Thermodynamic and molecular simulation analysis of molecular interactions between methyl 2–hydroxyisobutyrate + water or n–alkanol (C1–C2) mixtures

Abstract

Methyl 2–hydroxyisobutyrate (HBM) is essential as a photoresist thinner in semiconductor fabrication. In this study, we examined the density and viscosity of HBM combined with water or alkanol (C1–C2) at a pressure of 0.1 MPa and temperatures ranging from 288.15 K to 323.15 K. Based on experimental data, we calculated the excess molar volume, as well as apparent, partial, and excess partial molar volumes, and deviations in viscosity. These derived thermodynamic properties were then modeled using the Redlich-Kister (RK) polynomial equation. The VmE values of HBM + water mixtures are more negative compared to HBM + alkanol mixtures because of the stronger H–bonding interactions in HBM–water than in HBM–alkanol. With increasing temperature, the VmEbecome more negative, whereas the Δη values lower with a temperature rise. The values for excess molar volume and deviation in viscosity were analyzed through a graph theoretical method. Additionally, the excess free energy of activation was determined from the viscosity data. FTIR spectral analysis validated the findings related to intermolecular interactions and the graph theoretical method. Lastly, molecular dynamics simulations shed light on the intermolecular interaction energies and their differences in the studied binary systems.