New Correlation for Second Virial Coefficients by Using Refractive Index

The development of a virial equation of state requires understanding numerous interaction virial coefficients. Given the relationship between these coefficients and the intermolecular potential, the corresponding states principle (CSP) can also be applied to extend its use to virial coefficients. In this study, the second virial coefficient has been developed using molar refraction. Molar refraction (R) is directly related to a substance's polarizability, which influences how molecules interact with each other. The more polarizable a molecule is, the stronger the attractive forces between them, which affects the second virial coefficient. This correlation has been theoretically sound since it is based on the molar refraction of compounds instead of depending on anacentric factor. Furthermore, this new correlation is characterized by minimum data requirement for calculation; only temperature. This correlation is agreed upon in the literature for several non-polar compounds.The new correlation provided satisfactory results for light non-polar compounds at low temperatures across all comparisons. For heavy non-polar compounds, its performance surpassed that of previous correlations based on the acentric factor. Additionally, both the new and previous correlations produced good results at high temperatures. Keywords: Second virial coefficients; Thermodynamic; Refractive index; Non-polar