Process for the separation of ethylbenzene by adsorption on cesium exchanged zeolite X

摘要

A separation process for ethylbenzene in mixtures with at least one other 8C aromatic hydrocarbon comprises contacting the mixt. at adsorption conditions (temp. 100 - 125[deg]C) with an caesium exchanged zeolite X adsorbent of silica:alumina ratio 2.0:1.0 - 2.3:1.0. The adsorbent selectively adsorbs the ethylbenzene, the remaining mixt. should be removed from contact with the adsorbent, from which the ethylbenzene may then be desorbed. Also claimed is a similar process for separating ethylbenzene from a mixt. with at least one other xylene, using a caesium-exchanged (present at more than 40 % of the zeolites exchangeable sites) zeolite adsorbent of silica:alumina ratio less than 2.2:1.0, and then desorbing the ethylbenzene from the adsorbent using a desorbent comprising an admixture of toluene and para-diethylbenzene at desorption conditions. Also claimed is a continuous separation process as above, using a zeolite exchanged with caesium at 50-60 % of the available sites and a silica:alumina ratio of 2.0. Desorption uses a desorbent comprising at least 25 % vol. toluene and 50 % vol. p-diethylbenzene. The desorbent pref. comprises 25 % vol. toluene and 50 % vol. p-diethylbenzene. The desorbent for the continuous process pref. comprises 30-50 % vol. toluene and 50-70 % vol. p-diethylbenzene. The pref. silica:alumina ratio for the zeolite used in the second process is 2.1:1.