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Professor Bala
Subramaniam
Dan F. Servey Distinguished Professor of Chemical & Petroleum Engineering
& Director
Center for Environmentally Beneficial Catalysis (CEBC)
University of Kansas
Lawrence, KS 66045
Center for Environmentally Beneficial Catalysis
Abstract
A gas-expanded liquid (GXL) phase
is formed by dissolving a compressible gas such as CO2 or
a light olefin into the traditional liquid phase (the resulting
liquid phase is termed CO2-expanded liquid or CXL when CO2
is used as the expansion gas).1 This talk will address
the various unique ways in which GXL media have been exploited by
CEBC researchers to develop greener catalytic process concepts for
O2 and H2O2-based oxidations,
hydroformylations and ozonolysis. The demonstrated advantages
include process intensification at mild conditions by increasing
dissolution of the limiting reagent (gaseous reactants such as O2
or syngas or light olefins) in the GXL reaction phase;2
the efficient utilization of feedstock and reactive gases such as O3
due to the inertness of CO2, an often used expansion
medium; enhancing inherent safety of the process by suppression of
flammable vapors; synthesis of novel nanomaterials of transition
metal complexes with unique function for reversible oxygen binding
and room-temperature nitric oxide disproportionation;3
and waste mitigation by reduced usage of organic solvents and by
suppression of side reactions that generate undesired byproducts
such as CO2.
Specific examples of novel process concepts will include propylene
oxide production with environmentally benign solvents and oxidant,
exploiting the compressibility of propylene at ambient temperatures
for process intensification;4 a novel homogeneous
ethylene oxide process virtually eliminating CO2
formation as a byproduct;5 highly selective
hydroformylation of higher olefins at mild conditions employing
soluble polymer-supported Rh catalysts that are easily retained in
solution while the product is isolated by membrane filtration;6
and a novel spray reactor concept to overcome gas-liquid transport
limitations for the inherently safe formation of terephthalic acid
from p-xylene at high yields and purity, and with potentially
reduced solvent burning.7 Quantitative economic and
environmental impact analyses have been employed to benchmark CEBC’s
novel technology concepts against conventional processes.8
Such comparative analyses not only guide research and development
but also assist CEBC’s industry partners in making business
decisions about adopting sustainable technologies.
References
1. P.G. Jessop and B. Subramaniam,
Chem. Rev.,
107,
2666 (2007).
2. (a) M. Wei et al.,
J. Am. Chem. Soc.,
124,
2513 (2002); (b) H. Jin et al.,
AIChE J.,
52,
2575 (2006); (c) Y. Houndonougbo et al.,
J. Phys. Chem. B.,
110,
13195 (2006); Z. Xie et al.,
J Chem. Eng. Data,
54,
1633 (2009).
3. (a) C. A. Johnson et al.,
J. Am. Chem. Soc.,
127,
9698 (2005); (b) J. Nguyen et al.,
Chem. Matls.,
20,
5939(2008); (c) C. A. Johnson et al.,
J. Phys. Chem. C.,
112,
12272 (2008); (c) C. Johnson et al.,
AIChE J.,
55,1040-1045
(2008).
4. H. -J Lee, T-P Shi, D. H Busch and B. Subramaniam,
Chemical Engineering Science,
62,
7282-7289 (2007).
5. H. –J. Lee et al.,
Chem. Eng. Sci. 2009
(in press). DOI: 10.1016/j.ces.2009.1002.1008
6. H. Jin et al., AIChE
Journal,
52,
2575 (2006); D. Guha, et al.
Chem. Eng. Sci.,
62,
4967
(2007);
R. Wang, et al. in
Gas-Expanded Liquids and Near-Critical Media: Green Chemistry and
Engineering, Eds.,
Hutchenson, K.W., A.M. Scurto, and B. Subramaniam , ACS Symposium
Series No. 1006, American Chemical Society: Washington, D.C. 2009,
pp. 202-217.
7. D. H. Busch, B. Subramaniam, in
Gas-Expanded Liquids and
Near-Critical Media: Green Chemistry and Engineering,
Eds., Hutchenson, K.W., A.M.
Scurto, and B. Subramaniam, ACS Symposium Series No. 1006, American
Chemical Society: Washington, D.C. 2009, pp. 145-190.
8. J. Fang et al. Ind.
Eng. Chem. Res.,46,
8687 (2007); K. Gong et al.
Ind. Eng. Chem. Res.,
47,
9072 (2008). |