Theoretical studies on atmospheric chemistry of CHF 2 CF 2 CH 2 OH: Reaction with OH radicals, lifetime and global warming potentials

Kinetics of Reactions of CHF2CF2CH2OH with Cl Atoms and CHF2CF2CHO with OH Radicals and Atmospheric Degradation Pathways of CHF2CF2CH2OH: A Theoretical Investigation

“…It has been reported in our previous work that the energy difference between the two most stable conformers (A and B) of CHF 2 CF 2 CH 2 OH is only 1.88 kJ mol −1 at the M06‐2X/6‐311++G(d,p) level. At MP2/6‐311++G(d,p) level, this difference in energy is found to be 2.28 kJ mol −1 and at the CCSD(T)//MP2/6‐311++G(d,p) level this difference in energy is 2.16 kJ/mol.…”

“…For convenience, we have labeled the transition states (TS) and radicals (Rad) associated with conformer A with subscript A (i. e. TS1 A , TS2 A , TS3 A , Rad1 A , Rad2 A and Rad3 A ) and that of conformer B with subscript B (i. e. TS1 B , TS2 B , TS3 B , Rad1 B , Rad2 B and Rad3 B ). Similar to H–abstraction reaction by OH radical, H–abstraction from CHF 2 CF 2 CH 2 OH by Cl atom also involves three potential channels for each of the two conformers: (i) H‐abstraction channel from the –CHF 2 site (ii) H–abstraction channel from the –CH 2 – site and (iii) H‐abstraction channel from the –OH site. It is to be noted that although the two H atoms in the –CH 2 – site are not strictly equivalent but only one TS could be located for this site.…”

“…In our previous work, we studied the kinetics of the reaction of CHF 2 CF 2 CH 2 OH with OH radical . One of the aims of our present study is to obtain detailed theoretical insight of the kinetics, mechanism and thermochemistry of the reaction of CHF 2 CF 2 CH 2 OH with Cl atoms which will assist in determining its effective atmospheric lifetime.…”

Theoretical Insight into the Kinetics of H‐Abstraction Reaction of CHF2CH2OH with OH Radical, Atmospheric Lifetime and Global Warming Potential

“…At 300 K, our calculated k OH value (2.44×10 −13 cm 3 molecule −1 s −1 ) is also in fairly good agreement with the experimental value of (2.52±0.44) ×10 −13 cm 3 molecule −1 s −1 reported by Kovács et al . The rate coefficient of CHF 2 CH 2 OH+OH reaction is found to be slightly greater than that for the CHF 2 CF 2 CH 2 OH+OH reaction (1.65×10 −13 cm 3 molecule −1 s −1 at 298 K), possibly due to the deactivating effect of the ‐CF 2 group in CHF 2 CF 2 CH 2 OH. As expected the H‐abstraction from the –CH 2 – channel (R2) is found to be the major reaction channel throughout the temperature range of 250–500 K contributing almost 85% to the total rate coefficient, the contribution from the other two reaction channels (R1 and R3) towards the total rate coefficient is not more than 15%.…”

“…On the other hand, atmospheric lifetime is primarily determined by the rate of the reactions of HFA with the various free radicals present in the atmosphere. A number of studies have been carried out on the reactions of fluorinated alcohols with various oxidants like OH radical and Cl atoms . It is to be noted that in the theoretical studies carried out on kinetics of reactions of HFA molecules with OH radical or Cl atoms, H‐abstraction from the –CH 2 – group next to the hydroxyl (OH) group of the HFA molecule has been reported as the major reaction channel.…”