Investigation on the <i>pρT</i> Property of a Thymol/Decanoic Acid Eutectic Mixture

Due to the advantages of hydrophobility and low viscosity, type V (deep) eutectic solvents have attracted more and more attention in recent years. However, the p-ρ-T property of the type V solvent is still scarce, which limited its further application. In this work, the high-pressure liquid densities of thymol/decanoic acid eutectic solvents at molar ratios of 2:3, 1:1, and 3:2 were measured using a vibrating-tube densimeter. The studied temperature range was from 293.15 to 363.15 K and the maximum pressure reached was 40 MPa. The combined expanded uncertainty for the present density measurement was estimated to be lower than 0.96 kg·m–3 at a confidence level of 95%. The experimental results were correlated using a Tait-type equation and a multiparametric equation, respectively. The average absolute relative deviation between the experimental data and calculated values is within 0.006% for the Tait equation and 0.007% for the multiparametric equation. In addition, the isothermal compression coefficient, isobaric thermal expansion coefficient, and internal pressure of thymol/decanoic acid solvents were calculated and discussed.