Reactivity of haloalkanes in their reactions with the chlorine atom

Resumo

Experimental kinetic data on reactions of the chlorine atom with halogenated derivatives of methane and ethane (37 reactions) have been analyzed by the intersecting-parabolas method. The following five factors have an effect on the activation energy of these reactions: the enthalpy of reaction, triplet repulsion, the electronegativities of the reaction center atoms, the dipole–dipole and multidipole interactions between the reaction center and polar groups, and the effect of π electrons in the vicinity of the reaction center. The increments characterizing the contribution from each factor to the activation energy of the reaction have been calculated. The contribution from the polar interaction, ΔE_μ, to the activation energy depends on the dipole moment of the polar group and obeys the following empirical equation: ln(Δ_Eμ/Σμ) = −0.74 + 0.87(ΔE_μ/Σμ) − 0.084(ΔE_μ/Σμ)².