A regenerative process used to remove or reduce the level of hydrogen sulphide, carbon dioxide, carbonyl sulphide, and other organic sulphur compounds such as mercaptans from natural gas. It involves gas absorption with solvents in which the gas is contacted countercurrently in an absorption column with the solvent. The scrubbing process uses di-isopropanolamine dissolved in a mixture of sulfolane (C₄H₈SO₂) and water. Regenerated solvent is introduced at the top of the absorber. The solvent in which (p. 366) the sulphur compounds are absorbed is heated in a heat exchanger with the regenerated solvent and is fed back to the regenerator where it is further heated to release the dissolved gases using steam. The gas is passed to a Claus process to recover elemental sulphur. The process was developed in the 1960s.