In situ synthesis of Rh@NaX catalyst for 1-hexene hydroformylation

The hydroformylation reaction is very important in industry. However, the leaching of the noble metal Rhodium (Rh) and the separation of homogeneous catalyst have always been difficult problems to solve. And even heterogeneous Rh-base catalyst was developed to solve the separation problem, the serious Rh losing is still hard to avoid. In this work, heterogeneous encapsulated Rh@NaX was prepared by using one-step synthesis method and used as catalyst without reduction in 1-hexene hydroformylation reaction. Rh@NaX catalyst exhibited outstanding catalytic performance. When directly complexed with ligand triphenylphosphine (PPh), it achieved high heptanal yield of 97.53 %, high n/i ratio of 2.59 and high TOF of 6588 h. Interestingly, encapsulated catalyst exhibited higher recycling stability and much lower Rh leaching compared to impregnated catalyst. In addition, in situ XPS and DRIFT analyses were conducted to elucidate the reduction process of Rh and the reaction pathway.