Synthesis of NiMo catalysts supported on Mn-Al2O3 for obtaining green diesel from waste soybean oil

Abstract

The influence of adding manganese to an Al2O3 support for preparing NiMo catalysts for the hydroconversion of soybean oil was herein evaluated. Two different Mn contents (1 and 5 mol % Mn) were used while Al2O3-Mnx (x = 1 or 5 % mol Mn) were obtained by sol-gel method. The NiMo catalysts were obtained by wetness co-impregnation of nickel and molybdenum precursors onto the as-formed supports considering two different pH of impregnation (5 or 9). Solids were then characterized at the oxide state at different stages of preparation before being sulfided at 400 °C for 4 h with 10 % H2S/H2. Catalysts were then characterized at the sulfide state and evaluated for the hydroconversion of new and waste soybean oil at 380 °C, PH2 = 40 bars. Results show clearly the superiority of NiMo catalysts supported on Al2O3 with 1% mol Mn for the hydroconversion of new and waste soybean oil due to the stabilization of manganese oxide species on the alumina support helping to redisperse the Ni-promoted MoS2 active phase. This study shows that through a precise control of the addition of manganese to Al2O3, it is possible to obtain very highly active NiMo catalysts for the hydroconversion of vegetable oils.