Reducing the costs and environmental impact of chemical reactions is an essential goal of many modern chemists. Charles P. Casey, a professor emeritus at the University of Wisconsin at Madison is no exception. On Thursday, professor Casey continued the Dreyfus lecture series by outlining the elaborate and fascinating process that his team of scientists took part in to determine the reaction mechanism of a well-known catalytic process.
Ketones are organic compounds characterized by a specific functional group that contains a carbon atom double-bonded to an oxygen atom and two other carbon atoms. Hydrogenation of ketones involves breaking this double bond and bonding to a nearby hydrogen atom. Hydrogenation significantly alters the chemical structure and reactivity of these compounds. Such a process is useful and often necessary in the chemical industry.
Catalysts not only reduce the energy demands of reactions but are also constantly recycled when the reaction takes place. As a result, chemical catalysts are vital to lowering costs and energy consumption and reducing waste and pollution output.
Casey’s group’s goal was initially to map out the reaction mechanism of Shvo’s catalyst, a substance used in hydrogenation reactions. Casey also hoped to ease the strain of an ongoing energy crisis in the 1970’s and 80’s by studying catalysis. Using sophisticated techniques that measured reaction rates, concentrations of chemicals and thermodynamic quantities, the Casey team (as well as international scientists who proposed their own mechanisms) was able to parse out the complicated sequence of reactions that takes place in the hydrogenation of organic substances by Shvo’s catalyst.
Their work led to the creation of another hydrogenation catalyst built upon a central iron atom, as opposed to the ruthenium metal used in Shvo’s catalyst. As the rarity and complexity of metals increases, so does their cost. According to Casey, “simple metals work best”. By removing the need for the ruthenium metal and replacing it with iron, Casey’s group found a cheaper way to achieve the same catalytic process.
As Casey pointed out, other substances that are cheaper and easier to obtain “would be nice” as alternative hydrogenation agents. “But”, he added, “catalytic reduction is clean. It’s a green process and wastes nothing.” With the growing need for alternative energy sources and the dwindling supply of fossil fuel energy, catalysis will become increasingly important in the chemical industry as it moves toward a more sustainable future.