Tropospheric Oxidation of 1,1,2,3-Tetrafluoropropene (CF2=CF–CH2F) Initiated by ·OH Radical and Aerial Degradation of Its Product Radicals

Abstract

It is essential to understand the tropospheric chemistry and environmental impact of 1,1,2,3-tetrafluoropropene (CF2=CF–CH2F) before its wide-scale applications. So, in this present work, we have performed the quantum chemical calculations of the ·OH radical initiated oxidation of CF2=CF–CH2F. First, all the reaction species of the title reaction are optimized at the M06-2X/6-311+G(d,p) level of theory and then the energies are refined at the CCSD(T) level with the same basis set. The relative energy and thermochemistry estimations indicate that the addition reactions of the ·OH radical to the carbon atoms of the double bond of CF2=CF–CH2F are energetically and thermodynamically more dominant rather than the direct H-abstraction reactions by the ·OH radical. The rate constant and branching ratio analysis also indicate the favorability of the ·OH-addition reactions over the H-abstraction reactions. The estimated overall rate constant at 298.15 K for this reaction is found to be 9.27 × 10–13 cm3 molecule–1 s–1 computed by variational transition state theory. The atmospheric lifetime of CF2 = CF–CH2F is calculated as 12.5 days with respect to ·OH reaction. The radiative efficiency is calculated as 0.016 W m–2 ppb–1, and global warming potentials of CF2=CF–CH2F for the different time horizons are significantly low. Further, photochemical ozone creation potential is estimated as 5.55. Finally, aerial degradation of the ·OH-addition product radicals was studied in the presence of the NO radical using the same quantum chemical method. From this degradation study, we have observed that CF2(OH)COF, FCOCH2F, FCFO, FCOOH, and ·CH2F are formed as end products.