Moreover, decarboxylation reaction was carried out for 0.9 g of stearic acid as a model compound to determine an appropriate amount of the catalyst at the conditions of 300 oC/1 MPa (H2) for 120 min. When the two different amounts of Pd/C were studied to be 0.05 and 0.25 g, incomplete conversions were found respectively to be 16.3 and 26.1 mol% from stearic acid into n-heptadecane. On the other hand, 90.3 mol% of n-heptadecane was achieved with 0.45 g of Pd/C. Therefore, it was concluded that 0.45 g of Pd/C is required for the efficient decarboxylation of 0.9 g of fatty acid at the given conditions. In general, decarboxylation of fatty acids proceeds in three phases, gaseous H2, liquid fatty acids and a solid catalyst, in which the mutual accessibility is an impor- tant factor. Although an organic solvent is usually added to improve its accessibility in the literature 121 l, decarboxylation was conducted without any organic solvent in this study to sim plify the reaction process. That might be the reason why such a large amount of PdlC catalyst was needed. Therefore, an effective agitation would be required to reduce the amount of the catalyst.