Investigation of the thermokinetic properties of magnesium alkoxide-based pioneer organometallic compounds and their use in the synthesis of functional MgO nanoparticles

Single-source organometallic precursors transform the preparation of functional metal oxide nanoparticles with high surface area and periodically layered porous structure into a more controlled systematic method rarely found in the literature. The main goal of the work is to degrade magnesium alkoxides with the structure Me6Mg7(μ3-OR)8 (R= Et, nPr, nBu) under thermogravimetric conditions and convert them into functional MgO. By using different thermokinetic models based on different integral and differential methods, the calculation of quantities such as Ea, ΔH, ΔS for these degradation processes and finally the study of their relationships between the nucleation mechanism and the particle size and morphology were investigated. Thermogravimetric analyzes (TGA) were carried out to study the thermal behavior of the bis-cubic precursors Me6Mg7(μ3-OR)8 (R= Et, nPr, nBu) and reveal their kinetic parameters. TGA experiments were carried out at 2, 5, 7 and 10 °C/min and heating rates at temperatures ranging from 298 K to 873 K under dry air atmosphere. Different techniques have been used to analyze the kinetics of solid state reactions, which can basically be divided into two categories: model development and model-free methods. Although model fitting methods are more commonly used in solid state kinetics and show excellent agreement with experimental data, they can lead to uncertain kinetic parameters, especially in nonisothermal conditions. In this study, various model-free techniques such as KAS, FWO, Starink, Friedman and Vyazovkin isoconversion methods are used to analyze non-isothermal kinetic data and study comparatively the thermal behavior of Me6Mg7(μ3-OR)8 (R= Et, nPr, nBu) molecules.