Extractive Distillation of Isobutyl Alcohol and Isobutyl Acetate Using Dimethyl Sulfoxide: Process Design and Intensification

Abstract

We have designed a separation process of isobutyl alcohol (52.0 mol%) and isobutyl acetate (48.0 mol%) mixture using conventional extractive distillation (ED) and extractive dividing-wall column (E-DWC) with the solvent dimethyl sulfoxide (DMSO). The binary mixture exhibits a minimum boiling azeotrope that is sensitive to pressure. Thermodynamic analyses have shown that the vacuum pressures work better compared to the atmospheric pressure when DMSO is the solvent. Based on the separation with a purity of 99.9 mol%, the E-DWC process has resulted in 9.6 % and 4.8 % reductions in the total annual cost and CO₂ emission rates, respectively, in comparison to the conventional method. After further intensification using the heat pump technique, the E-DWC process with the solvent DMSO has provided more than 40.0 % reduction in energy consumption compared to the ED systems studied in the literature using the solvents butyl propionate and dimethylformamide.