Abstract
The condensation products of glucose and 15N-glycine, and xylose and 15N-ammonium sulfate were prepared in order to clarify the origin and the formation of nitrogen in coal by using solid-state 15N NMR. The mixtures were heat-treated in water at 180°C for 50h, and the insoluble products were compressed (100kgf/cm3) at 300 or 400°C for 25 h in He atmosphere (50kgf/cm2). The obtained solid materials were crushed and washed by tetrahydrofuran. Solid-state 13C NMR spectra were measured for the condensation products, and after the thermal decomposition at 180°C, glucose or xylose structures were disappered and the spectra were similar to those of coal, indicating the structural similarities between the condensates and coal. In the case of the mixture of glucose and 15N-glycine, glucose underwent condensation reaction, and 15N-glycine was incorporated in the condensation sturucture during the process of glucose condensation. Nitrogen became incorporated to the condensates mainly in the form of amide at first, and later converted to the form of pyrrole and pyridine by cyclization and aromatization. The process also occurred in the case of the mixture of xylose and 15N-ammonium sulfate. It was considered that the changes of nitrogen functionality of the condensation products in this study are similar to that of coal during coalification.
