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The catalytic dehydration of glycerol to acrolein is investigated over silica-supported niobia catalysts in a continuous fixed-bed gas-phase reactor. Various supported niobia catalysts are prepared and characterized using surface analysis and spectroscopic methods (XRD, UV–Vis, XPS, N2 adsorption), as well as with ammonia adsorption microcalorimetry. Good results are obtained with initial glycerol conversions of over 70% and with 50–70% selectivity to acrolein. We investigate the influence of changing the catalyst acid strength by varying the niobia content and catalyst calcination temperature. Glycerol conversion and acrolein selectivity depend on the surface acid strength. Catalyst deactivation by coking is also observed, but simple oxidative treatment in air restores the activity of the catalysts completely. [ABSTRACT FROM AUTHOR]

A systematic study of catalytic ethylation of phenol is carried out with ethanol as a function of feed composition, time on stream (TOS), temperature, and catalyst composition over Cu1-xCoxFe2O4 (x=0.0–1.0) ferrospinel system. Phenol ethylation gives 2-ethyl phenol as a major product under the reaction conditions employed, while its selectivity decreases as temperature and Co-content increases. Compositions containing both Cu and Co (0