LAUSR

A novel method to evaluate volumetric properties, namely the thermal expansivity (αP) and the isothermal compressibility (κT) for nonpolar hydrocarbon systems using refractive index measurements, is presented in this work. New expressions for αP and κT are derived from the Lorentz–Lorenz equation and the One-Third rule, respectively. A further simplified expression for αP is proposed requiring only refractive index data and molecular weight for calculation. Densities and refractive indices of 12 pure nonpolar hydrocarbons, 6 hydrocarbon mixtures, and 3 crude oils are measured at temperatures from 283.15 K up to 343.15 K and at 0.1 MPa. The measured refractive indices are used to calculate αP for a wide range of temperatures using the proposed method, and the measured densities are used to calculate αP for comparison. Reported densities and refractive indices of benzene at 298.15 K and at pressures up to 90 MPa are used for κT evaluations with the proposed method. Values of αP and κT calculated from refrac...