Theoretical study on the Br + CH3SCH3 reaction.
The multiple-channel reactions Br + CH(3)SCH(3) --> products are investigated by direct dynamics method. The optimized geometries, frequencies, and minimum energy path are all obtained at the MP2/6-31+G(d,p) level, and energetic information is further refined by the G3(MP2) (single-point) theory. The rate constants for every reaction channels, Br + CH(3)SCH(3) --> CH(3)SCH(2) + HBr (R1), Br + CH(3)SCH(3) --> CH(3)SBr + CH(3) (R2), and Br + CH(3)SCH(3) -->CH(3)S + CH(3)Br (R3), are calculated by canonical variational transition state theory with small-curvature tunneling correction over the temperature range 200-3000 K. The total rate constants are in good agreement with the available experimental data, and the two-parameter expression k(T) = 2.68 x 10(-12) exp(-1235.24/T) cm(3)/(molecule s) over the temperature range 200-3000 K is given. Our calculations indicate that hydrogen abstraction channel is the major channel due to the smallest barrier height among three channels considered, and the other two channels to yield CH(3)SBr + CH(3) and CH(3)S + CH(3)Br are minor channels over the whole temperature range.
Zhang
Hui
H
College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150080, People's Republic of China.
Zhang
Gui-Ling
GL
Wang
Li
L
Liu
Bo
B
Yu
Xiao-Yang
XY
Li
Ze-Sheng
ZS
D001965:Bromides / Q000737:chemistry*; D003201:Computers; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D013463:Sulfuric Acid Esters / Q000737:chemistry*
D001965:Bromides; D013463:Sulfuric Acid Esters; C007482:dimethyl sulfate