SEPARATION OF LIQUID-MIXTURES OF PARAXYLENE AND ORTHOXYLENE IN X-ZEOLITES - THE ROLE OF WATER-CONTENT ON THE ADSORBENT SELECTIVITY

The selectivity and purity enhancement related to the separation of the isomers p-xylene and o-xylene were studied on a laboratory unit using the liquid-phase adsorption in fixed beds containing zeolite type X whose cation Na+ was replaced by Ba2+ and K+. Using adsorbents with preestablished contents of water and prepared on a special laboratory setup, experiments of the type stimulus-response using the technique of pulses were conducted, being aimed at the determination of the selectivities on the separation of p-xylene from mixtures with ethylbenzene and also on the separation of p-xylene from mixtures with o-xylene. It is shown that an optimum water content in X zeolites with a value around 3.25 wt % occurs for the selectivity in separating p-xylenes and o-xylenes. Concluding the work, we verified that it is possible to obtain with a good yield p-xylene from a stream of isomers through adsorption in zeolite type X in the liquid phase and that the developed methodology gave precise and repetitive results.