Virial ethylene

A3 AIBN c Cp DLS DLVO DSC EO GMA HS-DSC KPS LCST Osmotic third virial coefficient 2,2 -Azobis(isobutyronitrile) Polymer concentration Partial heat capacity Dynamic light scattering Derjaguin-Landau-Verwey-Overbeek Differential scanning calorimetry Ethylene oxide Glycidylmethacrylate High-sensitivity differential scanning calorimetry Potassium persulphate Lower critical solution temperature... 

The heats of adsorption of ethane and ethylene at zero coverage are presented in Table II. These heats are obtained by means of the virial equations (12). The heats of adsorption of ethylene exceed those of ethane because of specific interactions (7, 8). As the dimensions and polarizability of the ethane and ethylene molecules are similar, the energy of nonspecific interaction of these molecules with the zeolite surface must be approximately equal (6). Therefore, the differences of the heats of adsorption of ethane and ethylene, aQ, on the same zeolite is considered to be approximately the contribution of the specific interaction of the TT-bonds of ethylene with the corresponding cation. The values of these differences for all systems studied are presented also in Table II. 

State-of-the-Art Determination of the Second Virial Coefficient of Ethylene for Temperatures from 0° to 175 °C... 

Values of the second virial coefficient of ethylene for temperatures between 0° and 175°C have been determined to an estimated accuracy of 0.2 cm3/mol or less from low-pressure Burnett PVT measurements. Our values, from —167 to —52 cm3/mol, agree within an average of 0.2 cm3/mol with those recently obtained by Douslin and Harrison from a distinctly different experiment. This close agreement reflects the current state of the art for the determination of second virial coefficient values. The data and error analysis of the Burnett method are discussed. 

The results themselves have a subtlety associated with their interpretation owing to the presence of the volume-ratio parameter and, optionally, the initial density parameter. The Burnett equations have more flexibility to fit Burnett data than only a density series to PVT data. The statistical uncertainties reflect the quality of the experimental data relative to the particular model used to describe the experiment. The estimation of accuracy for Burnett results is necessarily somewhat subjective since the effect of systematic errors on parameter values is not explicit in nonlinear equations, such as the Burnett equations. Accuracy, however, can be estimated from a study of the effects of systematic errors in computer model calculations and from the magnitude of the change in the volume-ratio value determined with nonideal and nearly ideal gases. For these reasons, we include such information along with our virial coefficient results for ethylene. 

The highest power of the series terms chosen to define each isotherm reflected the extent of the nonideality. For the ethylene isotherms, a cubic series was used for temperatures from 0° to 25°C and a quadratic series was used for temperatures from 75° to 175°C. At 50°C, a quadratic series as well as a cubic series were used. For the helium isotherms, a quadratic series was used with the virial coefficient of the quadratic term treated as a constant obtained from published values rather than as a parameter. The other parameters were evaluated more accurately with the quadratic coefficient treated as a constant rather than as a parameter since the contribution of this term was so small for our range of pressures. The term functioned only as a virial remainder. In the helium data analyses, the parameters were common to all of the data. For the ethylene data analyses, only the virial coefficient parameters were common to all of the data an initial density parameter was required for each sequence... 

The effects of systematic errors are best studied by analyses of accurate Burnett data with superimposed simulated errors. For a relative pressure offset of 0.003%, which is comparable with the accuracy of piston gauges, the ethylene second virial coefficient of —167 cm3/mol changes only by 0.02 cm3/mol. Thus, this type of error is largely cancelled in the Burnett method. An offset in N of 11 ppm, which is comparable with the N variation we expect, changes the same second virial coefficient by 0.1 cm3/mol. Errors resulting from truncation of the series... 

In Figure 5, we present a comparison of our preferred values for the ethylene second virial coefficient with comparable state of the art results obtained by Douslin and Harrison (2). The experimental method and data analysis used by Douslin are independent from ours. In Douslin s experiment, all of the variables required for the calculation of the compressibility factor are measured, whereas in the Burnett method only two variables are measured. Aslo, in this experiment the same sample of gas is retained for the entire experiment in the Burnett isothermal method, the sample is changed for each sequence of measurements. Furthermore,... 

Figure 5. Ethylene second virial coefficient comparison. AB2=B2 (Dous-lin) — B2 (this chapter) (%), Douslins graphical value (O), least-squares value from Douslins data.

Fig, 16> Virial coefficient of ethylene, a) Solid curve calculated from experimental results of l f. experimental data Ref. b) Comparison of data from Ref. and Ref. y with the smooth curve of 16a). (Reproduced by permission from Mehl and Moldover... 

In their study of association in ammonia + acetylene mixtures, Cheh, O Connell, and Prausnitz calculated the physical contribution to B12 from potentials that included hard-core as well as multipole interactions. The existence of vapour-phase complexes of ethylene with ammonia and methanol and of methanol with pentane has been inferred from virial coefficient data. King and co-workers have obtained association constants for COj with naphthalene, methanol, ethanol, and diethyl ether, and for HgO with CO2 and... 

Calculate the molar volume of ethylene at 40 °C, 90 bar, using the (a) ideal-gas law, (b) the truncated virial equation, and (c) the Pitzer correlation with the Lee-Kesler values for Zc°>, Z ). 

A container with a volume of V = 0.1 is filled with m = 10 kg ethylene at a temperature of T = 300 K. What will be the pressure and compressibility factor of the gas. Use the virial equation truncated after the second virial coefficient and the Peng-Robinson equation of state to describe the PVT-behavior. (virial coefficient B = -138 cm /mol, all other properties are given in Appendix A). 

GA2 Gaube, J., Pfennig, A., and Stirmpf, M., Thermodynamics of aqueous poly(ethylene glycol)-dextran two-phase systems using the consistent osmotic virial equation, Fluid Phase Equil, 83, 365, 1993. 

As the core of an ethylene molecule C2H4 we choose a thin rod connecting two carbon atoms with length I = 1.33 A. The choice of a rod core may be reasonable because of the it electrons and because of the fact that each molecule in an ethylene crystal can rotate about the CC bond. The values of po nd Uq determined from the second virial coefficient are... 

Second virial coefficient of poly(butylene oxide-b-ethylene oxide-b-butylene oxide)... 

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