Arrhenius parameters, anomalous

Fig. 3 Hydrogen tunneling according to the Bell model can generate anomalous isotopic Arrhenius parameters. A semiclassical model with = 0 (thus Ah = A ) and...

Later the second term becomes small and k = Arrhenius parameters for (19) found by various workers are shown in Table 3. The work of Bodenstein and Ramstetter shows the anomalous initial rate found by Ashmore and Burnett and the data have been recalculated by the latter authors to obtain the values shown in Table 3. The technique used by Rosser and Wise ensured that the values of the... 

These A-factors are anomalously low and probably indicate that the Arrhenius parameters have been underestimated (see text). 

The anomalous low Arrhenius parameters for the reactions between CF3 and CjHs Br or CgF Br [327] (see Table 26) have been attributed to pseudo bromine transfer according to... 

The determination of the Arrhenius parameters for the alkaline hydrolysis of a series of sulphonate esters (Table 2) shows that the reactivity difference in sulphonates arises from a combination of entropy and enthalpy effects, although the latter is likely to be the dominant factor156. The different mechanism of hydrolysis (ElcB) of phenyl toluene-a-sulphonate 43 shows up clearly in the anomalous value of AS. ... 

CF2 CF2 < CF2 CF-CH CHMe < CF2 CF CH CH2 < CF2 CF-CF CF2 Approximate Arrhenius parameters have been obtained for the reaction of oxygen atoms ( F), from the mercury-sensitized decomposition of nitrous oxide, with the fluoroethylenes at two temperatures (25 and 150 °C) using the olefin CH2 C(CFs)Me as reference compound. All the fluoroethylenes appear less reactive than ethylene again with the exception of tetrafluoroethylene, reactivity being least for cis-l,2-di-fluoroethylene. The differences appear largely due to differences in activation energy, and the anomalous reactivity of tetrafluoroethylene is noteworthy. 

Anomalous isotope effects on Arrhenius parameters in proton transfer reactions in solution (L = H or D)... 

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