CHARACTERIZATION OF LANTHANUM OXIDE FORMED AS A FINAL DECOMPOSITION PRODUCT OF LANTHANUM ACETYLACETONATE - THERMOANALYTICAL, SPECTROSCOPIC AND MICROSCOPIC STUDIES

The porous and high surface area of lanthanum oxide was obtained as a final decomposition product of lanthanum acetylacetonate tetrahydrate. The decomposition course in dry nitrogen was thoroughly studied. Ther mal processes occurring throughout the decomposition range (100-800 de grees C) were monitored by thermogravity; differential thermal analysi s and infrared spectroscopy gaseous products. These processes were cha racterized on the basis of the solid products analyses, using X-ray di ffractometry and IR-spectrometry. The results showed La(C5H7O2)(3) com pletely decomposed to La2O3 at 730 degrees C, through amorphous and un stable intermediates La(CH3COO)(C5H7O2)(2) at 190 degrees C, La(CH3COO )(2)(C5H7O2) at 225 degrees C, La(CH3COO)(3) at 285 degrees C, La-2(CO 3)(3) at 390 degrees C and crystalline and stable La2O2(CO3) at 430 de grees C. Gas phase decomposition products included propyne, acetone, c arbon oxides, methane and isobutene. Methane and isobutene resulted fr om interfacial reactions involving the initial product (acetone). The ultimate products, La2O3 at 700 degrees C and 800 degrees C, are cryst alline porous solids and having a surface area of 21 and 45 m(2)/g res pectively.