New Twist on 1930s Technology May Become a 21st Century Weapon Against Global Warming


EMBARGOED FOR RELEASE: Monday, March 26, 2012, 4:45 p.m. Eastern TimeNote to journalists: Please report that this research was presented at a meeting of the American Chemical Society

A press conference on this topic will be held at 2 p.m. Eastern Time, March 26, 2012, in the ACS Press Center, Room 15A, in the San Diego Convention Center. Reporters can attend in person or access live audio and video of the event and ask questions at www.ustream.tv/channel/acslive.

Newswise — SAN DIEGO, March 26, 2012 — Far from being a pipe dream years away from reality, practical technology for capturing carbon dioxide — the main greenhouse gas — from smokestacks is aiming for deployment at coal-fired electric power generating stations and other sources, scientists said here today. Their presentation at the 243rd National Meeting of the American Chemical Society, the world’s largest scientific society, was on a potential advance toward dealing with the 30 billion tons of carbon dioxide released into the air each year through human activity.

“With little fanfare or publicity and a decade of hard work, we have made many improvements in this important new technology for carbon capture,” said James H. Davis, Jr., Ph.D., who headed the research. “In 2002, we became the first research group to disclose discovery of the technology, and we have now positioned it as a viable means for carbon dioxide capture. Our research indicates that its capacity for carbon dioxide capture is greater than current technology, and the process is shaping up to be both more affordable and durable as well.”

The new approach has a back-to-the-future glint, leveraging technology that the petroleum industry has used since the 1930s to remove carbon dioxide and other impurities from natural gas. Davis, who is with the University of South Alabama (USA) in Mobile, explained that despite its reputation as a clean fuel, natural gas is usually contaminated with a variety of undesirable materials, especially carbon dioxide and hydrogen sulfide. Natural gas from certain underground formations, so-called “sweet” gas, has only small amounts of these other gases, while “sour” gas has larger amounts. Natural gas companies traditionally have used a thick, colorless liquid called aqueous monoethanolamine (MEA) to remove that carbon dioxide.

Several problems, however, would prevent use of MEA to capture carbon dioxide on the massive basis envisioned in some proposed campaigns to slow global warming. These involve, for instance, capturing or “scrubbing” the carbon dioxide from smokestacks before it enters the atmosphere and socking it away permanently in underground storage chambers. Vast amounts of MEA would be needed, and its loss into the atmosphere could create health and environmental problems, and it would be very costly.

Davis and his group believe that their new approach avoids those pitfalls. It makes use of a nitrogen-based substance termed an “ionic liquid” that binds to carbon dioxide very effectively. Unlike MEA, it is odorless, does not evaporate easily and can be easily recycled and reused.

Davis also described one important advantage the technology has over many other ionic liquid carbon-capture systems. He explained that the presence of water, like moisture in the atmosphere, reduces the effectiveness of many nitrogen-based ionic liquids, complicating their use. Water is always present in exhaust gases because it is a byproduct of combustion. Davis noted that the liquids prefer to interact with carbon dioxide over water, and thus are not hampered by the latter in real-world applications.

Although cautioning that the final application in power plants or factories may look different, Davis envisioned a possible set-up for power plants that would be similar to the one used in his laboratory. He described bubbling exhaust gas through a tank full of the nitrogen-based liquid, which the system could cycle out and replace with fresh liquid. Removing the carbon dioxide would create a new supply of ionic liquid. Once removed, companies could sequester the carbon dioxide by burying it or finding another way to keep it permanently out of the atmosphere. Others have suggested using captured carbon dioxide in place of petroleum products to make plastics and other products.

Davis suggested that in the future, people might also use the technology on a smaller scale in cars or homes, although he cautioned that these applications were likely a long way away. While his group has not fully explored the possible dangers of the chemicals his technology uses, Davis noted that his compounds are quite similar to certain compounds which are known to be safe for consumer use.

His presentation was part of a symposium on research advances involving “ionic liquids,” strange liquids that consist only of atoms stripped of some of their electrons, with applications ranging from food processing to energy production.

