Vapor‐liquid and liquid‐liquid vapor phase behavior of the carbon monoxide‐propane and the carbon monoxide‐ethane systems

Trust, D. B.; Kurata, Fred

doi:10.1002/aic.690170232

Cited by 25 publications

(4 citation statements)

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“…Assuming enhanced solubility of R143a in C 6 H 14 O due to its dipole moment therefore seems to be insufficient. Figure 5 further indicates that for the C 6 H 14 O-based systems with R143a or SF 6 , a liquid−liquid phase boundary has been observed in the DLS setup at the largest p studied except for C 6 H 14 O/SF 6 at T = 348 K. For C 6 H 14 O/R143a at T = 348 K and for C 6 H 14 O/SF 6 at T = 323 K, this observation was made at experimental conditions slightly exceeding the critical temperatures of pure R143a, T c = 345.86 K, and of pure SF 6 , T c = 318.72 K. The phenomenon of VLLE occurring for binary systems slightly above T c of the component with the lower boiling point has also been reported in the literature for, e.g., ethene/nitrogen, 56 ethane/nitrogen 56,57 and propane/ carbon monoxide, 58 (n-hexanol, n-octanol, or n-decanol)/ CO 2 59 and (ethanol, n-propanol, n-butanol, or n-pentanol)/ ethane, 60 where no explanation of this specific behavior has been provided by the authors. While in the observed VLLE of C 6 H 14 O-based systems, the SF 6 -rich phase was always the lower liquid phase, this only holds for T = 303 K for the R143a-rich liquid phase.…”

Section: Solubilities and Phase Equilibrium Informationsupporting

confidence: 67%

Solubility and Liquid Density of Binary Mixtures of n-Hexane or 1-Hexanol with Krypton, Sulfur Hexafluoride, or R143a

et al. 2023

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Within the present study, the solubility, phase behavior, and liquid density of binary systems consisting of nhexane (C 6 H 14 ) or 1-hexanol (C 6 H 14 O) and krypton (Kr), sulfur hexafluoride (SF 6 ), or the refrigerant 1,1,1-trifluoroethane (R143a) are investigated at temperatures between 303 and 348 K and pressures up to 14 MPa. For this, the isochoric-saturation method featuring in-line density measurements of the saturated liquid phase is applied in combination with Raman spectroscopy. The latter is calibrated for the systems comprising SF 6 and R143a with the experimentally measured solubility data to allow for the determination of the liquid-phase composition of these binary mixtures on other setups solely by the evaluation of Raman spectra. This is performed in this study on a second setup where the Raman spectra obtained especially in the SF 6 -and R143-rich regimes complement the characterization of the phase behavior. The solubility in C 6 H 14 O was found to be distinctly lower than in C 6 H 14 for all gases. Furthermore, a liquid−liquid phase separation was observed for C 6 H 14 O/SF 6 and C 6 H 14 O/R143a at nearly all investigated temperatures. These and further results are discussed in connection with the molecular properties of the mixture components.

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Section: Solubilities and Phase Equilibrium Informationsupporting

confidence: 67%

Solubility and Liquid Density of Binary Mixtures of n-Hexane or 1-Hexanol with Krypton, Sulfur Hexafluoride, or R143a

et al. 2023

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“…x CO = 0.198 mol/mol, where experimental vapor pressure and dew point carbon monoxide mole fraction are 5.614 MPa and 0.8065 mol/mol [49]. To eliminate the influence of experimental scatter, the pressure -composition data were smoothed [50].…”

Section: Case Studymentioning

confidence: 99%

Unlike Lennard–Jones parameters for vapor–liquid equilibria

Schnabel

Vrabec

Hasse

2007

Journal of Molecular Liquids

110

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The influence of the unlike Lennard-Jones (LJ) parameters on vapor-liquid equilibria of mixtures is investigated and the performance of eleven combining rules is assessed. In the first part of the work, the influence of the unlike LJ size and energy parameter on vapor pressure, bubble density and dew point composition is systematically studied for the mixtures CO+C 2 H 6 and N 2 +C 3 H 6 , respectively. It is found that mixture vapor pressure depends strongly both on the size and the energy parameter whereas the bubble density depends mostly on the size parameter and the dew point composition is rather insensitive to both parameters. In preceding work, unlike LJ parameters were adjusted to experimental binary vapor-liquid equilibria for 44 real mixtures. On the basis of these results, in the second part of the work eleven combining rules are assessed regarding their predictive power. A comparison with the adjusted unlike LJ parameters determined from the fit shows that none of the eleven combining rules yields appropriate parameters in general. To obtain an accurate mixture model, the unlike dispersive interaction should therefore be adjusted to experimental binary data. The results from the present work indicate that it is sufficient to use the Lorenz rule for the unlike LJ size parameter and to fit the unlike LJ energy parameter to the vapor pressure.In molecular simulations of a binary mixture A+B with pairwise additive potentials, three different interactions occur: two like interactions between molecules of the same type A-A and B-B, which are fully defined by the pure component models, and the unlike interaction between molecules of different type A-B. In mixtures consisting of polar molecules, the electrostatic part of the unlike interaction is fully determined by the laws of electrostatics. However, there is no rigorous physical framework that yields reliable unlike repulsion and dispersion parameters like the Lennard-Jones (LJ) parameters studied in the present work. For finding these parameters, combining rules were developed in the past based on physical and mathematical intuition or on empirical approaches. Eleven of these combining rules were investigated in the present work.These combining rules rely soley on pure component data, namely the LJ parameters and, in some cases, additionally the polarizablility α or the ionization potential I. Other combining rules, that are not discussed in this work, also employ dispersion force coefficients [1, 2, 3], diamagnetic susceptibility [4,5] or effective transition energies [6,7].Another approach for obtaining unlike LJ parameters is to adjust them directly to experimental binary data, for which a single data point may in principle be sufficient. Kohler et al. [8] fitted both unlike LJ parameters to experimental second virial coefficients of binary mixtures.Following this approach, Möller et al.[9] developed a method for adjusting the unlike LJ size and energy parameters to experimental excess volumes and enthalpies. Their investigations showed that the un...

