Formation mechanism of fullerenes

富勒烯的形成机理

基本信息

批准号：
11165222
负责人：
OSAWA Eiji
金额：
$ 12.03万
依托单位：
Toyohashi University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11165222/
关键词：
Mechanism of fullerene formation Natural fullerenes Coal Carbon black C60 TEM Shock wave peaceful use of explosives C_<60>生成機構 3次元螺旋ナノ粒子多層フラーレン煤電子線照射生成自由エネルギー天然カーボンナノチューブ天然カーボンナノ粒子 HPLC

项目摘要

Mechanism of fullerene formation is one of the most difficult problems in fullerene science but has been urgently needed in order to develop industrially favorable synthesis of C60, which is actually a critical obstacle to the emergence of applications of fullerene carbons. During the tenure of this grant, we clarified the mechanism and proposed two entirely new and promising methods of the preparation of C60.Our work is motivated by a novel coal sample arrived from Yunnan Province, China, that contains surprisingly high concentration of C60/C70 (an initial concentration immediately after excavation estimated to be 0.3%). We found three pieces of evidence that indicate that this particular coal has been exposed to shock wave. The strongest evidence is high abundance of the primary particles of soot with extremely small diameter (ca 10 nm in diameters). Noting the fact that the purest and the most readily available soot is commercial carbon black, we thereupon used carbon black in our s … More ubsequent study. Whereas carbon black did not contain measurable amounts of C60, we observed that the primary particles of carbon blacks are cleanly converted to onion-like multi-shell fullerenes upon irradiation with focused electron beam (a substitute of shock wave). Careful examination of this transformation in TEM revealed intervention of spiral particles as the intermediate. Furthermore, we also found that onion changes into spirals. We assumed that the spiral TEM images represent 3D spiroidal particles close in shape with onions. Chemical as well as numerical models were conceived and generated. These works eventually led us to construct a consistent mechanism of fullerene formation consisting of spiral growth of spiroids and the stabilization of spiroid particles into onions by reversible multiple bond cleavage/intershell valence isomerization reactions/multiple bond closure. Success of this mechanism to elucidate the origin of unique configuration of onions encouraged us to conceive a new method of C60 production that uses the production line of carbon black.Another new method of C60 production is simply to expose carbon to shock heating. If shock wave is generated by detonation of explosives and coal is carbon materials, the production of C60 may be carried out on the coal mine site. The method is cost effective, contributes to environmental problem by reducing the CO2 emission by burning coal as the fuel, and also promotes the use of explosives for peaceful purposes. There are already some examples previously reported in the literature that indicates that somewhat shock wave will generate fullerenes in stead of diamond under some conditions. For example, in a shock tube experiment, 300 ppm of C60 was formed when benzene was subjected to detonative shock. A few careful preliminary experiments will be needed to verify the present proposal. Less

富勒烯的形成机理是富勒烯科学中最困难的问题之一，但为了开发工业上有利的C60合成方法，这实际上是富勒烯碳应用的一个关键障碍。，我们阐明了这一机制，并提出了两种全新且有前途的 C60 制备方法。我们的工作受到来自中国云南省的一种新型煤样的推动，该煤样含有令人惊讶的高浓度 C60/C70 （挖掘后的初始浓度估计为 0.3%），我们发现了三个证据，表明这种特殊的煤已经受到冲击波的影响，最有力的证据是大量直径极小的烟灰初级颗粒（直径约 10 nm）。注意到最纯净且最容易获得的烟灰是商业炭黑，因此我们在后续研究中使用了炭黑。 C60，我们观察到，在聚焦电子束（冲击波的替代品）照射下，炭黑的初级颗粒完全转化为洋葱状多壳富勒烯。在 TEM 中仔细检查这种转变，发现螺旋颗粒的介入。此外，我们还发现洋葱会变成螺旋状。我们假设螺旋 TEM 图像代表与洋葱形状接近的 3D 螺旋粒子。这些工作最终引导我们进行了构想和生成。构建了一种一致的富勒烯形成机制，包括螺旋体的螺旋生长和通过可逆的多键断裂/壳间价异构化反应/多键闭合将螺旋体颗粒稳定化为洋葱，该机制的成功阐明了洋葱独特构型的起源。鼓励我们构思一种使用炭黑生产线生产 C60 的新方法。C60 生产的另一种新方法是将碳暴露于冲击加热中。波是由炸药爆炸产生的，而煤是碳材料，可以在煤矿现场进行C60的生产，该方法具有成本效益，通过燃烧煤作为燃料来减少CO2排放，有助于解决环境问题。也促进了将爆炸物用于和平目的。文献中已经有一些例子表明，在某些条件下，冲击波会产生富勒烯而不是金刚石，例如，在激波管实验中，300 ppm的。 C60 是在苯受到爆炸冲击时形成的，需要进行一些仔细的初步实验来验证目前的建议。