Fullerene synthesis

Chaur MN, Athans AJ, Echegoyen L (2008) Metallic nitride endohedral fullerenes synthesis and electrochemical properties. Tetrahedron 64 11387-11393... 

V. S. Kuck (eds.), Fullerenes Synthesis, Properties, and Chemistry of Large Carbon Clusters, ACS Symp. Ser. 481, American Chemical Society, Washington, D.C., 1992 H. W. Kroto and D. R. M. Walton (eds.), Fullerenes New Horizons for the Chemistry, Physics, and Astrophysics of Carbon. Cambridge Univ. Press, Cambridge, 1993 H. W. Kroto (ed.), Fullerenes. Pergamon/Elsevier, London, 1993 A. Hirsch, The Chemistry of the Fullerenes. Thieme Verlag, Stuttgart, 1993 H. Aldersley-Williams, The Most Beautiful Molecule Discovery of the Buckyball. Wiley, New York, 1995. 

Wudl, F. In Fullerenes Synthesis, Properties and Chemistry of Large Carbon Clusters ACS Symposium Series 48, 1992, 161-175. 

G. Hammond and V. J. Kuck (Eds.), Fullerenes Synthesis, Properties, and Chemistry of Large Carbon Clusters, ACS Symposium Series 481, American Chemical Society, Washington, DC, 1992. 

This intermediate towards rational fullerene synthesis decomposed violently on scratching with a spatula. The unchlorinated equivalent was stable. 

Several proposals have been put forward to account for the formation of C 0F and the other fullerenes. Before reviewing these proposals, it seems appropriate to consider the key observations about fullerene synthesis, the kinds of carbon clusters possible, their energetics, and the thermodynamic and kinetics of carbon clustering. 

Haufler, R. E. et al. 1991 Carbon arc generation of C60. Mater. Res. Soc. Proc. 206, 627-638. Heath, J. R. 1991 Synthesis of C60 from small carbon clusters a model based on experiment and theory. In Fullerenes synthesis, properties, and chemistry of large carbon clusters (ACS Symp. Ser., no. 481) (ed. G. S. Hammond V. J. Kuck), pp. 1-23. Washington, D.C. American Chemical... 

In light of the mass spectrometric results described above, a rational fullerene synthesis from cyclophyne precursors appears to be within reach. Since superphane 21 [43] and superferrocenophane 22 [44] are established structural precedences, it may well be that reports about a successful synthesis of superphyne 23, an acetylenic isomer of buckmin-sterfullerene, or even a corresponding supermetallophyne are only a short time away. 

All samples were obtained in the setup for fullerene synthesis by the technique described earlier [4-5], Novelty of this technique was that materials were produced in plasma-chemical reactor without air access and they shifted to the chamber for the sample investigation, see Fig. 1. 

The obtained temperature dependencies had shown that the quantity of desorbed hydrogen is increased with increasing of the temperature for all carbon samples (Fig. 2). Maximal hydrogen content (0.92 % wt.) was registered for the soot collected at the outlet surface of the fullerene synthesis chamber. By the method of electron microscopy it was detected that this sample contained 9% of fullerenes and more than 40% of single-wall carbon nanotubes (SWCNT). 

FULLERENE SYNTHESIS IN HELIUM FLOW AT ATMOSPHERIC PRESSURE... 

But a wide application of such substances is hampered by their high costs of synthesis and purification. The most popular synthesis methods are the arc-discharge and laser-ablation method which have the disadvantage of either small fullerene yield or small quantity of the fullerene containing soot. Moreover it is necessary to use vacuum technique for maintaining of low pressure of helium for these methods. For the hydrocarbon combustion method it is necessary to use the additional expenses for fullerene purification [1-3], Thus, the search for improved methods of fullerene synthesis is of considerable importance. 

In an earlier publication we showed that fullerene may be synthesized not only under low pressure conditions, but under atmospheric pressure as well [4]. In this work we present the result of fullerene synthesis by the arc discharge method under atmospheric pressure in which currents of different frequencies are applied. 

On the Fig. 1 the graphs of the obtained dependencies are shown. One can see that soot, fullerenes and re-crystallized graphite are formed in all cases, and their yields depend on both current value and current type. Re-crystallized graphite is a byproduct of the fullerene synthesis which decreases the fullerene productivity and efficiency. It was established that the optimal regime of fullerene synthesis occurs at 44 kHz AC and 200 A. Under these conditions, a fullerene production rate of 16mg/min at a fullerene yield of 9% was obtained while the yield of re-crystallized graphite (7%) was minimal. 

Thus, high fullerene yield at 44 kHz may be explained by the occurrence of electron concentration oscillations in the plasma. That such electron concentration oscillations are highly affecting the fullerene synthesis is known. For details see [8],... 

The basic characteristics of devices for fullerene synthesis at atmospheric pressure were investigated. It was observed that the maximum fullerene production rate (16 mg/min) was obtained in arcs fed by AC of 44 kHz and 200 A. Under these conditions the amount of deposited re-crystallized graphite was minimal, and practically all evaporated carbon was transformed into soot containing 9% of fullerenes. 

J. M. Williams, J. R. Ferraro, R. J. Thom, K. D. Carlson, U. Geiser, H. H. Wang, A. M. Kini, and M.-H. Whangbo, Organic Superconductors (Including Fullerenes) Synthesis, Structure, Properties, and Theory, Prentice Hall, Englewood Cliffs, NJ, 1992. 

M. -H. Whangbo, Organic Superconductors (Including Fullerenes) Synthesis, Structure, Properties, and Theory, Prentice Hall, Englewood Cliffs, N.J., 1992. 

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