(713a) Effect of Compressed Gas Addition On H2/CO Tunability and Hydroformylation Catalysis In Gas-Expanded Liquids (GXLs)

Previously,
we had reported on the beneficial effects of carbon dioxide expanded liquids
for hydroformylation^{1, 2}. In this talk, we present systematic
investigations of the comparative effects of compressed gases (CO₂
and light alkanes) on the relative miscibilities of
CO and H₂ in GXLs and also the corresponding effects on Rh-based
hydroformylation catalysis with monodendate (triphenylphosphine) and bidendate
ligands. It is shown that the H₂/CO ratio in the gas-expanded liquid
phase (containing substrate and dissolved catalyst complex), a key determinant
of the turnover frequency and regioselectivity, can
be easily tuned with GXLs to optimize these performance measures at relatively
mild pressures³. Continuous hydroformylation with bulky phosphite ligands is demonstrated in a GXL-based stirred
reactor equipped with nanofiltration membranes.  It is shown that the Rh
leaching from these reactors is on the order of a few tens of ppb, which easily
exceeds the economic viability criterion^{4, 5}.   
 

1.     
H.
Jin, A. Ghosh, J. A. Tunge
and B. Subramaniam, AIChE
Journal, 52(7), 2575-2591 (2006)

2.     
H.
Jin and B. Subramaniam, Chem. Eng. Sci., 59,
4887, (2004)

3.     
Z. Xie, W. Snavely, A. Scurto, and B. Subramaniam, J.
Chem. Eng. Data, 54 (5), 1633, (2009)

4.     
J.
Fang, H. Jin, T. Ruddy, K. Pennybaker, D. Fahey and
B. Subramaniam, Industrial and Engineering
Chemistry Research, 46, 8687-8692 (2007)

5.     
J.
Fang, R. Jana, J. Tunge, B. Subramaniam,
Applied Catalysis, A: General, 393(1-2), 294-301 (2011)