| abstract |
In a process for producing para-xylene, a feed stream comprising C 6+ aromatic hydrocarbons is separated into a C 7− aromatic hydrocarbon-containing stream, a C 8 aromatic hydrocarbon-containing stream, and a C 9+ aromatic hydrocarbon-containing stream. The C 7− aromatic hydrocarbon-containing stream is contacted with a methylating agent to convert toluene to xylenes and produce a methylated effluent stream. Ethylbenzene is removed from the C 8 aromatic hydrocarbon-containing stream, para-xylene is recovered from the ethylbenzene-depleted C 8 aromatic hydrocarbon-containing stream and the methylated effluent stream in a para-xylene recovery section to produce a para-xylene depleted stream, which is then contacted with a xylene isomerization catalyst under liquid phase conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream. The C 9+ -containing stream with a transalkylation catalyst under conditions effective to convert C 9+ -aromatics to C 8− -aromatics and produce a transalkylated stream, which is recycled together with the isomerized stream to the para-xylene recovery section. |