Patent ID: 8734744

Claim:
A process for removing carbon dioxide from a gaseous stream comprising contacting the gaseous stream with a carbon dioxide absorbent comprising a mixture of an ionic liquid and water in a molar ratio of from 10:1 to 1:10, wherein the ionic liquid has the formula: [Cat + ][X − ] wherein: [Cat + ] represents one or more cationic species selected from tetrasubstituted phosphonium cations, tetrasubstituted ammonium cations, trisubstituted sulfonium cations, guanidinium cations and quinolinium cations; and [X − ] represents one or more anionic species selected from conjugate bases of acids having a pKa of at least 3.6, where the one or more anionic species includes at least one of phosphate dianions, phosponate dianions, or dicarboxylate dianions, with the proviso that [X − ] is not formate, acetate, trifluoroacetate, hydroxyacetate, propanoate, pentafluoro-propanoate, lactate, butanoate, isobutanoate, pivalate, pyruvate, thiolactate, oxalate, tartrate, malonate, succinate, adipate or benzoate.