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Chemical & Petroleum Engineering
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CPE Faculty and Staff

Bala Subramaniam

Bala Subramaniam

Dan F. Servey Distinguished Professor
Director, Center for Environmentally Beneficial Catalysis,
A National Science Foundation Engineering Research Center

B. S., Chemical Engineering, University of Madras, India
Ph.D., Chemical Engineering, University of Notre Dame

Learned Hall:
Voice:(785) 864-2903
Fax: (785) 864-4967

CEBC:
1501 Wakarusa Dr. Suite A-110, Lawrence, KS 66049
Voice : (785) 864-2903; Fax: (785) 864-6051

Cell: (785) 550-6271
Email: bsubramaniam@ku.edu
http://www.cebc.ku.edu/


Research Interests

Catalytic Reaction Engineering for Sustainable Energy and Chemicals Production; Exploiting Supercritical and Gas-Expanded Liquids in Crystallization and Benign Chemicals Processing.

Exploiting Supercritical Fluids in Heterogeneous Catalysis

Using relatively moderate changes in pressure, it is possible to "tune in" unique fluid properties (liquid-like density and gas-like transport) with near-critical media. Through complementary experimental and modeling investigations, our group has demonstrated that these unique properties are better suited (than those of either conventional gas or liquid phase media) for heterogeneous catalysis in ways such as these: enhanced desorption and transport of heavy molecules (such as coke precursors) in mesoporous catalysts alleviating pore-diffusion limitations and improving catalyst effectiveness; in situ removal of primary products enhancing their selectivity; and enhanced heat capacity ameliorating the problem of parametric sensitivity in exothermic fixed-bed catalytic reactors. Our group is currently focusing on exploiting these properties in several classes of heterogeneous catalytic reactions such as isomerizations, hydrogenations, Fischer-Tropsch synthesis, and alkylations.

PICTURE 1

Catalysis with Gas-Expanded Liquids

We are specifically exploiting CO2-expanded liquids (CXLs). CXLs are generated by mixing dense CO2 with traditional solvents to yield a new liquid phase (called the CXL phase). The CXL properties (such as transport coefficients and dielectric constant) are easily tuned by CO2 addition to accommodate contrasting solubilities simultaneously: a large amount of CO2 enhances permanent gas solubility and the organic solvent favors metal catalyst solubility. In collaboration with Professor Daryle Busch.s group in the Department of Chemistry at KU, our group has shown how the tunable properties of CXLs may be exploited to alleviate .gas starvation. and intensify the rates (from several fold to 1-2 orders of magnitude) of a variety of multiphase oxidations and hydroformylations, catalyzed by transition metal complexes. Environmental and safety advantages include substantial replacement of organic solvents with benign CO2, mild process pressures (tens of bars) and reduced flammability hazards due to the presence of dense CO2 in the vapor phase. Our group is currently focusing on fundamental investigations aimed at understanding the phase behavior including gas solubilities, transport properties and kinetics in CXLs. Our goal is to rationally develop and demonstrate economically viable CXL-based process concepts for a variety of industrially relevant oxidation and hydroformylation processes.We are also applying CXLs in a variety of biomass conversion processes funded by industry.

PICTURE 2

Nanoparticle crystallization and coating with dense phase carbon dioxide

Replacement of traditional solvents with dense carbon dioxide (because of its pressure-tunable physical/transport properties and environmentally-benign nature) is receiving increased attention in crystallization processes. Specifically, we have employed CO2 as an antisolvent to precipitate polar compounds from solution, including nanoparticles of pharmaceutical compounds (insulin, paclitaxel and biological compounds) and transition metal complexes with unique function. We have also developed a fludized-bed coating process similar to the Wurster coater using dense CO2 as the fluidizing medium as well as a drying agent. We have uniformly coated tablets, stents and other biomedical devices for controlled-release function. Fundamental investigations aimed at a better understanding of the nanostructure-function relationships are underway. Such an understanding is essential for the rational development of practical applications.


Representative Research Publications



Reactions in Supercritical Fluids (Reviews)


  • B. Subramaniam and M. A. McHugh, "Reactions in Supercritical Fluids - A Review,"Industrial and Engineering Chemistry Process Design and Development, 25, 1-12 (1986)

  • S. Saim and B. Subramaniam, "Chemical Reaction Equilibrium at Supercritical Conditions,"Chemical Engineering Science,43,1837-41 (1988).

