Coupling with robust surfaces is a promising approach to improve the stability and recyclability of highly active molecular catalysts. This study builds on our prior success to deposit a Co(iii) cyclam complex, where cyclam is 1,4,8,11-tetraazacyclotetradecane, on mesoporous silica via a microwave-assisted process. The Co(iii) complex was successfully deposited on the silica surface through rea...

(Received: May 18, 2012; Accepted in Revised Form: February 4, 2013) Abstract: Direct oxidation of benzene to phenol in liquid phase in the medium of methanol, acetone, acetic acid and acetonitrile as a solvent over chromium catalyst supported on highly ordered nanoporous silica (Cr-LUS-1) by H O were examined. The best results obtained from methanol solvent with 20% yield and selectivity of 90...

SiO2/MgCl2 (ethoxide type)/TiCl4 Ziegler-Natta catalysts for use in ethylene polymerization and ethylene/1-hexene copolymerization have been prepared using silica with a supported layer of magnesium ethoxide (Mg(OEt)2) as a catalyst precursor, followed by treating with TiCl4 at different Ti/Mg molar ratios, which showed significant effects on the active centers and pore structures of the cataly...

Additional experimental evidence is presented for in vitro generation of hydroxyl radicals because of redox cycling of environmentally persistent free radicals (EPFRs) produced after adsorption of 2-monochlorophenol at 230 °C (2-MCP-230) on copper oxide supported by silica, 5% Cu(II)O/silica (3.9% Cu). A chemical spin trapping agent, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with ...

Methane conversion strategies that protect methanol via in situ esterification achieve higher yields compared to direct methane without product protection; however, most of these high-yield systems operate under unfavorable conditions. To date, there is very limited work developing heterogeneous catalysts for methane-to-methyl-ester conversion, and studies demonstrating the activity manganese a...

the silica supported platinum nanoparticles was synthesized by using the sol-gel method. the possibility of using diamminedinitro platinum (ii) as pt precursor and effect of metal precursor concentration on the final pt nanoparticle size was investigated. a stable silica sol was prepared via hydrolysis of tetraethyl orthosilicate (teos) as a metal alcoxide and condensation reaction. subsequentl...

Supported metal nanoparticle catalysts are commonly obtained through deposition of metal precursors onto the support using incipient wetness impregnation. Typically, empirical relations between metal nanoparticle structure and catalytic performance are inferred from ensemble averaged data in combination with high-resolution electron microscopy. This approach clearly underestimates the importanc...

Nano-silica supported titanium tetrachloride (TiCl4.SiO2) was prepared and used as an acid catalyst for the 14-aryl or alkyl-14H-dibenzo[a,,j]xanthenesreaction under solvent-free conditions. Compared to the classical 14-aryl or alkyl-14H-dibenzo[a,j]xanthenesreaction conditions, this method consistently has the advantage of excellent yie...

Unusually structure-selective growth of single-walled carbon nanotubes (SWNTs) has been attained using a CVD method with a solid supported catalyst. In this method, CO feedstock disproportionates on silica-supported catalytic nanoclusters of Co that are formed in situ from mixed salts of Co and Mo. The nanotube products are analyzed by spectrofluorimetry to reveal distributions resolved at the ...

The stereoselective reduction of imines with trichlorosilane catalyzed by chiral Lewis bases is a well-established procedure for the synthesis of enantio-enriched amines. Five supported cinchona-based picolinamides have been prepared and their activity tested in a model reaction. The comparison of different supporting materials revealed that polystyrene gave better results than silica in terms ...