Kinetics, mechanism, and global warming potentials of HFO-1234yf initiated by O3 molecules and NO3 radicals: insights from quantum study.

In the present investigation, the oxidation of HFO-1234yf (2,3,3,3-tetrafluoropropene) with O3 molecule and NO3 radical is studied by quantum chemical methods. The possible reaction pathways of the titled molecule with O3 molecule and NO3 radical are analyzed using M06-2X meta-hybrid density functional with the 6-311++G(d,p) basis set. We have further employed a series of single-point energy calculations by using a potentially high-level couple cluster method with single and double excitations, including perturbative corrections ((CCSD(T)) at the same basis set. The addition reaction of HFO-1234yf with O3 molecule is initiated by the formation of primary ozonide complex, which leads to the formation of various carbonyl compounds and Criegee intermediates. The calculated energy barriers and thermochemical parameters inferred that decomposition of C˙H2OO˙ and CF3CFO is slightly more preferred over the formation of CF3C˙FOO˙ and CH2O. Further, the NO3 radical addition at α- and β-sits of CF3CF〓CH2 molecule is analyzed in details. The individual and overall rate constants for each reaction pathways are calculated by using canonical transition state theory over the temperature range of 250-450 K. We have observed that the computed rate constants are in good agreement with the available experimental data. Atmospheric lifetimes and global warming potentials of the HFO-1234yf are also reported in this manuscript.