Method for separating aromatic compounds contained in naphtha

Abstract

The present invention relates to a method for separating aromatic compounds contained in naphtha which includes an extraction step of contacting specific ionic liquids and naphtha and a step of separating the aromatic compounds from naphtha contacted with the ionic liquids.

1 . A method for separating aromatic compounds contained in naphtha which comprises the steps of: contacting naphtha with ionic liquids including one or more compounds selected from the group consisting of a bis-imidazolium-based ionic solvent, a bis-piperidinium-based ionic solvent, a bis-pyrrolidinium-based ionic solvent, a bis-morpholinium-based ionic solvent, a bis-imidazolium-based salt including an ether group, a bis-piperidinium-based salt including an ether group, a bis-pyrrolidinium-based salt including an ether group, and a bis-morpholinium-based salt including an ether group; and
 separating aromatic compounds from the naphtha contacted with the ionic liquids.   
     
     
         2 . The method for separating aromatic compounds contained in the naphtha of  claim 1  wherein:
 the bis-imidazolium-based salt including an ether group includes a cation in which two imidazolium-based rings are linked via a functional group including one or more ether groups having a total carbon number of 2 to 20, and a halide-based anion having hydrophobicity; 
 the bis-piperidinium-based salt including an ether group includes a cation in which two piperidinium-based rings are linked via a functional group including one or more ether groups having a total carbon number of 2 to 20, and a halide-based anion having hydrophobicity; 
 the bis-pyrrolidinium-based salt including an ether group includes a cation in which two pyrrolidinium-based rings are linked via a functional group including one or more ether groups having a total carbon number of 2 to 20, and a halide-based anion having hydrophobicity; and 
 the bis-morpholinium-based salt including an ether group includes a cation in which two morpholinium-based rings are linked via a functional group including one or more ether groups having a total carbon number of 2 to 20, and a halide-based anion having hydrophobicity. 
 
     
     
         3 . The method for separating aromatic compounds contained in the naphtha of  claim 1  wherein
 the bis-imidazolium-based salt including an ether group includes a compound represented by Formula 1 below, 
 the bis-piperidinium-based salt including an ether group includes a compound represented by Formula 2 below, 
 the bis-pyrrolidinium-based salt including an ether group includes a compound represented by Formula 3 below, and 
 the bis-morpholium-based salt including an ether group includes a compound represented by Formula 4 below: 
 
       
         
           
           
               
               
           
         
         in the above Formula 1, R 1  and R 1 ′ may be the same as or different from each other and are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl group having 1 to 10 carbon atoms, R 2 , R 2 ′, R 3 , R 3 ′, R 4 , and R 4 ′ may be the same as or different from each other and are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl group having 1 to 10 carbon atoms, 
         Y is (CF 3 SO 2 ) 2 N − , BF 4− , or PF 6   − , and 
         X is the following Formula 1a or Formula 1b:
   R ak1 —O—R ak2  n    [Formula 1a]
 
   R ak1 —O n —R ak2 —  [Formula 1b]
 
 
         in the Formula 1a or Formula 1b, R ak1  and R ak2  are each independently a linear or branched alkylene group having 1 to 10 carbon atoms, and n is an integer from 1 to 5; 
       
       
         
           
           
               
               
           
         
         in the above Formula 2, 
         R 1  and R 1 ′ may be the same as or different from each other and are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl group having 1 to 10 carbon atoms, R 2 , R 2 ′, R 3 , R 3 ′, R 4 , R 4 ′, R 5 , R 5 ′, R 6 , and R 6 ′ may be the same as or different from each other and are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl group having 1 to 10 carbon atoms, 
         Y is (CF 3 SO 2 ) 2 N − , BF 4− , or PF 6   − , and 
         X is the following Formula 2a or Formula 2b:
   R ak1 —O—R ak2  n    [Formula 2a]
 
   R ak1 —O n —R ak2 —  [Formula 2b]
 
 
         in the above Formula 2a or Formula 2b, R ak1  and R ak2  are each independently a linear or branched alkylene group having 1 to 10 carbon atoms, and n is an integer from 1 to 5; 
       
       
         
           
           
               
               
