Bala Subramaniam is the Dan F. Servey Distinguished Professor of Chemical Engineering at the University of Kansas (KU). Subramaniam earned a B.Tech. degree in Chemical Engineering from the University of Madras, India and his Ph. D. in Chemical Engineering from the University of Notre Dame. He has also held visiting professorships at the University of Nottingham, United Kingdom and the Institute of Process Engineering, ETH, Zürich, Switzerland.
Subramaniam’s research interests are in catalysis, reaction engineering and crystallization. His group has made seminal contributions in understanding catalysis in complex yet practically relevant environments characterized by moderate to high pressures, use of pressure-tunable reaction media such as liquid CO2 and gas-expanded liquids, and challenging reagents such as ozone. The Subramaniam group has developed novel reactors to experimentally probe the complex interplay between catalysis, phase behavior and transport phenomena in such systems. Such knowledge has led to the development of a number of resource-efficient technologies with reduced environmental footprint. He has 180+ journal publications, 29 issued patents and edited 2 books. Subramaniam is co-founder and founding Director of the Center for Environmentally Beneficial Catalysis (CEBC), a unique University/Industry consortium that is developing and providing licensing opportunities for novel sustainable technologies related to fuels and chemicals. He also co-founded CritiTech, a pharmaceutical company based in Lawrence, KS.
Subramaniam is executive editor of ACS Sustainable Chemistry and Engineering journal and chair of the 2018 Gordon Research Conference on Green Chemistry. He has served as the President of the International Symposia in Chemical Reaction Engineering (ISCRE, Inc.) and on the Board of Directors of the Organic Chemical Reactions Society (ORCS). His honors include ASEE’s Dow Outstanding Young Faculty Award, Indian Institute of Chemical Engineers’ Chemcon Lectureship Award, and KU’s Higuchi Research Achievement Award. Subramaniam is a Fellow of the AIChE, the ACS Industrial & Engineering Chemistry Division, and the National Academy of Inventors.
Catalytic Reaction Engineering for Sustainable Fuels and Chemicals Production; Exploiting Supercritical and Gas-Expanded Liquids in Crystallization and Benign Chemicals Processing.
Exploiting Supercritical Fluids in Heterogeneous Catalysis
The foremost guiding principles underlying the sustainable development and growth of the global chemical enterprise are process intensification at mild conditions, minimization of waste and of adverse environmental footprints, and enhancement of inherent process safety. During the last two decades, we have exploited near-critical media to develop novel catalytic process concepts that admit these attributes. Central to these innovations is the recognition that with 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. These concepts have numerous novel applications in heterogeneous catalysis such as: (a) facile desorption and transport of heavy molecules (including coke precursors) in mesoporous catalysts, alleviating pore-diffusion limitations and improving catalyst effectiveness; (b) enhancing product selectivity; and (c) exploiting the enhanced heat capacity of near-critical media to ameliorate parametric sensitivity in exothermic reactions. We have demonstrated these features in several classes of reactions such as isomerizations, hydrogenations, Fischer-Trøpsch synthesis and alkylations.
Sustainable Catalysis with Gas-Expanded Liquids
During the past decade, we have exploited the pressure-tunable properties of gas-expanded liquids (GXLs) in a variety of catalytic systems. At ambient temperatures, gases such as carbon dioxide (CO2) and light hydrocarbons (such as propylene and ethylene) are close to their critical temperatures (i.e., between 0.7 -1.3 Tc). When these gases are mildly compressed (to tens of bars) at ambient temperatures, they dissolve in most conventional solvents and volumetrically expand them. The increased free volume of the GXL phases accommodates permanent gases such as O2, H2 and CO in unusually high concentrations. For example, O2 and light olefin concentrations are increased by one or two orders of magnitude in GXLs at ambient conditions, relative to conventional solvents, with similar increases in reaction rates. Remarkably, higher H2/CO ratios can be achieved in CO2-expanded liquids relative to conventional liquid phases, which not only averts CO inhibition but also dramatically shifts the product selectivity to the desired linear aldehyde product during olefin hydroformylation.
We have demonstrated several novel GXL-based catalytic reaction engineering concepts. These include (a) highly selective hydroformylation of higher olefins at mild conditions (~40 bars, 60°C) employing soluble polymer-supported homogeneous catalysts which are easily retained in solution by membrane filtration; (b) inherently safe liquid phase ethylene epoxidation process that totally eliminates CO2 formation as a byproduct; (c) a spray reactor concept for the single step formation of high purity terephthalic acid with reduced solvent burning (i.e., reduced carbon footprint). For each of these applications, we have performed cradle-to-grave LCA to quantify the extent of reduction of GHG emissions and toxicity in the alternative processes. Such detailed sustainability analyses of GXL-based process concepts point toward broader applications of GXLs extending them to biomass-derived substrates.
Engineering Micronization and Coating Applications with Dense Phase Carbon Dioxide
Particle micronization with supercritical carbon dioxide (scCO2) allows for reproducible crystal formation with the potential for increased surface area (hence enhanced dissolution rates) and concomitant sterlization. Coating with dense phase CO2 allows the use of traditional organic soluble coatings with complete solvent recovery and virtually no atmospheric emissions.
For particle micronization, ultrasonic energy is used to form droplets of drug solution. The scCO2 selectively extracts the solvent precipitating the drug. The effluent from the precipitation chamber is led to a second high-pressure vessel where the particles are separated from the solvent-laden scCO2. Collection vessel switching allows for continuous particle production. Demonstrated advantages include the continuous production of virtually solvent-free drug particles in a narrow size range and ease of process scalability to a commercial-scale crystallizer.