  • G. Musie, M. Wei, B. Subramaniam, D. H. Busch, .Catalytic Oxidations in Carbon Dioxide-Based Reaction Media, including Novel CO2-Expanded Phases." Coordination Chemistry Reviews,219-221, 789-820 (2001).

  • B. Subramaniam, C. J. Lyon and V. Arunajatesan, .Environmentally-Benign Multiphase Catalysis,"Applied Catalysis B: Environmental,37(4),279-292 (2002).

  • P.G. Jessop and B. Subramaniam, Gas-Expanded Liquids, Chemical Reviews, 107 (6),2666-2694 (2007).


Stabilizing the Activity of Porous Isomerization Catalysts with Supercritical Reaction Media

  • S. Saim and B. Subramaniam, "Isomerization of 1-hexene on a Pt/g-Al2O3Catalyst at Subcritical and Supercritical Conditions: Temperature and Pressure Effects on Catalyst Activity," Journal of Supercritical Fluids, 3, 214-21 (1990).

  • S. Saim and B. Subramaniam, "Isomerization of 1-hexene on a Pt/g-Al2O3 Catalyst: Reaction Mixture Density and Temperature Effects on Catalyst Effectiveness Factor, Coke Laydown and Catalyst Micromeritics",Journal of Catalysis, 131, 445-56 (1991).

  • S. Baptist-Nguyen and B. Subramaniam, "Coking and Activity of Porous Catalysts in Supercritical Reaction Media", AIChE Journal, 38 , 1027-37 (1992).

  • B. Subramaniam and B. J. McCoy, "Catalyst Activity Maintenance or Decay: A Model for Formation and Desorption of Coke", Industrial and Engineering Chemistry Research, 33, 504-508 (1994).

  • B. J. McCoy and B. Subramaniam, "Continuous-Mixture Kinetics of Coke Formation from Olefinic Oligomers", AIChE J., 41, 317-323 (1995).

  • D. M. Ginosar and B. Subramaniam, "Olefinic Oligomer and Cosolvent Effects on the Coking and Activity of a Reforming Catalyst in Supercritical Reaction Mixtures", Journal of Catalysis, 152, 31-41 (1995).

  • M. C. Clark and B. Subramaniam, "1-Hexene Isomerization on a Pt/g-Al2O3 Catalyst: The Dramatic Effects of Feed Peroxides on Catalyst Activity", Chemical Engineering Science, 51, 2369-2377 (1996).

  • M. C. Clark and B. Subramaniam, Intrinsic Kinetics of Pt/g-Al2O3 Catalyzed 1-Hexene Isomerization at Supercritical Conditions, AIChE Journal, 45, 1559-65 (1999).

  • B. Subramaniam, Enhancing the Stability of Porous Catalysts with Supercritical Reaction Media, Applied Catalysis A: General, 212/1-2, 199-213 (2001).

  • V. Arunajatesan, K. A. Wilson and B. Subramaniam, Pressure-tuning the Effective Diffusivity of Near-critical Reaction Mixtures in Mesoporous Catalysts, Industrial and Engineering Chemistry Research, 42, 2639-2643 (2003).


Hydrogenations, Syngas Reactions in Near-critical Reaction Media

  • W. K. Snavely and B. Subramaniam, "On-line Gas Chromatography of Fischer-Tropsch Products Formed in a Supercritical Reaction Medium", Industrial and Engineering Chemistry Research, 36, 4413-4420 (1997).

  • D. J. Bochniak and B. Subramaniam, "Fischer-Tropsch Synthesis in Near-Critical n-Hexane: Pressure-Tuning Effects",AIChE Journal, 44, 1889-96 (1998).

  • V. Arunajatesan, B. Subramaniam, K. W. Hutchenson and F. E. Herkes, "Fixed-Bed Hydrogenation of Organic Compounds in Supercritical Carbon Dioxide", Chemical Engineering Science, 56/4, 1363-1369 (2001).

