Deviations from Ideality: Quantum Cluster Equilibrium Theory and the Methanol-Benzene Binary Mixture
Location
King Building 237
Document Type
Presentation
Start Date
4-27-2018 5:30 PM
End Date
4-27-2018 6:50 PM
Abstract
The methanol-benzene binary mixture, which has an azeotrope with a 3:2 methanol:benzene molar ratio at 329 K, provides a useful system through which to study the computation of thermodynamic properties of non-ideal mixtures. Methanol-benzene clusters of various molar ratios up to mixed pentamers are described with Density Functional Theory (DFT) to model possible interactions in the binary liquid. Thermodynamic data, cluster populations, and phase transitions are then calculated using Quantum Cluster Equilibrium (QCE) theory in order to evaluate the efficacy of current computational methods in describing deviations from ideality. Vibrational entropy, enthalpy of mixing, Gibbs free energy of mixing, and boiling points are shown to be highly dependent upon the types of normal mode deflections calculated for individual clusters, indicating that vibrational anharmonicity plays an important role in describing thermodynamic behavior. By accounting for the anharmonic characteristics of this non-ideal mixture, azeotropic behavior can be accurately and robustly modeled.
Keywords:
chemistry, computational chemistry, theoretical chemistry, statistical thermodynamics, applied mathematics, quantum mechanics
Recommended Citation
Vigilante, Nic, "Deviations from Ideality: Quantum Cluster Equilibrium Theory and the Methanol-Benzene Binary Mixture" (04/27/18). Senior Symposium. 78.
https://digitalcommons.oberlin.edu/seniorsymp/2018/presentations/78
Major
Chemistry; Viola Performance
Advisor(s)
Manish Mehta, Chemistry and Biochemistry
Kristen Docter, Viola Performance
Project Mentor(s)
Anne-Marie Kelterer, Institut für Physikalische und Theoretische Chemie, Technische Universität Graz
April 2018
Deviations from Ideality: Quantum Cluster Equilibrium Theory and the Methanol-Benzene Binary Mixture
King Building 237
The methanol-benzene binary mixture, which has an azeotrope with a 3:2 methanol:benzene molar ratio at 329 K, provides a useful system through which to study the computation of thermodynamic properties of non-ideal mixtures. Methanol-benzene clusters of various molar ratios up to mixed pentamers are described with Density Functional Theory (DFT) to model possible interactions in the binary liquid. Thermodynamic data, cluster populations, and phase transitions are then calculated using Quantum Cluster Equilibrium (QCE) theory in order to evaluate the efficacy of current computational methods in describing deviations from ideality. Vibrational entropy, enthalpy of mixing, Gibbs free energy of mixing, and boiling points are shown to be highly dependent upon the types of normal mode deflections calculated for individual clusters, indicating that vibrational anharmonicity plays an important role in describing thermodynamic behavior. By accounting for the anharmonic characteristics of this non-ideal mixture, azeotropic behavior can be accurately and robustly modeled.
Notes
Session VII, Panel 19 - Physical | Science
Moderator: Dan Stinebring, Francis D. Federighi Professor of Physics