Novel Thermoregulated Phosphine Ligand And It's Rhodium Complex Catalyzed Hydroformylation Of 1-Octene In Liquid/liquid Biphasic System

The research on water-soluble phosphines modified catalysts and aqueous/organic biphasic catalysis system provides a promising avenue for the recycling of noble metal catalysts, and it has become a hot topic in homogeneous catalysis. In this paper, based on the concept of Thermoregulated Phase-traster Catalysis (TRPTC) , a novel nonionic phosphine ligand with thermoregulation function has been designed and synthesized, of which the structure is shown below,In order to avoid the oxidation effect of oxirane while preparing nonionic phosphine through ethoxylation reaction, and the difficulty in controlling the length of polyether chain, a new synthetic method was developed. Using MeOPEG₇50(CH₃(OCH₂CH₂)_nOH, Mw =750) as raw material, ligand( â… ) is prepared via the reactionof CH₃(OCH₂CH₂)_nOSO₂CH₃ (Mw =828) and LiPPh₂. The ligand obtained has also beenverified to have function of temperature-dependent water solubility—cloud point. Thestructure of this ligand and the chelating status have been characterized through NMR technique, and the results are similar to those reported for other ligands and complexes of this type.In this study, rhodium complex formed in situ by Rh(CO)₂(acac) with ligand( â… ) has been used in aqueous/organic biphasic hydroformylation of 1-octene. The effect of temperature, pressure of synthesis gas, reaction time, and the ratio of P/Rh etc. has been tested and discussed in detail. The preferable reaction condition got is, S/Rh=1000, P/Rh=13, 90℃, 5.0MPa(H₂/CO=1:1), t=5h. Under this condition, the conversion of 1-octene and yield of nonanal are 98.4% and 97.3% respectively, n/i=0.81, and TOF=195h^-1 After 5 times of the catalyst recycle, the conversion of 1-octene and yield of nonanal are still above 90%. The Rh loss after the first run of reaction has been detected by ICP-MS to be 8.2% of the total Rh used, and the loss decreases gradually in the following runs of reactions, after the sixth run, it decreased to 1.3%.The Ligand( â…  )/Rh has also been applied in PEG biphasic system to inspect the catalytic capability, as well as the separation and recycle of the catalyst. In this system, thecatalytic capability, as well as the separation and recycle of the catalyst. In this system, the catalyst can be repeatedly used 8 times with a high catalytic activity. The conversion of 1-octene and yield of nonanal are both above 95%. The Rh loss in the upper product phase is detected by ICP-MS to be 1.56%. This section of experiment extended the application scope of ligand( â… ).