2,5-dihydro-4-[(2-hydroxy-3-methoxy-5-methylphenyl)methyl]-2-methyl-5-oxo-2-furanacetic acid

• 分子结构分类: 有机化合物 - 苯类化合物 - 酚类
• 英文名称: 2,5-dihydro-4-[(2-hydroxy-3-methoxy-5-methylphenyl)methyl]-2-methyl-5-oxo-2-furanacetic acid
• 英文别名: 2-[4-[(2-Hydroxy-3-methoxy-5-methylphenyl)methyl]-2-methyl-5-oxofuran-2-yl]acetic acid；2-[4-[(2-hydroxy-3-methoxy-5-methylphenyl)methyl]-2-methyl-5-oxofuran-2-yl]acetic acid
• 化学式: C₁₆H₁₈O₆
• 分子量: 306.315
• InChiKey: DFMKTESCMYPYHL-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.9
• 重原子数：
  22
• 可旋转键数：
  5
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.38
• 拓扑面积：
  93.1
• 氢给体数：
  2
• 氢受体数：
  6

反应信息

• 作为产物：
  描述：

  2-[(2-羟基-3-甲氧基-5-甲基苯基)甲基]-6-甲氧基-4-甲基苯酚 在 sodium hydroxide 、 双氧水 、 锰 作用下， 反应 2.0h， 生成 柠康酸 、 、 2-[(2-hydroxy-3-methoxy-5-methylphenyl)methyl]-4-oxopentanoic acid 、 2,5-dihydro-4-[(2-hydroxy-3-methoxy-5-methylphenyl)methyl]-2-methyl-5-oxo-2-furanacetic acid
  参考文献：
  名称：

  The effect of metal ions on the reaction of hydrogen peroxide with Kraft lignin model compounds

  摘要：

  过氧化物漂白受过渡金属和碱土金属的显着影响。隔离不同过渡金属和碱土金属对过氧化物与不同典型木质素结构反应的影响，可以将这些金属离子的正面和负面贡献分开。在这项工作中，五种单体或二聚酚酚木质素模型化合物在缺乏或存在Mn²⁺、Cu²⁺、Fe³⁺和Mg²⁺的碱性过氧化氢中处理。我们跟踪了起始物质的消失以及去甲基化、自由基偶联和草酸形成的进展。过渡金属按Mn²⁺ > Cu²⁺ > Fe³⁺的顺序增加了所有木质素模型化合物与过氧化氢的反应性，这与对过氧化物分解活性的顺序相同，而Mg²⁺稳定了系统。过渡金属的存在增加了体系中所有木质素模型化合物的去甲基化、自由基偶联和草酸形成，并且Mg²⁺的加入则减少了这些反应。总反应程度和去甲氧基化反应的加速改善了过氧化物漂白，但自由基偶联反应的增加可能会影响纸浆的进一步漂白性，而草酸形成的增加可能会导致更大的结垢概率。关键词：木质素、过氧化氢、过氧化物漂白、反应性、化学纸浆、金属化合物、碱处理、过渡金属、脱木质素。

  DOI：

  10.1139/v99-036

文献信息

• Alkaline oxidative degradation of diphenylmethane structures — Activation energy and computational analysis of the reaction mechanism
  作者：Lubo Jurasek、Lívia Krištofová、Yujun Sun、Dimitris S. Argyropoulos

