Theoretical study on the Br + CH3SCH3 reaction

J Comput Chem. 2007 May;28(7):1153-9. doi: 10.1002/jcc.20646.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bromides / chemistry*
  • Computers
  • Models, Chemical*
  • Models, Molecular
  • Molecular Conformation
  • Sulfuric Acid Esters / chemistry*

Substances

  • Bromides
  • Sulfuric Acid Esters
  • dimethyl sulfate