For coating applications, dense phase CO2 is used to fluidize the substrates and also remove solvent from the coating solution (i.e., as an antisolvent) in a Wurster-type coater, thereby precipitating the coating. The system was used to coat a variety of substrates including tablets and stents for controlled release application as well as precision coating of substrates with very small quantities of high potency drugs for ease of handling and accurate dosing.
Specific products developed using these processes include taxol nanoparticles (Nanotax®), insulin nanoaggregates, polymer-coated stents, lyophilized drugs, etc.). These patented technologies have been licensed to a startup company (CritiTech, Inc., http://www.crititech.com/) that is in the process of commercializing them and the products thereof. The Nanotax® anticancer drug produced using this technology is now undergoing clinical trials in the U.S.
In recent years, we have also exploited GXLs to synthesize nanomaterials of transition metal complexes with unique function. For example, Co(salen) based nanoparticles provide stoichiometric O2 storage capacity and room temperature NO disproportionation activity. This discovery has led to the possibility of bottom-up design of metal nanoparticles with targeted functional property.
Metal-exchanged Mesoporous Silicates with Tunable Acidity
Emerging feedstocks from biomass and natural gas liquids (NGLs) pose unique opportunities for catalyst development for resource-efficient (i.e., conserving feedstock and energy) conversion of these feedstocks to petrochemical intermediates. For example, versatile catalysts that are composed of earth-abundant materials with tunable properties (such as pore size and acidity) are desirable to process feedstock molecules ranging from NGLs (C1-C5) to bulky biomass-based molecules (C18+). In this context, very recently, we have synthesized several novel metal-exchanged mesoporous silicates that are highly tunable with respect to acidity and may be synthesized to accommodate a wide range of pore sizes (2-9 nm). We have successfully incorporated metals such as Ce, Zr, W and Nb, into silicates such as MCM-48, KIT-5, KIT-6, SBA-16 and TUD-1.
The metal-exchanged silicates show remarkable activity for a variety of chemical transformations, providing in many cases the best activity and selectivity reported to date. For example, highly selective isopropanol and ethanol dehydration activities (used as probe reactions) have been observed with Zr-KIT-6 catalysts with moderate activation energy. Remarkable ethylene epoxidation activity has been observed on Nb-KIT-5, KIT-6 and TUD-1 catalysts at mild conditions without CO2 formation as byproduct. These catalysts have been demonstrated to provide unprecedented activity for Friedel-Crafts alkylation as well. Other potential applications of these acidic catalysts include Meerwein–Ponndorf–Verley (MPV) reduction, Prins cyclizations, and olefin metatheses (such as the dimerization of C2 olefins followed by metatheses to produce C3 olefins). Clearly, these new classes of catalysts, composed of inexpensive earth-abundant metals, show much potential for development and practical implementation, especially in the fledgling biomass and NGLs-based refineries. We are developing optimized formulations of metal-incorporated mesoporous silicates (i.e., with optimal pore sizes and tuned acidities) to be used for catalytic processing of bulky biomass substrates, such as dehydration of glycerol and epoxidation of long-chain fatty acid methyl esters to produce value-added products.
- BS, Chemical Engineering, University of Madras, India
- PhD, Chemical Engineering, University of Notre Dame
Creative solutions to engineering problems require a sound complement of fundamental knowledge, intuition, imagination and critical thinking. I believe that a teacher has a vital role and challenge in fostering these attributes in students. My teaching methods are aimed at achieving this goal. In the theory courses, I show how engineering equations are essentially 'math-based languages' or models that aid our understanding of physical and chemical processes. I constantly encourage students to assess if the process behavior predicted by the model makes intuitive sense. Given that commercial software is invariably used for equation-solving and design purposes, it is especially essential to develop such an understanding and intuitive feel for interpreting results from computer simulations. I provide examples of how theories and equations have been used to develop engineering solutions in everyday life. In addition to traditional homework assignments that emphasize fundamentals and solution procedures, I assign two to three open-ended projects that are comprehensive in nature. These projects address industrially important problems and require students to integrate fundamental knowledge, intuition and imagination in critically analyzing and designing sustainable engineering processes that are resource-efficient (i.e., conserve feedstock and energy). I emphasize how resource-efficient technologies not only make good business sense but also are inherently green.
I believe that the laboratory courses provide a vital forum for not only reinforcing theoretical concepts but also developing essential experimental, data analysis, troubleshooting, team work and communication skills. The analysis/interpretation of experimental data form the basis for the preparation of various types of written reports (journal-type, memos, etc.) and oral presentations. Prior to each laboratory session, I require student teams to make concise presentations about their planned work and to rigorously defend their work plan. Besides providing training in oral and written communication skills, this process also helps students to solidify their understanding of theory.
Clear statement of course goals and expectations, effective lectures and notes, challenging yet fair assignments and tests, and accessibility to students are all essential to a positive learning experience -- one that motivates students' desire to learn and to excel. My teaching methods continue to evolve as I have learned more about teaching tips and techniques from student/peer feedback and from periodicals such as the Teaching Professor and Chemical Engineering Education, especially those that use modern technology-based classrooms to deliver instruction in novel ways.
My major teaching interests are in the areas of chemical engineering kinetics, reactor design, industrial development of sustainable catalytic processes, transport phenomena, mathematical methods in chemical engineering, and supercritical fluid technology.
