INVESTIGADORES
SAUX Clara
congresos y reuniones científicas
Título:
THE EFFECT OF MOLAR RATIO SUBSTRATE/OXIDANT IN THE CATALYTIC OXIDATION OF STYRENE WITH H2O2
Autor/es:
CANDELARIA LEAL MARCHENA, CLARA SAUX AND LILIANA B. PIERELLA
Reunión:
Workshop; 1st Argentinean Workshop in Environmental Science; 2009
Resumen:
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The influence of substrate/oxidant
ratio for partial
oxidation of styrene towards
benzaldehyde and other products with hydrogen
peroxide as oxidant on
pentasyl microporous zeolite modified with chromium (Cr-ZSM-5),
was studied.
The MFI zeolites,
were obtained by hydrothermal crystallization in the Na2O-Al2O3-SiO2
system. Cr was incorporated to the matrix (NH4+-ZSM-5) by
wetness impregnation technique followed by post-thermal treatments at 500°C (N2
at 10 ml/min and muffle).
The analyses
performed by Atomic Absorption revealed that a 3.0 Cr wt% was effectively
incorporated in the samples. XRD and
FTIR on the fingerprint zone showed a 98% and 97% of crystallinity. Structure
and orthorhombic symmetry were confirmed.
The reaction test were carried out at 60 ºC
varying styrene to H2O2 molar ratio (between 0.45 and
3.2) at different reaction time (1, 3, 5 and 7 h), over 0.2 g of the catalyst
and acetonitrile as solvent. The products were analyzed by GC-Mass
spectrometry.
As can see on figure,
styrene conversion shows an increment when the styrene/H2O2 diminishes.
The benzaldehyde selectivity has the same behavior. This performance could be associated with the decrease
of the oxidant agent in the reaction medium. Benzaldehyde was the main product,
even though others could still be found, such as styrene oxide,
phenylacetaldehyde, 1-phenyl, 1,2-ethanediol and benzoic acid.