Dw. Jin et al., A STUDY ON THE ADSORPTION CHARACTERISTICS OF ACETONE AND BENZENE IN SUPERCRITICAL CARBON-DIOXIDE MEASURED BY CHROMATOGRAPHY AND IR SPECTROSCOPY, Bulletin of the Chemical Society of Japan, 70(12), 1997, pp. 2987-2993
Chromatographic and FTIR techniques were applied to a study of the abs
orption characteristics of acetone and benzene on a silica gel (SG800)
in supercritical CO2 at 313.2 and 333.2 K. The chromatographic isothe
rms for acetone and benzene have a maximum at a pressure lower than th
e critical pressure of CO2, and then decrease with increasing pressure
. When the temperature increases, the adsorption isotherms decrease in
the low-pressure region, and increase in the high-pressure region, pr
oviding a crossover at a relatively high pressure. The elution curves
of acetone showed tailing, even at high pressures, while those of benz
ene showed quasi-Gaussian curves at high pressures. The tailing curves
for acetone indicate the existence of heterogeneous sites; evidence o
f hydrogen-bonding formation with surface silanol groups has been prov
ided by IR spectroscopy.