This paper presents the new highly selective iridium-catalyzed hydroformylation of 1-octene with an Ir(cod)(acac)/PPh3/salt catalyst system. The addition of inorganic salts such as LiCl suppresses the hydrogenation of 1-octene and increases the yield of desired hydroformylation products. Even low amounts of LiCl (LiCl/Ir =2/1) significantly increase the chemoselectivity of aldehydes up to 94% with a 1-octene conversion of 90% within 7 h. This catalyst is applicable to other alkenes such as 1-p entene or 1-dodecene. The high selectivities and the remarkable activity of the optimized iridium catalyst are promising in terms of successfully implementing on an industrial scale in the future. (C) 2015 Elsevier B.V. All rights reserved.