Research

Hydrocarbons, the principal components of oil and natural gas must be chemically altered to make useful products and materials, their production via renewable and sustainable methods is paramount to combat global warming. This is carried out by processes such as isomerization, alkylation homologation, etc. These processes are frequently catalyzed by acids and involve electron deficient intermediates called carbocations.

The Loker Institute has pioneered new methods to study such processes and their mechanisms. Research is also aimed at more efficient utilization of fossil fuel resources including recycling of carbon dioxide (a greenhouse gas) to useful materials. Studies are also directed towards developing new synthetic methodologies. Polymeric materials derived from simple hydrocarbon precursors are the basis for new materials with exceptional electrical, optical, and magnetic properties.

These materials find applications in information technology, photochemical energy conversion, as new biologically active compounds and drugs, and biomedical devices.

In studying hydrocarbons and their conversions a wide variety of highly acidic systems called superacids have been developed. When higher valent Lewis acid fluorides such as SbF5 and TaF5 are combined with Bronsted acids such as HF or FSO3H, acids many billions of times stronger than sulfuric acid are obtained. In such superacidic media the lifetime of carbocations is sufficiently long to be examined by a variety of chemical and physical methods including nuclear magnetic resonance and photoelectron spectroscopy. These intermediates are fundamental to the understanding of acid catalyzed processes.

Organofluorine compounds have found increasing applications in the areas of medicinal chemistry and materials science. There is a concerted effort to develop synthetic methodologies in synthetic fluorine chemistry to synthesize fluoromethyl, difluoromethyl and trifluoromethyl group containing organic molecular scaffolds involving nucleophilic, electrophilic, radical, carbenoid and photochemical pathways. The fluorination protocols involve the use of onium polyhydrogen fluorides that have also been utilized as a safe and stable strong acid medium for alkylation reactions to produce high-octane gasoline, commercially (the so called ALKAD process). Fluorinated Bronsted, Lewis and conjugate superacids also play a major role in in stabilizing carbocations and promoting electrophilic aromatic substitution reactions and superelectrophilc activations.

The Institutes advocates the storage of electrical energy in newly formed chemical bonds and releasing the stored energy through the breaking of these bonds electrochemically, thermally with high roundtrip efficiencies. This research is focused on studying the fundamental and applied aspects of electrochemical systems for energy conversion, energy storage, and electro-synthesis, with the goal of increasing global use of renewably generated electricity. Specifically, we are advancing safe, robust, inexpensive, and sustainable batteries, and the industrial electrochemical manufacturing of iron and steel, fertilizers, polymers, and fuels.

The direct conversion of methane (i.e. natural gas) to higher hydrocarbons and derived products offers a viable alternative to Fischer-Tropsch chemistry. Until recently, the utilization of methane as a chemical building block was limited to free radical reactions (combustion, nitration, chlorination, etc.). Various stoichiometric organometallic insertion reactions were also discovered, but their use is so far not practical. Superacid catalysts permit oxidative condensation of methane to higher hydrocarbons, as well as the selective electrophilic conversion of methane to its monosubstituted derivatives such as methyl halides and methyl alcohol. Monosubstituted methanes can be further condensed to ethylene, propylene and derived hydrocarbons over zeolites or bifunctional acidic-basic catalysts, giving access to the whole range of hydrocarbons essential to our everyday life. Mechanistic aspects of the methane conversion chemistry, particularly the role of pentacoordinate CH5+-type carbocationic intermediates, are also studied.

When hydrocarbons are burned, they form carbon dioxide and water. They are thus non-renewable on the human time scale. Excessive burning of fossil fuels leads to increased atmospheric levels of carbon dioxide, which has been linked to global warming and climatic changes. In addition to trying to keep carbon dioxide levels down through regulations, new solutions are needed. An innovative new approach pursued by the Institute is directed at reversing the process by producing hydrocarbons from carbon dioxide and water via methyl alcohol. Some of the underlying chemistry to convert carbon dioxide using hydrogen gas (obtained by electrolytically splitting water) is already known. Metal or superacid catalyzed reduction has made significant progress to bring about the feasibility of such approach. Electricity needed for generating hydrogen is, however, costly. As we still cannot store electricity efficiently, power plants in their off-peak periods could produce hydrogen as a means of storing electricity. It then can be used to recycle CO2 (from smokestack emissions or the atmosphere) into methyl alcohol and derived fuels. The carbon dioxide recycling technology now under development at the Institute will not only produce useful fuels, but at the same time would help mitigate global warming.

