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№ 37



Отчет о научно-организационной деятельности в 2005 году

Приоритеты по катализу в России

Важнейшие научные достижения
в области катализа за 2003-2005 гг

За рубежом

Отчет о научно-организационной деятельности в 2005 году

Переход к элементу


Приоритеты по катализу в России

Переход к элементу


Важнейшие научные достижения в области катализа за 2003 -2005 гг.

Переход к элементу


За рубежом

Переход к разделу



E.V. Murphree
Award in Industrial & Engineering Chemistry

Sponsored by Exxon Mobil Research & Engineering Co. and Exxon Mobil Chemical Co.

Liang-Shih Fan, Distinguished University Professor and C. John Easton Professor of Engineering at Ohio State UniversityТs department of chemical and biomolecular engineering, has devoted his career to the theory and application of fluidization, multiphase flow, powder reaction engineering, and powder technology. These areas are of relevance to energy and environmental systems and of direct interest to chemical, petrochemical, mineral, and material industries.

Specifically, the 58-year-old chemical engineer is being honored for his pioneering contributions to the theory and practice of fluidized-bed technologies, including his invention and commercialization of two clean-coal processes: OSCAR (Ohio State Carbonation Ash Reactivation) and CAR-BONOX (carbon-based NOx reduction technology), which have been described as good choices for power plants that burn the high-sulfur coals of the eastern U.S.

So far, the strategic fluidization operations developed by Fan have been incorporated into a number of commercial fluidized-bed systems, including multisolid fluidized-bed coal combustors as well as fluidized-bed reactors for production of acrylonitrile and maleic anhydride.

FanТs research career has been distinguished by many "firsts." Among these, he pioneered the development of the first three-dimensional electrical capacitance volume tomography for instantaneous and simultaneous flow-field visualization and quantification for gas-liquid, gas-solid, and gas-liquid-solid fluidization systems. His study led to his discovery of a coherent
3-D flow structure and identification of a new three-phase fluidization regime known as the "helical-vortical regime."

He also developed a novel transparent high-pressure and high-temperature flow rig for multiphase flow research. The rig has been used to derive widely recognized high-P and high-T bubble dynamic theories and to develop experimental techniques for in situ physical property measurements for industrial reactor systems.

His contributions in powder reaction engineering are immense and include one of the most important discoveries in recent years in sorbent reaction chemistry. Specifically, his marker and isotope experiments led to the discovery of the outward ionic diffusion mechanism underlying the reaction of SO2 with CaO powder.

Fan earned a B.S. degree from National Taiwan University and M.S. and Ph.D. degrees from West Virginia University, all in chemical engineering. He did three years of postdoctoral research and earned an M.S. in statistics from Kansas State University before joining the Ohio State faculty in 1978.

At Ohio State, Fan has risen through the ranks and served as department chair from 1994 to 2003. In 2005, he was awarded the Joseph Sullivant Medal, which is given only once every five years and is the highest honor that Ohio State can bestow upon one of its alumni or faculty for eminent achievement.

He was elected to the National Academy of Engineering in 2001. Among his other recognitions, Fan received the Malcolm E. Pruitt Award of the Council for Chemical Research in 2000, the American Society for Engineering Education Chemical Engineering Division Union Carbide Lectureship Award in 1999, and the American Institute of Chemical Engineers Alpha Chi Sigma Award for Chemical Engineering Research in 1996.

Fan has authored or coauthored three books, 20 book chapters,
14 patents, 290 refereed papers, and 250 conference papers. The award address will be presented before the Division of Industrial & Engineering Chemistry.

Linda raber
С & EN / FEBRUARY 6, 2006

ACS Award in Colloid & Surface Chemistry

Sponsored by Procter & Gamble

The physical and chemical processes governing the behavior of complex fluids such as colloidal and polymer solutions result from a delicate balance of weak forces. Although they are subtle in detail, the properties of such "macromolecular" liquids are important in wetting, self-assembly, microfluidic control, and many biological processes. Alice P. Gast has made seminal contributions in understanding these processes and their influence on bulk properties through a combination of colloid science, polymer physics, and statistical mechanics.

