Thermodynamic excess properties for ethanol-n-heptane

Ness, Hendrick C. Van; Soczek, C. A.; Kochar, Nand K.

doi:10.1021/je60034a015

Cited by 119 publications

(50 citation statements)

References 7 publications

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“…With decreasing alcohol concentration, the equilibrium shifts towards monomers and the number of hydrogenbonded OH groups decreases. This supposition is confirmed by non-symmetrical isotherms of excess molar enthalpies with maxima at the mole fraction of ethanol close to 0.35 [20]. Thus, the endothermic effect of breaking the hydrogen bonds manifests itself at rather low concentrations of the alcohol.…”

Section: Discussionmentioning

confidence: 75%

Thermodynamic and acoustic properties of binary mixtures of alcohols and alkanes. II. Density and heat capacity of (ethanol+n-heptane) under elevated pressures

Dzida

Marczak

2005

The Journal of Chemical Thermodynamics

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Section: Discussionmentioning

confidence: 75%

Thermodynamic and acoustic properties of binary mixtures of alcohols and alkanes. II. Density and heat capacity of (ethanol+n-heptane) under elevated pressures

Dzida

Marczak

2005

The Journal of Chemical Thermodynamics

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“…Several measurements of the VLE behavior at 0.1 MPa for ethanol + n-heptane are reported in the literature [18][19][20]. The VLE phase diagram at 0.1 MPa is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…1 revealing an azeotropic behavior. In this figure, the experimental data [18][19][20] are shown along with the VLE behavior obtained by the PC SAFT equation [21,22] using k ij = 0.0435, which was correlated to the experimental VLE data [18][19][20]. A bubble temperature calculation reveals that the overall average absolute deviation (AAD) between the reported temperatures [18][19][20] and the calculated values is 0.6 K, whereas the AAD between the experimental vapor mole fractions of ethanol [18][19][20] and the predicted values is 6.9%.…”

Section: Resultsmentioning

confidence: 99%

Comparative experimental and modeling studies of the viscosity behavior of ethanol+C7 hydrocarbon mixtures versus pressure and temperature

Zéberg-Mikkelsen

Watson

Baylaucq

et al. 2006

Fluid Phase Equilibria

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“…a s reported by Van Ness e t al. (6) and illustrated in Figure 1. These data are required for the calculation of the composition of the vapor phase.…”

Section: Applications To Thermodynamic Datamentioning

confidence: 99%

An extension of the spline fit technique and applications to thermodynamic data

Klaus

Ness

1967

AIChE Journal

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T h e spline fit technique i s extended to permit the smoothing of experimental doto. It i s applied to thermodynamic data which are otherwise difficult to treat.There is always a need for methods to smooth, interpolate, differentiate, or otherwise treat experimental data. Sometimes equations are available from theoretical considerations which contain a certain number of undetermined constants whose best values may be calculated from the experimental data. In other c a s e s empirical equations have come into u s e where experience has shown them to correlate adequately a certain kind of experimental data. A familiar example i s the use of the Antoine equation to correlate vapor pressure data a s a function of temperature (1). In the absence of either a theoretical or an empirical correlating equation, polynomials have frequently been used. Experience has shown that they often correlate experimental data very well. Moreover, if the polynomial coefficients are viewed a s the unknown quantities to be determined from experimental data, the fitting procedure is linear, a distinct computational advantage. There are a number of numerical procedures for this type of calculation.One of the most powerful is that due to Forsythe (2). This has been generalized and applied to various types of thermodynamic data (3).T o be acceptable, a representation should be reasonably low-ordered, correlate the data to within the experimental error, and introduce no unwarranted inflection points. The latter is particularly important if the data are to be differentiated. Unfortunately there are a number of instances where the search for an adequate polynomial representation of the complete s e t of data has been unsuccessful. Certain alcohol-hydrocarbon heat of mixing and vapor pressure data as a function of liquid mole fraction are of this type. The difficulty in representing these data seems to be related to the steepness of the required curves in one or more parts of the composition interval a s compared with other parts. THE SPLINE FIT TECHNIQUEOne way to circumvent these problems is to use the spline fit technique which i s discussed by Landis and Nilsen ( 4 ) . This method puts a different cubic between every two successive data points such that the curves p a s s exactly through each data point and that the first two derivatives of the curve on the right-hand side of a data point are equal, respectively, to the first two derivatives of the curve on the left-hand side of the data point, all derivatives evaluated a t the data point.Since some of the same equations apply in the extended method to be presented later, the derivations of the equations of the original method are summarized below.Since the curves in every interval* are cubics, the second derivative in a given interval is. linear; that is *The k'h interval in these derivations is taken t o b e Xk sx < X k + l , where xk is the independent variable for the kch data point,

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Thermodynamic excess properties for ethanol-n-heptane

Cited by 119 publications

References 7 publications

Thermodynamic and acoustic properties of binary mixtures of alcohols and alkanes. II. Density and heat capacity of (ethanol+n-heptane) under elevated pressures

Thermodynamic and acoustic properties of binary mixtures of alcohols and alkanes. II. Density and heat capacity of (ethanol+n-heptane) under elevated pressures

Comparative experimental and modeling studies of the viscosity behavior of ethanol+C7 hydrocarbon mixtures versus pressure and temperature

An extension of the spline fit technique and applications to thermodynamic data

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