Gamma alumina (?-Al2O3) is widely used in industry to catalyze the dehydration of alcohols to produce alkenes. To complete our understanding of the entire catalytic cycle, the sites where alcohols are initially bound to the surfaces of ?-Al2O3 must be thoroughly investigated. In this study the adsorption of 1-13C enriched ethanol onto the surface of ?-Al2O3 was investigated by 1H-13C and 1H-27Al cross-polarized magic-angle spinnig (CPMAS) solid-state nuclear magnetic resonance (NMR), and temperature programmed desorption-inverse gas chromatography (TPD-IGC). The ?-Al2O3 samples were pretreated in an evacuated system from 100�C to 500�C in increments of 100�C followed by gas phase dosing with ethanol at 100�C. 1H-13C CPMAS results indicate that the site of ethanol absorption to the surface changes as a function of pretreatment temperature. 1H-27Al CPMAS of the samples showed changes in the surface configurations over the same temperature range, most likely due to dehydroxylation. TPD-IGC data collected for the ?-Al2O3 pretreated at 200�C shows ethanol desorbing from the surface at three different temperatures.

Solid-state NMR study of ethanol adsorbed onto the surface of gamma alumina

245th National Meeting (2013)

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