Air-Water Partitioning of Environmentally Important Organic Compounds: An Environmental Chemistry or Integrated Laboratory Experiment

Ramachandran, B.; Allen, John M.; Halpern, Arthur M.

doi:10.1021/ed073p1058

Cited by 21 publications

(7 citation statements)

References 9 publications

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“…The most widely used methods for direct measurement of H values are batch air stripping [4,5], equilibrium partitioning in closed systems (EPICS) [6], and, more recently, the static headspace method [7–10]. The EPICS and static headspace methods both involve preparation of dilute aqueous solutions containing an organic compound and allowing it to partition into the air in contact with the solution in a closed vessel under temperature‐controlled conditions until thermodynamic equilibrium is reached.…”

Section: Introductionmentioning

confidence: 99%

Determination of Henry's law constants by equilibrium partitioning in a closed system using a new in situ optical absorbance method

Allen

Balcavage

Ramachandran

et al. 1998

Enviro Toxic and Chemistry

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A new method for measurement of thermodynamic Henry's law constants (H) is reported. In this method, the optical absorbance of a dilute aqueous solution containing an organic compound is followed with time as the compound partitions into the air above the solution in a sealed vessel. The change in optical absorbance (i.e., change in concentration) and the vapor to liquid volume ratio of the vessel are then used to calculate the value for H. The concentration of the organic compound in the aqueous and vapor phases need not be known. This method allows the approach to equilibrium to be observed in real time so that attainment of equilibrium is readily apparent. This method works particularly well for water‐soluble compounds having low vapor pressures. The applicability of this method is limited to compounds that exhibit significant optical absorbance in the ultraviolet and visible regions of the electromagnetic spectrum. Values for H and their temperature dependencies measured using this new method are reported for methacrolein, methyl vinyl ketone, benzaldehyde, and acetophenone. Values for H are also reported for benzene, toluene, and ethylbenzene at 298 K. All reported H data are compared with previously reported values.

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Section: Introductionmentioning

confidence: 99%

Determination of Henry's law constants by equilibrium partitioning in a closed system using a new in situ optical absorbance method

Allen

Balcavage

Ramachandran

et al. 1998

Enviro Toxic and Chemistry

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“…More information related to the critical data evaluation (the method used, primary data reported, estimated uncertainty, comments) is available in the online database at 4 Gibbs Energy of Hydration of Nitriles at 298.15 K and 0.1 MPa, Experimental and Group Contribution (GC) Values Δ vap G °Δ h G °ΔΔcompoundkJ·mol -1 kJ·mol -1 accepted value1st order GC valuekJ·mol -1 2nd order GC valuekJ·mol -1 acetonitrile 5.36 ± 0.05 a −9.02 k H , − 9.01 k H , 41 b −9.65 K D , −9.17 γ ∞ , 64 c −8.72 K D , −9.11 γ ∞ , 66 b −9.84 k H , 67 d −9.59 γ ∞ , −9.35 γ ∞ , − 9.10 γ ∞ , 70 e −8.72 K D , − 8.79 γ ∞ , 72 b −9.82 k H , 73 d −8.66 γ ∞ , 74 b , −9.10 γ ∞ , 75 f −8.81 k H 76 −9.04 ± 0.25 −8.57 −0.47 −9.04 0.00 propanenitrile 6.90 ± 0.10 a − 7.87 k H , 41 g −7.95 Sol, −7.23 Sol, 51 g −7.86 γ ∞ , −8.02 γ ∞ , −8.04 Sol, 68 g −7.96 Sol, 79 d −8.06 Sol, −8.11 k H 81 −7.91 ± 0.20 −7.87 −0.04 −7.90 −0.01 butanenitrile 9.00 ± 0.10 a −6.4 K D , −7.02 Sol, 51 d −7.25 γ ∞ , −7.14 γ ∞ , −7.16 Sol, −7.30 k H 81 −7.18 ± 0.30 −7.17 −0.01 −7.22 0.04 2-methylpropanenitrile 7.66 ± 0.15 a −5.91 Sol, 51 d −5.46 γ ∞ , −5.81 γ ∞ 69 −5.70 ± 0.30 −6.62 0.92 −5.70 0.00 pentanenitrile 11.46 ± 0.15 a −6.83 Sol, 51 d −6.48 γ ∞ , −6.55 γ ∞ , −6.05 Sol 84 −6.50±0.30 −6.47 −0.03 −6.54 0.04 hexanenitrile 14.02 ± 0.15 a − 6.02 γ ∞ , −6.90 Sol 60 −6.14 ± 0.60 −5.77 …”

Section: Data Compilationmentioning

confidence: 99%

Group Contribution Values for the Thermodynamic Functions of Hydration at 298.15 K, 0.1 MPa. 4. Aliphatic Nitriles and Dinitriles

2006

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A compilation of experimental values of the infinite dilution partial molar Gibbs energy, enthalpy, and heat capacity of hydration together with partial molar volumes in water at 298.15 K and 0.1 MPa is presented for aliphatic nitriles and dinitriles. These data are treated in the framework of the first-and second-order group additivity methods. Thermodynamic properties are determined for the first-order CN group and for the following secondorder groups: C-(CN)(C)(H) 2 , C-(CN)(C) 2 (H), and CN-(C). The relatively long-range dipole-dipole interactions of two terminal nitrile groups require additional corrections, {CN-(CH 2 ) 2 -CN} corr and {CN-(CH 2 ) 3 -CN} corr , for lower dinitriles. New experimental studies of aqueous branched mononitriles and lower dinitriles (particularly propanedinitrile) are required to expand the usefulness and accuracy of group contribution models for aqueous nitriles.

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“…The major application of Henry's law today is the determination of the atmospheric concentration of environmentally important organic compounds. Henry's law is usually used to calculate the gaseous concentration of a solute from the aqueous concentration (21). If the initial slope of the p͞X curve is zero within 5% or 10%, then Henry's law can be used within experimental error for many cases.…”

Section: Is Henry's Law Only a Limiting Law For Binary Solutions?mentioning

confidence: 99%

Henry's Law: A Retrospective

Rosenberg

Peticolas

2004

J. Chem. Educ.

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This article reviews the evolution of Henry's law from its original form as a description of the effect of pressure on the solubility of a gas through a description of the vapor pressure of a volatile solute in dilute solution to a basis of the standard state of a solute. We also relate Henry's law to the properties of regular solutions. We raise the question of whether Henry's law is applicable to any finite concentration and conclude that it is properly only a limiting law in the limit of infinite dilution.

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Air-Water Partitioning of Environmentally Important Organic Compounds: An Environmental Chemistry or Integrated Laboratory Experiment

Cited by 21 publications

References 9 publications

Determination of Henry's law constants by equilibrium partitioning in a closed system using a new in situ optical absorbance method

Determination of Henry's law constants by equilibrium partitioning in a closed system using a new in situ optical absorbance method

Group Contribution Values for the Thermodynamic Functions of Hydration at 298.15 K, 0.1 MPa. 4. Aliphatic Nitriles and Dinitriles

Henry's Law: A Retrospective

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