Pentane vapor pressures

Distillation is used to prepare 99 percent pure products from a mixture of -butane and n-pentane. Vapor pressures taken from Perry s Handbook are given below. 

The ICC classifies all three pentanes as flammable Hquids and requires that they be affixed with a red label for shipping. Because of their high vapor pressures, n- and isopentane are transported in heavy-walled dmms and neo-pentanes are transported in cylinders (see Packaging containers and INDUSTRIAL MATERIALS). 

The first step in a gas processing plant is to separate the components that are to be recovered from the gas into an NGL stream. It may then be desirable to fractionate the NGL stream into various liquefied petroleum gas (LPG) components of ethane, propane, iso-butane, or normal-butane. The LPG products are defined by their vapor pressure and must meet certain criteria as shown in Table 9-1. The unfractionated natural gas liquids product (NGL) is defined by the properties in Table 9-2. NGL is made up principally of pentanes and heavier hydrocarbons although it may contain some butanes and very small amounts of propane. It cannot contain heavy components that boil at more than 375°F. 

The de-butanizer works in a similar manner. The upstream tower (depropanizer) determines the maximum vapor pressure of the butane product. If the concentration of propane-minus is too large in the inlet stream, the vapor pressure of the butane overheads will be too high. Similarly, the concentration of pentanes-plus in the butane will depend upon the... 

Pentane is a liquid with a vapor pressure of 512 Torr at 25°C at the same temperature, the vapor pressure of hexane is only 151 Torr. What composition must the liquid phase have if the gas-phase composition is to have equal partial pressures of pentane and hexane ... 

Which of the following liquids is expected to have the highest vapor pressure at 0°C octane, CHjfCHil CH, pentane, Cl I i(CH2)10 I, or neopentane, 2,2-dimethylpropane, C(CH3)4 Justify your answer. 

Reported vapor pressures of n-pentane at various temperatures and the coefficients for the vapor pressure ... 

FIGURE 2.1.1.1.8.2 Logarith m of vapor pressure versus reciprocal temperature for n-pentane. 

Mills, W.B., Dean, J.D., Porcella, D.B., Gherini, S.A., Hudson, R.J.M., Frick, W.E., Rupp, G.L., Bowie, G.L. (1982) Water Quality Assessment A Screening Procedure for Toxic and Conventional Pollutants. Part 1, U.S. EPA, EPA-600/6-82-004a. Mokbel, I., Rauzy, E., Loiseleur, H., Berro, C., Jose, J. (1995) Vapor pressures of 12 alkylcyclohexanes, cyclopentane, butylcyclo-pentane and frara -decahydronaphthalene down to 0.5 Pa. Experimental results, correlation and prediction by an equation of state. Fluid Phase Equil. 108, 103-120. 

Willingham, C.B., Taylor, W.J., Pignocco, J.M., Rossini, F.D. (1945) Vapor pressure and boiling points of some paraffin, alkylcyclo-pentane, alkylcyclohexane, and alkylbenzene hydrocarbons. J. Res. Natl. Bur. Std. 34, 219-244. 

A solution of pentane, C5Hi2, in carbon tetrachloride, CCI4, is nearly ideal. The vapor pressure of pentane is 450 mm Hg at 20°C, and the vapor pressure of carbon tetrachloride is 87 mm Hg at this temperature. What is the mole fraction of carbon tetrachloride in the vapor over an equimolar solution of these two liquids ... 

This material may be further purified (m.p. 99.5-100.0°) by recrystallization from pentane or methanol, or by sublimation at 85° (60 mm.). Owing to the unusually high vapor pressure of this product, large losses may be encountered on recrystallization or sublimation unless due care is exercised. 

Reid vapor pressure is measured at 100°F (37.8°C) and is used to help ensure that gasoline will vaporize adequately and ignite within the combustion chamber of an engine. Vapor pressure is provided by volatile gasoline components such as dissolved butane gas and the presence of pentanes, hexanes, heptanes, and benzene. 

The vapor pressure, p, of a solvent at 25°C is an important quantity and varies considerably among common solvents, some being very volatile (n-pentane and diethyl ether) whereas others are quite nonvolatile (n-hexadecane and dibutyl phthalate). 

Use the linear form of the Langmuir equation to evaluate (n/w)sat and K for the adsorption of pentane on carbon black from the higher pressure values in the following data. Use the ratio p/p0 rather than p only to normalize pressures relative to the equilibrium vapor pressure of pentane at different temperatures. (All pressures are in torr.)... 

It can be seen that while this particular crude oil contains over 95t by volume pentanes and heavier, these constituents only contribute about 201 to the vapor pressure. Most of the vapor pressure of this oil is contributed by the propane and butanes, since it contains very little methane and ethane. This oil stream is the product of an extremely selective separation process. Crude oil streams, unless they have "weathered" in an open tank for some period of time,... 

The vapor pressure of a light component at a given temperature, divided by the vapor pressure of a heavier component at the same temperature, is called the relative volatility. For practice, calculate the relative volatility of isobutanes and normal pentane at 140°F (answer 4.0). Next, calculate their relative volatility at 110°F (answer 4.9).1... 

At atmospheric pressure, all mixtures of these components will be gas. See Figure 2-28(1). The temperature is well above the critical temperature of methane, and atmospheric pressure is well below the vapor pressures of propane and n-pentane at 160°F. 

Consider a pressure above the vapor pressure of n-pentane and below vapor pressure of propane, for instance, 200 psia. See dot 2 on Figure 2-29 and Figure 2-28(2). All mixtures of methane and propane are gas. Both the methane-n-pentane binary and the propane-n-pentane binary are in their two-phase regions. Their bubble-point and dew-point compositions appear along the sides of the ternary diagram as the ends of the bubble-point and dew-point lines of the ternary mixtures. 

Fig. 2-29. Vapor pressures of methane, propane, and n-pentane with critical loci of binary mixtures. (The numbered points correspond to the diagram numbers on Figure 2-28.)...

At pressures above the vapor pressure of propane and less than the critical locus of mixtures of methane and n-pentane, for instance 500 psia, dot 4, the methane-propane and methane-n-pentane binaries exhibit two-phase behavior, and propane-n-pentane mixtures are all liquid. Thus the saturation envelope appears as in Figure 2-28 (4). 

G. Temperature Determinations. In vacuum line work it is frequently necessary to measure low temperatures. While the mercury-in-glass thermometer is convenient, it does not extend below the freezing point of mercury, — 38.9°. Pentane-in-glass thermometers have a similar convenience and may be used down to about — 150°C, but they are only useful for rough work (an error of 5°C is common). For more precise determinations, a calibrated thermocouple or thermistor, or a vapor pressure thermometer, is useful. 

M85 or E85 created using this gasoline will probably be between 62 kPa (9 psi) and 69 kPa (10 psi). To compensate, the gasoline used to produce M85 or E85 will contain additional butane and/or pentanes to counteract the damping effect of the low vapor pressure of methanol and ethanol. 

The accuracy of the pressure and temperature measurements was verified by measuring the vapor pressure curves and critical points for pentane and for toluene. Vapor pressures were measured by observing the formation of a liquid phase as pentane or toluene was injected into the constant-volume view cell under isothermal conditions. The observation of critical opalescence was used to determine the critical point. The measured vapor pressures and critical points are given in Table I. Vapor pressures deviate from... 

Table I. Measured Vapor Pressures for Pentane and Toluene...

Figure 1. Pressure -Temperature Projection of Vapor Pressure Curve for Pentane and Solid-Liquid-Gas Equilibrium Curve for Pentane-TPP Mixtures.

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