  DOI：10.1139/cjc-79-9-1394

  日期：——

  A diphenylmethane model compound (2,2'-methylenebis[6-methoxy-4-methylphenol]) and residual kraft lignin were treated with alkaline hydrogen peroxide. Kinetic data for the disappearance of the model and the diphenylmethane structures in the residual lignin was collected. The activation energies for the degradation were found to be similar (54 +/- 11 kJ mol(-1) for the model and 58 +/- 5 kJ mol(-1) for the residual lignin). A comparison of the activation energies with the data of a previous study on a biphenyl model compound (3,3'-dimethoxy-5,5'-dimethyl-[1,1'-biphenyl]-2,2'-diol) showed a substantially higher activation energy for the degradation of the latter. Pathways for the degradation of 2,2'-methylenebis[6-methoxy-4-methylphenol] were proposed and the intermediates subjected to computational analysis using a semiempirical method (PM3). The results suggest that initially a common pathway exists, resulting in 2-[2-hydroxy-3-methoxy-5-methyl-phenylmethyl]-4-methyl-2,4-hexadienedioic acid. Then the pathway branches into three, resulting in three major degradation products. The main driving force of the reactions is the formation of radical sites after reaction with hydroxyl radicals and subsequent radical coupling with perhydroxyl radicals to form peroxides. All the reactions on the pathways are exothermic except for the transformations of peroxides into dioxetanes. The dioxetanes cleave exothermically resulting in ring cleavage and fragmentation. The computed data permitted for the rationalization as to why the diphenylmethane structures appear to be more labile than biphenyl structures under alkaline oxidative conditions.
• The effect of metal ions on the reaction of hydrogen peroxide with Kraft lignin model compounds
  作者：Yujun Sun、Michael Fenster、Annie Yu、Richard M Berry、Dimitris S Argyropoulos

  DOI：10.1139/v99-036

  日期：1999.6.1

  Peroxide bleaching is significantly affected by transition and alkaline earth metals. Isolating the effects of different transition and alkaline earth metals on the reactions of peroxide with different representative lignin structures allows the separation of the positive from the negative contributions of these metal ions. In this work, five monomeric or dimeric phenolic lignin model compounds were treated with alkaline hydrogen peroxide in the absence or presence of Mn²⁺, Cu²⁺, Fe³⁺, and Mg²⁺. We followed the disappearance of the starting material and the progress of demethylation, radical coupling and oxalic acid formation were followed. Transition metals increased the reactivities of all the lignin model compounds with hydrogen peroxide in the order Mn²⁺ > Cu²⁺ > Fe³⁺, which is the same as the order of activity toward peroxide decomposition while Mg²⁺ stabilized the system. Demethylation, radical coupling, and oxalic acid formation were all increased by the presence of transition metals in the system and decreased by the addition of Mg²⁺. The acceleration of the total degree of reaction and of the demethoxylation reactions improves peroxide bleaching, but the increase in the radical coupling reactions can affect the further bleachability of pulp while the increase in the formation of oxalic acid could lead to a greater probability of scaling.Key words: lignins, hydrogen peroxide, peroxide bleaching, reactivity, chemical pulps, metal compounds, alkali treatment, transition metals, delignification.

  过氧化物漂白受过渡金属和碱土金属的显着影响。隔离不同过渡金属和碱土金属对过氧化物与不同典型木质素结构反应的影响，可以将这些金属离子的正面和负面贡献分开。在这项工作中，五种单体或二聚酚酚木质素模型化合物在缺乏或存在Mn²⁺、Cu²⁺、Fe³⁺和Mg²⁺的碱性过氧化氢中处理。我们跟踪了起始物质的消失以及去甲基化、自由基偶联和草酸形成的进展。过渡金属按Mn²⁺ > Cu²⁺ > Fe³⁺的顺序增加了所有木质素模型化合物与过氧化氢的反应性，这与对过氧化物分解活性的顺序相同，而Mg²⁺稳定了系统。过渡金属的存在增加了体系中所有木质素模型化合物的去甲基化、自由基偶联和草酸形成，并且Mg²⁺的加入则减少了这些反应。总反应程度和去甲氧基化反应的加速改善了过氧化物漂白，但自由基偶联反应的增加可能会影响纸浆的进一步漂白性，而草酸形成的增加可能会导致更大的结垢概率。关键词：木质素、过氧化氢、过氧化物漂白、反应性、化学纸浆、金属化合物、碱处理、过渡金属、脱木质素。