نتایج جستجو برای: silica supported catalyst

تعداد نتایج: 268773  

2016
Galip Akay

A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV) induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state c...

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...

Journal: :iranian journal of catalysis 2012
abdolhamid bamoniri bibi fatemeh mirjalili abbas ali jafari fatemeh abasaltian

silica supported phosphorus pentoxide (p2o5·sio2) is an efficient catalyst for synthesis of 1,3,5-substituted pyrazoles via the condensation of 1,3-diketones and hydrazines. simplicity of procedure, mild condition, being solvent-free, high yields, and easy workup are some advantages of this protocol.

Journal: :organic chemistry research 0
neda ayashi chemistry department, collage of science, shahid chamran university of ahvaz, ahvaz, iran mehdi fallah-mehrjardi department of chemistry, payame noor university, tehran, 19395-4697, iran ali reza kiasat a chemistry department, collage of science, shahid chamran university of ahvaz, ahvaz, iran

the use of a recyclable phase transfer catalyst, sio2-peg-imbr, is demonstrated in a simple and highly efficient synthesis of phenacyl derivatives by nucleophilic substitution reaction of phenacyl halides with different anions in water. advantages of this system are easy work-up, moderate to good yields, and recyclable catalyst. the catalyst can be recycled and reused several times with no loss...

Bis(2-R-ind)ZrCl2 (R: H or phenyl) was supported on different types of silica by in situ impregnation method and used for ethylene polymerization. In this method, the step of catalyst loading on support was eliminated and common alkyl aluminum (triisobutylaluminum, TiBA) cocatalyst was used instead of expensive methyl aluminiumoxane (MAO) cocatalyst in the polymerization. The effect of surface ...

Journal: :Chemical & pharmaceutical bulletin 2008
Biswanath Das Martha Krishnaiah Keetha Laxminarayana Duddukuri Nandankumar

Silica supported phosphomolybdic acid, an eco-friendly heterogeneous catalyst, has been found to be highly efficient for Friedlander synthesis of quinolines in excellent yields. A variety of ketones afford the quinolines smoothly. The catalyst can be easily recovered and reused.

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...

Journal: :iranian journal of catalysis 2012
javad safaei-ghomi safura zahedi mohammad ali ghasemzadeh

an efficient green route for the preparation of naphthoxazinones, applying a three-component one-pot condensation reaction of 2-naphthol, aromatic aldehyde and urea in the presence of nano silica supported ferric chloride under solvent-free conditions has been developed. the present procedure offers several advantages such as short reaction time, simple workup, recovery and reusability of the c...

Journal: :Chemical communications 2006
Sailendra Nemana Bruce C Gates

Silica-supported tantalum clusters (on average, approximately tritantalum) were formed by the treatment, in either H(2) or ethane, of adsorbed Ta(CH(2)Ph)(5); the supported catalyst is active for ethane conversion to methane and propane at 523 K, with the used catalyst containing clusters of the same average nuclearity as the precursor.

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...

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