نتایج جستجو برای: organic solvent free

تعداد نتایج: 743377  

Journal: :Structure 2003
Shahzad Majeed Gilad Ofek Adam Belachew Chih-chin Huang Tongqing Zhou Peter D Kwong

Suitable conditions for protein crystallization are commonly identified by screening combinations of independent factors that affect crystal formation. Because precipitating agents are prime determinants of crystallization, we investigated whether a systematic exploration of combinations of mechanistically distinct precipitants would enhance crystallization. A crystallization screen containing ...

Journal: :Environmental Health Perspectives 1996
A Iregren

This paper reviews some illustrative examples of studies of human neurobehavioral effects from experimental as well as long-term occupational organic-solvent exposure. My objective is to present a selection of neurobehavioral solvent studies with the educational aim that we may hopefully learn from the early experiences of others. Some of the methodological problems encountered in these studies...

Journal: :iranian journal of science and technology (sciences) 2014
a. r. sardarian

dodecylbenzenesulfonic acid (dbsa) was used as an efficient, cheap and stable brønsted catalyst for acetylation of alcohols and phenols and formylation of alcohols under solvent-free conditions. various primary, secondary and tertiary alcohols were acetylated with acetic anhydride as an acetylating agent under solvent-free conditions in the presence of catalytic amount of dbsa at room temperatu...

Journal: :iranian chemical communication 2013
eshagh rezaee nezhad zahra abbasi mojtaba rahimi moghaddam mohammad ali attaei

the aim of this research is to study ni2+ supported on hydroxyapatite-core-shell magnetic γ-fe2o3 nanoparticles (γ-fe2o3@hap-ni2+) as a green and recyclable catalyst for the biginelli reaction under solvent-free conditions. one-pot multi-component condensation of 1,3-dicarbonyl compounds, urea and aldehydes at 80 oc affords the corresponding compounds in high yields and in short reaction times ...

Journal: :journal of sciences, islamic republic of iran 2014
b. pouramiri e. tavakolinejad kermany h. khajesamani h. khabazzadeh

an improved, simple, and facile synthesis of 3,4-dihydropyrimidin-2(1h)-ones by employing three-component, one-pot condensation reaction of β-keto ester, aromatic aldehydes, and urea or n-methylurea using lacl3/clch2cooh as an inexpensive and green chemistry catalyst system under solvent-free conditions described. compared with the classicalbiginelli reaction conditions, this method has the adv...

Journal: :journal of the iranian chemical research 0
nader noroozi pesyan department of chemistry, faculty of science, urmia university, urmia, iran abdul hossein abdul hossein dabbagh college of chemistry, isfahan university of technology, isfahan, iran

oxidation of some benzoins to benziles is reported by using p-toluenesulfonic acid as aselective oxidation catalyst under solvent-free condition in high yield. the adjacent carbonylgroup is necessary for the oxidation of hydroxyl group in these compounds. the reaction iscarried out in a sand-bath at 100 °c with minimum by-products.

Journal: :iranian chemical communication 0
rahimeh hajinasiri department of chemistry, islamic azad university, qaemshahr branch, p.o. box 163, qaemshahr, iran sanaz baravardeh department of chemistry, qaemshahr branch, islamic azad university, p.o. box 163, qaemshahr, iran sobhan rezayati department of chemistry, payame noor university, po box 19395-4697, tehran, iran

derivatives of thiazolidinone ring systems are known to act as anti-hiv infections , analgesic, anti-bacterial, anti-convulsant, anti parasitic, potential anti-inflammatory and herbicidal agents. due biological activities of thiazolidinones ring, several methods for their synthesis have been illustrated in literature. imidazolidine-2-thiones were synthesized by the oxidative cyclization of 1-be...

Journal: :journal of particle science and technology 0
zinat gordi department of chemistry, payame noor university, tehran, iran. mohammad vazan department of chemistry, payame noor university, tehran, iran.

a series of tri- and tetra- substituted imidazoles were synthesized from benzyl, aldehyde and ammonium acetate in the presence of zeolite as an ecofriendly reusable catalyst under microwave irradiation in the absence of solvent. the yields are high to excellent and the use of microwave irradiation reduces reaction times to few minute.

Journal: :ChemSusChem 2016
Li Shuai Jeremy Luterbacher

Transforming lignocellulosic biomass into fuels and chemicals has been intensely studied in recent years. A large amount of work has been dedicated to finding suitable solvent systems, which can improve the transformation of biomass into value-added chemicals. These efforts have been undertaken based on numerous research results that have shown that organic solvents can improve both conversion ...

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