OXIDATIVE WEATHERING OF ILLINOIS NO-6 COAL
OXIDATIVE WEATHERING OF ILLINOIS NO-6 COAL
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DOI：
10.1016/0016-2361(83)90028-5
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发表时间：
1983-01-01
期刊：
影响因子：
7.4
通讯作者：
ISAACS, J
中科院分区：
文献类型：
--
作者：
LIOTTA, R;BRONS, G;ISAACS, J
将新开采的伊利诺斯州6号烟煤（蒙特利矿1号）在环境条件下暴露于大气氧导致缓慢的氧化反应，该反应似乎在两个月内完成，以产生比新鲜煤多26%的有机结合氧的氧化煤产物。进行氧官能团分析以确定反应之前、期间和之后煤的羧酸、羟基和醚基含量。红外分析显示没有羰基生成;然而，正在生成醚官能团。采用同位素标记的甲基（C-13和氘）的O-甲基化反应被用来识别和量化风化煤样品中的O-H和CO2 H位点。发现这些酸性基团不是氧化风化的产物。基本上所有化学结合的氧最终形成醚键。在对这种煤的相关研究中，在氧化的早期阶段检测到氢过氧化物作为瞬态中间体。提出了一种机制，其中涉及在温和的温度下同时形成的氢过氧化物和碳自由基，经历自由基置换生产的醚产品直接。溶剂溶胀研究表明，这些醚作为交联剂在煤的结构。风化作用导致的高度交联的煤结构是破坏这种烟煤塑性的原因。
The exposure of freshly-mined Illinois No.6 bituminous coal (Monterey Mine No.1) to atmospheric oxygen at ambient conditions resulted in a slow oxidation reaction which appeared to be complete within two months to produce an oxidized coal product with ≈26% more organically bound oxygen than the fresh coal. An oxygen functional group analysis was performed to determine the carboxylic acid, hydroxyl and ether group content of the coal before, during and after the reaction. Infrared analysis showed no carbonyl production; however, ether functionality was being produced. O-methylation reactions which employed isotopically labelled methyl groups (both C-13 and deuterium) were used to identify and quantify O-H and CO2H sites in the weathering coal samples. It was found that these acidic groups were not the products of oxidative weathering. Essentially all of the chemically incorporated oxygen eventually formed ether linkages. In a related study on this coal, hydroperoxide was detected as a transient intermediate in the early stages of the oxidation. A mechanism is proposed which involves the simultaneous formation under mild temperatures of a hydroperoxide and a carbon radical that undergoes a radical displacement producing the ether product directly. Solvent swelling studies revealed that these ethers act as cross-linking agents in the coal structure. The more highly cross-linked coal structure that resulted from weathering was responsible for the destruction of the plastic properties of this bituminous coal.