A kinetic and thermochemical database for organic sulfur and oxygen compounds

Abstract

Potential energy surfaces and reaction kinetics were calculated for 40 reactions involving sulfur and oxygen. This includes 11 H₂O addition, 8 H₂S addition, 11 hydrogen abstraction, 7 beta scission, and 3 elementary tautomerization reactions, which are potentially relevant in the combustion and desulfurization of sulfur compounds found in various fuel sources. Geometry optimizations and frequencies were calculated for reactants and transition states using B3LYP/CBSB7, and potential energies were calculated using CBS-QB3 and CCSD(T)-F12a/VTZ-F12. Rate coefficients were calculated using conventional transition state theory, with corrections for internal rotations and tunneling. Additionally, thermochemical parameters were calculated for each of the compounds involved in these reactions. With few exceptions, rate parameters calculated using the two potential energy methods agreed reasonably, with calculated activation energies differing by less than 5 kJ mol⁻¹. The computed rate coefficients and thermochemical parameters are expected to be useful for kinetic modeling.