(145g) Prediction of Vapor and Sublimation Pressure for Pure Compounds from the Modified PR+Cosmosac Equation of State

Vapor pressure for pure liquids and solids is an important physical property for many applications in chemical engineering process. Although they can be obtained by experiment whenever possible, there are cases when direct measurement is not allowed, for example, for chemically unstable species in the pure state and for newly synthesized species where often very limited amount of quantity is available. It is therefore desirable to have a predictive tool prior to measurement. In this study, the PR+COSMOSAC EOS is used for such a purpose. In particular, two modifications are introduced to increase the accuracy of the prediction near and below the triple point. The overall average logarithmic deviation for vapor pressure (ALD-P) for 1124 pure liquids from the modified version of PR+COSMOSAC EOS is 0.229 (138%), which is significantly lower than that from the original version (553%). In particular, the ALD-P for the prediction of vapor pressure near triple point reduces from 0.391 (1062%) to 0.321 (233%).  When the melting properties are available, the sublimation pressure can also be estimated. The ALD-P for the sublimation pressure for 1140 substances shows great improvement, from 1.13 (1249%) to 0.71 (413%). These properties predicted from PR+COSMOSAC EOS can further be used for the solubility of drugs in various kinds of solvent. The modified PR+COSMOSAC EOS can provide useful information while the experiment data is not available