Deuterium oxide properties

The slightly different physical properties of deuterium allow its concentration in ordinary hydrogen (or the concentration of a deuterium-containing compound in a hydrogen compound) to be determined. Exchange of deuterium and hydrogen occurs and can be used to elucidate the mechanism of reactions (i.e. the deuterium is a non-radioactive tracer). Methanol exchanges with deuterium oxide thus ... 

Surfactant mixtures were used as obtained and are listed with their properties in Table II. Sodium chloride and calcium chloride were Fisher reagent grade. Deuterium oxide was Aldrich Gold Label and had a surface tension of 70.4 mN/m at 23°C measured with a W iI heImy pi ate tens i ometer. 

Buncel and co-wortcers (48) also came to the conclusion that 2.4.6-trinitrotoluene has acid properties. They based it on their report of a ready exchange of ( Hjt protons of the compound in basic medium of deuterium oxide... 

TABLE 2-209 Thermodynamic Properties of Deuterium Oxide (Heavy Water)... 

One further interesting development took place in 1932, when Urey discovered isotopes of hydrogen. In these cases, the masses of the isotopes differ from each other by as much as 100% (Urey Grieff, 1935). The properties of these isotopes are definitely not the same. For example water (mostly protium oxide) has a boiling point of 100°C, whereas the value for deuterium oxide is 104°C. Strictly speaking, Fajans had been correct to doubt replaceability, but the problem is only significant in isotopes with very low masses, and Urey s discovery did not change the chemical definition of an element in any way. 

Lewis was also the first to produce a pure sample of deuterium oxide (heavy water) in 1933. By accelerating deuterons (deuterium nuclei) in Ernest 0. Lawrence s cyclotron, he was able to study many of the properties of atomic nuclei. 

The hydrogen atoms at position 2 of 2-unsubstituted dihydrothiazine oxides are expected to possess acidic properties. Thus, when treated with sodium deuterioxide in deuterium oxide, the compound 208b underwent deuterium exchange of the hydrogen atoms adjacent to the sulfinyl group ... 

However, all the free hydroxyl groups of cellulose are weakly ionizable, as is shown by the complete exchange of hydrogen for deuterium which takes place when it is immersed in deuterium oxide. The more acidic properties of the C2 hydroxyl group might be attributable to a permanent polarization of hydroxyl groups adjacent to a carbonyl or potential carbonyl group (see p. 293). 

Another measure of the asymmetric kinetic properties of the two bases in the alanine racemase mechanism is the qualitative behavior of the equilibrium overshoots observed. Overshoots are often observed in reaction progress curves run in deuterium oxide that are initiated with a single stereoisomer that is protiated at the Ca position (Fig. 7.3). The optical activity is monitored by polarimetry or circular dichroism (CD). At equilibrium, the signal is zero, since the product is a racemic mixture of d- and L-isomers. However, when there is a significant substrate-derived KIE on the reverse direction (product being fully deuterated in a two-base mecha-... 

Table 21.1 compares some of the common properties of H2O with those of D2O. Deuterium oxide, or heavy water as it is commonly called, is used in some nuclear reactors as a coolant and a moderator of nuclear reactions (see Chapter 23). D2O can be... 

The glycosidase-inhibitory properties of sugar-shaped cyclic thioureas were first, explored by Lehmann and co-workers,414 who obtained the hexa-hydropyrimidine-2-thione glucomimetic 271 by thiocarbonylation of the diamine precursor 270. Compound 271 was a very weak inhibitor of sweet-almond /3-glucosidasc, and this was ascribed to the lack of the OH group at the homologous position of C-3 in n-glucopyranosidcs. Moreover, an unexpected preference for the irons-diaxial conformation in deuterium oxide solution. was observed (Scheme 73). 

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