Ab initio chemical kinetic study on the reactions of ClO with C2H2 and C2H4.
The mechanisms for the reactions of ClO with C(2)H(2) and C(2)H(4) have been investigated at the CCSD(T)/CBS level of theory. The results show that in both systems, the interaction between the Cl atom of the ClO radical and the triple and double bonds of C(2)H(2) and C(2)H(4) forms prereaction van der Waals complexes with the O-Cl bond pointing perpendicularly toward the π-bonds, both with 2.1 kcal/mol binding energies. The mechanism is similar to those of the HO-C(2)H(2)/C(2)H(4) systems. The rate constants for the low energy channels have been predicted by statistical theory. For the reaction of ClO and C(2)H(2), the main channels are the production of CH(2)CO + Cl (k(1a)) and CHCO + HCl (k(1b)), with k(1a) = 1.19 × 10(-15)T(1.18) exp(-5814/T) and k(1b) = 6.94 × 10(-21) × T(2.60) exp(-6587/T) cm(3) molecule(-1) s(-1). For the ClO + C(2)H(4) reaction, the main pathway leads to C(2)H(4)O + Cl (k(2a)) with the predicted rate constant k(2a) = 2.13 × 10(-17)T(1.52) exp(-3849/T) in the temperature range of 300-3000 K. These rate constants are pressure-independent below 100 atm.
Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
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Lin