Theoretical dynamic studies on the reactions of CH3C(O)CH3-nCl(n) (n = 0-3) with the chlorine atom.
The theoretical investigations were performed on the reaction mechanisms for the title reactions CH(3)C(O)CH(3) + Cl --> products (R1), CH(3)C(O)CH(2)Cl + Cl --> products (R2), CH(3)C(O)CHCl(2) + Cl --> products (R3), and CH(3)C(O)CCl(3) + Cl --> products (R4) by ab initio direct dynamics approach. Two different reaction channels have been found: abstract of the H atom from methyl (--CH(3)) group or chloromethyl (--CH(3-n)Cl(n)) group of chloroacetone and addition of a Cl atom to the carbon atom of the carbonyl group of chloroacetone followed by methyl or chloromethyl eliminations. Because of the higher potential energy barrier, the contribution of addition-elimination reaction pathway to the total rate constants is very small and thus this pathway is insignificant in atmospheric conditions. The rate constants for the H-abstraction reaction channels are evaluated by using canonical variational transition state theory incorporating with the small-curvature tunneling correction. Theoretical overall rate constants are in good agreement with the available experimental values and decrease in the order of k(1) > k(2) > k(3) > k(4). The results indicate that for halogenated acetones the substitution of halogen atom (F or Cl) leads to the decrease in the C--H bond reactivity and more decrease of reactivity is caused by F-substitution.
Ji
Yue-Meng
YM
Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun, Jilin, 130023, People's Republic of China.
Zhao
Xiao-Lei
XL
Liu
Jing-Yao
JY
Wang
Ying
Y
Li
Ze-Sheng
ZS
D000096:Acetone / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D003198:Computer Simulation; D006843:Hydrocarbons, Chlorinated / Q000138:chemical synthesis* / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D011789:Quantum Theory; D013696:Temperature; D013816:Thermodynamics
D006843:Hydrocarbons, Chlorinated; D000096:Acetone; D002713:Chlorine