Water catalyzed atmospheric oxidation of 1,1,2,2- tetrafluoroethene (TFE) with ozone: a computational study.

Abstract

Context: 1,1,2,2- tetrafluoroethene (TFE) is a class of per fluoroalkenes. The reaction of TFE with ozone is significant in the atmospheric oxidation of per fluoroalkenes. Kinetics of TFE + O₃ reaction in absence of as well as in presence of single water molecule act as catalyst has been analysed in gas phase as well as in solvent phase. The impact of water solvated environment is demonstrated to be significant to the extent that even single water molecules can function as catalysts in the ozonolysis of titled molecule. The computations related to the coordination of a single water molecule illustrate distinctly the notable decrease in the energy barrier and the substantial lowering of the activation energy. The investigation revealed that the mechanism of this reaction, which is facilitated by water as catalyst presents greater kinetic benefits compared to its non-catalytic counterpart. Calculated rate constant for water catalyzed and non catalyzed ozonolysis of titled molecule were estimated to be 1.0 × 10^-16 cm³molecule^-1 s^-1 and 3.0 × 10^-17 cm³molecule^-1 s^-1respectively. The atmospheric lifetimes, radiative forcing and global warming potential (GWP) have been determined as well.

Methods: All electronic structure calculations have been done employing Gaussian 09 software package. Geometry optimizations and frequency calculations have been performed using DFT/M06-2X/6-311 + G(d,p) method. The energies were further refined and potential energy were constructed at CCSD(T)/6-311 + G(d,p) level.