Evidence of an odd–even effect on the thermodynamic parameters of odd fluorotelomer alcohols

Costa, José C. S.; Fulem, Michal; Schröder, Bernd; Coutinho, João A. P.; Monte, Manuel J.S.; Santos, Luı́s M. N. B. F.

doi:10.1016/j.jct.2012.03.027

Cited by 16 publications

(17 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Molar enthalpies of vaporization were calculated from the experimental data and the results compared with data from the literature for other perfluoroalcohols as well as their equivalent hydrogenated alcohols. Vapor pressure measurements were previously reported for the longer chained (CF 3 (CF 2 ) n CH 2 OH, n ¼ 5e9) odd fluorotelomers [6], but for the short chains studied in this work, experimental data has not been reported or is of insufficient accuracy. Molecular dynamics simulations were also performed and provide molecular level insight into the experimental results.…”

Section: Introductionmentioning

confidence: 82%

“…3. Also shown are the enthalpies of vaporization from the literature [6,23] for 1:1 FTOH, 2:1 FTOH, 3:1 FTOH and for longer chain alcohols from 6:1 FTOH to 10:1 FTOH. As can be seen, the vaporization enthalpy for the FTOH family increases almost linearly with chain length, displaying an average increment of 4.8 kJ mol À1 per each additional CF 2 group.…”

Section: Vapor Pressures and Enthalpies Of Vaporizationmentioning

confidence: 99%

“…3b, it can be seen that the enthalpies of vaporization of FTOH are consistently lower by 2e4 kJ/mol, than those of the hydrogenated alcohols [24], which also present a linear trend with approximately the same slope. In a recent paper [6], Costa et al concluded that the higher volatility of the longer fluorinated alcohols relative to their hydrogenated analogues is entropically driven, since they found that the enthalpies of vaporization were very similar for both families while the corresponding entropies were slightly higher. The results for the shorter FTOH obtained in the present work, however, confirm that the difference in vaporization enthalpies is larger than the experimental uncertainty, indicating that enthalpic contributions to the higher volatility of FTOH may be significant and cannot be ignored.…”

Section: Vapor Pressures and Enthalpies Of Vaporizationmentioning

confidence: 99%

See 2 more Smart Citations

Vapor pressure and liquid density of fluorinated alcohols: Experimental, simulation and GC-SAFT-VR predictions

Silva

Morgado

Haley

et al. 2016

Fluid Phase Equilibria

View full text Add to dashboard Cite

a b s t r a c tThe vapor pressure of four liquid 1H,1H-perfluoroalcohols (CF 3 (CF 2 ) n (CH 2 )OH, n ¼ 1, 2, 3, 4), often called odd-fluorotelomer alcohols, was measured as a function of temperature between 278 K and 328 K. Liquid densities were also measured for a temperature range between 278 K and 353 K. Molar enthalpies of vaporization were calculated from the experimental data. The results are compared with data from the literature for other perfluoroalcohols as well as with the equivalent hydrogenated alcohols. The results were modeled and interpreted using molecular dynamics simulations and the GC-SAFT-VR equation of state.

show abstract

Section: Introductionmentioning

confidence: 82%

Section: Vapor Pressures and Enthalpies Of Vaporizationmentioning

confidence: 99%

Section: Vapor Pressures and Enthalpies Of Vaporizationmentioning

confidence: 99%

See 1 more Smart Citation

Vapor pressure and liquid density of fluorinated alcohols: Experimental, simulation and GC-SAFT-VR predictions

Silva

Morgado

Haley

et al. 2016

Fluid Phase Equilibria

View full text Add to dashboard Cite

show abstract

“…Figure compares perfluorodiglyme and perfluorotriglyme Δ H vap values calculated from experimental vapor pressures to those of their hydrogenated counterparts; values for n -alkanes (CH 3 –(CH 2 ) n −2 –CH 3 ), perfluoroalkanes (CF 3 –(CF 2 ) n −2 –CF 3 ), n -alcohols (CH 3 –(CH 2 ) n −1 –OH), and 1 H ,1 H -perfluoroalcohols (CF 3 –(CF 2 ) n −2 –CH 2 –OH) , are also included for comparison. The PFPEs have significantly lower values of Δ H vap than their hydrogenated analogues, a trend which is not evident when comparing perfluoroalkanes to alkanes or 1 H ,1 H -perfluoroalcohols to alcohols.…”

