A reversible zwitterionic SO2-binding organic liquid

Abstract

N,N-Dibutylundecanolamine is a liquid that chemically binds SO₂ to form a viscous zwitterionic liquid that contains 35% by wt. SO₂ at standard temperature and pressure. SO₂ is chemically bound to the alcohol component as an alkylsulfite, which is then stabilized by the amine. The zwitterionic liquid can be reverted to its non-ionic form and recycled by thermally stripping the SO₂ under vacuum at temperatures near 70 °C. N,N-Dibutylundecanolamine is a potential flue gas desulfurizing solvent because it is chemically selective to bind SO₂ but not basic enough to chemically bind CO₂.