- Chemical engineering kinetics and reactor design
- Mass transfer
- Mathematical methods in chemical engineering
- Industrial development of sustainable catalytic processes
- Chemical engineering unit operations laboratories
- Undergraduate and graduate course
The modern day ‘petrochemical’ refinery relies primarily on fossil-based feedstock (such as petroleum, natural gas and coal) to produce the essential chemical intermediates for everyday products (medicines, packaging materials, synthetic fibers, detergents, coolants, etc.). To meet the sharply increasing global demand for such products, alternate feedstocks such as plant-based biomass and shale gas are also being considered to make these chemical intermediates. These alternate sources, however, require the development of new technologies. Our research is focused on developing resource-efficient technologies, which conserve feedstock and energy, for both conventional and emerging sources. We address this challenge by discovering catalysts that selectively transform the feedstock to desired products minimizing waste, using tunable solvents that provide both reaction benefits and environmental benefits such as reduced toxicity and carbon footprints, and developing novel reactors that are energy-efficient in converting raw materials to products. Working in collaboration with several industry partners of the Center for Environmentally Beneficial Catalysis (CEBC), we have demonstrated such novel alternative technologies for many important chemical intermediates. In addition to economic assessment, we also perform cradle-to-grave life cycle analysis (LCA) of the new technologies to assess environmental performance and sustainability. One such technology for making ethylene oxide (a plastic precursor) received a prestigious award from the American Chemical Society. Archer Daniels Midland (ADM), a global leader in agricultural processing, recently opened research operations in Lawrence, KS to work closely with University of Kansas CEBC researchers to develop technologies that convert ADM’s myriad plant-based feedstocks to value-added products. Such collaborations have been augmented by funding from federal agencies (US Department of Agriculture, National Science Foundation and Environmental Protection Agency) to the tune of nearly $17 million since 2011. The development of such technologies has significant economic implications for the State of Kansas given its unique mix of natural resources that include not only plant-based biomass but also natural gas, crude oil and wind energy potential. A manufacturing sector built around these resources can be thriving and make Kansas among the global leaders in the manufacture and export of “renewable chemicals”.
More details of the research program and a list of selected publications may be found in the "Research Interests" section of this website.
- Catalysis and reaction engineering for resource-efficient chemicals/fuels production from conventional and biomass feedstocks
- Exploiting supercritical and gas-expanded liquids in crystallization and benign chemicals/fuels processing
I have been active in service activities at both the University of Kansas and the professional societies [American Institute of Chemical Engineers (AIChE) and the American Chemical Society (ACS)]. I especially like roles where I am able to contribute to transformational changes that have long-term beneficial impacts on the institutions I serve.
I have served as graduate advisor of the chemical and petroleum engineering (C&PE) department to streamline graduate advising, curricular and graduate recruitment activities. Later on, I served as department chair when the C&PE faculty implemented a five-year strategic plan with positive outcomes including the creation of a NSF engineering research center [the Center for Environmentally Beneficial Catalysis, CEBC], increased external research funding, the addition of five new faculty lines for interdisciplinary initiatives in the areas of catalysis and bioengineering, and the successful mentoring and nominations of several faculty for teaching and research awards.
As CEBC director, a unique industry partnership program was implemented. In partnership with member companies (that have included ADM, BASF Catalysts, BP, ConocoPhillips, Chevron Phillips, DuPont, Eastman Chemicals, Evonik, ExxonMobil, Grace, Invista, Procter&Gamble, Novozymes, Reliance Industries, SABIC, SI Group, and UOP), the CEBC is developing and providing licensing opportunities for novel sustainable technologies related to fuels and chemicals.
Since its inception, the CEBC has launched several multidisciplinary research initiatives dealing with sustainable catalysis for producing fuels and chemicals with funding from federal, state and industry sources. The total funding from these sources exceeds $50 million since 2003. These successes have resulted in the addition of several faculty members in the chemistry and C&PE departments. I chaired the recruitment of several of the current C&PE faculty members in the areas of catalysis, reactor engineering and materials science. I serve as mentor to several of the young faculty members recruited as part of these initiatives.
For nearly two decades, I have been active in external professional service focused on facilitating sustainable practices in the chemical process industries, including the use of biomass as a renewable feedstock to produce chemicals and fuels. I have served on several national and regional technical panels including the NSF/EPA panels on environmentally benign processing, and the Midwest Biomass Research & Development Initiative Roadmap panel. I served as the President of the International Symposia for Chemical Reaction Engineering (ISCRE, Inc.) during 2011-2012, and currently serve on the Board of Directors of the Organic Reactions Catalysis Society (ORCS). I have served on the scientific and organizing committees of several international symposia in catalysis and reaction engineering, co-chairing the 18th International Symposium on Chemical Reaction Engineering (ISCRE-18, Chicago, 2004), the 2nd North American Symposium on Chemical Reaction Engineering (NASCRE-2, Houston, 2007) and the 2nd and 3rd Joint India-U.S. Chemical Engineering Conference on Energy and Sustainability (Chandigarh, 2008; Mumbai, 2013).
I currently serve as Associate Editor of ACS Sustainable Chemistry and Engineering, a new ACS journal launched to archive research advances in sustainability-related research in the chemistry and chemical engineering disciplines. I also serve on the editorial boards of Industrial and Engineering Chemistry Research (past), Applied Catalysis B, Canadian Journal of Chemical Engineering, and Chemical Engineering Technology.
Archival Journal Publications
Sustainable Catalysis in Supercritical Fluids and Gas-Expanded Liquids (Reviews/Perspectives)
- B. Subramaniam and M. A. McHugh, "Reactions in Supercritical Fluids - A Review," Industrial and Engineering Chemistry Process Design and Development, 25, 1-12 (1986)
- 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, 279-292 (2002).
- P.G. Jessop and B. Subramaniam, “Gas-Expanded Liquids,” Chemical Reviews, 107, 2666-2694 (2007).
- B. Subramaniam, B. Subramaniam, “Gas-Expanded liquids for sustainable catalysis and novel materials,” Coordination Chemistry Reviews, 254, 1843-1853 (2010).
- B. Subramaniam and G. R. Akien, “Sustainable Catalytic Reaction Engineering with Gas-Expanded Liquids,” Current Opinion in Chemical Engineering. 1 (3), 336-341 (2012).
