Phosphonium-based ionic liquids

Abstract

Quaternary phosphonium haloaluminate compounds according to Formula (I): wherein R 1 -R 3 are the same alkyl group; R 4 is different than R 1 -R 3 and is chosen from a C 4 -C 12 alkyl; and X is a halogen, are provided herein for use as an ionic liquid catalyst for reacting olefins and isoparaffins to generate an alkylate.

What is claimed is: 
     
         1 . A quaternary phosphonium haloaluminate compound according to Formula (I): 
       
         
           
           
               
               
           
         
         wherein
 R 1 -R 3  are the same alkyl group; 
 R 4  is different than R 1 -R 3  and is chosen from a C 4 -C 12  alkyl; and 
 
         X is a halogen. 
       
     
     
         2 . A compound according to Formula (I) of  claim 1 , wherein each of R 1 -R 3  is a C 3 -C 6  alkyl. 
     
     
         3 . A compound according to Formula (I) of  claim 2 , wherein each of R 1 -R 3  contain 4 carbon atoms. 
     
     
         4 . A compound according to Formula (I) of  claim 1 , wherein R 4  contains from 5 to 8 carbon atoms. 
     
     
         5 . A compound according to Formula (I) of  claim 4 , wherein R 4  is hexyl. 
     
     
         6 . A compound according to Formula (I) of  claim 1 , wherein X is selected from the group consisting of F, Cl, Br, and I. 
     
     
         7 . A compound according to Formula (I) of  claim 6 , wherein X is Cl. 
     
     
         8 . A compound according to Formula (I) of  claim 1 , wherein the quaternary phosphonium haloaluminate is selected from the group consisting of tripropylhexylphosphonium—Al 2 X 7 ; tributylpentylphosphonium—Al 2 X 7 ;
 tributylhexylphosphonium—Al 2 X 7 ; tributylheptylphosphonium—Al 2 X 7 ; 
 tributyloctylphosphonium—Al 2 X 7 ; tributylnonylphosphonium—Al 2 X 7 ; 
 tributyldecylphosphonium—Al 2 X 7 ; tributylundecylphosphonium—Al 2 X 7 ; and 
 tributyldodecylphosphonium—Al 2 X 7 , wherein X is selected from the group consisting of F, Cl, Br, and I. 
 
     
     
         9 . A compound according to Formula (I) of  claim 8 , wherein the quaternary phosphonium haloaluminate is tributylhexylphosphonium—Al 2 Cl 7 . 
     
     
         10 . A compound according to Formula (I) of  claim 8 , wherein the quaternary phosphonium haloaluminate is tri-n-butyl-hexylphosphonium—Al 2 Cl 7 . 
     
     
         11 . An ionic liquid catalyst for reacting olefins and isoparaffins to generate an alkylate, said catalyst comprising a quaternary phosphonium haloaluminate compound as defined in  claim 1 . 
     
     
         12 . An ionic liquid catalyst according to  claim 11 , wherein the catalyst has an initial kinematic viscosity of at least 50 cSt at a temperature of 20° C. 
     
     
         13 . An ionic liquid catalyst according to  claim 11 , wherein the catalyst has an initial kinematic viscosity of at least 20 cSt at a temperature of 50° C. 
     
     
         14 . An ionic liquid catalyst according to  claim 11 , wherein the boiling point at atmospheric pressure of HR4 of the phosphonium haloaluminate compound is at least 30° C. greater than the boiling point at atmospheric pressure of HR1. 
     
     
         15 . An ionic liquid catalyst according to  claim 11  further comprising a co-catalyst, wherein said ionic liquid catalyst is coupled with the co-catalyst. 
     
     
         16 . An ionic liquid catalyst according to  claim 15 , wherein the co-catalyst is a Bronsted acid selected from the group consisting of HCl, HBr, HI, and mixtures thereof. 
     
     
         17 . An ionic liquid catalyst according to  claim 16 , wherein said Bronsted acid co-catalyst is HCl. 
     
     
         18 . An ionic liquid catalyst according to  claim 11 , wherein the quaternary phosphonium haloaluminate is selected from the group consisting of tripropylhexylphosphonium—Al 2 X 7 ; tributylpentylphosphonium—Al 2 X 7 ; tributylhexylphosphonium—Al 2 X 7 ;
 tributylheptylphosphonium—Al 2 X 7 ; tributyloctylphosphonium—Al 2 X 7 ; 
 tributylnonylphosphonium—Al 2 X 7 ; tributyldecylphosphonium—Al 2 X 7 ; 
 tributylundecylphosphonium—Al 2 X 7 ; and tributyldodecylphosphonium—Al 2 X 7 , wherein X is selected from the group consisting of F, Cl, Br, and I. 
 
     
     
         19 . An ionic liquid catalyst according to  claim 18 , wherein the quaternary phosphonium haloaluminate is tributylhexylphosphonium—Al 2 Cl 7 . 
     
     
         20 . An ionic liquid catalyst according to  claim 18 , wherein the quaternary phosphonium haloaluminate is tri-n-butyl-hexylphosphonium—Al 2 Cl 7 .