Abstract The scientific and technical advances in the field of polymer science has been abundant recent years. Amongst various polymeric materials available market, synthesis polyolefins forefront since decades. A major challenge this domain remains attaining stereoregular especially polypropylene (PP) significant efforts were carried out by synthesizing internal donors (ID) aiding catalysts in...

The catalyst Pt-Ta supported on 7-alumina was prepared by impregnation with solution containing compoundsof II21K1.0. and Ta205 The Pt concentration was kept constant at 0.2 vet% while the concentration of thetantalum was 0,4 wt%. The activity and selectivity of catalyst were determined under conditions at 450-500 °Cand 15-30 atm.. with molar ratio H2/C[H,e5 and WH=1.5mL/h for converted n-hepta...

nano-silica supported boron trifluoride (bf3.sio2) is an efficient, reusable and eco-friendly catalyst for chemoselective thioacetalization of aldehydes and ketones. so, this catalyst was applied for transthioacetalization of acetals and acylals into their corresponding 1,3-dithiolanes or 1,3-dithianes  in good to excellent yields. the reactions were carried out at room temperature under solven...

The monosila analogue of the C6Me7+ cation can be accessed by hydride abstraction from (pentamethylcyclopentadienyl)dimethylsilane, Cp*SiMe2H. Treatment of this material with triphenylmethylium tetrakis(pentafluorophenyl)borate in dichloromethane at -50 degrees C produced a single cationic species stable for a day or longer. The presence of a single resonance for the ring methyls and a single r...

A highly efficient and general method for the synthesis of aryloylamido coumarinsderivatives by a three-component condensation of 4-hydroxycoumarin or 4-hydroxy-6-methylpyran-1-one, aryl glyoxals and benzamide in the presence of nano silica supported tin(II) chloride as a heterogeneous catalyst is established. In this method, SnCl2/nano SiO2 wasused as green and reusable catalyst. Excellent yie...

Poly(4-vinylpyridine)-supported copper iodide nanoparticles is reported as a new, green and recyclable catalyst for the synthesis of aryl-14H-dibenzo [a-o] xanthenes under solvent-free conditions. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of their efficiency.

Group VIII B metal oxides supported on gamma-alumina were investigated as catalysts and promoters of MoO3 hydrodesulfurization catalysis. Superior promotion was observed in PbO promoted catalyst compared to that of CoO, the typically accepted promoter. Other metal oxides, SnO and Ho2O3 exhibited reasonable hydrodesulfurization catalysis promotion but lower than for CoO promoted catalyst.

An unusual [1,5]-Brook rearrangement of the lithium alkoxide of geminal bis(silyl) homoallylic alcohol is described. The unique steric and electronic effects of geminal bis(silane) were found to be crucial for promoting this long-range silyl migration, as well as for facilitating the subsequent γ/Z-selective addition of silyl allyllithium with carbonyl compounds to synthesize diverse configurat...

A green, efficient and selective approach for the oxidation of sulfides to sulfoxides and sulfones with UHP at room temperature is reported. The reaction is performed in the presence of vanadia catalyst supported on mesocellular silica foam (MCF) with a V content ranging from 2% to 10% as heterogeneous and reusable catalyst. The structural and textural characterization of this catalyst were don...

the potential of carbon nanotubes (cnt) supported cobalt catalysts for fischer-tropsch (ft) reaction is shown. using the wet impregnation method cobalt on carbon nanotubes catalysts were prepared with cobalt loading varying from 15 to 45 wt. %. the catalysts are characterized by different methods including: bet physisorption, x-ray diffraction, hydrogen chemisorption, and temperature-programmed...