نتایج جستجو برای: acidic solvents

تعداد نتایج: 78820  

Ali Shamel Farrokh Gharib

The oxidation of n-pentanol by tetramethylammonium fluorochromate in acidic solution wasstudied using spectrophotometric technique. The reaction was arranged to be under pseudo firstorderconditions respect to the oxidant. A Michaelis-Menten type kinetic was observed respect tothe substrate. The reaction is catalyzed by hydrogen ions. Dependences of the reaction rates ontemperature and different...

Journal: :Chemical communications 2014
Gour Chand Daskhan Narayanaswamy Jayaraman

Synthesis of amphiphilic, cyclic di- and tetrasaccharides, which incorporate a methylene moiety at the inter-glycosidic bond, is reported. The amphiphilic properties of the new cyclic tetrasaccharide host were identified through assessing the solubilities of guests in aqueous and in organic solvents. The glycosidic bond stability of the cyclic tetrasaccharide under aqueous acidic condition was ...

2017
Pedro H. F. Stroppa Nícolas Glanzmann Lucas M. Duarte Renata T. Sato Marcone A. L. de Oliveira Adilson D. da Silva

In this work, we describe the synthesis of a novel 9-aminoacridine derivative that presents surprisingly different colors when exposed to neutral, acidic or basic mediums with potential application as pH indicator in organic solvents. Furthermore, pKa and molar absorptivity values were determined and theoretical studies supported by density functional theory (DFT) calculations were performed to...

Journal: :Physical chemistry chemical physics : PCCP 2011
Mathieu Salanne Christian Simon Paul A Madden

In an inorganic material, a measure of the Lewis basicity of a solvent is commonly provided by the optical basicity, i.e. the ability of the solvent molecules to donate their electrons to an acidic species. This quantity is known to vary with the polarizability of the Lewis base. In protic solvents, the Lewis definition of basicity is barely used; it is replaced by the more purpose-built Brønst...

Journal: :Nanoscale 2015
Alexey Klechikov Junchun Yu Diana Thomas Tiva Sharifi Alexandr V Talyzin

The change of distance between individual graphene oxide sheets due to swelling is the key parameter to explain and predict permeation of multilayered graphene oxide (GO) membranes by various solvents and solutions. In situ synchrotron X-ray diffraction study shows that swelling properties of GO membranes are distinctly different compared to precursor graphite oxide powder samples. Intercalatio...

Journal: :Indian journal of experimental biology 2007
D Chakraborty S M Mandal J Chakraborty P K Bhattacharyaa A Bandyopadhyay A Mitra K Gupta

Phenolic extract of leaves of Basilicum polystachyon (L) Moench was tested for in vitro antimicrobial activity against five bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Micrococcus leuteus) and three fungi (Fusarium oxysporum, Aspergillus niger, Helminthosporium oryzae). Efficacy of organic solvents, methanol and ethanol, as agents for extraction...

2013
Uwe R. Aulwurm Falk Knoch Horst Kisch

Refluxing a slightly acidic /?-BuOH solution of RhCKPPh,), and 2-chloro-, 2,4-dichloro-, or 2,4,6-trichloroazobenzene affords cyclometalated complexes (1) via loss of one phosphine ligand and oxidative addition of the ortho -C-Cl bond. X-ray structural analysis indicates a frcws-position of the two triphenylphosphine ligands. The reaction proceeds only in polar solvents like alcohols or dimethy...

2012
Senthil Narayanaperumal Rodrigo César da Silva Julia L. Monteiro Arlene G. Corrêa Márcio W. Paixão

H and C nuclear magnetic resonance (NMR) spectra were recorded at 400 MHz on a Bruker ARX-400 NMR spectrometer (Germany) with tetramethylsilane as internal standard. Column chromatography was performed using Merck (Germany) silica gel (230-400 mesh). Thin layer chromatography (TLC) was performed using Merck silica gel GF254, 0.25 mm thickness. For visualization, TLC plates were placed under aci...

Journal: :Molecules 2015
Yonghong Zhang Bin Wang Xiaomei Zhang Jianbin Huang Chenjiang Liu

We report here an efficient and green method for Biginelli condensation reaction of aldehydes, β-ketoesters and urea or thiourea catalyzed by Brønsted acidic ionic liquid [Btto][p-TSA] under solvent-free conditions. Compared to the classical Biginelli reaction conditions, the present method has the advantages of giving good yields, short reaction times, near room temperature conditions and the ...

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