نتایج جستجو برای: heterogeneous and reusable catalyst

تعداد نتایج: 16853269  

Journal: :nanochemistry research 2016
massomeh ghorbanloo amene mohamadi heidenori yahiro

bis-(l-tyrosinato)copper(ii) was reacted with 3-(chloropropyl)-trimethoxysilane functionalized silica that has infused magnetite to yield a magnetically separable catalyst in which the copper carboxylate is covalently linked to the silica matrix through the silane linkage. the immobilized catalyst has been characterized by spectroscopic studies (such as ft-ir, epr, magnetic measurement, sem) an...

Journal: :iranian chemical communication 2016
mahdieh chegeni ardeshir khazaei shahnaz saednia

nanocrystalline sio2–hclo4, as a newly reported catalyst, has been used as an efficient and reusable catalyst for the synthesis of pyrimidine derivatives. the procedure can be successfully applied to the efficient synthesis of mono substituted pyrimidine derivatives, using triethyl orthoformate, ammonium acetate, methyl ketone derivatives. in practice, this method is a combination of a satisfac...

Journal: :journal of nanostructures 2012
a. bamoniri b. f. mirjalili s. nazemian

two  simple  protocols  for  the  synthesis  of  1,  2,  4,  5-  tetrasubstitutedimidazoles  using  nano-spa  as  a  reusable,  eco-  friendly,  inexpensive,  and  efficient  catalyst  are  reported.  short   reaction  times,  high  yields,  scale-up  and  easy  workup  are  the   advantages of these protocols.

Journal: :iranian journal of catalysis 0
mohammad ali ghasemzadeh department of chemistry, qom branch, islamic azad university, qom, p.o. box 364/37185. i.r. iran. zahra elyasi department of chemistry, qom branch, islamic azad university, qom, p.o. box 364/37185. i.r. iran.

this study introduces a green and efficient method for preparation of biologically-active substituted 4h-pyrans using the one-pot three-component reaction of aromatic aldehydes, dimedone and malononitrile in the presence of cobalt oxide nanoparticles. co3o4 nanoparticles were used as an efficient catalyst for the synthesis of polyhydroquinoline derivatives by the reaction of aromatic aldehydes,...

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: :journal of sciences, islamic republic of iran 2014
s. rezayati s. sajjadifar

a mild and green method has been developed for the preparation of coumarins derivatives through the one-pot reactions. in our study,various phenols and ethyl acetoacetate compound in which we used silica-supported boron sulfonic acid [sio2/b(so4h)3] as a new, highly efficient and tri-functional inorganic brønsted acid catalyst were processed under solvent-free condition and thermal. the catalys...

Journal: :journal of chemical health risks 0
farhad hatamjafari department of chemistry, faculty of science, islamic azad university, tonekabon branch, tonekabon, iran

the present study aimed to use a method for the synthesis of some 3, 4-dihydropyrimidin-2-(1h) - ones/thiones. the study tried to answer the question whether this reaction can be performed without solvent and with new catalyst or not. to find answer to the question, we described a novel protocol for the efficient synthesis of 3, 4-dihydropyrimidin-2-(1h)-one derivatives using aromatic aldehyde,...

In this study, Mn (III) salen complex was synthesized and immobilized onto the graphene oxide, which is modified by 3-chloropropyltrimethoxy silane. Heterogeneous catalyst was characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, fourier transform infrared spectra, nitrogen adsorption−desorption isotherm and atomic absorption spectroscopy. The catalyt...

Journal: :chemistry of solid materials 2015
khalil pourshamsian

a  convenient  and  efficient  one-pot  four-component  synthesis  of  1,  2,  4,  5-tetrasubstituted  imidazoles  using  nano  tio2  as  a  recyclable  catalyst  is  reported.  the results  show  that  the  methodology  has  several  advantages  such  as  low  loading  of catalyst,  excellent  yield,  short  reaction  time,  operational  simplicity  and  solvent-free conditions.

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