ASSESSMENT OF TEXTURAL CONSEQUENCES ON PRODUCTS OF THERMAL-DECOMPOSITION OF SAMARIUM ACETYLACETONATE

Textural consequences of the thermal decomposition of Sm(C5H7O2)(3) . 2H(2)O in dry nitrogen have been assessed by the analysis of nitrogen sorption isotherms, measured at -196 degrees C, for their decomposition products obtained at different temperatures (300, 450 and 800 degrees C), using a number of widely accepted methods. Subsequently, a correlation was made of the results with physicochemical properties of the decomposition products and with the processes occurring during the course of the decomposition reaction. Thermal processes occurring throughout the decomposition range (100-800 degrees C) were monitored by thermogravimetry, differential thermal analysis and infrared (IR) spectroscopic analysis of the gaseous products. These processes were characterized on the basis of the solid products analyzed using X-ray diffractometry and IR spectrometry. The results showed that Sm(C5H7O2)(3) had completely decomposed to Sm2O3 at 750 degrees C, via the amorphous and unstable intermediates Sm(CH3COO)(C5H7O2)(2) at 150 degrees C, Sm(CH3COO)(2)(C5H7O2) at 235 degrees C, Sm(CH3COO)(3) at 270 degrees C, Sm2O(CH3COO)(3) at 500 degrees C and Sm2O2(CO3) at 650 degrees C. The gases evolved in the gas phase included propyne, acetone, carbon oxides, methane and isobutene. Methane and isobutene resulted from an interfacial reaction involving the initial product (acetone). The final solid product Sm2O3 at 800 degrees C is a crystalline porous material, having a surface area of 47 m(2) g(-1).