VAPOR-LIQUID-EQUILIBRIUM OF FORMALDEHYDE MIXTURES CONTAINING METHANOL

A new description of the vapor phase of formaldehyde solutions contain ing methanol is presented. In contrast with all previous models for th ese mixtures, it is recognized that the dimer resulting from the forma ldehyde-methanol reaction has a relatively high volatility and should be considered present in the vapor phase. The new model is matched to the experimental vapor-liquid equilibrium data for binary and ternary mixtures containing formaldehyde, methanol, and water. The proposed mo del represents well vapor-liquid equilibrium of these reacting mixture s and does not reveal systematic deviations for the ternary system as observed with previous models.