Pyrolysis of aromatic carboxylic acids : Potential involvement of anhydrides in retrograde reactions in low-rank coal
Pyrolysis of aromatic carboxylic acids : Potential involvement of anhydrides in retrograde reactions in low-rank coal
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DOI：
10.1021/ef9700745
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发表时间：
1997-11
期刊：
影响因子：
5.3
通讯作者：
T. P. Eskay;P. Britt;A. C. Buchanan
中科院分区：
文献类型：
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作者：
T. P. Eskay;P. Britt;A. C. Buchanan
研究了1-(3-羧基苯基)-2-(4-联苯基)乙烷(3)在400℃下，在供氢和非供氢溶剂中的稀释液相热裂解反应，以确定芳香族羧酸脱羧基在低煤阶煤的交联过程中的作用。在该模型化合物的热解过程中，脱羧基是主要的反应途径，脱羧基主要通过酸促进的离子机制进行，不会导致交联。然而，在非给体溶剂中的热解产生了少量的产物，该产物包含在3和代表与脱羧基过程相关的交联键的溶剂之间的新的芳基−芳基键。这些交联产物是通过自由基途径形成的，并且可以通过向热解介质中添加水或四氢呋喃来减少。认为交联剂的生成与酸解过程中酸酐的生成和分解有关。
The pyrolysis of 1-(3-carboxyphenyl)-2-(4-biphenyl)ethane (3) has been studied in the liquid phase at 400 °C neat and diluted in hydrogen-donor and nondonor solvents to determine the role of decarboxylation of aromatic carboxylic acids in the cross-linking processes in low-rank coal. Decarboxylation was the dominant reaction pathway in the pyrolysis of this model compound, and decarboxylation occurred primarily by an acid-promoted ionic mechanism that does not lead to cross-linking. However, pyrolysis in a nondonor solvent produced a small amount of products containing a new aryl−aryl bond between 3 and the solvent that represents the formation of a cross-link associated with the decarboxylation process. These cross-linked products were found to be formed by a free-radical pathway and could be decreased by the addition of H2O or tetralin to the pyrolysis medium. It is proposed that the cross-linked products arise from the formation and subsequent decomposition of anhydrides during the pyrolysis of the aci...