  • V. Arunajatesan, B. Subramaniam, K. W. Hutchenson and F. E. Herkes, "Continuous Heterogeneous Catalytic Hydrogenation of Organic Compounds in Supercritical CO2," Catalysis of Organic Reactions, Marcel Dekker, New York, Vol. 89, 461-475 (2003).

  • H. Jin and B. Subramaniam, "Exothermic Reactions in Supercritical Reaction media: Effects of Pressure-tunable Heat Capacity on Adiabatic Temperature Rise and Parametric Sensitivity", Chemical Engineering Science, 58, 1897-1901 (2003).

  • V. Arunajatesan, B. Subramaniam, K. W. Hutchenson and F. E. Herkes, "In situ FTIR Investigations of Reverse Water Gas Shift Reaction Activity at Supercritical Conditions," Chemical Engineering Science, 62 , 5062-5069 (2007).

Solid Acid Catalysis in Near-critical Reaction Media

  • M. C. Clark and B. Subramaniam, "Enhanced Alkylation Production Activity During Fixed-Bed Supercritical 1-Butene/Isobutane Alkylation on Solid Acid Catalysts with Carbon Dioxide as Diluent", Ind. Eng. Chem. Res., 37, 1243-50 (1998).

  • B. Subramaniam, V. Arunajatesan and C. Lyon, "Coking of Solid Acid Catalysts and Strategies for Maintaining Their Activity", in B. Delmon and G. F. Froment (Eds.), Catalyst Deactivation 1999, Stud. Surf. Sci. Catal., 126, Elsevier, Amsterdam pgs. 63-70 (1999).

  • C. J. Lyon, B. Subramaniam and C. J. Pereira, "Enhanced Isooctane Yields for 1-Butene/Isobutane Alkylation on SiO2-supported Nafion® in Supercritical Carbon Dioxide," in J. J. Spivey, G. W. Roberts and B. H. Davis (Eds.), Catalyst Deactivation 2001. Studies in Surface Science and Catalysis, 139, 221-228 (2001).

  • C. J. Lyon, V.S.R. Sarsani and B. Subramaniam, "1-Butene+Isobutane Reactions on Solid Acid Catalysts in Dense CO2-based Reaction Media: Experiments and Modeling", Industrial and Engineering Chemistry Research, 43 , 4809-4814 (2004).

  • V. S. R. Sarsani, Y. Wang and B. Subramaniam, "Toward Stable Solid Acid Catalysts for 1-Butene+Isobutane Alkylation: Investigations of Heteropolyacids in Dense CO2 Media," Industrial and Engineering Chemistry Research, 44 (16), 6491 . 6495 (2005).

  • V. S. R. Sarsani, C. J. Lyon, K. W. Hutchenson, M. A. Harmer and B. Subramaniam, "Continuous Acylation of Anisole by Acetic Anhydride in Mesoporous Solid Acid Catalysts: Reaction Media Effects on Catalyst Deactivation", Journal of Catalysis, 245, 184-190 (2007).


Catalysis in CO2-expanded Solvents

  • G. Musie, M. Wei, B. Subramaniam and D. H. Busch, "Autooxidation of Substituted Phenols Catalyzed by Cobalt Schiff base Complexes in Supercritical Carbon Dioxide", Inorganic Chemistry, 40(14), 3336-3441 (2001).

  • M. Wei, G. T. Musie, D. H. Busch and B. Subramaniam, "CO2-expanded Solvents: Unique and Versatile Media for Performing Homogeneous Catalytic Oxidations", J. American Chemical Society, 124(11), 2513-2517 (2002).

  • B. Rajagopalan, M. Wei, G. T. Musie, B. Subramaniam and D. H. Busch, "Homogeneous Catalytic Epoxidation of Organic Substrates in CO2-Expanded Solvents in the Presence of Water Soluble Oxidants and Catalysts", Industrial and Engineering Chemistry Research, 42, 6505-6510 (2003).

  • B. Kerler, R.E. Robinson, A.S. Borovik and B. Subramaniam, "Application of CO2-Expanded Solvents in Heterogeneous Catalysis: A Case Study", Applied Catalysis B: Environmental, 49(2), 91-98 (2004).

