Biokerosene and green diesel from macauba oils via catalytic deoxygenation over Pd/C

• Macauba Pulp and kernel oils were deoxygenated to produce drop in biofuels on Pd/C.
• FTIR was used as an efficient assay to quantify the synthesized biohydrocarbons.
• Higher hydrocarbon percentages were obtained with the previously hydrolysed oils.
• Higher H2 pressure favored deoxygenation of pulp oil but not kernel derivatives.
• The produced hydrocarbons can be used for green diesel or biojet fuel formulation.

Macauba is a palm tree with good oil productivity (6.2 ton/ha), is native to Central and South America and is not exploited for food purposes. Its oils have been noted as an important alternative for the production of biofuels, especially for aviation. This study investigated deoxygenation catalysed by 5% w/w of palladium on charcoal (Pd/C) reduced in situ using crude and previously hydrolysed macauba pulp and almond oils with different compositions and acidity values. The effect of the fatty composition and nature of the feedstock, reaction pressure, atmosphere, presence of stirring and use of the Pd/C catalyst were studied. The results indicated high selectivity, with a predominance of saturated linear hydrocarbons that correspond to green diesel, followed by biojet fuel hydrocarbons. Oxygen removal was favoured for free fatty acids with long carbon chains, for which decarbonylation and/or decarboxylation predominates. The highest content of hydrocarbons (85% w/w) was obtained in the reaction of hydrolysed macauba almond oil at 10 bar of H2, 300 °C, 5 h of reaction and stirring at 700 rpm. This green product has potential applications as a drop-in substitute for fossil fuels.

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