Patent ID: 7091389

Claim:
A method for separating an aromatic compound isomer substituted with alkyl group(s) and/or halogen atom(s) comprising subjecting a starting mixture containing the aromatic compound isomer to adsorptive separation by the use of a zeolite-containing adsorbent and a desorbent, subjecting the desorbent, after it has been collected from the adsorptive separation, to a method selected from the group consisting of distillation, purging, and adsorption to a solid adsorbent to achieve a level of impurities below 1,000 ppm by weight, the impurities being selected from the group consisting of water, hydrochloric acid, phenols, dimers of aromatic compounds, unsaturated hydrocarbon-containing compounds and oxygen-containing compounds, and after having been processed to remove impurities, supplying the desorbent to the adsorptive separation step and collecting the separated aromatic compound isomer.