- B. Subramaniam, R. V. Chaudhari, A. S. Chaudhari, G. R. Akien and Z. Xie, “Supercritical Fluids and Gas-expanded Liquids as Tunable Media for Multiphase Catalytic Reactions,” Chemical Engineering Science. 115, 3-18 (2014).
- B. Subramaniam, “Perspectives on Exploiting Near-Critical Fluids for Energy-Efficient Catalytic Conversion of Emerging Feedstocks,” The Journal of Supercritical Fluids, 96, 96-102 (2015).
- B. Subramaniam, R. K. Helling and C. J. Bode, “Quantitative sustainability analysis: A powerful tool to develop resource-efficient catalytic technologies,” ACS Sustainable Chemistry and Engineering (Invited Feature Article), 4, 5859-5865 (2016)
- B. Subramaniam, “Chemical Process Intensification with Pressure-Tunable Media,” Theoretical Foundations of Chemical Engineering, 51(6), 928-935 (2017).
Stabilizing the Activity of Porous Isomerization Catalysts with Supercritical Reaction Media
- S. Saim and B. Subramaniam, "Isomerization of 1-hexene on a Pt/g-Al2O3 Catalyst 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 Journal, 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).
Intensifying Hydrogenations, Syngas Reactions in Conventional and Near-critical Reaction Media
- 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).
- 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).
- J. W. Ford, R. V. Chaudhari and Bala Subramaniam, “Supercritical Deoxygenation of a Model Bio-oil Oxygenate,” Industrial & Engineering Chemistry Research, 49, 10852-10858 (2010).
- H. Wan, R. V. Chaudhari and B. Subramaniam, “Aqueous Phase Hydrogenation of Acetic Acid and Its Promotional Effect on p-Cresol Hydrodeoxygenation,” Energy & Fuels. 27, 487-493 (2013).
- X. Jin, D. Roy, B. Subramaniam and R. V. Chaudhari, “Atom Economical, Aqueous Phase Conversion (APC) of Biopolyols to Lactic Acid, Glycols and Linear Alcohols using Supported Metal Catalysts,” ACS Sustainable Chemistry and Engineering, 1(11),1453-1462 (2013).
- H. Wan, A. Vitter, R. V. Chaudhari and B. Subramaniam, “Kinetic Investigations of Unusual Solvent Effects During Ru/C Catalyzed Hydrogenation of Model Oxygenates,” Journal of Catalysis, 309, 174-184 (2014).
- X. Jin, J. Shen, W. Yan, M. Zhao, P. S. Thapa, B. Subramaniam and R. V. Chaudhari, “Sorbitol Hydrogenolysis over Hybrid Cu/CaO-Al2O3 Catalysts: Tunable Activity and Selectivity with Solid Base Incorporation,” ACS Catalysis. 5, 6545–6558 (2015).
- X. Jin, P. S. Thapa, B. Subramaniam, R. V. Chaudhari, “Microkinetic Modeling of Pt/C Catalyzed Aqueous Phase Glycerol Conversion with In Situ Formed Hydrogen,” AIChE J. 62, 1162–1173 (2016).
- X. Jin, P. S. Thapa, B. Subramaniam and R. V. Chaudhari, “Kinetic Modeling of Sorbitol Hydrogenolysis over Bimetallic RuRe/C Catalyst,” ACS Sustainable Chemistry and Engineering, 4(11), 6037-6047 (2016).
Sustainable Catalysis and Reactor Engineering in Gas-expanded Solvents & Conventional Media
- 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, 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, 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, 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, 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 CO2 Media,” Green Chemistry, 8, 972-977 (2006).
- F. Niu and B. Subramaniam, “Particle Fluidization with Compressed CO2: Experiments and Theory,” Industrial & Engineering Chemistry Research, 46, 3153-3156 (2007).
- 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).
- Y. Houndonougbo, K. Kuczera, B. Subramaniam, and B. B. Laird, "Prediction of the Phase Equilibria and Transport Properties in Carbon-Dioxide Expanded Solvents by Molecular Simulation", Molecular Simulation, 33:9, 861-869 (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, 123(1-2), 46-50, (2008).
- Z. Xie, W. K. Snavely, A. M. Scurto and B. Subramaniam, “Solubilities of CO and H2 in Neat and CO2-Expanded Hydroformylation Reaction Mixtures Containing 1-Octene and Nonanal up to 353 K and 9 MPa,” Journal of Chemical and Engineering Data, 54, 1633-1642 (2009)
- H-J Lee, M. Ghanta, D. H Busch and B. Subramaniam, “Towards a CO2-Free Ethylene Oxide Process: Homogeneous Ethylene Epoxidation in Gas-Expanded Liquids,” Chemical Engineering Science, 65, 128-134 (2010).
- X. Zuo, F. Niu, W. K. Snavely, B. Subramaniam and D. H. Busch, “Liquid Phase Oxidation of p-Xylene to Terephthalic Acid at Medium-High Temperatures: Multiple Benefits of CO2-expanded Liquids,” Green Chemistry, 12, 260-267 (2010).
- B. Subramaniam, “Exploiting Neoteric Solvents for Sustainable Catalysis and Reaction Engineering: Opportunities and Challenges,” Industrial & Engineering Chemistry Research, 49, 10218-10229 (2010).
- J. Fang, R. Jana, J. A. Tunge and B. Subramaniam, “Continuous Homogeneous Hydroformylation with Bulky Rhodium Catalyst Complexes Retained by Nano-filtration Membranes,” Applied Catalysis A: General. 393, 294–301 (2011).
- Kongmeng Ye, Hannsjörg Freund, Zhuanzhuan Xie, Bala Subramaniam and Kai Sundmacher, “Prediction of Multicomponent Phase Behavior of CO2-Expanded Liquids using CEoS/GE Models and Comparison with Experimental Data,” Journal of Supercritical Fluids. 67, 41-52 (2012).
