Search results for "Recyclable catalyst"
showing 6 items of 6 documents
ChemInform Abstract: Recyclable Catalyst Reservoir: Oxidation of Alcohols Mediated by Noncovalently Supported Bis(imidazolium)-Tagged 2,2,6,6-Tetrame…
2014
Organic synthesis of high added value molecules with MOF catalysts
2020
Recent examples of organic synthesis of fine chemicals and pharmaceuticals in confined spaces of MOFs are highlighted and compared with silica-based ordered porous solids, such as zeolites or mesoporous (organo)silica. These heterogeneous catalysts offer the possibility of stabilizing the desired transition states and/or intermediates during organic transformations of functional groups and (C-C/C-N) bond forming steps towards the desired functional high added value molecular scaffolds. A short introduction on zeolites, mesoporous silica and metal-organic frameworks is followed by relevant applications in which confined active sites in the pores promote single or multi-step organic synthesis…
Recyclable Catalyst Reservoir: Oxidation of Alcohols Mediated by Noncovalently Supported Bis(imidazolium)-Tagged 2,2,6,6-Tetramethylpiperidine 1-Oxyl
2013
Bis(imidazolium)-tagged 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) catalysts were adsorbed on different supports such as silica gel, silica gel modified with highly cross-linked polymeric imidazolium networks, and highly cross-linked polymeric imidazolium networks entrapping magnetic particles. These systems provided a convenient tool for the oxidation of both primary and secondary alcohols working as recyclable reservoirs for the bis(imidazolium)-tagged TEMPO catalysts. By using EPR spectroscopy it was demonstrated that the catalyst was released as the corresponding oxoammonium salt in the solution during the recycling step, thus promoting the oxidative process in a homogeneous fashion. …
Polypyrrole–palladium nanoparticles composite as efficient catalyst for Suzuki–Miyaura coupling
2012
International audience; Synthesis of a new hybrid material (Pd/PPy) composed of polypyrrole globules with uniformly incorporated Pd nanoparticles via direct redox reaction between pyrrole and Pd(NH3)(4)Cl-2 in water has been recently reported (V.A. Zinovyeva, M.A.Vorotyntsev, I. Bezverkhyy, D. Chaumont, J.-C. Hierso, Adv. Funct. Mater. 21 (2011) 1064-1075). In the actual study, this procedure has been extended to synthesize a series of Pd/PPy powders with variable palladium content and morphological parameters. Depending on the monomer-to-oxidant ratio in reaction mixture, average diameters of Pd and PPy particles may change in the ranges of 1.25-1.45 and 27-62 nm, respectively, the Pd conc…
Organocatalysts and metal-based catalysts: a journey toward the development of new catalytic materials
2015
Organocatalysis and metal-based catalysis represent two of the main pillars of catalytic reactions and have witnessed a huge interest in the last decade. Immobilization, recovery and reuse of these catalysts is of primary importance because of the large amount used especially in the case of organocatalysts. On the other hand, metal-based catalysts must be recovered even if used in low amount, in order to avoid contamination of the product. In this context, we started several years ago investigations on the use of supported ionic liquid phases for the asymmetric organocatalysis mediated by proline.1 This approach is an example of a “release and catch” catalytic system.2 Starting from this ex…
ChemInform Abstract: Water-Soluble Palladium Nanoparticles: Click Synthesis and Applications as a Recyclable Catalyst in Suzuki Cross-Couplings in Aq…
2011
Polyethylene glycol-tagged macrocycle (I) is prepared by a three-fold copper-catalyzed [3 + 2] cycloaddition reaction.