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FT-IR studies on the selective oxidation and combustion of light hydrocarbons at metal oxides surfaces. Part 2. Propane and propene oxidation on Co3O4
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Chemistry of olefins at metal oxide surfaces: a tool for surface science investigation of oxide catalysts
No full textAn infrared spectroscopic study of the interaction of olefins on vanadia-titania and PdCl2-vanadia-titania selective oxidation catalysts
No full textThe 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
Low-Temperature Oxidation of Light Paraffins and Olefins at Solid Surfaces: Ft-Ir Studies
No full textThe interaction of methane, ethane and ethylene, and of some C1 and C2 oxygenates on the surface of model oxidation catalysts (Co3O4 and Pd-TiO2) has been investigated by FT-IR spectroscopy. Oxidation of alkanes is observed on Co3O4 starting from near 673 K, and near 373 K on Pd-TiO2. Olefins are oxidized already at room temperatures. Attempts are made to propose a mechanism for these reactions. © 1993
The acidity of aluminas and silica-aluminas: catalytic activity in the conversion of ethanol
No full textThe properties of a number of commercial aluminas and silica-alumina have been characterized by XRD, TEM, Surface area and porosity analysis, skeletal IR and Raman spectroscopies, IR studies of adsorbed probe molecules (hydroxy groups, pyridine, CO, CO2). The catalytic activity of these materials in the dehydration of ethanol to ethylene and diethylether has been studied in a flow reactor as well as in an IR cell. The catalytic activity data have been discussed in relation to the surface chacarterization data. This allowed us to crytically discuss the most popular models for the surface sites of alumina and silica-alumina
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