Journal of Molecular Catalysis A-Chemical, Vol.408, 48-59, 2015
Novel heterogeneous catalyst systems based on Pd(0) nanoparticles onto amine functionalized silica-cellulose substrates [Pd(0)-EDA/SCs]: Synthesis, characterization and catalytic activity toward C-C and C-S coupling reactions in water under limiting basic conditions
Novel heterogeneous catalyst systems based on the immobilization of Pd(0) nanoparticles onto ethylene diamine functionalized silica-cellulose substrates [Pd(0)-EDA/SCs] are reported with a view to introduce new synthetic routes under base-free conditions. The base functionalized organic/inorganic hybrid provides specific basic sites for the reactions to occur under base-free or less basic conditions, and that too with excellent yields. Moreover, the basic nitrogen sites present on the substrate can effectively stabilize and enhance the activity of Pd(0) nanoparticles by preventing their agglomeration and controlling their size. All the catalysts were characterized by TGA and FTIR analysis and the most active catalyst, [Pd(0)-EDA/SC-2] was further characterized by SEM, TEM, HRTEM, EDX, CHN and XRD studies. Additionally, it is shown that the Pd(0)-EDA/SCs exhibits excellent activity under limiting basic conditions for the C-C and C-S coupling reactions employing water as the "Green solvent". Furthermore, the novel catalyst could be recovered in a facile manner from the reaction mixture and could be reused up to five times without significant loss of catalytic activity. (C) 2015 Elsevier B.V. All rights reserved.
Keywords:Heterogeneous catalysis;Pd;Nanoparticles;Base functionalization;C-Cand C-S couplings;Green solvent