Search results for "Acetic Acid"

Selective oxidation of propane over alkali-doped Mo-V-Sb-O catalysts

2009

[EN] Alkali metal-doped MoVSbO catalysts have been prepared by impregnation of a MoVSbO-mixed oxide (prepared previously by a hydrothermal synthesis) and finally activated at 500 or 600 degrees C in N-2. The catalysts have been characterized and tested for the selective oxidation of propane and propylene. Alkali-doped catalysts improved in general the catalytic performance of MoVSbO, resulting more selective to acrylic acid and less selective to acetic acid than the corresponding alkali-free MoVSbO catalysts. However, the specific behaviour strongly depends on both the alkali metal added and/or the final activation temperature. At isoconversion conditions, catalysts activated at 600 degrees…

Evaluation of biosorbents for Cu removal from wastewater in the presence of EDTA

2007

BACKGROUND: This paper evaluates the use of several biosorbents for Cu removal from aqueous solutions in the absence and presence of ethylenediaminetetraacetic acid (EDTA). The objective was to determine the applicability of the sorption process after conventional physicochemical wastewater treatment, or as primary treatment, replacing the physicochemical process. RESULTS: Fixed-bed experiments were performed at Cu influent concentrations of 2 and 20 mg dm−3 and EDTA doses between 0 and 10 mg dm−3. At low Cu concentration without EDTA, Cu uptake capacity followed the order Posidonia oceanica > chitosan > chitin > Scharlau AC > Darco AC, with a maximum, at C/C0 = 0.2, of 23.2 mg g−1. In the …

High gas-phase mixing ratios of formic and acetic acid in the High Arctic

2018

Abstract. Formic and acetic acid are ubiquitous and abundant in the Earth's atmosphere and are important contributors to cloud water acidity, especially in remote regions. Their global sources are not well understood, as evidenced by the inability of models to reproduce the magnitude of measured mixing ratios, particularly at high northern latitudes. The scarcity of measurements at those latitudes is also a hindrance to understanding these acids and their sources. Here, we present ground-based gas-phase measurements of formic acid (FA) and acetic acid (AA) in the Canadian Arctic collected at 0.5 Hz with a high-resolution chemical ionization time-of-flight mass spectrometer using the iodide …

Clathrin-mediated constitutive endocytosis of PIN auxin efflux carriers in Arabidopsis.

2007

SummaryEndocytosis is an essential process by which eukaryotic cells internalize exogenous material or regulate signaling at the cell surface [1]. Different endocytic pathways are well established in yeast and animals; prominent among them is clathrin-dependent endocytosis [2, 3]. In plants, endocytosis is poorly defined, and no molecular mechanism for cargo internalization has been demonstrated so far [4, 5], although the internalization of receptor-ligand complexes at the plant plasma membrane has recently been shown [6]. Here we demonstrate by means of a green-to-red photoconvertible fluorescent reporter, EosFP [7], the constitutive endocytosis of PIN auxin efflux carriers [8] and their …

Nucleophilic substitutions on bromotriazolopyridines - an improved route to 2,6-disubstituted pyridines and to 1,3-disubstituted isoquinolines

1986

Abstract A regiospecific synthesis of 2,6-disubstituted pyridines and of 1,3-disubstituted isoquinolines is described.

Determination of biogenic amines in meat by combined ion-exchange capillary gas chromatography

1984

Abstract A procedure is described for the determination of putrescine, cadaverine and histamine in meat. Crude perchloric acid extracts were pre-separated on a weakly acidic cation exchanger and the amines quantified by capillary gas chromatography. The diamines were analysed as trifluoroacetyl derivatives and histamine was converted into N α -trifluoroacetyl-N τ -ethoxycarbonylhistamine. The accuracy of the determination of diamines was examined by a precipitation pre-separation method and by mass fragmentometric quantification. The proposed procedure allows the sensitive, sufficiently precise and highly specific determination of putrescine and cadaverine in meat.

Electrochemical processes in macro and microfluidic cells for the abatement of chloroacetic acid from water

2014

Evolution of microbiological and chemical parameters during red wine making with extended post-fermentation maceration.

2014

Abstract The aim of the present work was to investigate the microbiological, chemical, and sensory characteristics of red wine subjected to post-fermentation maceration that was extended to 90 days. For this purpose, the ‘Aglianico di Taurasi’ grape was used as a case study. The total yeast concentration increased until day 40 of maceration and decreased thereafter, whereas the concentration of lactic acid bacteria slightly increased. Dekkera/Brettanomyces spp. and acetic acid bacteria were not detected. The yeast community was composed of Saccharomyces cerevisiae, Zygosaccharomyces bisporus, Metschnikowia pulcherrima, Hanseniaspora guilliermondii, Hanseniaspora uvarum, Pichia guilliermondi…

Improving sensitivity in simultaneous determination of copper carboxylates by nonaqueous capillary electrophoresis

2005

Abstract A new method of nonaqueous capillary electrophoresis (NACE) with UV spectrophotometric detection was developed and optimized for the simultaneous determination of seven carboxylates (trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA), nitrilotriacetic acid (NTA), 1,3-diaminopropane-N,N,N′,N′-tetraacetic acid (PDTA) and triethylenetetraaminehexaacetic acid (TTHA)) as copper complexes. The method development was carried out by using a fused silica capillary. Background electrolyte (BGE) was optimized and the best separation a…

ChemInform Abstract: Experimental and Theoretical Studies on the Electronic Spectra of Indole-3-acetic Acid and Its Anionic and Protonated Species.

2010

Abstract The geometrical and electronic structure of indole-3-acetic acid (IAH) have been investigated using the MINDO/3 molecular orbital method, the geometries being optimized by Rinaldi's method. The UV spectrum of IAH has been recorded in different solvents. The corresponding spectra of IAH + 2 and IA − were also respectively obtained, from IAH in different H 2 SO 4 /water mixtures and NaOH solutions. The agreement of experimental spectra with the ones theoretically calculated by the CNDO/M-Cl method after optimization of the κ parameter, is discussed. The p K a values of IAH have also been determined from the IAH + 2 spectra and are compared with literature data.