Catalytic deoxygenation of triglycerides and fatty acids to hydrocarbons over carbon-supported nickel

The catalytic deoxygenation of triglycerides and fatty acids to hydrocarbons through decarboxylation/decarbonylation (deCO_x) has been investigated in a semi-batch autoclave over 20 wt.% Ni/C and 5 wt.% Pd/C catalysts. The boiling point distribution plots of the reaction products show that 20 wt.% Ni/C tends to yield lighter products in the C10-C17 range than 5 wt.% Pd/C, a fact which may be exploited for fuel blending purposes. Differences in the performance of these two catalysts may be attributed to the higher acidity of the Ni-based formulation, which favors the adsorption of carbonaceous species and the occurrence of cracking reactions. The effect of the gas employed (N₂, 10% H₂/N₂ or H₂) was also examined and while the presence of hydrogen resulted in improved catalytic performance, the optimum hydrogen partial pressure was found to depend on the catalyst used. For triglyceride deoxygenation, analysis of the reaction mixture at different reaction times indicates that the reaction proceeds through the deCO_x of fatty acid intermediates.