Graphite carbon nanotubes from

Wang et al. [102] prepared carbon nanotubes through a reaction of tetrachloroethylene, C2CI4 with potassium at 200"C- in the presence of Au/Fe catalyst. Jiang et al. [103] have reported on the formation of multiwalled carbon nanotubes from hexachlorobenzene and potassium at 350°C in the presence of a Co/Ni catalyst. The authors claimed their reaction temperature to be the lowest record for nanotube production [103]. However, by cross-checking the older literature [4], this claim was, apparently, not correct. A similar reaction of hexchalorobenzene with sodium did not produce nanotubes, but graphite only [93]. 

K. Uchida, M. Yumura, S. Ohshima, Y. Kuriki and F. Ikazaki, Process of isolating carbon nanotubes from a mixture containing carbon nanotubes and graphite particles, US Patent 5,560,898, October 1,1996. 

A two-dimensional sheet-like starting material can be either rolled or sealed at opposing edges to yield tnbe-shaped structures. Such processes have been noted in the formation of carbon nanotubes from graphite but most of the examples concern lipid-like componnds." ... 

Figure A. 11a shows a schematic image of the atomic structure of graphite plane - graphene, and shows how from it can be obtained the nanotube. The nanotube is fold up with the vector connecting two atoms on a graphite sheet. The cylinder is obtained by folding this sheet so that were combined the beginning and end of the vector. That is, to obtain a carbon nanotube from a graphene sheet, it should turn so that the lattice vector R has a circumference of the nanotube in Fig. A. 11b. This vector can be expressed in terms of the basis vectors of the elementary cell gra-...

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