Diffusivities in Binary Mixtures of Ammonia Dissolved in n-Hexane, 1-Hexanol, or Cyclohexane Determined by Dynamic Light Scattering and Molecular Dynamics Simulations

Piszko M, Lenahan F, Steinacker SL, Klein T, Fröba AP (2023)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2023

Journal

Journal of Chemical and Engineering Data American Chemical Society

Book Volume: 68

Pages Range: 2585–2598

Journal Issue: 10

DOI: 10.1021/acs.jced.3c00437

Abstract

Binary mixtures of ammonia (NH3) dissolved in cyclohexane, n-hexane, or 1-hexanol are investigated by dynamic light scattering, polarization-difference Raman spectroscopy (PDRS), and equilibrium molecular dynamics (EMD) simulations. Investigations are performed in macroscopic thermodynamic equilibrium at or close to saturation conditions up to pressures p of 3 MPa and at temperatures T between 303 and 423 K. Besides studying the influence of a polar gas dissolved in a liquid on the Fick or mutual diffusion coefficient D11, the applicability of EMD simulations to systems consisting of polar/polar or nonpolar/polar solvent/solute combinations is also evaluated. At small compositions of NH3, D11 in mixtures with cyclohexane or 1-hexanol shows the expected Arrhenius-like increase with increasing T. For mixtures of n-hexane and NH3, a departure from the expected increase with T is observed at low T, which is related to a strong clustering of the NH3 molecules, leading to a slowing down of D11. This behavior can be related to the weak interactions between polar NH3 and nonpolar n-hexane. In comparison, much stronger interactions are observable between polar NH3 and polar 1-hexanol. The composition-dependent trend of D11 in mixtures of n-hexane or 1-hexanol with NH3 is also investigated. Here, D11 increases with increasing amount of dissolved NH3 in mixtures of 1-hexanol + NH3 for all investigated T. For n-hexane + NH3, at the lowest T, D11 is first constant and increases afterwards with increasing amount of dissolved NH3. At larger T, D11 is first constant and slightly decreases afterwards. Due to a lack of solubility data, the composition of the investigated mixtures could not be determined by PDRS. Yet, the composition-dependent intensity ratios between contributions related to NH3 and the respective solvent obtained from PDRS are reported. This allows the determination of composition, once reliable solubility data are available.

Authors with CRIS profile

Maximilian Piszko Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Frances Lenahan Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Sarah-Lena Steinacker Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Tobias Klein Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Andreas Paul Fröba Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP)

Additional Organisation(s)

Erlangen Graduate School in Advanced Optical Technologies (SAOT)

Related research project(s)

Characterization of molecular diffusion in liquids with dissolved gases July 1, 2019 - June 30, 2023

How to cite

APA:

Piszko, M., Lenahan, F., Steinacker, S.-L., Klein, T., & Fröba, A.P. (2023). Diffusivities in Binary Mixtures of Ammonia Dissolved in n-Hexane, 1-Hexanol, or Cyclohexane Determined by Dynamic Light Scattering and Molecular Dynamics Simulations. Journal of Chemical and Engineering Data, 68(10), 2585–2598. https://doi.org/10.1021/acs.jced.3c00437

MLA:

Piszko, Maximilian, et al. "Diffusivities in Binary Mixtures of Ammonia Dissolved in n-Hexane, 1-Hexanol, or Cyclohexane Determined by Dynamic Light Scattering and Molecular Dynamics Simulations." Journal of Chemical and Engineering Data 68.10 (2023): 2585–2598.

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