Predicting the Behaviour of Near-Critical and Supercritical Alcohols at Microwave Frequencies: Validation of Molecular Dynamic Simulations as a Tool that can Substitute for Measurements under Extreme Experimental Conditions

Robinson, David; Irvine, Derek J.; Robinson, John P.; Lester, Edward H.; Kingman, Samuel W.; Dimitrakis, Georgios

Abstract

Equilibrium and non-equilibrium molecular dynamic simulations, predicting the dielectric properties of near-critical and supercritical methanol and ethanol at microwave frequencies have been carried out. The autocorrelation functions of the dielectric relaxation, show dependency on the slow component at the near-critical region for both alcohols. At the supercritical region, two competing relaxation mechanisms are observed, related to the large breakdown of the hydrogen-bonding network and the degree of clustering between the molecules. This approach closely matches experimental data at microwave frequencies and identical temperature and pressure conditions, validating the predictions of how the molecular structure and dynamics manifest themselves into the complex permittivity and dielectric relaxation behaviour. Thus, introducing a modelling-based solution to deliver accurate dielectric property values for materials at supercritical conditions for “a priori” screening of solvents, whilst removing the need to overcome engineering and safety challenges associated with the development of experimental equipment to practically generate such data.

Citation

Robinson, D., Irvine, D. J., Robinson, J. P., Lester, E. H., Kingman, S. W., & Dimitrakis, G. (2019). Predicting the Behaviour of Near-Critical and Supercritical Alcohols at Microwave Frequencies: Validation of Molecular Dynamic Simulations as a Tool that can Substitute for Measurements under Extreme Experimental Conditions. Journal of Supercritical Fluids, 146, 165-171. https://doi.org/10.1016/j.supflu.2019.01.018

• Journal Article Type: Article
• Acceptance Date: Jan 25, 2019
• Online Publication Date: Jan 30, 2019
• Publication Date: 2019-04
• Deposit Date: Feb 1, 2019
• Publicly Available Date: Jan 31, 2020
• Journal: The Journal of Supercritical Fluids
• Print ISSN: 0896-8446
• Electronic ISSN: 1872-8162
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 146
• Pages: 165-171
• DOI: https://doi.org/10.1016/j.supflu.2019.01.018
• Keywords: Complex permittivity; dielectric relaxation times; molecular dynamics simulations; Drude polarisable force-field
• Public URL: https://nottingham-repository.worktribe.com/output/1513339
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0896844618304662
• Contract Date: Feb 1, 2019