Vapor–liquid and liquid–liquid equilibrium in mixtures of water + isobutanol/n-butanol + isobutylal/n-butylal

Producing the oxygenate butylal from formaldehyde and butanol presents the challenge of purifying butylal from mixtures also containing water and butanol, which exhibit both binary and ternary miscibility gaps. We present measurement data on the liquid–liquid equilibrium in the binary systems (water + isobutylal) and (water + n-butylal) as well as in the ternary system (water + n-butanol + n-butylal) between 273 K and 353 K. Additionally, measurement data on the isobaric binary vapor–liquid equilibrium in the systems (isobutanol + isobutylal) and (n-butanol + n-butylal) is reported between 35 kPa and 95 kPa. The pure component vapor pressures of isobutylal and n-butylal are measured between 383 K and 450 K. A UNIQUAC model is developed to predict the vapor–liquid topology of the ternary system (water + butanol + butylal). This allows for identifying butylal as an obtainable distillation product for the most technically relevant feeds. • Research on the VLLE of mixtures of water, butanol, and butylal. • Liquid–liquid measurements between 278 K and 353 K. • Isobaric vapor–liquid measurements between 35 kPa and 95 kPa. • Utilization of a UNIQUAC model for identifying obtainable distillation products.