Eicosane pressure

Burdick and Jackson). All solutions were photolyzed to less than 5% conversion in a standard 3 ml capacity, 1-cm path length quartz cell. Samples were irradiated with a 450-Watt medium pressure, Hanovla mercury lamp focused through an appropriate band-pass filter (280 nm or 254 nm) onto the 1-cm quartz cell with the requisite solution. Test solutions could be purged with either helium or oxygen using a needle valve assembly attached to the tapered quartz cell neck. The loss of carbamate due to photolysis and the amounts of known photoproducts were determined quantitatively by GC using eicosane as an internal standard. The columns were 6 stainless steel containing Carbowax 20M on chromosorb G. 

FIGURE 2.1.1.1.35.1 Logarithm of vapor pressure versus reciprocal temperature for n-eicosane. 

Chirico, R.D, Nguyen, A., Steele, W.V., Strube, M.M. (1989) Vapor pressure of n-alkanes revisited. New high-precision vapor pressure data on ra-decane, ra-eicosane, and n-octacosane. J. Chem. Eng. Data 34, 149-156. 

Let us now perform a little experiment with n-eicosane. We place pure (solid) n-eicosane at 25°C in an open vessel (vessel 1, Fig. 4.3a) and in a closed vessel (vessel 2, Fig. 4.3b). In the open vessel we have an ambient total pressure of 1 atm or... 

Drugs (Free base) Eicosane Dibutyl phthalate Vapor pressures (Torr, at 25%C)... 

Figures Supercritical fluid chromatography (SFC) with COj as a mobile phase capacity ratio k as a function of density p and pressure p see text Q0H22 = decane, Ci,Ha = hexadecane, CaoH4a = eicosane, CjoH 2 = 2,6.10,15,19,23-Aexame/A /-tetracosane)...

Chappelow and Prausnitz (15) measured the low-pressure solubilities of methane, ethane, propane, n-butane, iso-butane and hydrogen in n-hexadecane, n-eicosane, squalqne, bicyclohexyl, octamethylcyclotetraxiloxane, diphenylmethane and 1-methylnaphtha-lene over the temperature range 25 to 200 °C. They used an apparatus as that used by Cukor and Prausnitz (27). 

The simulations described above were performed at constant density, i.e., a volume was imposed on the system irrespective of the resulting pressure or chemical potential. MD simulations performed at constant chemical potential, where the confined liquid is in equilibrium with a vapor or bulk liquid phase, have also been performed. Simulations with free surfaces, i.e., with vapor/polymer interfaces, allow for the study of the equilibrium liquid-vapor interface structure and the calculation of the surface tension, a thermodynamic property fundamental to the understanding of the behavior of a material at interfaces. An MD study of the equilibrium liquid-vapor interface structure and surface tension of thin films of n-decane and n-eicosane (C20H42) has been performed in Ref. 26. The system studied consisted of a box with periodic boundary conditions in all directions. The liquid polymer, however, while fully occupying the x and y dimensions, occupied only a fraction of the system in the z direction, resulting in two liquid-vapor interfaces. The liquid phase ranged from about 4.0 to 7.0 nm in thickness. Simulations were performed at 400 K for both decane and eicosane, with additional decane simulations at 300 K. A similar system of tridecane molecules, using a well calibrated EA force field, has been studied at 400 K and 300 K in Ref 32. 

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