Hydrodeoxygenation Of Oil Over Supported Metal Catalysts

In recent years,the study of biodiesel have been paid more attention due to the energy crisis and the serious environmental pollution.Meanwhile,biodiesel via hydrodeoxygenation from renewable oil is the research hotspot because of their excellent properties.However,the composition of oil is complex,it is difficult to analysize the reaction mechanisms.In view of the above problems,the short chain fatty acids—octanoic acid which was as model compounds of vegetable oil was selected for hydrodeoxygenation to look for the suitable and efficient metal catalysts.A series of monometallic catalysts loaded with Ni were prepared and selected the most suitable support for hydrodeoxygenation.Different metals loading on the most suitable support-CeO₂ were prepared,aiming to select the most suitable catalyst for hydrodeoxygenation of octanoic acid.Compared with other monometallic catalyst,Ni/CeO₂ and Co/CeO₂ showed higher catalytic performance.The selectivity of alkane can reach 64.0%and 74.6%,respectively.Bimetallic catalyst were prepared by doping different metal to Ni or Co based catalysts.The reaction results shows that NiMo/CeO₂ catalyst exhibited the best catalytic effect,compared with other Ni and Co base catalysts.Additionally,The influence of ratio of Ni and Mo also was investagated,1Ni3Mo/CeO₂ showed the highest selectivity of octane up to 73.7%.Results showed that new phases-NiMoO₄,MoO₂ promoting the polarization of C-O keys and the hydrogenation of C=O and C=C keys.On the other hand,the catalyst can reduce the amount of catalyst surface acid and enhance the selectivity of octane with the introduction of Mo.Ni-HPWO₃/CeO₂,Ni-HSiWO₃/CeO₂ and Ni-WO₃/CeO₂ were prepared by the introduction of solid acid into Ni/CeO₂.The experiments results showed that Ni-WO₃/CeO₂ catalyst is more suitable for the hydrodeoxygenation of octanoic acid.In comparison with NiMo/CeO₂,NiMo-WO₃/CeO₂ which has strong L acid showed high selectivity of heptane and octane.With reaction temperature of 280?,the initial pressure of 3 MPa and reaction time of 7 h,the selectivity of heptane and octane for NiMo-WO₃/CeO₂ catalyst were 33.1%and 65.7%,respectively.