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Abstracts of the presentations appear below.

ABSTRACTS: Amine functionalized ionic liquids for CO2 capture: From the first proof of principle to a deployable technology
James H. Davis, Jr., Professor, Ph.D., University of South Alabama, Chemistry and Chemical and Biomolecular Engineering Departments, 307 N. University Blvd., Mobile, AL, 36688, United States, 251-460-7427, 251-460-7359, jdavis@jaguar1.usouthal.eduIn 2002, we became the first group to disclose the preparation of amine-functionalized ionic liquids and their use in the reversible chemical capture of CO2. Initially developed for use as improved materials for the sweetening of natural gas, growing concern over the contributions of anthropogenic CO2 emissions to global warming quickly came to the fore as a driving rationale for the development of such materials. In this talk, we will discuss the origins of our efforts in this area, as well improvements which we have made in intervening years, without fanfare, that have positioned this technology as a viable, deployable means for CO2 capture.


Research and development of energetic ionic liquids
Tom W. Hawkins, Ph.D., US Air Force Research Laboratory, Space & Missile Propulsion, 10 E. Saturn Blvd, Edwards AFB, CA, 93524-7680, United States, 1.661.275.5449, tommy.hawkins@edwards.af.mil Current research programs are aiming to develop ionic liquids (ILs) as energetic materials for various applications. Such applications for ILs include both propulsion and explosives. Within the propulsion arena, a focus is to replace hydrazine (a highly toxic compound) as a fuel. The approach to replacing hydrazine is the synthesis and development of ILs with substantially less vapor toxicity and superior energy density. Hypergolic bipropellants are defined as fuel and oxidizer combinations that, upon contact, chemically react and release enough heat to spontaneously ignite, eliminating the need for an additional ignition source. The feasibility that an IL can undergo hypergolic ignition with a common oxidizer like nitric acid was demonstrated for the first time in our laboratory a few years ago.1,2 Hazardous characteristics, undesirable physical and chemical properties of such ILs must be identified before further development by a potential user. IL-based fuels and their properties will be discussed (including limited safety and sensitivity, and thermophysical properties).


Ionothermal synthesis of layered and framework alumophosphates
Anja Verena Mudring, Prof. Dr., Ruhr-Universitaet Bochum, Anorganische Chemie I, Festkoerperchemie und Materialien, Bochum, NRW, 44801, Germany, +4915152886217, anja.mudring@rub.de Ionic liquids (ILs) have attracted increasing interest over recent years because of their special properties. Albeit they are currently mostly explored as alternative reaction media in organic synthesis and electrolytes in electrochemistry they offer many advantages for materials synthesis. In 2004, Morris and co-wokers first developed a new synthesis method which they coined “ionothermal synthesis” for preparing alumo-phosphates with different zeotype frameworks, such as SIZ-n, CoPOs , based on the use of ionic liquids or deep eutectic mixtures as both the solvent and the structure-directing agent. Whilst Morris mainly employed short-chain imidazolium halides we explored a wide range of different IL cations and anions in the synthesis of layered and framework alumophosphates. Cations such as pyrrolidinium, pyridinium, ammonium, phosphonium with alkyl-chains from C1 to C16 were employed in the synthesis. Aside from simple halides tetrafluoroborates, hexafluorophosphates, bis(trifluoromethane)sulfonylamide, trifluorosulfonate and other anions were used. Indeed, by changing the ionic liquid different alumophosphates could be obtained. It turns out that not only the ionic liquid but also other reaction conditions such as the temperature program critically determine the reaction product and product distribution. By a careful choice of the reaction parameters we managed to obtain a phase-pure enantiomorphic alumophosphate network. Currently we are exploring the use of such networks as luminescent and magnetic materials.


