Modified mesoporous materials as Pd scavengers and catalyst supports*
Cathleen M. Crudden, Kevin McEleney, Stephanie L. MacQuarrie, Alexandre Blanc, Mutyala Sateesh, and Jonathan D. Webb
Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
Abstract: The use of mesoporous molecular sieves (MMSs) modified by mercaptopropyl trimethoxysilane (MPTMS) to scavenge Pd is described. The ordered mesoporous material displays excellent ability to remove Pd from organic and aqueous solutions. After only one treatment, a 500-ppm solution of PdCl2 in water can be reduced to 1 ppb. In addition, the resulting material is an effective, leach-proof catalyst for the Suzuki-Miyaura and Mizoroki-Heck reactions. Thus, the Suzuki-Miyaura reaction can be conducted in water at 80 °C with as little as 3 ppb Pd leaching. Hot filtrations and three-phase tests confirm that the catalyst acts without leaching Pd from the surface.
Keywords: palladium; ordered materials; coupling reactions; heterogeneous; SBA-15; micelle-templated materials.
*Paper based on a presentation at the 16th International Conference on Organic Synthesis (ICOS-16), 11-15 June 2006, Mérida, Yucatán, México. Other presentations are published in this issue, pp. 153-291.