Search results for "bromine"
showing 10 items of 102 documents
Kinetik der Bromierung von Phenolen und phenolischen Mehrkernverbindungen, 1. Mechanismus und meßmethode
1975
Die Bromierung von 2-(2-Hydroxy-5-methylbenzyl)-4,6-dimethylphenol (1) und 2-[2-Hydroxy-3-(2-hydroxy-5-methylbenzyl)-5-methylbenzyl]-4,6-dimethylphenol (2a) wurde in Eisessig bei 22°C untersucht. Die Reaktion last sich fur [Br2]0 = 1,4·10−3 bis 6,0·10−3 mol dm + und Konzentrationen der phenolischen Verbindungen [P]0 zwischen 1,1·10−3 und 5,5·10−3mol dm−3 durch das folgende Geschwindigkeitsgesetz beschreiben: Wahrend die gebildete Bromverbindung keinen Einflus auf die Reaktionsgeschwindigkeit hat, verlangsamt der entstehende Bromwasserstoff die Reaktion. Die Bromierung ist trotzdem zur Bestimmung der Reaktionsfahigkeit von Phenolen und phenolischen Mehrkernverbindungen gut geeignet, da die R…
On-line in-tube solid phase microextraction coupled to capillary liquid chromatography-diode array detection for the analysis of caffeine and its met…
2019
Abstract In-tube solid phase microextraction (IT-SPME) coupled on-line to capillary liquid chromatography with diode array detection provides a simple and fast analytical methodology for the simultaneous quantitation of caffeine and its three primary metabolites (theobromine, paraxanthine and theophylline) in micro samples of serum, saliva and urine matrices. The sample amount required for one analysis was only 2.5 μL of saliva, 6.25 μL of serum or 40 μL of urine, a requirement for its implementation in a hospital laboratory for preterm newborns, where sample availability is a major problem. In standard conditions, 25 μL of diluted saliva or serum (or 100 μL of urine) were processed by IT-S…
Process for the production of bromine
2016
A process for the preparation of molecular bromine, by means of advanced oxidation processes or their combination is disclosed
Greeen Synthesis of Bromine through photocatalysis and ozonation
2017
Greeen Synthesis of Bromine through photocatalysis and ozonation
Br2 production from photocatalysis and/or ozonation of bromide containing aqueous solutions: kinetics and mechanisms
2018
Br2 production from photocatalysis and/or ozonation of bromide containing aqueous solutions: kinetics and mechanisms
CCDC 1012799: Experimental Crystal Structure Determination
2015
Related Article: Laura Koskinen, Sirpa Jääskeläinen, Pipsa Hirva, Matti Haukka|2015|Cryst.Growth Des.|15|1160|doi:10.1021/cg501482u
Rapid chemical evolution of tropospheric volcanic emissions from Redoubt Volcano, Alaska, based on observations of ozone and halogen-containing gases
2013
Abstract We report results from an observational and modeling study of reactive chemistry in the tropospheric plume emitted by Redoubt Volcano, Alaska. Our measurements include the first observations of Br and I degassing from an Alaskan volcano, the first study of O 3 evolution in a volcanic plume, as well as the first detection of BrO in the plume of a passively degassing Alaskan volcano. This study also represents the first detailed spatially-resolved comparison of measured and modeled O 3 depletion in a volcanic plume. The composition of the plume was measured on June 20, 2010 using base-treated filter packs (for F, Cl, Br, I, and S) at the crater rim and by an instrumented fixed-wing a…
X-ray powder diffraction study of the stability of solid solutions in LaO(Cl1−xBrx)
1997
Abstract The formation of solid solutions in the LaO(Cl 1− x Br x ) series was studied by X-ray powder diffraction (XPD), Rietveld profile refinement and bond valence calculations. The LaO(Cl 1− x Br x ) (0 ≤ x ≤ 1, step 0.2, and x = 0.5) powder samples were prepared by the solid state reaction between La 2 O 3 and a mixture of ammonium chloride and bromide. The X-ray powder diffraction patterns were collected at room temperature between 5 and 125° in 2Θ using Cu K α 1 radiation (λ = 1.5406 A). The XPD data between 20 and 90° were analyzed with the DBWS-9006PC Rietveld profile refinement program. All the LaO(Cl 1− x Br x ) phases studied crystallize in the tetragonal PbFCl-type structure wi…
Global sea-to-air flux climatology for bromoform, dibromomethane and methyl iodide
2013
Volatile halogenated organic compounds containing bromine and iodine, which are naturally produced in the ocean, are involved in ozone depletion in both the troposphere and stratosphere. Three prominent compounds transporting large amounts of marine halogens into the atmosphere are bromoform (CHBr3), dibromomethane (CH2Br2) and methyl iodide (CH3I). The input of marine halogens to the stratosphere has been estimated from observations and modelling studies using low-resolution oceanic emission scenarios derived from top-down approaches. In order to improve emission inventory estimates, we calculate data-based high resolution global sea-to-air flux estimates of these compounds from surface ob…
The role of melt composition on aqueous fluid vs. silicate melt partitioning of bromine in magmas
2018
International audience; Volcanogenic halogens, in particular bromine, potentially play an important role in the ozone depletion of the atmosphere. Understanding bromine behaviour in magmas is therefore crucial to properly evaluate the contribution of volcanic eruptions to atmospheric chemistry and their environmental impact. To date, bromine partitioning between silicate melts and the gas phase is very poorly constrained, with the only relevant experimental studies limited to investigation of synthetic melt with silicic compositions. In this study, fluid/melt partitioning experiments were performed using natural silicate glasses with mafic, intermediate and silicic compositions. For each co…