Aqueous phase hydration and hydrate acidity of perfluoroalkyl and n:2 fluorotelomer aldehydes

Rayne, Sierra; Forest, Kaya

doi:10.1080/10934529.2016.1141625

Cited by 2 publications

(2 citation statements)

References 37 publications

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“…These compounds are both derivatives and precursors of other well-known perfluorinated compounds and are thought to play an important role towards our understandings into the global cycling of these contaminants. [53][54][55] As part of our initial suite of calculations provided in Table 1, we found that the C 1 PFAld (CF 3 C(O)H) is expected to have a log K hydr,(g) ranging from 0.6 (G4(MP2)) to 1.8 (CBS-Q//B3), consistent with the experimental data. [35] Additional calculations at the CBS-Q//B3 and G4(MP2) levels on the C 2 (CF 3 CF 2 C(O)H), C 3 (CF 3 (CF 2 ) 2 C(O)H), and C 4 (CF 3 (CF 2 ) 3 C(O)H) PFAlds gave the following log K hydr,(g) : C 2 , 0.9 (CBS-Q//B3) and À0.3 (G4(MP2)); C 3 , 0.7 (CBS-Q//B3) and À0.4 (G4(MP2)); and C 4 , 1.1 (CBS-Q//B3) and À0.1 (G4 (MP2)).…”

Section: Substituentsupporting

confidence: 71%

A high‐level theoretical study into the atmospheric phase hydration, bond dissociation enthalpies, and acidity of aldehydes

Rayne¹,

Forest

2016

J of Physical Organic Chem

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CBS-Q//B3, G4(MP2), and G4 composite method calculations were used to estimate atmospheric phase standard state (298.15 K, 1 atm) free energies of hydration (Δ hydr G°( g) ), hydration equilibrium constants (log K hydr,(g) ), bond dissociation enthalpies (BDEs), and enthalpies (Δ d H°( g) ) and free energies (Δ d G°( g) ) of aldehydic proton acid dissociation for various substituted aldehydes with electron withdrawing and electron releasing groups. Good quality log K hydr,(g) correlations with the Swain-Lupton resonance effect parameters R and R + were found, allowing extension of the model to predict log K hydr,(g) values for 487 substituted aldehydes having available R-values and 108 substituted aldehydes having available R + values. Good correlations were also found between experimental aqueous phase hydration equilibrium constants (log K hydr,(aq) ) and summative R/R + values for peripheral substituents on a range of carbonyl derivatives (aldehydes, ketones, esters, and amides), suggesting that the structure-reactivity modeling approach can be extended to include all possible combinations of R 1 C(O)R 2 carbonyl substitution in both gas and aqueous systems. Computationally derived BDEs and Δ d H°( g) /Δ d G°( g) were in good agreement with the limited experimental and theoretical datasets. BDEs did not generally correlate with any of the Hammett substituent constants or Swain-Lupton parameters considered. Gas phase acidities exhibited high correlation coefficients with Hammett inductive substituent constants (σ I ) and field effect parameters (F), allowing these to be employed as surrogates for estimating the gas phase aldehydic proton acidities of a larger potential compound range. The resulting models will be of use in predicting the environmental behavior for a broad range of environmentally relevant compounds containing carbonyl functionalities.

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Section: Substituentsupporting

confidence: 71%

A high‐level theoretical study into the atmospheric phase hydration, bond dissociation enthalpies, and acidity of aldehydes

Rayne¹,

Forest

2016

J of Physical Organic Chem

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“…It has been reported that formaldehyde is efficiently converted to gaseous formic acid via a multiphase pathway involving a hydrated form of formaldehyde [276]. Earlier, using computational methods, Rayne and Forest [277] suggested that CF 3 CHO will be dominantly present as the hydrated form in aqueous solution. The reaction of OH radicals with the hydrated form of CF 3 CHO in the gas phase is known to be an effective route for formation of TFA (100%) [211]; however, to what extent CF 3 CHO could be removed from the atmosphere through wet scavenging and undergo multiphase chemistry is unknown.…”

Section: Sinks For Cf 3 Cho: a Photolytic Source Of Hfc-23 And Cf 3 C...mentioning

confidence: 99%

Changes in tropospheric air quality related to the protection of stratospheric ozone in a changing climate

Madronich

Sulzberger

Longstreth³

et al. 2023

Photochem Photobiol Sci

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Ultraviolet (UV) radiation drives the net production of tropospheric ozone (O3) and a large fraction of particulate matter (PM) including sulfate, nitrate, and secondary organic aerosols. Ground-level O3 and PM are detrimental to human health, leading to several million premature deaths per year globally, and have adverse effects on plants and the yields of crops. The Montreal Protocol has prevented large increases in UV radiation that would have had major impacts on air quality. Future scenarios in which stratospheric O3 returns to 1980 values or even exceeds them (the so-called super-recovery) will tend to ameliorate urban ground-level O3 slightly but worsen it in rural areas. Furthermore, recovery of stratospheric O3 is expected to increase the amount of O3 transported into the troposphere by meteorological processes that are sensitive to climate change. UV radiation also generates hydroxyl radicals (OH) that control the amounts of many environmentally important chemicals in the atmosphere including some greenhouse gases, e.g., methane (CH4), and some short-lived ozone-depleting substances (ODSs). Recent modeling studies have shown that the increases in UV radiation associated with the depletion of stratospheric ozone over 1980–2020 have contributed a small increase (~ 3%) to the globally averaged concentrations of OH. Replacements for ODSs include chemicals that react with OH radicals, hence preventing the transport of these chemicals to the stratosphere. Some of these chemicals, e.g., hydrofluorocarbons that are currently being phased out, and hydrofluoroolefins now used increasingly, decompose into products whose fate in the environment warrants further investigation. One such product, trifluoroacetic acid (TFA), has no obvious pathway of degradation and might accumulate in some water bodies, but is unlikely to cause adverse effects out to 2100. Graphical abstract

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Aqueous phase hydration and hydrate acidity of perfluoroalkyl and n:2 fluorotelomer aldehydes

Cited by 2 publications

References 37 publications

A high‐level theoretical study into the atmospheric phase hydration, bond dissociation enthalpies, and acidity of aldehydes

A high‐level theoretical study into the atmospheric phase hydration, bond dissociation enthalpies, and acidity of aldehydes

Changes in tropospheric air quality related to the protection of stratospheric ozone in a changing climate

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