机理对该反应有所贡献。如果系统中仍然存在Br-，则这种未知的机制令人惊讶地随着HBr或Br-浓度的降低做出了更多贡献。

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