Experimental measurement and modeling of the sound speed and refractive index in the ternary system methyl tert-butyl ether + cyclohexane + benzene at 298.15 K under atmospheric pressure

The sound speed and refractive index are fundamental properties of liquid mixtures, providing insights into molecular interactions and structural arrangements. In this study, the sound speed and refractive indices of the ternary system methyl tert-butyl ether (MTBE)+ cyclohexane + benzene and its corresponding binary mixtures MTBE + cyclohexane, MTBE + benzene, and cyclohexane + benzene were experimentally determined over the entire composition range at 298.15 K under atmospheric pressure. The primary goal was to evaluate how well various sound speed models including Nomoto, Van Dael, Junjie, Ernst et al. and Rao along with refractive index mixing rules like Arago-Biot, Lorentz-Lorenz, Newton, Eykman, and Oster, could predict the properties of the mixtures. Experimental results were thoroughly compared with theoretical calculations, and the accuracy of each model was quantified using the mean absolute percentage deviation (MAPD). The results show that some models deliver strong predictive performance, whereas others display considerable discrepancies, highlighting the impact of particular molecular interactions and non-ideal mixing effects. This study offers important understanding regarding the suitability and constraints of acoustic and optical models when applied to complex liquid mixtures.The findings hold practical significance for areas like chemical engineering, the design of optical materials, and the development of pharmaceutical and petrochemical formulations, contributing to enhanced accuracy in modeling the physicochemical properties of multicomponent liquid systems.