SYNTHESIS OF NOVEL NANOCARBONS FROM CARBON PRECURSORS PRERARED BY DEFLUORINATION

本研究的目的是利用全氟有机化合物与碱金属脱氟合成纳米纤维和纳米球等新型纳米碳。该方法的优点是可以在低于200℃的低温下进行反应。制备的产物（碳前驱体）被热处理到更高的温度，以便从前驱体中获得稳定的碳。利用不同种类的全氟化合物，我们成功地合成了具有独特形貌和孔隙度的纳米多孔碳。这些碳基本由非晶结构组成，但在2000℃以上的高温处理中，除了非石墨成分外，还产生了石墨成分。此外，用钠或钾在真空条件下对含脂肪族碳-碳链的五氟辛烷、含芳环的六氟苯和八氟甲苯以及环上含氮原子的五氟吡啶进行脱氟处理，得到纳米多孔碳和纳米纤维。发现它们具有不同的介孔体积和孔径分布。为控制孔径分布，制备sp和sp^2碳纳米复合材料，以辛氟甲苯和五氟辛烷为起始试剂。这些化合物的沸点几乎相同。将两种组分按不同比例混合后，进行除氟处理。结果表明，两种全氟化合物的混合对控制孔径分布是非常有效的。现在我们正在继续收集实验数据。

The purpose of this study is to synthesis novel nanocarbons such as nanofibers and nanospheres by use of defluroination of perfluoroorganic compounds with alkali metals. This procedure has an advantage in which the reaction can progress at low temperatures less than 200℃. The as-prepared products(carbon precursors) were heat-treated up to higher temperatures in order to obtain stable carbons from the precursors. As a result we succeeded in synthesis of nanoporous carbons with characteristic morphology and unique porosity by using various kinds of perfluorocompounds. These carbons are consisted basically of amorphous structure, but the treatment at higher temperatures than 2000℃ brought about not only the non-graphitic constituents, but also the graphitic components. In addition, when pentafluorooctane with an aliphatic C-C chain, hexafluorobenzene and octafluorotoluene containing an aromatic ring and also pentafluoropyridine having a nitrogen atom in a ring were defluorinated under vacuum with sodium or potassium, nanoporous carbons and nanofibers were obtained. It was found that they have different mesopores volume and pore size distributions. In order to control the pore size distribution and to obtain nano-composites made up of sp and sp^2 carbons, octafluorotoluene and pentafluorooctane were used as starting reagents. These compounds have nearly same boiling point. The mixture of both components with various ratios was defluorinated and treated as the same manner. As a result it was elucidated that the mixing of both perfluorocompounds is very effective for the control of the pore size distribution. Now we are continuing accumulation of the data on this experiment.