A W1 computational study on the kinetics of initial pyrolysis of a biodiesel model: Methyl propanoate

This work reports on the thermochemistry and kinetics of methyl propanoate (MePr) initial pyrolysis using the high ab initio multi-level composite W1 method over the temperature range 400-2000 K. Pyrolysis of MePr was simulated using ten complex bond fission reactions (R1-R10) and seven simple bond fission pathways (R11-R17). Rate coefficients of MePr decomposition have been estimated using transition state theory (TST) combined with tunneling through a one-dimensional Eckart barrier (Eck). Statistical Rice-Ramsperger-Kassel-Marcus (RRKM) tight theory has been also used in a pressure range of 0.001-100 atm. Our estimated rate coefficients are in strong agreement with previous literature and strongly pressure-dependent especially at high temperatures. In addition, thermodynamic parameters for MePr and some species involved in its decomposition reactions have been computed and compared with previous literature.