Catalytic disproportionation of butane using ionic liquids

Abstract

Processes for the disproportionation and isomerization of a C 4 hydrocarbon feed using a liquid catalyst comprising an ionic liquid and a carbocation promoter are described. The ionic liquid is unsupported, and the reactions occur at temperatures below about 300° C.

What is claimed is: 
     
         1 . A hydrocarbon conversion process comprising:
 disproportionating a hydrocarbon feed comprising normal C 4  alkane or branched C 4  alkane by contacting the hydrocarbon feed with a liquid catalyst in a reaction zone under disproportionation conditions to form a product mixture comprising at least about 0.2 wt % C 3−  alkanes and C 5+  alkanes in 1 hr based on the C 4  alkanes in the hydrocarbon feed, wherein the liquid catalyst comprises an unsupported ionic liquid and a carbocation promoter, and wherein a mass ratio of liquid catalyst to hydrocarbon feed is less than 0.75:1.   
     
     
         2 . The process of  claim 1  wherein the ionic liquid comprises an organic cation and an anion. 
     
     
         3 . The process of  claim 2  wherein the organic cation is selected from the group consisting of: 
       
         
           
           
               
               
           
         
       
       where R 1 -R 21  are independently selected from C 1 -C 20  hydrocarbons, C 1 -C 20  hydrocarbon derivatives, halogens, and H. 
     
     
         4 . The process of  claim 2  wherein the anion is derived from halides, sulfates, bisulfates, nitrates, sulfonates, fluoroalkanesulfonates, or combinations thereof. 
     
     
         5 . The process of  claim 2  wherein the anion is selected from the group consisting of AlCl 4   − , Al 2 Cl 7   − , Al 3 Cl 10   − , AlCl 3 Br − , Al 2 Cl 6 Br − , Al 3 Cl 9 Br − , AlBr 4   − , Al 2 Br 7   − , Al 3 Br 10   − , GaCl 4   − , Ga 2 Cl 7   − , Ga 3 Cl 10   − , GaCl 3 Br − , Ga 2 Cl 6 Br − , Ga 3 Cl 9 Br − , CuCl 2   − , Cu 2 Cl 3   − , Cu 3 Cl 4   − , ZnCl 3   − , FeCl 3   − , FeCl 4   − , Fe 3 Cl 7   − , PF 6   − , and BF 4   − . 
     
     
         6 . The process of  claim 1  wherein the carbocation promoter comprises a haloalkane, a mineral acid, or combinations thereof. 
     
     
         7 . The process of  claim 6  wherein the carbocation promoter comprises the haloalkane, and wherein the haloalkane comprises 2-chloro-2-methylpropane, 2-chloropropane, 2-chlorobutane, 2-chloro-2-methylbutane, 2-chloropentane, 1-chlorohexane, 3-chloro-3-methylpentane, or combinations thereof. 
     
     
         8 . The process of  claim 6  wherein the carbocation promoter comprises the mineral acid, and wherein the mineral acid comprises HCl. 
     
     
         9 . The process of  claim 1  further comprising stirring the hydrocarbon feed and the liquid catalyst while contacting the hydrocarbon feed with the liquid catalyst. 
     
     
         10 . The process of  claim 1  wherein a molar ratio of the carbocation promoter to ionic liquid is in a range of about 0:1 to about 3:1. 
     
     
         11 . The process of  claim 1  further comprising separating the ionic liquid from the product mixture. 
     
     
         12 . The process of  claim 11  further comprising regenerating the separated ionic liquid. 
     
     
         13 . The process of  claim 1  further comprising: drying the hydrocarbon feed before contacting the hydrocarbon feed with the liquid catalyst; or treating the hydrocarbon feed to remove one or more of alkenes, dienes, or nitriles; or both. 
     
     
         14 . The process of  claim 1  wherein a concentration of acid in the ionic liquid is less than about 2.5 M. 
     
     
         15 . The process of  claim 1  further comprising isomerizing the hydrocarbon feed concurrently with disproportionating the hydrocarbon feed. 
     
     
         16 . The process of  claim 15  wherein the product mixture has a ratio of branched C 4  alkane to normal C 4  alkane of at least about 0.3 in 1 hr. 
     
     
         17 . The process of  claim 1  wherein the hydrocarbon feed comprises a mixture of at least C 4  and C 5  alkanes. 
     
     
         18 . The process of  claim 1  wherein the product mixture further comprises at least about 0.3 wt % C 3−  alkanes and C 5+  alkanes in 1 hr based on the C 4  alkanes in the hydrocarbon feed. 
     
     
         19 . The process of  claim 1  wherein the product mixture comprises at least about 0.5 wt % C 3−  alkanes and C 5+  alkanes in 8 hr based on the C 4  alkanes in the hydrocarbon feed. 
     
     
         20 . The process of  claim 1  wherein the product mixture comprises at least about 1 wt % C 3−  alkanes and C 5+  alkanes in 25 hr based on the C 4  alkanes in the hydrocarbon feed.