Promoted iridium complexes as catalysts in hydroformylation of 1-hexene

Iridium complexes Ir4(CO)12, IrCl3, and [IrCl(CO)3]n show activity toward hydroformylation of 1-hexene in the presence of inorganic salts as promoters. Use of promoters such as LiCl, Li2CO3, KCl, CaCl2, and LiBr enhanced the catalytic activity and aldehyde selectivity considerably by suppressing the competing hydrogenation processes. The activity of the iridium compounds increases in the order IrCl3<[IrCl(CO)3]n