The thermal decomposition reactions of vanadyl and vanadium acetoaceto
nates in dry nitrogen have been thoroughly studied. Thermal processes
occurring throughout the decomposition range (100-500 degrees C) were
monitored by means of TG, DTA and IR spectroscopic analysis of the gas
eous products. These processes were characterized on the basis of the
solid product analyses using X-ray diffractometry and IR spectroscopy.
The results showed that VO(C5H7O2)(2) had completely decomposed to V2
O3 at 325 degrees C through the intermediates VO(CH3COO)(C5H7O2) at 29
0 degrees C, VO(CH3COO)(2) at 300 degrees C and V2O(CO3)(2) at 305 deg
rees C. In contrast, V(C5H7O2)(3) decomposed via the acetate at 280 de
grees C and the carbonate at 299 degrees C as intermediates. The carbo
nate decomposed immediately to give V2O5 at 305 degrees C. Part of the
V2O5 underwent a reduction process through an endothermic effect at 3
25 degrees C. The ultimate solid products at 400 degrees C were V2O3 a
nd V2O5. Gas phase products included propyne, acetone, carbon oxides,
methane and isobutene. Methane and isobutene resulted from interfacial
reaction involving the initial product (acetone).