The adsorption and oxidation of the simple olefins ethylene, propylene and n-butenes on the surface of vanadia-titania and PdCl2-containing vanadia titania have been investigated by FT-IR spectroscopy. Two oxidation paths have been observed on vanadia-titania, one producing species functionalized at C2 (acetaldehyde from ethylene, acetone from propylene, methyl-ethyl-ketone and acetic acid from n-butenes), and the other giving compounds functionalized at C1 and C1/C4 (acrolein and acrylic acid from propylene, butadiene, furan and maleic anhydride from n-butenes). On PdCl2-containing vanadia-titania olefins are oxidized much faster to carbonylic compounds, that are also more stable with respect to overoxidation, without the intermediacy of alkoxide species. A mechanism involving the formation of Pdalkylidene species and their oxidation by V5+ is proposed. © 1992.
An infrared spectroscopic study of the interaction of olefins on vanadia-titania and PdCl2-vanadia-titania selective oxidation catalysts
BUSCA, GUIDO;
1992-01-01
Abstract
The adsorption and oxidation of the simple olefins ethylene, propylene and n-butenes on the surface of vanadia-titania and PdCl2-containing vanadia titania have been investigated by FT-IR spectroscopy. Two oxidation paths have been observed on vanadia-titania, one producing species functionalized at C2 (acetaldehyde from ethylene, acetone from propylene, methyl-ethyl-ketone and acetic acid from n-butenes), and the other giving compounds functionalized at C1 and C1/C4 (acrolein and acrylic acid from propylene, butadiene, furan and maleic anhydride from n-butenes). On PdCl2-containing vanadia-titania olefins are oxidized much faster to carbonylic compounds, that are also more stable with respect to overoxidation, without the intermediacy of alkoxide species. A mechanism involving the formation of Pdalkylidene species and their oxidation by V5+ is proposed. © 1992.
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