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.

Keywords:
Ethyl transesterification; temperature; reaction time; catalyst mass; acidity index