- M. Ghanta, H-J Lee, D. H. Busch and B. Subramaniam, “Highly Selective Homogeneous Ethylene Epoxidation in Gas (Ethylene)-Expanded Liquid: Transport and Kinetic Studies,” AIChE Journal. 59, 180-187 (2013).
- Z. Xie, J. Fang, S. K. Maiti, W. K. Snavely, J. A. Tunge and B. Subramaniam, “Continuous Membrane Reactor for Enhanced Hydroformylation in Carbon Dioxide-Expanded Liquids with Effective Rh Retention,” AIChE Journal, 59, 4287-4296 (2013).
- M. Li, F. Niu, X. Zuo, P. D. Metelski, D. H. Busch and B. Subramaniam, “A Spray Reactor Concept for Catalytic Oxidation of p-Xylene to Produce High-purity Terephthalic Acid,” Chemical Engineering Science. 104, 93-102 (2013).
- M. Li, F. Niu, D. H. Busch and B. Subramaniam, “Kinetic Investigations of p-Xylene Oxidation to Terephthalic Acid with a Co/Mn/Br Catalyst in a Homogeneous Liquid Phase,” Industrial and Engineering Chemistry Research. 53, 9017–9026 (2014).
- W. Yan, A. Ramanathan and B. Subramaniam, “Liquid Phase Ethylene Epoxidation Over W-KIT-6 and Nb-KIT-6 Catalysts Using Hydrogen Peroxide as Oxidant,” Catalysis Science and Technology. 4 (12), 4433 – 4439 (2014).
- Z. Xie, G. A. Akien, B. R. Sarkar, B. Subramaniam and R. V. Chaudhari, “Functionalized Polydimethylsiloxane-attached Rh-complexes as Nanofilterable Homogeneous Hydroformylation Catalysts,” Industrial and Engineering Chemistry Research. 54 (43), 10656–10660 (2015).
- M. D. Lundin, A. M. Danby, G. A. Akien, T. J. Binder, D. H. Busch and B. Subramaniam, “Liquid CO2 as a Safer and Benign Solvent for the Ozonolysis of Fatty Acid Methyl Esters,” ACS Sustainable Chemistry and Engineering. 3 (12), 3307–3314 (2015).
- W. Yan, A. Ramanathan, P. D. Patel, S. K. Maiti, B. B Laird, H Thompson and B. Subramaniam, “Mechanistic Insights for Enhancing Activity and Stability of Nb-incorporated Silicates for Selective Ethylene Epoxidation,” Journal of Catalysis. 336, 75-84 (2016).
- X. Zuo, P. Venkitasubramanian, D. H. Busch and B. Subramaniam, “Optimization of Co/Mn/Br-catalyzed oxidation of 5-hydroxymethylfurfural to enhance 2,5-furandicarboxylic acid yield and minimize substrate burning,” ACS Sustainable Chemistry and Engineering, 4, 3659–3668 (2016).
- X. Zuo, A. S. Chaudhari, K. W. Snavely, F. Niu, H. Zhu, K. J. Martin and B. Subramaniam, “Kinetics of 5-Hydroxymethylfurfural Oxidation to 2,5-Furandicarboxylic Acid with Co/Mn/Br Catalyst,” AIChE Journal, 63, 162-171 (2017).
- M. D. Lundin, A. M. Danby, G. R. Akien, P. Venkitasubramanian, K. J. Martin, D. H. Busch and B. Subramaniam, “Intensified and Safe Ozonolysis of Fatty Acid Methyl Esters in Liquid CO2 in a Continuous Reactor,” AIChE Journal, 63(7), 2819-2826 (2017).
- D. Liu, R. V. Chaudhari and B. Subramaniam, “Enhanced Solubility of Hydrogen and Carbon Monoxide in Propane- and Propylene-Expanded Liquids,” AIChE Journal, 24(3). 970-980 (2018).
- A. M. Danby, M. D. Lundin and B. Subramaniam, “Valorization of Grass Lignins: Swift and Selective Recovery of Pendant Aromatic Groups with Ozone,” ACS Sustainable Chemistry and Engineering, 6(1), 71-76 (2018).
Catalysis with Solid Acids in Near-critical and Conventional 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", Industrial & Engineering Chemistry Research, 37, 1243-50 (1998).
- 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, 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).
- V.S.R. Sarsani and B. Subramaniam, “Isobutane/butene alkylation on microporous and mesoporous solid acid catalysts: Probing the pore transport effects with liquid and near critical reaction media,” Green Chemistry, 11, 102-108 (2009).
- K. Gong, T-P Shi, P. A. Ramachandran, K. W. Hutchenson and B. Subramaniam “Adsorption/Desorption Studies of 224-Trimethylpentane in b-zeolite and Mesoporous Materials Using a Tapered Element Oscillating Microbalance (TEOM),” Industrial & Engineering Chemistry Research, 48, 9490-9497 (2009).
- K. Gong, B. Subramaniam, P. A. Ramachandran and K. W. Hutchenson, “Tapered Element Oscillating Microbalance (TEOM) Studies of Isobutane, n-Butane and Propane Sorption in b- and Y-zeolites,” AIChE Journal, 56(5), 1285–1296 (2010).
- Q. Pan, A. Ramanathan, W. K. Snavely, R. V. Chaudhari and B. Subramaniam, “Synthesis and Dehydration Activity of Novel Lewis Acidic Ordered Mesoporous Silicate: Zr-KIT-6,” Industrial and Engineering Chemistry Research. 52, 15481−15487 (2013).