           
         
         in the above Formula 3, 
         R 1  and R 1 ′ may be the same as or different from each other and are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl group having 1 to 10 carbon atoms, R 2 , R 2 ′, R 3 , R 3 ′, R 4 , R 4 ′, R 5 , and R 5 ′ may be the same as or different from each other and are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl group having 1 to 10 carbon atoms, 
         Y is (CF 3 SO 2 ) 2 N − , BF 4− , or PF 6   − , and 
         X is the following Formula 3a or Formula 3b:
   R ak1 —O—R ak2  n    [Formula 3a]
 
   R ak1 —O n —R ak2 —  [Formula 3b]
 
 
         in the above Formula 3a or Formula 3b, R ak1  and R ak2  are each independently a linear or branched alkylene group having 1 to 10 carbon atoms, and n is an integer from 1 to 5; 
       
       
         
           
           
               
               
           
         
         in the above Formula 4, 
         R 1  and R 1 ′ may be the same as or different from each other and are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl group having 1 to 10 carbon atoms, R 2 , R 2 ′, R 3 , R 3 ′, R 4 , R 4 ′, R 5 , and R 5 ′ may be the same as or different from each other and are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl group having 1 to 10 carbon atoms, 
         Y is (CF 3 SO 2 ) 2 N − , BF 4− , or PF 6   − , and 
         X is the following Formula 4a or Formula 4b:
   R ak1 —O—R ak2  n    [Formula 4a]
 
   R ak1 —O n —R ak2 —  [Formula 4b]
 
 
         in the above Formula 4a or Formula 4b, R ak1  and R ak2  are each independently a linear or branched alkylene group having 1 to 10 carbon atoms, and n is an integer from 1 to 5. 
       
     
     
         4 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the bis-imidazolium-based ionic solvent includes one or more compounds selected from the group consisting of 1,1′-(1,2-ethanediyl)bis(3-methylimidazolium)bis(trifluoromethanesulfonyl)imide, 1,1′-(1,4-butanediyl)bis(3-ethylimidazolium)bis(trifluoromethane sulfonyl)imide, 1,1′-(2,4′-butenediyl)bis(3-butylimidazolium)bis(trifluoromethanesulfonyl)imide, 1,1′-(1,4-butanediyl-2-one)bis(3-ethylimidazolium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl-2,3-dione)bis(3-butylimidazolium)bis(trifluoromethanesulfonyl)imide, 1,1′-(1,4-butanediyl-2-ol)bis(3-methylimidazolium)bis(trifluoro methanesulfonyl)imide, and 1,1′-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,2-ethanediyl)bis(3-methylimidazolium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl)bis(3-ethylimidazolium)bis(tetrafluoroborate), 1,1′-(2,4-betenediyl)bis(3-butylimidazolium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2-one)bis(3-ethylimidazolium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2,3-dione)bis(3-ethylimidazolium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2-ol)bis(3-ethylimidazolium)bis(tetrafluoroborate), and 1,1′-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(tetrafluoroborate), 1,1′-(1,2-ethanediyl)bis(3-methylimidazolium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl)bis(3-ethylimidazolium)bis(hexafluorophosphate), 1,1′-(2,4-butenediyl)bis(3-butyl-imidazolium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl-2-pyridyl)bis(3-ethylimidazolium)bis(hexamethylene fluorophosphate), 1,1′-(1,4-butanediyl-2,3-dione)bis(3-butylimidazolium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl-2-ol)bis(3-ethylimidazolium)bis(hexafluorophosphate), and 1,1′-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(hexafluorophosphate).   
     
