(315b) Highly Active and Recyclable Hydroformylation Catalysis Using Soluble Polymer Supports In CO2-Expanded Liquids (CXLs)
AIChE Annual Meeting
2008
2008 Annual Meeting
Engineering Sciences and Fundamentals
Reactions at High-Pressures
Tuesday, November 18, 2008 - 12:55pm to 1:20pm
A process concept that
exploits CXLs to intensify hydroformylation reactions was recently
demonstrated.[1] When dense CO2 is used to
partially replace the excess substrate (1-octene) to create a CO2-expanded
liquid (CXL) phase, the 1-octene hydroformylation turnover frequency (~300 h-1)
and the selectivity towards the linear aldehyde (~90%) are significantly
enhanced relative to the reaction in neat media. Further, these enhancements
occur at mild pressures (~40 bar) and temperatures (60°C). Preliminary
economic analysis indicates that near-quantitative (>99.8%) recovery of the
Rh-based catalysts is essential for commercial viability.[2]
Toward this end, soluble polymer supported bidentate phosphite ligands for
hydroformylation of higher (> C4) alkenes have been developed and
evaluated. The efficient
separation and recycle of homogeneous rhodium catalyst complexes from reaction
mixtures is attempted by using membrane filtration technology in a
high-pressure filtration cell equipped with cross-linked asymmetric polyimide nano-
and ultra- filtration membranes. Experiments with the catalyst complex
dissolved in pure toluene revealed a Rh loss in the permeate of less than 1%
while no P was detectable in the permeate. Similar measurements at actual
hydroformylation conditions are ongoing. The effects of dissolved CO2
(in the CXL media) on the solution viscosity and the permeate flux will be
discussed. In addition, results on the recyclability and durability of
polymer supported rhodium catalyzed 1-octene hydroformylation in CXLs will be
presented.
H. Jin, A. Ghosh, J. A. Tunge and B.
Subramaniam, "Intensification of Catalytic Olefin Hydroformylation in CO2-expanded
Media", AIChE Journal, 52(7), 2575-2591 (2006).
[2]. J. Fang, H. Jin,
T. Ruddy, K. Pennybaker, D. Fahey and B. Subramaniam, "Economic and
Environmental Impact Analyses of Catalytic Olefin Hydroformylation in CO2-Expanded
Liquid (CXL) Media," Industrial and
Engineering Chemistry Research, 46,
8687-8692 (2007).