- Q. Pan, A. Ramanathan, W. K. Snavely, R. V. Chaudhari and B. Subramaniam, “Intrinsic Kinetics of Ethanol Dehydration over Lewis Acidic Ordered Mesoporous Silicate, Zr-KIT-6,” Topics in Catalysis. 57 (17), 1407-1411 (2014).
- A. Ramanathan, R. Maheswari and B. Subramaniam, “Facile styrene epoxidation over novel niobium containing cage type mesoporous silicate, Nb-KIT-5,” Topics in Catalysis. 58 (4-6), 314-324 (2015).
- A. Ramanathan, H. Zhu, R. Maheswari, P. S. Thapa and B. Subramaniam, “A comparative study of Nb-incorporated cubic mesoporous silicates as epoxidation catalysts,” Industrial and Engineering Chemistry Research. 54 (16), pp 4236–4242 (2015).
- A. Ramanathan, H. Zhu, R. Maheswari and B. Subramaniam, “Novel Zirconium Containing Cage Type Silicate (Zr-KIT-5): An Efficient Alkylation Catalyst,” Chemical Engineering Journal. 278, 113-121 (2015).
- H. Zhu, R. Maheswari, A. Ramanathan and B. Subramaniam, “Evaporation-Induced Self-Assembly of Mesoporous Zirconium Silicates with Tunable Acidity and Facile Catalytic Dehydration Activity,” Microporous & Mesoporous Materials, 223, 46–52 (2016).
- C. P. Nash, A. Ramanathan, D. A. Ruddy, M. Behl, E. Gjersing, M. Griffin, H. Zhu, B. Subramaniam, J. A. Schaidle and J. E. Hensley, “Mixed Alcohol Dehydration over Brønsted and Lewis Acidic Catalysts,” Applied Catalysis A. General. 510, 110-124 (2016).
- J-F Wu, A. Ramanathan, W. K. Snavely, H. Zhu, A. Rokicki and B. Subramaniam, “Enhanced metathesis of ethylene and 2-butene on tungsten incorporated ordered mesoporous silicates,” Applied Catalysis A. 528, 142–149 (2016).
- S. K. Maiti, A. Ramanathan, W. H. Thompson and B. Subramaniam, “Strategies to Passivate Brønsted Acidity in Nb-TUD-1 Enhance Hydrogen Peroxide Utilization and Reduce Metal Leaching during Ethylene Epoxidation,” Industrial and Engineering Chemistry Research. 56(8), 1999-2007 (2017).
- A. Ramanathan, J-F. Wu, R. Maheswari, Y. Hu and B. Subramaniam, “Synthesis of Molybdenum-Incorporated Mesoporous Silicates by Evaporation-Induced Self-Assembly: Insights into Surface Oxide Species and Corresponding Olefin Metathesis Activity,” Microporous and Mesoporous Materials, 245, 118-125 (2017).
- J-F. Wu, A. Ramanathan and B. Subramaniam, “Novel Tungsten-incorporated Mesoporous Silicates Synthesized via Evaporation-Induced Self-Assembly: Enhanced Metathesis Performance,” Journal of Catalysis, 350, 182-188 (2017).
- H. Zhu, A. Ramanathan, R. V. Chaudhari and B. Subramaniam, “Effects of Tunable Acidity and Basicity of Nb-KIT-6 Catalysts on Ethanol Conversion: Experiments and Kinetic Modeling,” AIChE Journal, 63(7), 2888–2899 (2017).
- K. Y. Nandiwale, A. M. Danby, A. Ramanathan, R. V. Chaudhari and B. Subramaniam, “Zirconium Incorporated Mesoporous Silicates Show Remarkable Lignin Depolymerization Activity,” ACS Sustainable Chemistry and Engineering, 5(8), 7155-7164 (2017).
- A. Ramanathan, H. Zhu, R. Maheswari and B. Subramaniam, “Remarkable Epoxidation Activity of Neat and Carbonized Niobium Silicates Prepared by Evaporation-Induced Self-Assembly,” Microporous and Mesoporous Materials. DOI: 10.1016/j.micromeso.2017.10.049 (2017).
Techno-Economic Analysis and Life Cycle Assessment of Novel Process Concepts
- 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 Media,” Industrial and Engineering Chemistry Research, 46, 8687-8692 (2007).
- K. Gong, S. Chafin, K. Pennybaker, D. R. Fahey and B. Subramaniam, “Economic and Environmental Impact Analyses of Solid-Acid Catalyzed Isoparaffin/Olefin Alkylation in Supercritical CO2,” Industry and Engineering Chemistry Research, 47, 9072-9080 (2008).
- M. Ghanta, T. Ruddy, D. R. Fahey, D. H. Busch, B. Subramaniam, “Is the Liquid-Phase H2O2-based Ethylene Oxide Process More Economical and Greener Than the Gas-Phase O2-based Silver-Catalyzed Process?” Industrial and Engineering Chemistry Research. 52, 18-29 (2013).
- M. Ghanta, D. R. Fahey, D. H. Busch and B. Subramaniam, “Comparative Economic and Environmental Assessments of H2O2-based and Tertiary Butylhydroperoxide-based Propylene Oxide Technologies,” ACS Sustainable Chemistry and Engineering, 1, 268-277 (2013).
- M. Ghanta, D. R. Fahey and B. Subramaniam, “Environmental Impacts of Ethylene Production from Diverse Feedstocks and Energy Sources,” Applied Petrochemical Research. 4, 167-179 (2014).
- M. Li, T. Ruddy, D. R. Fahey, D. H. Busch and Bala Subramaniam, “Terephthalic Acid Production Via Greener Spray Process: Comparative Economic and Environmental Impact Assessments with Mid-Century Process,” ACS Sustainable Chemistry and Engineering, 2, 823–835 (2014).
