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

Abstract

Abstract-In this study, a thermodynamic model was combined with the conductor-like screening model for real solvents (COSMO-RS), coupled with chemical reaction equilibrium and mass balance, for describing the phase behavior and complex chemical equilibrium in the ternary system of formaldehyde-water-trioxane at temperatures between 413 K. New approach for the prediction of vapor-liquid equilibrium of the binary system (TOX + W) and the ternary system (FA+W+TOX) is compared with experimental data and UNIFAC method. The calculated vapor-liquid equilibrium (VLE) result shows good agreement with the experimental data. The COSMO-RS model has proven to be an accurate and effective method for predicting the activity coefficient, and also more reasonable for predicting the thermodynamic properties of formaldehyde-watermethanol reactive fluids.Index Terms-COSMO-RS, modeling, phase equilibrium, formaldehyde aqueous solution, trioxane.