Fullerene Black: Relationship between Catalytic Activity in n-alkanes Dehydrocyclization and Reactivity in Oxidation, Bromination and Hydrogenolysis

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>

Methane Conversion over Vacuum Carbon Black: Influence of Hydrogen

“…Over fullerene black this effect was observed at the molar ratio [CH 4 ] 0 /[H 2 ] 0 = 1 and η = 5 % [9]. In contrast to vacuum carbon black fullerene black is subjected to non-catalytic destructive hydrogenolysis [11]. These facts substantiate our hypothesis on hydrogenation of pyrolytic carbon generated on an active component of the catalyst and catalyst active centers blocking as a reasons of inhibition of pyrolytic carbon formation in methane pyrolysis.…”

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

“…558 Kushch et al studied the reactivity of fullerene black in the bromination reaction by bromine. 559 The reaction of bromine with O 3 in dichloromethane at −78 °C produced dibromium pentoxide, which on crystallization from propionitrile produced Br 2 OBr 2 •3EtCN. 560 Bardin et al carried out the reaction of (triethylgermyl)pentafluorobenzene with bromine or Br 2 /AlBr 3 or some other electrophilic reagents with cleavage of the C(aryl)−Ge bond.…”

“…C 70 Br 14 was obtained by bromination of fullerene C 70 in liquid bromine or the solvents 1,1,2,2-tetrachlorethane and carbon disulfide, respectively . Kushch et al studied the reactivity of fullerene black in the bromination reaction by bromine . The reaction of bromine with O 3 in dichloromethane at −78 °C produced dibromium pentoxide, which on crystallization from propionitrile produced Br 2 OBr 2 ·3EtCN .…”