Revised vapor‐liquid equilibrium model for multicomponent formaldehyde mixtures

Abstract

Formaldehyde is one of the most important intermediate products of the chemical industry. Due to its high reactivity, it is commonly handled in aqueous or methanolic solutions. In these solutions, formaldehyde is dissolved chemically. Therefore, modeling thermodynamic properties of aqueous and methanolic formaldehyde-containing mixtures require the consideration of chemical reactions and physical effects. A recently published physico-chemical model (Maurer, 1986) for the description of vapor-liquid equilibria of these systems is tested and improved on the basis of about 140 new experimental data points for mixtures containing formaldehyde, water, methanol, and trioxane at temperatures between 320 and 380 K and pressures below 100 kPa. Improvements are achieved by fitting some of those binary interaction parameters, which formerly had to be estimated due to the lack of experimental data. The revised model is able to reliably predict vapor-liquid equilibria in multicomponent formaldehyde-containing mixtures.

Necessary and sufficient conditions for reactive azeotropes in multireaction mixtures

“…Little has been published on the experimental characterization of reactive azeotropes, and in the case of multiple chemical reactions it is difficult to analyze and understand experimental results without a theoretical thermodynamic framework. Experimental vapor-liquid equilibrium (VLE) measurements are available for the reacting systems water-formaldehyde, and water-formaldehyde--methanol, and these data have been studied carefully in the context of reactive azeotropy by Green and Vener (19551, Brandani et al (1980), Brandani and Di Giacomo (1984), Maurer (1986), and Hasse et al (1990). In this article we derive general results regarding reactive azeotropy in a multicomponent system undergoing multiple equilibrium reactions.…”

Enthalpy change on vaporization of aqueous and methanolic formaldehyde solutions

“…Figure 1) especially designed for the measurement of enthalpy changes of chemical reactive mixtures upon vaporization. A similar though noncalorimetric technique has been successfully applied to the measurement of vapor-liquid equilibria in formaldehyde-containing mixtures (Maurer, 1986;Hasse et al, 1990). The calorimeter as well as results of test runs on pure water have been described elsewhere (Liu, 1991;Liu and Maurer, 1992).…”

“…For formaldehyde-containing mixtures such a model is available for the vapor-liquid equilibrium (Maurer, 1986;Hasse et al, 1990;Hasse and Maurer, 1991a). That physicochemical model can be extended in a straightforward manner to describe enthalpy differences.…”

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A physicochemical model f o r vapor-liquid equilibrium in niulticomponent formaldehyde-containing mixtures (Maurer, 1986;Hasse et al, 1990;Hasse and Maurer, 1991a)

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Prediction of the Vapor–Liquid Equilibrium of Formaldehyde–Water–Trioxane Ternary System by the Conductor-Like Screening Model for Real Solvents

“…The basic design of such processes requires, for example, a model for the vapor-liquid equilibrium of the chemical reactive system formaldehyde + water + trioxane [1]. A physicochemical model used in the description of vapor-liquid equilibrium in formaldehyde-containing mixtures was originally developed by Maurer [2], and has been continuously updated [1], [3]- [7].…”