An atomistic explanation of the ethanol-water azeotrope
Carravetta, Vincenzo ; Gomes, Anderson Herbert de Abreu ; Marinho, Ricardo dos Reis Teixeira ; Öhrwall, Gunnar LU
; Ågren, Hans
; Björneholm, Olle
LU
and de Brito, Arnaldo Naves
(2022)
In Physical Chemistry Chemical Physics
24(42).
p.26037-26045
- Abstract
Ethanol and water form an azeotropic mixture at an ethanol molecular percentage of ∼91% (∼96% by volume), which prohibits ethanol from being further purified via distillation. Aqueous solutions at different concentrations in ethanol have been studied both experimentally and theoretically. We performed cylindrical micro-jet photoelectron spectroscopy, excited by synchrotron radiation, 70 eV above C1s ionization threshold, providing optimal atomic-scale surface-probing. Large model systems have been employed to simulate, by molecular dynamics, slabs of the aqueous solutions and obtain an atomistic description of both bulk and surface regions. We show how the azeotropic behaviour results from an unexpected concentration-dependence of the... (More)
Ethanol and water form an azeotropic mixture at an ethanol molecular percentage of ∼91% (∼96% by volume), which prohibits ethanol from being further purified via distillation. Aqueous solutions at different concentrations in ethanol have been studied both experimentally and theoretically. We performed cylindrical micro-jet photoelectron spectroscopy, excited by synchrotron radiation, 70 eV above C1s ionization threshold, providing optimal atomic-scale surface-probing. Large model systems have been employed to simulate, by molecular dynamics, slabs of the aqueous solutions and obtain an atomistic description of both bulk and surface regions. We show how the azeotropic behaviour results from an unexpected concentration-dependence of the surface composition. While ethanol strongly dominates the surface and water is almost completely depleted from the surface for most mixing ratios, the different intermolecular bonding patterns of the two components cause water to penetrate to the surface region at high ethanol concentrations. The addition of surface water increases its relative vapour pressure, giving rise to the azeotropic behaviour.
(Less)
- author
- Carravetta, Vincenzo
; Gomes, Anderson Herbert de Abreu
; Marinho, Ricardo dos Reis Teixeira
; Öhrwall, Gunnar
LU
; Ågren, Hans
; Björneholm, Olle
LU
and de Brito, Arnaldo Naves
- organization
- publishing date
- 2022-10-14
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Chemistry Chemical Physics
- volume
- 24
- issue
- 42
- pages
- 26037 - 26045
- publisher
- Royal Society of Chemistry
- external identifiers
-
- scopus:85140467634
- pmid:36268753
- ISSN
- 1463-9076
- DOI
- 10.1039/d2cp03145k
- language
- English
- LU publication?
- yes
- id
- c5f2dbb6-3331-4564-a27f-69eb896ef7df
- date added to LUP
- 2023-01-13 14:14:39
- date last changed
- 2024-06-28 00:37:02
@article{c5f2dbb6-3331-4564-a27f-69eb896ef7df,
abstract = {{<p>Ethanol and water form an azeotropic mixture at an ethanol molecular percentage of ∼91% (∼96% by volume), which prohibits ethanol from being further purified via distillation. Aqueous solutions at different concentrations in ethanol have been studied both experimentally and theoretically. We performed cylindrical micro-jet photoelectron spectroscopy, excited by synchrotron radiation, 70 eV above C1s ionization threshold, providing optimal atomic-scale surface-probing. Large model systems have been employed to simulate, by molecular dynamics, slabs of the aqueous solutions and obtain an atomistic description of both bulk and surface regions. We show how the azeotropic behaviour results from an unexpected concentration-dependence of the surface composition. While ethanol strongly dominates the surface and water is almost completely depleted from the surface for most mixing ratios, the different intermolecular bonding patterns of the two components cause water to penetrate to the surface region at high ethanol concentrations. The addition of surface water increases its relative vapour pressure, giving rise to the azeotropic behaviour.</p>}},
author = {{Carravetta, Vincenzo and Gomes, Anderson Herbert de Abreu and Marinho, Ricardo dos Reis Teixeira and Öhrwall, Gunnar and Ågren, Hans and Björneholm, Olle and de Brito, Arnaldo Naves}},
issn = {{1463-9076}},
language = {{eng}},
month = {{10}},
number = {{42}},
pages = {{26037--26045}},
publisher = {{Royal Society of Chemistry}},
series = {{Physical Chemistry Chemical Physics}},
title = {{An atomistic explanation of the ethanol-water azeotrope}},
url = {{http://dx.doi.org/10.1039/d2cp03145k}},
doi = {{10.1039/d2cp03145k}},
volume = {{24}},
year = {{2022}},
}