PROCESS TO REMOVE DISSOLVED AlCl3 FROM IONIC LIQUID

Abstract

Disclosed herein are processes in which precipitation permits removal of metal halides (e.g. AlCl 3 ) from ionic liquids. After precipitation, the precipitated metal halides can be physically separated from the bulk ionic liquid. More effective precipitation can be achieved through cooling or the combination of cooling and the provision of metal halide seed crystals. The ionic liquids can be regenerated ionic liquid catalysts, which contain excess metal halides after regeneration. Upon removal of the excess metal halides, they can be reused in processes using ionic liquid catalysts, such as alkylation processes.

That which is claimed is: 
     
         1 . A process for regenerating an ionic liquid catalyst, comprising:
 a) reacting an ionic liquid catalyst with aluminum to provide a regenerated ionic liquid catalyst containing excess dissolved AlCl 3 ;   b) precipitating the excess dissolved AlCl 3  from the regenerated ionic liquid catalyst to provide precipitated excess AlCl 3 , and   c) removing the precipitated excess AlCl 3  from the regenerated ionic liquid catalyst.   
     
     
         2 . The process according to  claim 1 , further comprising cooling the regenerated ionic liquid catalyst to precipitate excess dissolved AlCl 3  from the regenerated ionic liquid catalyst. 
     
     
         3 . The process according to  claim 2 , wherein the cooling step provides AlCl 3  seed crystals 
     
     
         4 . The process according to  claim 1 , further comprising separating the precipitated excess AlCl 3  by filtration. 
     
     
         5 . The process according to  claim 1 , further comprising separating the precipitated excess AlCl 3  by decantation. 
     
     
         6 . The process according to  claim 1 , wherein the mixture is cooled to a temperature less than about 50° C. to precipitate the excess dissolved AlCl 3 . 
     
     
         7 . The process according to  claim 1 , wherein the mixture is cooled to about room temperature or to less than about room temperature to precipitate the excess dissolved AlCl 3 . 
     
     
         8 . The process according to  claim 1 , further comprising:
 feeding the regenerated ionic liquid catalyst containing excess dissolved AlCl 3  to a vessel and providing AlCl 3  seed crystals to provide a mixture comprising the regenerated ionic liquid catalyst, dissolved AlCl 3 , and AlCl 3  seed crystals; and   cooling the mixture in the vessel to precipitate the excess dissolved AlCl 3 .   
     
     
         9 . An alkylation process, comprising:
 a) conducting an alkylation reaction with an ionic liquid catalyst to provide a product and a spent ionic liquid catalyst;   b) reacting the spent ionic liquid catalyst with aluminum to provide a regenerated ionic liquid catalyst and excess dissolved AlCl 3 ;   c) precipitating the excess dissolved_AlCl 3  from the regenerated ionic liquid catalyst to provide precipitated excess AlCl 3 ;   d) removing the precipitated excess AlCl 3  from the regenerated ionic liquid catalyst; and   e) recycling the regenerated ionic liquid catalyst to reaction step a).   
     
     
         10 . The process according to  claim 9 , further comprising removing the precipitated excess AlCl 3  by filtration. 
     
     
         11 . The process according to  claim 9 , further comprising removing the precipitated excess AlCl 3  by decantation. 
     
     
         12 . The process according to  claim 9 , wherein the mixture is cooled to a temperature less than about 50° C. to precipitate the excess dissolved AlCl 3 . 
     
     
         13 . The process according to  claim 9 , wherein the mixture is cooled to about room temperature or to less than about room temperature to precipitate the excess dissolved AlCl 3 .