Metrics for estimating vapour pressure deviation from ideality in binary mixtures

ABSTRACT

A novel method is introduced for estimating the degree of interactions occurring between two different compounds in a binary mixture resulting in deviations from ideality as predicted by Raoult’s law. Metrics of chemical similarity between binary mixture components were used as descriptors and correlated with the Root-Mean Square Error (RMSE) associated with Raoult’s law calculations of total vapour pressure prediction, including Abraham descriptors, sigma moments, and several chemical properties. The best correlation was for a quantitative structure-activity relationship (QSAR) equation using differences in Abraham parameters as descriptors (r² = 0.7585), followed by a QSAR using differences in COSMO-RS sigma moment descriptors (r² = 0.7461), and third by a QSAR using differences in the chemical properties of log K_AW, melting point, and molecular weight as descriptors (r² = 0.6878). Of these chemical properties, Δlog K_AW had the strongest correlation with deviation from Raoult’s law (RMSE) and this property alone resulted in an r² of 0.6630. These correlations are useful for assessing the expected deviation in Raoult’s law estimations of vapour pressures, a key property for estimating inhalation exposure.

KEYWORDS:

• Chemical mixtures
• QSAR
• Raoult’s law
• Abraham descriptors
• chemical similarity
• vapour pressure estimation

Acknowledgments

The authors would like to acknowledge CEFIC for funding this work under the LRI-B22 project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data can be made available by contacting the corresponding author at [email protected].

Supplementary data

Supplemental data for this article can be accessed at: https://doi.org/10.1080/1062936X.2023.2280634.

Additional information

Funding

The work was supported by European Chemical Industry Council [LRI-B22].