New sources of “active” halogen bis(dialkylamide)hydrogen dibromobromates, efficient reagents for destruction of ecotoxicants

Bis(dialkylamide)hydrogen dibromobromates were synthesized and their reactivity was investigated in decomposition of diethylphosphonic, diethylphosphoric, and 4-toluenesulfonic acids 4-nitrophenyl esters. The nucleophilic reactivity of a typical α-nucleophile, hypobromite ion, is independent of the source of the active bromine. The cetyltrimethylammonium dibromobromate is a unique reagent for destruction of ecotoxicants. In weakly alkaline media the half-life of 4-nitrophenyl diethylphosphonate did not exceed 6 s at [BrO^?] 0.02 mol l^?1, and the apparent reaction rate compared to water increased ～40-fold. The main factor governing the micellar effects of surfactants is concentrating the substrate in the micellar pseudophase.     

Intracavity laser polarization spectrometer for biomolecule traces

A polarization variant of an intracavity laser spectrometer based on the competition of beams in an argon ion laser, radiating a number of narrow lines in the 275 to 529 nm spectral range, is proposed and described for the spectral analysis of liquid samples, having broad absorption bands, mainly biomolecules in solutions. By careful optimization of the operating conditions, a procedure has been established that results in a minimal measurable absorbance decreased up to 10(-5) units of optical density. The examined spectrometer provides a wide dynamic range of analysis. A determination of trace contents of amino acids in methanol were carried out.     

Intracavity laser atomic absorption spectrometry with graphite furnace atomizer or pulsed laser sampler

An absorption intracavity laser spectrometer with two types of sample vaporization systems (graphite furnace electrothermal atomizer or laser sampler) is described that can be used for the determination of trace amounts of metals (Al, Cr, Fe and Mn) in liquid samples and at the surface of solid targets. The limits of detection for the elements tested are lower than those obtained by modern conventional spectrometers. The examined technique provides a wide dynamic range of linear standard calibration curves.     

Reaction of N,N-Dialkylcarboxamides with Halogens

N,N-Dialkylcarboxamides react with halogens in the absence of water to form complexes which are likely to have an ionic structure with the Hlg⁺ ion coordinated at the carbonyl oxygen atom. These products can be isolated as individual compounds. Complexes with bromine undergo further transformations to afford bis-dialkylamide hydrogen tribromide and the corresponding -bromo amide. When the reaction is carried out in the presence of water, the products are only bis-dialkylamide hydrogen tribromides; here, the N-alkyl groups act as a source of protons.     

Laser-induced modification of composite Cu-C nanosized particles synthesized using a pulsed electrical discharge in a liquid

Composite copper-containing carbon nanosized structures were synthesized in the plasma of a pulsed electrical discharge, initiated between two graphite electrodes in an aqueous copper chloride solution. We studied the effect of laser radiation on the morphology of the nanoparticles formed, whose properties we studied by optical absorption spectroscopy and transmission electron microscopy. We discuss the mechanisms for nanoparticle formation in a discharge submerged in a liquid, and the possibilities for laser-induced modification of the nanoparticles. We estimated the temperature of the nanoparticles when exposed to laser radiation pulses. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 372–378, May–June, 2008.