Sour gases (e.g. CO2 and H2S) have to be removed from gaseous streams in many industrial processes. The task is often achieved by an absorption of the sour gases in aqueous solutions of amines (e.g. MEA. MDEA, piperazine) followed by a recovering (desorption) process. Both processes (absorption and desorption) are governed by chemical reaction equilibria and chemical reaction kinetics. Therefore, the design of the absorption/desorption processes requires a thermodynamic framework for the solubility of sour gases in aqueous solutions of single amines as well as of amine blends. Such phase equilibria (as well as related phenomena) have been in the focus of the research of the author's group for more than a decade. Recent results – from theoretical work as well as from modeling – will be presented and discussed.