Production of pure M-xylene and pure ethyl benzene from a mixture of C8 aromatic isomers

摘要

A process for separating a first component comprising meta- xylene, a second component comprising a mixture of para-xylene and ortho- xylene and a third component comprising ethyl benzene from a feedstream employing an adsorbent comprising a Y-zeolite containing sodium ions at exchangeable cationic sites and a desorbent material comprising toluene which in combination have selectivities for the first, second and third components, respectively, in descending order of magnitude. The process uses a simulated-moving bed counter current flow system with an intermediate raffinate stream taken off the column at about the midpoint of the adsorption zone in addition to the usual extract and raffinate product streams.