Kinetics and Mechanism for Acetone Hydrogenation by Ru/Carbon

Tuesday, November 9, 2010: 10:15 AM
Grand Ballroom F (Marriott Downtown)
Mohit Bhatia, Adriaan van Heiningen, G. Peter van Walsum and M. Clayton Wheeler, Chemical and Biological Engineering, University of Maine, Orono, ME

Biomass as a source of energy and chemicals has gained importance due to the decreasing oil reserves, fluctuating oil prices and environmental concerns. Ethanol is now used as a blend in conventional transportation fuels, however Ethanol energy density (29.84 MJ/Kg) is quite low compared to conventional gasoline (46.53 MJ/Kg). This reduces overall energy density of ethanol blend gasoline. Alcohols such as Propanol (33.6 MJ/Kg) and Butanol (37.3 MJ/Kg) have higher energy densities and can be used as bends in conventional transportation fuels. Production of these higher alcohol liquid fuels via acidogenic digestion and chemical upgrading of industrial biomass streams offers many advantages over sterile fermentation processes such as lower capital cost, no need for sterility or genetically modified organisms, and ability to produce a variety of chemicals such as carboxylic acids, ketones, esters, and alcohols. Carboxylate salts formed during acidogenic digestion of biomass can be thermally-converted to ketones. The ketones can then be hydrogenated to form higher mixed alcohols. In the current work, the activity of ruthenium supported on activated carbon for hydrogenating ketones is explored using acetone as a model compound. A simple kinetic model which involves the effects of temperature, H2 pressure, and acetone concentration will be presented. Also, results will be discussed which show that the reaction pathway involves an enol intermediate and qualitatively explains an enhancement in the reaction rate by water as well as the product isopropanol.

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