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“…We have varied both the temperature and the concentration of CO in scCH 4 solution, and accordingly, under all measured conditions, both sets of bands decay at the same rate. The observed rate constant for the decay of 7 and 8 increased § The second-order rate constant in liqC2H6 was calculated by assuming that all of the CO was soluble (39). Extrapolation of the second-order rate constant obtained in scC2H6, where there is complete miscibility between CO and C2H6 at 298 K, leads to an equivalent kCO value within the experimental error.…”

mentioning

confidence: 99%

Time-resolved infrared (TRIR) study on the formation and reactivity of organometallic methane and ethane complexes in room temperature solution

Cowan

Portius

Kawanami

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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We have used fast time-resolved infrared spectroscopy to characterize a series of organometallic methane and ethane complexes in solution at room temperature: W(CO)5(CH4) and M( 5 OC5R5)(CO)2(L) [where M ‫؍‬ Mn or Re, R ‫؍‬ H or CH3 (Re only); and L ‫؍‬ CH4 or C 2 H 6 ]. In all cases, the methane complexes are found to be short-lived and significantly more reactive than the analogous nheptane complexes. Re(Cp)(CO)2(CH4) and Re(Cp*)(CO)2(L) [Cp* ‫؍‬ 5 OC5(CH3)5 and L ‫؍‬ CH4, C2H6] were found to be in rapid equilibrium with the alkyl hydride complexes. In the presence of CO, both alkane and alkyl hydride complexes decay at the same rate. We have used picosecond time-resolved infrared spectroscopy to directly monitor the photolysis of Re(Cp*)(CO)3 in scCH4 and demonstrated that the initially generated Re(Cp*)(CO)2(CH4) forms an equilibrium mixture of Re(Cp*) ( T here is considerable interest in sigma-bonded organometallic alkane complexes, particularly since they have been identified as key intermediates in the transition metal-mediated COH activation process (1-3). Although such complexes generally are very short-lived intermediates (4), they have been known for over 30 years. Early experiments involved the photolysis of complexes such as Cr(CO) 6 and Fe(CO) 5 to generate the unstable intermediates Cr(CO) 5 or Fe(CO) 4 in low-temperature matrices, where coordination to cocondensed CH 4 results in the formation of Cr(CO) 5 (CH 4 ) and Fe(CO) 5 (CH 4 ) (5, 6).Flash photolysis experiments have demonstrated that the photolysis of Cr(CO) 6 in cyclohexane solution at room temperature forms Cr(CO) 5 (cyclohexane) (7). Subsequently, several examples of alkane complexes in solution have been reported, and studies on the mechanism of the COH activation process have clearly demonstrated the role of these complexes in oxidative addition reactions (1,8,9). Time-resolved infrared (TRIR) spectroscopy has proved to be a powerful tool for the study of metal carbonyl alkane complexes. Their reactivity decreases on going both across and down groups 5, 6, and 7 (10-12), and these observations led to the identification of a very long-lived alkane complex, Re(Cp)(CO) 2 (nheptane) (Cp ϭ 5 OC 5 H 5 ), which has a lifetime of Ϸ25 ms at room temperature (13). The relative stability of Re(Cp)(CO) 2 (alkane) complexes allowed Re(Cp)(CO) 2 (C 5 H 10 ) to be observed at 180 K by NMR spectroscopy (14), and subsequent NMR studies have been carried out to determine the binding modes of a series of related alkanes to the Re(CpЈ)(CO) 2 moiety (15, 16).The activation of methane is of particular interest because of the potential of using this abundant hydrocarbon as both an energy source and chemical feedstock (17). Organometallic methane complexes have been characterized in low-temperature matrix isolation experiments (5,6,18). In solution, the existence of methane complexes has been inferred by examining product ratios and from the rates of COH activation and reductive elimination reactions in isotopic labeling experiments (19).The lifetime of the...

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Vapor‐liquid and liquid‐liquid vapor phase behavior of the carbon monoxide‐propane and the carbon monoxide‐ethane systems

Cited by 25 publications

References 5 publications

Solubility and Liquid Density of Binary Mixtures of n-Hexane or 1-Hexanol with Krypton, Sulfur Hexafluoride, or R143a

Solubility and Liquid Density of Binary Mixtures of n-Hexane or 1-Hexanol with Krypton, Sulfur Hexafluoride, or R143a

Unlike Lennard–Jones parameters for vapor–liquid equilibria

Time-resolved infrared (TRIR) study on the formation and reactivity of organometallic methane and ethane complexes in room temperature solution

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