S. Furutaka et S. Ikawa, Effect of temperature and pressure on a water-benzene mixture as studied by infrared spectroscopy, FLU PH EQUI, 185(1-2), 2001, pp. 379-387
A water-benzene mixture has been studied by infrared spectroscopy at temper
atures and pressures in the 473-648 K and 100-350 bar ranges. The OH stretc
hing band intensity has been obtained as a measure of water concentration i
n the mixture. In the temperature range of 473-523 K, the intensity is almo
st independent of pressure. On the contrary, at higher temperatures, the ab
sorption intensities exhibit remarkable pressure dependence. Moreover, the
intensities increase with increasing temperature towards a certain temperat
ure and then steeply decrease at higher temperatures. It has been found tha
t the turning points of the intensities are located on an extended line of
the liquid-liquid-gas three-phase equilibrium curve of the water-benzene mi
xture and near the critical curve between the two-phase and one-phase regio
ns. This fact suggests that density of the mixture changes steeply across t
hose lines. We have also observed coalescence of two bands, which are assig
ned to hydrogen-bonded and hydrogen-bond-free OH, respectively, at the high
er temperatures, and discussed rotational motion of a water molecule in a h
ydrogen-bonded cluster. (C) 2001 Elsevier Science B.V. All rights reserved.