نتایج جستجو برای: basicity

تعداد نتایج: 1286  

2016
Hisao Kiuchi Riku Shibuya Takahiro Kondo Junji Nakamura Hideharu Niwa Jun Miyawaki Maki Kawai Masaharu Oshima Yoshihisa Harada

The characteristics of CO2 adsorption sites on a nitrogen-doped graphite model system (N-HOPG) were investigated by X-ray photoelectron and absorption spectroscopy and infrared reflection absorption spectroscopy. Adsorbed CO2 was observed lying flat on N-HOPG, stabilized by a charge transfer from the substrate. This demonstrated that Lewis base sites were formed by the incorporation of nitrogen...

Journal: :Journal of the American Society for Mass Spectrometry 2012
Yi He Matthew A Lauber James P Reilly

It has previously been shown that when cross-linking reagent diethyl suberthioimidate (DEST) reacts with primary amines of proteins to yield amidinated residues, the primary amines retain their high basicity, and cross-linked species can be enriched by strong cation exchange. It is now demonstrated that collisional activation of singly-charged DEST cross-linked peptide ions leads to preferentia...

2003
Hari Nair Vicki H. Wysocki

The question of site of protonation in peptides that do not contain basic residues is addressed. The additional basicity of the peptide conferred by the amino terminus is removed by N-acetylation. Comparison of the surface-induced dissociation energy requirements for the fragmentation of the peptides with and without the N-terminal amine indicates that the N-terminal amine sequesters the proton...

Journal: :Chemical communications 2012
Hugo Cruz Markus Fanselow John D Holbrey Kenneth R Seddon

Using in situ viscosity measurement, the rate of cellulose dissolution in a number of ionic liquids has been determined allowing their performance as solvents to be quantitatively assessed. 1-Butyl-3-methylimidazolium ethanoate was shown to dissolve cellulose faster than analogous ionic liquids with chloride or dimethylphosphate anions. Analysis of the data highlights the influence of both anio...

2015
Agnieszka Kudelko Karolina Jasiak Krzysztof Ejsmont

ABSTRACT A series of novel 5-substituted 2-[2-(pyridyl)ethenyl]-1,3,4-oxadiazoles were efficiently synthesized by cyclocondensation of the appropriate 3-(pyridyl)acrylohydrazides with triethyl orthoesters in the presence of glacial acetic acid. The products were identified by means of spectroscopic methods and their pKA ionization constants were determined. The influence of substituents on the ...

Journal: :Physical chemistry chemical physics : PCCP 2013
Hirofumi Sato

This perspective highlights recent developments in the field of statistical mechanics for molecular liquids, i.e. the integral equation (IE) theory, especially focusing on hybrid approaches incorporating quantum chemistry and IE theory. The electronic structure of solvated molecules is characterized, followed by recent developments and applications. The latter includes for some specific systems...

Journal: :The Journal of organic chemistry 2009
Jianjun Zhang Cheng-Wei Tom Chang

A one-pot three-component [2+3] cycloaddition for the synthesis of 1-alkyl 1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione and 2-alkyl 2H-naphtho[2,3-d][1,2,3]triazole-4,9-dione has been developed. By taking the advantage of difference in basicity, both products can be obtained in good purity. The unique heterocyclic scaffolds of these two products could exert interesting chemical and biological pro...

Journal: :Organic & biomolecular chemistry 2008
Daniel M D'Souza Wei-Wei Liao Frank Rominger Thomas J J Müller

Microwave-assisted unimolecular isomerization-Claisen domino reactions of 1,3-di(hetero)aryl propargyl trityl ethers lead, depending on the basicity of the amine, either to the formation of tricyclo[3.2.1.0(2,7)]oct-3-enes (with triethylamine) or to indanes (with DBU). Based upon product analyses and computations, this base dependent dichotomy can be rationalized as a sequel of pericyclic react...

2005
A. Mohammad S. Hina

Thin-layer chromatography of nineteen amines has been performed on silica gel layers with a water-in-oil microemulsion (sodium dodecyl sulphate + water + heptane + n-pentanol, 8.0 g + 8.0 mL + 160.0 mL + 25.0 mL) as mobile phase. The effect of the basicity of the amines on their RF values was examined. The proposed thin layer chromatographic method was used to separate isomers of nitroaniline f...

Journal: :Isij International 2023

Developing the innovative technology for efficient utilization of high-phosphate iron ore was inevitable choice resource strategy. In this paper, exploring a new method gasification removal phosphorus by sintering based on biomass. Combined with theoretical analysis and experimental research, effects different conditions (biochar type, addition proportion, basicity) reduction behavior were stud...

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