Section: Resultsmentioning

confidence: 99%

“…58 nalkanes (CH 3 −(CH 2 ) n−2 −CH 3 ), 58 perfluoroalkanes (CF 3 −(CF 2 ) n−2 − CF 3 ), 58 n-alcohols (CH 3 −(CH 2 ) n−1 −OH), 58 and 1H,1H-perfluoroalcohols (CF 3 −(CF 2 ) n−2 −CH 2 −OH). 59,60 Lines are provided as a visual guide only.…”

Section: ■ Simulation Methodsmentioning

confidence: 99%

Perfluoropolyethers: Development of an All-Atom Force Field for Molecular Simulations and Validation with New Experimental Vapor Pressures and Liquid Densities

et al. 2017

View full text Add to dashboard Cite

A force field for perfluoropolyethers (PFPEs) based on the general optimized potentials for liquid simulations all-atom (OPLS-AA) force field has been derived in conjunction with experiments and ab initio quantum mechanical calculations. Vapor pressures and densities of two liquid PFPEs, perfluorodiglyme (CF-O-(CF-CF-O)-CF) and perfluorotriglyme (CF-O-(CF-CF-O)-CF), have been measured experimentally to validate the force field and increase our understanding of the physical properties of PFPEs. Force field parameters build upon those for related molecules (e.g., ethers and perfluoroalkanes) in the OPLS-AA force field, with new parameters introduced for interactions specific to PFPEs. Molecular dynamics simulations using the new force field demonstrate excellent agreement with ab initio calculations at the RHF/6-31G* level for gas-phase torsional energies (<0.5 kcal mol error) and molecular structures for several PFPEs, and also accurately reproduce experimentally determined densities (<0.02 g cm error) and enthalpies of vaporization derived from experimental vapor pressures (<0.3 kcal mol). Additional comparisons between experiment and simulation show that polyethers demonstrate a significant decrease in enthalpy of vaporization upon fluorination unlike related molecules (e.g., alkanes and alcohols). Simulation suggests this phenomenon is a result of reduced cohesion in liquid PFPEs due to a reduction in localized associations between backbone oxygen atoms and neighboring molecules.

show abstract

Photoinduced Reductive Decomposition of Perflurooctanoic Acid in Water: Effect of Temperature and Ionic Strength

Zhang

Zhao

et al. 2014

CLEAN Soil Air Water

View full text Add to dashboard Cite

Aqueous photo‐reductive decomposition of perflurooctanoic acid (PFOA) was investigated as a function of temperature (293, 298, and 313 K) and ionic strength (2.5, 5.0, or 20.0 mmol/L as NaCl). As an advanced reduction process, iodide was used under UV irradiation to produce highly reactive reducing reagent hydrated electrons. PFOA was reduced by hydrated electrons and short‐chain perfluorinated acid intermediates including perfluoroheptanoic acid, perfluorohexanoic acid, perfluoropentanoic acid, perfluorobutyric acid, pentafluoropropionic acid, and trifluoroacetic acid were detected during the reaction. In this study, the same intermediates were observed under different temperature and ionic strength conditions. It was found that the increase of reaction temperature could positively affect the decomposition of PFOA. Defluorination of PFOA was observed to increase as the temperature increased. After 6 h, the defluorination efficiency increased from 47.71% to 80.91% when the system temperature increased from 293 to 313 K. As the temperature increased, the maximum concentration of the six short‐chain perfluorinated acid intermediates decreased. Meanwhile, there was a positive correlation between the ionic strength and PFOA decomposition rate. According to the Brønsted–Bjerrum equation, ZA ZB was calculated to be 2.2, indicating that both single‐charged and double‐charged species play a role during the decomposition process.

show abstract

Evidence of an odd–even effect on the thermodynamic parameters of odd fluorotelomer alcohols

Cited by 16 publications

References 59 publications

Vapor pressure and liquid density of fluorinated alcohols: Experimental, simulation and GC-SAFT-VR predictions

Vapor pressure and liquid density of fluorinated alcohols: Experimental, simulation and GC-SAFT-VR predictions

Perfluoropolyethers: Development of an All-Atom Force Field for Molecular Simulations and Validation with New Experimental Vapor Pressures and Liquid Densities

Photoinduced Reductive Decomposition of Perflurooctanoic Acid in Water: Effect of Temperature and Ionic Strength

Contact Info

Product

Resources

About