Nanoparticles of gold and palladium (Au-Pd) could lead to a more efficient and environmentally friendly way of producing benzyl benzoate, a chemical compound used widely in the food, pharmaceutical and chemical industries whose applications include a fixative for fragrances, a food additive and a solvent for chemical reactions
The most common method of producing benzyl benzoate is to react benzoic acid with benzyl alcohol. It can also be generated from benzaldehyde. All three starting materials are derived from toluene, a component of crude oil. The manufacture of benzyl alcohol and benzaldehyde requires the use of halogens and acidic solvents, whereas benzoic acid is produced via a more environmentally friendly liquid phase cobalt-catalyzed reaction.
A research team led by Graham Hutchings, professor of chemistry at Cardiff University in Wales in the United Kingdom, and Christopher Kiely, professor of materials science and engineering at Lehigh, has found a way of producing benzyl benzoate directly from toluene in a solvent-free, single-step process using Au-Pd nanoparticles to catalyze the reaction.
“By optimizing the Au-Pd ratio in the nanoparticle, as well as the reaction conditions, we were able to achieve conversion rates of over 95 percent with no conversion to carbon dioxide,” says Hutchings.
Shining a light on particle size and catalytic activity
The researchers reported their finding Jan. 14 in Science magazine in an article titled “Solvent-Free Oxidation of Primary Carbon-Hydrogen Bonds in Toluene Using Au-Pd Alloy Nanoparticles.” The article was coauthored by Hutchings and Kiely and 10 other researchers, including Ramchandra Tiruvalam, a Lehigh Ph.D. candidate working with Kiely.