Ethanol vapor pressure

A technique of making known vapor concentrations of reasonably volatile liquids in a diluent gas involves the use of the vapor pressure of the liquid (30). The diluent gas is passed through successive thermostatted bubblers obtaining a mixture determined by the saturation vapor pressure. Thus for ethanol, if the bubblers were maintained at 20°C (ethanol vapor pressure at 20°C... 

The maximum (or saturation) mole fraction, y, of ethanol in the air is determined from the ethanol vapor pressure... 

Figure 74 Reversible conformational transition caused by variation in the ethanol vapor pressure in the surrounding atmosphere, as visualized by AFM. When the extended, tightly adsorbed PnBA brush molecules are exposed to ethanol vapor, the macromolecules swell and contract to form compact globules. Exposure to a humid atmosphere caused the molecules to extend again to a worm-like 2D conformation. The sequence of phase images demonstrates two cycles (first a-d second e-h) of collapse and subsequent extension for three individual PnBA brush molecules on mica in vapors saturated with humidified ethanol (80vol.%) and water. Reprinted from Gallyamov, M. 0. Tartsch, B. Khokhlov, A. R. etal. Chem. Eur. J. 2004,70(18), 4599-4605, with permission from Wiley-VCH. " ...

A canned heat product used to warm buffet dishes consists of a homogeneous mixture of ethanol (C2H5OH) and paraffin, which has an average formula of C24H50. What mass of C2H5OH should be added to 620 kg of the paraffin to produce 8 torr of ethanol vapor pressure at 35 °C The vapor pressure of pure ethanol at 35 °C is 100 torr. 

Fig. XI-11. Relation of adsorption from binary liquid mixtures to the separate vapor pressure adsorption isotherms, system ethanol-benzene-charcoal (n) separate mixed-vapor isotherms (b) calculated and observed adsorption from liquid mixtures. (From Ref. 143.)...

For these reasons, ethanol is most likely to find use as a motor fuel in the form of a gasoline additive, either as ethanol or ethanol-based ethers. In these blend uses, ethanol can capture the high market value of gasoline components that provide high octane and reduced vapor pressure. 

A summary of physical properties of ethyl alcohol is presented ia Table 1. Detailed information on the vapor pressure, density, and viscosity of ethanol can be obtained from References 6—14. A listing of selected biaary and ternary azeotropes of ethanol is compiled ia Reference 15. 

Table 13-1, based on the binary-system activity-coefficient-eqnation forms given in Table 13-3. Consistent Antoine vapor-pressure constants and liquid molar volumes are listed in Table 13-4. The Wilson equation is particularly useful for systems that are highly nonideal but do not undergo phase splitting, as exemplified by the ethanol-hexane system, whose activity coefficients are snown in Fig. 13-20. For systems such as this, in which activity coefficients in dilute regions may...

The partial pressure of LEL ethanol is 0.0327 atm. The temperature that produces a vapor pressure of 0.0327 atm is I l C. which is our predicted flash point. This is close to the reported 13°C. 

This procedure is commonly used to calculate vapor pressures and activities for volatile mixtures. For example, it was used to determine the vapor pressures for the (ethanol + water) system shown in Figure 6.7. 

P7.1 Vapor pressure data for ethanol (1) + 1,4-dioxane (2) at T = 323.15 K is given in the following table, where. vq is the mole fraction in the liquid phase and y is the mole fraction in the vapor phase. 

The vapor pressure of ethanol at 34.9°C is 13.3 kPa. Use the data in Table 6.3 to estimate the normal boiling point of ethanol. 

Sfi.f-Test 8.1 IB Calculate the vapor pressure of ethanol in kilopascals (kPa) at 19°C for a solution prepared by dissolving 2.00 g of cinnamaldehyde, C9HkO, in 50.0 g of ethanol, C2F-I5OH. The vapor pressure of pure ethanol at that temperature is 5.3 kPa. 

The following three sections of this chapter examine how the vapor pressure varies with composition when both components of a mixture are volatile and how that information can be used to separate them by distillation. Distillation, which we first encountered in Section G, is used to separate the many compounds that make up petroleum and to purify alternative fuels such as ethanol and methanol. 

FIGURE 8.40 A graphical illustration of the variation in the vapor pressures of (a) a mixture of ethanol and benzene and (b> a mixture of acetone and chloroform. Note that the mixture in part (ai shows a vapor-pressure maximum and therefore displays a positive deviation front Raoult s law. The one in part (hi shows a minimum and hence displays a negative deviation from Raoult s law. 

The vapor pressure of ethanol at 25°C is 58.9 Torr. A sample of ethanol vapor at 25°C and 58.9 Torr partial pressure is in equilibrium with a very small amount of liquid ethanol in a 10.0-L container also containing dry air, at a total pressure of 750.0 Torr. The volume of the container is then reduced at constant temperature to 5.0 1,. (a) What is the partial pressure of ethanol in the smaller volume Explain your reasoning. 

Alcohols with low molar masses are liquids, and alcohols have much lower vapor pressures than do hydrocarbons with approximately the same molar mass. For example, ethanol is a liquid at room temperature, but butane, which has a higher molar mass than ethanol, is a gas. The relatively low volatility of alcohols is a sign of the strength of hydrogen bonds. The ability of alcohols to form hydrogen bonds also accounts for the solubility in water of alcohols with low molar mass. 

Solvent Injection The solvent injection technique involves the injection of solutions of lipid in solvents with high vapor pressure (ether, fluorocarbons, ethanol) into excess aqueous phase under reduced pressure. In general, the aqueous phase is maintained above the phase transition of the lipids (Te) and a reduced pressure... 

Hydrolysis products With an excess of water by weight, QL form 2-diisopropylaminoethanol, ethanol, and methyl phosphorous acid. With traces of water or other proton donors QL will produce diethylmethyl phosphonite and 0,0 -bis-(2-diisopropylaminoethyl) methylphosphonite. Diethylmethyl phosphonite has a boiling point of 120°C and a vapor pressure of 11 mmHg at 20°C and is highly flammable. 

Greater tendency to partition into the vapor phase from the nonaqueous phase (vapor pressure) (with the exception of TBA, ethanol, and TAME). 

The vapor pressures of most oxygenates, with the exception of ethanol, TBA, and TAME, can result in them being more readily volatilized from soil using certain technologies, such as SVE or MPE.25-26... 

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