The vapor pressures of acetonitrile have been measured over the temperature and pressure range of 278 K and 4.3 kPa to 540 K and 4455 kPa. The upper limit exceeds the temperature at which decomposition of acetonitrile begins (about 536 K) so we were able to assess the effect of pyrolysis on the vapor pressures. Acetonitrile is strongly hygroscopic, and a comparison of results obtained with "wet" and "dry" samples allowed us to investigate in a similar way the effect of water as an impurity. The results have been correlated using generalized Wagner equations, a key feature of which is the use of the reversed reduced temperature = 1 - T/Tc where Tc is the critical temperature. The standard form with terms in , 1.5, 2.5, and 5 produced unacceptable systematic deviations; but the equation ln(p/pc) = (Tc/T)(c1 + c1.51.5 + c22 + c2.52.5 + c5.55.5), where pc is the critical pressure, fits our results from 291 K to 535 K with a standard deviation of 63 ? 10-6 in ln p and significantly extends the range of correlation, toward both the triple and critical points, compared with work already in the literature. By extrapolation to Tc = 545.46 K, we obtain 4835 kPa for the critical pressure pc and 167 Pa for the triple-point pressure at Ts+l+g = 229.35 K. An Antoine equation that describes the results below a pressure of 125 kPa with a standard deviation of 1.5 mK in the condensation temperature has also been obtained.
Compounds
#
Formula
Name
1
C2H3N
acetonitrile
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.