Gast, 47, is the Robert T. Haslam Professor of Chemical Engineering and vice president for research and associate provost at Massachusetts Institute of Technology, Her research focuses on a wide range of topics including macromolecules at interfaces disorder-order transitions and wetting in colloidal suspensions, magneto-rheological fluids, and microfluidics.

William B. Russel, dean of the graduate school at Princeton University, says of Gast: "Her research program is characterized by her perceptive choice of exciting, but not obvious, problems; exploitation of sophisticated optical microscopy plus light, neutron, and X-ray scattering to probe and visualize structure; effective use of statistical mechanics to model the phenomena of interest; and timely appealing publication in journals of the highest quality."

"My interest is in systems where the intermolecular forces and interparticle forces are sufficient to cause macroscopic property changes," Gast says. "With submicron-sized particlesЧnanoparticles, they are called nowadays Ч there is a lot of surface area, and surface-surface interactions between particles determine macroscopic properties."

Gast says that she has "migrated" during her career from colloidal particle to polymers to lipids and biological molecules that associate into membranes. "Cell membranes and cells are of the same size scale as colloidal particles, and similar forces determine how they will interact," she says. GastТs group is investigating, for example, the unique crystallization properties of proteins tethered to lipid monolayers. In these studies, fluorescence microscopy reveals ordering phenomena of great interest for both biological applications and fundamental physics. Point mutations allow the researchers to alter the protein-protein interactions in a systematic and detailed way and to investigate the molecular basis for the ordering behavior.

"It is a tremendously exciting time in colloid and surface chemistry," Gast says. "We have measurement techniques to measure forces down to piconewtons and smaller, tremendous visualization techniques like atomic force microscopy and fluorescence microscopy, and computational techniques powerful enough to tackle many-body problems. Systems that you study on a computer, you can now actually see in the laboratory. I am tremendously optimistic about the field."

Gast is also deeply involved in policy issues. She is currently cochairing the National Academies Committee on a New Government-University Partnership for Science & Security and serves on the Department of Homeland Security Science & Technology Advisority Committee.

Gast received a bachelor of science degree in chemical engineering from the University of Southern California in 1980 and masterТs and Ph.D. degrees from Princeton University in 1981 and 1984, respectively. She began her career at Stanford University in 1985, becoming a full professor in 1995. She assumed her current position at MIT in 2001. She has received numerous honors during her career, including election to the National Academy of Engineering in 2001.

The award address will be presented before the Division of Colloid & Surface Chemistry.

Rudy Baum
C & EN / FEBRUARY 6, 2006

Новости науки



Polymer membranes could improve efficiency of hydrogen purification

structureHIGHLY BRANCHED Membrane material is a cross-linked network copolymer.

A FAMILY OF POLY(ETHYLENE oxide) materials exhibits "outstanding" performance in removing acid gas impurities from hydrogen feed streams at high pressure, according to researchers at the University of Texas (UT), Austin, and Research Triangle Institute in Research Triangle Park, N.C., who prepared the materials (Science 2006, 311,639).

Hydrogen produced industrially from hydrocarbons contains impurities such as carbon dioxide. Conventional materials for hydrogen purification allow H2 molecules to diffuse through them in preference to larger molecules (C&EN, Oct. 3, 2005, page 49). The process lowers the pressure of H2, which then has to be repressurized Ч at a cost Ч before use.

The novel materials allow H2 purification to be carried out at high pressures. "Any improvement in purification efficiency could reduce the cost of H2 and accelerate its use in energy applications in the future Сhydrogen economyТ" says UT chemical engineering professor Benny D. Freeman.

The polymers are "reverse selective" because acid gases rather than H2 permeate through them. The cross-linked polymers exhibit increasing selectivity for acid gases with increasing acid gas partial pressure, Freeman points out.

The increasing selectivity is remarkable because polymer membranes swell in acid gases, observes Neil B. McKeown, a chemistry professor at Cardiff University, in Wales. "Swelling generally results in lower selectivities at higher pressures because all the gases diffuse faster through the extra space," he explains. "The advantage of the "reverse-selective" type of membrane is that it can operate at pressures that are compatible with the conditions used in H2 production via hydrocarbon reforming."

