INVESTIGADORES
SAUX Clara
congresos y reuniones científicas
Título:
Styrene partial oxidation over oxidized and reduced Co-ZSM-5
Autor/es:
S. C. CAGLIERI, L.B. PIERELLA, C. SAUX
Reunión:
Encuentro; 20th North American Meeting; 2007
Resumen:
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The catalytic behaviour of Co-HZSM-5
materials was reported in terms of styrene conversion and products selectivity
at 7 h of reaction time (Table 1).
Table
1. Effect Styrene/H2O2 molar ratio on
the styrene conversion and products selectivity over oxidized and reduced Co-
HZSM-5 zeolites.
Catalyst
Styrene Conversion
(mol %)
Benzaldehyde Selectivity
(mol %)
Styrene Oxide
Selectivity
(mol %)
Other Selectivity (mol %)
Acidity
FTIR
aB/L
HZSM-5 R: 1.7
17.21
88.72
11.28
-
6.41208
Co-HZSM-5 oxidized R:1.7
26.7
89.39
7.14
3.47
0.6286
Co-HZSM-5 Oxidized R: 0.9
19.82
81.10
14.94
3.96
0.6286
Co-HZSM-5 Reduced R: 1.7
23.61
79.25
16.01
4.74
0.9961
aB/L:Brönsted/Lewis
ratio calculated by FTIR of pyridine (mmol/g)retained at 400°C;10-4 Torr
The results reported in Table 1 show an increment of styrene oxide
selectivity and diminution of benzaldehyde selectivity when styrene/H2O2
molar ratio decrease from 1.7 to 0.9 over oxidized zeolite. The benzoic acid (other
selectivity, Table 1) is the benzaldehyde oxidation product and the amount of this
by-product was very low. The benzaldehyde selectivity was superior in the
oxidized zeolite and the styrene oxide selectivity was superior over reduced
zeolite at R: 1.7. The major styrene conversion was observed at R: 1.7 over
oxidized zeolite. The minor styrene conversion was observed at R: 1.7 over HZSM-5. The major presence
Brönsted sites do not help the oxidation reaction, because the results reported
an increment of styrene conversion when Brönsted sites decrease.
