Thermodynamic modelling of the nature of speciation and phase behaviour of binary and ternary mixtures of formaldehyde, water and methanol
Author(s)
Wehbe, Malak
Haslam, Andrew J
Garcia-Munoz, Salvador
Jackson, George
Galindo, Amparo
Type
Journal Article
Abstract
Formaldehyde is a highly reactive chemical that is usually sold and processed in the form of aque-ous solutions, with methanol added for stability. In these solutions, formaldehyde reacts with thesolvents to form a variety of reaction products, including oligomers. These chemical reactionscan occur in the liquid and vapour phases and have a significant influence on the properties offormaldehyde-containing solutions. Of particular interest to industrial applications is the predictionof the vapour–liquid equilibria (VLE) in formaldehyde solutions, considering the chemical reac-tions. We use the SAFT-γ Mie group-contribution (GC) equation of state to obtain the fluid-phasebehaviour of binary and ternary mixtures of formaldehyde with water and methanol. The oligomeri-sation reactions taking place in aqueous and methanolic solutions of formaldehyde are modelledimplicitly using a physical approach, which is possible within the SAFT-γ Mie framework by addingassociation (reactive) sites that mediate the formation of the reaction products. Using this approach,the nature of the chemical speciation in formaldehyde + water, formaldehyde + methanol andformaldehyde + water + methanol mixtures is studied. A new group, CH2 O, characterising formalde-hyde within the SAFT-γ Mie GC approach, is developed. Experimental data for the VLE in binarymixtures of formaldehyde + water and formaldehyde + methanol are used to obtain the optimalunlike interaction parameters between the corresponding SAFT-γ Mie groups. The newly developedparameters are used to predict the VLE of ternary formaldehyde + water + methanol mixtures for awide range of temperatures and pressures, with excellent agreement to experimental data. Addi-tionally, the SAFT-γ Mie approach is shown to provide accurate predictions of the distribution ofreaction species (oligomers) in binary and ternary mixtures containing formaldehyde.
Date Issued
2023-10-01
Date Acceptance
2023-01-11
Citation
Molecular Physics, 2023, 121 (19-20)
ISSN
0026-8976
Publisher
Taylor and Francis Group
Journal / Book Title
Molecular Physics
Volume
121
Issue
19-20
Copyright Statement
© 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis GroupThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been published allow the posting of the AcceptedManuscript in a repository by the author(s) or with their consent.
License URL
Subjects
AQUEOUS-SOLUTIONS
ASSOCIATING FLUIDS
CARBON-DIOXIDE
CHEMICAL-EQUILIBRIA
Chemistry
Chemistry, Physical
DIRECTIONAL ATTRACTIVE FORCES
EQUATION-OF-STATE
formaldehyde
FREE-ENERGY
group contribution
phase behaviour
Physical Sciences
Physics
Physics, Atomic, Molecular & Chemical
SAFT
SAFT-gamma Mie
Science & Technology
SYSTEM
VAPOR-LIQUID-EQUILIBRIUM
Publication Status
Published
Article Number
e2197712
Date Publish Online
2023-05-22