Methyl alcohol and derived fuels can also be used to produce electricity in a new generation of direct oxidation liquid feed fuel cell developed jointly with JPL-Caltech. When operating the fuel cell in its reversed mode, carbon dioxide and water can be electro-catalytically reduced to methyl alcohol. Alternatively, chemistry including that developed at the Institute allows conversion of methyl alcohol into simple olefins (ethylene and propylene), and through them into gasoline, aromatics or practically any other hydrocarbon product we presently derive from oil.

We use organic synthesis and develop new polymerization methods and polymer architectures to address sustainability and materials for alternative energy applications.

We are focused on the design, synthesis, and characterization of electroactive organic polymers, with the primary area of interest being solution processable polymer-based solar cells or photovoltaics. Within this focus, materials are targeted or designed based on the properties desired for a specific application. A central facet of all our projects is to prepare high performing materials in a simple and efficient manner. This makes synthesis a major component of our research, in terms of both preparing new monomers and polymers or preparing known compounds and implementing them in new and creative ways. The entire journey from synthesis to device is performed in-house, making device fabrication, and testing a key method for material characterization.

The Methanol Economy is a concept of developing chemistry to produce and use methanol in place of fossil fuels such as oil and gas. The goal is to develop renewable sources of energy that can help replace U.S. dependence upon fossil fuels (oil, gas, and coal), and to recycle carbon dioxide into new fuels and materials while mitigating manmade effects on climate change. Fossil fuels, oil, natural gas, and coal are major energy sources and the feedstocks for a great variety of hydrocarbon-based manmade materials and products that range from fuels to synthetic materials, plastics, and pharmaceuticals. What nature gave us through eons of formation is being used up rapidly. One needs to search for ways to significantly increase the efficiency with which these precious resources are utilized (conservation) and ways in which to develop new energy sources.

USC’s Loker Hydrocarbon Research Institute under the leadership of Nobel Laureate, Professor George A. Olah and his colleague, Professor G. K. Surya Prakash is developing this new approach (see Beyond Oil and Gas: The Methanol Economy by G. A. Olah, A. Goeppert and G. K. S. Prakash, Wiley-VCH, Weinheim, 2006). Methanol can be efficiently made by directly converting natural gas (i.e., methane) to methanol. Perhaps more importantly, methanol can also be made from carbon dioxide — initially from high concentration exhausts of power plants, and eventually from the carbon dioxide content of the air itself. As the increasing carbon dioxide content of our atmosphere is a main factor in global warming, the Methanol Economy represents a feasible new approach to mitigate the manmade effect of climate change by recycling carbon dioxide into new fuels and materials. Although CO2. is recycled in the atmosphere through photosynthesis, no methods exist for its use as a significant carbon source for fuels or synthetic materials. Such a chemical recycling will also mitigate global warming. CO2 conversion, however, will need energy. The energy may come from alternative sources (solar, wind, hydro, geothermal, etc.) including nuclear energy.

Methanol is an excellent high-octane fuel for internal combustion engines and is an even more efficient fuel in fuel cells. Because it is a liquid at ambient temperatures (Boiling point: 64.6 C), methanol can be readily stored and transported using existing infrastructure. Methanol is readily converted to dimethyl ether (DME, a gas with a boiling point -24.9 C), which is an excellent and clean burning (high cetane number) diesel substitute and can replace LPG and LNG in all their applications. In addition, methanol can be readily converted to ethylene and propylene, which can replace petroleum as the starting material for the manufacture of virtually all the synthetic hydrocarbon products.

A central theme of our research is the study of novel synthetic methods and strategies and their applications to the synthesis of novel molecules that can lead to new therapeutics. A key focus of our efforts is the development of new chemical reactions with elements with diverse reactivity, based on novel chemistry of boron, titanium, and other elements, which are also inexpensive and environmentally safe.

Our multidisciplinary synthetic work is often aided by mechanistic studies, that enhance our understanding of these processes. We are also pursuing the total synthesis of novel organic molecules for potential applications as new therapeutics, based on a variety of synthetic applications with synthetic utility.

The biological properties of our new compounds are studied in collaboration with expect researchers in the field. The exploration of novel synthetic reactions promotes the discovery of new chemistry and produces new substances for biology and medicine. We are also pursuing the synthesis of a variety of novel organic molecules as potential therapeutics. These include the development of novel synthetic reactions that promote the discovery of new chemistry, while they produce new substances for biology and medicine.