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Volumn 113, Issue 40, 2009, Pages 13291-13299

Solvation structures of cis- and tran-l,2-dichloroethylene in supercritical CO2 investigatec by raman spectroscopy and attractive energy calculations

Author keywords

[No Author keywords available]

Indexed keywords

ATMOSPHERIC TEMPERATURE; CARBON DIOXIDE; RAMAN SCATTERING; RAMAN SPECTROSCOPY; SCHEMATIC DIAGRAMS; SOLVATION; SUPERCRITICAL FLUID EXTRACTION;

EID: 70349690568     PISSN: 15206106     EISSN: None     Source Type: Journal    
DOI: 10.1021/jp903240v     Document Type: Article
Times cited : (14)

References (74)
  • 40
    • 84906407110 scopus 로고    scopus 로고
    • The resolution of this Raman spectrometer is less than 0.8 cm-1 at full width at half maximum at high resolution conditions
    • The resolution of this Raman spectrometer is less than 0.8 cm-1 at full width at half maximum at high resolution conditions.
  • 43
    • 84906392376 scopus 로고    scopus 로고
    • Note
    • Almost studies on supercritical solutions have been performed using solutions of saturated or fixed molar concentrations. In these experimental conditions, solute mole fraction changes by fluid density, because the solubility of solute and number density of solvent molecules change depending on fluid density. On the other hand, the mole fraction of solute molecule was set to be constant in the present study, and the density dependence was investigated under the fixed mole fraction. That is, the Raman spectra were measured at fixed mole fractions of solute and solvent molecules in all densities, temperatures, and both solute molecules of cis- and trans-isomers.
  • 46
    • 84906392377 scopus 로고    scopus 로고
    • Note
    • The analysis based on the perturbed hard-sphere theory was conducted in Raman spectroscopic studies of some neat supercritical fluids in refs 33-35, 47, and 48 and supercritical solutions in refs 21 and 38 and conducted in infrared spectroscopic studies of supercritical solutions in refs 49 and 50.
  • 55
    • 84906378647 scopus 로고    scopus 로고
    • The values of attractive shifts were listed in Supporting Information Tables S1 and S2
    • The values of attractive shifts were listed in Supporting Information Tables S1 and S2.
  • 56
    • 84906407107 scopus 로고    scopus 로고
    • According to the perturbed hard-sphere analysis, the repulsive shift is not zero but the nonzero value at the density=0. This is indicated by the following equation. That is, eq 2 at density=0 brings δvR/v0=C1 exp(O)+C2 exp(O)-C3 exp(O)=Q+C2-C3≢0
    • According to the perturbed hard-sphere analysis, the repulsive shift is not zero but the nonzero value at the density=0. This is indicated by the following equation. That is, eq 2 at density=0 brings δvR/v0=C1 exp(O)+C2 exp(O)-C3 exp(O)=Q+C2-C3≢0.
  • 62
    • 84906407108 scopus 로고    scopus 로고
    • Note
    • In the pseudodiatomic approximation, (∂αo/∂QδQ and (∂μ/∂Q)δQ can be expressed by (∂α0/∂r)Ar and (∂μ0/∂r)δr, where Ar is given by δr ≃-(3/2) hcvoglf2.571 The term h is the Planck constant, and c is the speed of light in vacuum. ∂μ0/∂Q is given by ∂μ/∂Q =(3c2μredA/πN) 1/2, 63 where N, A, and μred are the Avogadro's number, integrated absorption coefficient, and reduced mass obtained from v0 ≃(k//μred)1/2/2π. Parameters required for calculations are listed in Table 2. Since trans-C2H2Cl2 and CO2 molecules do not possess a permanent electric dipole moment, eq 4 can be simplified by writing CA=CA,dis+ CA,DID+CA-D-Q for cis-C2H2Cl2, and CA=CA,dis for trans-C2H2Cl2.
  • 64
    • 84906364344 scopus 로고    scopus 로고
    • Note
    • 60
  • 66
    • 84906407109 scopus 로고    scopus 로고
    • Note
    • When the anisotropic shifts are averaged by θ and ø, the anisotropic shifts become the isotropic shift.
  • 67
    • 84906407105 scopus 로고    scopus 로고
    • Note
    • The value of CA is obtained from the summation of eqs 9-11, whose equations are functions of angles, θ0, θS, øo, and øs. One can obtain the CA value as a function of an angle by fixing the other angles.
  • 68
    • 84906378645 scopus 로고    scopus 로고
    • Note
    • In calculation of anisotropic attractive shift, the radial distance between solute and solvent molecules is fixed and is used as the sum of radii of solute and solvent molecules that are in contact. This idea is based on the model used in refs 49, 50, and 57 and is applied to the present analysis. As for the orientation, the anisotropic attractive shift is calculated by changing each angle.
  • 69
    • 84906392373 scopus 로고    scopus 로고
    • Note
    • As shown in Figure 7, the slope of attractive shifts changes slightly by the density. According to our estimation, the difference of slopes in the present density range is within 10%. Thus, we approximate the obtained data as linear density dependence.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.