Abstract
<p>The reactivity of fullerene black in oxidation (by air oxygen or ions MnO<sub>4</sub><sup>–</sup> or Cr<sub>2</sub>O<sub>7</sub><sup>2–</sup> in solution), bromination (by Br<sub>2</sub> or (C<sub>4</sub>H<sub>9</sub>)<sub>4</sub>NBr<sub>3</sub>) and hydrogenolysis (without hydrogenation catalyst) are studied. The dehydrocyclization of <em>n</em>-alkanes over fullerene black is realized via the monofunctional mechanism, <em>i.e. </em>the dehydrogenation and cyclization stages proceed on the same catalytic center. The addition of alumina to the catalyst transforms dehydrocyclization mechanism to bifunctional one, when fullerene black acts as dehydrogenation agent. Reactivity studies and ESR spectroscopy data for initial and annealed fullerene black show the presence in fullerene black structure of both non-conjugated multiple and dangling bonds. Nonconjugated bonds determine catalytic activity and reactivity of fullerene black. They are localized in amorphous part of fullerene black. Technological aspects of fullerene black as alkanes dehydrocyclization catalyst are discussed.</p>
Highlights
Fullerene black is the main (80–90 wt %) part of condensed product of electric arc graphite vaporization
We have revealed that completeness and other parameters of oxidation are determined by the rate of air supply and by the thickness of fullerene black layer
Hydrogen and oxygen are probably present as non-removable water, because water was detected in absolute methanol after washing of fullerene black evacuated at 100°C for 10 h
Summary
Fullerene black is the main (80–90 wt %) part of condensed product of electric arc graphite vaporization. In the vicinity of which there is no adsorbed oxygen molecules, give rise to the ESR signal of the sample. Organic solvents (benzene, toluene, oil, chlorobenzene and tetrahydrofuran) desorb adsorbed oxygen with increase of ESR signal intensity up to initial value.
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