Nanomaterials for Chemical Synthesis

Nanomaterials for Chemical Synthesis

Since its inception, Strem Chemicals UK   has focused on offering unique organometallic compounds for both academic and industrial research purposes. Close relationships with leading researchers in the field have enabled Strem to stay abreast of the latest scientific advances in and regularly add novel chemicals to our product portfolio. Most recently Strem Chemicals has embraced the emerging area of nanotechnology and formed a collaboration with the Max-Planck-Institut fuer Kohlenforschung. A series of nanomaterials, including metal nanoclusters, metal nanocolloids (organosols and hydrosols), metal nanopowders, metal nanoparticles, and magnetic fluids are now available from Strem .

precursor concept

Catalysts play a significant role in the production of chemicals today. Nanomaterials have the potential for improving the efficiency, selectivity, and yield of catalytic processes. The higher surface to volume ratio means that much more of the catalyst is actively participating in the reaction. The potential for cost savings is tremendous from a material, equipment, labour, and time standpoint. Higher selectivity mean less waste and fewer impurities, which could lead to safer drugs and reduced environmental impact.

Nanoscale catalysts have been investigated in a number of reactions. Nanometal colloids have been of particular interest. In the precursor concept, pre-prepared nanometal colloids can be tailored for special applications independently of the support by modifying them with lipophilic or hydrophilic protective coatings. Adsorption onto the support is achieved by dipping the material into a solution of the particles. Surfactant stabilized nanometal colloid catalysts have been found to surpass conventional catalysts for hydrogenation and oxidation reactions. The first intramolecular Pauson-Khand reaction in water was successfully carried out by using aqueous colloidal cobalt nanoparticles as the catalyst.

Metal nanoclusters have also been found to be good catalysts. Nanoparticles supported on polymers have been found to catalyze hydrogenations and carbon-carbon coupling reactions. Colloids of bi-and tri-metallic nanoclusters have been shown to be active and selective catalysts in the Suzuki cross-coupling, Phauson-Khand, and hydrogenation reactions. Metal clusters retain their activity for extended periods of time and over a range of substrates.

Gold nanoclusters have also exhibited catalytic activity for the low temperature oxidation of carbon monoxide, even though bulk gold is inactive.

Metal nanoparticles on a variety of supports have also been investigated as catalysts. Zinc and platinum nanoparticles supported on a zeolite matrix exhibited high aromatizing activity in the conversion of lower alkanes. Nanoscale cobalt particles dispersed in charcoal were used as catalyst for the Pauson-Khand, reductive Pauson-Khand, and hydrogenation reactions.

Other types of nanocatalysts have been studied as well. Nanopowder catalysts composed of silica and platinum nanoparticles exhibited very strong catalytic activity for hydrolyzation reactions. Intra-dendrimer hydrogenation and carbon-carbon coupling reactions took place in a variety of solvents (water, organics, biphasics, supercritical CO2) using dendrimer-encapsulated metal nanoparticles.

 

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