Isotopic exchange between hydrogen and

Isotopic Exchange between Hydrogen and Liquid Ammonia Catalyzed by Alkali Amides... 

As an example, in isotope exchange we will consider the dynamics of the isotope exchange between hydrogen and deuterium over a silver catalyst, supported on alumina. 

For example, the catalytic reaction of isotope exchange between hydrogen and deuterium proceeds through three (I-III) reaction paths... 

Most of the chemical properties of tritium are common to those of the other hydrogen isotopes. However, notable deviations in chemical behavior result from isotope effects and from enhanced reaction kinetics induced by the ( -emission in tritium systems. Isotope exchange between tritium and other hydrogen isotopes is an interesting manifestation of the special chemical properties of tritium. 

Fig. 4. Hydrogen isotope exchange between C6H and C6D6. Correlation of randomisation rate constant kF, with percentage d-character of the metallic bonds (4). 

The thermal decomposition, at least in the early stages, is reversible, as shown by the higher decomposition temperature in the presence of hydrogen than in vacuum or inert gas, and also by the existence of a rapid isotopic exchange between tetrahydroboride and deuterium at T > 625 K (Ziittel et al., 2003). 

Two mechanisms have been proposed to account for the deuterium enrichment (1) for organic molecules, high D/H ratios can be explained by ion molecule reactions that occur in interstellar space and (2) for the phyllosilicates the enrichment can be produced via isotope exchange between water and hydrogen (Robert et al. 2000). 

XVIII. Isotopic Exchange between Steam and Hydrogen.267... 

Symons, E. A. Clermont, M. J. Hydrogen isotope exchange between CF3H and water. 

To assess any differences in isotopic exchange of a kanes on microcrystalline and amorphous catalysts, we examined isotopic exchange between deuterium and two saturated hydrocarbons, cyclopentane and hexane. The range of reaction temperatures for cyclopentane was 175-275° and the molar ratio of deuterium to hydrocarbon was 5.6. Catalysts were activated at 400° first in helium and then, after runs on the amorphous catalyst, the catalyst was reactivated in hydrogen to make it microcrystalline. Two series of such runs were made. At 250°, reaction rates on the amorphous catalysts were as follows run 285, 0.40 mmoles per hour per gram of Cr203 run 296, 0.36. On the micro-crystalline catalyst, the exchange rates were, for run 288, 2.0 run 299, 1.1. These rates were computed by... 

Hydrogen atoms returning to the metal by reverse spillover can however initiate isomerisation between the butenes and isotopic exchange between labelled and unlabelled alkenes, after which the reaction is self-propagating. Since the amount of the initiator may be immeasurably smaU, it cannot necessarily be detected by... 

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