Vapor‐liquid and chemical equilibria of formaldehyde‐water mixtures

Abstract

Abstract A physicochemical model of the thermodynamic properties of formaldehyde‐containing mixtures was revised and extended using new experimental data for vapor–liquid and chemical equilibria. The new vapor–liquid equilibrium data of the formaldehyde–water system were taken for very diluted (formaldehyde concentrations as low as 0.07 mass %) and very concentrated (up to 71 mass %) formaldehyde solutions at temperatures between 363 and 423 K and pressures up to about 650 kPa. The new chemical equilibrium data were obtained applying 13 C‐NMR spectroscopy to the same system at temperatures between 338 and 383 K at formaldehyde concentrations of up to about 62 mass %. Results from both investigations were used simultaneously—together with data from the literature—to improve a physicochemical model of the thermodynamic properties of aqueous solutions of formaldehyde.