     
         5 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the bis-pyrrolidinium-based ionic solvent includes one or more compounds selected from the group consisting of 1,1′-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl)bis(1-butylpyrrolidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(2,3-butendiyl)bis(1-ethylpyrrolidinium)bis(trifluoromethanesulfonyl)imide, 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl)bis(1-butylpyrrolidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate), 1,1′-(2,3-butenediyl)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(hexafluorophosphate), 1,1′-(4-butanediyl)bis(1-butylpyrrolidinium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(hexafluorophosphate), 1,1′-(2,3-butenediyl)bis(1-ethylpyrrolidinium)bis(hexafluorophosphate), and 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(hexafluorophosphate);   the bis-morpholinium-based ionic so vent includes one or more compounds selected from the group consisting of 1,1′-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl)bis(1-butylmorpholinium)bis(trifluoro methane sulfonyl)imide, 1,1′-(1,4-butanediyl-2-ol)bis(1-ethylmorpholinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethylmorpholinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(2,3-butenediyl)bis(1-ethylmorpholinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(trifluoro methane sulfonyl)imide, 1,1′-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl)bis(1-butylmorpholinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2-ol)bis(1-ethylmorpholinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethylmorpholinium)bis(tetrafluoroborate), 1,1′-(2,3-butenediyl)bis(1-ethylmorpholinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl)bis(1-butylmorpholinium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl-2-ol)bis(1-ethyl-morpholinium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethylmorpholinium)bis(hexafluorophosphate), 1,1′-(2,3-butendiyl)bis(1-ethylmorpholinium)bis(hexafluorophosphate), and 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(hexafluorophosphate); and   the bis-piperidinium-based ionic solvent includes one or more compounds selected from the group consisting of 1,1′-(1,4-butanediyl)bis(1-ethylpiperidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl)bis(1-butylpiperidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl-2-ol)bis(1-ethyl-piperidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethylpiperidinium)bis(trifluoro methane sulfonyl)imide, 1,1′-(2,3-butanediyl)bis(1-ethylpiperidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(trifluoromethane sulfonyl)imide, 1,1′-(4-butanediyl)bis(1-ethylpiperidinium)bis(tetrafluoroborate), 1,1′-(1,4-butandiyl)bis(1-butylpiperidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2-ol)bis(1-ethylpiperidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethyl-piperidinium)bis(tetrafluoroborate), 1,1′-(2,3-butenediyl)bis(1-ethylpiperidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(tetrafluoroborate), 1,1′-(1,4-butanediyl)bis(1-ethylpiperidinium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl)bis(1-butylpiperidinium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl-2-ol)bis(1-ethylpiperidinium)bis(hexafluorophosphate), 1,1′-(1,4-butanediyl-2,3-diol)bis(1-ethylpiperidinium)bis(hexafluorophosphate), 1,1′-(2,3-butenediyl)bis(1-ethylpiperidinium)bis(hexafluorophosphate), and 1,1′-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(hexafluorophosphate).   
     
     
         6 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the naphtha is used in an amount of 0.05 to 5% by volume compared to the ionic liquids.   
     
     
         7 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the step of contacting the ionic liquid and naphtha is conducted at a temperature of 20° C. to 100° C.   
     
     
         8 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the step of contacting the ionic liquids and naphtha is conducted for 1 min or more.   
     
     
         9 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the step of contacting the ionic liquids and naphtha is conducted for 30 min to 10 h.   
     
     
         10 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the step of separating aromatic compounds from naphtha contacted with the ionic liquids is conducted at least once.   
     
     
         11 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the step of separating aromatic compounds from naphtha contacted with the ionic liquids includes a step for conducting the separation by a liquid-liquid extraction method.   
     
     
         12 . The method for separating aromatic compounds contained in the naphtha of  claim 1 , which further comprises a step for separating a raffinate obtained in the extraction step. 
     
     
         13 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the step of separating aromatic compounds from naphtha contacted with the ionic liquids further comprises a step of conducting deaeration at a temperature of 20 to 150° C. and a pressure of 1 to 200 mmHg.   
     
     
         14 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the extraction step is performed in a pulsed extraction column.   
     
     
         15 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the pulsation is introduced at a velocity of 10 m/s to 60 m/s in the pulsed extraction column.   
     
     
         16 . The method for separating aromatic compounds contained in the naphtha of  claim 1 , which further comprises the steps of introducing the extraction solvent into the upper end of the pulsed extraction column, and introducing the naphtha into the lower end of the pulsed extraction column. 
     
     
         17 . The method for separating aromatic compounds contained in the naphtha of  claim 1 ,
 wherein the step of separating aromatic compounds from naphtha contacted with the ionic liquids is a step of conducting the separation by a liquid-liquid extraction method.