Abstract Aromatic skeleton structure of Naomaohu (NMH) coal was investigated by a step-wise oxidation degradation and XRD, Raman and XPS characterization. Coal was first oxidized with H2O2 to result in breakage of only bridged bonds and side chains, then the oxidation residue was further degraded through controlling alkali-oxygen (A-O) oxidation to avoid ring-open of polyaromatics and the conversion of coal sample exceeded 97.4 wt%. Synchronous fluorescence spectrometry (SFS) analysis of the oxidation products inferred that the aromatic structures in NMH coal mainly involve 1–4 rings compounds, among which single-ring structures are dominant accounting for 54.4 mol%. The results of XRD, Raman and XPS showed that NMH coal has a turbostratic structure, an intermediate state between the amorphous state and graphite, comprised by amorphous carbons and orderly aromatic clusters. The heteroatoms mainly exist in the forms of carbonyl, hydroxyl, pyrrolic nitrogen, mercaptan or thiophenol, thiophene, sulfoxide and sulfone. A simplified model of coal skeleton structure was proposed based on the complementary information from various techniques. Moreover, SFS analysis of A-O oxidation products clearly exhibits the gradual cracking process of polyaromatics, which provides an efficient method for controllable production of benzene carboxylic acids by preventing excessive or incomplete oxidation.

中文翻译：

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通过逐步氧化降解深入了解低阶煤的芳环结构

摘要 通过逐步氧化降解和XRD、Raman 和XPS 表征研究了Naomaohu (NMH) 煤的芳族骨架结构。煤首先用 H2O2 氧化，仅导致桥键和侧链断裂，然后通过控制碱-氧 (AO) 氧化进一步降解氧化残渣，避免聚芳烃开环，煤样转化率超过 97.4 wt %。氧化产物的同步荧光光谱（SFS）分析推断，NMH煤中的芳族结构主要涉及1-4个环化合物，其中单环结构占主导地位，占54.4 mol%。XRD、Raman 和 XPS 结果表明 NMH 煤具有湍层结构，介于非晶态和石墨之间的中间态，由无定形碳和有序的芳香族簇组成。杂原子主要以羰基、羟基、吡咯氮、硫醇或苯硫酚、噻吩、亚砜和砜的形式存在。基于各种技术的补充信息，提出了煤骨架结构的简化模型。此外，AO 氧化产物的 SFS 分析清楚地显示了多环芳烃的逐渐裂解过程，这为通过防止过度或不完全氧化来可控生产苯羧酸提供了一种有效的方法。基于各种技术的补充信息，提出了煤骨架结构的简化模型。此外，AO 氧化产物的 SFS 分析清楚地显示了多环芳烃的逐渐裂解过程，这为通过防止过度或不完全氧化来可控生产苯羧酸提供了一种有效的方法。基于各种技术的补充信息，提出了煤骨架结构的简化模型。此外，AO 氧化产物的 SFS 分析清楚地显示了多环芳烃的逐渐裂解过程，这为通过防止过度或不完全氧化来可控生产苯羧酸提供了一种有效的方法。