ADSORPTION CHARACTERISTICS OF TOLUENE AND NAPHTHALENE ON SILICA-GEL UNDER THE SUBCRITICAL AND SUPERCRITICAL CONDITIONS USING CHROMATOGRAPHIC TECHNIQUES

Chromatographic techniques were used for measuring the adsorption of t oluene and naphthalene on silica gel packed beds under the supercritic al and subcritical conditions at 301-318 K, 54-150 atm, and 0.3<N-Re<7 . The moment method was used to determine the equilibrium constants an d rate parameters. The results showed a significant reduction of the a dsorption equilibrium constant as the pressure changed from subcritica l to supercritical; the axial dispersion coefficients at supercritical conditions were intermediate to those of what would be obtained in ga ses and liquids; in the pressure range where density fluctuations with concentration were large, axial dispersion was influenced by both nat ural convection and molecular diffusion; diffusion within the pores of the adsorbent was found to be the major resistance to adsorption, In addition to these parameters, partial molar volumes were determined fr om the chromatographic experiment and were found to agree well with th e values reported in earlier work.