- Z. Xie and B. Subramaniam, “Development of a Greener Hydroformylation Process Guided by Quantitative Sustainability Assessments,” ACS Sustainable Chemistry and Engineering, 2, 2748−2757 (2014).
- B. Subramaniam, R. K. Helling and C. J. Bode, “Quantitative sustainability analysis: A powerful tool to develop resource-efficient catalytic technologies,” ACS Sustainable Chemistry and Engineering (Invited Feature Article), 4, 5859-5865 (2016).
- C. J. Bode, C. Chapman, A. Pennybaker and B. Subramaniam, “Developing Students’ Understanding of Industrially Relevant Economic and Life Cycle Assessments,” Journal of Chemistry Education, 94 (11), 1798–1801 (2017).
Synthesis of Functional Materials with Near-critical and Conventional Media
- 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, 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. Hänchen, and M. Mazzotti, G. Muhrer and B. Subramaniam, “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, 9698-9699 (2005).
- J. Nguyen, C. A. Johnson, B. Subramaniam and A. S. Borovik, “Nitric Oxide Disproportionation at Mild Temperatures by a Nanoparticulate Cobalt(II) Complex,” Chemistry of Materials, 20(19), 5939-5941 (2008).
- C. A. Johnson, B. Long, V. Day, A.S. Borovik, B. Subramaniam and Javier Guzman, “Enhanced O2 Binding in Co(salen) Nanoparticles: Characterization by In Situ Infrared and X-ray Absorption Spectroscopies,” Journal of Physical Chemistry C., 112, 12272–12281 (2008).
- C. Johnson, S. Ottiger, R. Pini, E. Gorman, J. Nguyen, E. Munson, M. Mazzotti, A.S. Borovik, and B. Subramaniam, “Near-Stoichiometric O2 Binding on Metal Centers in Co(salen) Nanoparticles,” AIChE Journal, 55, 1040-1045 (2009).
- F. Niu, J. Haslam, R. A. Rajewski and B. Subramaniam, “A Fluid-Bed Coating Technology Using Near-critical Carbon Dioxide as Fluidizing and Drying Medium,” Journal of Supercritical Fluids. 66, 315-320 (2012).
- X. Jin, L. Dang, J. Lohrman, B. Subramaniam, S. Ren and R. V. Chaudhari, “Lattice-Matched Bimetallic CuPd-Graphene Nanocatalysts for Facile Conversion of Biomass-Derived Polyols to Chemicals,” ACS Nano. 7(2), 1309–1316 (2013).
- A. Ramanathan, R. Maheswari, B. P. Grady, D. S. Moore, D. H. Barich and B. Subramaniam, “Tungsten-incorporated cage-type mesoporous silicate: W-KIT-5,” Microporous & Mesoporous Materials, 175, 43-49 (2013).
- A. Ramanathan, B. Subramaniam, R. Maheswari and U. Hanefeld, “Synthesis, and characterization of Zirconium incorporated ultra large pore mesoporous silicate, Zr-KIT-6,” Microporous & Mesoporous Materials. 167 207–212 (2013).
- X. Jin, M. Zhao, J. Shen, W. Yan, L. He, P. Thapa, S. Ren, B. Subramaniam, R. V. Chaudhari, “Exceptional Performance of Bimetallic Pt1Cu3/TiO2 Nanocatalysts for Oxidation of Gluconic Acid and Glucose with O2 to Glucaric Acid,” Journal of Catalysis, 330, 323-329 (2015).
- X. Jin, M. Zhao, W. Yan, C. Zeng, P. Bobba, P. S. Thapa, B. Subramaniam and R. V. Chaudhari, “Anisotropic Growth of PtFe Nanoclusters Induced by Lattice-Mismatch: Efficient Catalysts for Oxidation of Biopolyols to Carboxylic Acid Derivatives,” Journal of Catalysis, 337, 272-283 (2016).
- X. Jin, M. Zhao, C. Zeng, W. Yan, Z. Song, P. S. Thapa, B. Subramaniam and R. V. Chaudhari, “Oxidation of Glycerol to Carboxylic Acids Using Cobalt Catalysts,” ACS Catalysis, 6, 4576–4583 (2016).
- B. Subramaniam, S. Saim and M. C. Clark, "In Situ Mitigation of Coke Buildup in Porous Catalysts by Pretreatment of Hydrocarbon Feed to Reduce Peroxide Impurities and Oxygen Impurities", U. S. Patent 5,690,809, Issued Nov. 25, 1997.
- B. Subramaniam and J. D. Snyder, "Method of Conducting Endothermic Reaction in a Packed-Bed Reactor", U. S. Patent 5,710,356, Issued Jan. 20, 1998.
- B. Subramaniam and S. Saim, "In Situ Mitigation of Coke Buildup in Porous Catalysts with Supercritical Reaction Media," U. S. Patent 5,725,756, Issued Mar. 10, 1998.
- B. Subramaniam, S. Saim, R. Rajewski and V. J. Stella, "Methods and Apparatus for Particle Precipitation and Coating Using Near-Critical and Supercritical Antisolvents", U. S. Patent 5,833,891, Issued Nov. 10, 1998.
- B. Subramaniam, S. Saim, R. Rajewski and V. J. Stella, "Methods and Apparatus for Particle Micronization and Nanonization by Recrystallization from Organic Solutions Sprayed into a Compressed Antisolvent", U. S. Patent 5,874,029, Issued Jan. 25, 1999.
- B. Subramaniam and M. C. Clark, "Improved Solid Acid Supercritical Alkylation Reactions Using Carbon Dioxide and/or other Cosolvents", U. S. Patent 5,907,075, Issued May 25,1999.
- B. Subramaniam, D. J. Bochniak and R. Rajewski, “Methods for Continuous Particle Precipitation and Harvesting,”, U. S. Patent 6,113,795, Issued Sep 5, 2000.
