Isobaric Vapor-Liquid Equilibria for Ternary Systems Acetone plus Ethanol+1-Butanol and Ethanol+1-Butanol+2-Ethyl-1-hexanol and Their Constituent Binary Systems

Experimental isobaric vapor-liquid equilibrium (VLE) data at 101.3 kPa were obtained for the development of purification processes for biobutanol. We focused on hybrid configurations using a combination of liquid-liquid extraction and distillation alternatives for the biobutanol purification, i.e., the separation of the product into raffinate and extract phases using liquid-liquid extraction and distillation for the recovery of the extractant, acetone, butanol, and ethanol. We used 2-ethyl-1-hexanol as the extractant for liquid-liquid extraction. Two ternary systems, i.e., acetone + ethanol + 1-butanol and ethanol + 1-butanol + 2-ethyl-1-hexanol, and their six constituent binary systems were studied at 101.3 kPa. The binary VLE data were represented by using the Wilson, NRTL, and UNIQUAC models. The ternary VLE data were compared with the predicted data using the binary parameters of these models obtained from the experimental VLE data of the constituent binary systems, and good prediction accuracy was obtained. Two group contribution methods, i.e., modified UNIFAC (Dortmund) and ASOG, were also used for VLE prediction for the binary and ternary systems.