Preparation and Thermal Properties of Nano-Lanthanum Complexes with Alendronic Acid

摘要

Alendronic acid was synthesized through phosphorylation and hydrolysis in a non-protonic environment using 4-aminobutanoic acid, phosphorous acid, and phosphorus trichloride as the starting materials. Subsequently, lanthanum complexes with alendronic acid (La-Aa) were prepared under hydrothermal conditions. The structure and morphology of the La-Aa complexes were characterized with Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy, as well as scanning electron microscopy. Additionally, the thermal properties of the complexes were investigated by thermogravimetric and differential thermogravimetric analyses. The resultant thermogravimetric analysis curves indicate that the thermal weight loss process of the La-Aa complexes involves two stages, namely, C-C and C-P bond cleavage. The average apparent activation energies (E-a) of thermal decomposition of the C-C and C-P bonds are 260.94 kJ/mol and 177.29 kJ/mol, respectively, as determined by the Kissinger method. Furthermore, according to the Phadnis-Deshpande model, the first and second decomposition kinetic models of the La-Aa complexes follow a power law and nuclei growth mechanism, respectively.