Kinetics of sorption of 1,3 di-isopropyl benzene and 1,3,5 tri-isopropyl benzene in nay crystals, alumina matrix and FCC catalyst particles by zero length column method

The kinetics of sorption of 1,3 di-isopropyl benzene and 1,3,5 tri isopropyl benzene in NaY crystals, alumina matrix particles and FCC catalyst particles is reported. Both molecules were found to have highly nonlinear equilibrium adsorption properties in all three adsorbents and the observed K values are approximately 105. In NaY crystals, the desorption curve of 1,3 di-isopropyl benzene was normal, but that for 1,3,5 tri-isopropyl benzene contained a discontinuity reminiscent of a percolation threshold. The diffusivities in NaY crystals were micropore controlled and were determined from the nonlinear asymptotic form of the ZLC model. The alumina matrix particles, scanned by SEM to determine their size distribution, were macropore controlled in agreement with theory for 1,3,5 tri-isopropyl benzene. The FCC catalyst which is composed of 80 % alumina matrix and 20 % NaY crystals results are intriguing. The short term desorption appears macropore controlled. The long term diffusion asymptotes are identical for both sorbates to that for NaY crystals indicating micropore control but are significantly displaced due to the adsorption on the alumina matrix.