Atmospheric degradation of HCFO-1233zd(E) initiated by OH radical, Cl atom and O3 molecule: Kinetics, reaction mechanisms and implications

Rao, Pradeep Kumar; Gejji, Shridhar P.

doi:10.1016/j.jfluchem.2018.05.001

Cited by 10 publications

(12 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recent studies have demonstrated the versatile applicability of Minnesota class of density functionals for various chemical processes. − Hence, the new-generation density functional M06-2X in conjunction with def2-TZVP and aug-cc-pVTZ basis sets was employed in the present study. Also, the highly correlated method, CCSD(T)/def2-TZVP was employed for benchmarking the model chemistries.…”

Section: Methodsmentioning

confidence: 99%

Molecular Hydration of Carbonic Acid: Ab Initio Quantum Chemical and Density Functional Theory Investigation

Kulkarni

2019

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

Section: Methodsmentioning

confidence: 99%

Molecular Hydration of Carbonic Acid: Ab Initio Quantum Chemical and Density Functional Theory Investigation

Kulkarni

2019

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…Because the rate coefficient for reaction with OH is very slow, this 1% quantum yield results in (11.0 ± 5.5)% of CF 3 CHO molecules in the atmosphere decomposing via this CHF 3 pathway, resulting in a secondary GWP = 1400 ± 700 for CF 3 CHO. CF 3 CHO is formed in 100% molar yield from the atmospheric decomposition of HFO-1234ze [6] as well as from the decomposition of other HFOs [25] and HFCs [26]. This introduces a concern that HFOs being considered as replacement gases for air conditioning and other industrial uses might have significant impact as climate change agents.…”

Section: Implications For Hfo Usementioning

confidence: 99%

Photodissociation of CF3CHO provides a new source of CHF3 (HFC-23) in the atmosphere: implications for new refrigerants.

Hansen

Campbell

Kable

2021

Preprint

View full text Add to dashboard Cite

Throughout the last century, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) were the most widely used refrigerants. However, it was discovered that they released reactive chlorine in the upper atmosphere causing the hole in the ozone layer and they were phased out by the 1987 Montreal Protocol [1]. They were replaced by hydrofluorocarbons (HFCs), which contain no chlorine and do not damage the ozone layer. However, HFCs are potent greenhouse gases and they were phased out in a 2016 amendment to the Montreal Protocol [2]. The latest evolution of these refrigerants is the hydrofluoroolefins (HFOs). These molecules have no chlorine and incorporate a carbon-carbon double bond to greatly reduce their atmospheric lifetime, and hence their contribution as a greenhouse gas. In this work, we demonstrate that one of the most important HFOs in current use ultimately decomposes partially into HFC-23 (CHF3) in the atmosphere. HFC-23 is one of the most potent greenhouse gases known, and the most potent HFC. Despite its phaseout, the observed emissions of HFC-23 have been increasing recently and were the largest in history in 2018 with no conclusive explanation [3]. This work suggests that the production of HFOs might be partially responsible.

show abstract

“…Hydrofluoroolefins (HFOs) are a class of molecules that find use in modern day refrigerants. − They are fourth-generation refrigerants manufactured to replace chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). In contrast to CFCs, HCFCs, and HFCs, refrigerants containing HFOs and HFO blends contain no ozone depletion potential and very low global warming potential. , The latter characteristics are mostly due to their short lifetimes in the troposphere undergoing oxidation via tropospheric OH radicals and O 3 . , …”

Section: Introductionmentioning

confidence: 99%

“…4,5 The latter characteristics are mostly due to their short lifetimes in the troposphere undergoing oxidation via tropospheric OH radicals and O 3 . 6,7 Despite the plethora of research on HFO molecules, very little is known about the fate of their oxidation products once they are broken down in the atmosphere. Their nascent products may have non-negligible effects in the troposphere, while the π-perturbing effects of the F-substituent may enable these fluorinated oxidation products to display some interesting (photo)chemistry, which may appeal to the wider physical and organic chemistry communities.…”

Section: Introductionmentioning

confidence: 99%

Modeling the Ground- and Excited-State Unimolecular Decay of the Simplest Fluorinated Criegee Intermediate, HFCOO, Formed from the Ozonolysis of Hydrofluoroolefin Refrigerants

Poirier,

Guidry,

Ratliff

et al. 2023

J. Phys. Chem. A

View full text Add to dashboard Cite

Hydrofluoroolefins (HFO) are fourth-generation refrigerants designed to function as efficient refrigerants with no ozone depletion potential and zero global warming potential. Despite extensive studies on their chemical and physical properties, the ground- and excited-state chemistry of their atmospheric oxidation products is less well understood. This study focuses on the ground- and excited-state chemistry of the simplest fluorinated Criegee intermediate (CI), fluoroformaldehyde oxide (HFCOO), which is the simplest fluorinated CI formed from the ozonolysis of HFOs. HFCOO contains syn- and anti-conformers, which have Boltzmann populations of, respectively, 87 and 13% at 298 K. For both conformers, the calculated ground-state reaction energy profiles associated with cyclization to form fluorodioxirane is lower than the equivalent unimolecular decay path in the simplest CI, H2COO, with anti-HFCOO returning a barrier height more than half of that of H2COO. The excited-state dynamics reveal that photoexcitation to the bright S2 state of syn-HFCOO and anti-HFCOO is expected to undergo a prompt O–O fissionwith the former conformer expected to dissociate with an almost unity quantum yield and to form both O (1D) + HFCO (S0) and O (3P) + HFCO (T1) products. In contrast, photoexcitation of anti-HFCOO is expected to undergo an O–O bond fission with a non-unity quantum yield. The fraction of photoexcited anti-HFCOO that dissociates is predicted to exclusively form O (1D) + HFCO (S0) products, which is in sharp contrast to H2COO. The wider implications of our results are discussed from both physical and atmospheric chemistry perspectives.

show abstract

Atmospheric degradation of HCFO-1233zd(E) initiated by OH radical, Cl atom and O3 molecule: Kinetics, reaction mechanisms and implications

Cited by 10 publications

References 42 publications

Molecular Hydration of Carbonic Acid: Ab Initio Quantum Chemical and Density Functional Theory Investigation

Molecular Hydration of Carbonic Acid: Ab Initio Quantum Chemical and Density Functional Theory Investigation

Photodissociation of CF3CHO provides a new source of CHF3 (HFC-23) in the atmosphere: implications for new refrigerants.

Modeling the Ground- and Excited-State Unimolecular Decay of the Simplest Fluorinated Criegee Intermediate, HFCOO, Formed from the Ozonolysis of Hydrofluoroolefin Refrigerants

Contact Info

Product

Resources

About