Greener Process Developed for Producing Industrial Chemical

Christopher Kiely (standing) with graduate student Ramchandra Tiruvalam (Lehigh Univ.)

A U.S.-U.K. chemistry and engineering team has developed a more environmentally friendly process for producing benzyl benzoate, a common chemical found in food additives, insecticides, fragrances, and used in other industrial chemical processes. The research was partially funded by the Dow Chemical Company and the findings are published in this week’s issue of the journal Science (paid subscription required).

Most of today’s methods for making benzyl benzoate involve strong chemicals or those made from fossil fuels. The most common method of producing benzyl benzoate is in a chemical reaction when benzoic acid mixes with benzyl alcohol. Benzyl benzoate can also be made from benzaldehyde. All of these starting materials are derived from toluene, a toxic component of crude oil. The manufacture of benzyl alcohol and benzaldehyde also requires the use of halogens and acidic solvents.

A research team led by Graham Hutchings, professor of chemistry at Cardiff University in Wales, and Christopher Kiely (pictured left), professor of materials science and engineering at Lehigh University in Bethlehem, Pennsylvania, has found a way of producing benzyl benzoate directly from toluene in a solvent-free, single-step process with nanoparticles made of a gold and palladium alloy to catalyze the reaction.

The researchers were able to produce and test gold/palladium nanoparticles — a nanometer is one billionth of a meter — as well as optimize the reaction conditions. These methods allowed the team to convert 95 percent of the test material with no conversion to carbon dioxide.

Further tests showed the catalytic nanomaterial had staying power. The researchers report the gold/palladium alloy nanoparticles supported by carbon were able to be reused with little loss of effectiveness. There was also little change in particle shape and size after extended reaction periods.

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