Poly(Ionic Liquid) Sorbents and Membranes for CO2 Separation

Abstract

Polymerizable ionic liquid monomers and their corresponding polymers (poly(ionic liquid)s) are created and found to exhibit high CO 2 sorption. The poly(ionic liquid)s have enhanced and reproducible CO 2 sorption capacities and sorption/desorption rates relative to room-temperature ionic liquids. Furthermore, these materials exhibit selectivity relative to other gases such as nitrogen, methane, and oxygen. They are useful as efficient separation agents, such sorbents and membranes. Novel free-radical and condensation polymerization approaches are used in the preparation of the poly(ionic liquids).

We claim: 
     
         1 . A solid sorbent for separation of carbon dioxide from a stream of mixed gases containing carbon dioxide, comprising a polymer of a polymerized ionic liquid monomer wherein the ionic liquid is selected from the group consisting of:
 (a) imidazolium-based ionic liquids, consisting of 1-[2-(methacryloyloxy)ethyl]-3-butyl-imidazolium tetrafluoroborate ([MABI][BF 4 ]), 1-(p-vinylbenzyl)-3-butyl-imidazolium tetrafluoroborate ([VBBI][BF 4l ]), 1-(p-vinylbenzyl)-3-methyl-imidazolium tetrafluoroborate [VBMI][BF 4 ], 1-(p-vinylbenzyl)-3-butyl-imidazolium hexafluorophosphate [VBBI][PF 6 ], 1-(p-vinylbenzyl)-3-butyl-imidazolium o-benzoic sulphimide ([VBBI][Sac]), 1-(p-vinylbenzyl)-3-butyl-imidazolium trifluoromethane sulfonamide([VBBI][BF 4 ]), and (1-butylimidazolium-3)methyl-ethylene oxide ([BIEO][BF 4 ]);   (b) ammonium-based ionic liquids, consisting of (p-vinylbenzyl)trimethyl ammonium tetrafluoroborate ([VBTMA][BF 4 ]), (p-vinylbenzyl)triethyl ammonium tetrafluoroborate ([VBTEA][BF 4 ]), (p-vinylbenzyl)tributyl ammonium tetrafluoroborate ([VBTBA][BF 4 ]), 2-(methacryloyloxy)ethyltrimethylamnonium tetrafluoroborate ([MATMA][BF 4 ]), (p-vinylbenzyl)trimethyl ammonium hexafluorophosphate ([VBTMA][PF 6 ]), (p-vinylbenzyl)trimethyl ammonium o-benzoic sulphimide ([VBTMA][Sac]), and (p-vinylbenzyl)trimethyl ammonium trifluoromethane sulfonamide ([VBTMA][Tf 2 N]);   (c) phosphonium-based ionic liquids, consisting of (p-vinylbenzyl)triethyl phosphonium tetrafluoroborate ([VBTEP][BF 4 ]), and (p-vinylbenzyl)triphenyl phosphonium tetrafluoroborate ([VBTPP][BF 4 ]);   (d) pyridinium-based ionic liquids, consisting of 1-(p-vinylbenzyl)pyridinium tetrafluoroborate ([VBP][BF 4 ]) and   (e) condensation polymerization ionic monomers, consisting of bis(2-hydroxyethyl)dimethyl ammonium tetrafluoroborate ([BHEDMA][BF 4 ]), 2,2-bis(methylimidazolium methyl)-1,3-propanediol tetrafluoroborate ([BMIMP][BF 4 ]), and 2,2-bis(butylimidazolium methyl)-1,3-propanediol tetrafluoroborate ([BBIMP][BF 4 ]).   
     
     
         2 . A solid sorbent as defined in  claim 1 , further comprising an inorganic moiety. 
     
     
         3 . A solid sorbent as defined in  claim 1 , further comprising a co-polymer. 
     
     
         4 . A solid sorbent as defined in  claim 1 , wherein the polymerization is a polymerization method selected from the group consisting of radical polymerization and condensation polymerization.