Separation of p-xylene from C8 aromatics On binder-free hydrophobic adsorbent of MFI zeolite.: I.: Studies on static equilibrium

The static equilibrium of Cx aromatics in liquid phase was studied on a binder-free MFI zeolite adsorbent, which possesses perfect framework and high hydrophobicity. The selectivity factor for para-xylene/ethylbenzene and paraxylene/ortho-xylene is determined as 7.95 and 104, respectively. A series of desorbents matched with adsorbents such as benzene, toluene, butylbenzene, monochlorobenzene, para-diethylbenzene and para-dichlorobenzene were investigated as well. The adsorbent can be regenerated and used without controlling the content of water. The isotherms for each isomer of C-8 aromatics and the desorbents possess the adsorption characteristics of Langmuir type. The saturation adsorption capacities of the adsorbates were determined. Unusually, no adsorption of meta-xylene on the adsorbent was found, which is much different from those observed on the zeolite of ZSM-5. The competitive adsorption curves of the multi-component feed were also investigated. The high shape selectivity of separation is related to the perfect structure of the adsorbent. (C) 2000 Elsevier Science B.V. All rights reserved.