Oxidative dehydrogenation of ethanol to acetaldehyde and ethyl acetate by graphite nanofibers

Three types of graphite nanofibers (GNFs), with varying orientations of the graphene sheets (herringbone, platelet, and ribbon), were used as catalysts for the gas-phase oxidative dehydrogenation of ethanol to acetaldehyde and ethyl acetate in the presence of oxygen. The effects of fiber type, temperature, oxygen concentration, and ethanol concentration on conversion and product ratio were explored. When identical processing conditions were employed, herringbone fibers produced higher conversions of ethanol compared to platelet and ribbon fibers, which yielded similar results to one another. Altering equilibrium conditions by increasing oxygen concentration tended to increase conversion as well as increase the percentage of acetaldehyde produced. Adjusting oxygen concentration had a more significant affect on the platelet and ribbon fibers. Temperature also altered the conversion and product ratios as expected. It is believed that the oxygen groups terminating the prismatic edge sites of the graphene planes are responsible for the catalytic activity in oxidative dehydrogenation reactions such as the one explored here.