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 decompositio n products obtained at different temperatures (300, 450 and 800 degree s C), using a number of widely accepted methods. Subsequently, a corre lation was made of the results with physicochemical properties of the decomposition products and with the processes occurring during the cou rse of the decomposition reaction. Thermal processes occurring through out the decomposition range (100-800 degrees C) were monitored by ther mogravimetry, differential thermal analysis and infrared (IR) spectros copic analysis of the gaseous products. These processes were character ized on the basis of the solid products analyzed using X-ray diffracto metry and IR spectrometry. The results showed that Sm(C5H7O2)(3) had c ompletely decomposed to Sm2O3 at 750 degrees C, via the amorphous and unstable intermediates Sm(CH3COO)(C5H7O2)(2) at 150 degrees C, Sm(CH3C OO)(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, me thane and isobutene. Methane and isobutene resulted from an interfacia l reaction involving the initial product (acetone). The final solid pr oduct Sm2O3 at 800 degrees C is a crystalline porous material, having a surface area of 47 m(2) g(-1).