ab initio calculations and thermochemical analysis on C1 atom abstractions of chlorine from chlorocarbons and the reverse alkyl abstractions: Cl2 + R· ↔ Cl· + RCl
✍ Scribed by Jongwoo Lee; Joseph W. Bozzelli; J. P. Sawerysyn
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 523 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0538-8066
No coin nor oath required. For personal study only.
✦ Synopsis
Thermodynamic properties and Cp(T ) from 300 to for re-(⌬H Њ , S Њ 1500 K) f(298) (298) actants, adducts, transition states, and products in reactions of CH 3 and C 2 H 5 with Cl 2 are calculated using CBSQ//MP2/6-311G(d,p). Molecular structures and vibration frequencies are determined at the MP2/6-311G(d,p), with single-point calculations for energy at MP4(SDQ)/CbsB4, and MP2/CBSB3 levels of calculation with scaled QCISD(T)/6-311 ϩ G(d,p), vibration frequencies. Contributions of rotational frequencies for and Cp(T )'s are cal-SЊ (298) culated based on rotational barrier heights and moments of inertia using the method of Pitzer and Gwinn [1]. Thermodynamic parameters, and C P (T ), are evaluated for C 1 and C 2 chlo-⌬H Њ , S Њ , f(298) (298) rocarbon molecules and radicals. These thermodynamic properties are used in evaluation and comparison of (defined forward direction) reaction rate constants from Cl ϩ R : Cl ϩ RCl ؒ ؒ 2 the kinetics literature for comparison with the calculations. Data from some 20 reactions in the literature show linearity on a plot of Ea fwd vs. ⌬H rxn,fwd , yielding a slope of (0.38 Ϯ 0.04) and intercept of kcal/mole. A correlation of average Arrhenius preexponential (10.12 Ϯ 0.81