Process for separating para-xylene from a C.sub.8 and C.sub.9 aromatic mixture

A process for the production and recovery of para-xylene from an aromatic feed stream comprising C.sub.8 aromatic hydrocarbons and up to about 25% (wt.) C.sub.9 aromatic hydrocarbons comprising the steps of:

• (a) contacting said feed stream with an adsorbent selective for para-xylene and relatively less selective for the other C.sub.8 aromatic hydrocarbons in a separation zone;
• (b) removing a raffinate stream comprising the less selectively adsorbed feed components and desorbent from contact with said adsorbent;
• (c) contacting said adsorbent with a heavy desorbent having 10 to 12 carbon atoms, at desorption conditions, to effect the removal of an extract stream comprising para-xylene, C.sub.9 aromatic hydrocarbons and desorbent;
• (d) fractionating said extract stream in an extract fractionator to produce an extract overhead stream comprising para-xylene, a sidecut stream comprising substantially all of said C.sub.9 aromatics in said extract and a minor amount of the desorbent in said extract stream and an extract bottoms stream comprising a major amount of the desorbent in said extract stream;
• (e) fractionating said raffinate stream and said sidecut stream in a raffinate fractionator to produce a raffinate overhead stream comprising said less selectively adsorbed C.sub.8 isomers and C.sub.9 aromatics and a bottoms stream comprising desorbent;
• and
• (f) recovering para-xylene from said extract overhead stream.