- *B. Subramaniam, D. H. Busch, G. Musie and M. Wei, “Homogenous Catalytic Oxidation of Substrates in Organic Media Expanded by Dense Carbon Dioxide,” U.S. Patent 6,448,454 B1, Issued Sept 2002.
- *R. A. Rajewski, B. Subramaniam, W. K. Snavely and F. Niu, “Precipitation of Proteins from Organic Solutions,” U.S.Patent 6,562,952, Issued May 13, 2003.
- *B. Subramaniam, D. H. Busch, G. Musie and M. Wei, “Catalytic Oxidation of Organic Substrates by Transition Metal Complexes in Organic Solvent Media Expanded by Dense Carbon Dioxide,” U.S. Patent 6,740,785, Issued May 25, 2004.
- B. Subramaniam, C. J. Lyon, “Pressure-tuned solid catalyzed heterogeneous chemical reactions,” U.S. Patent 6,924,407, Issued August 2, 2005.
- *B. Subramaniam, J. A. Tunge, H. Jin and A. Ghosh. “Tuning Product Selectivity In Catalytic Hydroformylation Reactions With CO2-Expanded Liquids,” U. S. Patent 7.365,234, Issued April 29, 2008.
- *D. H. Busch, B. Subramaniam, H.J. Lee, T-P.Shi, “Process for Selective Oxidation of Olefins,” U.S. Patent 7,649,101, Issued Jan 19, 2010..
- *R. A. Rajewski, B. Subramaniam and F. Niu, “Precipitation of Small Medicament Particles into Use Containers,” U. S. Patent 7,744,923, Issued June 29, 2010.
- *B. Subramaniam, D. H. Busch, H-J. Lee, M. Ghanta and T-P. Shi, “Process for selective oxidation of olefins to epoxides,” US Patent application 11/586,061, Allowed August 9, 2011.
- R. A. Givens, C. C. Ma, D. H. Busch, B. Subramaniam and B. Rajagopalan, “Cobalt-Catalyzed Oxidations in Volumetrically Expanded Liquids by Compressed Gases,” US Patent 8,115,029 B2, Issued Feb 14, 2012.
- *J. M. Jonas, R. A. Rajewski, B. Subramaniam and K. F. Terranova, “Compositions and Methods for Delivery of Poorly Water Soluble Drugs and Methods of Treatment,” U. S. Patent 8,221,779, Issued July 17, 2012.
- R. V. Chaudhari, D. Roy, B. Subramaniam, “Nano-metal Catalysts for Polyol Hydrogenolysis,” U. S. Patent 8252963, Issued Aug 28, 2012.
- B. Subramaniam, A. S. Borovik, and C. A. Johnson "O2 Binding of Nanoparticulate Metal Complexes", U. S. Patent 8,268,048, Issued Nov 18, 2012.
- R.V. Chaudhari, D. Roy, and B. Subramaniam, “Polyol Hydrogenolysis by In-Situ Generated Hydrogen,” U. S. Patent US 8,415,511 B2, Issued Apr 9, 2013.
- *B. Subramaniam, D. H. Busch, A. Danby and T. P. Binder, “Ozonolysis Reactions in Liquid CO2 and CO2-Expanded Solvents,” U. S. Patent 8,425,784 B2, Issued April 23, 2013.
- *B. Subramaniam, R. V. Chaudhari and B. R. Sarkar, “Single solvent gas expanded hydroformylation process,” U. S. Patent 8,822,734 B2, Issued Sept. 2, 2014.
- J. A. Tunge, B. Subramaniam, J Fang and R. Jana, "Polymer-supported Transition Metal Catalyst Complexes and Methods of Use", U. S. Patent 8,921,486, Issued Dec 30, 2014.
- R. V. Chaudhari, B. Subramaniam and D. S. Roy, “Catalyst System and Process for Converting Glycerol to Lactic Acid,” U. S. Patent 9,085,521 B2, Issued July 21, 2015.
- *B. Subramaniam, A. Ramanathan, M. Ghanta and W. Yan, “Alkylene Epoxidation with Mesoporous Catalysts,” U. S. Patent 9,233,244, B2, Issued January 12, 2016.
- *B. Subramaniam, D. Busch and F. Niu, "Spray Process for Selective Oxidation", U. S. Patent 9,238, 608 B2, Issued January 19, 2016.
- *B. Subramaniam, X. Zuo, D. H. Busch and P. Venkitasubramanian, “Spray Oxidation Process for Producing 2,5-furandicarboxylic Acid from Hydroxymethylfurfural,” U. S. Patent 9,586,923 B2, Issued March 7, 2017.
Book Chapters on Reactions in Benign Media
- 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).
- 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).
- 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).
- A. M. Scurto, K. W. Hutchenson, and B. Subramaniam, “Gas-Expanded Liquids (GXLs): Fundamentals and Applications,” 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. pgs. 3-40 (2009).
- D. H. Busch and B. Subramaniam, “Catalytic oxidation reactions in carbon dioxide expanded liquids using the green oxidants oxygen and hydrogen peroxide,” 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., pgs. 145-190 (2009).
- J. G. Nguyen, C. A. Johnson, S. Sharma, B. Subramaniam and A. S. Borovik, “Green Methods for Processing and Utilizing Metal Complexes,” 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., pgs. 274-289 (2009).
- B. Subramaniam and J. W. Ford, "Supercritical Phase Catalysis – Heterogeneous," Encyclopedia of Catalysis, 2nd Edition, John Wiley, NY; DOI: 10.1002/0471227617.
- Bala Subramaniam, “Gas-Expanded Liquids for Sustainable Catalysis,” in Encyclopedia of Sustainability Science and Technology, Robert A. Meyers (Ed.), Springer, New York.