(297b) Catalytic Decarboxylation of Palmitic Acid in High Temperature Water

Fatty acids are available from renewable resources such as vegetable oils, nut oils, and microalgae. Decarboxylation of the long-chain fatty acids can produce alkanes in the same range as diesel fuels. If the fatty acids are produced via hydrolysis of the original triglycerides in the plant material, then they will exist in an aqueous phase. A simple biofuel process would perform the subsequent decarboxylation in the aqueous phase as well. Thus, we investigated the catalytic decarboxylation of a model fatty acid in high-temperature water. We first tested different catalysts to screen for activity. A heterogeneous catalyst that was 5% palladium on activated carbon (Pd/C) proved to be effective in catalyzing the decarboxylation of palmitic acid in high temperature water. The selectivity was more than 90% toward pentadecane, the decarboxylation product. We used mini-batch reactors to examine the effect of the catalyst loading, reactant loading, and temperature on the decarboxylation rate. The figure below shows representative data. All of the data were used to determine the reaction kinetics and activation energy.