JOHN H. SINFELT: 18 FEBRUARY 1931 - 28 MAY 2011.

JOHN SINFELT was a chemist and chemical engineer wrapped up in one. He brought the approach of an academic scientist probing fundamental issues to bear on challenging technical problems of great practical import. In so doing, he led and inspired small technical groups, many of whose members went on to be leaders themselves. Over his career, he made discoveries that had major benefit to society and brought him high honors.Sinfelt was born in the hamlet of Munson in Clearfield County, which is near the geographic heart of Pennsylvania. Both his father and grandfather were coal miners. As a child, he was initially taught in a two-room schoolhouse in Munson, where his intellectual abilities were apparent at an early age. Following a short spell at a high school in Philipsburg, Pennsylvania, where he excelled at baseball and American football, he entered Pennsylvania State University at 16 years old, and he earned a bachelor's degree in chemical engineering in 1951.He then transferred to the University of Illinois at UrbanaChampaign, where he earned a master's degree in 1953 and a Ph.D. in 1954, both in chemical engineering. His thesis advisor was Harry Drickamer, who at that time was interested in rates of diffusion of molecules across liquid-liquid interfaces. In 1952, Drickamer and his student Tang had begun studying diffusion using radioactive tracers, a method that gave clean, precise results. With Drickamer, Sinfelt continued using this method to investigate the effect of molecular properties on the resistance of a liquid-liquid interface. Drickamer, who later received the U.S. National Medal of Science, was an exceptionally versatile practical scientist who occupied chairs in chemistry, physics, and chemical engineering at Illinois. As illustrated by the diffusion studies, Drickamer employed basic physical methods to study fundamental questions of chemistry. Sinfelt and Drickamer were true kindred spirits. Indeed, Sinfelt's research style, seeking to understand the fundamental science of chemical processes, characterized his work and was responsible in large measure for the major advances Sinfelt brought about. Sinfelt never ceased to sing Drickamer's praises and acknowledge his powerful intellectual influence (which lasted more than 30 years after Sinfelt joined the Esso [Exxon] Research and Engineering Company).In practical scientific terms, the greatest contribution that Sinfelt made was to facilitate the more rapid introduction of lead-free petrol (gasoline), which earned him the U.S. National Medal of Science (presented by Jimmy Carter in 1979). It is relevant to recall that, up to some 20 years ago, massive quantities of a volatile compound, tetraethyl lead, were used as additives to boost the octane rating of petrol to prevent its premature detonation (known as knocking). But the toxicity associated with lead pollution from engine exhaust is so serious that its use was first discouraged and later banned in most countries.On the basis of prolonged and meticulous laboratory-oriented studies (carried out at Standard Oil Development Company, now ExxonMobil Research and Engineering), in which he used a combination of straightforward kinetic measurements and sophisticated synchrotron-based techniques, such as X-ray absorption spectroscopy, to characterize the catalysts that he devised, Sinfelt arrived at extremely efficient nanocatalysts. He called these bimetallic catalysts (they were not alloys in the conventional sense), and they proved highly efficient in the chemical process known as reforming, which generates a relatively high proportion of so-called branched hydrocarbons and aromatic molecules (such as benzene). These molecules elevate the octane rating of the resulting fuel and dispense with the need to use tetraethyl lead as an additive. A particularly powerful example of a bimetallic nanocatalyst is one in which platinum (Pt) and iridium (Ir) co-exist as minute particles supported on a high-area, acidic solid such as alumina. …