INTEC   05402
INSTITUTO DE DESARROLLO TECNOLOGICO PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Liquid-phase FTIR study of the acylation capacity of supported phospho-tungstic Wells-Dawson heteropoly-acid
Autor/es:
S.E. COLLINS, S.R. MATKOVIC, A.L. BONIVARDI, L.E. BRIAND
Lugar:
, Rostock-Warnemünde, Alemania
Reunión:
Congreso; III International Operando Congress; 2009
Resumen:
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Heteropoly-anions [XyMxOm]n-
are composed by a close-packed framework of metal-oxygen octahedrons, M-O (M =
Mo6+, W6+, V5+) surrounding a central atom, X
(Si4+, P5+, etc) [1]. Nowadays, many research efforts are
devoted to investigate both Keggin [XM12O40]3-
and Wells-Dawson-type [X2M18O62]6-
anions due to their promising application as catalytic materials [2, 3]. The
free acid form of the heteropoly-anions, i.e. Keggin H3XM12O40
and Wells-Dawson H8X2M18O62 type
compounds, are solid super-acids since their acid strength is greater than 100%
H2SO4. Therefore, many heteropolyacids are more active
catalysts than conventional organic and inorganic acids in liquid-phase
reaction. The insolubility of the heteropoly-acids in many liquid organic
substances allows an easy separation and reutilization of these catalysts [3,
4].
Undoubtedly, the catalytic processes based on
heteropoly-acids are an outstanding contribution in the development of
environmental benign technologies.
On line with this worldwide trend, our group explores
the catalytic activity of fosfotungstic Wells-Dawson heteropoly-acid in the
Friedel-Crafts acylation of p-isobutylbenzene with acetic anhydride towards
p-isobutylacetophenone. This substance is an intermediate species in ibuprofen
synthesis [5, 6].
Surprisingly, the preliminary results showed that p-isobutylbenzene
was acylated towards 4-isobutylacetophenone and this substance was further
condensed towards a dypnone like compound. Therefore, the present investigation
was conducted in order to explore both the ability of the HPA to catalyze the
Friedel-Crafts acylation and further Aldol condensation of the substituted
acetophenone and further understand the deactivation of the heteropoly acid
during the acylation.