Дейтерия оксид

Химические свойства

colourless liquid

Использование

Deuterium Oxide is used to prepare specifically labelled isotopologs of organic compounds.

Определение

deuterium oxide: Water in which hydrogen atoms, 1H,are replaced by the heavier isotopedeuterium, 2H (symbol D). It is acolourless liquid, which forms hexagonalcrystals on freezing. Its physicalproperties differ from those of ‘normal’water; r.d. 1.105; m.p. 3.8°C; b.p.101.4°C. Deuterium oxide, D₂O, occursto a small extent (about 0.003%by weight) in natural water, fromwhich it can be separated by fractionaldistillation or by electrolysis. Itis useful in the nuclear industry becauseof its ability to reduce the energiesof fast neutrons to thermalenergies and because its absorptioncross-section is lower than that of hydrogenand consequently it does notappreciably reduce the neutron flux.In the laboratory it is used for labellingother molecules for studies ofreaction mechanisms. Water alsocontains the compound HDO.

Общее описание

Deuterium oxide (D₂O) is a 100% isotopically enriched NMR (Nuclear Magnetic Resonance) solvent. It is widely employed in high resolution NMR studies. Various thermodynamic properties (such as intermolecular vibrational frequencies, energy of the hydrogen bond, free energy, enthalpy and entropy) of liquid deuterium oxide have been evaluated. Ionization constant for D₂O (in the range of 5-50°C), pK values (at 25°C) and enthalpy, entropy, heat capacity change (for the dissociation of D₂O) have been reported.

Методы очистки

Distil it from alkaline KMnO4 [de Giovanni & Zamenhof Biochem J 92 79 1963]. NOTE that D2O invariably contains tritiated water and will therefore be RADIOACTIVE; always check the radioactivity level of D2O in a scintillation counter before using.