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 produc tion of polyacetal plastics. In such processes aqueous solutions of methyla l and methanol have to be treated by distillation. This contribution report s experimental results for the phase equilibrium in such mixtures: vapor-li quid 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 sys tem (water + methanol + methylal) at 303 less than or equal to T/K less tha n 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 t han 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.