Search results for " solution"
showing 10 items of 3084 documents
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.
ChemInform Abstract: Proton Coordination by Polyamine Compounds in Aqueous Solution
2010
Abstract The present article is concerned with proton transfer reactions in aqueous solution of open-chain, macrocyclic and macropolycyclic or cage compounds having nitrogen atoms as protonation sites in the molecular framework, although several compounds with additional different donors will be considered. The main purpose of this review is to collect some significant examples of proton transfer processes in order to show how the electronic properties and molecular topology of polyamines affect the thermodynamic parameters of their protonation equilibria.
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…
ChemInform Abstract: Synthesis of 3-Substituted Isoindolin-1-ones via a Tandem Desilylation, Cross-Coupling, Hydroamidation Sequence under Aqueous Ph…
2016
A simple and expedient method for the synthesis of 3-methylene-isoindolin-1-ones 4 under aqueous phase-transfer conditions has been developed. Starting from 2-iodobenzamides 1 and (silyl)alkynes, the products are obtained in high yields and short reaction times (30 min) with the use of inexpensive CuCl/PPh3 catalyst system in the presence of n-Bu4NBr (TBAB) as a phase-transfer agent. Terminal alkynes are conveniently “unmasked” upon in situ desilylation under the reaction conditions. Alkynes possessing heterocyclic moieties were also found as amenable substrates. Furthermore, a one-pot process starting from 2-iodobenzamides 1, aryl halides (bromides or iodides) and trimethylsilylacetylene (…
Separation of Enantiomers in a Monolayer of Racemic 3-Hexadecyl-oxy-propane-1,2-diol
1993
Monolayers of a racemic mixture and of the pure S enantiomer of 3-hexadecyloxy-propane-1,2-diol have been characterized by thermodynamic measurements at the air/water interface as well as by fluorescence microscopy. The critical temperatire T c , the limiting molecular area at high pressure and the pressure π c corresponding to the observed main phase transition, derived from the isotherms, slightly depend on chiral purity
Photocatalytic oxidation of acetonitrile in aqueous suspension of titanium dioxide irradiated by sunlight
2004
The photocatalytic oxidation of acetonitrile (CH3CN) was carried out in aqueous suspensions of polycrystalline TiO2 P25 Degussa irradiated by sunlight. A plug flow photoreactor in a total recycle loop was used for carrying out reactivity experiments in which the concentrations of acetonitrile, of its intermediate oxidation products and of not-purgeable organic carbon (NPOC) were monitored. The influence of the presence of strong oxidant species (H2O2, S2O82−, ClO−) on the process rate was studied. The dependence of acetonitrile photo-oxidation rate on the substrate concentration and on the catalyst amount was also investigated. The photodegradation rate of substrate and NPOC followed first …
The orientational glass state of argon:Nitrogen and cyanide mixed crystals
1990
Abstract Solid solutions of Ar:N 2 and ( KBr ) 1− x ( KCN ) x mixed crystals show a so-called orientational glass state where the orientations of the aspherical species, N 2 respectively CN - , are frozen in random patterns. The main experimental characteristics of this state and the pertinent theoretical concepts are discussed.
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.
Giant Crown-Shaped Polytungstate Formed by Self-Assembly of CeIII-Stabilized Dilacunary Keggin Fragments
2010
Single crystals of Na40K6[Ni(H2O)6]3 [K@K7Ce24Ge12W120O456 (OH)12(H2O)64]· 178H2O are synthesized by addition of KCl to a NaOAc/AcOH buffer solution containing Ce(NO3)3, GeO2, Na2WO4, and NiCl2 followed by slow evaporation at room temperature (24% yield).
Conformational study of methyl esters of some aliphaticerythro- andthreo-dichlorocarboxylic acids
1984
The average conformations of methyl esters of some aliphatic erythro- and threo-dichlorocarboxylic acids in dilute carbon tetrachloride solutions have been determined from the vicinal proton–proton coupling constants and 1H NMR shifts. The 13C shift differences between the erythro and threo forms are compared and discussed with regard to the differences in the average conformations.