Theoretical investigation of the gas-phase reactions of CF2ClC(O)OCH3 with the hydroxyl radical and the chlorine atom at 298 K

Abstract

A Theoretical study on the mechanism of the reactions of CF2ClC(O)OCH3 with the OH radical and Cl atom is presented. Geometry optimization and frequency calculations have been performed at the MPWB1K/6-31+G(d,p) level of theory and energetic information is further refined by calculating the energy of the species using G2(MP2) theory. Transition states are searched on the potential energy surface involved during the reaction channels and each of the transition states are characterized by presence of only one imaginary frequency. The existence of transition states on the corresponding potential energy surface is ascertained by performing intrinsic reaction coordinate (IRC) calculation. Theoretically calculated rate constants at 298 K and atmospheric pressure using the canonical transition state theory (CTST) are found to be in good agreement with the experimentally measured ones. Using group-balanced isodesmic reactions as working chemical reactions, the standard enthalpies of formation for CF2ClC(O)OCH3, CF2ClC(O)OCH2 and CF3C(O)OCH3 are also reported for the first time.

Thermal stability and decomposition mechanism of HFO‐1336mzz(Z) as an environmental friendly working fluid: Experimental and theoretical study

“…The DFT method has been widely employed to investigate the dissociation mechanisms of biomass and organics . Working fluids are decomposed via the breakage of the weakest bond and the subsequent reactions involving the H‐abstraction and F‐abstraction reactions and combination reactions to produce the small products.…”

“…The DFT method has been widely employed to investigate the dissociation mechanisms of biomass [26][27][28][29][30][31][32][33][34][35] and organics. [36][37][38][39] Working fluids are decomposed via the breakage of the weakest bond and the subsequent reactions involving the H-abstraction and F-abstraction reactions 19 and combination reactions 40 to produce the small products. Thirty-four pathways of HFO-1336mzz(-Z) dissociation based on FTIR measured results and related experiences are analyzed in this study.…”

Theoretical Studies of the Reactions CFxH3−xCOOR+Cl and CF3COOCH3+OH

“…To further understand the title reactions, it is important to compare their dynamics with that of similar systems (Cl atoms or OH radicals with CH 3 COOCH 3 , CH 2 FCOOCH 3 , CF 2 ClCOOCH 3 , CF 2 ClCOOCH 2 CH 3 , CF 3 COOCH 2 CF 3 ) 10–23. 59 For reaction CF 2 HCOOCH 3 (I) with a Cl atom, the rate constant of the H‐abstraction pathway from the CF 2 H group is 2.41×10 −14 cm 3 molecule −1 s −1 , and 5.08×10 −14 cm 3 molecule −1 s −1 for the pathway from the CH 3 group at 298 K. Obviously, the H atom of the CF 2 H group is harder to be abstracted than that of the CH 3 group at 298 K. Deka et al19 investigated the reaction CH 2 FCOOCH 3 +OH theoretically. Both conformers of CH 2 FCOOCH 3 were considered for the rate‐constant calculations, and the contribution from each of the conformers was found to be quite significant.…”

“…It is interesting to note that the rate constants of the reactions of the OH radical or the Cl atom with some FESs vary in the order: k CH3COOCH3 > k CH2FCOOCH3 > k CF2HCOOCH3 > k CF2ClCOOCH3 > k CF3COOCH3 10–12. 14–16, 18–21, 59 With Cl+R′COOCH 2 R′′ (R′=CF 2 Cl, CF 3 ; R′′=CH 3 , CF 3 ) as criterion, k CF2ClC(O)OCH2CH3 > k CF3C(O)OCH2CH3 > k CF3C(O)OCH2CF3 11–13. 17, 22, 23 Comparing the overall rate constants of R′C(O)OCH 2 CH 3 +Cl/OH with R′C(O)OCH 3 +Cl/OH (R′=CF 2 Cl, CF 3 ), we can find the following relationship: k CF2ClCOOCH2CH3 > k CF2ClCOOCH3 , k CF3COOCH2CH3 > k CF3COOCH3 .…”

Insight of UV-vis spectra and atmospheric implication for the reaction of ˙OH radical towards glyphosate herbicide and its hydrates

“…The quantity [cOH] ¼ 1.0 Â 10 6 molecule cm À3 is the global average atmospheric concentration of the cOH radicals. [70][71][72] In fact, other oxidants as O 3 , cNO x¼1-3 radicals, and Cl atom also contribute to the degradation of the gas in the troposphere. [70][71][72]75,76 However, they are less reactive compared to cOH radical, which is known as the 'atmospheric detergent'.…”