Interfacial Mass Transport in the Ionic Liquid/1-Octene System

Biphasic systems with ionic liquids and various solvents including supercritical and compressed gases are used as an efficient platform for reactions and extractions. However, little mass transfer data exists in the literature for any system involving ionic liquids, which impedes development and scale-up. This presentation will illustrate interfacial mass transport in a model biphasic system with 1-hexyl-3-methyl-imidazolium bis[trifluoromethylsulfonyl)amide ([HMIm][Tf₂N]) and 1-octene. The physical, thermodynamic, and mass transport properties are highly concentration dependent and have been measured. From phase equilibrium studies, the IL has very little solubility in the 1-octene phase, but 1-octene has moderate solubility in the IL phase. This simplifies the analysis as mass transfer occurs in only 1 direction. Interfacial mass transfer studies have been conducted for falling droplets of ionic liquid in a continuum of 1-octene in 1 and 2 meter columns. In addition, detailed studies using a high-speed camera have been used to investigate the droplet geometry and flight times. The robust mass transfer model of Weatherley and Petera has been utilized to correlate and predict the mass transfer rates for any geometry and any hydrodynamic regime based upon limited physical property and thermodynamic data.