2022 Annual Meeting
(444d) Thermodynamic Modeling of the Nature of Speciation and Phase Behavior of Binary and Ternary Mixtures of Formaldehyde, Water and Methanol
Authors
In the SAFT-g Mie framework, molecules are modelled as heteronuclear chains formed from fused spherical segments, which represent the distinct functional groups comprising the molecule. In this framework, it is assumed that the properties of a molecule or a mixture can be determined from the weighted contributions of the functional groups present in the system of interest, with the assumption that the parameters characterizing the functional groups are fully transferable across molecules.
In this work, the oligomerization reactions taking place in formaldehyde-containing aqueous and methanolic solutions are modeled implicitly using a physical approach which is possible within the SAFT-g Mie framework by adding association (reactive) sites to mediate the formation of the reaction products. Here, the reaction products are considered to be aggregates of the reactants. First, we use experimental data for the VLE in binary mixtures of formaldehyde-water and formaldehyde-methanol to obtain the optimal unlike interaction parameters between the corresponding SAFT-g Mie groups. Then, the newly developed parameters are used to predict the VLE of ternary formaldehyde-water-methanol mixtures, for a wide range of temperatures and pressures, with excellent agreement to experimental data. Finally, the distribution of reaction species (oligomers) in binary and ternary mixtures is predicted using the SAFT-g Mie EoS with remarkable agreement to experimental data.
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