Ethane boiling point

Murray, J. S., P. Lane, and P. Politzer. 1995b. Special Relationships of Fluorinated Methane/Ethane Boiling Points and Heats of Vaporization to Molecular Properties. J. Mol. Struct. (Theochem) 342, 15. 

Ethylene adsorption at room temperature is rapid and reversible. Even after prolonged exposure to the catalyst, the ethylene is recoverable as such by brief evacuation (10). The isotherms are nonlinear and show some evidence of saturation at 0.5-0.6 cm3/gm, a value roughly five times that of the type I hydrogen. Since the adsorption is quite weak, it would seem that this adsorption is, in part, physical adsorption. To investigate this possibility, adsorption of ethylene (boiling point — 104°C) was compared to that of ethane (boiling point — 89°C) (IS). By traditional criteria physical adsorption of ethane should be greater than that of ethylene, and the comparison of the relative adsorption should let us assay what fraction of the ethylene adsorption is physical. 

The amount of ethylene is limited because it is necessary to restrict the amount of unsaturated components so as to avoid the formation of deposits caused by the polymerization of the olefin(s). In addition, ethylene [boiling point —104°C (—155°F)] is more volatile than ethane [boiling point —88°C (—127°F)], and therefore a product with a substantial proportion of ethylene will have a higher vapor pressure and volatility than one that is predominantly ethane. Butadiene is also undesirable because it may also produce polymeric products that form deposits and cause blockage of lines. 

For an actual determination, first place in J some stable liquid the boiling-point of which is at least 50 above that of the organic liquid the pour density of which is to be measured. This difference in boiling-point is important, because it is essential that the organic liquid, when nbsequently dropped into the bottom of T, should volatilise rapidly nd so push out an equivalent volume of air before the organic vapour can diffuse up the tube T and possibly condense in the cooler ttppcr portion of the tube. Suitable liquids for use in the jacket are ter, chlorobenzene (132°), rym-tetrachloro-ethane (147 ), P ... 

ElexibiHty allows the operator to pick and choose the most attractive feedstock available at a given point in time. The steam-cracking process produces not only ethylene, but other products as weU, such as propylene, butadiene, butylenes (a mixture of monounsaturated C-4 hydrocarbons), aromatics, etc. With ethane feedstock, only minimal quantities of other products ate produced. As the feedstocks become heavier (ie, as measured by higher molecular weights and boiling points), increasing quantities of other products are produced. The values of these other coproduced products affect the economic attractiveness and hence the choice of feedstock. 

The only method utilized commercially is vapor-phase nitration of propane, although methane (70), ethane, and butane also can be nitrated quite readily. The data in Table 5 show the typical distribution of nitroparaffins obtained from the nitration of propane with nitric acid at different temperatures (71). Nitrogen dioxide can be used for nitration, but its low boiling point (21°C) limits its effectiveness, except at increased pressure. Nitrogen pentoxide is a powerful nitrating agent for alkanes however, it is expensive and often gives polynitrated products. 

It is important to note that simulated distillation does not always separate hydrocarbons in the order of their boiling point. For example, high-boihng multiple-ring-type compounds may be eluted earher than normal paraffins (used as the calibration standard) of the same boiling point. Gas chromatography is also used in the ASTM D 2427 test method to determine quantitatively ethane through pentane hydrocarbons. 

Methane is the main constituent, with a boiling point of 119 K (—245°F). Ethane, with a boiling point of 184 K (—128°F) may be present in amounts up to 10 percent propane, with a boiling point of 231 K (—44°F), up to 3 percent. Butane, pentane, hexane, heptane, and octane may also be present. Physical properties of these hydrocarbons are given in Sec. 2. 

Table 4. Boiling Points and Dipole Moments of Methanes and Ethanes [17,18]...

Methanol has a considerably higher boiling point than its alkane relatives, methane and ethane, consistent with significant intermolecular forces. Ammonia dissolves readily in acetone, also consistent with significant intermolecular forces. 

C14-0051. Table lists molar enthalpies of vaporization of several substances. Calculate the molar entropy of vaporization at its normal boiling point for each of the following (a) molecular oxygen (b) ethane (c) benzene and (d) mercury. 

C14-0115. The normal boiling point of ethane is 184 K, at which A W Determine... 

As a general rule difficult or expensive separations should be performed last, since by that time less total material will be involved. Consider Table 4-1, which gives the product mix obtained in a cracking furnace of an ethylene plant and the normal boiling points of the compounds. Suppose it is desired to separate the six groups listed in the table using distillation. The separation of ethylene from ethane and propylene from propane will be the most difficult because they have the smallest boiling-point differences. Therefore, these steps should be performed last. 

Dinitro-2-butene may be prepared from 1-chloro-l-nitro-ethane by the same procedure, in 30% yield. The compound melts at 28-28.5° and has a boiling point of 135°/11 mm. Commercially available 1-chloro-l-nitroethane contains about 10% 1,1-dichloro-l-nitro-ethane and 2-chloro-2-nitropropane which cannot be separated by distillation, but these impurities do not interfere with the preparation. Distillation of 2,3-dinitro-2-butene behind safety glass in a nitrogen atmosphere is advisable. The submitters, in preparing this compound, have had one explosion over a period of ten years. 

About half the propane produced annually in the U.S. is used as a domestic and industrial fuel. When it is used as a fuel, propane is not separated from the related compounds, butane, ethane, and propylene. Butane, with boiling point -0.5 °C (31.1 °F), however, reduces somewhat the rate of evaporation of the liquid mixture. Propane forms a solid hydrate at low temperatures, and this causes great inconvenience when a blockage occurs in a natural-gas line. Propane is used also as so-called bottled gas, as a motor fuel, as a refrigerant, as a low-temperature solvent, and as a source of propylene and ethylene. 

A molecule with a greater number of carbon atoms usually has a higher boiling point than the same type of molecule with fewer carbon atoms. For example, hexane, CH3CH2CH2CH2CH2CH3 has a higher boiling point than ethane, CH3CH3. 

Acetaldehyde (ethanal), CH3CHO, is a polar molecule that has a boiling point of 20°C. Propane, on the other hand, is a non-polar molecule of similar size, number of electrons, and molar mass. The boiling point of propane, CH3CH2CH3, is —42°C. Use the concept of dipole-dipole forces to explain these property differences. 

Let us try to extrapolate this correlation to the available experimental data on some of the two-carbon HCFCs, based on ethane instead of methane, which is shown in table 5.12. There are new considerations, as tetrafluoroethane can have two different forms one with three fluorine atoms on one carbon and one fluorine atom on the other carbon, and the other with two fluorine atoms on each carbon. Nevertheless, the boiling points of the 19 substances satisfy the correlation formula of... 

Fig. 1 includes points for ethane and propane at 298 K for which Gfi = 0.94 and 0.43 ions/100 eV, respectively [16]. The electron mobilities for these liquids at this temperature are quite high. At even higher temperatures, in the supercritical fluid, Gfi and for ethane and propane are still higher [20,21]. On the other hand, at low temperatures near the boiling points, the yields of free ions as well as the mobilities in these liquids are quite low (Gfi = 0.16 for ethane for example), and points for these liquids then would be on the left side of the figure. 

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