CHARACTERIZATION OF THE DECOMPOSITION PRODUCTS OF ZIRCONIUM ACETYLACETONATE - NITROGEN ADSORPTION AND SPECTROTHERMAL INVESTIGATION

The thermal decomposition reactions of zirconium acetylacetonate in dry nitrogen were thoroughly studied. Thermal processes occurring throughout the decomposition range (100-800 degrees C) were monitored by means of thermogravimetry, differential thermal analysis and IR spectroscopic analysis of the gaseous products. These processes were characterized on the basis of the solid products analyses using X-ray diffractometry and IR spectroscopy. The results showed that the square antiprism Zr(C5H7O2)(4) had completely decomposed to tetragonal ZrO2 at 800 degrees C, through intermediates Zr(CH3COO)(2)(C5H7O2)(2) at 190 degrees C, ZrO(CH3COO)(2) at 340 degrees C and ZrOCO3 at 450 degrees C. The latter decomposed immediately to give ZrO2 at 800 degrees C. Gas-phase products included propyne, acetone, carbon oxides, methane and isobutene. Methane and isobutene resulted from interfacial reaction involving the initial product (acetone). The texture analyses of the thermal decomposition products obtained at different temperatures (300-800 degrees C) were assessed by the analysis of nitrogen isotherms, using a number of widely accepted methods. The results of nitrogen adsorption, scanning electron microscopy and X-ray diffractometry showed that the final product ZrO, developed micro- and mesoporous texture and a growing crystallinity.