(678b) Combining Homogeneous Reactions with Heterogeneous Separations for the Hydroformylation of Styrene Using Tunable Solvents

Fadhel, A. Z. - Presenter, Georgia Institute of Technology
Ford, J. W. - Presenter, University of Kansas
Wu, A. - Presenter, Georgia Institute of Technology
Mestre, V. L. - Presenter, Georgia Institute of Technology
Pollet, P. - Presenter, Georgia Institute of Technology, Specialty Separations Center
Liotta, C. L. - Presenter, Georgia Institute of Technology
Eckert, C. - Presenter, Georgia Institute of Technology

Organic Aqueous Tunable Solvents combine the benefits of homogeneous and heterogeneous catalysis while overcoming the limitations of both. We are using the hydroformylation of hydrophobic p-methylstyrene as a model chiral reaction, which mimics the active pharmaceutical ingredient in ibuprofen production. The homogeneous hydroformylation reaction is carried out in organic-water mixtures using Rh/TPPMS catalytic complex under 3 MPa of syngas. Reaction rates are improved by an order of magnitude and the yield is increased by 20% when compared to reported heterogeneously catalyzed reactions. After the reaction, moderate pressures of carbon dioxide (around 3 MPa) are used to induce a phase split, as the gas is almost insoluble in water but completely miscible with most organic solvents. The hydrophobic product partitions into the organic-rich phase, which is decanted and then depressurized to yield a facile separation of >99% recovery. The aqueous-rich phase, which contains 99.9% of the hydrophilic catalyst, is recycled for the next reaction cycle. We show five recycles of the catalyst without significant loss of activity.