Promoting effect of water on 1-hexene hydroformylation catalyzed by aminophosphine–rhodium complexes

Abstract

A series of (o-alkylaminophenyl)diphenylphosphine ligands (P-N ligands) containing different alkyl carbon numbers or amino groups have been synthesized and characterized by IR and NMR ( 1 H, 13 C, 31 P). The rhodium complexes ligated with P-N ligands in the hydroformylation of 1-hexene showed a considerable enhancement with the addition of water. NMR characterization studies suggested that the addition of water would engage in hydrogen bonding to the nitrogen atom of the coordinated P-N ligand, inhibiting the internal Rh-N interaction and generating more of the active unsaturated Rh-species that could react with 1-hexene to start the hydroformylation.