71387-67-2Relevant articles and documents
Catalytic Materials Based on Surface Coating with Poly(ethyleneimine)-Stabilized Gold Nanoparticles
Ortega-Mu?oz, Mariano,Blanco, Victor,Hernandez-Mateo, Fernando,Lopez-Jaramillo, F. Javier,Santoyo-Gonzalez, Francisco
, p. 3965 - 3973 (2017)
Gold nanoparticles (AuNPs) can be obtained from HAuCl4 by using poly(ethyleneimine) (PEI) as both reductant and stabilizing agent. However, the known affinity of PEI for different materials has not been exploited to coat them and turn their surface catalytic. We demonstrate that the irradiation of a solution of HAuCl4 and branched PEI 1800 (bPEI2K) with microwave (MW) yields PEI-stabilized AuNPs (MW-PEI@AuNPs) with an average size of 7.6 nm that are catalytically active in the reduction with NaBH4 of different nitroarenes functionalized with a variety of functional groups. Moreover, the as-prepared MW-PE@-AuNPs show affinity for different materials such as polystyrene (standard spectrophotometry disposal cuvettes), polypropylene (Falcon-type tubes), and silica (Silica gel 60), turning their surface catalytic without any additional synthetic step. This feature was exploited to transform standard tubing (Tygon, poly(ether ether ketone), and stainless steel) into flow reactors by simple passage of a solution of MW-PEI@AuNPs. This straightforward functionalization is especially appealing in the case of the stainless-steel tubing, one of the materials more widely used in HPLC, which is of interest for flow nanocatalysis.
Dual optimization approach to bimetallic nanoparticle catalysis: Impact of M1/M2 ratio and supporting polymer structure on reactivity
Udumula, Venkatareddy,Tyler, Jefferson H.,Davis, Donald A.,Wang, Hao,Linford, Matthew R.,Minson, Paul S.,Michaelis, David J.
, p. 3457 - 3462 (2015/06/16)
A dual optimization approach to nanoparticle catalysis is reported in which both the composition of a bimetallic nanoparticle and the electronic properties of the supporting polystyrene-based polymer can be varied to optimize reactivity and chemoselectivity in nitroarene reductions. Ruthenium-cobalt nanoparticles supported on polystyrene are shown to catalyze nitroarene reductions at room temperature with exceptional activity, as compared with monometallic ruthenium catalysts. Both the identity of the second metal and the M1/M2 ratio show a profound effect on the chemoselectivity of nitroarene reductions. These polymer-supported bimetallic catalysts are shown to react with nearly complete chemoselectivity for nitro group reduction over a variety of easily reducible functional groups. The electronic properties of the supporting polymer also have a significant impact on catalysis, in which electron-deficient polystyrenes enable 100% conversion to the aniline product in just 20 min at room temperature. Polymer effects are also shown to influence the mechanism of the reduction reaction, in addition to accelerating the rate, confirming the impact of the polymer structure on catalytic efficiency. These catalysts are easily prepared in a single step from commercial materials and can be readily recycled without loss of activity.
First Selective Reduction of Aromatic Nitro Compounds Using Water Soluble Catalysts
Tafesh, Ahmed M.,Beller, Matthias
, p. 9305 - 9308 (2007/10/02)
A new methodology has been developed which involves the reduction of substituted nitro aromatics to substituted anilines using a two phase system with water - soluble palladium catalysts.The nitro group was reduced selectively to an amine in up to 85percent yield whereby other functional groups i.e., ketone, nitrile, chloride and alkene were untouched.
