1
40
G.S. Machado et al. / Journal of Catalysis 274 (2010) 130–141
the product yields obtained in the absence of the scavenger. Cyclo-
hexanone production was strongly affected in the presence of tert-
butyl alcohol, which has larger affinity for the active catalytic spe-
cies than the cyclohexane radicals. The sharp decrease in total
product yield in the case of cyclohexane oxidation catalyzed by Fe-
Por–ZHN in the presence of the radical scavenger is strong evidence
that the oxidation reaction mechanism follows a radical route
various immobilized catalysts onto different inorganic supports a
very interesting approach for the design of a new and wide range
of catalysts.
Acknowledgments
The authors thank Conselho Nacional de Desenvolvimento
Científico e Tecnológico (CNPq), Coordenação de Aperfeiçoamento
de Pessoal de Nível Superior (CAPES), Fundação Araucária, Fun-
dação da Universidade Federal do Paraná (FUNPAR), and Universid-
ade Federal do Paraná (UFPR) for financial support. The authors are
also grateful to Centro de Microscopia Eletrônica da UFPR for the
TEM analyses. G.S. Machado thanks CAPES for a master grant.
[
42,59]. Besides that, in the cyclohexane oxidation reaction per-
formed in dichloromethane/acetonitrile solvent mixture, a small
peak in the retention time of 1.77 was also observed in GC analysis
that was identified as chloro-cyclohexane product. In a catalysis
carried only in pure acetonitrile, this peak was not observed. The
presence of the chlorinated product also suggests that a radicalar
reaction mechanism is occurring [64].
In conclusion, the obtained results show that the effective com-
bination between the irregular surface of the ZHN support and the
immobilized FePor creates a singular environment that provides
new selectivity for porphyrin systems in the case of the catalytic
oxidation of cyclohexane. Moreover, the reaction mechanism prob-
ably consists of a radical route.
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