Synthesis of NiMoO4 by the Complexation Method Combining EDTA-Citrate and its Behavior Against Biodiesel Acidity

In this paper, NiMoO4 powder was synthesized by the complexation method combining EDTA-Citrate. The behavior of the NiMoO4 material in the ethyl transesterification reaction was evaluated by analyzing the acidity index under specified reaction conditions. The results showed that NiMoO4 crystallized at 800 °C with a total mass loss of 85%, presenting a monoclinic structure, free of secondary phases, high degree of crystallinity and average crystallite size of 140 nm. The particles had heterogeneous sizes and shapes, but with well-defined contours. The increase in the mass of NiMoO4 in the reaction medium reduced the acidity index (0.8 mgKOH.g-1 with 15 wt.%). Despite the use of the minimum molar ratio (1:3), the ethyl route being less reactive and the use of the operating temperature close to the alcohol evaporation temperature, NiMoO4 showed promising catalytic potential in the transesterification process.