Theoretical study on the OH + CH3NHC(O)OCH3 reaction.

The multiple-channel reactions OH + CH3NHC(O)OCH3 → products are investigated by direct dynamics method. The optimized geometries, frequencies, and minimum energy path are all obtained at the MP2/6-311+G(d,p) level, and energetic information is further refined by the BMC-CCSD (single-point) method. The rate constants for every reaction channels, <EQNR>R1</EQNR>, <EQNR>R2</EQNR>, <EQNR>R3</EQNR>, and <EQNR>R4</EQNR>, are calculated by canonical variational transition state theory with small-curvature tunneling correction over the temperature range 200–1000 K. The total rate constants are in good agreement with the available experimental data and the two-parameter expression k(T) = 3.95 × 10-12 exp(15.41/T) cm3 molecule-1 s-1 over the temperature range 200–1000 K is given. Our calculations indicate that hydrogen abstraction channels <EQNR>R1</EQNR> and <EQNR>R2</EQNR> are the major channels due to the smaller barrier height among four channels considered, and the other two channels to yield CH3NC(O)OCH3 + H2O and CH3NHC(O)(OH)OCH3 + H2O are minor channels over the whole temperature range. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008 [ABSTRACT FROM AUTHOR]