title: Anomalous volumetric behavior of water-hexane and water-decane mixtures in the vicinity of the critical region as studied by infrared spectroscopy.
abstract: Infrared spectra of binary mixtures of water with hexane and decane were measured at temperatures and pressures in the 473-648 K and 70-350 bar ranges, respectively. Volumetric concentrations of water and the hydrocarbons in the mixtures were obtained from absorption intensities of the fundamental OH stretching band of HDO and combination transitions of the hydrocarbons. Using both the concentrations, densities of the aqueous mixtures were estimated and compared with densities before mixing, which were calculated using literature densities of the neat liquids. It is found that anomalously large volume expansion on mixing occurs in the vicinity of the critical region of the mixtures.
authors.affiliation: Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Sigenori
authors.initials: S
authors.lastname: Arai
authors.forename: Seiya
authors.initials: S
authors.lastname: Furutaka
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Ikawa