Michael Freemantle
С & EN / FEBRUARY 6, 2006

Self-heating fuel cell

A propane-burning solid-oxide single-chamber fuel cell that does not need an external heater could potentially be used to operate small portable electrical and electromechanical devices. The fuel cell Ч a thin disk, similar in size and shape to a watch battery Ч was designed by Sossina M. Haile at Caltech and coworkers (Nature 2005, 435, 795). The samaria-doped ceria (SDC) electrolyte is supported on a nickel/SDC anode coated with a porous ruthenium/ceria layer that enhances the catalysis of propane partial oxidation at lower temperatures. The heat released in the process is used to sustain the fuel-cell temperature in the absence of external heating. The partial oxidation of the fuel yields carbon monoxide and hydrogen, which are then electrochemically oxidized at the anode to produce electricity. The authors point out that several hurdles remain but that "these results demonstrate the viability of high-energy-density hydrocarbon fuels for portable power applications."

С & EN / JUNE 13, 2005

EPA rejects request to waive oxygen requirement in gasoline

States that have banned the oxygen-boosting additive methyl tert-butyl ether (MTBE) must continue to use ethanol or another oxygen-boosting additive in cleaner burning gasoline sold in smog-prone areas, EPA determined on June 2. EPA rejected requests from California, New York, and Connecticut to waive a Clean Air Act requirement that cleaner burning, or reformulated, gasoline contain 2 % oxygen by weight. The decision is a significant victory for ethanol manufacturers and corn growers, who produce most of the raw material used to make the alcohol. The three states each banned MTBE in gasoline because the additive is contaminating their drinking water supplies. Instead, they use ethanol as an oxygenate in reformulated gasoline, but say the practice raises the price of the fuel without an accompanying improvement in air quality. In addition, refiners can produce cleaner burning gasoline without oxygen additives, the states say. The requirement for an oxygen additive in reformulated gasoline "can only be waived if a state demonstrates that it prevents or interferes with the stateТs ability to meet national air quality standards," says Jeffrey R. Holmstead, EPA assistant administrator for air and radiation. "California, New York, and Connecticut did not make this demonstration." This marks the second time EPA has rejected a request from California for a waiver (C&EN, June 18, 2001, page 10).

С & EN / JUNE 13, 2005

Borealis makes catalyst moves

Borealis and Novolen Technology Ч a joint venture between ABB (80 %) and Equistar (20 %) Ч have signed a joint development agreement for metallocene-catalyst-based polypropylene. Under the deal, Borealis will also license NovolenТs metallocene technology. Separately, Borealis is launching its Borstar PE 2G technology, which consists of a new catalyst system and process improvements to its conventional Borstar bimodal polyethylene process. The company says the technology permits the tailoring of polyethylene for applications such as flexible packaging.


С & EN / NOVEMBER 7, 2005

EnzymeТs dance may be a key to mechanism

Enzymes are typically thought of as static structures that accelerate reactions by stabilizing transition states. But in findings with implications for catalyst modification and design, researchers now show that the dynamic motions of enzymes during catalysis may be an essential part of their mechanisms and that similar motions may occur even when they are not catalyzing reactions (Nature 2005, 438, 117). Associate professor of biochemistry Dorothee Kern of Brandeis University and coworkers used NMR spectroscopy to study internal motions of the enzyme cyclophilin A. They found that the enzyme shifts between certain conformations during catalysis with a frequency that corresponds to the rate at which product is generated. This finding suggests that the motions are an essential part of cyclophilin AТs catalytic action. They also found that the enzyme makes similar motions in its substrate-free state. "We propose that the preexistence of collective dynamics in enzymes before catalysis is a common feature of biocatalysts and that proteins have evolved under synergistic pressure between structure and dynamics," the researchers write.


