The Chemical Effects of Ultrasound
Emeritus Professor Ken Suslick from the University of Illinois Urbana-Champaign will present a seminar.
The Chemical Effects of Ultrasound
Fundamentally, chemistry is the interaction of energy andmatter. Surprisingly, there are relatively few ways of putting energy into molecules. High intensity ultrasound has found numerous applications in driving chemical reactions and in the preparation of unusual materials, creating the field of sonochemistry. The chemical effects of ultrasound originate from acoustic cavitation: the formation, growth, and implosive collapse of bubbles in a liquid. From sonoluminescence spectroscopy, we have established that cavitation produces local conditions inside the bubbles of ~5000 K, ~1000 atm, with heating and cooling rates that exceed 1010K/s. In isolated single bubbles, which can collapse more symmetrically and effectively, temperatures exceeding 20,000 K are observed.In otherwise cold liquids, ultrasound is able to drive reactions that normally occur only under extreme conditions. The sonochemical syntheses of nanostructured metals, alloys, metal carbides, supported heterogeneous catalysts, and nano-colloids derives from the sonochemical decomposition of volatile organometallic precursors during cavitation, which produces clusters a few nm in diameter. Such nanostructured solids are active heterogeneous catalysts for various reactions.Another remarkable phenomenon occurs during ultrasonic irradiation of liquid-solid slurries: extremely high-speed inter-particle collisions. Turbulent flow and shock waves produced by acoustic cavitation can drive metal particles together at sufficiently high velocities to induce melting upon collision. Metal particles that are irradiated in hydrocarbon liquids with ultrasound undergo collisions at roughly half the speed of sound and generate localized effective temperatures of ~3000 K at the point of impact. Consequently, both stoichiometric and catalytic liquid-solid reactions can be tremendously enhanced.In addition, sonofragmentation of molecular crystals occurs readily, which greatly improves the uniformity of particles formed during crystallization, for example, of active pharmaceutical ingredients(APIs). Sonocrystallization has become increasingly important in the pharmaceutical industry for the preparation of APIs.We have developed a mechanistic understanding of the origin of these phenomena and begun to separate the details of the effects of ultrasound on nucleation, mass transport, shockwave fragmentation of crystallites, and inter-particulate collision. Decoupling experiments were performed to confirm that interactions between shockwaves and crystals are the main contributors to crystal breakage.Bang, J. H.; Suslick, K. S. “Applications of Ultrasound to the Synthesis of Nanostructured Materials” Advanced Materials2010, 22, 1039–1059.Zeiger, B. W.; Suslick, K. S. “Sonofragmentation of Molecular Crystals” J. Am. Chem. Soc.2011, 133, 14530-33.Xu, H.; Zeiger, B. W.; Suslick, K. S. “Sonochemical synthesis of nanomaterials” Chem. Soc. Rev.2013,42, 2555-2567.You, S.; Chen, M.-W.; Dlott, D. D.; Suslick, K. S. “Ultrasonic hammer produces hot spots in solids” Nature Commun.2015, 6,6581.Suslick, K. S.; Eddingsaas, N. C.; Flannigan, D. J.; Hopkins, S. D.; Xu, H. “The Chemical History of a Bubble”Accts. Chem. Res.2018, 51, 2169–2178.Barcikowski, S.; Plech, A.; Suslick, K. S.; Vogel, A. “Materials synthesis in a bubble”MRS Bulletin2019, 44, 382-391.Kim, H. N.; Suslick, K. S. Sonofragmentation of Organic Molecular Crystals vs Strength of MaterialsJ. Org. Chem.2021, 86, 13997–14003.
Kenneth S. Suslick is the Marvin T. Schmidt Research Professor of Chemistry at the University of Illinois at Urbana-Champaign. Professor Suslick received his B.S. from Caltech in 1974 and his Ph.D. from Stanford in 1978, and came to the UIUC immediately thereafter. Fromthe Royal Society of Chemistry, He is the recipient of the Centenary Prize, the Theophilus Redwood Award, and the Sir George Stokes Medal, the Materials Research Society Medal, and both the Nobel Laureate Signature Award and the Hildebrand Award in the Chemistry of Liquids by the American Chemical Society. He has also received the Helmholtz-Rayleigh Interdisciplinary Medal of the Acoustical Society of America and the Chemical Pioneer Award of the American Institute of Chemists. In 2018-2019, Suslick was the George Eastman Professor at the University of Oxford and a Fellow of Balliol College. Professor Suslick has published more than 500scientific publications, edited four books, and holds 71 patents and patent applications; his h-index is 130and his publications have been cited more than 64,000 times. Professor Suslick’s two major research areas are the chemical effects of ultrasound and chemical sensing. In addition to his academic research, Professor Suslick has had significant entrepreneurial experience. He wasthe lead consultant for the team that commercialized the first echo contrast agent for medical sonography, Albunex™, which evolved to Optison™. He was also the founding consultant for VivoRx Pharmaceuticals and co-inventor of one of the first FDA-approved nanopharmacueticals, Abraxane, the predominant delivery system for breast cancer chemotherapy. Most recently, Suslick invented, developed and commercialized the “optoelectronic nose”, co-founding Specific Diagnostics, Inc., located in Silicon Valley, which was recently bought by the large French biotech firm, bioMérieux.
An informal tutorial on ’sonochemistry’ will be given in Shelby 2105 from 4-5pm.
Host: Silas Blackstock