| 摘要 |
The cost of separating para-xylene from other xylene isomers and C9 aromatics by adsorption on zeolitic molecular sieves is reduced by the use of certain relatively high boiling desorbents including 1,4 diisopropylbenzene. Preferably the adsorbent is an X zeolite adsorbent containing barium or both barium and potassium ions at exchangeable cationic sites. The para-xylene components are selectively adsorbed onto the adsorbent. The non-adsorbed feed is then removed from the adsorbent and the para-xylene recovered by desorption. Any C9 aromatic hydrocarbons and the other xylene isomers in the raffinate can be separated from these heavy desorbents by fractionation of the raffinate and the desorbent can be recycled to the process.
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