Ionic liquids based on imidazolium salts incorporating a nitrile functionality

Abstract

Novel chemical compounds of the general formula K+A− useful as industrial solvents, especially as ligands, for efficient catalyst recycling.

1 . Chemical compounds of the general formula,
   K + A − ,   
       in which K +  is a 5- or 6-membered heterocyclic ring having 1-3 hetero atoms, which can be independently N, S, or O;
 with the proviso that at least one of the hetero atoms must be a quaternized nitrogen atom having a —R′CN substituent, wherein R′ is alkyl (C 1  to C 12 ); 
 the heterocyclic ring having up to 4 or 5 substituents independently chosen from the moieties:
 (i) H; 
 (ii) halogen or 
 (iii) alkyl (C 1  to C 12 ), which is unsubstituted or partially or fully substituted by further groups, preferably F, Cl, N(C n F (2n+1−x) H x ) 2 , O(C n F (2n+1−x) H x ), SO 2 (C n F (2n+1−x) H x ) 2  or C n F (2n+1−x) H x  where 1<n<6 and 0<x<13; and 
 
 (iv) a phenyl ring which is unsubstituted or partially or fully substituted by further groups, preferably F, Cl, N(C n F (2n+1−x) H x ) 2 , O(C n F (2n+1−x) H x ), SO 2 (C n F (2n+1−x) H x ) 2  or C n F (2n+1−x) H x  where 1<n<6 and 0<x≦13; and 
 A −  is halide, such as chloride, bromide, fluoride and the like; BF 4   − , PF 6   − , NO 3   − , CH 3 CO 2   − , CF 3 SO 3   − , (CF 3 SO 2 ) 2 N − , (CF 3 SO 2 ) 3 C − , CF 3 CO 2   −  or N(CN) 2   − . 
 
     
     
         2 . The compound of  claim 1  in which the heterocyclic ring is the pyrrolium, pyrazolium, pyridinium, pyrazinium, pyrimidinium, pyrazinium, imidazolium, thiazolium, oxazolium, or triazolium. 
     
     
         3 . The compound of  claim 2  in which the heterocyclic ring is the pyridinium or imidazolium. 
     
     
         4 . The compound of  claim 1  in which the anion is chloride. 
     
     
         5 . The compound of  claim 1  in which the anion is BF 4  or PF 6 . 
     
     
         6 . The compound of  claim 1  complexed with PdClwhich the anion is BF 4 . 
     
     
         7 . The compound of  claim 1  complexed with PdCl 2 , PtCl 2 , RuCl 3 , RhCl 3 , or [Ru(arene)Cl 2 ] 2 .