Solute and Solvent Dependencies of Intermolecular Interactions in Different Density Regions in Supercritical Fluids. A Generalization of the Three‐Density‐Region Solvation Mechanism

Sun, Ya‐Ping; Bunker, Christopher E.

doi:10.1002/bbpc.199500012

Cited by 36 publications

(3 citation statements)

References 88 publications

(36 reference statements)

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“…6 as a function of ρr, the latter being the best magnitude for analyzing the variation of fluid properties near the critical region. As it is usually found in supercritical mixtures, 54 three density regions are distinguished in the plot. Along the isotherm at Tr = 1.03, νmax values drop quasi-linearly within a wide density range, up to ρr = 0.6.…”

Section: Article Scitationorg/journal/jcpmentioning

confidence: 66%

Carbonyl stretch of CH⋯O hydrogen-bonded methyl acetate in supercritical trifluoromethane

Inafuku

Marceca

2020

The Journal of Chemical Physics

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Infrared spectroscopy in the gas phase was used to study the formation reaction of the CH⋯O hydrogen bonding complex involving the CH group of trifluoromethane, as a hydrogen donor, and the carbonyl group of methyl acetate, as a hydrogen acceptor, under different (T, p) conditions. The hydrogen-bonded carbonyl stretch of the molecular pair was monitored in dilute mixtures of methyl acetate in trifluoromethane at near-critical temperatures, from gas-to liquid-like densities. In the gas region, it was possible to discriminate the carbonyl signal of the hydrogen-bonded complex from that of the free ester and have access to their relative concentration. The equilibrium constant of the hydrogen bonding reaction and the standard enthalpy and entropy changes in the process were determined using the spectroscopic data. CH⋯O bonding was favored by lowering temperature or pressurizing F 3 CH in the mixture, remaining essentially no free carbonyl groups about the critical density. The carbonyl band of the hydrogen-bonded pair appeared as a single symmetric peak up to liquid-like densities, suggesting that the 1:1 methyl acetate-trifluoromethane complex has the most abundant stoichiometry. Spectral features as frequency shift and bandwidth of the hydrogen-bonded carbonyl were studied as a function of temperature and solvent-density. A bathochromic (red) vibrational shift was registered for the bound carbonyl band against density, with a sudden change in behavior in the near-critical region, while the width of this band remains mostly unresponsive.

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Section: Article Scitationorg/journal/jcpmentioning

confidence: 66%

Carbonyl stretch of CH⋯O hydrogen-bonded methyl acetate in supercritical trifluoromethane

Inafuku

Marceca

2020

The Journal of Chemical Physics

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“…Correction Functions for Local Density Enhancement. Four correction functions of local density enhancement evaluated in this work were obtained from the literature actual data at isothermal conditions with an infinite dilute concentration of a solute indicator in pure CO 2 using: (i) the fluorescence (g flour (ρ CO 2 )) method, 50 (ii) Raman (g Raman (ρ CO 2 )) method, 42 (ii) UV (g UV (ρ CO 2 )) method, 22,23,44 and (iv) MD (g MD (ρ CO 2 )) simulations 46 shown in eqs 7−10. Developments of the g(ρ CO 2 ) functions are given in detail in the Supporting Information (Section B, Figures S4−S7).…”

Section: Methodsmentioning

confidence: 99%

“…The modified predictive framework was applied to the estimation of π* values of four scCO 2 –cosolvent binary mixtures that are either measured in this work (MeOH and EtOH) or collected from the literature (2-propanol and 1,1,1,2-tetrafluoroethane , ). A comparison for predicted π* values of scCO 2 –cosolvent mixtures was made with four correction functions ( g (ρ CO 2 )) evaluated from the literature actual data using (i) the fluorescence method, (ii) Raman method, (ii) UV–vis method, ,, and (iv) MD simulations . Applications related to solubility, − extraction, ,,, and fractionation were examined and were analyzed with respect to the relationship of the π* values of scCO 2 –cosolvents with yield and selectivity in those applications.…”

Section: Introductionmentioning

confidence: 99%

Kamlet–Taft Dipolarity/Polarizability of Binary Mixtures of Supercritical Carbon Dioxide with Cosolvents: Measurement, Prediction, and Applications in Separation Processes

Duereh

Sugimoto

Ota

et al. 2020

Ind. Eng. Chem. Res.

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A flow-type apparatus and predictive framework were developed for measuring and estimating dipolarity/ polarizability (π*) values of binary mixtures of supercritical carbon dioxide (scCO 2 )−cosolvents. The π* values of scCO 2 with methanol and ethanol cosolvents (up to 10 mol %) are reported at the temperature ranging from 40 to 80 °C and pressure ranging from 10 to 20 MPa and were found to be dependent on fluid density. The predictive framework for scCO 2 −cosolvent mixtures proposed in this work was the modification by the addition of correction functions (g(ρ CO 2 )) of local density enhancement into the previous predictive framework for binary liquid nonpolar−polar mixtures [Ind. Eng. Chem. Res. 2019, 58, 18986−18996]. Four g(ρ CO 2 ) forms with a function of CO 2 density were evaluated by considering literature local density enhancements of pure CO 2 obtained from (i) fluorescence, (ii) Raman, (ii) UV−vis spectroscopic techniques, and (iv) molecular dynamics simulations. The framework was applied to the prediction of π* of four scCO 2 −cosolvent mixtures (methanol, ethanol, 2-propanol, and 1,1,1,2tetrafluoroethane (HFC134a)) and was found to give a reliable value with an overall relative deviation of 0.03 between the experimental and calculated data, where the fluorescence g(ρ CO 2 ) function provided a lower deviation than the other three functions. The application of the framework to separation processes showed that the π* values were found to explain the trends of solubility, extraction yield, and fractionation recovery. The π* values determined from the framework can be used to analyze solvent effect trends in many separation processes that required only cosolvent dipole moment, pure π* component, and CO 2 density (pressure and temperature).

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Photochemical and Photo‐induced Reactions

Tanko¹

1999

Chemical Synthesis Using Supercritical Fluids

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Solute and Solvent Dependencies of Intermolecular Interactions in Different Density Regions in Supercritical Fluids. A Generalization of the Three‐Density‐Region Solvation Mechanism

Cited by 36 publications

References 88 publications

Carbonyl stretch of CH⋯O hydrogen-bonded methyl acetate in supercritical trifluoromethane

Carbonyl stretch of CH⋯O hydrogen-bonded methyl acetate in supercritical trifluoromethane

Kamlet–Taft Dipolarity/Polarizability of Binary Mixtures of Supercritical Carbon Dioxide with Cosolvents: Measurement, Prediction, and Applications in Separation Processes

Photochemical and Photo‐induced Reactions

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