(687b) Preliminary Investigations of the Catalytic Deoxygenation of Fatty Acids

Biobased sources of alkanes and alkenes are limited; such materials, however, would provide the most direct replacements of petroleum-based feedstocks. One possible route to alkanes and alkenes from readily available biomass is the decarboxylation of fatty acids. In this presentation, initial studies of the thermocatalytic conversion of oleic acid will be reported, specifically the decarboxylation of the acid to alkanes and alkenes. The reaction products formed in the presence of zinc oxide, alumina, and the zeolite ZSM-5 are compared those associated with thermal decomposition alone. At temperature below 250° C, thermal decomposition without catalysts shows only limited gaseous products characteristic of pyrolysis reactions. The reaction products formed in the presence of ZSM-5 are typical of catalytic cracking reactions. The products formed from ZnO suggest that two reactions proceed in parallel at these conditions. The presence of carbon dioxide is consistent with catalytic decarboxylation. The liquid phase products include significant production of zinc oleate via the fusion reaction. As the temperature is increased to 400°C, reactions over ZnO shift away from forming the metal soap to the production of hydrocarbons. The reaction of oleic acid over alumina at 400°C appears to involve reactions in series. Initially decarboxylation of the fatty acid occurs yielding heavier hydrocarbons. With longer reaction times, intermediate range (C8 ? C10) hydrocarbons have been identified.