Palladium Nanoparticles in an Ammonium Phase

Significance

Nanoparticles of palladium metal were prepared as an ionic-liquid dispersion in tri(n-octyl)methylammonium chloride. Thus, first, a triphasic reaction media system (A) was formed with isooctane (top phase), tri(n-octyl)methylammonium chloride (middle phase), and water (bottom phase). Pd(PPh₃)₄ was added to the triphasic system, and the resulting mixture was stirred at ambient temperature for 1 h. Palladium black was generated and distributed exclusively in the ammonium phase (B). 1-Decanol was essential as additive to promote the Pd-black formation. Hydrodehalogenation of 4-chloropropiophenone was carried out in the Pd-black-containing triphasic system at 25 °C for 80 min under hydrogen gas to give a quantitative yield of propiophenone (C). The Heck reaction was also examined in the triphasic system.