ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

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

E-mail: naoe@chem.nara-k.ac.jp

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.

DOI: 10.1515/chempap-2015-0189

Chemical Papers 70 (2) 164–171 (2016)