Vapor-liquid and liquid-liquid equilibria in binary and ternary mixtures of water, methanol, and methylal

Methylal is a byproduct in industrial processes, for example, in the production of polyacetal plastics. In such processes aqueous solutions of methylal and methanol have to be treated by distillation. This contribution reports experimental results for the phase equilibrium in such mixtures: vapor-liquid equilibrium of the binary systems (water + methylal) at 284 less than or equal to T/K less than or equal to 388 and (methanol + methylal) at 303 less than or equal to T/K less than or equal to 348, and of the ternary system (water + methanol + methylal) at 303 less than or equal to T/K less than or equal to 363, as well as liquid-liquid equilibrium of(water + methylal) and (water + methanol + methylal) at 273 less than or equal to T/K less than or equal to 313. Furthermore, new experimental results are reported for the vapor pressure of methylal at 318 less than or equal to T/K less than or equal to 357. The new experimental phase equilibrium data are correlated using the UNIQUAC model to describe the Gibbs excess energy of the liquid mixtures.