Search results for "Sodium"

Electrochemical reduction of the nitrite to ammonium ions in presence of [MoO2(O2CC(S)C6H5)2]2−

1995

Abstract Ammonia is formed during potentiostatic reduction of sodium nitrite solutions on the nafion-complex-coated electrode. When (NH4)2[MoO2(O2CC(S)(C6H5)2)2] is present in NaNO2 solutions a polarographic wave is associated to electrocatalytic reduction of nitrite ion. The wave height varies linearly on the concentration of nitrite ion, allowing a procedure for analysing this ion. This electrochemical behaviour distinguishes the nitrite from the nitrate ions. The Mo(VI), Mo(V), and Mo(IV) are involved in catalytic redox processes determining formation of NH4+ from nitrite ions.

Studien zum Vorgang der Wasserstoffübertragung 36 [1] Einfluß von Art und Struktur einiger Leitsalze auf die elektrochemische Spaltung von Diarylsulf…

1975

Tensammetrische Messungen bestatigen, das Tetraalkylammoniumsalze in Methanol mit steigender Kettenlange der Alkylreste und wachsender Konzentration zunehmend starker an der Quecksilberoberflache adsorbiert werden. Polarographie und Zyklovoltammetrie der Diarylsulfone 1–8 in Methanol lassen folgende Schlusse zu: 1 Unabhangig von der Alkylkettenlange der Tetraalkylammoniumsalze werden die Diarylsulfone 1–6 nach einem ECE-Mechanismus gespalten. Bei Verwendung von Alkalileitsalzen sind die genannten Sulfone polarographisch inaktiv. 2 Beim 4-Cyano-diphenylsulfon wird mit Tetramethylammoniumchlorid zyklovoltammetrisch keine Reversibilitat des ersten Elektronen ubergangs beobachtet, wohl aber mit…

2009

Abstract. Understanding the importance of the different oxidation pathways of sulfur dioxide (SO2) to sulfate is crucial for an interpretation of the climate effects of sulfate aerosols. Sulfur isotope analysis of atmospheric aerosol is a well established tool for identifying sources of sulfur in the atmosphere and assessment of anthropogenic influence. The power of this tool is enhanced by a new ion microprobe technique that permits isotope analysis of individual aerosol particles as small as 0.5 μm diameter. With this new single particle technique, different types of primary and secondary sulfates are first identified based on their chemical composition, and then their individual isotopic…

Preparation of N,O-Aminals as Synthetic Equivalents of H2C=NAr and (H2C=NHAr)+ Ions: Neutral and Acid-promoted Transformations

1988

A general method for the synthesis of N,O-aminals derived from primary aromatic amines is described. The reactivity of these compounds under neutral and acidic conditions has been studied and the title compounds can be envisaged as general purpose H2C=NAr or (H2C=NHAr)+ equivalents. N,O-Aminals have been converted into perhydrotriazines by moderate heating and into bis(4-aminoaryl) methane derivatives or N-benzylarylamines, respectively when heated in acidic media with pH control. Reduction of N, O-acetals with sodium cyanoborohydride has revealed that the C-O bond is broken exclusively in acidic media.

Stereoselective synthesis of glycosides and anomeric azides of glucosamine

1992

The β-azide of O-acetyl protected N-acetyl glucosamine is efficiently accessible via a phasetransfer-catalyzed reaction of the corresponding glycosyl chloride with sodium azide. The azido group revealed to be a useful anomeric protection for modifications of the protecting group pattern of the glucosamine unit. Exchange of the O-acyl groups by 4-methoxybenzylidene and 4-methoxybenzyl (Mpm) protection delivered regioselectively blocked glucosaminyl azide derivatives. In contrast, the N-phthaloyl protected glucosaminyl azide was obtained quantitatively from the corresponding glycosyl fluoride via a boron trifluoride-promoted reaction with trimethylsilyl azide. N-Phthaloyl glucosaminyl fluorid…

ChemInform Abstract: Stereoselective Synthesis of Glycosides and Anomeric Azides of Glucosamine.

2010

The β-azide of O-acetyl protected N-acetyl glucosamine is efficiently accessible via a phasetransfer-catalyzed reaction of the corresponding glycosyl chloride with sodium azide. The azido group revealed to be a useful anomeric protection for modifications of the protecting group pattern of the glucosamine unit. Exchange of the O-acyl groups by 4-methoxybenzylidene and 4-methoxybenzyl (Mpm) protection delivered regioselectively blocked glucosaminyl azide derivatives. In contrast, the N-phthaloyl protected glucosaminyl azide was obtained quantitatively from the corresponding glycosyl fluoride via a boron trifluoride-promoted reaction with trimethylsilyl azide. N-Phthaloyl glucosaminyl fluorid…

INTERACTION BETWEEN SODIUM NITRITE AND BETA ADRENERGIC BLOCKERS ON ISOLATED RAT AORTA

1978

A Mössbauer study of the crystalline structure of the passive film formed on iron in aqueous sulfate solution containing sulfite in low concentration

1993

Electrochemically induced passivation of evaporated, enriched 57Fe in 0.5 mol dm−3 Na2SO4 + 0.001 mol dm−3 NaHSO3 aqueous solution (pH 6.5) was followed by conversion electron Mossbauer spectroscopy. The transformation of amorphous iron oxide or hydroxide into crystalline γ-FeOOH could be observed with the increase of the polarization time. The comparison of the original quantity of evaporated, enriched 57Fe layer on the surface of the samples with the dissolved iron, measured in the solutions after the polarization, proved the existence of pitting corrosion at this pH.

Evidence for the formation of sodium hassate(VIII)

2004

SummaryHassium, element 108, was produced in the fusion reaction between26Mg and248Cm. The hassium recoils were oxidizedin-situto a highly volatile oxide, presumably HsO4, and were transported in a mixture of He and O2to a deposition and detection system. The latter consisted of 16 silicon PIN-photodiodes facing a layer of NaOH, which served, in the presence of a certain partial pressure of water in the transport gas, as reactive surface for the deposition of the volatile tetroxides. Six correlated α-decay chains of Hs were detected in the first 5 detectors centred around detection position 3. In analogy to OsO4, which forms Na2[OsO4(OH)2], an osmate(VIII), with aqueous NaOH, HsO4presumably…

Isobaric Vapor−Liquid Equilibrium for Ethanol + Water + Strontium Nitrate

1996

Isobaric vapor−liquid equilibrium for ethanol (1) + water (2) + potassium nitrate (3) at various concentrations of salt and with ethanol mole fractions from 0 to 0.642 has been measured at 100.0 kPa. The results were correlated by assuming that the salt was in ionic form and it was associated only with the water.