Search results for "AROMA"
showing 10 items of 1006 documents
Mononuclear and tetranuclear Fe(III) complexes with two different types of N, O donor Schiff base ligands
2013
Abstract A mononuclear Fe(III) complex of a tetradentate N 2 O 2 donor Schiff base ligand derived from 3-ethoxysalicaldehyde and ethylenediamine has been reported. In addition two tetranuclear Fe(III) complexes with discrete Fe 4 III (μ 4 -O) cores have been synthesized and characterized using two Schiff base ligands (H 2 L 1–2 ) derived from two different aromatic acid hydrazides and diacetyl monoxime. The mononuclear Fe(III) and one of the tetranuclear Fe(III) complexes have been structurally characterized by single-crystal X-ray crystallography. The mononuclear complex has a highly distorted octahedral geometry. The tetranuclear Fe(III) complexes are found to be rare examples with discre…
Fluorogenic detection of Tetryl and TNT explosives using nanoscopic-capped mesoporous hybrid materials
2013
[EN] A hybrid capped mesoporous material, which was selectively opened in the presence of Tetryl and TNT, has been synthesised and used for the fluorogenic recognition of these nitroaromatic explosives.
Efficient ultraviolet-light energy dissipation by an aromatic ketone.
2010
Experimental evidence on the efficiency of 2,2'4,4'-tetramethoxybenzil for UV-light energy dissipation is provided. This non-phenolic aromatic ketone has a low energy triplet which quickly decays to the ketone ground state, thus avoiding the generation of undesirable reactive species. El Moncef, Abdelkarim, elmonab@alumni.uv.es ; Cuquerella Alabort, Maria Consuelo, Chelo.Cuquerella@uv.es ; Zaballos Garcia, Elena, Elena.Zaballos@uv.es ; Ramirez de Arellano Sanchez, Maria del Carmen, Carmen.Ramirezdearellano@uv.es ; Stiriba, Salah Eddine, Salah.Stiriba@uv.es ; Perez Prieto, Julia, Julia.Perez@uv.es
New Fluorescent Heterocyclic Compounds Derived From 3-Cyanobenzanthrone
2021
The four-cyclic condensed aromatic ketone 7H-benz[de]anthracene-7-one and its derivatives belong to the class of important anthraquinoid dyes, including laser and luminescent dyes. Current work is ...
Chemical and Microbiological Characterization for PDO Labelling of Typical East Piedmont (Italy) Salami
2015
This study is focused on the characterisation of typical salami produced in Alessandria province (North West of Italy). Seventeen small or medium salami producers from this area were involved in the study and provided the samples investigated. The aim is double and consists in obtaining a screening of the characteristics of different products and following their evolution along ripening. The study involved five types of typical salami that were characterised for aroma components and nutritional features. This approach could provide a basis for a possible PDO or PGI label request. Principal Component Analysis and cluster analysis were used as multivariate statistical tools for data treatment…
Aryl azides formation under mild conditions: a kinetic study in some ionic liquid solutions.
2009
The kinetics of nucleophilic aromatic substitution of three nitrothiophene derivatives in different [1-butyl-3-methylimidazolium][N(3)]/ionic liquid binary mixtures was studied spectrophotometrically at 298 K. Ionic liquids differing for cation structure (imidazolium or pyrrolidinium) and for size, shape, and coordination ability of the anion ([BF(4)(-)], [PF(6)(-)], [SbF(6)(-)], and [NTf(2)(-)]) were used. Furthermore, in order to have a comparison with conventional organic solvents, the target reaction was also carried out in DMF solution at increasing concentration of NaN(3) or [bmim][N(3)]. Data collected show that the reaction occurs faster in DMF than in ionic liquid solution. Further…
Ionic liquids/[bmim][N3] mixtures: promising media for the synthesis of aryl azides by SNAr
2008
The nucleophilic aromatic substitution of some activated aryl or heteroaryl halides has been performed in ionic liquid solution, using the 1-butyl-3-methylimidazolium azide as a nucleophile. The reaction course was studied varying the structures of both substrates and ionic liquids. In particular, in the latter case, the reaction of 2-bromo-5-nitrothiophene was carried out in five different ionic liquids ([bmim][BF 4], [bmim][PF 6], [bmim][NTf 2], [bm 2im][NTf 2], and [bmpyrr][NTf 2]). Finally, for all the substrates considered, a comparison with data obtained in MeOH solution in the presence of NaN 3 was also performed. Data collected indicate that in some cases it is possible to obtain ar…
Urban organic aerosol composition in eastern China differs from north to south:Molecular insight from a liquid chromatography-mass spectrometry (Orbi…
2021
Air pollution by particulate matter in China affects human health, the ecosystem and the climate. However, the chemical composition of particulate aerosol, especially of the organic fraction, is still not well understood. In this study, particulate aerosol samples with a diameter of ≤2.5 µm (PM2.5) were collected in January 2014 in three cities located in northeast, east and southeast China, namely Changchun, Shanghai and Guangzhou. Organic aerosol (OA) in the PM2.5 samples was analyzed by an ultrahigh-performance liquid chromatograph (UHPLC) coupled to a high-resolution Orbitrap mass spectrometer in both negative mode (ESI-) and positive mode electrospray ionization (ESI+). After non-targe…
Determination of alkylamines in atmospheric aerosol particles: a comparison of gas chromatography–mass spectrometry and ion chromatography approaches
2014
Abstract. In recent years low molecular weight alkylamines have been recognized to play an important role in particle formation and growth in the lower atmosphere. However, major uncertainties are associated with their atmospheric processes, sources and sinks, mostly due to the lack of ambient measurements and the difficulties in accurate quantification of alkylamines at trace level. In this study, we present the evaluation and optimization of two analytical approaches, i.e., gas chromatography–mass spectrometry (GC-MS) and ion chromatography (IC), for the determination of alkylamines in aerosol particles. Alkylamines were converted to carbamates through derivatization with isobutyl chlorof…
Organosulfates in atmospheric aerosol: synthesis and quantitative analysis of pm<sub>2.5</sub> from xi'an, northwestern c…
2018
Abstract. The sources, formation mechanism and amount of organosulfates (OS) in atmospheric aerosol are not yet well understood, partly due to the lack of authentic standards for quantification. In this study, we report an improved robust procedure for the synthesis of organosulfates with different functional groups. Nine authentic organosulfate standards were synthesized and four standards (benzyl sulfate, phenyl sulfate, glycolic acid sulfate, and hydroxyacetone sulfate) were used to quantify their ambient concentrations. The authentic standards and ambient aerosol samples were analyzed using an optimized ultra performance liquid chromatography–electrospray ionization-tandem mass spectrom…