Thermodynamics of chromium acetylacetonate sublimation

The equilibrium sublimation pressure Cr(acac)3(s) = Cr(acac)3(g) was measured in the range 320 ≤ T (K) ≤ 476 by two procedures. One of them is Knudsenʹs effusion procedure with mass spectrometric analysis of the composition of the gas phase, which proved to be good in measuring low pressure. The second is mass spectrometric procedure “calibrated volume method” (CVM), which helped us to expand the possibilities of the effusion method toward high pressure range. Experimental data are in good agreement with each other. For this process were obtained ln(P (Pa)) = 39.197 − 15 308.5/T, enthalpy ΔsubH° (T) = 127.28 ± 0.22 kJ mol−1 and entropy ΔsubS° (T) = 230.1 ± 0.5 J mol−1 K−1.