Evaluation of Macromolecular Structure of a Brown Coal by Means of Oxidative Degradation in Aqueous Phase
Evaluation of Macromolecular Structure of a Brown Coal by Means of Oxidative Degradation in Aqueous Phase
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DOI：
10.1021/ef9800922
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发表时间：
1999
期刊：
影响因子：
5.3
通讯作者：
J. Hayashi;S. Aizawa;H. Kumagai;T. Chiba;Tadashi Yoshida;S. Morooka
中科院分区：
文献类型：
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作者：
J. Hayashi;S. Aizawa;H. Kumagai;T. Chiba;Tadashi Yoshida;S. Morooka
将酸洗的Morwell褐煤在85 °C下在封闭系统中在0.5N Na 2CO 3水溶液中氧化，氧气通过该封闭系统鼓泡。氧化过程需要1 - 12小时，每克煤消耗1.8 - 5.8 mmol O2。产物的分析表明，芳香族碳被选择性地氧化成羧基的残留固体（氧化煤），水溶性的非芳香族酸，和二氧化碳，而脂肪族碳是最低限度地参与反应。考虑到煤由两个主要的结构元素，芳香族簇（单或稠合的芳香环与外围基团）和簇间桥（烷基和醚连接簇），它的结论是，氧化转化成周边羧基的相邻簇上的桥键的芳香族碳，也转化成非芳香族酸或二氧化碳的其他芳香族碳。根据煤的氧化机理，即煤的大分子网络被分解，
Acid-washed Morwell brown coal was oxidized at 85 °C in a 0.5 N Na2CO3 aqueous solution in a closed system, through which oxygen gas was bubbled. The oxidation took 1−12 h and consumed 1.8−5.8 mmol of O2 per gram of the coal. Analyses of the products revealed that aromatic carbon was selectively oxidized into carboxyls in the residual solid (oxidized coal), water-soluble nonaromatic acids, and carbon dioxide, while aliphatic carbon was minimally involved in the reaction. Considering that the coal consists of two major structural elements, aromatic clusters (mono- or fused aromatic rings with peripheral groups) and intercluster bridges (alkyl groups and ethers connecting clusters), it was concluded that the oxidation converted aromatic carbons bonded to bridges into peripheral carboxyl groups on the neighboring clusters and also converted the other aromatic carbons into nonaromatic acids or carbon dioxide. According to the mechanism of the oxidation, which decomposed the macromolecular network of the coal-...