title: Selectivity control in Pt-catalyzed cinnamaldehyde hydrogenation.
abstract: Chemoselectivity is a cornerstone of catalysis, permitting the targeted modification of specific functional groups within complex starting materials. Here we elucidate key structural and electronic factors controlling the liquid phase hydrogenation of cinnamaldehyde and related benzylic aldehydes over Pt nanoparticles. Mechanistic insight from kinetic mapping reveals cinnamaldehyde hydrogenation is structure-insensitive over metallic platinum, proceeding with a common Turnover Frequency independent of precursor, particle size or support architecture. In contrast, selectivity to the desired cinnamyl alcohol product is highly structure sensitive, with large nanoparticles and high hydrogen pressures favoring C = O over C = C hydrogenation, attributed to molecular surface crowding and suppression of sterically-demanding adsorption modes. In situ vibrational spectroscopies highlight the role of support polarity in enhancing C = O hydrogenation (through cinnamaldehyde reorientation), a general phenomenon extending to alkyl-substituted benzaldehydes. Tuning nanoparticle size and support polarity affords a flexible means to control the chemoselective hydrogenation of aromatic aldehydes.
authors: European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK.
authors: Lee J
authors: LJ
authors: Durndell
authors: European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK.
authors: Christopher M A
authors: CM
authors: Parlett
authors: Institute for Materials Research, University of Leeds, Leeds LS2 9JT, UK.
authors: Nicole S
authors: NS
authors: Hondow
authors: European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK.
authors: Mark A
authors: MA
authors: Isaacs
authors: European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK.
authors: Karen
authors: K
authors: Wilson
authors: European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK.
authors: Adam F
authors: AF
authors: Lee