| Abstract: | Prevaporation through the PVA membrame containing β-cyclodextrin oligomer (PVA/CD membrane) was performed for the mixtures of water/ethanol, water/1-propanol, and water/2-propanol. At higher alcohol concentrations, the water selectivities were greatly increased by CD for all the mixtures, in the order of 2-propanol/water>1-propanol/water>ethanol/water. The water permeation rate was decreased by CD, and the alcohol permeation rate was decreased much more for each mixture. At lower alcohol concentrations, the water selectivity for 1-propanol/water was slightly increased by CD, and that for 2-propanol/water was scarcely affeted, whereas that for ethanol/water was greatly increased. The water permeation rate was increased by CD for each mixture, and the relative increases in the water rates for propanols/water were smaller than that for ethanol/water. The permeation rate of 1-propanol as well as that of ethanol was decreased by CD, but the rate of 2-propanol was was increased. These effects of CD can be explained in terms of the inclusion strength. © 1994 John Wiley & Sons, Inc. |
