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Heavy Water (heavy + water)

Distribution by Scientific Domains

Chemistry	60%

Selected Abstracts

Electrical Discharges in Mixtures of Light and Heavy Water

PLASMA PROCESSES AND POLYMERS, Issue 1 2008
Selma Mededovic
Abstract Pulsed electrical discharges in pure solutions and mixtures of light and heavy water are examined. The concentration of H2O2 formed by electrical discharge in 100% H2O was found to be 1.4 times smaller than that of D2O2 produced by electrical discharge in 100% D2O. This difference in peroxide formation was due to the high reactivity of OH radicals with other species in the plasma channel, thereby reducing OH recombination to form H2O2, while the lower reactivity of OD radicals with other species allowed more OD recombination reactions to form D2O2. A new method based on Raman spectroscopy was also developed to quantify H2O2, D2O2, and HDO2 in mixtures containing all three species. [source]

Anomalous conformational properties of PEO in H2O and D2O by SANS, PCS and Raman scattering

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3-1 2000
C. Branca
PEO solutions in water and heavy water have been investigated using SANS, PCS and Raman spectroscopy. The employement of these techniques allows to carry out a comparison between the diffusive properties of PEO/H2O and PEO/D2O systems, in order to study the coil conformation dependence on temperature and concentration. The data reveal the different conformational properties of PEO in the two solvents which have been attributed to a different solvent quality of H2O and D2O. These results provide evidence to the fact that the properties of macromolecules, even of simple structure, can be influenced by the isotopic composition of the solvent. [source]

Enzymatic synthesis of l-tryptophan and 5prime-hydroxy-l-tryptophan labeled with deuterium and tritium at the alpha-carbon position

JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 8 2003
E. Boroda
Abstract The enzymatic synthesis of l-tryptophan and its derivative 5,-hydroxy-l-tryptophan labeled with deuterium and tritium at the ,-carbon position is reported. The mixture containing S -methyl-l-cysteine, indole or 5-hydroxyindole dissolved in deuteriated or tritiated water has been converted to [2- 2H]-l-tryptophan, [2- 3H]-l-tryptophan, 5,-hydroxy-[2- 2H]-l-tryptophan, and 5,-hydroxy-[2- 3H]-l-tryptophan, respectively, in a one-pot reaction using the enzyme tryptophanase. The same reaction carried out in heavy water with THO added yielded either doubly labeled [2- 2H/3H]-l-tryptophan or 5,-hydroxy-[2- 2H/3H]-l-tryptophan. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Electrical Discharges in Mixtures of Light and Heavy Water

Micro-Hydration of the MgNO3+ Cation in the Gas Phase

CHEMPHYSCHEM, Issue 11 2007
Barbara Jagoda-Cwiklik Dr.
Abstract Coordination complexes of the magnesium nitrate cation with water [MgNO3(H2O)n]+ up to n=7 are investigated by experiment and theory. The fragmentation patterns of [MgNO3(H2O)n]+ clusters generated via electrospray ionization indicate a considerable change in stability between n=3 and 4. Further, ion,molecule reactions of mass-selected [MgNO3(H2O)n]+ cations with D2O reveal the occurrence of consecutive replacement of water ligands by heavy water, and in this respect the complexes with n=4 and 5 are somewhat more reactive than their smaller homologs with n=1,3 as well as the larger clusters with n=6 and 7. For the latter two ions, the theory suggests the existence of isomers, such as complexes with monodentate nitrato ligands as well as solvent-separated ion pairs with a common solvation shell. The reactions observed and the ion thermochemistry are discussed in the context of ab initio calculations, which also reveal the structures of the various hydrated cation complexes. [source]