  • M. Wei, G. T. Musie, D. H. Busch and B. Subramaniam, "Autoxidation of 2,6-Di-tertbutylphenol with Cobalt Schiff Base Catalysts by Oxygen in CO2-expanded Liquids", Green Chemistry, 6(8) 387-393 (2004).

  • H. Jin and B. Subramaniam, "Catalytic Hydroformylation of 1-Octene in CO2-expanded Solvent Media", Chemical Engineering Science, 59, 4887-4893 (2004).

  • 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).

  • Y. Houndonougbo, H. Jin, B. Rajagopalan, K. Kuczera, B. Subramaniam, and B. B. Laird, "Phase Equilibria in Carbon Dioxide Expanded Solvents: Experiment and Molecular Simulations", J. Physical Chemistry B., 110(26), 13195-13202 (2006).

  • S. Sharma, B. Kerler, B. Subramaniam and A.S. Borovik, "Immobilized Metal Complexes in Porous Hosts: Catalytic Oxidation of Substituted Phenols in CO2Media", Green Chemistry, 8, 972-977 (2006).

  • Hyun-Jin Lee, Tie-Pan Shi, Bala Subramaniam, Daryle H. Busch, "Selective Oxidation of Propylene to Propylene Oxide in CO2 Expanded Liquid System", in S. R. Schmidt (Ed.), Catalysis of Organic Reactions, Chemical Industries Series, Vol. 115, CRC Press, Taylor & Francis Group LLC, Boca Raton, FL.,pgs. 447-451 (2006).

  • D. Guha, H. Jin, M.P. Dudukovic, P.A. Ramachandran and B. Subramaniam, "Mass transfer effects during homogeneous 1-Octene hydroformylation in CO2-expanded solvent: Modeling and Experiments," Chemical Engineering Science, 62, 4967-4975 (2007).

  • H-J Lee, T-P Shi, D. H Busch and B. Subramaniam, "A Greener, Pressure Intensified Propylene Epoxidation Process with Facile Product Separation," Chemical Engineering Science, 62, 7282-7289 (2007).

  • 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).

  • X. Zuo, B. Subramaniam and D. H. Busch, "Liquid phase oxidation of toluene and p-toluic acid under mild conditions: synergistic effects of cobalt, zirconium, ketones and carbon dioxide," Industrial and Engineering Chemistry Research, 47, 546-552 (2008).

  • B. Rajagopalan, B. Subramaniam and D.H.Busch, "The catalytic efficacy of Co(salen)(AL) in O2 oxidation reactions in CO2-expanded solvent media: axial ligand dependence and substrate selectivity," Catalysis Letters.


Crystallization and Coating with Dense Carbon Dioxide

    B. Subramaniam, R. A. Rajewski and W. K. Snavely, "Pharmaceutical Processing with Supercritical Carbon Dioxide", Journal of Pharmaceutical Sciences, 86, 885-890 (1997).

  • W. K. Snavely, B. Subramaniam, R. A. Rajewski, M. R. DeFelippis, "Micronization of Insulin from Halogenated Alcohol Solution Using Supercritical Carbon Dioxide as an Antisolvent", Journal of Pharmaceutical Sciences, 91(9), 2026-2039 (2002).

  • C. Lin, G. Muhrer, M. Mazzotti and B. Subramaniam, "Vapor-Liquid Mass Transfer During Gas Antisolvent Recrystallization: Modeling and Experiments", Industrial and Engineering Chemistry Research, 42, 2171-2182 (2003).

  • F. Fusaro, M. Hähen, and M. Mazzotti, G. Muhrer and B. Subramaniamm, "Dense Gas Antisolvent Precipitation: A Comparative Investigation of the GAS and PCA Techniques", Industrial and Engineering Chemistry Research, 44, 1502-1509 (2005).

  • C. A. Johnson, S. Sharma, B. Subramaniam and A. S. Borovik, "Nanoparticulate Metal Complexes Prepared With Compressed Carbon Dioxide: Correlation of Particle Morphology with Precursor Structure", Journal of the American Chemical Society, 127 (27) , 9698-9699 (2005).

  • F. Niu and B. Subramaniam, "Particle Fluidization with Compressed CO2: Experiments and Theory," Industrial & Engineering Chemistry Research, 46, 3153-3156 (2007).