Ethane data

Fig. 2-10. Pressure-volume diagram of ethane. (Data from Brown et al., Natural Gasoline and the Volatile Hydrocarbons, NGAA, Tulsa, 1947.)...

In general, the data accuracy was surprisingly good. For example, while Deaton and Frost (1946, p. 13) specified that their pure ethane contained 2.1% propane and 0.8% methane, effects of those impurities may have counterbalanced each other those impurities were insufficient to cause the data to fall outside the line formed by other ethane data sets. On the other hand, the simple hydrate data of Hammerschmidt (1934) for propane and isobutane all appear to be outliers on such semilogarithmic plots, because they are at temperatures much too far above the upper quadruple (Q2) point. Obvious outlying data were excluded from this work less obvious outliers may be determined by inspection of the plots and subsequent numerical comparisons. The data, followed by the semilogarithmic plots... 

Figure 12 (a) Ti (p, T) data measured in fluoroform on the near critical isotherm (28°C), 2 K above Tc, and the calculated curve, which is scaled to match the data at the critical density, 7.56 mol/L. The fluoroform hard sphere diameter was adjusted since a good value at experimental temperatures is not available. A diameter of 3.28 A yielded the optimal fit. co is not adjustable. It is set equal to 150 cm-1, the value obtained in the fit of the ethane data. The theory does a very good job of reproducing the shape of the data with only the adjustment in the solvent size as a fitting parameter that affects the shape of the calculated curve, (b) Ti(p, T) data taken at 44°C, which is the equivalent increase in temperature above Tc as the higher temperature data taken in ethane (Fig. 10b). The theory curve is calculated using the same scaling factor, frequency, and solvent hard sphere diameter as at the lower temperature. Considering that there are no free parameters, the theory does an excellent job of reproducing the higher temperature data.

Figure 3. 1 Phase diagram for mixtures of methane and ethane. Data taken from a variety of sources.

Table III shows the effect of shifting furnace operation from propane fresh feed to ethane. Data are from Schutt and Zdonik (54). The reduction of propylene yield from ethane to negligible levels in favor of increased ethylene production cannot be done if a plant has propylene commitments. Because propylene requirements cannot be satisfied with ethane feed, Ericsson (14) has concluded that propane will continue to be the preferred feedstock to make ethylene. Actually, 85% of the U.S. ethylene plants are located in the Gulf Coast area so that they can obtain and operate on economical ethane and propane feeds. The need for propane pyrolysis has resulted in a renewal of experimental interest in this area, and in-depth studies have been made by Crynes and Albright (17) and by Buekens and Froment (7).

Figure 8. S2LV lines for several compounds in supercritical ethane. (Data from Ref. 31-33).

Values estimated by intrapolation from ethane data. Source Ref. 17. 

For tripalmitin, it should be noted that the CO2 and ethane data are not at the same temperature not at the same reduced temperature. The CO2 and propane at 429 K data are at similar reduced solvent temperatures and the ethane and propane at 436 K data are at similar reduced solvent temperatures. Tripalmitin is thus considerably more soluble in propane than in ethane or CO2. It should be recalled (See Figure 8) that significant scatter exists for the C02/tripalmitin data. Before an outcome regarding a comparison of the solubility of tripalmitin in CO2 and ethane can be given, issues relating to this scatter need to be resolved. The accuracy of the ethane/tripalmitin approximation also needs to be verified. In all likelihood, additional C02/tripalmitin as well as ethane/tripalmitin data need to be measured. 

FIGURE 6.9 Reduced descriptors for two- and four-carbon systems. Plotted are versus scaled via ethane data. The point for ethane molecule appears at 1,1- The error rs are established by o j and from regression analyses. 

It was shown in Chapter 6 that the contrasts among molecules are most acute concerning mutual information and energy dispersion. Following the same approach, reduced descriptors for the states can be constructed using ethane data for a baseline, for example ... 

FIGURE 7.9 Reduced descriptors for chemical reactants and products. Plotted are versus scaled via ethane data. 1,2, and 3 refer to the unimolecular reactions discussed in the text. Filled symbols denote the state points for reactants open symbols locate the state points of products. 

FIGU RE 7.11 Reduced descriptors for tautomers and structural isomers of C5H10O2. Plotted are versus scaled via ethane data. 1 refers to the tautomerization of 2,4-pentanedione. The two other state points in the figure derive from struetural isomers. 

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