С & EN / NOVEMBER 7, 2005

Calculations point to more stable enzymes

Researchers have devised a computational approach to stabilizing enzymes at higher temperatures while preserving catalytic efficiency (Science 2005, 308, 857). The goal is a longer "shelf life" for enzyme reagents that doesnТt sacrifice activity at ambient temperature, says team leader Barry L. Stoddard of the Fred Hutchinson Cancer Research Center, Seattle. In the calculations, residues known to participate in substrate binding and catalysis, as well as their immediate structural neighbors, are held constant, but all other amino acids are fair game for change. In the case of yeast cytosine deaminase, by changing three amino acids, Stoddard and coworkers achieved a 30-fold increase in the half-life of the enzyme at 50 °C without decreasing catalytic efficiency at lower temperatures. The computational strategy for designing more thermally stable enzymes should work for any enzyme with a high-resolution crystal structure and well-known active site, Stoddard says.


С & EN / MAY 9, 2005

Cadmium at enzymeТs center

The first metalloenzyme containing cadmium has been purified from the marine diatom Thalassiosira weissflogii (Nature 2005, 435, 42). Mak A. Saito of Woods Hole Oceanographic Institution, Todd W. Lane of Sandia National Laboratories, and colleagues purified and sequenced the novel cadmium-containing carbonic anhydrase (an enzyme involved in CO2 fixation during photosynthesis) from T. weissflogii grown in seawater. X-ray absorption near-edge spectroscopy of the purified enzyme confirms the presence of a cadmium-binding site. Comparison of the enzymeТs spectra to those of model cadmium compounds suggests that, in the enzyme, cadmium has a roughly tetrahedral geometry and is bound by two or more thiolates. Another recently sequenced diatom also carries a gene for a similar enzyme, suggesting that cadmium carbonic anhydrases might be widely distributed in oceanic microbes, Saito says. Such a biological requirement for cadmium metalloenzymes may explain why the distribution of cadmium in the ocean closely resembles that of major nutrients such as phosphate, he notes.


С & EN / MAY 9, 2005


Absorption spectroscopy on a single molecule

Single-molecule absorption spectroscopy is a measurement tool that, until now, has eluded analytical chemists wishing to probe molecular structure on surfaces. ThatТs because single molecules donТt absorb much light, making detection difficult, and light-induced heating of the sample and of the microscope tip tends to produce enough noise to swamp out the signal. Researchers in the chemistry department and the Beckman Institute at the University of Illinois, Urbana-Champaign, have overcome these problems and have reported single-molecule laser absorption by single-walled carbon nanotubes, as in the 7-nm-long specimen shown (Nano Lett. 2006, 6, 45). According to Martin Gruebele, who spearheaded the research, the new measurement method combines the chemical selectivity of optical absorption spectroscopy and the atomic-scale resolution of a scanning tunneling microscope (STM). When the sample molecule absorbs energy, its electron density changes shape. The STM then measures that shape change. The team cut down on the heat generated, and therefore the excess noise, by using a transparent silicon substrate and by backlighting the area where the STM tip interacts with the sample. Gruebele says the technique is extremely sensitive for measuring molecules optoelectronic properties and for studying energy transfer on surfaces.


С & EN / JANUARY 2, 2006


Catalytic converters may foul air

Automobile catalytic converters have been used for 30 years to greatly reduce air pollution worldwide, but small amounts of their metals have been detected in air, soil, plants, and waterway sediments. Now, elevated levels of metals emitted from catalytic converters have been measured at busy street intersections in Boston in the first major U.S. study of catalyst metals in urban aerosols (Environ. Set. Technol. 2005, 39, 9464). Sebastien Rauch of Chalmers University of Technology, in Sweden, and coworkers used air filters to trap micrometer-sized particles containing the metals and analyzed the samples by inductively coupled plasma mass spectrometry. Average measured concentrations in Boston of platinum, palladium, rhodium, and osmium range from 0.07 to
8.1 pg/m3. These are not yet considered high enough to pose a serious health risk, but they indicate an emerging problem, given that the number of vehicles worldwide is expected to more than double in the next few decades, the researchers note. Established occupational exposure limits of the metals are 1-2 m g/m3.


С & EN / DECEMBER 19, 2005

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