Para-Xylene Selective Adsorbent Compositions and Methods

Abstract

Adsorbent compositions for vapor-phase adsorption processes, which are selective for para-xylene. Such compositions can be used in gas-phase adsorption processes for the separation of para-xylene or the separation of para-xylene and ethylbenzene from mixed xylenes or a C 8 aromatic mixture, respectively. The adsorbent compositions generally comprise materials of a molecular sieve material and a binder, wherein the adsorbent composition has a macropore volume of at least about 0.02 cc/g and a mesopore volume of less than about 0.20 cc/g.

1 - 69 . (canceled) 
     
     
         70 . A method comprising:
 (a) contacting a mixture comprising xylene isomers with a para-xylene selective adsorbent comprising a molecular sieve material and a binder; and   (b) desorbing from the para-xylene selective adsorbent an effluent comprising a para-xylene enriched product,   
       wherein the adsorbent has a macropore volume of at least about 0.20 cc/g and a mesopore volume of less than about 0.20 cc/g. 
     
     
         71 . The method of  claim 70 , wherein step (a) further comprises contacting the mixture with the adsorbent to obtain a para-xylene depleted raffinate. 
     
     
         72 . The method of  claim 71 , further comprising isomerizing at least a portion of the para-xylene depleted raffinate to obtain a hydrocarbon mixture comprising equilibrated xylene isomers. 
     
     
         73 . The method of  claim 72 , further comprising combining at least a portion of the hydrocarbon mixture comprising equilibrated xylene isomers with the mixture comprising xylene isomers. 
     
     
         74 . The method of  claim 70 , wherein the mixture is a gaseous mixture. 
     
     
         75 . The method of  claim 74 , wherein the contacting step is carried out at an operating temperature between about 145° C. and about 400° C. 
     
     
         76 . The method of  claim 74 , wherein the contacting step is carried out at an operating pressure between about 345 kPa and about 6895 kPa. 
     
     
         77 . The method of  claim 74 , wherein the desorbing step comprises feeding a sweep gas into a bed. 
     
     
         78 . The method of  claim 77 , wherein the desorbing step is carried out at an operating temperature between about 145° C. and about 400° C. 
     
     
         79 . The method of  claim 77 , wherein the desorbing step is carried out at an operating pressure between about 345 kPa and about 6895 kPa.