نتایج جستجو برای: heterogeneous solid acid

تعداد نتایج: 1038811  

2012
Christian Dohmen Thomas Fröhlich Ulrich Lächelt Ingo Röhl Hans-Peter Vornlocher Philipp Hadwiger Ernst Wagner

Gene silencing mediated by small interfering RNA (siRNA) is a novel approach in the development of new cancer therapeutics. Polycations used for nucleic acid delivery still remain heterogeneous compounds, despite continuous progress in polymer synthetic technologies. Here we report the development of a structural defined folic acid polyethylene glycol (PEG) siRNA conjugate accessible via click ...

Journal: :iranian journal of catalysis 2012
asieh yahyazadeh sara hadesinea mohammad saeed daneshmandi

silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 by reaction with aromatic amines at room temperature in good to excellent yields. imidate was prepared by treatment of equimolar quantities of triethyl orthoformate and diaminomaleonitrile in refluxing dioxane. all the compounds were characterized fully by ...

Journal: :iranian journal of catalysis 2013
asieh yahyazadeh farhad shirini fatamah tavakoli

the aryl-(z)-n-[2-amino-1,2-dicyanovinyl]formamidine 2 cyclize in solvent-free conditions and in the presence of a base to give a 5-amino-1-aryl-4-cyanoimidazoles 3. silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 through reaction with aromatic amines at room temperature and in good to excellent yields. ...

Journal: :iranian journal of science and technology (sciences) 2010
m. hosseini-sarvari

a novel and safe method for nitration of phenols, anilines and other aromatic compounds has beenfound to be feasible with alumina sulfuric acid (asa) as catalyst and mg (no3)2.6h2o as nitrating agent inneat water as solvent. the use of water makes this method compatible with the green chemistry approach

2014
Ken Motokura Toshihide Baba Yasuhiro Iwasawa

This chapter deals with acid–base bifunctional heterogeneous catalyst surfaces with organofunctional groups. One of the most important issues for bifunctional heterogeneous catalysis is the coexistence of incompatible catalytic species, such as acid and base, nearby on a same solid particle surface. In nucleophilic reactions, acid–base bifunctional catalysts enable the activation of both nucleo...

ژورنال: مواد پرانرژی 2014
بیات, یداله, زرندی, مریم, صادقی, زهرا, صفردوست, مرتضی,

Abstract: The aim of this research is to provide a convenient and relatively inexpensive preparation method for synthesis of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). TATB is a reasonably powerful explosive in which ts thermal and shock stability is considerably greater than that of any other known energetic material. It is used in military applications because of its significant insensitiv...

Journal: :Chemistry 2008
Ken Motokura Mitsuru Tomita Mizuki Tada Yasuhiro Iwasawa

Acid-base bifunctional heterogeneous catalysts were prepared by the reaction of an acidic silica-alumina (SA) surface with silane-coupling reagents possessing amino functional groups. The obtained SA-supported amines (SA-NR2) were characterized by solid-state 13C and 29Si NMR spectroscopy, FT-IR spectroscopy, and elemental analysis. The solid-state NMR spectra revealed that the amines were immo...

Journal: :iranian journal of catalysis 0
kaveh khosravi faculty of science, department of chemistry, arak university, arak 38156-8-8349, iran. ali reza karimi faculty of science, department of chemistry, arak university, arak 38156-8-8349, iran. shirin naserifar faculty of science, department of chemistry, arak university, arak 38156-8-8349, iran.

alkanedisulfamic acid functionalized silica-coated magnetic nanoparticles (adsa-mnps) were used as effective, low-cost and reusable solid heterogeneous nanomagnetic catalysts for conversion of aldehydes and ketones to corresponding gem-dihydroperoxides and 1,2,4,5-tetraoxanes using aqueous hydrogen peroxide (30% w/w in h2o) at room temperature. these compounds are important key intermediates in...

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