First-order tritiation rate constant

This study was extended by Satchell517, who investigated the effect of stannic chloride with various Bronsted acids on the rate of tritiation of toluene (excess) at 25 °C. Using tritium-hydrogen chloride the data in Table 153 were obtained, and whereas the first-order rate coefficients were closely proportional to the stannic chloride concentration, they were relatively independent of the total concentration of hydrogen chloride at a constant tritium chloride concentration, the small rate... 

Before the full Arrhenius diagram is discussed in detail, let us first include the results of a subsequent study of Braun et al. [18e] who measured also the rate constants feHT and k n using liquid state NMR of tritiated porphyrin dissolved in toluene. In order to discuss the new data it is convenient to convert the rate constants k L into the rate constants k using Eq. (6.31) which is naturally valid also... 

We made several measurements. From the rate of the over-all reaction, we determined fccat Then we measured the rate of the tritium transfer from the enzyme-coenzyme ( H) complex, containing coenzyme tritiated at C-5, to the reaction product. This is a first-order process in the amount of tritium in the coenzyme, and we obtained a rate constant, 2 ... 

Electrophilic deuteration of pyridine has not been described. Pyridine underwent no exchange with tritiated water after 40 h at 207 in a solution of //o —12. However, under similar conditions the 3- and 5-hydrogen atoms of 2,6-lutidine, 2,4,6-collidine and 1,2,4,6-tetramethylpyridinium sulphate were replaced by tritium. The first-order rate constants varied linearly with //o, showing that the exchange involved the pyridinium ions and not the free bases. This conclusion also followed from comparison with the reaction... 

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