A Study of Factors Affecting Various Reactions of Thermal Decomposition of Ethyl Fluoroformate Using Ab Initio Quantum Mechanics Calculations

Abstract The thermal decomposition reaction of ethyl fluoroformate was investigated at two levels of theory of MP2 and DFT in the gas phase at three different proposed mechanisms. The geometry of transition state (TS) for these three mechanisms was obtained using the STQN theory and the scan method. The kinetic parameters, such as activation energy (Ea), Arrhenius rate constant (k(T)), and Arrhenius pre-exponential factor (A), were calculated for three paths of thermal decomposition based on activated complex theory. The geometry of TS was predicted for three proposed mechanisms. The results revealed that the barrier through TS1 to TS2 increased about 4–5 kJ/mol, but that through TS2 to TS3 increased between 15 and 50 kJ/mol, based on the level of theory for calculation. It means that the formation of TS3 is more difficult than the others. The calculated synchronicity values indicate that the proposed mechanisms do not correspond to a concerted and highly synchronous process.