Isotope exchange reaction

The activation energies for these reactions are 25, 42 and 54 kJ, respectively (see [232]). The increase in activation energies in the order H2O NH3 CH4 

An isotope exchange reaction can be treated also as a displacement reaction. If the displaced atom or radical is bound to a tetrahedral carbon atom, the displacement reaction can cause inversion. The inversion mechanism can be schematically described for the reaction D + RCH2CI - RCHDCl + H as follows  

In the activated state the three species (H, Cl, R) bonded to the attacked C atom are arranged in a single plane normal to the straight line D. .. C. .. H. 

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Isotopic Exchange Reactions. Exchange reactions between the isotopes of hydrogen are well known and well substantiated. The equihbrium constants for exchange between the various hydrogen molecular species have been documented (18). Kinetics of the radiation-induced exchange reactions of hydrogen, deuterium, and tritium have been critically and authoritatively reviewed (31). The reaction T2 + H2 — 2HT equiUbrates at room temperature even without a catalyst (30). 

Pyridinium sulfate, bis-l,2,4,6-tetramethyl-hydrogen isotope exchange reactions, 2, 194 Pyridinium-1 -sulfonates reactions, 2, 34... 

Radioactive isotopes of the halogens have found use in the study of isotope-exchange reactions and the mechanisms of various other reactions.The properties of some of the most used isotopes are in Table 17.5. Many of these isotopes are available commercially. A fuller treatment with detailed references... 

Fraction F3 catalyzes an isotope exchange reaction between CO and the carbonyl group of acetyl-CoA. ... 

This study presents kinetic data obtained with a microreactor set-up both at atmospheric pressure and at high pressures up to 50 bar as a function of temperature and of the partial pressures from which power-law expressions and apparent activation energies are derived. An additional microreactor set-up equipped with a calibrated mass spectrometer was used for the isotopic exchange reaction (DER) N2 + N2 = 2 N2 and the transient kinetic experiments. The transient experiments comprised the temperature-programmed desorption (TPD) of N2 and H2. Furthermore, the interaction of N2 with Ru surfaces was monitored by means of temperature-programmed adsorption (TPA) using a dilute mixture of N2 in He. The kinetic data set is intended to serve as basis for a detailed microkinetic analysis of NH3 synthesis kinetics [10] following the concepts by Dumesic et al. [11]. 

The most fundamental approach to assessing lability of complexes is by determination of the rate of isotopic exchange reactions. In the technetium-complex systems, no study of the exchange reaction on the central metal ion has been reported, but several reports have been published on isotopic exchange by ligand substitution. 

The isotopic exchange reaction by ligand substitution can be expressed in general as... 

The tritiation procedures given in Tab. 13.1 all have serious limitations/disadvan-tages. Thus for all three hydrogen isotope exchange reactions HTO is used as the do-... 

Ammonia liquid, isotope exchange reactions of organic compounds in, 1, 156... 

Isotope exchange reactions, hydrogen, of organic compounds in liquid ammonia, 1,150 Isotope exchange reactions, oxygen, of organic compounds, 3,123 Isotopes and organic reaction mechanisms, 2, 1... 

Oxyacids of sulphur and their anhydrides, mechanisms and reactivity in reactions of organic, 17, 65 Oxygen isotope exchange reactions of organic compounds, 3, 123... 

Juliusberger, F., B. Topley and J. Weiss Isotopic Exchange Reactions... 

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