Reactions of chlorine atoms with ethane, propane, isobutane, fluoroethane, 1,1-difluoroethane, 1,1,1-trifluoroethane and cyclopropane

Abstract

Investigation of the kinetics of the abstraction of primary and tertiary hydrogen atoms by chlorine atoms indicates that the presence of an inert gas (hexafluoroethane) has a marginal effect. Improved Arrhenius parameters have been derived for these reactions and parameters found for the fluoroethanes .

Competitive photochlorination and kinetic isotope effects for hydrogen/deuterium abstraction from the methyl group in C2H6, C2D6, CH3CHCl2, CD3CHCl2, CH3CCl3, and CD3CCl3

“…The highest activation energy and the slowest rate are observed for CH,CC13 where there are only primary hydrogens. Similar trends have also been found in the case of fluoroethanes (13,16,17). A plausible qualitative explanation of these observations may be sought in terms of repulsive and electron withdrawal effects by the bound chlorine atom(s).…”

Product branching ratios in simple gas phase reactions

“…The results of the studies on propane and isobutene are summarized in Table 1. In general the agreement between the direct and indirect studies 62,63 is good and the experimental results provide a good test bed for comparing the predictions of various structure activity relationships (SAR). [64][65][66][67] Both of the temperature dependent studies show an increasing proportion of primary abstraction with increasing temperature, however, as the overall rate coefficients for the Cl reactions are either temperature independent (Cl + propane) Fig.…”

Kinetics and mechanism of the gas phase reaction of chlorine atoms with i-propanol

“…The reactivity of a -CH 3 group in i-propanol is substantially (approximately a factor of 5) less than that in an alkane. Combining the relative reactivity of primary compared to tertiary C-H bonds in (CH 3 ) 3 CH reported by Cadman et al20 of 1.82 (average of determinations with/without hexafluoroethane diluent) with the average of recent measurements[21][22][23][24][25] of k(Cl + (CH 3 ) 3 CH) = 1.4 Â 10 À10 we derive a reactivity of the tertiary C-H bond of 4.96 Â 10 À11 cm 3 molecule À1 s À1 . The tertiary C-H bond in i-propanol is approximately 40% more reactive than the tertiary C-H bond in i-butane.…”