Res. Chem. Intermed.
, Vol. 34, Nos 8–9, pp. 871–880 (2008)
Koninklijke Brill NV, Leiden, 2008.
Also available online - www.brill.nl/rci
Styrene epoxidation over a SBA-15-supported Mn(III)
SUJANDI and SANG-EON PARK
Laboratory of Nano-Green Catalysis and Nano Center for Fine Chemicals Fusion Technology,
Department of Chemistry, Inha University, Incheon 402-751, South Korea
Received 22 May 2007; accepted 29 August 2007
Abstract—2,4-Di-tert-butyl-6-((E)-(propylimino)methyl)phenol as a Schiff-base ligand was immobi-
lized onto an amino-functionalized SBA-15 through the reaction between di-tert-butyl-salicylaldahyde
and the tethered amino group. The Mn(III) metal complex of the immobilized Schiff-base ligand was
proven to be an active catalyst for the epoxidation of styrene with tert-butyl hydroperoxide as a termi-
nal oxidant. The catalysts behaved as an oxidation catalyst in the epoxidation and could be used many
times without structural degradation, leaching of active manganese species and signiﬁcant activity
loss. It has been concluded that the reversible redox cycles of the metal center play a key role during
the epoxidation reaction, as well as in the reusability of the catalysts.
Keywords: Schiff base; Mn(III); SBA-15; epoxidation; styrene.
The discovery of ordered mesoporous silica materials opened many new possibili-
ties for applications in the ﬁeld of heterogeneous catalysis, adsorption and separa-
tion due to their large, well-deﬁned pore sizes and high surface areas [1–7]. Selec-
tive oxidation of hydrocarbons, especially oleﬁns epoxidation, has attracted much
attention in recent years since the epoxides are important as synthetic intermediates
for many ﬁne chemicals and pharmaceuticals. Hence, for this purpose, immobi-
lization of metallic cations and metallic complexes which have catalytic activities
in homogeneous systems onto high surface area materials like ordered mesoporous
silica has been widely applied. The immobilization onto the surfaces offered advan-
tages of combination of high catalytic activity, selectivity and stability with easier
separation of the catalysts from the reaction media [5–9].
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