The isobaric vapor-liquid equilibria of the binary 1-propanol + water, 2-propanol + water, and 2-methyl-2-propanol (tert-butanol) + water systems were predicted using the conductor-like screening model for realistic solvation (COSMO-RS) method. The phase behavior of the 1-propano1/2-propanol/tert-butanol water + piperazine-based Good's buffer systems were predicted. The effect of piperazine-containing Good's buffers, 2-[4-(2-hydroxyethyl)piperazin-1-yl]alkanesulfonic acid, as mass-separating agents on the separation of proponals from water were discussed. The influence of alkyl chain length between the zwitterion end groups, R = methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl was evaluated. Further, the effect of 4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropane sulfonic acid) was also evaluated. Piperazine-based Good's buffers are expected to be effective mass separating agents to have practical application in the separation of propanol from water. (C) 2016 Elsevier B.V. All rights reserved.