Water Soluble Phosphines, Their Transitional Metal Complexes, and Catalysts

In recent years two-phase catalysis has been established as a new field of catalyzed processes and has achieved industrial-scale importance in olefin hydroformylation. Two-phase reactions have a number of advantages, for example, ease of separation of catalyst and product, catalysts can be tailored to the particular problem, use of special properties and effects of water as a solvent, and low environmental impact. For higher olefins (* C6), the reaction suffers low activity due to low water solubility of higher olefins.

Tricesium analog of TPPTS, m,m,m-trisulfonated triphenylphosphine, was synthesized and fully characterized. Two-phase olefin hydroformylation with Rh(acac)(CO)2 was investigated. The results indicated that both activity and selectivity (linear to branch aldehyde ratio) are similar to Rh/TPPTS system. The salt effect showed that increase the solution ionic strength will increase the selectivity and decrease the activity in the olefin hydroformylation with TPPTS.

A new surface active phosphine, trisulfonated tris-m-(3henylpropyl)phenylphosphine, was synthesized and fully characterized. The results of biphasic olefin hydroformylation were consistent with aggregation of the ligand. The two phase 1-octene hydroformylation results showed that with only 3 methylene groups, there is no difference between the para and meta position of C3 group.

A new chelating diphosphine, tetrasulfonated 2,2'-bis{di[p-(3 phenylpropyl)phenyl]phosphinomethyl}-1,1'-biphenyl,was prepared and fully characterized. Its application in two-phase hydroformylation of olefin showed enhanced activity and selectivity compared to the non-chelated phosphine analog.

Finally, homogeneous asymmetric hydrogenation was carried out in the presence of a chiral surfactant in an attempt to affect asymmetric induction. The catalytic results showed that at a surfactant/Rh ratio of 25, the asymmetric hydrogenation of AACA-Me (a-Acetamidocinnamic Acid Methyl Ester) in methanol has no effect on asymmetric induction with the introduction of this chiral surfactant.