Author/Authors :
Otero Are?n، نويسنده , , C. and Rodr??guez Delgado، نويسنده , , M. and Manoilova، نويسنده , , O.V. and Turnes Palomino، نويسنده , , G. and Tsyganenko، نويسنده , , A.A. and Garrone، نويسنده , , E.، نويسنده ,
Abstract :
Carbon monoxide adsorbed at a low-temperature on the zeolite Li-ZSM-5 forms Li+⋯CO and Li+⋯(CO)2 species characterized by C–O stretching bands at 2195 and 2187 cm−1, respectively. These C-bonded carbonyls are in a temperature-dependent equilibrium with Li+⋯OC and CO⋯Li+⋯CO species having O-bonded CO. By means of variable-temperature FTIR spectroscopy, the enthalpy change involved in the corresponding isomerization process was found to be ΔH°=7.8 kJ mol−1 for the monocarbonyl and ΔH°=5.1 kJ mol−1 for the dicarbonyl. Therefore, although C-bonded species were always found to show a higher cation–CO interaction energy than O-bonded species, the difference is smaller in the case of dicarbonyls.
