Automated model building and modeling of alcohol oxidation in high temperature water

Software for the computer generation of kinetic models was exploited to con struct a mechanistic kinetic model for alcohol oxidation in high temperatur e (300 less than or equal to T/degrees C less than or equal to 380) water. The complexities of the oxidation mechanism were captured by a detailed mec hanism consisting of eight reaction families. These included hydrogen abstr action by oxygen, hydrogen abstraction by radical, beta-scission, non-termi nating radical reactions, isomerizations, decomposition, molecular addition and termination steps. The mechanistic model was generated computationally , using the graph theory notions where the molecules and radicals are repre sented as atomic connectivity matrices and the reactions as matrix operator s. The free-radical kinetics of C1-C4 alcohols exhibited features of both g as-phase combustion and liquid-phase oxidation chemistry. The imposition of Evans-Polyanyi relationships for the associated rate constants provided a significant reduction in model parameters with little loss of predictive ca pability. Kinetic parameter vectors, one for each reaction family, obtained by optimizing the model predictions to pure-component ethanol data provide d a very good fit to pure component kinetics of other alcohols, as well as mixture kinetics.