ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Reactivity of palladium nanoparticles supported on a microemulsion-based organogel network in supercritical carbon dioxide
Kazumitsu Naoe, Tatsuya Ando, Kenta Kawasaki, and Masanao Imai
Department of Chemical Engineering, Nara National College of Technology, 22 Yata, Yamato-Koriyama, Nara 639-1080, Japan
Abstract: Palladium (Pd) nanoparticles were prepared using the phase transfer method and coated with alkylamines as stabilizing agents stably dispersed in nonpolar solvents. Spherical Pd nanoparticles with an average diameter of 4 nm and a relatively narrow size distribution were obtained using hexylamine or dodecylamine, and they were successfully incorporated in microemulsion-based gelatin organogel (OG); also, an OG network containing Pd nanoparticles was prepared via drying. For the Mizoroki-Heck cross-coupling reaction of iodobenzene with methyl acrylate in supercritical carbon dioxide, the Pd nanoparticles in the OG network exhibited much higher reactivity than those in powder state. Preparation conditions of OG (e.g., gelatin concentration) affected the apparent reactivity of the supported Pd nanoparticles. The Pd nanoparticles in the OG network with high gelatin concentration were recycled with no appreciable change of reactivity. In contrast, the reactivity of the Pd nanoparticles with low gelatin concentration decreased during recycling.
Keywords: palladium – nanoparticle – organogel – supercritical carbon dioxide
Full paper is available at www.springerlink.com.
Chemical Papers 70 (2) 164–171 (2016)