Hydrogen donors, nonthermal reactivities

This investigation represents an attempt to assess the importance of nonthermal F-to-HF reactions in MNR experiments wdth reactive hydrogen donors. Reaction 4 and its thermal counterpart. Reaction 5, are... 

Table II. Nonthermal Reactivities for CI2 and Various Hydrogen Donors in Approximately 99.5 Mol % C2F6...

Figure 1 shows that the nonthermal H F yields obtained from low reactivity hydrogen donors at large C2F6 concentrations are negligibly important at ordinary MNR measurement sensitivity levels (J,4,5,6). However, for reactive substances corrections based on calibration experiments of the type reported here must be included in the kinetic analysis... 

Several conclusions follow from the present results (i) The per-bond nonthermal F-to-HF reactivities for Ci-Ce alkanes are roughly equivalent. Steric and/or bond strength eflFects in these substances may give rise to 10-15% reactivity diflFerences, (ii) The deuterium kinetic isotope eflFects for the per-bond nonthermal F-to-HF (DF) reactivities are quite small for cyclopentane and C2-C5 alkanes, (iii) The nonthermal corrections to the MNR H F yields for low-reactivity hydrogen donors are negligibly small, and (iv) For reactive hydrocarbons the uniform per-bond reactivity model may be combined with the simple collision fraction mixture law and hard sphere elastic cross sections obtained from gas-liquid critical data to estimate the nonthermal H F yield corrections in MNR experiments. The simple mixture law should provide a good description of the trace nonthermal yields in experiments in which the total thermal competitor concentration is held constant. 

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