神东煤镜质组结构模型红外光谱的量子化学计算(英文)

IR Spectrum Simulation of Molecular Structure Model of Shendong Coal Vitrinite by Using Quantum Chemistry Method

为了煤的洁净、高效和高附加值利用,需要从分子水平上了解煤的结构。在文献[5]中,作者以元素分析和13 C核磁共振为依据构建了神东煤镜质组(SV)的结构模型,所建模型的13 CNMR模拟计算结果能很好的和实验结果比对,为了进一步验证该模型的准确性,以半经验量子化学计算方法VAMP对SV模型结构的红外谱进行了计算。结果显示模拟计算得到的红外谱图与实验谱图相比峰形相似,但整个计算谱明显偏向高波数区域。经过对相关模型化合物的红外谱进行计算,其原因是半经验方法计算所得官能团结构的振动频率均高于实验测试结果。依此对SV结构模型的红外模拟谱进行修正,修正后实验和模拟谱图能很好地吻合,这进一步证实SV结构模型可以真实的反映神东煤镜质组的结构组成特点。

The structure of coal needs to be understood from a molecular point of view for clean, effective and high value-added utilization of coal. In the literature[5], molecular structure model of Shendong coal vitrinite （SV） was established by the authors on the basis of experimental results of ultimate analysis and 13 C NMR , and the calculated 13 C NMR spectrum of SV model was consistent with the experimental spectrum. In order to further verify the accuracy of SV structure model established by the authors, the infrared spectrum of SV structure model was calculated using quantum chemistry semi-empirical VAMP in this thesis. The results showed that the peak shape of calculated IR spectrum of SV structure model was similar to the experiment＇s, but the wave number of calculated IR spectrum was obviously higher than that of experimental spectrum. Ac- cording to the calculated results for model compounds by using the same method, calculated vibrational fre- quency was higher than that of experiment for the same functional groups. Hence, the calculated IR spectrum should be corrected. After correction the calculated IR spectrum of SV structure model matched well with the experimental spectrum. In other words, the SV structure model can truly reflect the structure characteristics of SV.