Ind. Eng. Chem. Res. 2003, 42, 1535-1536
1535
John Sinfelt: A Pioneer in Catalysis
John Sinfelt spent his boyhood years in the towns of Munson and Philipsburg in central Pennsylvania. After completing high school in Philipsburg in 1947, he was a chemical engineering student at The Pennsylvania State University (Penn State), graduating with a B.S. degree in 1951. He then continued his studies at the University of Illinois, from which he obtained his Ph.D. degree in chemical engineering in 1954, when he was 23 years old. His doctoral studies were carried out under the direction of the late Harry Drickamer, whose research interests were in physical chemistry. At University of Illinois, chemical engineering was, and still is, part of the Department of Chemistry (now the School of Chemical Sciences). Because John had already developed a strong interest in physical chemistry while he was an undergraduate student at Penn State, his experience as a graduate student working with Professor Drickamer at University of Illinois was ideal for him. In the early fall of 1954, John began working in Linden, NJ, at Standard Oil Development Company, known today as ExxonMobil Research and Engineering Company. After doing research and development work in the area of heterogeneous catalysis for almost 42 years, he retired from the company as a Senior Scientific Advisor in early 1996 at the time of his 65th birthday. Sinfelt’s first work in heterogeneous catalysis was concerned with the catalytic reforming process for the
production of high octane number hydrocarbons for gasoline. The work included extensive studies of the kinetics of the various reactions that occurred over the Pt/Al2O3 catalyst then used in the process. The results of these studies led to a much-improved understanding of the chemistry of the catalytic reforming process and were the subject of a series of papers appearing in Journal of Physical Chemistry in the early 1960s. A comprehensive review of the work appeared in Sinfelt’s paper on “Bifunctional Catalysis” in volume 5 of Advances in Chemical Engineering published by Academic Press in 1964. The work marked the beginning of a career-long interest of Sinfelt in the kinetics of catalytic reactions. Several of his papers in this area have appeared in the pages of Industrial and Engineering Chemistry over the years. By the early 1960s, John Sinfelt had already decided to concentrate his research in the area of catalysis by metals, with emphasis on the catalytic specificity of metals and on the structures of metal catalysts. He coordinated his interests in these topics with his interest in reaction kinetics right up to the time of his retirement. In pursuing his interest in catalysis by metals, he turned much of his attention to bimetallic catalysts. Research on these catalysts proved to be very fruitful, from either a scientific or technological point of view. The findings of his early work on bimetallic catalysts
10.1021/ie030038v CCC: $25.00 © 2003 American Chemical Society Published on Web 03/15/2003
1536
Ind. Eng. Chem. Res., Vol. 42, No. 8, 2003
formed the basis for a number of patents. They were also subsequently reported in a succession of papers appearing in Journal of Catalysis during the 1970s and in Sinfelt’s book Bimetallic Catalysts: Discoveries, Concepts, and Applications, published by John Wiley and Sons, New York, in 1983. One of the early findings was concerned with the selectivity of hydrocarbon transformations on metal catalysts. Sinfelt found that the catalytic activities of group VIII metals for fragmentation reactions involving the scission of carboncarbon bonds in hydrocarbon molecules were markedly inhibited by the presence of a group IB metal in the surface. In contrast, the catalytic activities for dehydrogenation reactions, in which the only bonds broken were carbon-hydrogen bonds, were affected very little by comparison. In another finding of the early work, it became clear that bimetallic systems of interest for catalysis were not limited to combinations of metallic elements that were highly miscible in the bulk. This extended enormously the number of possible combinations of metallic elements for consideration in catalytic materials. Work with the ruthenium-copper system, the components of which are totally immiscible in the bulk, provided an excellent example. In this system, the copper forms a chemisorption layer on the surface of the ruthenium (i.e., ruthenium-copper bonds are present at the interface between the two metal components). These findings were readily incorporated within the scope of a general concept introduced by John Sinfelt in the course of the research on bimetallic catalysts, namely, the concept of bimetallic clusters as catalyst entities. In practice, the bimetallic clusters are dispersed throughout the pores of a typical support material and frequently constitute as little as 1% of the total catalyst mass. The demonstration that a material of this kind could be realized in a number of cases with conventional methods of catalyst preparation was important. In some catalysts of great interest, the bimetallic clusters are on the order of 1 nm in size, so that virtually all of the metal atoms are present as surface atoms. Research on bimetallic clusters in this category led Sinfelt to the discovery of a new Pt-Ir reforming catalyst. This catalyst was one of several that found extensive commercial application in catalytic reforming in the 1970s (the others were the Pt-Re and Pt-Sn catalysts introduced by Chevron and Universal Oil Products, respectively). The application of bimetallic catalysts was a key factor in establishing the economic feasibility of “leadfree” gasoline, which, in addition to eliminating the hazard of lead itself in gasoline, was critical for the application of catalysts in automobile exhaust systems for decreasing the emission of other pollutants (carbon monoxide, unburned hydrocarbons, and nitrogen oxides) into the atmosphere. Because lead poisons the catalysts in automobile exhaust systems, it was necessary to have lead-free gasoline widely available to avoid this problem.
The application of bimetallic catalysts in reforming has clearly had an enormous impact on the improvement of our environment. In the mid-1970s, John was introduced to the subject of X-ray absorption spectroscopy by Farrel Lytle of the Boeing Company Research Laboratories and quickly became interested in applying this kind of spectroscopy in studies of the structures of bimetallic clusters. Over a period of about 2 decades extending to the 1990s, he collaborated with Farrel, and with Grayson Via and George Meitzner, in a number of studies of this kind that have contributed extensively to our understanding of bimetallic clusters. In roughly the same period, he entered into a collaborative research effort with Professor Charles Slichter and students at the University of Illinois on the application of nuclear magnetic resonance in a number of investigations related to the area of catalysis by metals. The research produced much new information on supported metal catalysts and on molecules adsorbed on the metal surfaces in such catalysts. John has 45 patents and about 186 publications to his credit. Since his retirement from Exxon in 1996, Sinfelt has maintained his interest in catalysis and in science in general. Although he no longer has his own laboratory, he still participates in research with a couple of colleagues and occasionally coauthors papers with them. During this time, he has written several review papers that have been published and has several others that he still plans to write. For his scientific accomplishments, John has been the recipient of numerous honors and awards, including the National Medal of Science, the Perkin Medal in Chemistry, and the National Academy of Sciences Award for the Industrial Application of Science. He is a member of the National Academy of Sciences, the National Academy of Engineering, and the American Philosophical Society. He is also a Fellow of the American Academy of Arts and Sciences. Throughout his career John has always been quick to acknowledge the valuable contributions of many coworkers to his research and to recognize that little would have been accomplished without these contributions. He has always been equally quick in acknowledging the opportunities, support, and encouragement provided to him by ExxonMobil Research and Engineering Company in pursuing his research interests. He has enjoyed his work immensely, and he feels that he was extremely fortunate to have worked in an era when support for science in industrial catalysis research reached an all-time high. Bal K. Kaul ExxonMobil Research & Engineering Company, 3225 Gallows Road, 6A1906, Fairfax, Virginia 22037 IE030038V
