نتایج جستجو برای: Polymeric catalyst

تعداد نتایج: 67474  

2007
Shinichi Itsuno Miyuki Takahashi Yukihiro Arakawa Naoki Haraguchi

Polymer-supported chiral 1,2-diamine derivatives have been prepared. The polymers containing free 1,2-diamine moiety were applied to enantioselective hydrogenation catalyst by combination with RuCl2-BINAP complex. Asymmetric hydrogenation of aromatic ketones was performed by means of the polymeric catalyst derived from these polymers to give the chiral secondary alcohols with high ee in quantit...

Journal: :Organic & biomolecular chemistry 2009
Naoki Haraguchi Keiichi Tsuru Yukihiro Arakawa Shinichi Itsuno

The asymmetric transfer hydrogenation of imines was performed with the use of a polymer-immobilized chiral catalyst. The chiral catalyst, prepared from crosslinked polystyrene-immobilized chiral 1,2-diamine monosulfonamide, was effective in the asymmetric transfer hydrogenation of N-benzyl imines in CH(2)Cl(2) to give a chiral amine in high yield and good enantioselectivity. Furthermore, an amp...

2008
Jan Hájek Mieke Dams Christophe Detrembleur Robert Jérôme Pierre A. Jacobs Dirk E. De Vos

A novel heterogeneous Pd/polymer catalyst containing co-catalytic functional groups catalyses the direct alkenylation of anisole with ethyl trans-cinnamate under oxygen. The properties of the polymeric catalyst were compared to other immobilised catalysts. The activity of the polymeric catalyst typically increased with temperature and oxygen pressure exhibiting the optimal activity up to 100 TO...

Journal: :physical chemistry and electrochemistry 0
farzaneh ebrahimzadeh department of chemistry, marvdasht branch, islamic azad university, marvdasht, iran,

poly (n-bromosuccinimide) (pnbs) as a mild, efficient, non-acidic, polymeric and heterogeneous catalyst was applied for simple conversion of epoxides into thiiranes by treatment with kscn or (nh2)2cs at room temperature. aliphatic and aromatic epoxides converted into their corresponding thiiranes under mild conditions. all reactions proceeded in short reaction times and afforded the correspondi...

Journal: :Environmental Health Perspectives 1997
H N Gray D E Bergbreiter

New methods for the reduction and remediation of hazardous wastes like carcinogenic organic solvents, toxic materials, and nuclear contamination are vital to environmental health. Procedures for effective waste reduction, detection, and removal are important components of any such methods. Toward this end, polymeric smart materials are finding useful applications. Polymer-bound smart catalysts ...

Journal: Journal of Nanoanalysis 2017
Ali Reza Kiasat Jamal Davarpanah,

In the present study, application of porous acidic catalyst functionalized with an imidazoleionic liquid ([SBA-Im]HSO4) as a phase transfer catalyst for the facile preparation of benzylthiocyanates and azides in water has been described. The catalyst has been characterized byFourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmissionelectron microscopy (TEM...

2016
Jakkrit Suriboot Hassan S. Bazzi David E. Bergbreiter

Ruthenium and molybdenum catalysts are widely used in synthesis of both small molecules and macromolecules. While major developments have led to new increasingly active catalysts that have high functional group compatibility and stereoselectivity, catalyst/product separation, catalyst recycling, and/or catalyst residue/product separation remain an issue in some applications of these catalysts. ...

Journal: :journal of sciences, islamic republic of iran 2015
s. ghasemi b. tamami r. teymoori h. allahyari

poly (vinylpyrrolidone)-grafted silica as an organic-inorganic hybrid material was used as an effective heterogeneous polymeric cosolvent catalyst in organic reactions. this modified silica catalyzed nucleophilic displacement of alkyl halides for easy preparation of alkyl thiocyanates, alkyl cyanides, alkyl azides and alkyl aryl ethers. furthermore, the catalyst was applied for the conversion o...

2013
Mohd Bismillah Ansari Eun-Young Jeong Sang-Eon Park

Tirazine based microporous polymeric (TMP) network was found to be an efficient metal-free catalyst for the epoxidation of styrene. The reactions were performed in water as an environmentally benign medium using H2O2 as a green oxidant at ambient temperature. The reaction afforded higher yield with 90% conversion of styrene and 98% selectivity to styrene oxide in 6 h. The triazine based micropo...

Journal: :Chemical communications 2010
Yiqing Sun Chun Li Yuxi Xu Hua Bai Zhiyi Yao Gaoquan Shi

Graphitic carbon nitride, a polymeric catalyst, was immobilized on the surfaces of chemically converted graphene sheets to form a layered composite, which exhibited greatly improved conductivity and electrocatalytic performance on oxygen reduction reaction.

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