Second generation biodiesel, so-called bio-hydrogenated diesel (BHD), can be produced from hydro treatment of vegetable oils. The hydrogenation (HDO) of oleic acid and palmitic acid as model compounds of palm oil over unsupported Ni-Mo and Co-Mo sulfide catalysts was performed in a Parr reactor to produce BHD. The effects of reaction parameters: temperature, hydrogen pressure and the atomic ratio of catalysts (Ni/(Ni + Mo) or Co/(Co + Mo)) on the conversion and product yields (mainly n-C-15, n-C-16, n-C-17 and n-C-18 hydrocarbons) were evaluated. The results show that the high pressure favored HDO pathway, while high temperature strongly affected the decarboxylation and decarbonylation pathways. At optimal conditions for oleic acid HDO, the efficient catalyst was NiMoS2 catalyst (Ni/(Ni + Mo) = 0.2) which gave high oleic acid conversion (100%), n-C-18 selectivity (78.8%) and n-C-18 yield (70.3%) whereas, for palmitic acid HDO, NiMoS2 catalyst (Ni/(Ni + Mo) = 0.2) also gave high palmitic acid conversion (95.2%), n-C-16 selectivity (78.5%) and n-C-16 yield (65.6%). (C) 2019 Elsevier Ltd. All rights reserved.