US 9,809,509 B2
Process for xylenes isomerization
Brian M. Weiss, Bridgewater, NJ (US); Darryl D. Lacy, Easton, PA (US); and Scott J. Weigel, Allentown, PA (US)
Assigned to ExxonMobil Chemical Patents Inc., Baytown, TX (US)
Filed by ExxonMobil Chemical Patents Inc., Baytown, TX (US)
Filed on Oct. 18, 2016, as Appl. No. 15/296,878.
Claims priority of provisional application 62/267,428, filed on Dec. 15, 2015.
Prior Publication US 2017/0166498 A1, Jun. 15, 2017
Int. Cl. C07C 5/27 (2006.01); C07C 4/18 (2006.01)
CPC C07C 5/2737 (2013.01) [C07C 4/18 (2013.01); C07C 2529/40 (2013.01); C07C 2529/70 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A process for producing para-xylene from a C8 aromatic hydrocarbon mixture, the process comprising:
(a) providing a C8 aromatic hydrocarbon mixture comprising para-xylene, ortho-xylene and meta-xylene to an ortho-xylene splitter to produce a first stream comprising para-xylene and meta-xylene and a second stream comprising ortho-xylene;
(b) passing the first stream comprising para-xylene and meta-xylene to a para-xylene recovery unit to recover a para-xylene product stream and produce a para-xylene-depleted stream consisting essentially of meta-xylene;
(c) contacting the para-xylene-depleted stream comprising meta-xylene with a catalyst under at least partially liquid phase conditions effective to produce a first isomerized stream having a para-xylene content of more than 24 wt.%, based on the total amount of xylenes in the first isomerized stream; and first isomerized stream, wherein the catalyst comprises ZSM-23 with a SiO2/A12O3 ratio between 15 and 50 and an external surface area of 75-115 m2/g; and
(d) recycling at least a portion of the first isomerized stream back to the para-xylene recovery unit.