Protonics in ionic liquids and solids: Putting protons to work
Douglas R MacFarlane, Prof, Monash University, Chemistry, Wellington Rd, Clayton, Victoria, 3800, Australia, 61 3 9905 4540, 61 3 99054540, d.macfarlane@sci.monash.edu.auIonic Liquids and solids that contain labile protons present a unique opportunity to observe and manipulate proton energy levels and dynamics. Processes involving proton transfer are fundamental to many aspects of chemistry and biology and are the crux of many important new technologies that can contribute towards the transition to sustainability. This talk will describe a number of new protonic materials in the field of organic salts, including protic phosphonium salts and a variety of novel choline salts. In these the proton behaviour becomes the key to performance in a range of applications, for example in fuel cell operation, solar water electrolysis and in novel pharmaceuticals.


DeNOx of flue gases by ionic liquid gas absorbers
Rasmus Fehrmann, Prof., Ph.D., Technical University of Denmark, Department of Chemistry, Building 207, Kgs. Lyngby, Copenhagen, 2800, Denmark , +4545252389, rf@kemi.dtu.dk The climate change demands reduced emission of CO2 to the atmosphere especially from mobile and stationary sources like fossil fuel fired power plants. The latter have in the near future to perform CO2 capture and deposition and/or change of fuel to CO2 -neutral biomass, alone or combined with e.g. coal. Flue gas from biomass combustion leads however, to a drastic increase of the potassium salt content causing fast deactivation of the V2O5/TiO2 catalyst traditionally imployed in most power plants. Here we report our latest results concerning an alternative deNOx technology utilizing ionic liquids as selective gas absorbers in a possible end-of-pipe installation. Design of effective ionic liquid NO absorbers, the possible absorption mechanism as well as the absorption capacity versus temperature, NO partial pressure and other components of the simulated flue gas will be addressed. The performance of selected systems as Supported Ionic Liquid Phase absorbers will also be highlighted.


Exploring thermal conformation transitions of N,N'-alkylpyrrolidinium and N,N'-alkylpiperidinium iodide salts
William M Reichert, Assistant Professor, Ph.D., University of South Alabama, Chemistry, 6040 USA Dr. South, Mobile, AL, 36688, United States, 251-460-7430, reichert@jaguar1.usouthal.edu

As the applications incorporating ionic liquids increases, the need to understand the interactions governing their unique properties also increases. To date, it is not a simple matter of picking two ions and predicting their physical properties. The focus of this study is the thermal conformational transitions of a series of N,N'-dialkylpyrrolidinium and N,N'-dialkylpiperidinium iodide salts by single crystal XRD, variable temperature Raman spectroscopy and computational methods. XRD data provides a starting point for studying the cation-anion interaction present in an ionic liquid. By using variable temperature Raman data linked with computational data, one can follow the thermal conformation changes that the cation undergoes. With this data, a diagram of the conformational transitions the cation goes through from solid state to liquid state can be obtained. This information will provide much need insight into the thermal behavior of ionic liquids and will help with predicting the thermal behavior of other ILs.


Ionic liquid-active pharmaceutical ingredients loaded on silica: Solids handling for liquid pharmaceutical forms
Robin D. Rogers, Ph.D., The University of Alabama, Center for Green Manufacturing and Department of Chemistry, 3006D Shelby Hall, 250 Hackberry Lane, Tuscaloosa, AL, 35487, United States, 205/348-4323, 205/348-0823, rdrogers@as.ua.edu Ionic Liquids (ILs, salts that melt below 100 °C) loaded on silica have been studied for gas phase reactions, but they have not been used in solution due to the leaching properties of the ILs and the deactivation of the catalyst. One area where the “Supported Ionic Liquid Phase” (SILP) strategy would be a tremendous advantage would be in the loading of ILs that are intended and necessarily leached in order to carry out their functions, as is the case of ILs of Active Pharmaceutical Ingredients (APIs). We have found that IL-APIs are readily loaded and leached from silica, giving to the material a few advantages including the ability to deliver these liquid salt drugs in solid form as free flowing powders. This presentation will discuss the loading, leaching, and favorable physical and chemical properties exhibited by these IL-APIs in solid form.



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